Merge pull request #242 from 0X1A/master

Fix issues with CMake package configuration when used with vcpkg #110

.circleci/config.yml

@@ -0,0 +1,88 @@
+version: 2.1
+
+jobs:
+  test_suite:
+    docker:
+      - image: cimg/go:1.16
+    steps:
+      - checkout
+      - run:
+          command: |
+              g++ --version
+              cd tests/
+              g++ -std=c++11 -O2 -Wall -Wextra -Werror -I../ check_toml_test.cpp -o check_toml_test
+              export PATH=$(pwd):${PATH}
+              git clone --depth 1 --branch v1.3.0 https://github.com/BurntSushi/toml-test.git
+              cd toml-test/
+              go install -v ./cmd/toml-test
+              cd -
+              toml-test check_toml_test
+#               go clean -modcache
+#               go get github.com/BurntSushi/toml-test/cmd/toml-test
+#               $GOPATH/bin/toml-test ./check_toml_test
+  test_serialization:
+    docker:
+      - image: circleci/buildpack-deps:bionic
+    steps:
+      - checkout
+      - run:
+          command: |
+              g++ --version
+              cd tests/
+              g++ -std=c++11 -O2 -Wall -Wextra -Wpedantic -Werror -I../ check_serialization.cpp -o check_serialization
+              git clone https://github.com/BurntSushi/toml-test.git
+              cp check_serialization toml-test/tests/valid
+              cd toml-test/tests/valid
+              for f in $(ls ./*.toml);
+                do echo "==> ${f}";
+                cat ${f};
+                echo "---------------------------------------";
+                ./check_serialization ${f};
+                if [ $? -ne 0 ] ; then
+                  exit 1
+                fi
+                echo "=======================================";
+              done
+  output_result:
+    docker:
+      - image: circleci/buildpack-deps:bionic
+    steps:
+      - checkout
+      - run:
+          command: |
+              g++ --version
+              cd tests/
+              g++ -std=c++11 -O2 -Wall -Wextra -Wpedantic -Werror -I../ check.cpp -o check
+              git clone https://github.com/BurntSushi/toml-test.git
+              cp check toml-test/tests/invalid
+              cp check toml-test/tests/valid
+              cd toml-test/tests/invalid
+              for f in $(ls ./*.toml);
+                do echo "==> ${f}";
+                cat ${f};
+                echo "---------------------------------------";
+                ./check ${f} invalid;
+                if [ $? -ne 0 ] ; then
+                  exit 1
+                fi
+                echo "=======================================";
+              done
+              cd ../valid
+              for f in $(ls ./*.toml);
+                do echo "==> ${f}";
+                cat ${f};
+                echo "---------------------------------------";
+                ./check ${f} valid;
+                if [ $? -ne 0 ] ; then
+                  exit 1
+                fi
+                echo "=======================================";
+              done
+
+workflows:
+  version: 2.1
+  test:
+    jobs:
+      - test_suite
+      - test_serialization
+      - output_result

.clusterfuzzlite/Dockerfile

@@ -0,0 +1,6 @@
+FROM gcr.io/oss-fuzz-base/base-builder
+RUN apt-get update && apt-get install -y make autoconf automake libtool
+
+COPY . $SRC/toml11
+COPY .clusterfuzzlite/build.sh $SRC/build.sh
+WORKDIR $SRC/toml11

.clusterfuzzlite/README.md

@@ -0,0 +1,3 @@
+# ClusterFuzzLite set up
+
+This folder contains a fuzzing set for [ClusterFuzzLite](https://google.github.io/clusterfuzzlite).

.clusterfuzzlite/build.sh

@@ -0,0 +1,6 @@
+#!/bin/bash -eu
+# Copy fuzzer executable to $OUT/
+$CXX $CFLAGS $LIB_FUZZING_ENGINE \
+  $SRC/toml11/.clusterfuzzlite/parse_fuzzer.cpp \
+  -o $OUT/parse_fuzzer \
+  -I$SRC/toml11/

.clusterfuzzlite/parse_fuzzer.cpp

@@ -0,0 +1,16 @@
+
+#include <toml.hpp>
+
+#include <sstream>
+#include <string>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  std::string s(reinterpret_cast<const char *>(data), size);
+  std::istringstream iss(s);
+  try {
+    const auto ref = toml::parse(iss);
+  } catch (...) {
+  }
+
+  return 0;
+}

.clusterfuzzlite/project.yaml

@@ -0,0 +1 @@
+language: c++

.editorconfig

@@ -0,0 +1,13 @@
+root = true
+
+[*]
+indent_style = space
+
+[CMakeLists.txt]
+indent_size = 4
+
+[*.{c,h}*]
+indent_size = 4
+
+[*.{md,yml}]
+indent_size = 2

.github/workflows/cflite_pr.yml

@@ -0,0 +1,30 @@
+name: ClusterFuzzLite PR fuzzing
+on:
+  workflow_dispatch:
+  pull_request:
+    branches: [ master ]
+permissions: read-all
+jobs:
+  PR:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        sanitizer: [address]
+    steps:
+    - name: Build Fuzzers (${{ matrix.sanitizer }})
+      id: build
+      uses: google/clusterfuzzlite/actions/build_fuzzers@v1
+      with:
+        sanitizer: ${{ matrix.sanitizer }}
+        language: c++
+        bad-build-check: false
+    - name: Run Fuzzers (${{ matrix.sanitizer }})
+      id: run
+      uses: google/clusterfuzzlite/actions/run_fuzzers@v1
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}
+        fuzz-seconds: 240
+        mode: 'code-change'
+        report-unreproducible-crashes: false
+        sanitizer: ${{ matrix.sanitizer }}

.github/workflows/main.yml

@@ -0,0 +1,256 @@
+name: build
+
+on: [push, pull_request]
+
+jobs:
+  build-linux-gcc:
+    runs-on: Ubuntu-22.04
+    strategy:
+      matrix:
+        compiler: ['g++-12', 'g++-11', 'g++-10', 'g++-9']
+        standard: ['11', '14', '17', '20']
+        unreleased: ['ON', 'OFF']
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install
+        run: |
+            sudo apt-add-repository ppa:ubuntu-toolchain-r/test
+            sudo apt-get update
+            sudo apt-get install libboost-test-dev
+            sudo apt-get install language-pack-fr # test serializer w/ locale
+            sudo apt-get install ${{ matrix.compiler }}
+      - name: Configure
+        run: |
+            mkdir build && cd build
+            cmake .. -Dtoml11_BUILD_TEST=ON -DCMAKE_CXX_COMPILER=${{ matrix.compiler }} -DCMAKE_CXX_STANDARD=${{ matrix.standard }} -DTOML11_USE_UNRELEASED_TOML_FEATURES=${{ matrix.unreleased }}
+      - name: Build
+        run: |
+            cd build && cmake --build .
+      - name: Test
+        run: |
+            cd build && ctest --output-on-failure
+  build-linux-clang:
+    runs-on: Ubuntu-22.04
+    strategy:
+      matrix:
+        compiler: ['15', '14', '13', '12', '11']
+        standard: ['11', '14', '17', '20']
+        unreleased: ['ON', 'OFF']
+        exclude:
+            - {compiler: '14', standard: '20'} # to avoid using gcc-13 libstdc++
+            - {compiler: '13', standard: '20'} # with older clang
+            - {compiler: '12', standard: '20'}
+            - {compiler: '11', standard: '20'}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install
+        run: |
+            sudo apt-add-repository ppa:ubuntu-toolchain-r/test
+            sudo apt-get update
+            sudo apt-get install libboost-test-dev
+            sudo apt-get install language-pack-fr # test serializer w/ locale
+            sudo apt-get install clang-${{ matrix.compiler }}
+      - name: Configure
+        run: |
+            mkdir build && cd build
+            cmake .. -Dtoml11_BUILD_TEST=ON -DCMAKE_C_COMPILER=clang-${{ matrix.compiler }} -DCMAKE_CXX_COMPILER=clang++-${{ matrix.compiler }} -DCMAKE_CXX_STANDARD=${{ matrix.standard }} -DTOML11_USE_UNRELEASED_TOML_FEATURES=${{ matrix.unreleased }}
+      - name: Build
+        run: |
+            cd build && cmake --build .
+      - name: Test
+        run: |
+            cd build && ctest --output-on-failure
+
+  build-linux-old-gcc:
+    runs-on: Ubuntu-20.04
+    strategy:
+      matrix:
+        compiler: ['g++-8', 'g++-7']
+        standard: ['11', '14', '17', '20']
+        unreleased: ['ON', 'OFF']
+        exclude:
+            - {compiler: 'g++-7', standard: '20'}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install
+        run: |
+            sudo apt-add-repository ppa:ubuntu-toolchain-r/test
+            sudo apt-get update
+            sudo apt-get install libboost-test-dev
+            sudo apt-get install language-pack-fr # test serializer w/ locale
+            sudo apt-get install ${{ matrix.compiler }}
+      - name: Configure
+        run: |
+            mkdir build && cd build
+            if [[ "${{ matrix.compiler }}" == "g++-8" && ( "${{ matrix.standard }}" == "17" || "${{ matrix.standard }}" == "20" ) ]] ; then
+                cmake .. -Dtoml11_BUILD_TEST=ON -DCMAKE_CXX_COMPILER=${{ matrix.compiler }} -DCMAKE_CXX_STANDARD=${{ matrix.standard }} -DTOML11_REQUIRE_FILESYSTEM_LIBRARY=ON -DTOML11_USE_UNRELEASED_TOML_FEATURES=${{ matrix.unreleased }}
+            else
+                cmake .. -Dtoml11_BUILD_TEST=ON -DCMAKE_CXX_COMPILER=${{ matrix.compiler }} -DCMAKE_CXX_STANDARD=${{ matrix.standard }} -DTOML11_USE_UNRELEASED_TOML_FEATURES=${{ matrix.unreleased }}
+            fi
+      - name: Build
+        run: |
+            cd build && cmake --build .
+      - name: Test
+        run: |
+            cd build && ctest --output-on-failure
+
+  build-linux-old-clang:
+    runs-on: Ubuntu-20.04
+    strategy:
+      matrix:
+        compiler: ['10', '9', '8', '7', '6.0']
+        standard: ['11', '14', '17', '20']
+        unreleased: ['ON', 'OFF']
+        exclude:
+            - {compiler: '6.0', standard: '20'}
+            - {compiler: '7',   standard: '20'}
+            - {compiler: '8',   standard: '20'}
+            - {compiler: '9',   standard: '20'}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install
+        run: |
+            sudo apt-add-repository ppa:ubuntu-toolchain-r/test
+            sudo apt-get update
+            sudo apt-get install libboost-test-dev
+            sudo apt-get install language-pack-fr # test serializer w/ locale
+            sudo apt-get install clang-${{ matrix.compiler }}
+      - name: Configure
+        run: |
+            mkdir build && cd build
+            cmake .. -Dtoml11_BUILD_TEST=ON -DCMAKE_C_COMPILER=clang-${{ matrix.compiler }} -DCMAKE_CXX_COMPILER=clang++-${{ matrix.compiler }} -DCMAKE_CXX_STANDARD=${{ matrix.standard }} -DTOML11_USE_UNRELEASED_TOML_FEATURES=${{ matrix.unreleased }}
+      - name: Build
+        run: |
+            cd build && cmake --build .
+      - name: Test
+        run: |
+            cd build && ctest --output-on-failure
+
+#  build-osx-13-arm64:
+#    runs-on: macos-13-arm64
+#    strategy:
+#      matrix:
+#        standard: ['11', '14', '17', '20']
+#        unreleased: ['ON', 'OFF']
+#    steps:
+#      - name: Checkout
+#        uses: actions/checkout@v4
+#        with:
+#          submodules: true
+#      - name: Install
+#        run: |
+#            brew install boost
+#      - name: Configure
+#        run: |
+#            mkdir build && cd build
+#            cmake .. -Dtoml11_BUILD_TEST=ON -DCMAKE_CXX_STANDARD=${{ matrix.standard }} -DTOML11_USE_UNRELEASED_TOML_FEATURES=${{ matrix.unreleased }}
+#      - name: Build
+#        run: |
+#            cd build && cmake --build .
+#      - name: Test
+#        run: |
+#            cd build && ctest --output-on-failure
+
+  build-osx-13:
+    runs-on: macos-13
+    strategy:
+      matrix:
+        standard: ['11', '14', '17', '20']
+        unreleased: ['ON', 'OFF']
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install
+        run: |
+            brew install boost
+        env:
+          HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK: 1
+      - name: Configure
+        run: |
+            mkdir build && cd build
+            cmake .. -Dtoml11_BUILD_TEST=ON -DCMAKE_CXX_STANDARD=${{ matrix.standard }} -DTOML11_USE_UNRELEASED_TOML_FEATURES=${{ matrix.unreleased }}
+      - name: Build
+        run: |
+            cd build && cmake --build .
+      - name: Test
+        run: |
+            cd build && ctest --output-on-failure
+
+  build-osx-12:
+    runs-on: macos-12
+    strategy:
+      matrix:
+        standard: ['11', '14', '17', '20']
+        unreleased: ['ON', 'OFF']
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install
+        run: |
+            brew install boost
+      - name: Configure
+        run: |
+            mkdir build && cd build
+            cmake .. -Dtoml11_BUILD_TEST=ON -DCMAKE_CXX_STANDARD=${{ matrix.standard }} -DTOML11_USE_UNRELEASED_TOML_FEATURES=${{ matrix.unreleased }}
+      - name: Build
+        run: |
+            cd build && cmake --build .
+      - name: Test
+        run: |
+            cd build && ctest --output-on-failure
+
+  build-windows-msvc:
+    runs-on: windows-2022
+    strategy:
+      matrix:
+        standard: ['11', '14', '17', '20']
+        config: ['Release', 'Debug']
+        unreleased: ['ON', 'OFF']
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install
+        run: |
+            (New-Object System.Net.WebClient).DownloadFile("https://github.com/actions/boost-versions/releases/download/1.72.0-20200608.4/boost-1.72.0-win32-msvc14.2-x86_64.tar.gz", "$env:TEMP\\boost.tar.gz")
+            7z.exe x "$env:TEMP\\boost.tar.gz" -o"$env:TEMP\\boostArchive" -y | Out-Null
+            7z.exe x "$env:TEMP\\boostArchive" -o"$env:TEMP\\boost" -y | Out-Null
+            Push-Location -Path "$env:TEMP\\boost"
+            Invoke-Expression .\\setup.ps1
+      - uses: ilammy/msvc-dev-cmd@v1
+      - name: Configure
+        shell: cmd
+        run: |
+            file --mime-encoding tests/test_literals.cpp
+            mkdir build
+            cd build
+            cmake ../ -G "NMake Makefiles" -Dtoml11_BUILD_TEST=ON -DCMAKE_CXX_STANDARD=${{ matrix.standard }} -DBoost_NO_BOOST_CMAKE=ON -DBOOST_ROOT="C:\\hostedtoolcache\\windows\\Boost\\1.72.0\\x86_64" -DTOML11_USE_UNRELEASED_TOML_FEATURES=${{ matrix.unreleased }}
+      - name: Build
+        working-directory: ./build
+        run: |
+            cmake --build . --config "${{ matrix.config }}"
+      - name: Test
+        working-directory: ./build
+        run: |
+            file --mime-encoding tests/toml/tests/example.toml
+            file --mime-encoding tests/toml/tests/fruit.toml
+            file --mime-encoding tests/toml/tests/hard_example.toml
+            file --mime-encoding tests/toml/tests/hard_example_unicode.toml
+            ctest --build-config "${{ matrix.config }}" --output-on-failure

.travis.yml

@@ -1,42 +0,0 @@
-dist: trusty
-
-matrix:
-  include:
-  - os: linux
-    language: cpp
-    compiler: gcc
-    env: COMPILER="g++-5"
-    addons:
-      apt:
-        sources:
-        - ubuntu-toolchain-r-test
-        packages:
-        - g++-5
-        - build-essential
-        - cmake
-        - libboost-all-dev
-  - os: linux
-    language: cpp
-    compiler: clang
-    env: COMPILER="clang++-3.7"
-    addons:
-      apt:
-        sources:
-        - ubuntu-toolchain-r-test
-        - llvm-toolchain-precise-3.7
-        packages:
-        - clang-3.7
-        - build-essential
-        - cmake
-        - libboost-all-dev
-  - os: osx
-    language: cpp
-    compiler: clang
-
-script:
-- mkdir build
-- cd build
-- git clone https://github.com/toml-lang/toml.git
-- cmake -DCMAKE_CXX_COMPILER=$COMPILER ..
-- make
-- ctest --output-on-failure

CMakeLists.txt

@@ -1,35 +1,87 @@
-cmake_minimum_required(VERSION 2.8)
+cmake_minimum_required(VERSION 3.5)
 enable_testing()
-project(toml11)
 
-include(CheckCXXCompilerFlag)
-if("${CMAKE_VERSION}" VERSION_GREATER 3.1)
-    set(CMAKE_CXX_STANDARD 11)
-    set(CXX_STANDARD_REQUIRED ON)
-else()
-    # Manually check for C++11 compiler flag.
-    CHECK_CXX_COMPILER_FLAG("-std=c++11" COMPILER_SUPPORTS_CXX11)
-    CHECK_CXX_COMPILER_FLAG("-std=c++0x" COMPILER_SUPPORTS_CXX0X)
-    CHECK_CXX_COMPILER_FLAG("-std=gnu++11" COMPILER_SUPPORTS_GNU11)
-    CHECK_CXX_COMPILER_FLAG("-std=gnu++0x" COMPILER_SUPPORTS_GNU0X)
-    if(COMPILER_SUPPORTS_CXX11)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
-    elseif(COMPILER_SUPPORTS_CXXOX)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")
-    elseif(COMPILER_SUPPORTS_GNU11)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")
-    elseif(COMPILER_SUPPORTS_GNU0X)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++0x")
+project(toml11 VERSION 3.8.1)
+
+option(toml11_BUILD_TEST "Build toml tests" OFF)
+option(toml11_INSTALL "Install CMake targets during install step." ON)
+option(toml11_TEST_WITH_ASAN  "use LLVM address sanitizer" OFF)
+option(toml11_TEST_WITH_UBSAN "use LLVM undefined behavior sanitizer" OFF)
+
+option(TOML11_USE_UNRELEASED_TOML_FEATURES
+    "use features in toml-lang/toml master while testing" OFF)
+
+if(MSVC)
+#     add_definitions("/Zc:__cplusplus")  # define __cplusplus value correctly
+    add_definitions("/utf-8")           # enable to use u8"" literal
+    if(MSVC_VERSION LESS 1910)
+        message(STATUS "MSVC < 1910. DEFINE_CONVERSION_NON_INTRUSIVE is disabled")
+        add_definitions(-DTOML11_WITHOUT_DEFINE_NON_INTRUSIVE)
+    elseif(MSVC_VERSION LESS 1920)
+        add_definitions("/experimental:preprocessor") # MSVC 2017
     else()
-        if(MSVC)
-            if(MSVC_VERSION LESS 1900)
-                message(SEND_ERROR "MSVC < 14.0 is not supported. Please update your compiler or use mingw")
-            endif()
-        else()
-            message(SEND_ERROR "The ${CMAKE_CXX_COMPILER} compiler lacks C++11 support. Use another compiler.")
-        endif()
+        add_definitions("/Zc:preprocessor") # MSVC 2019
     endif()
 endif()
 
-include_directories(${PROJECT_SOURCE_DIR})
-add_subdirectory(tests)
+# Set some common directories
+include(GNUInstallDirs)
+set(toml11_install_cmake_dir         ${CMAKE_INSTALL_LIBDIR}/cmake/toml11)
+set(toml11_install_include_dir       ${CMAKE_INSTALL_INCLUDEDIR})
+set(toml11_config_dir                ${CMAKE_CURRENT_BINARY_DIR}/cmake/)
+set(toml11_config                    ${toml11_config_dir}/toml11Config.cmake)
+set(toml11_config_version            ${toml11_config_dir}/toml11ConfigVersion.cmake)
+
+add_library(toml11 INTERFACE)
+target_include_directories(toml11 INTERFACE
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+    $<INSTALL_INTERFACE:${toml11_install_include_dir}>
+)
+add_library(toml11::toml11 ALIAS toml11)
+
+# Write config and version config files
+include(CMakePackageConfigHelpers)
+write_basic_package_version_file(
+    ${toml11_config_version}
+    VERSION ${toml11_VERSION}
+    COMPATIBILITY SameMajorVersion
+)
+
+if (toml11_INSTALL)
+    configure_package_config_file(
+        cmake/toml11Config.cmake.in
+        ${toml11_config}
+        INSTALL_DESTINATION ${toml11_install_cmake_dir}
+        PATH_VARS toml11_install_cmake_dir
+    )
+
+    # Install config files
+    install(FILES ${toml11_config} ${toml11_config_version}
+        DESTINATION ${toml11_install_cmake_dir}
+    )
+
+    # Install header files
+    install(
+        FILES toml.hpp
+        DESTINATION "${toml11_install_include_dir}"
+    )
+    install(
+        DIRECTORY "toml"
+        DESTINATION "${toml11_install_include_dir}"
+        FILES_MATCHING PATTERN "*.hpp"
+    )
+
+    # Export targets and install them
+    install(TARGETS toml11
+        EXPORT toml11Targets
+    )
+    install(EXPORT toml11Targets
+        FILE toml11Targets.cmake
+        DESTINATION ${toml11_install_cmake_dir}
+        NAMESPACE toml11::
+    )
+endif()
+
+if (toml11_BUILD_TEST)
+    add_subdirectory(tests)
+endif ()

PROPOSAL.md

@@ -1,59 +0,0 @@
-
-### encoding user's data
-
-You can encode your data to toml format.
-
-```cpp
-const toml::value integer(1);
-const toml::value array{3.1, 3.14, 3.141, 3.1415};
-const toml::value table{{"answer", 42}, {"pi", 3.14}, {"string", "foobar"}};
-
-std::cout << toml::format("integer", integer) << std::endl;
-std::cout << toml::format("array",   array)   << std::endl;
-std::cout << toml::format("table",   table)   << std::endl;
-```
-
-this program will output as below.
-
-```toml
-integer = 1
-array = [3.1, 3.14, 3.141, 3.1415]
-[table]
-answer = 42
-pi = 3.14
-string = "foobar"
-```
-
-Without key name, you can make string formatted as toml.
-
-```cpp
-const std::string integer_ = toml::format(integer); // "1"
-const std::string array_   = toml::format(array);   // "[3.1, 3.14, 3.141, 3.1415]"
-const std::string table_   = toml::format(table);   // "answer = 42\npi=3.14\nstring=foobar"
-```
-
-### inlinize
-
-You can make `toml::Table` inline.
-
-```cpp
-const toml::value table{{"answer", 42}, {"pi", 3.14}, {"string", "foobar"}};
-// if the inline-table format length is less than 80, the table will be inlined
-std::cout << toml::format("table", table, toml::make_inline(80)) << std::endl;
-// In any case, the table will be inlined.
-std::cout << toml::format("table", table, toml::forceinline) << std::endl;
-```
-
-```toml
-table = {answer = 42, pi = 3.14, string = "foobar"}
-```
-
-And there are some stream manipulators for toml format.
-
-```cpp
-const toml::value table{{"answer", 42}, {"pi", 3.14}, {"string", "foobar"}};
-// if the inline-table format length is less than 80, the table will be inlined
-std::cout << toml::make_inline(80) << table << std::endl;
-// In any case, the table will be inlined.
-std::cout << toml::forceinline << table << std::endl;
-```

appveyor.yml

@@ -17,10 +17,9 @@ build_script:
   - cd C:\toml11
   - mkdir build
   - cd build
-  - git clone https://github.com/toml-lang/toml.git
-  - file --mime-encoding toml/tests/hard_example_unicode.toml
-  - cmake -G"%generator%" -DBOOST_ROOT=C:/Libraries/boost_1_63_0 ..
+  - cmake -G"%generator%" -DCMAKE_CXX_STANDARD=11 -DBOOST_ROOT=C:/Libraries/boost_1_69_0 -Dtoml11_BUILD_TEST=ON ..
   - cmake --build . --config "%configuration%"
+  - file --mime-encoding tests/toml/tests/hard_example_unicode.toml
 
 test_script:
   - ctest --build-config "%configuration%" --timeout 300 --output-on-failure

cmake/toml11Config.cmake.in

@@ -0,0 +1,2 @@
+@PACKAGE_INIT@
+include("${CMAKE_CURRENT_LIST_DIR}/toml11Targets.cmake")

tests/CMakeLists.txt

@@ -1,5 +1,24 @@
+include(ExternalProject)
+
+set(TOML11_LANGSPEC_GIT_REPOSITORY "https://github.com/toml-lang/toml" CACHE STRING
+    "URL of the TOML language specification repository")
+
+set(TOML11_LANGSPEC_SOURCE_DIR "${CMAKE_CURRENT_BINARY_DIR}/toml" CACHE FILEPATH
+    "directory for the TOML language specification tree")
+
+if(NOT EXISTS "${TOML11_LANGSPEC_SOURCE_DIR}/toml.abnf")
+    ExternalProject_Add(toml
+        SOURCE_DIR "${TOML11_LANGSPEC_SOURCE_DIR}"
+        GIT_REPOSITORY "${TOML11_LANGSPEC_GIT_REPOSITORY}"
+        GIT_TAG "v0.5.0"
+        CONFIGURE_COMMAND ""
+        BUILD_COMMAND ""
+        INSTALL_COMMAND "")
+endif()
+
 set(TEST_NAMES
     test_datetime
+    test_string
     test_utility
     test_result
     test_traits
@@ -20,25 +39,169 @@ set(TEST_NAMES
     test_parse_inline_table
     test_parse_key
     test_parse_table_key
+    test_literals
+    test_comments
     test_get
-    test_get_related_func
-    test_to_toml
-    test_from_toml
+    test_get_or
+    test_find
+    test_find_or
+    test_find_or_recursive
+    test_expect
     test_parse_file
+    test_serialize_file
     test_parse_unicode
     test_error_detection
+    test_format_error
+    test_extended_conversions
 )
 
-CHECK_CXX_COMPILER_FLAG("-Wall" COMPILER_SUPPORTS_WALL)
+include(CheckCXXCompilerFlag)
+
+CHECK_CXX_COMPILER_FLAG("-Wall"      COMPILER_SUPPORTS_WALL)
+CHECK_CXX_COMPILER_FLAG("-Wextra"    COMPILER_SUPPORTS_WEXTRA)
 CHECK_CXX_COMPILER_FLAG("-Wpedantic" COMPILER_SUPPORTS_WPEDANTIC)
+CHECK_CXX_COMPILER_FLAG("-Werror"    COMPILER_SUPPORTS_WERROR)
+
+CHECK_CXX_COMPILER_FLAG("-Wsign-conversion"     COMPILER_SUPPORTS_WSIGN_CONVERSION)
+CHECK_CXX_COMPILER_FLAG("-Wconversion"          COMPILER_SUPPORTS_WCONVERSION)
+CHECK_CXX_COMPILER_FLAG("-Wduplicated-cond"     COMPILER_SUPPORTS_WDUPLICATED_COND)
+CHECK_CXX_COMPILER_FLAG("-Wduplicated-branches" COMPILER_SUPPORTS_WDUPLICATED_BRANCHES)
+CHECK_CXX_COMPILER_FLAG("-Wlogical-op"          COMPILER_SUPPORTS_WLOGICAL_OP)
+CHECK_CXX_COMPILER_FLAG("-Wuseless-cast"        COMPILER_SUPPORTS_WUSELESS_CAST)
+CHECK_CXX_COMPILER_FLAG("-Wdouble-promotion"    COMPILER_SUPPORTS_WDOUBLE_PROMOTION)
+CHECK_CXX_COMPILER_FLAG("-Wrange-loop-analysis" COMPILER_SUPPORTS_WRANGE_LOOP_ANALYSIS)
+CHECK_CXX_COMPILER_FLAG("-Wundef"               COMPILER_SUPPORTS_WUNDEF)
+CHECK_CXX_COMPILER_FLAG("-Wshadow"              COMPILER_SUPPORTS_WSHADOW)
+
+include(CheckCXXSourceCompiles)
+
+# check which standard library implementation is used. If libstdc++ is used,
+# it will fail to compile. It compiles if libc++ is used.
+check_cxx_source_compiles("
+#include <cstddef>
+#ifdef __GLIBCXX__
+    static_assert(false);
+#endif
+int main() {
+    return 0;
+}" TOML11_WITH_LIBCXX_LIBRARY)
+
+# LLVM 8 requires -lc++fs if compiled with libc++ to use <filesystem>.
+# LLVM 9+ does not require any special library.
+# GCC 8 requires -lstdc++fs. GCC 9+ does not require it.
+#
+# Yes, we can check the version of the compiler used in the current build
+# directly in CMake. But, in most cases, clang build uses libstdc++ as the
+# standard library implementation and it makes the condition complicated.
+# In many environment, the default installed C++ compiler is GCC and libstdc++
+# is installed along with it. In most build on such an environment, even if we
+# chose clang as the C++ compiler, still libstdc++ is used. Checking default
+# gcc version makes the condition complicated.
+# The purpose of this file is to compile tests. We know the environment on which
+# the tests run. We can set this option and, I think, it is easier and better.
+option(TOML11_REQUIRE_FILESYSTEM_LIBRARY "need to link -lstdc++fs or -lc++fs" OFF)
+
+find_package(Boost COMPONENTS unit_test_framework REQUIRED)
+
+set(PREVIOUSLY_REQUIRED_INCLUDES "${CMAKE_REQUIRED_INCLUDES}")
+set(PREVIOUSLY_REQUIRED_LIBRARIES "${CMAKE_REQUIRED_LIBRARIES}")
+set(PREVIOUSLY_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
+
+list(APPEND CMAKE_REQUIRED_INCLUDES ${Boost_INCLUDE_DIRS})
+list(APPEND CMAKE_REQUIRED_LIBRARIES ${Boost_UNIT_TEST_FRAMEWORK_LIBRARY})
+if(APPLE)
+    list(APPEND CMAKE_REQUIRED_FLAGS "-std=c++11")
+endif()
+
+check_cxx_source_compiles("
+#define BOOST_TEST_MODULE \"dummy\"
+#undef BOOST_TEST_DYN_LINK
+#define BOOST_TEST_NO_LIB
+#include <boost/test/included/unit_test.hpp>
+BOOST_AUTO_TEST_CASE(proforma) { BOOST_TEST(true); }
+" TOML11_WITH_BOOST_TEST_HEADER)
+
+check_cxx_source_compiles("
+#define BOOST_TEST_MODULE \"dummy\"
+#undef BOOST_TEST_DYN_LINK
+#undef BOOST_TEST_NO_LIB
+#include <boost/test/unit_test.hpp>
+BOOST_AUTO_TEST_CASE(proforma) { BOOST_TEST(true); }
+" TOML11_WITH_BOOST_TEST_STATIC)
+
+check_cxx_source_compiles("
+#define BOOST_TEST_MODULE \"dummy\"
+#define BOOST_TEST_DYN_LINK
+#undef BOOST_TEST_NO_LIB
+#include <boost/test/unit_test.hpp>
+BOOST_AUTO_TEST_CASE(proforma) { BOOST_TEST(true); }
+" TOML11_WITH_BOOST_TEST_DYNAMIC)
+
+set(CMAKE_REQUIRED_INCLUDES "${PREVIOUSLY_REQUIRED_INCLUDES}")
+set(CMAKE_REQUIRED_LIBRARIES "${PREVIOUSLY_REQUIRED_LIBRARIES}")
+set(CMAKE_REQUIRED_FLAGS "${PREVIOUSLY_REQUIRED_FLAGS}")
+
+unset(PREVIOUSLY_REQUIRED_INCLUDES)
+unset(PREVIOUSLY_REQUIRED_LIBRARIES)
+unset(PREVIOUSLY_REQUIRED_FLAGS)
+
+if(TOML11_WITH_BOOST_TEST_DYNAMIC)
+    add_definitions(-DUNITTEST_FRAMEWORK_LIBRARY_EXIST -DBOOST_TEST_DYN_LINK)
+elseif(TOML11_WITH_BOOST_TEST_STATIC)
+    add_definitions(-DUNITTEST_FRAMEWORK_LIBRARY_EXIST)
+elseif(TOML11_WITH_BOOST_TEST_HEADER)
+    add_definitions(-DBOOST_TEST_NO_LIB)
+else()
+    message(FATAL_ERROR "Neither the Boost.Test static or shared library nor the header-only version seem to be usable.")
+endif()
 
 if(COMPILER_SUPPORTS_WALL)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
 endif()
-
+if(COMPILER_SUPPORTS_WEXTRA)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wextra")
+endif()
 if(COMPILER_SUPPORTS_WPEDANTIC)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wpedantic")
 endif()
+if(COMPILER_SUPPORTS_WERROR)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
+endif()
+if(COMPILER_SUPPORTS_WSHADOW)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wshadow")
+endif()
+if(COMPILER_SUPPORTS_WSIGN_CONVERSION)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-conversion")
+endif()
+if(COMPILER_SUPPORTS_WCONVERSION)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wconversion")
+endif()
+if(COMPILER_SUPPORTS_WDUPLICATED_COND)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wduplicated-cond")
+endif()
+if(COMPILER_SUPPORTS_WDUPLICATED_BRANCHES)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wduplicated-branches")
+endif()
+if(COMPILER_SUPPORTS_WLOGICAL_OP)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wlogical-op")
+endif()
+if(COMPILER_SUPPORTS_WUSELESS_CAST)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wuseless-cast")
+endif()
+if(COMPILER_SUPPORTS_WDOUBLE_PROMOTION)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wdouble-promotion")
+endif()
+if(COMPILER_SUPPORTS_WRANGE_LOOP_ANALYSIS)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wrange-loop-analysis")
+endif()
+if(COMPILER_SUPPORTS_WUNDEF)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wundef")
+endif()
+
+if(TOML11_USE_UNRELEASED_TOML_FEATURES)
+    message(STATUS "adding TOML11_USE_UNRELEASED_TOML_FEATURES flag")
+    add_definitions("-DTOML11_USE_UNRELEASED_TOML_FEATURES")
+endif()
 
 # Disable some MSVC warnings
 if(MSVC)
@@ -76,23 +239,61 @@ if(MSVC)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4820")
     # pragma warning(pop): likely mismatch, popping warning state pushed in different file
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd5031")
+	# pragma warning(pop): spectre warnings in tests
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd5045")
+	# pragma warning(pop): spectre warnings in tests
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4265")
 endif()
 
-find_package(Boost COMPONENTS unit_test_framework REQUIRED)
-add_definitions(-DBOOST_TEST_DYN_LINK)
-add_definitions(-DUNITTEST_FRAMEWORK_LIBRARY_EXIST)
+set(TEST_ENVIRON "TOMLDIR=${TOML11_LANGSPEC_SOURCE_DIR}")
+if(WIN32)
+    # Set the PATH to be able to find Boost DLL
+    STRING(REPLACE ";" "\\;" PATH_STRING "$ENV{PATH}")
+    list(APPEND TEST_ENVIRON "PATH=${PATH_STRING}\;${Boost_LIBRARY_DIRS}")
+endif()
 
 foreach(TEST_NAME ${TEST_NAMES})
     add_executable(${TEST_NAME} ${TEST_NAME}.cpp)
-    target_link_libraries(${TEST_NAME} ${Boost_UNIT_TEST_FRAMEWORK_LIBRARY})
-    target_include_directories(${TEST_NAME} PRIVATE ${Boost_INCLUDE_DIRS})
-    add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME} WORKING_DIRECTORY ${PROJECT_BINARY_DIR})
+    target_link_libraries(${TEST_NAME} ${Boost_UNIT_TEST_FRAMEWORK_LIBRARY} toml11::toml11)
+    target_include_directories(${TEST_NAME} SYSTEM PRIVATE ${Boost_INCLUDE_DIRS})
+    target_compile_definitions(${TEST_NAME} PRIVATE "BOOST_TEST_MODULE=\"${TEST_NAME}\"")
 
-    # Set the PATH to be able to find Boost DLL
-    if(WIN32)
-        STRING(REPLACE ";" "\\;" PATH_STRING "$ENV{PATH}")
-        set_tests_properties(${TEST_NAME}
-            PROPERTIES ENVIRONMENT "PATH=${PATH_STRING}\;${Boost_LIBRARY_DIRS}"
-        )
+    # to compile tests with <filesystem>...
+    if(TOML11_REQUIRE_FILESYSTEM_LIBRARY)
+        if(TOML11_WITH_LIBCXX_LIBRARY)
+            target_link_libraries(${TEST_NAME} "c++fs")
+        else()
+            target_link_libraries(${TEST_NAME} "stdc++fs")
+        endif()
     endif()
+
+    target_include_directories(${TEST_NAME} PRIVATE ${Boost_INCLUDE_DIRS})
+
+    if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+        if(toml11_TEST_WITH_ASAN)
+            set_target_properties(${TEST_NAME} PROPERTIES
+                COMPILE_FLAGS "-fsanitize=address -fno-omit-frame-pointer"
+                LINK_FLAGS    "-fsanitize=address -fno-omit-frame-pointer")
+        elseif(toml11_TEST_WITH_UBSAN)
+            set_target_properties(${TEST_NAME} PROPERTIES
+                COMPILE_FLAGS "-fsanitize=undefined"
+                LINK_FLAGS    "-fsanitize=undefined")
+        endif()
+    endif()
+
+    add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
+    set_tests_properties(${TEST_NAME} PROPERTIES ENVIRONMENT "${TEST_ENVIRON}")
 endforeach(TEST_NAME)
+
+
+# this test is to check it compiles. it will not run
+add_executable(test_multiple_translation_unit
+               test_multiple_translation_unit_1.cpp
+               test_multiple_translation_unit_2.cpp)
+target_link_libraries(test_multiple_translation_unit toml11::toml11)
+
+if(WIN32)
+    add_executable(test_windows test_windows.cpp)
+    target_link_libraries(test_windows toml11::toml11)
+endif()
+

tests/check.cpp

@@ -0,0 +1,42 @@
+#include <toml.hpp>
+
+#include <iostream>
+#include <iomanip>
+
+int main(int argc, char **argv)
+{
+    if(argc != 3)
+    {
+        std::cerr << "usage: ./check [filename] [valid|invalid]" << std::endl;
+        return 1;
+    }
+
+    const std::string file_kind(argv[2]);
+
+    try
+    {
+        const auto data = toml::parse(argv[1]);
+        std::cout << std::setprecision(16) << std::setw(80) << data;
+        if(file_kind == "valid")
+        {
+            return 0;
+        }
+        else
+        {
+            return 1;
+        }
+    }
+    catch(const toml::syntax_error& err)
+    {
+        std::cout << "what(): " << err.what() << std::endl;
+        if(file_kind == "invalid")
+        {
+            return 0;
+        }
+        else
+        {
+            return 1;
+        }
+    }
+    return 127;
+}

tests/check_serialization.cpp

@@ -0,0 +1,114 @@
+#include <toml.hpp>
+
+#include <iomanip>
+#include <iostream>
+
+int main(int argc, char **argv)
+{
+    if(argc != 2)
+    {
+        std::cerr << "usage: ./check [filename]" << std::endl;
+        return 1;
+    }
+
+    const std::string filename(argv[1]);
+
+    {
+        const auto data = toml::parse(filename);
+        {
+            std::ofstream ofs("tmp.toml");
+            ofs << std::setprecision(16) << std::setw(80) << data;
+        }
+        const auto serialized = toml::parse("tmp.toml");
+
+        if(data != serialized)
+        {
+            // this is really a ditry hack, but is the easiest way...
+            // TODO: cleanup by adding comparison function to check if a value is NaN or not
+            if(filename.substr(filename.size() - 22, 22) == "float-inf-and-nan.toml" &&
+                std::isnan   (toml::find<double>(serialized, "nan"))           &&
+               !std::signbit (toml::find<double>(serialized, "nan"))           &&
+                std::isnan   (toml::find<double>(serialized, "nan_plus"))      &&
+               !std::signbit (toml::find<double>(serialized, "nan_plus"))      &&
+                std::isnan   (toml::find<double>(serialized, "nan_neg"))       &&
+                std::signbit (toml::find<double>(serialized, "nan_neg"))       &&
+               !std::isnan   (toml::find<double>(serialized, "infinity"))      &&
+               !std::isfinite(toml::find<double>(serialized, "infinity"))      &&
+               !std::signbit (toml::find<double>(serialized, "infinity"))      &&
+               !std::isnan   (toml::find<double>(serialized, "infinity_plus")) &&
+               !std::isfinite(toml::find<double>(serialized, "infinity_plus")) &&
+               !std::signbit (toml::find<double>(serialized, "infinity_plus")) &&
+               !std::isnan   (toml::find<double>(serialized, "infinity_neg"))  &&
+               !std::isfinite(toml::find<double>(serialized, "infinity_neg"))  &&
+                std::signbit (toml::find<double>(serialized, "infinity_neg")))
+            {
+                // then it is correctly serialized.
+                // Note that, the result of (nan == nan) is false. so `data == serialized` is false.
+            }
+            else
+            {
+                std::cerr << "============================================================\n";
+                std::cerr << "result (w/o comment) different: " << filename << std::endl;
+                std::cerr << "------------------------------------------------------------\n";
+                std::cerr << "# serialized\n";
+                std::cerr << serialized;
+                std::cerr << "------------------------------------------------------------\n";
+                std::cerr << "# data\n";
+                std::cerr << data;
+                return 1;
+            }
+        }
+    }
+    {
+        const auto data = toml::parse<toml::preserve_comments>(filename);
+        {
+            std::ofstream ofs("tmp.toml");
+            ofs << std::setprecision(16) << std::setw(80) << data;
+        }
+        const auto serialized = toml::parse<toml::preserve_comments>("tmp.toml");
+        if(data != serialized)
+        {
+            // this is really a ditry hack, but is the easiest way...
+            // TODO: cleanup by adding comparison function to check if a value is NaN or not
+            if(filename.substr(filename.size() - 22, 22) == "float-inf-and-nan.toml" &&
+                std::isnan   (toml::find<double>(serialized, "nan"))           &&
+               !std::signbit (toml::find<double>(serialized, "nan"))           &&
+                std::isnan   (toml::find<double>(serialized, "nan_plus"))      &&
+               !std::signbit (toml::find<double>(serialized, "nan_plus"))      &&
+                std::isnan   (toml::find<double>(serialized, "nan_neg"))       &&
+                std::signbit (toml::find<double>(serialized, "nan_neg"))       &&
+               !std::isnan   (toml::find<double>(serialized, "infinity"))      &&
+               !std::isfinite(toml::find<double>(serialized, "infinity"))      &&
+               !std::signbit (toml::find<double>(serialized, "infinity"))      &&
+               !std::isnan   (toml::find<double>(serialized, "infinity_plus")) &&
+               !std::isfinite(toml::find<double>(serialized, "infinity_plus")) &&
+               !std::signbit (toml::find<double>(serialized, "infinity_plus")) &&
+               !std::isnan   (toml::find<double>(serialized, "infinity_neg"))  &&
+               !std::isfinite(toml::find<double>(serialized, "infinity_neg"))  &&
+                std::signbit (toml::find<double>(serialized, "infinity_neg"))  &&
+                toml::find(data, "nan").comments()           == toml::find(serialized, "nan").comments()           &&
+                toml::find(data, "nan_plus").comments()      == toml::find(serialized, "nan_plus").comments()      &&
+                toml::find(data, "nan_neg").comments()       == toml::find(serialized, "nan_neg").comments()       &&
+                toml::find(data, "infinity").comments()      == toml::find(serialized, "infinity").comments()      &&
+                toml::find(data, "infinity_plus").comments() == toml::find(serialized, "infinity_plus").comments() &&
+                toml::find(data, "infinity_neg").comments()  == toml::find(serialized, "infinity_neg").comments()  )
+            {
+                // then it is correctly serialized.
+                // Note that, the result of (nan == nan) is false. so `data == serialized` is false.
+            }
+            else
+            {
+                std::cerr << "============================================================\n";
+                std::cerr << "result (w/  comment) different: " << filename << std::endl;
+                std::cerr << "------------------------------------------------------------\n";
+                std::cerr << "# serialized\n";
+                std::cerr << serialized;
+                std::cerr << "------------------------------------------------------------\n";
+                std::cerr << "# data\n";
+                std::cerr << data;
+                return 1;
+            }
+        }
+    }
+    return 0;
+}

tests/check_toml_test.cpp

@@ -0,0 +1,139 @@
+#include <toml.hpp>
+
+#include <iomanip>
+#include <iostream>
+
+struct json_serializer
+{
+    void operator()(toml::boolean v)
+    {
+        std::cout << "{\"type\":\"bool\",\"value\":\"" << toml::value(v) << "\"}";
+        return ;
+    }
+    void operator()(toml::integer v)
+    {
+        std::cout << "{\"type\":\"integer\",\"value\":\"" << toml::value(v) << "\"}";
+        return ;
+    }
+    void operator()(toml::floating v)
+    {
+        if(std::isnan(v) && std::signbit(v))
+        {
+            // toml-test does not allow negative NaN represented in "-nan" because
+            // there are languages that does not distinguish nan and -nan.
+            // But toml11 keeps sign from input. To resolve this difference,
+            // we convert -nan to nan here.
+            v = std::numeric_limits<toml::floating>::quiet_NaN();
+        }
+        std::cout << "{\"type\":\"float\",\"value\":\"" << toml::value(v) << "\"}";
+        return ;
+    }
+    void operator()(const toml::string& v)
+    {
+        // since toml11 automatically convert string to multiline string that is
+        // valid only in TOML, we need to format the string to make it valid in
+        // JSON.
+        toml::serializer<toml::value> ser(std::numeric_limits<std::size_t>::max());
+        std::cout << "{\"type\":\"string\",\"value\":"
+                  << ser(v.str) << "}";
+        return ;
+    }
+    void operator()(const toml::local_time& v)
+    {
+        std::cout << "{\"type\":\"time-local\",\"value\":\"" << toml::value(v) << "\"}";
+        return ;
+    }
+    void operator()(const toml::local_date& v)
+    {
+        std::cout << "{\"type\":\"date-local\",\"value\":\"" << toml::value(v) << "\"}";
+        return ;
+    }
+    void operator()(const toml::local_datetime& v)
+    {
+        std::cout << "{\"type\":\"datetime-local\",\"value\":\"" << toml::value(v) << "\"}";
+        return ;
+    }
+    void operator()(const toml::offset_datetime& v)
+    {
+        std::cout << "{\"type\":\"datetime\",\"value\":\"" << toml::value(v) << "\"}";
+        return ;
+    }
+    void operator()(const toml::array& v)
+    {
+        if(!v.empty() && v.front().is_table())
+        {
+            std::cout << '[';
+            bool is_first = true;
+            for(const auto& elem : v)
+            {
+                if(!is_first) {std::cout << ", ";}
+                is_first = false;
+                toml::visit(*this, elem);
+            }
+            std::cout << ']';
+        }
+        else
+        {
+//             std::cout << "{\"type\":\"array\",\"value\":[";
+            std::cout << "[";
+            bool is_first = true;
+            for(const auto& elem : v)
+            {
+                if(!is_first) {std::cout << ", ";}
+                is_first = false;
+                toml::visit(*this, elem);
+            }
+            std::cout << "]";
+        }
+        return ;
+    }
+    void operator()(const toml::table& v)
+    {
+        std::cout << '{';
+        bool is_first = true;
+        for(const auto& elem : v)
+        {
+            if(!is_first) {std::cout << ", ";}
+            is_first = false;
+            const auto k = toml::format_key(elem.first);
+            if(k.at(0) == '"')
+            {
+                std::cout << k << ":";
+            }
+            else // bare key
+            {
+                std::cout << '\"' << k << "\":";
+            }
+            toml::visit(*this, elem.second);
+        }
+        std::cout << '}';
+        return ;
+    }
+};
+
+int main()
+{
+    try
+    {
+        std::vector<char> buf;
+        std::cin.peek();
+        while(!std::cin.eof())
+        {
+            buf.push_back(std::cin.get());
+            std::cin.peek();
+        }
+        std::string bufstr(buf.begin(), buf.end());
+
+        std::istringstream ss(bufstr);
+
+        const auto data = toml::parse(ss);
+        std::cout << std::setprecision(std::numeric_limits<double>::max_digits10);
+        toml::visit(json_serializer(), data);
+        return 0;
+    }
+    catch(const toml::syntax_error& err)
+    {
+        std::cout << "what(): " << err.what() << std::endl;
+        return 1;
+    }
+}

tests/test_comments.cpp

@@ -0,0 +1,545 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+BOOST_AUTO_TEST_CASE(test_comment_before)
+{
+    {
+        const std::string file = R"(
+            # comment for a.
+            a = 42
+            # comment for b.
+            b = "baz"
+        )";
+        std::istringstream iss(file);
+        const auto v = toml::parse<toml::preserve_comments>(iss);
+
+        const auto a = toml::find(v, "a");
+        const auto b = toml::find(v, "b");
+
+        BOOST_TEST(a.comments().size()  == 1u);
+        BOOST_TEST(a.comments().front() == " comment for a.");
+        BOOST_TEST(b.comments().size()  == 1u);
+        BOOST_TEST(b.comments().front() == " comment for b.");
+    }
+    {
+        const std::string file = R"(
+            # comment for a.
+            # another comment for a.
+            a = 42
+            # comment for b.
+            # also comment for b.
+            b = "baz"
+        )";
+
+        std::istringstream iss(file);
+        const auto v = toml::parse<toml::preserve_comments>(iss);
+
+        const auto a = toml::find(v, "a");
+        const auto b = toml::find(v, "b");
+
+        BOOST_TEST(a.comments().size()  == 2u);
+        BOOST_TEST(a.comments().front() == " comment for a.");
+        BOOST_TEST(a.comments().back()  == " another comment for a.");
+        BOOST_TEST(b.comments().size()  == 2u);
+        BOOST_TEST(b.comments().front() == " comment for b.");
+        BOOST_TEST(b.comments().back()  == " also comment for b.");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_comment_inline)
+{
+    {
+        const std::string file = R"(
+            a = 42    # comment for a.
+            b = "baz" # comment for b.
+        )";
+
+        std::istringstream iss(file);
+        const auto v = toml::parse<toml::preserve_comments>(iss);
+
+        const auto a = toml::find(v, "a");
+        const auto b = toml::find(v, "b");
+
+        BOOST_TEST(a.comments().size()  == 1u);
+        BOOST_TEST(a.comments().front() == " comment for a.");
+        BOOST_TEST(b.comments().size()  == 1u);
+        BOOST_TEST(b.comments().front() == " comment for b.");
+    }
+    {
+        const std::string file = R"(
+            a = [
+                42,
+            ] # comment for a.
+            b = [
+                "bar", # this is not a comment for b, but "bar"
+            ] # this is a comment for b.
+        )";
+
+        std::istringstream iss(file);
+        const auto v = toml::parse<toml::preserve_comments>(iss);
+
+        const auto a  = toml::find(v, "a");
+        const auto b  = toml::find(v, "b");
+        const auto b0 = b.as_array().at(0);
+
+        BOOST_TEST(a.comments().size()   == 1u);
+        BOOST_TEST(a.comments().front()  == " comment for a.");
+        BOOST_TEST(b.comments().size()   == 1u);
+        BOOST_TEST(b.comments().front()  == " this is a comment for b.");
+        BOOST_TEST(b0.comments().size()  == 1u);
+        BOOST_TEST(b0.comments().front() == " this is not a comment for b, but \"bar\"");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_comment_both)
+{
+    {
+        const std::string file = R"(
+            # comment for a.
+            a = 42 # inline comment for a.
+            # comment for b.
+            b = "baz" # inline comment for b.
+            # comment for c.
+            c = [ # this comment will be ignored
+                # comment for the first element.
+                10 # this also.
+            ] # another comment for c.
+        )";
+
+        std::istringstream iss(file);
+        const auto v = toml::parse<toml::preserve_comments>(iss);
+
+        const auto a  = toml::find(v, "a");
+        const auto b  = toml::find(v, "b");
+        const auto c  = toml::find(v, "c");
+        const auto c0 = c.as_array().at(0);
+
+        BOOST_TEST(a.comments().size()  == 2u);
+        BOOST_TEST(a.comments().front() == " comment for a.");
+        BOOST_TEST(a.comments().back()  == " inline comment for a.");
+        BOOST_TEST(b.comments().size()  == 2u);
+        BOOST_TEST(b.comments().front() == " comment for b.");
+        BOOST_TEST(b.comments().back()  == " inline comment for b.");
+
+        BOOST_TEST(c.comments().size()  == 2u);
+        BOOST_TEST(c.comments().front() == " comment for c.");
+        BOOST_TEST(c.comments().back()  == " another comment for c.");
+
+        BOOST_TEST(c0.comments().size()  == 2u);
+        BOOST_TEST(c0.comments().front() == " comment for the first element.");
+        BOOST_TEST(c0.comments().back()  == " this also.");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_comments_on_implicit_values)
+{
+    {
+        const std::string file = R"(
+            # comment for the first element of array-of-tables.
+            [[array-of-tables]]
+            foo = "bar"
+        )";
+        std::istringstream iss(file);
+        const auto v = toml::parse<toml::preserve_comments>(iss);
+
+        const auto aot = toml::find(v, "array-of-tables");
+        const auto elm = aot.at(0);
+        BOOST_TEST(aot.comments().empty());
+        BOOST_TEST(elm.comments().size() == 1);
+        BOOST_TEST(elm.comments().front() == " comment for the first element of array-of-tables.");
+    }
+    {
+        const std::string file = R"(
+            # comment for the array itself
+            array-of-tables = [
+                # comment for the first element of array-of-tables.
+                {foo = "bar"}
+            ]
+        )";
+        std::istringstream iss(file);
+        const auto v = toml::parse<toml::preserve_comments>(iss);
+
+        const auto aot = toml::find(v, "array-of-tables");
+        const auto elm = aot.at(0);
+        BOOST_TEST(aot.comments().size() == 1);
+        BOOST_TEST(aot.comments().front() == " comment for the array itself");
+        BOOST_TEST(elm.comments().size() == 1);
+        BOOST_TEST(elm.comments().front() == " comment for the first element of array-of-tables.");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_discard_comment)
+{
+    const std::string file = R"(
+        # comment for a.
+        a = 42 # inline comment for a.
+        # comment for b.
+        b = "baz" # inline comment for b.
+        # comment for c.
+        c = [ # this comment will be ignored
+            # comment for the first element.
+            10 # this also.
+        ] # another comment for c.
+    )";
+
+    std::istringstream iss(file);
+    const auto v = toml::parse<toml::discard_comments>(iss);
+
+    const auto a  = toml::find(v, "a");
+    const auto b  = toml::find(v, "b");
+    const auto c  = toml::find(v, "c");
+    const auto c0 = c.as_array().at(0);
+
+    BOOST_TEST(a.comments().empty());
+    BOOST_TEST(b.comments().empty());
+    BOOST_TEST(c.comments().empty());
+    BOOST_TEST(c0.comments().empty());
+}
+
+BOOST_AUTO_TEST_CASE(test_construct_value_with_comments)
+{
+    using value_type = toml::basic_value<toml::preserve_comments>;
+    {
+        const value_type v(true, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_boolean());
+        BOOST_TEST(v.as_boolean() == true);
+    }
+    {
+        const value_type v(42, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_integer());
+        BOOST_TEST(v.as_integer() == 42);
+    }
+    {
+        const value_type v(3.14, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_floating());
+        BOOST_TEST(v.as_floating() == 3.14);
+    }
+    {
+        const value_type v(toml::string("str"), {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_string());
+        BOOST_TEST(v.as_string() == "str");
+    }
+    {
+        const value_type v(std::string("str"), {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_string());
+        BOOST_TEST(v.as_string() == "str");
+    }
+    {
+        const value_type v(std::string("str"), toml::string_t::literal,
+                           {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_string());
+        BOOST_TEST(v.as_string() == "str");
+    }
+    {
+        const value_type v("str", {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_string());
+        BOOST_TEST(v.as_string() == "str");
+    }
+    {
+        const value_type v("str", toml::string_t::literal,
+                           {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_string());
+        BOOST_TEST(v.as_string() == "str");
+    }
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+    {
+        using namespace std::literals::string_view_literals;
+        const value_type v("str"sv, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_string());
+        BOOST_TEST(v.as_string() == "str");
+    }
+    {
+        using namespace std::literals::string_view_literals;
+        const value_type v("str"sv, toml::string_t::literal,
+                           {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_string());
+        BOOST_TEST(v.as_string() == "str");
+    }
+#endif
+    const toml::local_date      ld{2019, toml::month_t::Apr, 1};
+    const toml::local_time      lt{12, 30, 45};
+    const toml::local_datetime  ldt{ld, lt};
+    const toml::offset_datetime odt{ld, lt, toml::time_offset{9, 0}};
+    {
+        const value_type v(ld, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_local_date());
+        BOOST_TEST(v.as_local_date() == ld);
+    }
+    {
+        const value_type v(lt, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_local_time());
+        BOOST_TEST(v.as_local_time() == lt);
+    }
+    {
+        const toml::local_time three_hours{3,0,0};
+        const value_type v(std::chrono::hours(3), {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_local_time());
+        BOOST_TEST(v.as_local_time() == three_hours);
+    }
+    {
+        const value_type v(ldt, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_local_datetime());
+        BOOST_TEST(v.as_local_datetime() == ldt);
+    }
+    {
+        const value_type v(odt, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_offset_datetime());
+        BOOST_TEST(v.as_offset_datetime() == odt);
+    }
+    {
+        const auto systp = static_cast<std::chrono::system_clock::time_point>(odt);
+        const value_type v(systp, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_offset_datetime());
+
+        // While the conversion, the information about time offset may change.
+        const auto systp2 = static_cast<std::chrono::system_clock::time_point>(
+                v.as_offset_datetime());
+        const bool result = systp == systp2; // because there is no operator<<
+        BOOST_TEST(result);
+    }
+    {
+        const typename value_type::array_type a{1,2,3,4,5};
+        const value_type v(a, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_array());
+        BOOST_TEST(v.as_array().at(0).is_integer());
+        BOOST_TEST(v.as_array().at(1).is_integer());
+        BOOST_TEST(v.as_array().at(2).is_integer());
+        BOOST_TEST(v.as_array().at(3).is_integer());
+        BOOST_TEST(v.as_array().at(4).is_integer());
+        BOOST_TEST(v.as_array().at(0).as_integer() == 1);
+        BOOST_TEST(v.as_array().at(1).as_integer() == 2);
+        BOOST_TEST(v.as_array().at(2).as_integer() == 3);
+        BOOST_TEST(v.as_array().at(3).as_integer() == 4);
+        BOOST_TEST(v.as_array().at(4).as_integer() == 5);
+    }
+    {
+        const std::initializer_list<int> a = {1,2,3,4,5};
+        const value_type v(a, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_array());
+        BOOST_TEST(v.as_array().at(0).is_integer());
+        BOOST_TEST(v.as_array().at(1).is_integer());
+        BOOST_TEST(v.as_array().at(2).is_integer());
+        BOOST_TEST(v.as_array().at(3).is_integer());
+        BOOST_TEST(v.as_array().at(4).is_integer());
+        BOOST_TEST(v.as_array().at(0).as_integer() == 1);
+        BOOST_TEST(v.as_array().at(1).as_integer() == 2);
+        BOOST_TEST(v.as_array().at(2).as_integer() == 3);
+        BOOST_TEST(v.as_array().at(3).as_integer() == 4);
+        BOOST_TEST(v.as_array().at(4).as_integer() == 5);
+    }
+    {
+        const std::vector<int> a = {1,2,3,4,5};
+        const value_type v(a, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_array());
+        BOOST_TEST(v.as_array().at(0).is_integer());
+        BOOST_TEST(v.as_array().at(1).is_integer());
+        BOOST_TEST(v.as_array().at(2).is_integer());
+        BOOST_TEST(v.as_array().at(3).is_integer());
+        BOOST_TEST(v.as_array().at(4).is_integer());
+        BOOST_TEST(v.as_array().at(0).as_integer() == 1);
+        BOOST_TEST(v.as_array().at(1).as_integer() == 2);
+        BOOST_TEST(v.as_array().at(2).as_integer() == 3);
+        BOOST_TEST(v.as_array().at(3).as_integer() == 4);
+        BOOST_TEST(v.as_array().at(4).as_integer() == 5);
+    }
+    {
+        const typename value_type::table_type t{
+                {"key1", 42}, {"key2", "foobar"}
+            };
+        const value_type v(t, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_table());
+        BOOST_TEST(v.as_table().at("key1").is_integer());
+        BOOST_TEST(v.as_table().at("key1").as_integer() == 42);
+        BOOST_TEST(v.as_table().at("key2").is_string());
+        BOOST_TEST(v.as_table().at("key2").as_string() == "foobar");
+    }
+    {
+        const std::initializer_list<std::pair<std::string, value_type>> t{
+                {"key1", 42}, {"key2", "foobar"}
+            };
+        const value_type v(t, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_table());
+        BOOST_TEST(v.as_table().at("key1").is_integer());
+        BOOST_TEST(v.as_table().at("key1").as_integer() == 42);
+        BOOST_TEST(v.as_table().at("key2").is_string());
+        BOOST_TEST(v.as_table().at("key2").as_string() == "foobar");
+    }
+    {
+        const std::map<std::string, value_type> t{
+                {"key1", 42}, {"key2", "foobar"}
+            };
+        const value_type v(t, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_table());
+        BOOST_TEST(v.as_table().at("key1").is_integer());
+        BOOST_TEST(v.as_table().at("key1").as_integer() == 42);
+        BOOST_TEST(v.as_table().at("key2").is_string());
+        BOOST_TEST(v.as_table().at("key2").as_string() == "foobar");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_overwrite_comments)
+{
+    using value_type = toml::basic_value<toml::preserve_comments>;
+    {
+        const value_type v(42, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_integer());
+        BOOST_TEST(v.as_integer() == 42);
+
+        const value_type u(v, {"comment3", "comment4"});
+        BOOST_TEST(u.comments().size() == 2u);
+        BOOST_TEST(u.comments().at(0)  == "comment3");
+        BOOST_TEST(u.comments().at(1)  == "comment4");
+        BOOST_TEST(u.is_integer());
+        BOOST_TEST(u.as_integer() == 42);
+    }
+    {
+        const value_type v(42, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_integer());
+        BOOST_TEST(v.as_integer() == 42);
+
+        const value_type u(v);
+        BOOST_TEST(u.comments().size() == 2u);
+        BOOST_TEST(u.comments().at(0)  == "comment1");
+        BOOST_TEST(u.comments().at(1)  == "comment2");
+        BOOST_TEST(u.is_integer());
+        BOOST_TEST(u.as_integer() == 42);
+    }
+    {
+        const value_type v(42, {"comment1", "comment2"});
+        BOOST_TEST(v.comments().size() == 2u);
+        BOOST_TEST(v.comments().at(0)  == "comment1");
+        BOOST_TEST(v.comments().at(1)  == "comment2");
+        BOOST_TEST(v.is_integer());
+        BOOST_TEST(v.as_integer() == 42);
+
+        const value_type u(v, {});
+        BOOST_TEST(u.comments().size() == 0u);
+        BOOST_TEST(u.is_integer());
+        BOOST_TEST(u.as_integer() == 42);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_output_comments)
+{
+    using value_type = toml::basic_value<toml::preserve_comments>;
+    {
+        const value_type v(42, {"comment1", "comment2"});
+        std::ostringstream oss;
+        oss << v.comments();
+
+        std::ostringstream ref;
+        ref << "#comment1\n";
+        ref << "#comment2\n";
+
+        BOOST_TEST(oss.str() == ref.str());
+    }
+    {
+        const value_type v(42, {"comment1", "comment2"});
+        std::ostringstream oss;
+
+        // If v is not a table, toml11 assumes that user is writing something
+        // like the following.
+
+        oss << "answer = " << v;
+
+        BOOST_TEST(oss.str() == "answer = 42 #comment1comment2");
+    }
+
+    {
+        const value_type v(42, {"comment1", "comment2"});
+        std::ostringstream oss;
+
+        // If v is not a table, toml11 assumes that user is writing something
+        // like the following.
+
+        oss << toml::nocomment << "answer = " << v;
+
+        BOOST_TEST(oss.str() == "answer = 42");
+    }
+
+    {
+        const value_type v(42, {"comment1", "comment2"});
+        std::ostringstream oss;
+
+        // If v is not a table, toml11 assumes that user is writing something
+        // like the following.
+
+        oss << toml::nocomment << toml::showcomment << "answer = " << v;
+
+        BOOST_TEST(oss.str() == "answer = 42 #comment1comment2");
+    }
+
+}

tests/test_datetime.cpp

@@ -1,57 +1,52 @@
-#define BOOST_TEST_MODULE "test_datetime"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/datetime.hpp>
 
+#include "unit_test.hpp"
+
 BOOST_AUTO_TEST_CASE(test_local_date)
 {
     const toml::local_date date(2018, toml::month_t::Jan, 1);
     const toml::local_date date1(date);
-    BOOST_CHECK_EQUAL(date, date1);
+    BOOST_TEST(date == date1);
 
     const std::chrono::system_clock::time_point tp(date);
     const toml::local_date date2(tp);
-    BOOST_CHECK_EQUAL(date, date2);
+    BOOST_TEST(date == date2);
 
     const toml::local_date date3(2017, toml::month_t::Dec, 31);
-    BOOST_CHECK(date > date3);
+    BOOST_TEST(date > date3);
 
     std::ostringstream oss;
     oss << date;
-    BOOST_CHECK_EQUAL(oss.str(), std::string("2018-01-01"));
+    BOOST_TEST(oss.str() == std::string("2018-01-01"));
 }
 
 BOOST_AUTO_TEST_CASE(test_local_time)
 {
     const toml::local_time time(12, 30, 45);
     const toml::local_time time1(time);
-    BOOST_CHECK_EQUAL(time, time1);
+    BOOST_TEST(time == time1);
 
     const std::chrono::nanoseconds dur(time);
     std::chrono::nanoseconds ns(0);
     ns += std::chrono::hours  (12);
     ns += std::chrono::minutes(30);
     ns += std::chrono::seconds(45);
-    BOOST_CHECK_EQUAL(dur.count(), ns.count());
+    BOOST_TEST(dur.count() == ns.count());
 
     const toml::local_time time3(12, 15, 45);
-    BOOST_CHECK(time > time3);
+    BOOST_TEST(time > time3);
 
     {
         std::ostringstream oss;
         oss << time;
-        BOOST_CHECK_EQUAL(oss.str(), std::string("12:30:45"));
+        BOOST_TEST(oss.str() == std::string("12:30:45"));
     }
 
     {
         const toml::local_time time4(12, 30, 45, 123, 456);
         std::ostringstream oss;
         oss << time4;
-        BOOST_CHECK_EQUAL(oss.str(), std::string("12:30:45.123456"));
+        BOOST_TEST(oss.str() == std::string("12:30:45.123456"));
     }
 }
 
@@ -59,20 +54,20 @@ BOOST_AUTO_TEST_CASE(test_time_offset)
 {
     const toml::time_offset time(9, 30);
     const toml::time_offset time1(time);
-    BOOST_CHECK_EQUAL(time, time1);
+    BOOST_TEST(time == time1);
 
     const std::chrono::minutes dur(time);
     std::chrono::minutes m(0);
     m += std::chrono::hours  (9);
     m += std::chrono::minutes(30);
-    BOOST_CHECK_EQUAL(dur.count(), m.count());
+    BOOST_TEST(dur.count() == m.count());
 
     const toml::time_offset time2(9, 0);
-    BOOST_CHECK(time2 < time);
+    BOOST_TEST(time2 < time);
 
     std::ostringstream oss;
     oss << time;
-    BOOST_CHECK_EQUAL(oss.str(), std::string("+09:30"));
+    BOOST_TEST(oss.str() == std::string("+09:30"));
 }
 
 BOOST_AUTO_TEST_CASE(test_local_datetime)
@@ -80,15 +75,15 @@ BOOST_AUTO_TEST_CASE(test_local_datetime)
     const toml::local_datetime dt(toml::local_date(2018, toml::month_t::Jan, 1),
                                   toml::local_time(12, 30, 45));
     const toml::local_datetime dt1(dt);
-    BOOST_CHECK_EQUAL(dt, dt1);
+    BOOST_TEST(dt == dt1);
 
     const std::chrono::system_clock::time_point tp(dt);
     const toml::local_datetime dt2(tp);
-    BOOST_CHECK_EQUAL(dt, dt2);
+    BOOST_TEST(dt == dt2);
 
     std::ostringstream oss;
     oss << dt;
-    BOOST_CHECK_EQUAL(oss.str(), std::string("2018-01-01T12:30:45"));
+    BOOST_TEST(oss.str() == std::string("2018-01-01T12:30:45"));
 }
 
 BOOST_AUTO_TEST_CASE(test_offset_datetime)
@@ -97,17 +92,18 @@ BOOST_AUTO_TEST_CASE(test_offset_datetime)
                                    toml::local_time(12, 30, 45),
                                    toml::time_offset(9, 30));
     const toml::offset_datetime dt1(dt);
-    BOOST_CHECK_EQUAL(dt, dt1);
+    BOOST_TEST(dt == dt1);
 
     const std::chrono::system_clock::time_point tp1(dt);
     const toml::offset_datetime dt2(tp1);
     const std::chrono::system_clock::time_point tp2(dt2);
-    BOOST_CHECK(tp1 == tp2);
+    const bool tp_same = (tp1 == tp2);
+    BOOST_TEST(tp_same);
 
     {
         std::ostringstream oss;
         oss << dt;
-        BOOST_CHECK_EQUAL(oss.str(), std::string("2018-01-01T12:30:45+09:30"));
+        BOOST_TEST(oss.str() == std::string("2018-01-01T12:30:45+09:30"));
     }
     {
         const toml::offset_datetime dt3(
@@ -116,6 +112,6 @@ BOOST_AUTO_TEST_CASE(test_offset_datetime)
                 toml::time_offset(0, 0));
         std::ostringstream oss;
         oss << dt3;
-        BOOST_CHECK_EQUAL(oss.str(), std::string("2018-01-01T12:30:45Z"));
+        BOOST_TEST(oss.str() == std::string("2018-01-01T12:30:45Z"));
     }
 }

tests/test_error_detection.cpp

@@ -1,61 +1,26 @@
-#define BOOST_TEST_MODULE "test_error_detection"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
-#include <iostream>
+
+#include "unit_test.hpp"
+
 #include <fstream>
+#include <iostream>
 
 BOOST_AUTO_TEST_CASE(test_detect_empty_key)
 {
     std::istringstream stream(std::string("= \"value\""));
-    bool exception_thrown = false;
-    try
-    {
-        toml::parse(stream, "test_detect_empty_key");
-    }
-    catch(const toml::syntax_error& syn)
-    {
-        // to see the error message
-        std::cerr << syn.what() << std::endl;
-        exception_thrown = true;
-    }
-    BOOST_CHECK(exception_thrown);
+    BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
 }
 
 BOOST_AUTO_TEST_CASE(test_detect_missing_value)
 {
     std::istringstream stream(std::string("a ="));
-    bool exception_thrown = false;
-    try
-    {
-        toml::parse(stream, "test_detect_missing_value");
-    }
-    catch(const toml::syntax_error& syn)
-    {
-        std::cerr << syn.what() << std::endl;
-        exception_thrown = true;
-    }
-    BOOST_CHECK(exception_thrown);
+    BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
 }
 
 BOOST_AUTO_TEST_CASE(test_detect_too_many_value)
 {
     std::istringstream stream(std::string("a = 1 = \"value\""));
-    bool exception_thrown = false;
-    try
-    {
-        toml::parse(stream, "test_detect_too_many_value");
-    }
-    catch(const toml::syntax_error& syn)
-    {
-        std::cerr << syn.what() << std::endl;
-        exception_thrown = true;
-    }
-    BOOST_CHECK(exception_thrown);
+    BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
 }
 
 BOOST_AUTO_TEST_CASE(test_detect_duplicate_table)
@@ -66,17 +31,7 @@ BOOST_AUTO_TEST_CASE(test_detect_duplicate_table)
             "[table]\n"
             "b = 42\n"
             ));
-    bool exception_thrown = false;
-    try
-    {
-        toml::parse(stream, "test_detect_duplicate_table");
-    }
-    catch(const toml::syntax_error& syn)
-    {
-        std::cerr << syn.what() << std::endl;
-        exception_thrown = true;
-    }
-    BOOST_CHECK(exception_thrown);
+    BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
 }
 
 BOOST_AUTO_TEST_CASE(test_detect_conflict_array_table)
@@ -87,17 +42,7 @@ BOOST_AUTO_TEST_CASE(test_detect_conflict_array_table)
             "[table]\n"
             "b = 42\n"
             ));
-    bool exception_thrown = false;
-    try
-    {
-        toml::parse(stream, "test_detect_conflict_array_table");
-    }
-    catch(const toml::syntax_error& syn)
-    {
-        std::cerr << syn.what() << std::endl;
-        exception_thrown = true;
-    }
-    BOOST_CHECK(exception_thrown);
+    BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
 }
 
 BOOST_AUTO_TEST_CASE(test_detect_conflict_table_array)
@@ -108,17 +53,7 @@ BOOST_AUTO_TEST_CASE(test_detect_conflict_table_array)
             "[[table]]\n"
             "b = 42\n"
             ));
-    bool exception_thrown = false;
-    try
-    {
-        toml::parse(stream, "test_detect_conflict_table_array");
-    }
-    catch(const toml::syntax_error& syn)
-    {
-        std::cerr << syn.what() << std::endl;
-        exception_thrown = true;
-    }
-    BOOST_CHECK(exception_thrown);
+    BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
 }
 
 BOOST_AUTO_TEST_CASE(test_detect_duplicate_value)
@@ -127,17 +62,7 @@ BOOST_AUTO_TEST_CASE(test_detect_duplicate_value)
             "a = 1\n"
             "a = 2\n"
             ));
-    bool exception_thrown = false;
-    try
-    {
-        toml::parse(stream, "test_detect_duplicate_value");
-    }
-    catch(const toml::syntax_error& syn)
-    {
-        std::cerr << syn.what() << std::endl;
-        exception_thrown = true;
-    }
-    BOOST_CHECK(exception_thrown);
+    BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
 }
 
 BOOST_AUTO_TEST_CASE(test_detect_conflicting_value)
@@ -146,35 +71,19 @@ BOOST_AUTO_TEST_CASE(test_detect_conflicting_value)
             "a.b   = 1\n"
             "a.b.c = 2\n"
             ));
-    bool exception_thrown = false;
-    try
-    {
-        toml::parse(stream, "test_detect_conflicting_value");
-    }
-    catch(const toml::syntax_error& syn)
-    {
-        std::cerr << syn.what() << std::endl;
-        exception_thrown = true;
-    }
-    BOOST_CHECK(exception_thrown);
+    BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
 }
 
 BOOST_AUTO_TEST_CASE(test_detect_inhomogeneous_array)
 {
+#ifdef TOML11_DISALLOW_HETEROGENEOUS_ARRAYS
     std::istringstream stream(std::string(
             "a = [1, 1.0]\n"
             ));
-    bool exception_thrown = false;
-    try
-    {
-        toml::parse(stream, "test_detect_inhomogeneous_array");
-    }
-    catch(const toml::syntax_error& syn)
-    {
-        std::cerr << syn.what() << std::endl;
-        exception_thrown = true;
-    }
-    BOOST_CHECK(exception_thrown);
+    BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
+#else
+    BOOST_TEST_MESSAGE("After v1.0.0-rc.1, heterogeneous arrays are allowed");
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_detect_appending_array_of_table)
@@ -184,16 +93,5 @@ BOOST_AUTO_TEST_CASE(test_detect_appending_array_of_table)
             "[[a]]\n"
             "b = 2\n"
             ));
-    bool exception_thrown = false;
-    try
-    {
-        toml::parse(stream, "test_detect_appending_array_of_table");
-    }
-    catch(const toml::syntax_error& syn)
-    {
-        std::cerr << syn.what() << std::endl;
-        exception_thrown = true;
-    }
-    BOOST_CHECK(exception_thrown);
+    BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
 }
-

tests/test_expect.cpp

@@ -0,0 +1,26 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+#include <array>
+#include <deque>
+#include <list>
+#include <map>
+#include <unordered_map>
+
+BOOST_AUTO_TEST_CASE(test_expect)
+{
+    {
+        toml::value v1(42);
+        toml::value v2(3.14);
+        const auto v1_or_0 = toml::expect<int>(v1).unwrap_or(0);
+        const auto v2_or_0 = toml::expect<int>(v2).unwrap_or(0);
+        BOOST_TEST(42 == v1_or_0);
+        BOOST_TEST( 0 == v2_or_0);
+
+        const auto v1_or_none = toml::expect<int>(v1).map([](int i){return std::to_string(i);}).unwrap_or(std::string("none"));
+        const auto v2_or_none = toml::expect<int>(v2).map([](int i){return std::to_string(i);}).unwrap_or(std::string("none"));
+        BOOST_TEST("42" ==   v1_or_none);
+        BOOST_TEST("none" == v2_or_none);
+    }
+}

tests/test_extended_conversions.cpp

@@ -0,0 +1,627 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+#include <deque>
+#include <map>
+
+namespace extlib
+{
+struct foo
+{
+    int a;
+    std::string b;
+};
+struct bar
+{
+    int a;
+    std::string b;
+
+    void from_toml(const toml::value& v)
+    {
+        this->a = toml::find<int>(v, "a");
+        this->b = toml::find<std::string>(v, "b");
+        return ;
+    }
+
+    toml::table into_toml() const
+    {
+        return toml::table{{"a", this->a}, {"b", this->b}};
+    }
+};
+
+struct baz
+{
+    int a;
+    std::string b;
+};
+struct qux
+{
+    int a;
+    std::string b;
+};
+
+struct foobar
+{
+    // via constructor
+    explicit foobar(const toml::value& v)
+        : a(toml::find<int>(v, "a")), b(toml::find<std::string>(v, "b"))
+    {}
+    int a;
+    std::string b;
+};
+} // extlib
+
+namespace toml
+{
+template<>
+struct from<extlib::foo>
+{
+    static extlib::foo from_toml(const toml::value& v)
+    {
+        return extlib::foo{toml::find<int>(v, "a"), toml::find<std::string>(v, "b")};
+    }
+};
+
+template<>
+struct into<extlib::foo>
+{
+    static toml::value into_toml(const extlib::foo& f)
+    {
+        return toml::value{{"a", f.a}, {"b", f.b}};
+    }
+};
+
+template<>
+struct from<extlib::baz>
+{
+    static extlib::baz from_toml(const toml::value& v)
+    {
+        return extlib::baz{toml::find<int>(v, "a"), toml::find<std::string>(v, "b")};
+    }
+};
+
+template<>
+struct into<extlib::qux>
+{
+    static toml::table into_toml(const extlib::qux& f)
+    {
+        return toml::table{{"a", f.a}, {"b", f.b}};
+    }
+};
+} // toml
+
+// ---------------------------------------------------------------------------
+
+namespace extlib2
+{
+struct foo
+{
+    int a;
+    std::string b;
+};
+struct bar
+{
+    int a;
+    std::string b;
+
+    template<typename C, template<typename ...> class M, template<typename ...> class A>
+    void from_toml(const toml::basic_value<C, M, A>& v)
+    {
+        this->a = toml::find<int>(v, "a");
+        this->b = toml::find<std::string>(v, "b");
+        return ;
+    }
+
+    toml::table into_toml() const
+    {
+        return toml::table{{"a", this->a}, {"b", this->b}};
+    }
+};
+struct baz
+{
+    int a;
+    std::string b;
+};
+struct qux
+{
+    int a;
+    std::string b;
+};
+
+struct foobar
+{
+    template<typename C, template<typename ...> class M, template<typename ...> class A>
+    explicit foobar(const toml::basic_value<C, M, A>& v)
+        : a(toml::find<int>(v, "a")), b(toml::find<std::string>(v, "b"))
+    {}
+    int a;
+    std::string b;
+};
+
+} // extlib2
+
+namespace toml
+{
+template<>
+struct from<extlib2::foo>
+{
+    template<typename C, template<typename ...> class M, template<typename ...> class A>
+    static extlib2::foo from_toml(const toml::basic_value<C, M, A>& v)
+    {
+        return extlib2::foo{toml::find<int>(v, "a"), toml::find<std::string>(v, "b")};
+    }
+};
+
+template<>
+struct into<extlib2::foo>
+{
+    static toml::table into_toml(const extlib2::foo& f)
+    {
+        return toml::table{{"a", f.a}, {"b", f.b}};
+    }
+};
+
+template<>
+struct from<extlib2::baz>
+{
+    template<typename C, template<typename ...> class M, template<typename ...> class A>
+    static extlib2::baz from_toml(const toml::basic_value<C, M, A>& v)
+    {
+        return extlib2::baz{toml::find<int>(v, "a"), toml::find<std::string>(v, "b")};
+    }
+};
+
+template<>
+struct into<extlib2::qux>
+{
+    static toml::basic_value<toml::preserve_comments, std::map>
+    into_toml(const extlib2::qux& f)
+    {
+        return toml::basic_value<toml::preserve_comments, std::map>{
+            {"a", f.a}, {"b", f.b}
+        };
+    }
+};
+} // toml
+
+// ---------------------------------------------------------------------------
+
+BOOST_AUTO_TEST_CASE(test_conversion_by_member_methods)
+{
+    {
+        const toml::value v{{"a", 42}, {"b", "baz"}};
+
+        const auto foo = toml::get<extlib::foo>(v);
+        BOOST_TEST(foo.a == 42);
+        BOOST_TEST(foo.b == "baz");
+
+        const toml::value v2(foo);
+
+        BOOST_TEST(v == v2);
+    }
+
+    {
+        const toml::value v{{"a", 42}, {"b", "baz"}};
+
+        const auto foo = toml::get<extlib2::foo>(v);
+        BOOST_TEST(foo.a == 42);
+        BOOST_TEST(foo.b == "baz");
+
+        const toml::value v2(foo);
+        BOOST_TEST(v == v2);
+    }
+
+    {
+        const toml::basic_value<toml::discard_comments, std::map, std::deque>
+            v{{"a", 42}, {"b", "baz"}};
+
+        const auto foo = toml::get<extlib2::foo>(v);
+        BOOST_TEST(foo.a == 42);
+        BOOST_TEST(foo.b == "baz");
+
+        const toml::basic_value<toml::discard_comments, std::map, std::deque>
+            v2(foo);
+
+        BOOST_TEST(v == v2);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_conversion_by_specialization)
+{
+    {
+        const toml::value v{{"a", 42}, {"b", "baz"}};
+
+        const auto bar = toml::get<extlib::bar>(v);
+        BOOST_TEST(bar.a == 42);
+        BOOST_TEST(bar.b == "baz");
+
+        const toml::value v2(bar);
+
+        BOOST_TEST(v == v2);
+    }
+    {
+        const toml::value v{{"a", 42}, {"b", "baz"}};
+
+        const auto bar = toml::get<extlib2::bar>(v);
+        BOOST_TEST(bar.a == 42);
+        BOOST_TEST(bar.b == "baz");
+
+        const toml::value v2(bar);
+
+        BOOST_TEST(v == v2);
+    }
+    {
+        const toml::basic_value<toml::discard_comments, std::map, std::deque>
+            v{{"a", 42}, {"b", "baz"}};
+
+        const auto bar = toml::get<extlib2::bar>(v);
+        BOOST_TEST(bar.a == 42);
+        BOOST_TEST(bar.b == "baz");
+
+        const toml::basic_value<toml::discard_comments, std::map, std::deque>
+            v2(bar);
+
+        BOOST_TEST(v == v2);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_conversion_one_way)
+{
+    {
+        const toml::value v{{"a", 42}, {"b", "baz"}};
+
+        const auto baz = toml::get<extlib::baz>(v);
+        BOOST_TEST(baz.a == 42);
+        BOOST_TEST(baz.b == "baz");
+    }
+    {
+        const extlib::qux q{42, "qux"};
+        const toml::value v(q);
+
+        BOOST_TEST(toml::find<int>(v, "a")         == 42);
+        BOOST_TEST(toml::find<std::string>(v, "b") == "qux");
+    }
+
+    {
+        const toml::basic_value<toml::discard_comments, std::map> v{
+            {"a", 42}, {"b", "baz"}
+        };
+
+        const auto baz = toml::get<extlib2::baz>(v);
+        BOOST_TEST(baz.a == 42);
+        BOOST_TEST(baz.b == "baz");
+    }
+    {
+        const extlib::qux q{42, "qux"};
+        const toml::basic_value<toml::preserve_comments, std::map> v(q);
+
+        BOOST_TEST(toml::find<int>(v, "a")         == 42);
+        BOOST_TEST(toml::find<std::string>(v, "b") == "qux");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_conversion_via_constructor)
+{
+    {
+        const toml::value v{{"a", 42}, {"b", "foobar"}};
+
+        const auto foobar = toml::get<extlib::foobar>(v);
+        BOOST_TEST(foobar.a == 42);
+        BOOST_TEST(foobar.b == "foobar");
+    }
+
+    {
+        const toml::basic_value<toml::discard_comments, std::map> v{
+            {"a", 42}, {"b", "foobar"}
+        };
+
+        const auto foobar = toml::get<extlib2::foobar>(v);
+        BOOST_TEST(foobar.a == 42);
+        BOOST_TEST(foobar.b == "foobar");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_recursive_conversion)
+{
+    {
+        const toml::value v{
+            toml::table{{"a", 42}, {"b", "baz"}},
+            toml::table{{"a", 43}, {"b", "qux"}},
+            toml::table{{"a", 44}, {"b", "quux"}},
+            toml::table{{"a", 45}, {"b", "foobar"}},
+        };
+
+        const auto foos = toml::get<std::vector<extlib::foo>>(v);
+        BOOST_TEST(foos.size()  == 4ul);
+        BOOST_TEST(foos.at(0).a == 42);
+        BOOST_TEST(foos.at(1).a == 43);
+        BOOST_TEST(foos.at(2).a == 44);
+        BOOST_TEST(foos.at(3).a == 45);
+
+        BOOST_TEST(foos.at(0).b == "baz");
+        BOOST_TEST(foos.at(1).b == "qux");
+        BOOST_TEST(foos.at(2).b == "quux");
+        BOOST_TEST(foos.at(3).b == "foobar");
+
+        const auto bars = toml::get<std::vector<extlib::bar>>(v);
+        BOOST_TEST(bars.size()  == 4ul);
+        BOOST_TEST(bars.at(0).a == 42);
+        BOOST_TEST(bars.at(1).a == 43);
+        BOOST_TEST(bars.at(2).a == 44);
+        BOOST_TEST(bars.at(3).a == 45);
+
+        BOOST_TEST(bars.at(0).b == "baz");
+        BOOST_TEST(bars.at(1).b == "qux");
+        BOOST_TEST(bars.at(2).b == "quux");
+        BOOST_TEST(bars.at(3).b == "foobar");
+    }
+    {
+        const toml::value v{
+                toml::table{{"a", 42}, {"b", "baz"}},
+                toml::table{{"a", 43}, {"b", "qux"}},
+                toml::table{{"a", 44}, {"b", "quux"}},
+                toml::table{{"a", 45}, {"b", "foobar"}},
+            };
+
+        const auto foos = toml::get<std::vector<extlib2::foo>>(v);
+        BOOST_TEST(foos.size()  == 4ul);
+        BOOST_TEST(foos.at(0).a == 42);
+        BOOST_TEST(foos.at(1).a == 43);
+        BOOST_TEST(foos.at(2).a == 44);
+        BOOST_TEST(foos.at(3).a == 45);
+
+        BOOST_TEST(foos.at(0).b == "baz");
+        BOOST_TEST(foos.at(1).b == "qux");
+        BOOST_TEST(foos.at(2).b == "quux");
+        BOOST_TEST(foos.at(3).b == "foobar");
+
+        const auto bars = toml::get<std::vector<extlib2::bar>>(v);
+        BOOST_TEST(bars.size()  == 4ul);
+        BOOST_TEST(bars.at(0).a == 42);
+        BOOST_TEST(bars.at(1).a == 43);
+        BOOST_TEST(bars.at(2).a == 44);
+        BOOST_TEST(bars.at(3).a == 45);
+
+        BOOST_TEST(bars.at(0).b == "baz");
+        BOOST_TEST(bars.at(1).b == "qux");
+        BOOST_TEST(bars.at(2).b == "quux");
+        BOOST_TEST(bars.at(3).b == "foobar");
+    }
+
+    {
+        const toml::basic_value<toml::discard_comments, std::map, std::deque>
+            v{
+                toml::table{{"a", 42}, {"b", "baz"}},
+                toml::table{{"a", 43}, {"b", "qux"}},
+                toml::table{{"a", 44}, {"b", "quux"}},
+                toml::table{{"a", 45}, {"b", "foobar"}}
+            };
+
+        const auto foos = toml::get<std::vector<extlib2::foo>>(v);
+        BOOST_TEST(foos.size()  == 4ul);
+        BOOST_TEST(foos.at(0).a == 42);
+        BOOST_TEST(foos.at(1).a == 43);
+        BOOST_TEST(foos.at(2).a == 44);
+        BOOST_TEST(foos.at(3).a == 45);
+
+        BOOST_TEST(foos.at(0).b == "baz");
+        BOOST_TEST(foos.at(1).b == "qux");
+        BOOST_TEST(foos.at(2).b == "quux");
+        BOOST_TEST(foos.at(3).b == "foobar");
+
+        const auto bars = toml::get<std::vector<extlib2::bar>>(v);
+        BOOST_TEST(bars.size()  == 4ul);
+        BOOST_TEST(bars.at(0).a == 42);
+        BOOST_TEST(bars.at(1).a == 43);
+        BOOST_TEST(bars.at(2).a == 44);
+        BOOST_TEST(bars.at(3).a == 45);
+
+        BOOST_TEST(bars.at(0).b == "baz");
+        BOOST_TEST(bars.at(1).b == "qux");
+        BOOST_TEST(bars.at(2).b == "quux");
+        BOOST_TEST(bars.at(3).b == "foobar");
+    }
+
+    // via constructor
+    {
+        const toml::value v{
+                toml::table{{"a", 42}, {"b", "baz"}},
+                toml::table{{"a", 43}, {"b", "qux"}},
+                toml::table{{"a", 44}, {"b", "quux"}},
+                toml::table{{"a", 45}, {"b", "foobar"}}
+            };
+
+        {
+            const auto foobars = toml::get<std::vector<extlib::foobar>>(v);
+            BOOST_TEST(foobars.size()  == 4ul);
+            BOOST_TEST(foobars.at(0).a == 42);
+            BOOST_TEST(foobars.at(1).a == 43);
+            BOOST_TEST(foobars.at(2).a == 44);
+            BOOST_TEST(foobars.at(3).a == 45);
+
+            BOOST_TEST(foobars.at(0).b == "baz");
+            BOOST_TEST(foobars.at(1).b == "qux");
+            BOOST_TEST(foobars.at(2).b == "quux");
+            BOOST_TEST(foobars.at(3).b == "foobar");
+        }
+        {
+            const auto foobars = toml::get<std::vector<extlib2::foobar>>(v);
+            BOOST_TEST(foobars.size()  == 4ul);
+            BOOST_TEST(foobars.at(0).a == 42);
+            BOOST_TEST(foobars.at(1).a == 43);
+            BOOST_TEST(foobars.at(2).a == 44);
+            BOOST_TEST(foobars.at(3).a == 45);
+
+            BOOST_TEST(foobars.at(0).b == "baz");
+            BOOST_TEST(foobars.at(1).b == "qux");
+            BOOST_TEST(foobars.at(2).b == "quux");
+            BOOST_TEST(foobars.at(3).b == "foobar");
+        }
+    }
+    {
+        const toml::basic_value<toml::discard_comments, std::map, std::deque>
+            v{
+                toml::table{{"a", 42}, {"b", "baz"}},
+                toml::table{{"a", 43}, {"b", "qux"}},
+                toml::table{{"a", 44}, {"b", "quux"}},
+                toml::table{{"a", 45}, {"b", "foobar"}}
+            };
+
+        const auto foobars = toml::get<std::vector<extlib2::foobar>>(v);
+        BOOST_TEST(foobars.size()  == 4ul);
+        BOOST_TEST(foobars.at(0).a == 42);
+        BOOST_TEST(foobars.at(1).a == 43);
+        BOOST_TEST(foobars.at(2).a == 44);
+        BOOST_TEST(foobars.at(3).a == 45);
+
+        BOOST_TEST(foobars.at(0).b == "baz");
+        BOOST_TEST(foobars.at(1).b == "qux");
+        BOOST_TEST(foobars.at(2).b == "quux");
+        BOOST_TEST(foobars.at(3).b == "foobar");
+    }
+
+    // via constructor
+    {
+        const toml::value v{
+                {"0", toml::table{{"a", 42}, {"b", "baz"}}},
+                {"1", toml::table{{"a", 43}, {"b", "qux"}}},
+                {"2", toml::table{{"a", 44}, {"b", "quux"}}},
+                {"3", toml::table{{"a", 45}, {"b", "foobar"}}}
+            };
+
+        {
+            const auto foobars = toml::get<std::map<std::string, extlib::foobar>>(v);
+            BOOST_TEST(foobars.size()  == 4ul);
+            BOOST_TEST(foobars.at("0").a == 42);
+            BOOST_TEST(foobars.at("1").a == 43);
+            BOOST_TEST(foobars.at("2").a == 44);
+            BOOST_TEST(foobars.at("3").a == 45);
+
+            BOOST_TEST(foobars.at("0").b == "baz");
+            BOOST_TEST(foobars.at("1").b == "qux");
+            BOOST_TEST(foobars.at("2").b == "quux");
+            BOOST_TEST(foobars.at("3").b == "foobar");
+        }
+        {
+            const auto foobars = toml::get<std::map<std::string, extlib2::foobar>>(v);
+            BOOST_TEST(foobars.size()  == 4ul);
+            BOOST_TEST(foobars.at("0").a == 42);
+            BOOST_TEST(foobars.at("1").a == 43);
+            BOOST_TEST(foobars.at("2").a == 44);
+            BOOST_TEST(foobars.at("3").a == 45);
+
+            BOOST_TEST(foobars.at("0").b == "baz");
+            BOOST_TEST(foobars.at("1").b == "qux");
+            BOOST_TEST(foobars.at("2").b == "quux");
+            BOOST_TEST(foobars.at("3").b == "foobar");
+        }
+    }
+    {
+        const toml::basic_value<toml::discard_comments, std::map, std::deque>
+            v{
+                {"0", toml::table{{"a", 42}, {"b", "baz"}}},
+                {"1", toml::table{{"a", 43}, {"b", "qux"}}},
+                {"2", toml::table{{"a", 44}, {"b", "quux"}}},
+                {"3", toml::table{{"a", 45}, {"b", "foobar"}}}
+            };
+
+        const auto foobars = toml::get<std::map<std::string, extlib::foobar>>(v);
+        BOOST_TEST(foobars.size()  == 4ul);
+        BOOST_TEST(foobars.at("0").a == 42);
+        BOOST_TEST(foobars.at("1").a == 43);
+        BOOST_TEST(foobars.at("2").a == 44);
+        BOOST_TEST(foobars.at("3").a == 45);
+
+        BOOST_TEST(foobars.at("0").b == "baz");
+        BOOST_TEST(foobars.at("1").b == "qux");
+        BOOST_TEST(foobars.at("2").b == "quux");
+        BOOST_TEST(foobars.at("3").b == "foobar");
+    }
+
+}
+
+// ===========================================================================
+
+#ifndef TOML11_WITHOUT_DEFINE_NON_INTRUSIVE
+
+namespace extlib3
+{
+struct foo
+{
+    int a;
+    std::string b;
+};
+struct bar
+{
+    int         a;
+    std::string b;
+    foo         f;
+};
+
+} // extlib3
+
+TOML11_DEFINE_CONVERSION_NON_INTRUSIVE(extlib3::foo, a, b)
+TOML11_DEFINE_CONVERSION_NON_INTRUSIVE(extlib3::bar, a, b, f)
+
+BOOST_AUTO_TEST_CASE(test_conversion_via_macro)
+{
+    {
+        const toml::value v{{"a", 42}, {"b", "baz"}};
+
+        const auto foo = toml::get<extlib3::foo>(v);
+        BOOST_TEST(foo.a == 42);
+        BOOST_TEST(foo.b == "baz");
+
+        const toml::value v2(foo);
+        BOOST_TEST(v2 == v);
+    }
+    {
+        const toml::basic_value<toml::discard_comments, std::map, std::deque> v{
+            {"a", 42}, {"b", "baz"}
+        };
+
+        const auto foo = toml::get<extlib3::foo>(v);
+        BOOST_TEST(foo.a == 42);
+        BOOST_TEST(foo.b == "baz");
+
+        const toml::basic_value<toml::discard_comments, std::map, std::deque> v2(foo);
+        BOOST_TEST(v2 == v);
+    }
+
+    // -----------------------------------------------------------------------
+
+    {
+        const toml::value v{
+            {"a", 42},
+            {"b", "bar.b"},
+            {"f", toml::table{{"a", 42}, {"b", "foo.b"}}}
+        };
+
+        const auto bar = toml::get<extlib3::bar>(v);
+        BOOST_TEST(bar.a == 42);
+        BOOST_TEST(bar.b == "bar.b");
+        BOOST_TEST(bar.f.a == 42);
+        BOOST_TEST(bar.f.b == "foo.b");
+
+        const toml::value v2(bar);
+        BOOST_TEST(v2 == v);
+    }
+    {
+        const toml::basic_value<toml::discard_comments, std::map, std::deque> v{
+            {"a", 42},
+            {"b", "bar.b"},
+            {"f", toml::table{{"a", 42}, {"b", "foo.b"}}}
+        };
+
+        const auto bar = toml::get<extlib3::bar>(v);
+        BOOST_TEST(bar.a == 42);
+        BOOST_TEST(bar.b == "bar.b");
+        BOOST_TEST(bar.f.a == 42);
+        BOOST_TEST(bar.f.b == "foo.b");
+
+        const toml::basic_value<toml::discard_comments, std::map, std::deque> v2(bar);
+        BOOST_TEST(v2 == v);
+    }
+}
+#endif // TOML11_WITHOUT_DEFINE_NON_INTRUSIVE

tests/test_find.cpp

@@ -0,0 +1,827 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+#include <array>
+#include <deque>
+#include <list>
+#include <map>
+#include <tuple>
+#include <unordered_map>
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+#include <string_view>
+#endif
+
+using test_value_types = std::tuple<
+    toml::basic_value<toml::discard_comments>,
+    toml::basic_value<toml::preserve_comments>,
+    toml::basic_value<toml::discard_comments,  std::map, std::deque>,
+    toml::basic_value<toml::preserve_comments, std::map, std::deque>
+    >;
+
+BOOST_AUTO_TEST_CASE(test_find_throws)
+{
+    // -----------------------------------------------------------------------
+    // const-reference version
+    {
+        // value is not a table
+        const toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, "key"), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        const toml::value v{{"key", 42}};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, "key"), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        const toml::value v{{"key", 42}};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(v, "different_key"),
+                          std::out_of_range);
+    }
+    {
+        // the positive control.
+        const toml::value v{{"key", 42}};
+        BOOST_TEST(42 == toml::find<int>(v, "key"));
+    }
+
+    // -----------------------------------------------------------------------
+    // reference version
+    {
+        // value is not a table
+        toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, "key"), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        toml::value v{{"key", 42}};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, "key"), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        toml::value v{{"key", 42}};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(v, "different_key"),
+                          std::out_of_range);
+    }
+    {
+        // the positive control.
+        toml::value v{{"key", 42}};
+        BOOST_TEST(42 == toml::find<int>(v, "key"));
+    }
+
+    // -----------------------------------------------------------------------
+    // move version
+
+    {
+        // value is not a table
+        toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(std::move(v), "key"), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        toml::value v{{"key", 42}};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(std::move(v), "key"), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        toml::value v{{"key", 42}};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(std::move(v), "different_key"),
+                          std::out_of_range);
+    }
+    {
+        // the positive control.
+        toml::value v{{"key", 42}};
+        BOOST_TEST(42 == toml::find<int>(std::move(v), "key"));
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_find_array_throws)
+{
+    // -----------------------------------------------------------------------
+    // const-reference version
+    {
+        // value is not an array
+        const toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        const toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        const toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(v, 6), std::out_of_range);
+    }
+    {
+        // the positive control.
+        const toml::value v{1, 2, 3, 4, 5};
+        BOOST_TEST(3 == toml::find<int>(v, 2));
+    }
+
+    // -----------------------------------------------------------------------
+    // non-const reference version
+    {
+        // value is not an array
+        toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(v, 6), std::out_of_range);
+    }
+    {
+        // the positive control.
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_TEST(3 == toml::find<int>(v, 2));
+    }
+
+    // -----------------------------------------------------------------------
+    // move version
+    {
+        // value is not an array
+        toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(std::move(v), 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(std::move(v), 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(std::move(v), 6), std::out_of_range);
+    }
+    {
+        // the positive control.
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_TEST(3 == toml::find<int>(std::move(v), 2));
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_find_recursive)
+{
+    // recursively search tables
+    {
+        toml::value v{
+            {"a", {
+                {"b", {
+                    {"c", {
+                        {"d", 42}
+                    }}
+                }}
+            }}
+        };
+        BOOST_TEST(42 == toml::find<int>(v, "a", "b", "c", "d"));
+
+        // reference that can be used to modify the content
+        auto& num = toml::find<toml::integer>(v, "a", "b", "c", "d");
+        num = 54;
+        BOOST_TEST(54 == toml::find<int>(v, "a", "b", "c", "d"));
+
+        const std::string a("a"), b("b"), c("c"), d("d");
+        auto& num2 = toml::find<toml::integer>(v, a, b, c, d);
+        num2 = 42;
+        BOOST_TEST(42 == toml::find<int>(v, a, b, c, d));
+
+        auto num3 = toml::find<toml::integer>(v, a, "b", c, "d");
+        BOOST_TEST(42 == num3);
+
+        auto num4 = toml::find<toml::integer>(std::move(v), a, b, c, d);
+        BOOST_TEST(42 == num4);
+    }
+    // recursively search arrays
+    {
+        toml::value v{
+            toml::array{"array", "of", "string"},
+            toml::array{toml::array{1, 2, 3}, toml::array{3.14, 2.71}}
+        };
+        BOOST_TEST("array"  == toml::find<std::string>(v, 0, 0));
+        BOOST_TEST("of"     == toml::find<std::string>(v, 0, 1));
+        BOOST_TEST("string" == toml::find<std::string>(v, 0, 2));
+
+        BOOST_TEST(1 == toml::find<int>(v, 1, 0, 0));
+        BOOST_TEST(2 == toml::find<int>(v, 1, 0, 1));
+        BOOST_TEST(3 == toml::find<int>(v, 1, 0, 2));
+
+        BOOST_TEST(3.14 == toml::find<double>(v, 1, 1, 0));
+        BOOST_TEST(2.71 == toml::find<double>(v, 1, 1, 1));
+
+        // reference that can be used to modify the content
+        auto& num = toml::find<toml::integer>(v, 1, 0, 2);
+        num = 42;
+        BOOST_TEST( 1 == toml::find<int>(v, 1, 0, 0));
+        BOOST_TEST( 2 == toml::find<int>(v, 1, 0, 1));
+        BOOST_TEST(42 == toml::find<int>(v, 1, 0, 2));
+
+        // move value
+        auto num2 = toml::find<toml::integer>(std::move(v), 1, 0, 2);
+        BOOST_TEST(42 == num2);
+    }
+    // recursively search mixtures
+    {
+        toml::value v = toml::table{{"array", toml::array{
+                toml::array{1,   2,   3},
+                toml::array{
+                    toml::table{{"foo", "bar"}, {"baz", "qux"}},
+                    toml::table{{"pi",   3.14}, {"e",    2.71}}
+                }}
+            }};
+
+        BOOST_TEST(1 == toml::find<int>(v, "array", 0, 0));
+        BOOST_TEST(2 == toml::find<int>(v, "array", 0, 1));
+        BOOST_TEST(3 == toml::find<int>(v, "array", 0, 2));
+
+        BOOST_TEST("bar" == toml::find<std::string>(v, "array", 1, 0, "foo"));
+        BOOST_TEST("qux" == toml::find<std::string>(v, "array", 1, 0, "baz"));
+
+        BOOST_TEST(3.14 == toml::find<double>(v, "array", 1, 1, "pi"));
+        BOOST_TEST(2.71 == toml::find<double>(v, "array", 1, 1, "e"));
+
+        const std::string ar("array");
+        const auto ar_c = "array";
+
+        const std::string pi("pi");
+        const auto pi_c = "pi";
+
+        BOOST_TEST(3.14 == toml::find<double>(v, ar, 1, 1, "pi"));
+        BOOST_TEST(3.14 == toml::find<double>(v, ar, 1, 1, pi));
+        BOOST_TEST(3.14 == toml::find<double>(v, ar, 1, 1, pi_c));
+
+        BOOST_TEST(3.14 == toml::find<double>(v, ar_c, 1, 1, "pi"));
+        BOOST_TEST(3.14 == toml::find<double>(v, ar_c, 1, 1, pi));
+        BOOST_TEST(3.14 == toml::find<double>(v, ar_c, 1, 1, pi_c));
+
+        BOOST_TEST(3.14 == toml::find<double>(v, "array", 1, 1, pi));
+        BOOST_TEST(3.14 == toml::find<double>(v, "array", 1, 1, pi_c));
+    }
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
+{
+    {
+        value_type v{{"key", true}};
+        BOOST_TEST(true == toml::find<toml::boolean>(v, "key"));
+
+        toml::find<toml::boolean>(v, "key") = false;
+        BOOST_TEST(false == toml::find<toml::boolean>(v, "key"));
+
+        const auto moved = toml::find<toml::boolean>(std::move(v), "key");
+        BOOST_TEST(false == moved);
+    }
+    {
+        value_type v{{"key", 42}};
+        BOOST_TEST(toml::integer(42) == toml::find<toml::integer>(v, "key"));
+
+        toml::find<toml::integer>(v, "key") = 54;
+        BOOST_TEST(toml::integer(54) == toml::find<toml::integer>(v, "key"));
+
+        const auto moved = toml::find<toml::integer>(std::move(v), "key");
+        BOOST_TEST(toml::integer(54) == moved);
+    }
+    {
+        value_type v{{"key", 3.14}};
+        BOOST_TEST(toml::floating(3.14) == toml::find<toml::floating>(v, "key"));
+
+        toml::find<toml::floating>(v, "key") = 2.71;
+        BOOST_TEST(toml::floating(2.71) == toml::find<toml::floating>(v, "key"));
+
+        const auto moved = toml::find<toml::floating>(std::move(v), "key");
+        BOOST_TEST(toml::floating(2.71) == moved);
+    }
+    {
+        value_type v{{"key", "foo"}};
+        BOOST_TEST(toml::string("foo", toml::string_t::basic) ==
+                          toml::find<toml::string>(v, "key"));
+
+        toml::find<toml::string>(v, "key").str += "bar";
+        BOOST_TEST(toml::string("foobar", toml::string_t::basic) ==
+                          toml::find<toml::string>(v, "key"));
+
+        const auto moved = toml::find<toml::string>(std::move(v), "key");
+        BOOST_TEST(toml::string("foobar", toml::string_t::basic) == moved);
+    }
+    {
+        value_type v{{"key", value_type("foo", toml::string_t::literal)}};
+        BOOST_TEST(toml::string("foo", toml::string_t::literal) ==
+                          toml::find<toml::string>(v, "key"));
+
+        toml::find<toml::string>(v, "key").str += "bar";
+        BOOST_TEST(toml::string("foobar", toml::string_t::literal) ==
+                          toml::find<toml::string>(v, "key"));
+
+        const auto moved = toml::find<toml::string>(std::move(v), "key");
+        BOOST_TEST(toml::string("foobar", toml::string_t::literal) == moved);
+    }
+    {
+        toml::local_date d(2018, toml::month_t::Apr, 22);
+        value_type v{{"key", d}};
+        BOOST_CHECK(d == toml::find<toml::local_date>(v, "key"));
+
+        toml::find<toml::local_date>(v, "key").year = 2017;
+        d.year = 2017;
+        BOOST_CHECK(d == toml::find<toml::local_date>(v, "key"));
+
+        const auto moved = toml::find<toml::local_date>(std::move(v), "key");
+        BOOST_CHECK(d == moved);
+    }
+    {
+        toml::local_time t(12, 30, 45);
+        value_type v{{"key", t}};
+        BOOST_CHECK(t == toml::find<toml::local_time>(v, "key"));
+
+        toml::find<toml::local_time>(v, "key").hour = 9;
+        t.hour = 9;
+        BOOST_CHECK(t == toml::find<toml::local_time>(v, "key"));
+
+        const auto moved = toml::find<toml::local_time>(std::move(v), "key");
+        BOOST_CHECK(t == moved);
+    }
+    {
+        toml::local_datetime dt(toml::local_date(2018, toml::month_t::Apr, 22),
+                                toml::local_time(12, 30, 45));
+        value_type v{{"key", dt}};
+        BOOST_CHECK(dt == toml::find<toml::local_datetime>(v, "key"));
+
+        toml::find<toml::local_datetime>(v, "key").date.year = 2017;
+        dt.date.year = 2017;
+        BOOST_CHECK(dt == toml::find<toml::local_datetime>(v, "key"));
+
+        const auto moved = toml::find<toml::local_datetime>(std::move(v), "key");
+        BOOST_CHECK(dt == moved);
+    }
+    {
+        toml::offset_datetime dt(toml::local_datetime(
+                    toml::local_date(2018, toml::month_t::Apr, 22),
+                    toml::local_time(12, 30, 45)), toml::time_offset(9, 0));
+        value_type v{{"key", dt}};
+        BOOST_CHECK(dt == toml::find<toml::offset_datetime>(v, "key"));
+
+        toml::find<toml::offset_datetime>(v, "key").date.year = 2017;
+        dt.date.year = 2017;
+        BOOST_CHECK(dt == toml::find<toml::offset_datetime>(v, "key"));
+
+        const auto moved = toml::find<toml::offset_datetime>(std::move(v), "key");
+        BOOST_CHECK(dt == moved);
+    }
+    {
+        typename value_type::array_type vec;
+        vec.push_back(value_type(42));
+        vec.push_back(value_type(54));
+        value_type v{{"key", vec}};
+
+        const bool result1 = (vec == toml::find<typename value_type::array_type>(v, "key"));
+        BOOST_CHECK(result1);
+
+        toml::find<typename value_type::array_type>(v, "key").push_back(value_type(123));
+        vec.push_back(value_type(123));
+
+        const bool result2 = (vec == toml::find<typename value_type::array_type>(v, "key"));
+        BOOST_CHECK(result2);
+
+        const auto moved = toml::find<typename value_type::array_type>(std::move(v), "key");
+        const bool result3 = (vec == moved);
+        BOOST_CHECK(result3);
+    }
+    {
+        typename value_type::table_type tab;
+        tab["key1"] = value_type(42);
+        tab["key2"] = value_type(3.14);
+        value_type v{{"key", tab}};
+        const bool result1 = (tab == toml::find<typename value_type::table_type>(v, "key"));
+        BOOST_CHECK(result1);
+
+        toml::find<typename value_type::table_type>(v, "key")["key3"] = value_type(123);
+        tab["key3"] = value_type(123);
+        const bool result2 = (tab == toml::find<typename value_type::table_type>(v, "key"));
+        BOOST_CHECK(result2);
+
+        const auto moved = toml::find<typename value_type::table_type>(std::move(v), "key");
+        const bool result3 = (tab == moved);
+        BOOST_CHECK(result3);
+    }
+    {
+        value_type v1(42);
+        value_type v{{"key", v1}};
+        BOOST_CHECK(v1 == toml::find(v, "key"));
+
+        value_type v2(54);
+        toml::find(v, "key") = v2;
+        BOOST_CHECK(v2 == toml::find(v, "key"));
+
+        const auto moved = toml::find(std::move(v), "key");
+        BOOST_CHECK(v2 == moved);
+    }
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_integer_type, value_type, test_value_types)
+{
+    {
+        value_type v{{"key", 42}};
+        BOOST_TEST(int(42)           == toml::find<int          >(v, "key"));
+        BOOST_TEST(short(42)         == toml::find<short        >(v, "key"));
+        BOOST_TEST(char(42)          == toml::find<char         >(v, "key"));
+        BOOST_TEST(unsigned(42)      == toml::find<unsigned     >(v, "key"));
+        BOOST_TEST(long(42)          == toml::find<long         >(v, "key"));
+        BOOST_TEST(std::int64_t(42)  == toml::find<std::int64_t >(v, "key"));
+        BOOST_TEST(std::uint64_t(42) == toml::find<std::uint64_t>(v, "key"));
+        BOOST_TEST(std::int16_t(42)  == toml::find<std::int16_t >(v, "key"));
+        BOOST_TEST(std::uint16_t(42) == toml::find<std::uint16_t>(v, "key"));
+        BOOST_TEST(std::uint16_t(42) == toml::find<std::uint16_t>(std::move(v), "key"));
+    }
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_floating_type, value_type, test_value_types)
+{
+    {
+        value_type v{{"key", 3.14}};
+        const double ref(3.14);
+        BOOST_TEST(static_cast<float      >(ref) == toml::find<float      >(v, "key"));
+        BOOST_TEST(                         ref  == toml::find<double     >(v, "key"));
+        BOOST_TEST(static_cast<long double>(ref) == toml::find<long double>(v, "key"));
+        BOOST_TEST(static_cast<float      >(ref) == toml::find<float      >(std::move(v), "key"));
+    }
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_string_type, value_type, test_value_types)
+{
+    {
+        value_type v{{"key", toml::string("foo", toml::string_t::basic)}};
+        BOOST_TEST("foo" == toml::find<std::string>(v, "key"));
+        toml::find<std::string>(v, "key") += "bar";
+        BOOST_TEST("foobar" == toml::find<std::string>(v, "key"));
+    }
+    {
+        value_type v{{"key", toml::string("foo", toml::string_t::literal)}};
+        BOOST_TEST("foo" == toml::find<std::string>(v, "key"));
+        toml::find<std::string>(v, "key") += "bar";
+        BOOST_TEST("foobar" == toml::find<std::string>(v, "key"));
+    }
+    {
+        value_type v{{"key", toml::string("foo", toml::string_t::literal)}};
+        const auto moved = toml::find<std::string>(std::move(v), "key");
+        BOOST_TEST("foo" == moved);
+    }
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+    {
+        value_type v{{"key", toml::string("foo", toml::string_t::basic)}};
+        BOOST_TEST("foo" == toml::find<std::string_view>(v, "key"));
+    }
+    {
+        value_type v{{"key", toml::string("foo", toml::string_t::literal)}};
+        BOOST_TEST("foo" == toml::find<std::string_view>(v, "key"));
+    }
+#endif
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_array, value_type, test_value_types)
+{
+    value_type v{{"key", {42, 54, 69, 72}}};
+
+    const std::vector<int>         vec = toml::find<std::vector<int>>(v, "key");
+    const std::list<short>         lst = toml::find<std::list<short>>(v, "key");
+    const std::deque<std::int64_t> deq = toml::find<std::deque<std::int64_t>>(v, "key");
+
+    BOOST_TEST(42 == vec.at(0));
+    BOOST_TEST(54 == vec.at(1));
+    BOOST_TEST(69 == vec.at(2));
+    BOOST_TEST(72 == vec.at(3));
+
+    std::list<short>::const_iterator iter = lst.begin();
+    BOOST_TEST(static_cast<short>(42) == *(iter++));
+    BOOST_TEST(static_cast<short>(54) == *(iter++));
+    BOOST_TEST(static_cast<short>(69) == *(iter++));
+    BOOST_TEST(static_cast<short>(72) == *(iter++));
+
+    BOOST_TEST(static_cast<std::int64_t>(42) == deq.at(0));
+    BOOST_TEST(static_cast<std::int64_t>(54) == deq.at(1));
+    BOOST_TEST(static_cast<std::int64_t>(69) == deq.at(2));
+    BOOST_TEST(static_cast<std::int64_t>(72) == deq.at(3));
+
+    std::array<int, 4> ary = toml::find<std::array<int, 4>>(v, "key");
+    BOOST_TEST(42 == ary.at(0));
+    BOOST_TEST(54 == ary.at(1));
+    BOOST_TEST(69 == ary.at(2));
+    BOOST_TEST(72 == ary.at(3));
+
+    std::tuple<int, short, unsigned, long> tpl =
+        toml::find<std::tuple<int, short, unsigned, long>>(v, "key");
+    BOOST_TEST(                      42  == std::get<0>(tpl));
+    BOOST_TEST(static_cast<short   >(54) == std::get<1>(tpl));
+    BOOST_TEST(static_cast<unsigned>(69) == std::get<2>(tpl));
+    BOOST_TEST(static_cast<long    >(72) == std::get<3>(tpl));
+
+    value_type p{{"key", {3.14, 2.71}}};
+    std::pair<double, double> pr = toml::find<std::pair<double, double> >(p, "key");
+    BOOST_TEST(3.14 == pr.first);
+    BOOST_TEST(2.71 == pr.second);
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_move_toml_array, value_type, test_value_types)
+{
+    value_type v1{{"key", {42, 54, 69, 72}}};
+    value_type v2{{"key", {42, 54, 69, 72}}};
+    value_type v3{{"key", {42, 54, 69, 72}}};
+    value_type v4{{"key", {42, 54, 69, 72}}};
+    value_type v5{{"key", {42, 54, 69, 72}}};
+
+    const std::vector<int>         vec = toml::find<std::vector<int>>(std::move(v1), "key");
+    const std::list<short>         lst = toml::find<std::list<short>>(std::move(v2), "key");
+    const std::deque<std::int64_t> deq = toml::find<std::deque<std::int64_t>>(std::move(v3), "key");
+
+    BOOST_TEST(42 == vec.at(0));
+    BOOST_TEST(54 == vec.at(1));
+    BOOST_TEST(69 == vec.at(2));
+    BOOST_TEST(72 == vec.at(3));
+
+    std::list<short>::const_iterator iter = lst.begin();
+    BOOST_TEST(static_cast<short>(42) == *(iter++));
+    BOOST_TEST(static_cast<short>(54) == *(iter++));
+    BOOST_TEST(static_cast<short>(69) == *(iter++));
+    BOOST_TEST(static_cast<short>(72) == *(iter++));
+
+    BOOST_TEST(static_cast<std::int64_t>(42) == deq.at(0));
+    BOOST_TEST(static_cast<std::int64_t>(54) == deq.at(1));
+    BOOST_TEST(static_cast<std::int64_t>(69) == deq.at(2));
+    BOOST_TEST(static_cast<std::int64_t>(72) == deq.at(3));
+
+    std::array<int, 4> ary = toml::find<std::array<int, 4>>(std::move(v4), "key");
+    BOOST_TEST(42 == ary.at(0));
+    BOOST_TEST(54 == ary.at(1));
+    BOOST_TEST(69 == ary.at(2));
+    BOOST_TEST(72 == ary.at(3));
+
+    std::tuple<int, short, unsigned, long> tpl =
+        toml::find<std::tuple<int, short, unsigned, long>>(std::move(v5), "key");
+    BOOST_TEST(                      42  == std::get<0>(tpl));
+    BOOST_TEST(static_cast<short   >(54) == std::get<1>(tpl));
+    BOOST_TEST(static_cast<unsigned>(69) == std::get<2>(tpl));
+    BOOST_TEST(static_cast<long    >(72) == std::get<3>(tpl));
+
+    value_type p{{"key", {3.14, 2.71}}};
+    std::pair<double, double> pr = toml::find<std::pair<double, double> >(std::move(p), "key");
+    BOOST_TEST(3.14 == pr.first);
+    BOOST_TEST(2.71 == pr.second);
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_array_of_array, value_type, test_value_types)
+{
+    value_type v1{42, 54, 69, 72};
+    value_type v2{"foo", "bar", "baz"};
+    value_type v{{"key", {v1, v2}}};
+
+    std::pair<std::vector<int>, std::vector<std::string>> p =
+        toml::find<std::pair<std::vector<int>, std::vector<std::string>>>(v, "key");
+
+    BOOST_TEST(p.first.at(0) == 42);
+    BOOST_TEST(p.first.at(1) == 54);
+    BOOST_TEST(p.first.at(2) == 69);
+    BOOST_TEST(p.first.at(3) == 72);
+
+    BOOST_TEST(p.second.at(0) == "foo");
+    BOOST_TEST(p.second.at(1) == "bar");
+    BOOST_TEST(p.second.at(2) == "baz");
+
+    std::tuple<std::vector<int>, std::vector<std::string>> t =
+        toml::find<std::tuple<std::vector<int>, std::vector<std::string>>>(v, "key");
+
+    BOOST_TEST(std::get<0>(t).at(0) == 42);
+    BOOST_TEST(std::get<0>(t).at(1) == 54);
+    BOOST_TEST(std::get<0>(t).at(2) == 69);
+    BOOST_TEST(std::get<0>(t).at(3) == 72);
+
+    BOOST_TEST(std::get<1>(t).at(0) == "foo");
+    BOOST_TEST(std::get<1>(t).at(1) == "bar");
+    BOOST_TEST(std::get<1>(t).at(2) == "baz");
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_move_toml_array_of_array, value_type, test_value_types)
+{
+    value_type a1{42, 54, 69, 72};
+    value_type a2{"foo", "bar", "baz"};
+    value_type v1{{"key", {a1, a2}}};
+    value_type v2{{"key", {a1, a2}}};
+
+    std::pair<std::vector<int>, std::vector<std::string>> p =
+        toml::find<std::pair<std::vector<int>, std::vector<std::string>>>(std::move(v1), "key");
+
+    BOOST_TEST(p.first.at(0) == 42);
+    BOOST_TEST(p.first.at(1) == 54);
+    BOOST_TEST(p.first.at(2) == 69);
+    BOOST_TEST(p.first.at(3) == 72);
+
+    BOOST_TEST(p.second.at(0) == "foo");
+    BOOST_TEST(p.second.at(1) == "bar");
+    BOOST_TEST(p.second.at(2) == "baz");
+
+    std::tuple<std::vector<int>, std::vector<std::string>> t =
+        toml::find<std::tuple<std::vector<int>, std::vector<std::string>>>(std::move(v2), "key");
+
+    BOOST_TEST(std::get<0>(t).at(0) == 42);
+    BOOST_TEST(std::get<0>(t).at(1) == 54);
+    BOOST_TEST(std::get<0>(t).at(2) == 69);
+    BOOST_TEST(std::get<0>(t).at(3) == 72);
+
+    BOOST_TEST(std::get<1>(t).at(0) == "foo");
+    BOOST_TEST(std::get<1>(t).at(1) == "bar");
+    BOOST_TEST(std::get<1>(t).at(2) == "baz");
+}
+
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_table, value_type, test_value_types)
+{
+    {
+        value_type v1{{"key", {
+                {"key1", 1}, {"key2", 2}, {"key3", 3}, {"key4", 4}
+            }}};
+        const auto v = toml::find<std::map<std::string, int>>(v1, "key");
+        BOOST_TEST(v.at("key1") == 1);
+        BOOST_TEST(v.at("key2") == 2);
+        BOOST_TEST(v.at("key3") == 3);
+        BOOST_TEST(v.at("key4") == 4);
+    }
+    {
+        value_type v1{{"key", {
+                {"key1", 1}, {"key2", 2}, {"key3", 3}, {"key4", 4}
+            }}};
+        const auto v = toml::find<std::map<std::string, int>>(std::move(v1), "key");
+        BOOST_TEST(v.at("key1") == 1);
+        BOOST_TEST(v.at("key2") == 2);
+        BOOST_TEST(v.at("key3") == 3);
+        BOOST_TEST(v.at("key4") == 4);
+    }
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_local_date, value_type, test_value_types)
+{
+    {
+        value_type v1{{"key", toml::local_date{2018, toml::month_t::Apr, 1}}};
+        const auto date = std::chrono::system_clock::to_time_t(
+                toml::find<std::chrono::system_clock::time_point>(v1, "key"));
+
+        std::tm t;
+        t.tm_year = 2018 - 1900;
+        t.tm_mon  = 4    - 1;
+        t.tm_mday = 1;
+        t.tm_hour = 0;
+        t.tm_min  = 0;
+        t.tm_sec  = 0;
+        t.tm_isdst = -1;
+        const auto c = std::mktime(&t);
+        BOOST_TEST(c == date);
+    }
+    {
+        value_type v1{{"key", toml::local_date{2018, toml::month_t::Apr, 1}}};
+        const auto date = std::chrono::system_clock::to_time_t(
+                toml::find<std::chrono::system_clock::time_point>(std::move(v1), "key"));
+
+        std::tm t;
+        t.tm_year = 2018 - 1900;
+        t.tm_mon  = 4    - 1;
+        t.tm_mday = 1;
+        t.tm_hour = 0;
+        t.tm_min  = 0;
+        t.tm_sec  = 0;
+        t.tm_isdst = -1;
+        const auto c = std::mktime(&t);
+        BOOST_TEST(c == date);
+    }
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_local_time, value_type, test_value_types)
+{
+    {
+        value_type v1{{"key", toml::local_time{12, 30, 45}}};
+        const auto time = toml::find<std::chrono::seconds>(v1, "key");
+        BOOST_CHECK(time == std::chrono::hours(12) +
+                            std::chrono::minutes(30) + std::chrono::seconds(45));
+    }
+    {
+        value_type v1{{"key", toml::local_time{12, 30, 45}}};
+        const auto time = toml::find<std::chrono::seconds>(std::move(v1), "key");
+        BOOST_CHECK(time == std::chrono::hours(12) +
+                            std::chrono::minutes(30) + std::chrono::seconds(45));
+    }
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_local_datetime, value_type, test_value_types)
+{
+    {
+        value_type v1{{"key", toml::local_datetime(
+                    toml::local_date{2018, toml::month_t::Apr, 1},
+                    toml::local_time{12, 30, 45})}};
+
+        const auto date = std::chrono::system_clock::to_time_t(
+                toml::find<std::chrono::system_clock::time_point>(v1, "key"));
+        std::tm t;
+        t.tm_year = 2018 - 1900;
+        t.tm_mon  = 4    - 1;
+        t.tm_mday = 1;
+        t.tm_hour = 12;
+        t.tm_min  = 30;
+        t.tm_sec  = 45;
+        t.tm_isdst = -1;
+        const auto c = std::mktime(&t);
+        BOOST_TEST(c == date);
+    }
+    {
+        value_type v1{{"key", toml::local_datetime(
+                    toml::local_date{2018, toml::month_t::Apr, 1},
+                    toml::local_time{12, 30, 45})}};
+
+        const auto date = std::chrono::system_clock::to_time_t(
+                toml::find<std::chrono::system_clock::time_point>(std::move(v1), "key"));
+        std::tm t;
+        t.tm_year = 2018 - 1900;
+        t.tm_mon  = 4    - 1;
+        t.tm_mday = 1;
+        t.tm_hour = 12;
+        t.tm_min  = 30;
+        t.tm_sec  = 45;
+        t.tm_isdst = -1;
+        const auto c = std::mktime(&t);
+        BOOST_TEST(c == date);
+    }
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_offset_datetime, value_type, test_value_types)
+{
+    {
+        value_type v1{{"key", toml::offset_datetime(
+                    toml::local_date{2018, toml::month_t::Apr, 1},
+                    toml::local_time{12, 30, 0},
+                    toml::time_offset{9, 0})}};
+        //    2018-04-01T12:30:00+09:00
+        // == 2018-04-01T03:30:00Z
+
+        const auto date = toml::find<std::chrono::system_clock::time_point>(v1, "key");
+        const auto timet = std::chrono::system_clock::to_time_t(date);
+
+        // get time_t as gmtime (2018-04-01T03:30:00Z)
+        const auto tmp = std::gmtime(std::addressof(timet)); // XXX not threadsafe!
+        BOOST_CHECK(tmp);
+        const auto tm = *tmp;
+        BOOST_TEST(tm.tm_year + 1900 == 2018);
+        BOOST_TEST(tm.tm_mon  + 1 ==       4);
+        BOOST_TEST(tm.tm_mday ==           1);
+        BOOST_TEST(tm.tm_hour ==           3);
+        BOOST_TEST(tm.tm_min ==           30);
+        BOOST_TEST(tm.tm_sec ==            0);
+    }
+
+    {
+        value_type v1{{"key", toml::offset_datetime(
+                    toml::local_date{2018, toml::month_t::Apr, 1},
+                    toml::local_time{12, 30, 0},
+                    toml::time_offset{-8, 0})}};
+        //    2018-04-01T12:30:00-08:00
+        // == 2018-04-01T20:30:00Z
+
+        const auto date = toml::find<std::chrono::system_clock::time_point>(v1, "key");
+        const auto timet = std::chrono::system_clock::to_time_t(date);
+
+        // get time_t as gmtime (2018-04-01T03:30:00Z)
+        const auto tmp = std::gmtime(std::addressof(timet)); // XXX not threadsafe!
+        BOOST_CHECK(tmp);
+        const auto tm = *tmp;
+        BOOST_TEST(tm.tm_year + 1900 == 2018);
+        BOOST_TEST(tm.tm_mon  + 1 ==       4);
+        BOOST_TEST(tm.tm_mday ==           1);
+        BOOST_TEST(tm.tm_hour ==          20);
+        BOOST_TEST(tm.tm_min ==           30);
+        BOOST_TEST(tm.tm_sec ==            0);
+    }
+
+    {
+        value_type v1{{"key", toml::offset_datetime(
+                    toml::local_date{2018, toml::month_t::Apr, 1},
+                    toml::local_time{12, 30, 0},
+                    toml::time_offset{-8, 0})}};
+        //    2018-04-01T12:30:00-08:00
+        // == 2018-04-01T20:30:00Z
+
+        const auto date = toml::find<std::chrono::system_clock::time_point>(std::move(v1), "key");
+        const auto timet = std::chrono::system_clock::to_time_t(date);
+
+        // get time_t as gmtime (2018-04-01T03:30:00Z)
+        const auto tmp = std::gmtime(std::addressof(timet)); // XXX not threadsafe!
+        BOOST_CHECK(tmp);
+        const auto tm = *tmp;
+        BOOST_TEST(tm.tm_year + 1900 == 2018);
+        BOOST_TEST(tm.tm_mon  + 1 ==       4);
+        BOOST_TEST(tm.tm_mday ==           1);
+        BOOST_TEST(tm.tm_hour ==          20);
+        BOOST_TEST(tm.tm_min ==           30);
+        BOOST_TEST(tm.tm_sec ==            0);
+    }
+}

tests/test_find_or.cpp

@@ -0,0 +1,538 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+#include <array>
+#include <deque>
+#include <list>
+#include <map>
+#include <tuple>
+#include <unordered_map>
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+#include <string_view>
+#endif
+
+using test_value_types = std::tuple<
+    toml::basic_value<toml::discard_comments>,
+    toml::basic_value<toml::preserve_comments>,
+    toml::basic_value<toml::discard_comments,  std::map, std::deque>,
+    toml::basic_value<toml::preserve_comments, std::map, std::deque>
+>;
+
+namespace test
+{
+template<typename charT, typename traits, typename T, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const std::vector<T, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << i << ' ';}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits, typename T, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const std::deque<T, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << i << ' ';}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits, typename T, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const std::list<T, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << i << ' ';}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits,
+         typename Key, typename Value, typename Comp, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os,
+           const std::map<Key, Value, Comp, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << '{' << i.first << ", " << i.second << "} ";}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits,
+         typename Key, typename Value, typename Hash, typename Eq, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os,
+           const std::unordered_map<Key, Value, Hash, Eq, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << '{' << i.first << ", " << i.second << "} ";}
+    os << ']';
+    return os;
+}
+} // test
+
+#define TOML11_TEST_FIND_OR_EXACT(toml_type, init_expr, opt_expr)\
+    {                                                           \
+        using namespace test;                                   \
+        const toml::toml_type init init_expr ;                  \
+        const toml::toml_type opt  opt_expr ;                   \
+        const value_type v{{"key", init}};                      \
+        BOOST_TEST(init != opt);                                \
+        BOOST_TEST(init == toml::find_or(v, "key", opt));       \
+    }                                                           \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_exact, value_type, test_value_types)
+{
+    TOML11_TEST_FIND_OR_EXACT(boolean,         ( true), (false))
+    TOML11_TEST_FIND_OR_EXACT(integer,         (   42), (   54))
+    TOML11_TEST_FIND_OR_EXACT(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_FIND_OR_EXACT(string,          ("foo"), ("bar"))
+    TOML11_TEST_FIND_OR_EXACT(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_FIND_OR_EXACT(local_date,      (2019, toml::month_t::Apr, 1),
+                                              (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_FIND_OR_EXACT(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_FIND_OR_EXACT(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        const typename value_type::array_type init{1,2,3,4,5};
+        const typename value_type::array_type opt {6,7,8,9,10};
+        const value_type v{{"key", init}};
+        BOOST_TEST(init != opt);
+        BOOST_TEST(init == toml::find_or(v, "key", opt));
+    }
+    {
+        const typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        const typename value_type::table_type opt {{"key1", 54}, {"key2", "bar"}};
+        const value_type v{{"key", init}};
+        BOOST_TEST(init != opt);
+        BOOST_TEST(init == toml::find_or(v, "key", opt));
+    }
+}
+#undef TOML11_TEST_FIND_OR_EXACT
+
+#define TOML11_TEST_FIND_OR_MOVE(toml_type, init_expr, opt_expr)   \
+    {                                                              \
+        using namespace test;                                      \
+        const toml::toml_type init init_expr ;                     \
+        toml::toml_type opt  opt_expr ;                            \
+        value_type v{{"key", init}};                               \
+        BOOST_TEST(init != opt);                                   \
+        const auto moved = toml::find_or(std::move(v), "key", std::move(opt));\
+        BOOST_TEST(init == moved);                                 \
+    }                                                              \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_move, value_type, test_value_types)
+{
+    TOML11_TEST_FIND_OR_MOVE(boolean,         ( true), (false))
+    TOML11_TEST_FIND_OR_MOVE(integer,         (   42), (   54))
+    TOML11_TEST_FIND_OR_MOVE(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_FIND_OR_MOVE(string,          ("foo"), ("bar"))
+    TOML11_TEST_FIND_OR_MOVE(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_FIND_OR_MOVE(local_date,      (2019, toml::month_t::Apr, 1),
+                                              (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_FIND_OR_MOVE(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_FIND_OR_MOVE(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        typename value_type::array_type init{1,2,3,4,5};
+        typename value_type::array_type opt {6,7,8,9,10};
+        value_type v{{"key", init}};
+        BOOST_TEST(init != opt);
+        const auto moved = toml::find_or(std::move(v), "key", std::move(opt));
+        BOOST_TEST(init == moved);
+    }
+    {
+        typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        typename value_type::table_type opt {{"key1", 54}, {"key2", "bar"}};
+        value_type v{{"key", init}};
+        BOOST_TEST(init != opt);
+        const auto moved = toml::find_or(std::move(v), "key", std::move(opt));
+        BOOST_TEST(init == moved);
+    }
+}
+#undef TOML11_TEST_FIND_OR_MOVE
+
+
+#define TOML11_TEST_FIND_OR_MODIFY(toml_type, init_expr, opt_expr)\
+    {                                                             \
+        using namespace test;                                     \
+        const toml::toml_type init init_expr ;                    \
+        toml::toml_type       opt1 opt_expr ;                     \
+        toml::toml_type       opt2 opt_expr ;                     \
+        value_type v{{"key", init}};                              \
+        BOOST_TEST(init != opt1);                                 \
+        toml::find_or(v, "key", opt2) = opt1;                     \
+        BOOST_TEST(opt1 == toml::find<toml::toml_type>(v, "key"));\
+    }                                                             \
+    /**/
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_modify, value_type, test_value_types)
+{
+    TOML11_TEST_FIND_OR_MODIFY(boolean,         ( true), (false))
+    TOML11_TEST_FIND_OR_MODIFY(integer,         (   42), (   54))
+    TOML11_TEST_FIND_OR_MODIFY(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_FIND_OR_MODIFY(string,          ("foo"), ("bar"))
+    TOML11_TEST_FIND_OR_MODIFY(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_FIND_OR_MODIFY(local_date,      (2019, toml::month_t::Apr, 1),
+                                              (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_FIND_OR_MODIFY(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_FIND_OR_MODIFY(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        typename value_type::array_type init{1,2,3,4,5};
+        typename value_type::array_type opt1{6,7,8,9,10};
+        typename value_type::array_type opt2{6,7,8,9,10};
+        BOOST_TEST(init != opt1);
+        value_type v{{"key", init}};
+        toml::find_or(v, "key", opt2) = opt1;
+        BOOST_TEST(opt1 == toml::find<typename value_type::array_type>(v, "key"));
+    }
+    {
+        typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        typename value_type::table_type opt1{{"key1", 54}, {"key2", "bar"}};
+        typename value_type::table_type opt2{{"key1", 54}, {"key2", "bar"}};
+        value_type v{{"key", init}};
+        BOOST_TEST(init != opt1);
+        toml::find_or(v, "key", opt2) = opt1;
+        BOOST_TEST(opt1 == toml::find<typename value_type::table_type>(v, "key"));
+    }
+}
+#undef TOML11_TEST_FIND_OR_MODIFY
+
+#define TOML11_TEST_FIND_OR_FALLBACK(init_type, opt_type)         \
+    {                                                             \
+        using namespace test;                                     \
+        value_type v(init_type);                                  \
+        BOOST_TEST(opt_type == toml::find_or(v, "key", opt_type));\
+    }                                                             \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_fallback, value_type, test_value_types)
+{
+    const toml::boolean         boolean        (true);
+    const toml::integer         integer        (42);
+    const toml::floating        floating       (3.14);
+    const toml::string          string         ("foo");
+    const toml::local_time      local_time     (12, 30, 45);
+    const toml::local_date      local_date     (2019, toml::month_t::Apr, 1);
+    const toml::local_datetime  local_datetime (
+            toml::local_date(2019, toml::month_t::Apr, 1),
+            toml::local_time(12, 30, 45));
+    const toml::offset_datetime offset_datetime(
+            toml::local_date(2019, toml::month_t::Apr, 1),
+            toml::local_time(12, 30, 45), toml::time_offset( 9, 0));
+
+    using array_type = typename value_type::array_type;
+    using table_type = typename value_type::table_type;
+    const array_type array{1, 2, 3, 4, 5};
+    const table_type table{{"key1", 42}, {"key2", "foo"}};
+
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(integer, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(integer, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(floating, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(floating, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(string, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(string, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(string, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(string, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(string, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(string, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(string, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(string, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(string, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(array, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(array, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(array, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(array, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(array, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(array, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(array, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(array, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(array, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(table, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(table, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(table, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(table, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(table, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(table, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(table, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(table, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(table, array          );
+}
+#undef TOML11_TEST_FIND_OR_FALLBACK
+
+BOOST_AUTO_TEST_CASE(test_find_or_integer)
+{
+    {
+        toml::value v{{"num", 42}};
+        BOOST_TEST(42u == toml::find_or(v, "num", 0u));
+        BOOST_TEST(0u ==  toml::find_or(v, "foo", 0u));
+    }
+    {
+        toml::value v{{"num", 42}};
+        const auto moved = toml::find_or(std::move(v), "num", 0u);
+        BOOST_TEST(42u == moved);
+    }
+    {
+        toml::value v{{"num", 42}};
+        const auto moved = toml::find_or(std::move(v), "foo", 0u);
+        BOOST_TEST(0u ==  moved);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_find_or_floating)
+{
+    {
+        toml::value v1{{"key", 42}};
+        toml::value v2{{"key", 3.14}};
+        BOOST_TEST(2.71f == toml::find_or(v1, "key", 2.71f));
+        const double ref(3.14);
+        BOOST_TEST(static_cast<float>(ref) == toml::find_or(v2, "key", 2.71f));
+    }
+    {
+        toml::value v1{{"key", 42}};
+        toml::value v2{{"key", 3.14}};
+        const auto moved1 = toml::find_or(std::move(v1), "key", 2.71f);
+        const auto moved2 = toml::find_or(std::move(v2), "key", 2.71f);
+        BOOST_TEST(2.71f == moved1);
+        const double ref(3.14);
+        BOOST_TEST(static_cast<float>(ref) == moved2);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_find_or_string)
+{
+    {
+        toml::value v1 = toml::table{{"key", "foobar"}};
+        toml::value v2 = toml::table{{"key", 42}};
+
+        std::string       s1("bazqux");
+        const std::string s2("bazqux");
+
+        BOOST_TEST("foobar" == toml::find_or(v1, "key", s1));
+        BOOST_TEST("bazqux" == toml::find_or(v2, "key", s1));
+
+        std::string& v1r = toml::find_or(v1, "key", s1);
+        std::string& s1r = toml::find_or(v2, "key", s1);
+
+        BOOST_TEST("foobar" == v1r);
+        BOOST_TEST("bazqux" == s1r);
+
+        BOOST_TEST("foobar" == toml::find_or(v1, "key", s2));
+        BOOST_TEST("bazqux" == toml::find_or(v2, "key", s2));
+
+        BOOST_TEST("foobar" == toml::find_or(std::move(v1), "key", std::move(s1)));
+        s1 = "bazqux"; // restoring moved value
+        BOOST_TEST("bazqux" == toml::find_or(std::move(v2), "key", std::move(s1)));
+    }
+    {
+        toml::value v1 = toml::table{{"key", "foobar"}};
+        toml::value v2 = toml::table{{"key", 42}};
+
+        std::string s1("bazqux");
+
+        const auto moved1 = toml::find_or(std::move(v1), "key", s1);
+        const auto moved2 = toml::find_or(std::move(v2), "key", s1);
+
+        BOOST_TEST("foobar" == moved1);
+        BOOST_TEST("bazqux" == moved2);
+    }
+    {
+        toml::value v1 = toml::table{{"key", "foobar"}};
+        toml::value v2 = toml::table{{"key", 42}};
+
+        std::string s1("bazqux");
+        std::string s2("bazqux");
+
+        const auto moved1 = toml::find_or(std::move(v1), "key", std::move(s1));
+        const auto moved2 = toml::find_or(std::move(v2), "key", std::move(s2));
+
+        BOOST_TEST("foobar" == moved1);
+        BOOST_TEST("bazqux" == moved2);
+    }
+
+    // string literal
+    {
+        toml::value v1 = toml::table{{"key", "foobar"}};
+        toml::value v2 = toml::table{{"key",42}};
+
+        BOOST_TEST("foobar" == toml::find_or(v1, "key", "bazqux"));
+        BOOST_TEST("bazqux" == toml::find_or(v2, "key", "bazqux"));
+
+        const char* lit = "bazqux";
+        BOOST_TEST("foobar" == toml::find_or(v1, "key", lit));
+        BOOST_TEST("bazqux" == toml::find_or(v2, "key", lit));
+    }
+    {
+        toml::value v1 = toml::table{{"key", "foobar"}};
+        toml::value v2 = toml::table{{"key",42}};
+
+        const auto moved1 = toml::find_or(std::move(v1), "key", "bazqux");
+        const auto moved2 = toml::find_or(std::move(v2), "key", "bazqux");
+
+        BOOST_TEST("foobar" == moved1);
+        BOOST_TEST("bazqux" == moved2);
+    }
+    {
+        toml::value v1 = toml::table{{"key", "foobar"}};
+        toml::value v2 = toml::table{{"key",42}};
+
+        const char* lit = "bazqux";
+        const auto moved1 = toml::find_or(std::move(v1), "key", lit);
+        const auto moved2 = toml::find_or(std::move(v2), "key", lit);
+
+        BOOST_TEST("foobar" == moved1);
+        BOOST_TEST("bazqux" == moved2);
+    }
+
+}
+
+BOOST_AUTO_TEST_CASE(test_find_or_map)
+{
+    using map_type = std::map<std::string, std::string>;
+    {
+        const toml::value v1{
+            {"key", {{"key", "value"}}}
+        };
+
+        const auto key  = toml::find_or(v1, "key",  map_type{});
+        const auto key2 = toml::find_or(v1, "key2", map_type{});
+
+        BOOST_TEST(!key.empty());
+        BOOST_TEST(key2.empty());
+
+        BOOST_TEST(key.size()    == 1u);
+        BOOST_TEST(key.at("key") == "value");
+    }
+    {
+        toml::value v1{
+            {"key", {{"key", "value"}}}
+        };
+
+        const auto key  = toml::find_or<map_type>(v1, "key",  map_type{});
+        const auto key2 = toml::find_or<map_type>(v1, "key2", map_type{});
+
+        BOOST_TEST(!key.empty());
+        BOOST_TEST(key2.empty());
+
+        BOOST_TEST(key.size()    == 1u);
+        BOOST_TEST(key.at("key") == "value");
+    }
+
+    {
+        toml::value v1{
+            {"key", {{"key", "value"}}}
+        };
+        toml::value v2(v1);
+
+        const auto key  = toml::find_or(std::move(v1), "key",  map_type{});
+        const auto key2 = toml::find_or(std::move(v2), "key2", map_type{});
+
+        BOOST_TEST(!key.empty());
+        BOOST_TEST(key2.empty());
+
+        BOOST_TEST(key.size()    == 1u);
+        BOOST_TEST(key.at("key") == "value");
+    }
+    {
+        toml::value v1{
+            {"key", {{"key", "value"}}}
+        };
+        toml::value v2(v1);
+
+        const auto key  = toml::find_or<map_type>(std::move(v1), "key",  map_type{});
+        const auto key2 = toml::find_or<map_type>(std::move(v2), "key2", map_type{});
+
+        BOOST_TEST(!key.empty());
+        BOOST_TEST(key2.empty());
+
+        BOOST_TEST(key.size()    == 1u);
+        BOOST_TEST(key.at("key") == "value");
+    }
+}

tests/test_find_or_recursive.cpp

@@ -0,0 +1,393 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+#include <array>
+#include <deque>
+#include <list>
+#include <map>
+#include <tuple>
+#include <unordered_map>
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+#include <string_view>
+#endif
+
+using test_value_types = std::tuple<
+    toml::basic_value<toml::discard_comments>,
+    toml::basic_value<toml::preserve_comments>,
+    toml::basic_value<toml::discard_comments,  std::map, std::deque>,
+    toml::basic_value<toml::preserve_comments, std::map, std::deque>
+>;
+
+namespace test
+{
+template<typename charT, typename traits, typename T, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const std::vector<T, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << i << ' ';}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits, typename T, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const std::deque<T, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << i << ' ';}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits, typename T, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const std::list<T, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << i << ' ';}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits,
+         typename Key, typename Value, typename Comp, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os,
+           const std::map<Key, Value, Comp, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << '{' << i.first << ", " << i.second << "} ";}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits,
+         typename Key, typename Value, typename Hash, typename Eq, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os,
+           const std::unordered_map<Key, Value, Hash, Eq, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << '{' << i.first << ", " << i.second << "} ";}
+    os << ']';
+    return os;
+}
+} // test
+
+#define TOML11_TEST_FIND_OR_EXACT(toml_type, init_expr, opt_expr) \
+    {                                                             \
+        using namespace test;                                     \
+        const toml::toml_type init init_expr ;                    \
+        const toml::toml_type opt  opt_expr ;                     \
+        const value_type v{{"key1", value_type{{"key2", init}} }};\
+        BOOST_TEST(init != opt);                                  \
+        BOOST_TEST(init == toml::find_or(v, "key1", "key2", opt));\
+    }                                                             \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_exact, value_type, test_value_types)
+{
+    TOML11_TEST_FIND_OR_EXACT(boolean,         ( true), (false))
+    TOML11_TEST_FIND_OR_EXACT(integer,         (   42), (   54))
+    TOML11_TEST_FIND_OR_EXACT(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_FIND_OR_EXACT(string,          ("foo"), ("bar"))
+    TOML11_TEST_FIND_OR_EXACT(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_FIND_OR_EXACT(local_date,      (2019, toml::month_t::Apr, 1),
+                                               (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_FIND_OR_EXACT(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_FIND_OR_EXACT(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        const typename value_type::array_type init{1,2,3,4,5};
+        const typename value_type::array_type opt {6,7,8,9,10};
+        const value_type v{{"key", init}};
+        BOOST_TEST(init != opt);
+        BOOST_TEST(init == toml::find_or(v, "key", opt));
+    }
+    {
+        const typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        const typename value_type::table_type opt {{"key1", 54}, {"key2", "bar"}};
+        const value_type v{{"key", init}};
+        BOOST_TEST(init != opt);
+        BOOST_TEST(init == toml::find_or(v, "key", opt));
+    }
+}
+#undef TOML11_TEST_FIND_OR_EXACT
+
+#define TOML11_TEST_FIND_OR_MOVE(toml_type, init_expr, opt_expr)   \
+    {                                                              \
+        using namespace test;                                      \
+        const toml::toml_type init init_expr ;                     \
+        toml::toml_type opt  opt_expr ;                            \
+        value_type v{{"key1", value_type{{"key2", init}} }};       \
+        BOOST_TEST(init != opt);                                   \
+        const auto moved = toml::find_or(std::move(v), "key1", "key2", std::move(opt));\
+        BOOST_TEST(init == moved);                                 \
+    }                                                              \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_move, value_type, test_value_types)
+{
+    TOML11_TEST_FIND_OR_MOVE(boolean,         ( true), (false))
+    TOML11_TEST_FIND_OR_MOVE(integer,         (   42), (   54))
+    TOML11_TEST_FIND_OR_MOVE(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_FIND_OR_MOVE(string,          ("foo"), ("bar"))
+    TOML11_TEST_FIND_OR_MOVE(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_FIND_OR_MOVE(local_date,      (2019, toml::month_t::Apr, 1),
+                                              (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_FIND_OR_MOVE(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_FIND_OR_MOVE(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        typename value_type::array_type init{1,2,3,4,5};
+        typename value_type::array_type opt {6,7,8,9,10};
+        value_type v{{"key", init}};
+        BOOST_TEST(init != opt);
+        const auto moved = toml::find_or(std::move(v), "key", std::move(opt));
+        BOOST_TEST(init == moved);
+    }
+    {
+        typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        typename value_type::table_type opt {{"key1", 54}, {"key2", "bar"}};
+        value_type v{{"key", init}};
+        BOOST_TEST(init != opt);
+        const auto moved = toml::find_or(std::move(v), "key", std::move(opt));
+        BOOST_TEST(init == moved);
+    }
+}
+#undef TOML11_TEST_FIND_OR_MOVE
+
+
+#define TOML11_TEST_FIND_OR_MODIFY(toml_type, init_expr, opt_expr)\
+    {                                                             \
+        using namespace test;                                     \
+        const toml::toml_type init init_expr ;                    \
+        toml::toml_type       opt1 opt_expr ;                     \
+        toml::toml_type       opt2 opt_expr ;                     \
+        value_type v{{"key1", value_type{{"key2", init}} }};      \
+        BOOST_TEST(init != opt1);                                 \
+        toml::find_or(v, "key1", "key2", opt2) = opt1;            \
+        BOOST_TEST(opt1 == toml::find<toml::toml_type>(v, "key1", "key2"));\
+    }                                                             \
+    /**/
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_modify, value_type, test_value_types)
+{
+    TOML11_TEST_FIND_OR_MODIFY(boolean,         ( true), (false))
+    TOML11_TEST_FIND_OR_MODIFY(integer,         (   42), (   54))
+    TOML11_TEST_FIND_OR_MODIFY(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_FIND_OR_MODIFY(string,          ("foo"), ("bar"))
+    TOML11_TEST_FIND_OR_MODIFY(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_FIND_OR_MODIFY(local_date,      (2019, toml::month_t::Apr, 1),
+                                              (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_FIND_OR_MODIFY(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_FIND_OR_MODIFY(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        typename value_type::array_type init{1,2,3,4,5};
+        typename value_type::array_type opt1{6,7,8,9,10};
+        typename value_type::array_type opt2{6,7,8,9,10};
+        BOOST_TEST(init != opt1);
+        value_type v{{"key", init}};
+        toml::find_or(v, "key", opt2) = opt1;
+        BOOST_TEST(opt1 == toml::find<typename value_type::array_type>(v, "key"));
+    }
+    {
+        typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        typename value_type::table_type opt1{{"key1", 54}, {"key2", "bar"}};
+        typename value_type::table_type opt2{{"key1", 54}, {"key2", "bar"}};
+        value_type v{{"key", init}};
+        BOOST_TEST(init != opt1);
+        toml::find_or(v, "key", opt2) = opt1;
+        BOOST_TEST(opt1 == toml::find<typename value_type::table_type>(v, "key"));
+    }
+}
+#undef TOML11_TEST_FIND_OR_MODIFY
+
+#define TOML11_TEST_FIND_OR_FALLBACK(init_type, opt_type)                   \
+    {                                                                       \
+        using namespace test;                                               \
+        value_type v1{{"key1", value_type{{"key3", "foo"}}}};               \
+        BOOST_TEST(opt_type == toml::find_or(v1, "key1", "key2", opt_type));\
+        value_type v2{{"key1", "foo"}};                                     \
+        BOOST_TEST(opt_type == toml::find_or(v2, "key1", "key3", opt_type));\
+    }                                                                       \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_fallback, value_type, test_value_types)
+{
+    const toml::boolean         boolean        (true);
+    const toml::integer         integer        (42);
+    const toml::floating        floating       (3.14);
+    const toml::string          string         ("foo");
+    const toml::local_time      local_time     (12, 30, 45);
+    const toml::local_date      local_date     (2019, toml::month_t::Apr, 1);
+    const toml::local_datetime  local_datetime (
+            toml::local_date(2019, toml::month_t::Apr, 1),
+            toml::local_time(12, 30, 45));
+    const toml::offset_datetime offset_datetime(
+            toml::local_date(2019, toml::month_t::Apr, 1),
+            toml::local_time(12, 30, 45), toml::time_offset( 9, 0));
+
+    using array_type = typename value_type::array_type;
+    using table_type = typename value_type::table_type;
+    const array_type array{1, 2, 3, 4, 5};
+    const table_type table{{"key1", 42}, {"key2", "foo"}};
+
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(boolean, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(integer, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(integer, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(integer, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(floating, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(floating, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(floating, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(string, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(string, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(string, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(string, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(string, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(string, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(string, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(string, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(string, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(local_time, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(local_date, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(local_datetime, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, array          );
+    TOML11_TEST_FIND_OR_FALLBACK(offset_datetime, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(array, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(array, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(array, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(array, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(array, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(array, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(array, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(array, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(array, table          );
+
+    TOML11_TEST_FIND_OR_FALLBACK(table, boolean        );
+    TOML11_TEST_FIND_OR_FALLBACK(table, integer        );
+    TOML11_TEST_FIND_OR_FALLBACK(table, floating       );
+    TOML11_TEST_FIND_OR_FALLBACK(table, string         );
+    TOML11_TEST_FIND_OR_FALLBACK(table, local_time     );
+    TOML11_TEST_FIND_OR_FALLBACK(table, local_date     );
+    TOML11_TEST_FIND_OR_FALLBACK(table, local_datetime );
+    TOML11_TEST_FIND_OR_FALLBACK(table, offset_datetime);
+    TOML11_TEST_FIND_OR_FALLBACK(table, array          );
+}
+#undef TOML11_TEST_FIND_OR_FALLBACK
+
+struct move_only_type
+{
+    explicit move_only_type(const std::string& n): name_(n) {}
+
+    void from_toml(const toml::value& v)
+    {
+        this->name_ = toml::find<std::string>(v, "name");
+        return;
+    }
+
+    move_only_type(): name_("default"){}
+    ~move_only_type() = default;
+    move_only_type(move_only_type&&)            = default;
+    move_only_type& operator=(move_only_type&&) = default;
+    move_only_type(const move_only_type&)            = delete;
+    move_only_type& operator=(const move_only_type&) = delete;
+
+    bool operator==(const move_only_type& other) const noexcept {return this->name_ == other.name_;}
+    bool operator!=(const move_only_type& other) const noexcept {return this->name_ != other.name_;}
+    bool operator< (const move_only_type& other) const noexcept {return this->name_ <  other.name_;}
+    bool operator<=(const move_only_type& other) const noexcept {return this->name_ <= other.name_;}
+    bool operator> (const move_only_type& other) const noexcept {return this->name_ >  other.name_;}
+    bool operator>=(const move_only_type& other) const noexcept {return this->name_ >= other.name_;}
+
+    std::string name_;
+};
+
+std::ostream& operator<<(std::ostream& os, const move_only_type& mot)
+{
+    os << mot.name_;
+    return os;
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_move_only, value_type, test_value_types)
+{
+    const move_only_type ref("reference");
+    move_only_type opt("optional");
+    {
+        const value_type v{{"key1", value_type{{"key2", value_type{{"name", "reference"}} }} }};
+        BOOST_TEST(ref == toml::find_or(v, "key1", "key2", std::move(opt)));
+    }
+}

tests/test_format_error.cpp

@@ -0,0 +1,72 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+#include <iostream>
+
+// to check it successfully compiles. it does not check the formatted string.
+
+BOOST_AUTO_TEST_CASE(test_1_value)
+{
+    toml::value val(42);
+
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error", val, "this is a value");
+        std::cout << pretty_error << std::endl;
+    }
+
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error", val, "this is a value",
+                               {"this is a hint"});
+        std::cout << pretty_error << std::endl;
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_2_values)
+{
+    toml::value v1(42);
+    toml::value v2(3.14);
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error with two values",
+                               v1, "this is the answer",
+                               v2, "this is the pi");
+        std::cout << pretty_error << std::endl;
+    }
+
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error with two values",
+                               v1, "this is the answer",
+                               v2, "this is the pi",
+                               {"hint"});
+        std::cout << pretty_error << std::endl;
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_3_values)
+{
+    toml::value v1(42);
+    toml::value v2(3.14);
+    toml::value v3("foo");
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error with two values",
+                               v1, "this is the answer",
+                               v2, "this is the pi",
+                               v3, "this is a meta-syntactic variable");
+        std::cout << pretty_error << std::endl;
+    }
+
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error with two values",
+                               v1, "this is the answer",
+                               v2, "this is the pi",
+                               v3, "this is a meta-syntactic variable",
+                               {"hint 1", "hint 2"});
+        std::cout << pretty_error << std::endl;
+    }
+}

tests/test_from_toml.cpp

@@ -1,63 +0,0 @@
-#define BOOST_TEST_MODULE "test_from_toml"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
-#include <toml.hpp>
-#include <map>
-#include <unordered_map>
-#include <list>
-#include <deque>
-#include <array>
-
-BOOST_AUTO_TEST_CASE(test_from_toml)
-{
-    toml::boolean    b = false;
-    toml::integer    i = 0;
-    toml::floating   f = 0.;
-    toml::string     s;
-    toml::local_date dt;
-    toml::array      a;
-    toml::table      t;
-    {
-        toml::value v(true);
-        toml::from_toml(std::tie(b, i, f, s, dt, a, t), v);
-        BOOST_CHECK_EQUAL(b, true);
-    }
-    {
-        toml::value v(42);
-        toml::from_toml(std::tie(b, i, f, s, dt, a, t), v);
-        BOOST_CHECK_EQUAL(i, 42);
-    }
-    {
-        toml::value v(3.14);
-        toml::from_toml(std::tie(b, i, f, s, dt, a, t), v);
-        BOOST_CHECK_EQUAL(f, 3.14);
-    }
-    {
-        toml::value v("foo");
-
-        toml::from_toml(std::tie(b, i, f, s, dt, a, t), v);
-        BOOST_CHECK_EQUAL(s, "foo");
-    }
-    {
-        toml::value v(toml::local_date(2018, toml::month_t::Apr, 22));
-        toml::from_toml(std::tie(b, i, f, s, dt, a, t), v);
-        BOOST_CHECK(dt == toml::local_date(2018, toml::month_t::Apr, 22));
-    }
-    {
-        toml::array ref{toml::value(42), toml::value(54)};
-        toml::value v(ref);
-        toml::from_toml(std::tie(b, i, f, s, dt, a, t), v);
-        BOOST_CHECK(ref == a);
-    }
-    {
-        toml::table ref{{"key1", 42}, {"key2", 3.14}};
-        toml::value v(ref);
-        toml::from_toml(std::tie(b, i, f, s, dt, a, t), v);
-        BOOST_CHECK(ref == t);
-    }
-}
-

tests/test_get.cpp

@@ -1,284 +1,415 @@
-#define BOOST_TEST_MODULE "test_get"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
-#include <toml/value.hpp>
-#include <toml/get.hpp>
-#include <map>
-#include <unordered_map>
-#include <list>
-#include <deque>
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
 #include <array>
+#include <deque>
+#include <list>
+#include <map>
+#include <tuple>
+#include <unordered_map>
 
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+#include <string_view>
+#endif
 
-BOOST_AUTO_TEST_CASE(test_get_exact)
+using test_value_types = std::tuple<
+    toml::basic_value<toml::discard_comments>,
+    toml::basic_value<toml::preserve_comments>,
+    toml::basic_value<toml::discard_comments,  std::map, std::deque>,
+    toml::basic_value<toml::preserve_comments, std::map, std::deque>
+>;
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
 {
     {
-        toml::value v(true);
-        BOOST_CHECK_EQUAL(true, toml::get<toml::boolean>(v));
+        value_type v(true);
+        BOOST_TEST(true == toml::get<toml::boolean>(v));
 
         toml::get<toml::boolean>(v) = false;
-        BOOST_CHECK_EQUAL(false, toml::get<toml::boolean>(v));
+        BOOST_TEST(false == toml::get<toml::boolean>(v));
+
+        toml::boolean x = toml::get<toml::boolean>(std::move(v));
+        BOOST_TEST(false == x);
     }
     {
-        toml::value v(42);
-        BOOST_CHECK_EQUAL(toml::integer(42), toml::get<toml::integer>(v));
+        value_type v(42);
+        BOOST_TEST(toml::integer(42) == toml::get<toml::integer>(v));
 
         toml::get<toml::integer>(v) = 54;
-        BOOST_CHECK_EQUAL(toml::integer(54), toml::get<toml::integer>(v));
+        BOOST_TEST(toml::integer(54) == toml::get<toml::integer>(v));
+
+        toml::integer x = toml::get<toml::integer>(std::move(v));
+        BOOST_TEST(toml::integer(54) == x);
     }
     {
-        toml::value v(3.14);
-        BOOST_CHECK_EQUAL(toml::floating(3.14), toml::get<toml::floating>(v));
+        value_type v(3.14);
+        BOOST_TEST(toml::floating(3.14) == toml::get<toml::floating>(v));
 
         toml::get<toml::floating>(v) = 2.71;
-        BOOST_CHECK_EQUAL(toml::floating(2.71), toml::get<toml::floating>(v));
+        BOOST_TEST(toml::floating(2.71) == toml::get<toml::floating>(v));
+
+        toml::floating x = toml::get<toml::floating>(std::move(v));
+        BOOST_TEST(toml::floating(2.71) == x);
     }
     {
-        toml::value v("foo");
-        BOOST_CHECK_EQUAL(toml::string("foo", toml::string_t::basic),
+        value_type v("foo");
+        BOOST_TEST(toml::string("foo", toml::string_t::basic) ==
                           toml::get<toml::string>(v));
 
         toml::get<toml::string>(v).str += "bar";
-        BOOST_CHECK_EQUAL(toml::string("foobar", toml::string_t::basic),
+        BOOST_TEST(toml::string("foobar", toml::string_t::basic) ==
                           toml::get<toml::string>(v));
+
+        toml::string x = toml::get<toml::string>(std::move(v));
+        BOOST_TEST(toml::string("foobar") == x);
     }
     {
-        toml::value v("foo", toml::string_t::literal);
-        BOOST_CHECK_EQUAL(toml::string("foo", toml::string_t::literal),
+        value_type v("foo", toml::string_t::literal);
+        BOOST_TEST(toml::string("foo", toml::string_t::literal) ==
                           toml::get<toml::string>(v));
 
         toml::get<toml::string>(v).str += "bar";
-        BOOST_CHECK_EQUAL(toml::string("foobar", toml::string_t::literal),
+        BOOST_TEST(toml::string("foobar", toml::string_t::literal) ==
                           toml::get<toml::string>(v));
+
+        toml::string x = toml::get<toml::string>(std::move(v));
+        BOOST_TEST(toml::string("foobar", toml::string_t::literal) == x);
     }
     {
         toml::local_date d(2018, toml::month_t::Apr, 22);
-        toml::value v(d);
-        BOOST_CHECK(d == toml::get<toml::local_date>(v));
+        value_type v(d);
+        BOOST_TEST(d == toml::get<toml::local_date>(v));
 
         toml::get<toml::local_date>(v).year = 2017;
         d.year = 2017;
-        BOOST_CHECK(d == toml::get<toml::local_date>(v));
+        BOOST_TEST(d == toml::get<toml::local_date>(v));
+
+        toml::local_date x = toml::get<toml::local_date>(std::move(v));
+        BOOST_TEST(d == x);
     }
     {
         toml::local_time t(12, 30, 45);
-        toml::value v(t);
-        BOOST_CHECK(t == toml::get<toml::local_time>(v));
+        value_type v(t);
+        BOOST_TEST(t == toml::get<toml::local_time>(v));
 
         toml::get<toml::local_time>(v).hour = 9;
         t.hour = 9;
-        BOOST_CHECK(t == toml::get<toml::local_time>(v));
+        BOOST_TEST(t == toml::get<toml::local_time>(v));
+
+        toml::local_time x = toml::get<toml::local_time>(std::move(v));
+        BOOST_TEST(t == x);
     }
     {
         toml::local_datetime dt(toml::local_date(2018, toml::month_t::Apr, 22),
                                 toml::local_time(12, 30, 45));
-        toml::value v(dt);
-        BOOST_CHECK(dt == toml::get<toml::local_datetime>(v));
+        value_type v(dt);
+        BOOST_TEST(dt == toml::get<toml::local_datetime>(v));
 
         toml::get<toml::local_datetime>(v).date.year = 2017;
         dt.date.year = 2017;
-        BOOST_CHECK(dt == toml::get<toml::local_datetime>(v));
+        BOOST_TEST(dt == toml::get<toml::local_datetime>(v));
+
+        toml::local_datetime x = toml::get<toml::local_datetime>(std::move(v));
+        BOOST_TEST(dt == x);
     }
     {
         toml::offset_datetime dt(toml::local_datetime(
                     toml::local_date(2018, toml::month_t::Apr, 22),
                     toml::local_time(12, 30, 45)), toml::time_offset(9, 0));
-        toml::value v(dt);
-        BOOST_CHECK(dt == toml::get<toml::offset_datetime>(v));
+        value_type v(dt);
+        BOOST_TEST(dt == toml::get<toml::offset_datetime>(v));
 
         toml::get<toml::offset_datetime>(v).date.year = 2017;
         dt.date.year = 2017;
-        BOOST_CHECK(dt == toml::get<toml::offset_datetime>(v));
+        BOOST_TEST(dt == toml::get<toml::offset_datetime>(v));
+
+        toml::offset_datetime x = toml::get<toml::offset_datetime>(std::move(v));
+        BOOST_TEST(dt == x);
     }
     {
-        toml::array vec;
-        vec.push_back(toml::value(42));
-        vec.push_back(toml::value(54));
-        toml::value v(vec);
-        BOOST_CHECK(vec == toml::get<toml::array>(v));
+        using array_type = typename value_type::array_type;
+        array_type vec;
+        vec.push_back(value_type(42));
+        vec.push_back(value_type(54));
+        value_type v(vec);
+        BOOST_TEST(vec == toml::get<array_type>(v));
 
-        toml::get<toml::array>(v).push_back(toml::value(123));
-        vec.push_back(toml::value(123));
-        BOOST_CHECK(vec == toml::get<toml::array>(v));
+        toml::get<array_type>(v).push_back(value_type(123));
+        vec.push_back(value_type(123));
+        BOOST_TEST(vec == toml::get<array_type>(v));
+
+        array_type x = toml::get<array_type>(std::move(v));
+        BOOST_TEST(vec == x);
     }
     {
-        toml::table tab;
-        tab["key1"] = toml::value(42);
-        tab["key2"] = toml::value(3.14);
-        toml::value v(tab);
-        BOOST_CHECK(tab == toml::get<toml::table>(v));
+        using table_type = typename value_type::table_type;
+        table_type tab;
+        tab["key1"] = value_type(42);
+        tab["key2"] = value_type(3.14);
+        value_type v(tab);
+        BOOST_TEST(tab == toml::get<table_type>(v));
 
-        toml::get<toml::table>(v)["key3"] = toml::value(123);
-        tab["key3"] = toml::value(123);
-        BOOST_CHECK(tab == toml::get<toml::table>(v));
+        toml::get<table_type>(v)["key3"] = value_type(123);
+        tab["key3"] = value_type(123);
+        BOOST_TEST(tab == toml::get<table_type>(v));
+
+        table_type x = toml::get<table_type>(std::move(v));
+        BOOST_TEST(tab == x);
     }
     {
-        toml::value v1(42);
-        BOOST_CHECK(v1 == toml::get<toml::value>(v1));
+        value_type v1(42);
+        BOOST_TEST(v1 == toml::get<value_type>(v1));
 
-        toml::value v2(54);
-        toml::get<toml::value>(v1) = v2;
-        BOOST_CHECK(v2 == toml::get<toml::value>(v1));
+        value_type v2(54);
+        toml::get<value_type>(v1) = v2;
+        BOOST_TEST(v2 == toml::get<value_type>(v1));
+
+        value_type x = toml::get<value_type>(std::move(v1));
+        BOOST_TEST(v2 == x);
     }
 }
 
-BOOST_AUTO_TEST_CASE(test_get_integer_type)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_integer_type, value_type, test_value_types)
 {
     {
-        toml::value v(42);
-        BOOST_CHECK_EQUAL(int(42),           toml::get<int          >(v));
-        BOOST_CHECK_EQUAL(short(42),         toml::get<short        >(v));
-        BOOST_CHECK_EQUAL(char(42),          toml::get<char         >(v));
-        BOOST_CHECK_EQUAL(unsigned(42),      toml::get<unsigned     >(v));
-        BOOST_CHECK_EQUAL(long(42),          toml::get<long         >(v));
-        BOOST_CHECK_EQUAL(std::int64_t(42),  toml::get<std::int64_t >(v));
-        BOOST_CHECK_EQUAL(std::uint64_t(42), toml::get<std::uint64_t>(v));
-        BOOST_CHECK_EQUAL(std::int16_t(42),  toml::get<std::int16_t >(v));
-        BOOST_CHECK_EQUAL(std::uint16_t(42), toml::get<std::uint16_t>(v));
+        value_type v(42);
+        BOOST_TEST(int(42) ==           toml::get<int          >(v));
+        BOOST_TEST(short(42) ==         toml::get<short        >(v));
+        BOOST_TEST(char(42) ==          toml::get<char         >(v));
+        BOOST_TEST(unsigned(42) ==      toml::get<unsigned     >(v));
+        BOOST_TEST(long(42) ==          toml::get<long         >(v));
+        BOOST_TEST(std::int64_t(42) ==  toml::get<std::int64_t >(v));
+        BOOST_TEST(std::uint64_t(42) == toml::get<std::uint64_t>(v));
+        BOOST_TEST(std::int16_t(42) ==  toml::get<std::int16_t >(v));
+        BOOST_TEST(std::uint16_t(42) == toml::get<std::uint16_t>(v));
+
+        BOOST_TEST(std::uint16_t(42) == toml::get<std::uint16_t>(std::move(v)));
     }
 }
 
-BOOST_AUTO_TEST_CASE(test_get_floating_type)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_floating_type, value_type, test_value_types)
 {
     {
-        toml::value v(3.14);
-        BOOST_CHECK_EQUAL(static_cast<float      >(3.14), toml::get<float      >(v));
-        BOOST_CHECK_EQUAL(static_cast<double     >(3.14), toml::get<double     >(v));
-        BOOST_CHECK_EQUAL(static_cast<long double>(3.14), toml::get<long double>(v));
+        value_type v(3.14);
+        const double ref(3.14);
+        BOOST_TEST(static_cast<float      >(ref) == toml::get<float      >(v));
+        BOOST_TEST(                         ref  == toml::get<double     >(v));
+        BOOST_TEST(static_cast<long double>(ref) == toml::get<long double>(v));
+        BOOST_TEST(static_cast<float      >(ref) == toml::get<float>(std::move(v)));
     }
 }
 
-BOOST_AUTO_TEST_CASE(test_get_string_type)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_string_type, value_type, test_value_types)
 {
     {
-        toml::value v("foo", toml::string_t::basic);
-        BOOST_CHECK_EQUAL("foo", toml::get<std::string>(v));
+        value_type v("foo", toml::string_t::basic);
+        BOOST_TEST("foo" == toml::get<std::string>(v));
         toml::get<std::string>(v) += "bar";
-        BOOST_CHECK_EQUAL("foobar", toml::get<std::string>(v));
+        BOOST_TEST("foobar" == toml::get<std::string>(v));
+
+        const auto x = toml::get<std::string>(std::move(v));
+        BOOST_TEST("foobar" == x);
     }
     {
-        toml::value v("foo", toml::string_t::literal);
-        BOOST_CHECK_EQUAL("foo", toml::get<std::string>(v));
+        value_type v("foo", toml::string_t::literal);
+        BOOST_TEST("foo" == toml::get<std::string>(v));
         toml::get<std::string>(v) += "bar";
-        BOOST_CHECK_EQUAL("foobar", toml::get<std::string>(v));
+        BOOST_TEST("foobar" == toml::get<std::string>(v));
+
+        const auto x = toml::get<std::string>(std::move(v));
+        BOOST_TEST("foobar" == x);
+    }
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+    {
+        value_type v("foo", toml::string_t::basic);
+        BOOST_TEST("foo" == toml::get<std::string_view>(v));
+    }
+    {
+        value_type v("foo", toml::string_t::literal);
+        BOOST_TEST("foo" == toml::get<std::string_view>(v));
+    }
+#endif
+}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_array, value_type, test_value_types)
+{
+    {
+        const value_type v{42, 54, 69, 72};
+
+        const std::vector<int>         vec = toml::get<std::vector<int>>(v);
+        const std::list<short>         lst = toml::get<std::list<short>>(v);
+        const std::deque<std::int64_t> deq = toml::get<std::deque<std::int64_t>>(v);
+
+        BOOST_TEST(42 == vec.at(0));
+        BOOST_TEST(54 == vec.at(1));
+        BOOST_TEST(69 == vec.at(2));
+        BOOST_TEST(72 == vec.at(3));
+
+        std::list<short>::const_iterator iter = lst.begin();
+        BOOST_TEST(static_cast<short>(42) == *(iter++));
+        BOOST_TEST(static_cast<short>(54) == *(iter++));
+        BOOST_TEST(static_cast<short>(69) == *(iter++));
+        BOOST_TEST(static_cast<short>(72) == *(iter++));
+
+        BOOST_TEST(static_cast<std::int64_t>(42) == deq.at(0));
+        BOOST_TEST(static_cast<std::int64_t>(54) == deq.at(1));
+        BOOST_TEST(static_cast<std::int64_t>(69) == deq.at(2));
+        BOOST_TEST(static_cast<std::int64_t>(72) == deq.at(3));
+
+        std::array<int, 4> ary = toml::get<std::array<int, 4>>(v);
+        BOOST_TEST(42 == ary.at(0));
+        BOOST_TEST(54 == ary.at(1));
+        BOOST_TEST(69 == ary.at(2));
+        BOOST_TEST(72 == ary.at(3));
+
+        std::tuple<int, short, unsigned, long> tpl =
+            toml::get<std::tuple<int, short, unsigned, long>>(v);
+        BOOST_TEST(                      42  == std::get<0>(tpl));
+        BOOST_TEST(static_cast<short   >(54) == std::get<1>(tpl));
+        BOOST_TEST(static_cast<unsigned>(69) == std::get<2>(tpl));
+        BOOST_TEST(static_cast<long    >(72) == std::get<3>(tpl));
+
+        const value_type p{3.14, 2.71};
+        std::pair<double, double> pr = toml::get<std::pair<double, double> >(p);
+        BOOST_TEST(3.14 == pr.first);
+        BOOST_TEST(2.71 == pr.second);
+    }
+
+    {
+        value_type v{42, 54, 69, 72};
+        const std::vector<int> vec = toml::get<std::vector<int>>(std::move(v));
+        BOOST_TEST(42 == vec.at(0));
+        BOOST_TEST(54 == vec.at(1));
+        BOOST_TEST(69 == vec.at(2));
+        BOOST_TEST(72 == vec.at(3));
+    }
+    {
+        value_type v{42, 54, 69, 72};
+        const std::deque<int> deq = toml::get<std::deque<int>>(std::move(v));
+        BOOST_TEST(42 == deq.at(0));
+        BOOST_TEST(54 == deq.at(1));
+        BOOST_TEST(69 == deq.at(2));
+        BOOST_TEST(72 == deq.at(3));
+    }
+    {
+        value_type v{42, 54, 69, 72};
+        const std::list<int> lst = toml::get<std::list<int>>(std::move(v));
+        std::list<int>::const_iterator iter = lst.begin();
+        BOOST_TEST(42 == *(iter++));
+        BOOST_TEST(54 == *(iter++));
+        BOOST_TEST(69 == *(iter++));
+        BOOST_TEST(72 == *(iter++));
+    }
+    {
+        value_type v{42, 54, 69, 72};
+        std::array<int, 4> ary = toml::get<std::array<int, 4>>(std::move(v));
+        BOOST_TEST(42 == ary.at(0));
+        BOOST_TEST(54 == ary.at(1));
+        BOOST_TEST(69 == ary.at(2));
+        BOOST_TEST(72 == ary.at(3));
+    }
+    {
+        value_type v{42, 54, 69, 72};
+        std::tuple<int, short, unsigned, long> tpl =
+            toml::get<std::tuple<int, short, unsigned, long>>(std::move(v));
+        BOOST_TEST(                      42  == std::get<0>(tpl));
+        BOOST_TEST(static_cast<short   >(54) == std::get<1>(tpl));
+        BOOST_TEST(static_cast<unsigned>(69) == std::get<2>(tpl));
+        BOOST_TEST(static_cast<long    >(72) == std::get<3>(tpl));
     }
 }
 
-BOOST_AUTO_TEST_CASE(test_get_toml_array)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_array_of_array, value_type, test_value_types)
 {
-    toml::value v(toml::array(0));
-    toml::get<toml::array>(v).push_back(toml::value(42));
-    toml::get<toml::array>(v).push_back(toml::value(54));
-    toml::get<toml::array>(v).push_back(toml::value(69));
-    toml::get<toml::array>(v).push_back(toml::value(72));
+    {
+        const value_type v1{42, 54, 69, 72};
+        const value_type v2{"foo", "bar", "baz"};
+        const value_type v{v1, v2};
 
-    const std::vector<int>         vec = toml::get<std::vector<int>>(v);
-    const std::list<short>         lst = toml::get<std::list<short>>(v);
-    const std::deque<std::int64_t> deq = toml::get<std::deque<std::int64_t>>(v);
+        std::pair<std::vector<int>, std::vector<std::string>> p =
+            toml::get<std::pair<std::vector<int>, std::vector<std::string>>>(v);
 
-    BOOST_CHECK_EQUAL(42, vec.at(0));
-    BOOST_CHECK_EQUAL(54, vec.at(1));
-    BOOST_CHECK_EQUAL(69, vec.at(2));
-    BOOST_CHECK_EQUAL(72, vec.at(3));
+        BOOST_TEST(p.first.size() == 4u);
+        BOOST_TEST(p.first.at(0) == 42);
+        BOOST_TEST(p.first.at(1) == 54);
+        BOOST_TEST(p.first.at(2) == 69);
+        BOOST_TEST(p.first.at(3) == 72);
 
-    std::list<short>::const_iterator iter = lst.begin();
-    BOOST_CHECK_EQUAL(static_cast<short>(42), *(iter++));
-    BOOST_CHECK_EQUAL(static_cast<short>(54), *(iter++));
-    BOOST_CHECK_EQUAL(static_cast<short>(69), *(iter++));
-    BOOST_CHECK_EQUAL(static_cast<short>(72), *(iter++));
+        BOOST_TEST(p.second.size() == 3u);
+        BOOST_TEST(p.second.at(0) == "foo");
+        BOOST_TEST(p.second.at(1) == "bar");
+        BOOST_TEST(p.second.at(2) == "baz");
 
-    BOOST_CHECK_EQUAL(static_cast<std::int64_t>(42), deq.at(0));
-    BOOST_CHECK_EQUAL(static_cast<std::int64_t>(54), deq.at(1));
-    BOOST_CHECK_EQUAL(static_cast<std::int64_t>(69), deq.at(2));
-    BOOST_CHECK_EQUAL(static_cast<std::int64_t>(72), deq.at(3));
+        std::tuple<std::vector<int>, std::vector<std::string>> t =
+            toml::get<std::tuple<std::vector<int>, std::vector<std::string>>>(v);
 
-    std::array<int, 4> ary = toml::get<std::array<int, 4>>(v);
-    BOOST_CHECK_EQUAL(static_cast<int>(42), ary.at(0));
-    BOOST_CHECK_EQUAL(static_cast<int>(54), ary.at(1));
-    BOOST_CHECK_EQUAL(static_cast<int>(69), ary.at(2));
-    BOOST_CHECK_EQUAL(static_cast<int>(72), ary.at(3));
+        BOOST_TEST(std::get<0>(t).at(0) == 42);
+        BOOST_TEST(std::get<0>(t).at(1) == 54);
+        BOOST_TEST(std::get<0>(t).at(2) == 69);
+        BOOST_TEST(std::get<0>(t).at(3) == 72);
 
-    std::tuple<int, short, unsigned, long> tpl =
-        toml::get<std::tuple<int, short, unsigned, long>>(v);
-    BOOST_CHECK_EQUAL(static_cast<int     >(42), std::get<0>(tpl));
-    BOOST_CHECK_EQUAL(static_cast<short   >(54), std::get<1>(tpl));
-    BOOST_CHECK_EQUAL(static_cast<unsigned>(69), std::get<2>(tpl));
-    BOOST_CHECK_EQUAL(static_cast<long    >(72), std::get<3>(tpl));
+        BOOST_TEST(std::get<1>(t).at(0) == "foo");
+        BOOST_TEST(std::get<1>(t).at(1) == "bar");
+        BOOST_TEST(std::get<1>(t).at(2) == "baz");
+    }
+    {
+        const value_type v1{42, 54, 69, 72};
+        const value_type v2{"foo", "bar", "baz"};
+        value_type v{v1, v2};
 
-    toml::value p(toml::array{});
-    toml::get<toml::array>(p).push_back(toml::value(3.14));
-    toml::get<toml::array>(p).push_back(toml::value(2.71));
-    std::pair<double, double> pr = toml::get<std::pair<double, double> >(p);
-    BOOST_CHECK_EQUAL(3.14, pr.first);
-    BOOST_CHECK_EQUAL(2.71, pr.second);
+        std::pair<std::vector<int>, std::vector<std::string>> p =
+            toml::get<std::pair<std::vector<int>, std::vector<std::string>>>(std::move(v));
+
+        BOOST_TEST(p.first.size() == 4u);
+        BOOST_TEST(p.first.at(0) == 42);
+        BOOST_TEST(p.first.at(1) == 54);
+        BOOST_TEST(p.first.at(2) == 69);
+        BOOST_TEST(p.first.at(3) == 72);
+
+        BOOST_TEST(p.second.size() == 3u);
+        BOOST_TEST(p.second.at(0) == "foo");
+        BOOST_TEST(p.second.at(1) == "bar");
+        BOOST_TEST(p.second.at(2) == "baz");
+    }
 }
 
-BOOST_AUTO_TEST_CASE(test_get_toml_array_of_array)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_table, value_type, test_value_types)
 {
-    toml::value v1(toml::array{});
-    toml::get<toml::array>(v1).push_back(toml::value(42));
-    toml::get<toml::array>(v1).push_back(toml::value(54));
-    toml::get<toml::array>(v1).push_back(toml::value(69));
-    toml::get<toml::array>(v1).push_back(toml::value(72));
+    {
+        const value_type v1{
+                {"key1", 1},
+                {"key2", 2},
+                {"key3", 3},
+                {"key4", 4}
+            };
 
-    toml::value v2(toml::array{});
-    toml::get<toml::array>(v2).push_back(toml::value("foo"));
-    toml::get<toml::array>(v2).push_back(toml::value("bar"));
-    toml::get<toml::array>(v2).push_back(toml::value("baz"));
+        const auto v = toml::get<std::map<std::string, int>>(v1);
+        BOOST_TEST(v.at("key1") == 1);
+        BOOST_TEST(v.at("key2") == 2);
+        BOOST_TEST(v.at("key3") == 3);
+        BOOST_TEST(v.at("key4") == 4);
+    }
+    {
+        value_type v1{
+                {"key1", 1},
+                {"key2", 2},
+                {"key3", 3},
+                {"key4", 4}
+            };
+        const auto v = toml::get<std::map<std::string, int>>(std::move(v1));
+        BOOST_TEST(v.at("key1") == 1);
+        BOOST_TEST(v.at("key2") == 2);
+        BOOST_TEST(v.at("key3") == 3);
+        BOOST_TEST(v.at("key4") == 4);
+    }
 
-    toml::value v(toml::array(2));
-    toml::get<toml::array>(v).at(0) = v1;
-    toml::get<toml::array>(v).at(1) = v2;
-
-    std::pair<std::vector<int>, std::vector<std::string>> p =
-        toml::get<std::pair<std::vector<int>, std::vector<std::string>>>(v);
-
-    BOOST_CHECK_EQUAL(p.first.at(0), 42);
-    BOOST_CHECK_EQUAL(p.first.at(1), 54);
-    BOOST_CHECK_EQUAL(p.first.at(2), 69);
-    BOOST_CHECK_EQUAL(p.first.at(3), 72);
-
-    BOOST_CHECK_EQUAL(p.second.at(0), "foo");
-    BOOST_CHECK_EQUAL(p.second.at(1), "bar");
-    BOOST_CHECK_EQUAL(p.second.at(2), "baz");
-
-    std::tuple<std::vector<int>, std::vector<std::string>> t =
-        toml::get<std::tuple<std::vector<int>, std::vector<std::string>>>(v);
-
-    BOOST_CHECK_EQUAL(std::get<0>(t).at(0), 42);
-    BOOST_CHECK_EQUAL(std::get<0>(t).at(1), 54);
-    BOOST_CHECK_EQUAL(std::get<0>(t).at(2), 69);
-    BOOST_CHECK_EQUAL(std::get<0>(t).at(3), 72);
-
-    BOOST_CHECK_EQUAL(std::get<1>(t).at(0), "foo");
-    BOOST_CHECK_EQUAL(std::get<1>(t).at(1), "bar");
-    BOOST_CHECK_EQUAL(std::get<1>(t).at(2), "baz");
 }
 
-BOOST_AUTO_TEST_CASE(test_get_toml_table)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_local_date, value_type, test_value_types)
 {
-    toml::value v1(toml::table{
-            {"key1", 1},
-            {"key2", 2},
-            {"key3", 3},
-            {"key4", 4}
-            });
-
-    const auto v = toml::get<std::map<std::string, int>>(v1);
-    BOOST_CHECK_EQUAL(v.at("key1"), 1);
-    BOOST_CHECK_EQUAL(v.at("key2"), 2);
-    BOOST_CHECK_EQUAL(v.at("key3"), 3);
-    BOOST_CHECK_EQUAL(v.at("key4"), 4);
-}
-
-
-BOOST_AUTO_TEST_CASE(test_get_toml_local_date)
-{
-    toml::value v1(toml::local_date{2018, toml::month_t::Apr, 1});
+    value_type v1(toml::local_date{2018, toml::month_t::Apr, 1});
     const auto date = std::chrono::system_clock::to_time_t(
             toml::get<std::chrono::system_clock::time_point>(v1));
 
@@ -291,20 +422,22 @@ BOOST_AUTO_TEST_CASE(test_get_toml_local_date)
     t.tm_sec  = 0;
     t.tm_isdst = -1;
     const auto c = std::mktime(&t);
-    BOOST_CHECK_EQUAL(c, date);
+    BOOST_TEST(c == date);
 }
 
-BOOST_AUTO_TEST_CASE(test_get_toml_local_time)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_local_time, value_type, test_value_types)
 {
-    toml::value v1(toml::local_time{12, 30, 45});
+    value_type v1(toml::local_time{12, 30, 45});
     const auto time = toml::get<std::chrono::seconds>(v1);
-    BOOST_CHECK(time == std::chrono::hours(12) +
-                        std::chrono::minutes(30) + std::chrono::seconds(45));
+    const bool result = time == std::chrono::hours(12)   +
+                                std::chrono::minutes(30) +
+                                std::chrono::seconds(45);
+    BOOST_TEST(result);
 }
 
-BOOST_AUTO_TEST_CASE(test_get_toml_local_datetime)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_local_datetime, value_type, test_value_types)
 {
-    toml::value v1(toml::local_datetime(
+    value_type v1(toml::local_datetime(
                 toml::local_date{2018, toml::month_t::Apr, 1},
                 toml::local_time{12, 30, 45}));
 
@@ -319,13 +452,13 @@ BOOST_AUTO_TEST_CASE(test_get_toml_local_datetime)
     t.tm_sec  = 45;
     t.tm_isdst = -1;
     const auto c = std::mktime(&t);
-    BOOST_CHECK_EQUAL(c, date);
+    BOOST_TEST(c == date);
 }
 
-BOOST_AUTO_TEST_CASE(test_get_toml_offset_datetime)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_offset_datetime, value_type, test_value_types)
 {
     {
-    toml::value v1(toml::offset_datetime(
+    value_type v1(toml::offset_datetime(
                 toml::local_date{2018, toml::month_t::Apr, 1},
                 toml::local_time{12, 30, 0},
                 toml::time_offset{9, 0}));
@@ -337,18 +470,18 @@ BOOST_AUTO_TEST_CASE(test_get_toml_offset_datetime)
 
     // get time_t as gmtime (2018-04-01T03:30:00Z)
     const auto tmp = std::gmtime(std::addressof(timet)); // XXX not threadsafe!
-    BOOST_CHECK(tmp);
+    BOOST_TEST(tmp);
     const auto tm = *tmp;
-    BOOST_CHECK_EQUAL(tm.tm_year + 1900, 2018);
-    BOOST_CHECK_EQUAL(tm.tm_mon  + 1,       4);
-    BOOST_CHECK_EQUAL(tm.tm_mday,           1);
-    BOOST_CHECK_EQUAL(tm.tm_hour,           3);
-    BOOST_CHECK_EQUAL(tm.tm_min,           30);
-    BOOST_CHECK_EQUAL(tm.tm_sec,            0);
+    BOOST_TEST(tm.tm_year + 1900 == 2018);
+    BOOST_TEST(tm.tm_mon  + 1 ==       4);
+    BOOST_TEST(tm.tm_mday ==           1);
+    BOOST_TEST(tm.tm_hour ==           3);
+    BOOST_TEST(tm.tm_min ==           30);
+    BOOST_TEST(tm.tm_sec ==            0);
     }
 
     {
-    toml::value v1(toml::offset_datetime(
+    value_type v1(toml::offset_datetime(
                 toml::local_date{2018, toml::month_t::Apr, 1},
                 toml::local_time{12, 30, 0},
                 toml::time_offset{-8, 0}));
@@ -360,14 +493,13 @@ BOOST_AUTO_TEST_CASE(test_get_toml_offset_datetime)
 
     // get time_t as gmtime (2018-04-01T03:30:00Z)
     const auto tmp = std::gmtime(std::addressof(timet)); // XXX not threadsafe!
-    BOOST_CHECK(tmp);
+    BOOST_TEST(tmp);
     const auto tm = *tmp;
-    BOOST_CHECK_EQUAL(tm.tm_year + 1900, 2018);
-    BOOST_CHECK_EQUAL(tm.tm_mon  + 1,       4);
-    BOOST_CHECK_EQUAL(tm.tm_mday,           1);
-    BOOST_CHECK_EQUAL(tm.tm_hour,          20);
-    BOOST_CHECK_EQUAL(tm.tm_min,           30);
-    BOOST_CHECK_EQUAL(tm.tm_sec,            0);
+    BOOST_TEST(tm.tm_year + 1900 == 2018);
+    BOOST_TEST(tm.tm_mon  + 1 ==       4);
+    BOOST_TEST(tm.tm_mday ==           1);
+    BOOST_TEST(tm.tm_hour ==          20);
+    BOOST_TEST(tm.tm_min ==           30);
+    BOOST_TEST(tm.tm_sec ==            0);
     }
 }
-

tests/test_get_or.cpp

@@ -0,0 +1,449 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+#include <array>
+#include <deque>
+#include <list>
+#include <map>
+#include <tuple>
+#include <unordered_map>
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+#include <string_view>
+#endif
+
+using test_value_types = std::tuple<
+    toml::basic_value<toml::discard_comments>,
+    toml::basic_value<toml::preserve_comments>,
+    toml::basic_value<toml::discard_comments,  std::map, std::deque>,
+    toml::basic_value<toml::preserve_comments, std::map, std::deque>
+>;
+
+namespace test
+{
+// to compare result values in BOOST_TEST().
+//
+// BOOST_TEST outputs the expected and actual values. Thus it includes the
+// output stream operator inside. To compile it, we need operator<<s for
+// containers to compare.
+template<typename charT, typename traits, typename T, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const std::vector<T, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << i << ' ';}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits, typename T, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const std::deque<T, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << i << ' ';}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits, typename T, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const std::list<T, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << i << ' ';}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits,
+         typename Key, typename Value, typename Comp, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os,
+           const std::map<Key, Value, Comp, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << '{' << i.first << ", " << i.second << "} ";}
+    os << ']';
+    return os;
+}
+template<typename charT, typename traits,
+         typename Key, typename Value, typename Hash, typename Eq, typename Alloc>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os,
+           const std::unordered_map<Key, Value, Hash, Eq, Alloc>& v)
+{
+    os << "[ ";
+    for(const auto& i : v) {os << '{' << i.first << ", " << i.second << "} ";}
+    os << ']';
+    return os;
+}
+} // test
+
+#define TOML11_TEST_GET_OR_EXACT(toml_type, init_expr, opt_expr)\
+    {                                                           \
+        using namespace test;                                   \
+        const toml::toml_type init init_expr ;                  \
+        const toml::toml_type opt  opt_expr ;                   \
+        const value_type v(init);                               \
+        BOOST_TEST(init != opt);                                \
+        BOOST_TEST(init == toml::get_or(v, opt));               \
+    }                                                           \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_or_exact, value_type, test_value_types)
+{
+    TOML11_TEST_GET_OR_EXACT(boolean,         ( true), (false))
+    TOML11_TEST_GET_OR_EXACT(integer,         (   42), (   54))
+    TOML11_TEST_GET_OR_EXACT(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_GET_OR_EXACT(string,          ("foo"), ("bar"))
+    TOML11_TEST_GET_OR_EXACT(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_GET_OR_EXACT(local_date,      (2019, toml::month_t::Apr, 1),
+                                              (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_GET_OR_EXACT(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_GET_OR_EXACT(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        const typename value_type::array_type init{1,2,3,4,5};
+        const typename value_type::array_type opt {6,7,8,9,10};
+        const value_type v(init);
+        BOOST_TEST(init != opt);
+        BOOST_TEST(init == toml::get_or(v, opt));
+    }
+    {
+        const typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        const typename value_type::table_type opt {{"key1", 54}, {"key2", "bar"}};
+        const value_type v(init);
+        BOOST_TEST(init != opt);
+        BOOST_TEST(init == toml::get_or(v, opt));
+    }
+}
+#undef TOML11_TEST_GET_OR_EXACT
+
+#define TOML11_TEST_GET_OR_MOVE_EXACT(toml_type, init_expr, opt_expr)\
+    {                                                                \
+        using namespace test;                                        \
+        const toml::toml_type init init_expr ;                       \
+        toml::toml_type       opt  opt_expr ;                        \
+        value_type v(init);                                          \
+        BOOST_TEST(init != opt);                                     \
+        const auto opt_ = toml::get_or(std::move(v), std::move(opt));\
+        BOOST_TEST(init == opt_);                                    \
+    }                                                                \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_or_move, value_type, test_value_types)
+{
+    TOML11_TEST_GET_OR_MOVE_EXACT(boolean,         ( true), (false))
+    TOML11_TEST_GET_OR_MOVE_EXACT(integer,         (   42), (   54))
+    TOML11_TEST_GET_OR_MOVE_EXACT(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_GET_OR_MOVE_EXACT(string,          ("foo"), ("bar"))
+    TOML11_TEST_GET_OR_MOVE_EXACT(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_GET_OR_MOVE_EXACT(local_date,      (2019, toml::month_t::Apr, 1),
+                                                   (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_GET_OR_MOVE_EXACT(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_GET_OR_MOVE_EXACT(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        const typename value_type::array_type init{1,2,3,4,5};
+        typename value_type::array_type opt {6,7,8,9,10};
+        value_type v(init);
+        BOOST_TEST(init != opt);
+        const auto opt_ = toml::get_or(std::move(v), std::move(opt));
+        BOOST_TEST(init == opt_);
+    }
+    {
+        const typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        typename value_type::table_type opt {{"key1", 54}, {"key2", "bar"}};
+        value_type v(init);
+        BOOST_TEST(init != opt);
+        const auto opt_ = toml::get_or(std::move(v), std::move(opt));
+        BOOST_TEST(init == opt_);
+    }
+}
+#undef TOML11_TEST_GET_OR_MOVE_EXACT
+
+
+#define TOML11_TEST_GET_OR_MODIFY(toml_type, init_expr, opt_expr)\
+    {                                                            \
+        using namespace test;                                    \
+        const toml::toml_type init init_expr ;                   \
+        toml::toml_type       opt1 opt_expr ;                    \
+        toml::toml_type       opt2 opt_expr ;                    \
+        value_type v(init);                                      \
+        BOOST_TEST(init != opt1);                                \
+        toml::get_or(v, opt2) = opt1;                            \
+        BOOST_TEST(opt1 == toml::get<toml::toml_type>(v));       \
+    }                                                            \
+    /**/
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_or_modify, value_type, test_value_types)
+{
+    TOML11_TEST_GET_OR_MODIFY(boolean,         ( true), (false))
+    TOML11_TEST_GET_OR_MODIFY(integer,         (   42), (   54))
+    TOML11_TEST_GET_OR_MODIFY(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_GET_OR_MODIFY(string,          ("foo"), ("bar"))
+    TOML11_TEST_GET_OR_MODIFY(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_GET_OR_MODIFY(local_date,      (2019, toml::month_t::Apr, 1),
+                                              (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_GET_OR_MODIFY(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_GET_OR_MODIFY(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        typename value_type::array_type init{1,2,3,4,5};
+        typename value_type::array_type opt1{6,7,8,9,10};
+        typename value_type::array_type opt2{6,7,8,9,10};
+        BOOST_TEST(init != opt1);
+        value_type v(init);
+        toml::get_or(v, opt2) = opt1;
+        BOOST_TEST(opt1 == toml::get<typename value_type::array_type>(v));
+    }
+    {
+        typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        typename value_type::table_type opt1{{"key1", 54}, {"key2", "bar"}};
+        typename value_type::table_type opt2{{"key1", 54}, {"key2", "bar"}};
+        value_type v(init);
+        BOOST_TEST(init != opt1);
+        toml::get_or(v, opt2) = opt1;
+        BOOST_TEST(opt1 == toml::get<typename value_type::table_type>(v));
+    }
+}
+#undef TOML11_TEST_GET_OR_MODIFY
+
+#define TOML11_TEST_GET_OR_FALLBACK(init_type, opt_type)  \
+    {                                                     \
+        using namespace test;                             \
+        value_type v(init_type);                          \
+        BOOST_TEST(opt_type == toml::get_or(v, opt_type));\
+    }                                                     \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_or_fallback, value_type, test_value_types)
+{
+    const toml::boolean         boolean        (true);
+    const toml::integer         integer        (42);
+    const toml::floating        floating       (3.14);
+    const toml::string          string         ("foo");
+    const toml::local_time      local_time     (12, 30, 45);
+    const toml::local_date      local_date     (2019, toml::month_t::Apr, 1);
+    const toml::local_datetime  local_datetime (
+            toml::local_date(2019, toml::month_t::Apr, 1),
+            toml::local_time(12, 30, 45));
+    const toml::offset_datetime offset_datetime(
+            toml::local_date(2019, toml::month_t::Apr, 1),
+            toml::local_time(12, 30, 45), toml::time_offset( 9, 0));
+
+    using array_type = typename value_type::array_type;
+    using table_type = typename value_type::table_type;
+    const array_type array{1, 2, 3, 4, 5};
+    const table_type table{{"key1", 42}, {"key2", "foo"}};
+
+    TOML11_TEST_GET_OR_FALLBACK(boolean, integer        );
+    TOML11_TEST_GET_OR_FALLBACK(boolean, floating       );
+    TOML11_TEST_GET_OR_FALLBACK(boolean, string         );
+    TOML11_TEST_GET_OR_FALLBACK(boolean, local_time     );
+    TOML11_TEST_GET_OR_FALLBACK(boolean, local_date     );
+    TOML11_TEST_GET_OR_FALLBACK(boolean, local_datetime );
+    TOML11_TEST_GET_OR_FALLBACK(boolean, offset_datetime);
+    TOML11_TEST_GET_OR_FALLBACK(boolean, array          );
+    TOML11_TEST_GET_OR_FALLBACK(boolean, table          );
+
+    TOML11_TEST_GET_OR_FALLBACK(integer, boolean        );
+    TOML11_TEST_GET_OR_FALLBACK(integer, floating       );
+    TOML11_TEST_GET_OR_FALLBACK(integer, string         );
+    TOML11_TEST_GET_OR_FALLBACK(integer, local_time     );
+    TOML11_TEST_GET_OR_FALLBACK(integer, local_date     );
+    TOML11_TEST_GET_OR_FALLBACK(integer, local_datetime );
+    TOML11_TEST_GET_OR_FALLBACK(integer, offset_datetime);
+    TOML11_TEST_GET_OR_FALLBACK(integer, array          );
+    TOML11_TEST_GET_OR_FALLBACK(integer, table          );
+
+    TOML11_TEST_GET_OR_FALLBACK(floating, boolean        );
+    TOML11_TEST_GET_OR_FALLBACK(floating, integer        );
+    TOML11_TEST_GET_OR_FALLBACK(floating, string         );
+    TOML11_TEST_GET_OR_FALLBACK(floating, local_time     );
+    TOML11_TEST_GET_OR_FALLBACK(floating, local_date     );
+    TOML11_TEST_GET_OR_FALLBACK(floating, local_datetime );
+    TOML11_TEST_GET_OR_FALLBACK(floating, offset_datetime);
+    TOML11_TEST_GET_OR_FALLBACK(floating, array          );
+    TOML11_TEST_GET_OR_FALLBACK(floating, table          );
+
+    TOML11_TEST_GET_OR_FALLBACK(string, boolean        );
+    TOML11_TEST_GET_OR_FALLBACK(string, integer        );
+    TOML11_TEST_GET_OR_FALLBACK(string, floating       );
+    TOML11_TEST_GET_OR_FALLBACK(string, local_time     );
+    TOML11_TEST_GET_OR_FALLBACK(string, local_date     );
+    TOML11_TEST_GET_OR_FALLBACK(string, local_datetime );
+    TOML11_TEST_GET_OR_FALLBACK(string, offset_datetime);
+    TOML11_TEST_GET_OR_FALLBACK(string, array          );
+    TOML11_TEST_GET_OR_FALLBACK(string, table          );
+
+    TOML11_TEST_GET_OR_FALLBACK(local_time, boolean        );
+    TOML11_TEST_GET_OR_FALLBACK(local_time, integer        );
+    TOML11_TEST_GET_OR_FALLBACK(local_time, floating       );
+    TOML11_TEST_GET_OR_FALLBACK(local_time, string         );
+    TOML11_TEST_GET_OR_FALLBACK(local_time, local_date     );
+    TOML11_TEST_GET_OR_FALLBACK(local_time, local_datetime );
+    TOML11_TEST_GET_OR_FALLBACK(local_time, offset_datetime);
+    TOML11_TEST_GET_OR_FALLBACK(local_time, array          );
+    TOML11_TEST_GET_OR_FALLBACK(local_time, table          );
+
+    TOML11_TEST_GET_OR_FALLBACK(local_date, boolean        );
+    TOML11_TEST_GET_OR_FALLBACK(local_date, integer        );
+    TOML11_TEST_GET_OR_FALLBACK(local_date, floating       );
+    TOML11_TEST_GET_OR_FALLBACK(local_date, string         );
+    TOML11_TEST_GET_OR_FALLBACK(local_date, local_time     );
+    TOML11_TEST_GET_OR_FALLBACK(local_date, local_datetime );
+    TOML11_TEST_GET_OR_FALLBACK(local_date, offset_datetime);
+    TOML11_TEST_GET_OR_FALLBACK(local_date, array          );
+    TOML11_TEST_GET_OR_FALLBACK(local_date, table          );
+
+    TOML11_TEST_GET_OR_FALLBACK(local_datetime, boolean        );
+    TOML11_TEST_GET_OR_FALLBACK(local_datetime, integer        );
+    TOML11_TEST_GET_OR_FALLBACK(local_datetime, floating       );
+    TOML11_TEST_GET_OR_FALLBACK(local_datetime, string         );
+    TOML11_TEST_GET_OR_FALLBACK(local_datetime, local_time     );
+    TOML11_TEST_GET_OR_FALLBACK(local_datetime, local_date     );
+    TOML11_TEST_GET_OR_FALLBACK(local_datetime, offset_datetime);
+    TOML11_TEST_GET_OR_FALLBACK(local_datetime, array          );
+    TOML11_TEST_GET_OR_FALLBACK(local_datetime, table          );
+
+    TOML11_TEST_GET_OR_FALLBACK(offset_datetime, boolean        );
+    TOML11_TEST_GET_OR_FALLBACK(offset_datetime, integer        );
+    TOML11_TEST_GET_OR_FALLBACK(offset_datetime, floating       );
+    TOML11_TEST_GET_OR_FALLBACK(offset_datetime, string         );
+    TOML11_TEST_GET_OR_FALLBACK(offset_datetime, local_time     );
+    TOML11_TEST_GET_OR_FALLBACK(offset_datetime, local_date     );
+    TOML11_TEST_GET_OR_FALLBACK(offset_datetime, local_datetime );
+    TOML11_TEST_GET_OR_FALLBACK(offset_datetime, array          );
+    TOML11_TEST_GET_OR_FALLBACK(offset_datetime, table          );
+
+    TOML11_TEST_GET_OR_FALLBACK(array, boolean        );
+    TOML11_TEST_GET_OR_FALLBACK(array, integer        );
+    TOML11_TEST_GET_OR_FALLBACK(array, floating       );
+    TOML11_TEST_GET_OR_FALLBACK(array, string         );
+    TOML11_TEST_GET_OR_FALLBACK(array, local_time     );
+    TOML11_TEST_GET_OR_FALLBACK(array, local_date     );
+    TOML11_TEST_GET_OR_FALLBACK(array, local_datetime );
+    TOML11_TEST_GET_OR_FALLBACK(array, offset_datetime);
+    TOML11_TEST_GET_OR_FALLBACK(array, table          );
+
+    TOML11_TEST_GET_OR_FALLBACK(table, boolean        );
+    TOML11_TEST_GET_OR_FALLBACK(table, integer        );
+    TOML11_TEST_GET_OR_FALLBACK(table, floating       );
+    TOML11_TEST_GET_OR_FALLBACK(table, string         );
+    TOML11_TEST_GET_OR_FALLBACK(table, local_time     );
+    TOML11_TEST_GET_OR_FALLBACK(table, local_date     );
+    TOML11_TEST_GET_OR_FALLBACK(table, local_datetime );
+    TOML11_TEST_GET_OR_FALLBACK(table, offset_datetime);
+    TOML11_TEST_GET_OR_FALLBACK(table, array          );
+}
+#undef TOML11_TEST_GET_OR_FALLBACK
+
+BOOST_AUTO_TEST_CASE(test_get_or_integer)
+{
+    {
+        toml::value v1(42);
+        toml::value v2(3.14);
+        BOOST_TEST(42u == toml::get_or(v1, 0u));
+        BOOST_TEST(0u ==  toml::get_or(v2, 0u));
+    }
+    {
+        toml::value v1(42);
+        toml::value v2(3.14);
+        BOOST_TEST(42u == toml::get_or(std::move(v1), 0u));
+        BOOST_TEST(0u ==  toml::get_or(std::move(v2), 0u));
+    }
+
+}
+
+BOOST_AUTO_TEST_CASE(test_get_or_floating)
+{
+    {
+        toml::value v1(42);
+        toml::value v2(3.14);
+        BOOST_TEST(2.71f == toml::get_or(v1, 2.71f));
+        BOOST_TEST(static_cast<float>(v2.as_floating()) == toml::get_or(v2, 2.71f));
+    }
+    {
+        toml::value v1(42);
+        toml::value v2(3.14);
+        BOOST_TEST(2.71f                    == toml::get_or(std::move(v1), 2.71f));
+        BOOST_TEST(static_cast<float>(3.14) == toml::get_or(std::move(v2), 2.71f));
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_get_or_string)
+{
+    {
+        toml::value v1("foobar");
+        toml::value v2(42);
+
+        std::string       s1("bazqux");
+        const std::string s2("bazqux");
+
+        BOOST_TEST("foobar" == toml::get_or(v1, s1));
+        BOOST_TEST("bazqux" == toml::get_or(v2, s1));
+
+        std::string& v1r = toml::get_or(v1, s1);
+        std::string& s1r = toml::get_or(v2, s1);
+
+        BOOST_TEST("foobar" == v1r);
+        BOOST_TEST("bazqux" == s1r);
+
+        BOOST_TEST("foobar" == toml::get_or(v1, s2));
+        BOOST_TEST("bazqux" == toml::get_or(v2, s2));
+
+        BOOST_TEST("foobar" == toml::get_or(v1, std::move(s1)));
+        BOOST_TEST("bazqux" == toml::get_or(v2, std::move(s1)));
+    }
+    {
+        toml::value v1("foobar");
+        toml::value v2(42);
+
+        std::string       s1("bazqux");
+        const std::string s2("bazqux");
+
+        BOOST_TEST("foobar" == toml::get_or(std::move(v1), s1));
+        BOOST_TEST("bazqux" == toml::get_or(std::move(v2), s1));
+    }
+    {
+        toml::value v1("foobar");
+        toml::value v2(42);
+
+        BOOST_TEST("foobar" == toml::get_or(v1, "bazqux"));
+        BOOST_TEST("bazqux" == toml::get_or(v2, "bazqux"));
+
+        const char* lit = "bazqux";
+        BOOST_TEST("foobar" == toml::get_or(v1, lit));
+        BOOST_TEST("bazqux" == toml::get_or(v2, lit));
+    }
+    {
+        toml::value v1("foobar");
+        toml::value v2(42);
+
+        BOOST_TEST("foobar" == toml::get_or(std::move(v1), "bazqux"));
+        BOOST_TEST("bazqux" == toml::get_or(std::move(v2), "bazqux"));
+    }
+    {
+        toml::value v1("foobar");
+        toml::value v2(42);
+
+        const char* lit = "bazqux";
+        BOOST_TEST("foobar" == toml::get_or(v1, lit));
+        BOOST_TEST("bazqux" == toml::get_or(v2, lit));
+    }
+
+}

tests/test_get_related_func.cpp

@@ -1,81 +0,0 @@
-#define BOOST_TEST_MODULE "test_get_or"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
-#include <toml.hpp>
-#include <map>
-#include <unordered_map>
-#include <list>
-#include <deque>
-#include <array>
-
-BOOST_AUTO_TEST_CASE(test_find)
-{
-    {
-        toml::value v(true);
-        bool thrown = false;
-        try
-        {
-            toml::find<toml::boolean>(v, "key");
-        }
-        catch(toml::type_error const& te)
-        {
-            thrown = true;
-        }
-        BOOST_CHECK(thrown);
-    }
-
-    {
-        toml::table v{{"num", 42}};
-        BOOST_CHECK_EQUAL(42, toml::find<int>(v, "num"));
-        toml::find<toml::integer>(v, "num") = 54;
-        BOOST_CHECK_EQUAL(54, toml::find<int>(v, "num"));
-    }
-
-    {
-        toml::value v = toml::table{{"num", 42}};
-        BOOST_CHECK_EQUAL(42, toml::find<int>(v, "num"));
-        toml::find<toml::integer>(v, "num") = 54;
-        BOOST_CHECK_EQUAL(54, toml::find<int>(v, "num"));
-    }
-}
-
-BOOST_AUTO_TEST_CASE(test_get_or)
-{
-    {
-        toml::table v{{"num", 42}};
-        BOOST_CHECK_EQUAL(42, toml::get_or<int>(v, "num", 0));
-        BOOST_CHECK_EQUAL(0,  toml::get_or<int>(v, "foo", 0));
-    }
-    {
-        toml::value v = toml::table{{"num", 42}};
-        BOOST_CHECK_EQUAL(42, toml::get_or<int>(v, "num", 0));
-        BOOST_CHECK_EQUAL(0,  toml::get_or<int>(v, "foo", 0));
-    }
-    {
-        toml::value v1(42);
-        toml::value v2(3.14);
-        BOOST_CHECK_EQUAL(42, toml::get_or<int>(v1, 0));
-        BOOST_CHECK_EQUAL(0,  toml::get_or<int>(v2, 0));
-    }
-}
-
-BOOST_AUTO_TEST_CASE(test_expect)
-{
-    {
-        toml::value v1(42);
-        toml::value v2(3.14);
-        const auto v1_or_0 = toml::expect<int>(v1).unwrap_or(0);
-        const auto v2_or_0 = toml::expect<int>(v2).unwrap_or(0);
-        BOOST_CHECK_EQUAL(42, v1_or_0);
-        BOOST_CHECK_EQUAL( 0, v2_or_0);
-
-        const auto v1_or_none = toml::expect<int>(v1).map([](int i){return std::to_string(i);}).unwrap_or(std::string("none"));
-        const auto v2_or_none = toml::expect<int>(v2).map([](int i){return std::to_string(i);}).unwrap_or(std::string("none"));
-        BOOST_CHECK_EQUAL("42",   v1_or_none);
-        BOOST_CHECK_EQUAL("none", v2_or_none);
-    }
-}

tests/test_lex_aux.hpp

@@ -8,19 +8,19 @@
 do {                                                                           \
     const std::string token   (tkn);                                           \
     const std::string expected(expct);                                         \
-    toml::detail::location<std::string> loc("test", token);                    \
+    toml::detail::location loc("test", token);                                 \
     const auto result = lxr::invoke(loc);                                      \
-    BOOST_CHECK(result.is_ok());                                               \
+    BOOST_TEST(result.is_ok());                                                \
     if(result.is_ok()){                                                        \
-    const auto region = result.unwrap();                                       \
-    BOOST_CHECK_EQUAL(region.str(), expected);                                 \
-    BOOST_CHECK_EQUAL(region.str().size(), expected.size());                   \
-    BOOST_CHECK_EQUAL(static_cast<std::size_t>(std::distance(                  \
-                    loc.begin(), loc.iter())), region.size());                 \
+        const auto region = result.unwrap();                                   \
+        BOOST_TEST(region.str() == expected);                                  \
+        BOOST_TEST(region.str().size() == expected.size());                    \
+        BOOST_TEST(static_cast<std::size_t>(std::distance(                     \
+                        loc.begin(), loc.iter())) == region.size());           \
     } else {                                                                   \
-    std::cerr << "lexer " << lxr::pattern() << " failed with input `";         \
-    std::cerr << token << "`. expected `" << expected << "`\n";                \
-    std::cerr << "reason: " << result.unwrap_err() << '\n';                    \
+        std::cerr << "lexer failed with input `";                              \
+        std::cerr << token << "`. expected `" << expected << "`\n";            \
+        std::cerr << "reason: " << result.unwrap_err() << '\n';                \
     }                                                                          \
 } while(false);                                                                \
 /**/
@@ -28,8 +28,9 @@ do {                                                                           \
 #define TOML11_TEST_LEX_REJECT(lxr, tkn)                                       \
 do {                                                                           \
     const std::string token   (tkn);                                           \
-    toml::detail::location<std::string> loc("test", token);                    \
+    toml::detail::location loc("test", token);                                 \
     const auto result = lxr::invoke(loc);                                      \
-    BOOST_CHECK(result.is_err());                                              \
-    BOOST_CHECK(loc.begin() == loc.iter());                                    \
+    BOOST_TEST(result.is_err());                                               \
+    const bool loc_same = (loc.begin() == loc.iter());                         \
+    BOOST_TEST(loc_same);                                                      \
 } while(false); /**/

tests/test_lex_boolean.cpp

@@ -1,6 +1,6 @@
-#define BOOST_TEST_MODULE "test_lex_boolean"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
 using namespace toml;

tests/test_lex_datetime.cpp

@@ -1,6 +1,6 @@
-#define BOOST_TEST_MODULE "test_lex_datetime"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
 using namespace toml;

tests/test_lex_floating.cpp

@@ -1,9 +1,10 @@
-#define BOOST_TEST_MODULE "test_lex_floating"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
-#include <limits>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
+#include <limits>
+
 using namespace toml;
 using namespace detail;
 
@@ -35,27 +36,35 @@ BOOST_AUTO_TEST_CASE(test_fractional_invalid)
 
 BOOST_AUTO_TEST_CASE(test_exponential_valid)
 {
-    TOML11_TEST_LEX_ACCEPT(lex_float, "1e10",       "1e10");      
-    TOML11_TEST_LEX_ACCEPT(lex_float, "1e+10",      "1e+10");     
-    TOML11_TEST_LEX_ACCEPT(lex_float, "1e-10",      "1e-10");     
-    TOML11_TEST_LEX_ACCEPT(lex_float, "+1e10",      "+1e10");     
-    TOML11_TEST_LEX_ACCEPT(lex_float, "+1e+10",     "+1e+10");    
-    TOML11_TEST_LEX_ACCEPT(lex_float, "+1e-10",     "+1e-10");    
-    TOML11_TEST_LEX_ACCEPT(lex_float, "-1e10",      "-1e10");     
-    TOML11_TEST_LEX_ACCEPT(lex_float, "-1e+10",     "-1e+10");    
-    TOML11_TEST_LEX_ACCEPT(lex_float, "-1e-10",     "-1e-10");    
-    TOML11_TEST_LEX_ACCEPT(lex_float, "123e-10",    "123e-10");   
-    TOML11_TEST_LEX_ACCEPT(lex_float, "1E10",       "1E10");      
-    TOML11_TEST_LEX_ACCEPT(lex_float, "1E+10",      "1E+10");     
-    TOML11_TEST_LEX_ACCEPT(lex_float, "1E-10",      "1E-10");     
-    TOML11_TEST_LEX_ACCEPT(lex_float, "123E-10",    "123E-10");   
-    TOML11_TEST_LEX_ACCEPT(lex_float, "1_2_3E-10",  "1_2_3E-10"); 
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1e10",       "1e10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1e+10",      "1e+10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1e-10",      "1e-10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "+1e10",      "+1e10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "+1e+10",     "+1e+10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "+1e-10",     "+1e-10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "-1e10",      "-1e10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "-1e+10",     "-1e+10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "-1e-10",     "-1e-10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "123e-10",    "123e-10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1E10",       "1E10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1E+10",      "1E+10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1E-10",      "1E-10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "123E-10",    "123E-10");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1_2_3E-10",  "1_2_3E-10");
     TOML11_TEST_LEX_ACCEPT(lex_float, "1_2_3E-1_0", "1_2_3E-1_0");
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1_2_3E-01",  "1_2_3E-01");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1_2_3E-0_1", "1_2_3E-0_1");
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_exponential_invalid)
 {
-    TOML11_TEST_LEX_ACCEPT(lex_float, "1e1E0", "1e1"); 
+    // accept partially
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1e1E0", "1e1");
     TOML11_TEST_LEX_ACCEPT(lex_float, "1E1e0", "1E1");
 }
 
@@ -64,12 +73,26 @@ BOOST_AUTO_TEST_CASE(test_both_valid)
     TOML11_TEST_LEX_ACCEPT(lex_float, "6.02e23",          "6.02e23");
     TOML11_TEST_LEX_ACCEPT(lex_float, "6.02e+23",         "6.02e+23");
     TOML11_TEST_LEX_ACCEPT(lex_float, "1.112_650_06e-17", "1.112_650_06e-17");
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1.0e-07",          "1.0e-07");
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_both_invalid)
 {
-    TOML11_TEST_LEX_ACCEPT(lex_float, "1e1.0",  "1e1");
     TOML11_TEST_LEX_REJECT(lex_float, "01e1.0");
+    // accept partially
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1e1.0",  "1e1");
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1.0e_01",  "1.0");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1.0e0__1", "1.0e0");
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_special_floating_point)

tests/test_lex_integer.cpp

@@ -1,6 +1,6 @@
-#define BOOST_TEST_MODULE "test_lex_integer"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
 using namespace toml;

tests/test_lex_key_comment.cpp

@@ -1,6 +1,6 @@
-#define BOOST_TEST_MODULE "lex_key_comment_test"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
 using namespace toml;
@@ -18,12 +18,11 @@ BOOST_AUTO_TEST_CASE(test_quoted_key)
 {
     TOML11_TEST_LEX_ACCEPT(lex_key, "\"127.0.0.1\"", "\"127.0.0.1\"");
     TOML11_TEST_LEX_ACCEPT(lex_key, "\"character encoding\"", "\"character encoding\"");
-#if defined(_MSC_VER) || defined(__INTEL_COMPILER)
+
+    // UTF-8 codepoint of characters that looks like "key" written upside down
     TOML11_TEST_LEX_ACCEPT(lex_key, "\"\xCA\x8E\xC7\x9D\xCA\x9E\"",
                                     "\"\xCA\x8E\xC7\x9D\xCA\x9E\"");
-#else
-    TOML11_TEST_LEX_ACCEPT(lex_key, u8"\"ʎǝʞ\"", u8"\"ʎǝʞ\"");
-#endif
+
     TOML11_TEST_LEX_ACCEPT(lex_key, "'key2'", "'key2'");
     TOML11_TEST_LEX_ACCEPT(lex_key, "'quoted \"value\"'", "'quoted \"value\"'");
 }

tests/test_lex_string.cpp

@@ -1,6 +1,6 @@
-#define BOOST_TEST_MODULE "test_lex_string"
-#include <boost/test/unit_test.hpp>
 #include <toml/lexer.hpp>
+
+#include "unit_test.hpp"
 #include "test_lex_aux.hpp"
 
 using namespace toml;
@@ -31,15 +31,9 @@ BOOST_AUTO_TEST_CASE(test_basic_string)
             "\"192.168.1.1\"",
             "\"192.168.1.1\"");
 
-#if defined(_MSC_VER) || defined(__INTEL_COMPILER)
     TOML11_TEST_LEX_ACCEPT(lex_string,
-            "\"\xE4\xB8\xAD\xE5\x9B\xBD\"",
-            "\"\xE4\xB8\xAD\xE5\x9B\xBD\"");
-#else
-    TOML11_TEST_LEX_ACCEPT(lex_string,
-            u8"\"中国\"",
-            u8"\"中国\"");
-#endif
+            "\"\xE4\xB8\xAD\xE5\x9B\xBD\"",  // UTF-8 string (means "China" in
+            "\"\xE4\xB8\xAD\xE5\x9B\xBD\""); // Chinese characters)
 
     TOML11_TEST_LEX_ACCEPT(lex_string,
             "\"You'll hate me after this - #\"",
@@ -57,6 +51,22 @@ BOOST_AUTO_TEST_CASE(test_ml_basic_string)
     TOML11_TEST_LEX_ACCEPT(lex_string,
         "\"\"\"\\\n  The quick brown \\\n\n  fox jumps over \\\n  the lazy dog.\\\n  \"\"\"",
         "\"\"\"\\\n  The quick brown \\\n\n  fox jumps over \\\n  the lazy dog.\\\n  \"\"\"");
+
+    TOML11_TEST_LEX_ACCEPT(lex_string,
+        "\"\"\"Here are two quotation marks: \"\". Simple enough.\"\"\"",
+        "\"\"\"Here are two quotation marks: \"\". Simple enough.\"\"\"");
+
+    TOML11_TEST_LEX_ACCEPT(lex_string,
+        "\"\"\"Here are three quotation marks: \"\"\\\".\"\"\"",
+        "\"\"\"Here are three quotation marks: \"\"\\\".\"\"\"");
+
+    TOML11_TEST_LEX_ACCEPT(lex_string,
+        "\"\"\"Here are fifteen quotation marks: \"\"\\\"\"\"\\\"\"\"\\\"\"\"\\\"\"\"\\\".\"\"\"",
+        "\"\"\"Here are fifteen quotation marks: \"\"\\\"\"\"\\\"\"\"\\\"\"\"\\\"\"\"\\\".\"\"\"");
+
+    TOML11_TEST_LEX_ACCEPT(lex_string,
+        "\"\"\"\"This,\" she said, \"is just a pointless statement.\"\"\"\"",
+        "\"\"\"\"This,\" she said, \"is just a pointless statement.\"\"\"\"");
 }
 
 BOOST_AUTO_TEST_CASE(test_literal_string)
@@ -83,4 +93,16 @@ BOOST_AUTO_TEST_CASE(test_ml_literal_string)
     TOML11_TEST_LEX_ACCEPT(lex_string,
         "'''\nThe first newline is\ntrimmed in raw strings.\n   All other whitespace\n   is preserved.\n'''",
         "'''\nThe first newline is\ntrimmed in raw strings.\n   All other whitespace\n   is preserved.\n'''");
+
+    TOML11_TEST_LEX_ACCEPT(lex_string,
+        "''''That's still pointless', she said.'''",
+        "''''That's still pointless', she said.'''");
+
+    TOML11_TEST_LEX_ACCEPT(lex_string,
+        "'''Here are fifteen quotation marks: \"\"\"\"\"\"\"\"\"\"\"\"\"\"\".'''",
+        "'''Here are fifteen quotation marks: \"\"\"\"\"\"\"\"\"\"\"\"\"\"\".'''");
+
+    TOML11_TEST_LEX_ACCEPT(lex_string,
+        "''''This,' she said, 'is just a pointless statement.''''",
+        "''''This,' she said, 'is just a pointless statement.''''");
 }

tests/test_literals.cpp

@@ -0,0 +1,336 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+#include <map>
+
+BOOST_AUTO_TEST_CASE(test_file_as_literal)
+{
+    using namespace toml::literals::toml_literals;
+
+    {
+        const toml::value r{{"a", 42}, {"b", "baz"}};
+        const toml::value v = R"(
+            a = 42
+            b = "baz"
+        )"_toml;
+
+        BOOST_TEST(r == v);
+    }
+    {
+        const toml::value r{
+            {"c", 3.14},
+            {"table", toml::table{{"a", 42}, {"b", "baz"}}}
+        };
+        const toml::value v = R"(
+            c = 3.14
+            [table]
+            a = 42
+            b = "baz"
+        )"_toml;
+
+        BOOST_TEST(r == v);
+    }
+    {
+        const toml::value r{
+            {"table", toml::table{{"a", 42}, {"b", "baz"}}}
+        };
+        const toml::value v = R"(
+            [table]
+            a = 42
+            b = "baz"
+        )"_toml;
+
+        BOOST_TEST(r == v);
+    }
+    {
+        const toml::value r{
+            {"array_of_tables", toml::array{toml::table{}}}
+        };
+        const toml::value v = R"(
+            [[array_of_tables]]
+        )"_toml;
+
+        BOOST_TEST(r == v);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_value_as_literal)
+{
+    using namespace toml::literals::toml_literals;
+
+    {
+        const toml::value v1 = "true"_toml;
+        const toml::value v2 = "false"_toml;
+
+        BOOST_TEST(v1.is_boolean());
+        BOOST_TEST(v2.is_boolean());
+        BOOST_TEST(toml::get<bool>(v1));
+        BOOST_TEST(!toml::get<bool>(v2));
+    }
+    {
+        const toml::value v1 = "123_456"_toml;
+        const toml::value v2 = "0b0010"_toml;
+        const toml::value v3 = "0xDEADBEEF"_toml;
+
+        BOOST_TEST(v1.is_integer());
+        BOOST_TEST(v2.is_integer());
+        BOOST_TEST(v3.is_integer());
+        BOOST_TEST(toml::get<toml::integer>(v1) == 123456);
+        BOOST_TEST(toml::get<toml::integer>(v2) == 2);
+        BOOST_TEST(toml::get<toml::integer>(v3) == 0xDEADBEEF);
+    }
+    {
+        const toml::value v1 = "3.1415"_toml;
+        const toml::value v2 = "6.02e+23"_toml;
+
+        BOOST_TEST(v1.is_floating());
+        BOOST_TEST(v2.is_floating());
+        BOOST_TEST(toml::get<double>(v1) == 3.1415,  boost::test_tools::tolerance(0.00001));
+        BOOST_TEST(toml::get<double>(v2) == 6.02e23, boost::test_tools::tolerance(0.0001));
+    }
+    {
+        const toml::value v1 = R"("foo")"_toml;
+        const toml::value v2 = R"('foo')"_toml;
+        const toml::value v3 = R"("""foo""")"_toml;
+        const toml::value v4 = R"('''foo''')"_toml;
+
+        BOOST_TEST(v1.is_string());
+        BOOST_TEST(v2.is_string());
+        BOOST_TEST(v3.is_string());
+        BOOST_TEST(v4.is_string());
+        BOOST_TEST(toml::get<std::string>(v1) == "foo");
+        BOOST_TEST(toml::get<std::string>(v2) == "foo");
+        BOOST_TEST(toml::get<std::string>(v3) == "foo");
+        BOOST_TEST(toml::get<std::string>(v4) == "foo");
+    }
+    {
+        {
+            const toml::value v1 = R"([1,2,3])"_toml;
+            BOOST_TEST(v1.is_array());
+            const bool result = (toml::get<std::vector<int>>(v1) == std::vector<int>{1,2,3});
+            BOOST_TEST(result);
+        }
+        {
+            const toml::value v2 = R"([1,])"_toml;
+            BOOST_TEST(v2.is_array());
+            const bool result = (toml::get<std::vector<int>>(v2) == std::vector<int>{1});
+            BOOST_TEST(result);
+        }
+        {
+            const toml::value v3 = R"([[1,]])"_toml;
+            BOOST_TEST(v3.is_array());
+            const bool result = (toml::get<std::vector<int>>(toml::get<toml::array>(v3).front()) == std::vector<int>{1});
+            BOOST_TEST(result);
+        }
+        {
+            const toml::value v4 = R"([[1],])"_toml;
+            BOOST_TEST(v4.is_array());
+            const bool result = (toml::get<std::vector<int>>(toml::get<toml::array>(v4).front()) == std::vector<int>{1});
+            BOOST_TEST(result);
+        }
+    }
+    {
+        const toml::value v1 = R"({a = 42})"_toml;
+
+        BOOST_TEST(v1.is_table());
+        const bool result = toml::get<std::map<std::string,int>>(v1) ==
+                               std::map<std::string,int>{{"a", 42}};
+        BOOST_TEST(result);
+    }
+    {
+        const toml::value v1 = "1979-05-27"_toml;
+
+        BOOST_TEST(v1.is_local_date());
+        BOOST_TEST(toml::get<toml::local_date>(v1) ==
+                   toml::local_date(1979, toml::month_t::May, 27));
+    }
+    {
+        const toml::value v1 = "12:00:00"_toml;
+
+        BOOST_TEST(v1.is_local_time());
+        const bool result = toml::get<std::chrono::hours>(v1) == std::chrono::hours(12);
+        BOOST_TEST(result);
+    }
+    {
+        const toml::value v1 = "1979-05-27T07:32:00"_toml;
+        BOOST_TEST(v1.is_local_datetime());
+        BOOST_TEST(toml::get<toml::local_datetime>(v1) ==
+            toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27),
+                                 toml::local_time(7, 32, 0)));
+    }
+    {
+        const toml::value v1 = "1979-05-27T07:32:00Z"_toml;
+        BOOST_TEST(v1.is_offset_datetime());
+        BOOST_TEST(toml::get<toml::offset_datetime>(v1) ==
+            toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
+                                  toml::local_time(7, 32, 0), toml::time_offset(0, 0)));
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_file_as_u8_literal)
+{
+    using namespace toml::literals::toml_literals;
+
+    {
+        const toml::value r{{"a", 42}, {"b", "baz"}};
+        const toml::value v = u8R"(
+            a = 42
+            b = "baz"
+        )"_toml;
+
+        BOOST_TEST(r == v);
+    }
+    {
+        const toml::value r{
+            {"c", 3.14},
+            {"table", toml::table{{"a", 42}, {"b", "baz"}}}
+        };
+        const toml::value v = u8R"(
+            c = 3.14
+            [table]
+            a = 42
+            b = "baz"
+        )"_toml;
+
+        BOOST_TEST(r == v);
+    }
+    {
+        const toml::value r{
+            {"table", toml::table{{"a", 42}, {"b", "baz"}}}
+        };
+        const toml::value v = u8R"(
+            [table]
+            a = 42
+            b = "baz"
+        )"_toml;
+
+        BOOST_TEST(r == v);
+    }
+    {
+        const toml::value r{
+            {"array_of_tables", toml::array{toml::table{}}}
+        };
+        const toml::value v = u8R"(
+            [[array_of_tables]]
+        )"_toml;
+
+        BOOST_TEST(r == v);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_value_as_u8_literal)
+{
+    using namespace toml::literals::toml_literals;
+
+    {
+        const toml::value v1 = u8"true"_toml;
+        const toml::value v2 = u8"false"_toml;
+
+        BOOST_TEST(v1.is_boolean());
+        BOOST_TEST(v2.is_boolean());
+        BOOST_TEST(toml::get<bool>(v1));
+        BOOST_TEST(!toml::get<bool>(v2));
+    }
+    {
+        const toml::value v1 = u8"123_456"_toml;
+        const toml::value v2 = u8"0b0010"_toml;
+        const toml::value v3 = u8"0xDEADBEEF"_toml;
+
+        BOOST_TEST(v1.is_integer());
+        BOOST_TEST(v2.is_integer());
+        BOOST_TEST(v3.is_integer());
+        BOOST_TEST(toml::get<toml::integer>(v1) == 123456);
+        BOOST_TEST(toml::get<toml::integer>(v2) == 2);
+        BOOST_TEST(toml::get<toml::integer>(v3) == 0xDEADBEEF);
+    }
+    {
+        const toml::value v1 = u8"3.1415"_toml;
+        const toml::value v2 = u8"6.02e+23"_toml;
+
+        BOOST_TEST(v1.is_floating());
+        BOOST_TEST(v2.is_floating());
+        BOOST_TEST(toml::get<double>(v1) == 3.1415,  boost::test_tools::tolerance(0.00001));
+        BOOST_TEST(toml::get<double>(v2) == 6.02e23, boost::test_tools::tolerance(0.0001));
+    }
+    {
+        const toml::value v1 = u8R"("foo")"_toml;
+        const toml::value v2 = u8R"('foo')"_toml;
+        const toml::value v3 = u8R"("""foo""")"_toml;
+        const toml::value v4 = u8R"('''foo''')"_toml;
+        const toml::value v5 = u8R"("ひらがな")"_toml;
+
+        BOOST_TEST(v1.is_string());
+        BOOST_TEST(v2.is_string());
+        BOOST_TEST(v3.is_string());
+        BOOST_TEST(v4.is_string());
+        BOOST_TEST(v5.is_string());
+        BOOST_TEST(toml::get<std::string>(v1) == "foo");
+        BOOST_TEST(toml::get<std::string>(v2) == "foo");
+        BOOST_TEST(toml::get<std::string>(v3) == "foo");
+        BOOST_TEST(toml::get<std::string>(v4) == "foo");
+        BOOST_TEST(toml::get<std::string>(v5) == "\xE3\x81\xB2\xE3\x82\x89\xE3\x81\x8C\xE3\x81\xAA");
+    }
+    {
+        {
+            const toml::value v1 = u8R"([1,2,3])"_toml;
+            BOOST_TEST(v1.is_array());
+            const bool result = (toml::get<std::vector<int>>(v1) == std::vector<int>{1,2,3});
+            BOOST_TEST(result);
+        }
+        {
+            const toml::value v2 = u8R"([1,])"_toml;
+            BOOST_TEST(v2.is_array());
+            const bool result = (toml::get<std::vector<int>>(v2) == std::vector<int>{1});
+            BOOST_TEST(result);
+        }
+        {
+            const toml::value v3 = u8R"([[1,]])"_toml;
+            BOOST_TEST(v3.is_array());
+            const bool result = (toml::get<std::vector<int>>(toml::get<toml::array>(v3).front()) == std::vector<int>{1});
+            BOOST_TEST(result);
+        }
+        {
+            const toml::value v4 = u8R"([[1],])"_toml;
+            BOOST_TEST(v4.is_array());
+            const bool result = (toml::get<std::vector<int>>(toml::get<toml::array>(v4).front()) == std::vector<int>{1});
+            BOOST_TEST(result);
+        }
+    }
+    {
+        const toml::value v1 = u8R"({a = 42})"_toml;
+
+        BOOST_TEST(v1.is_table());
+        const bool result = toml::get<std::map<std::string,int>>(v1) ==
+                               std::map<std::string,int>{{"a", 42}};
+        BOOST_TEST(result);
+    }
+    {
+        const toml::value v1 = u8"1979-05-27"_toml;
+
+        BOOST_TEST(v1.is_local_date());
+        BOOST_TEST(toml::get<toml::local_date>(v1) ==
+                   toml::local_date(1979, toml::month_t::May, 27));
+    }
+    {
+        const toml::value v1 = u8"12:00:00"_toml;
+
+        BOOST_TEST(v1.is_local_time());
+        const bool result = toml::get<std::chrono::hours>(v1) == std::chrono::hours(12);
+        BOOST_TEST(result);
+    }
+    {
+        const toml::value v1 = u8"1979-05-27T07:32:00"_toml;
+        BOOST_TEST(v1.is_local_datetime());
+        BOOST_TEST(toml::get<toml::local_datetime>(v1) ==
+            toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27),
+                                 toml::local_time(7, 32, 0)));
+    }
+    {
+        const toml::value v1 = u8"1979-05-27T07:32:00Z"_toml;
+        BOOST_TEST(v1.is_offset_datetime());
+        BOOST_TEST(toml::get<toml::offset_datetime>(v1) ==
+            toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
+                                  toml::local_time(7, 32, 0), toml::time_offset(0, 0)));
+    }
+}

tests/test_multiple_translation_unit_1.cpp

@@ -0,0 +1,11 @@
+#include <toml.hpp>
+
+int read_a(const toml::table&);
+
+int main()
+{
+    const std::string content("a = 0");
+    std::istringstream iss(content);
+    const auto data = toml::parse(iss, "test_multiple_translation_unit.toml");
+    return read_a(toml::get<toml::table>(data));
+}

tests/test_multiple_translation_unit_2.cpp

@@ -0,0 +1,6 @@
+#include <toml.hpp>
+
+int read_a(const toml::table& t)
+{
+    return toml::get<int>(t.at("a"));
+}

tests/test_parse_array.cpp

@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_array_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
@@ -13,118 +8,281 @@ using namespace detail;
 
 BOOST_AUTO_TEST_CASE(test_oneline_array)
 {
-    TOML11_TEST_PARSE_EQUAL(parse_array, "[]", array());
+    TOML11_TEST_PARSE_EQUAL_VAT(parse_array<toml::value>, "[]", array());
     {
         array a(5);
         a[0] = toml::value(3); a[1] = toml::value(1); a[2] = toml::value(4);
         a[3] = toml::value(1); a[4] = toml::value(5);
-        TOML11_TEST_PARSE_EQUAL(parse_array, "[3,1,4,1,5]", a);
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<toml::value>, "[3,1,4,1,5]", a);
     }
     {
         array a(3);
         a[0] = toml::value("foo"); a[1] = toml::value("bar");
         a[2] = toml::value("baz");
-        TOML11_TEST_PARSE_EQUAL(parse_array, "[\"foo\", \"bar\",  \"baz\"]", a);
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<toml::value>, "[\"foo\", \"bar\",  \"baz\"]", a);
     }
     {
         array a(5);
         a[0] = toml::value(3); a[1] = toml::value(1); a[2] = toml::value(4);
         a[3] = toml::value(1); a[4] = toml::value(5);
-        TOML11_TEST_PARSE_EQUAL(parse_array, "[3,1,4,1,5,]", a);
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<toml::value>, "[3,1,4,1,5,]", a);
     }
     {
         array a(3);
         a[0] = toml::value("foo"); a[1] = toml::value("bar");
         a[2] = toml::value("baz");
-        TOML11_TEST_PARSE_EQUAL(parse_array, "[\"foo\", \"bar\",  \"baz\",]", a);
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<toml::value>, "[\"foo\", \"bar\",  \"baz\",]", a);
     }
 }
 
 BOOST_AUTO_TEST_CASE(test_oneline_array_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "[]", toml::value(array()));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[]", toml::value(array()));
     {
         array a(5);
         a[0] = toml::value(3); a[1] = toml::value(1); a[2] = toml::value(4);
         a[3] = toml::value(1); a[4] = toml::value(5);
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "[3,1,4,1,5]", toml::value(a));
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[3,1,4,1,5]", toml::value(a));
     }
     {
         array a(3);
         a[0] = toml::value("foo"); a[1] = toml::value("bar");
         a[2] = toml::value("baz");
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "[\"foo\", \"bar\",  \"baz\"]", toml::value(a));
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\", \"bar\",  \"baz\"]", toml::value(a));
     }
     {
         array a(5);
         a[0] = toml::value(3); a[1] = toml::value(1); a[2] = toml::value(4);
         a[3] = toml::value(1); a[4] = toml::value(5);
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "[3,1,4,1,5,]", toml::value(a));
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[3,1,4,1,5,]", toml::value(a));
     }
     {
         array a(3);
         a[0] = toml::value("foo"); a[1] = toml::value("bar");
         a[2] = toml::value("baz");
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "[\"foo\", \"bar\",  \"baz\",]", toml::value(a));
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\", \"bar\",  \"baz\",]", toml::value(a));
     }
 }
 
 BOOST_AUTO_TEST_CASE(test_multiline_array)
 {
-    TOML11_TEST_PARSE_EQUAL(parse_array, "[\n#comment\n]", array());
+    TOML11_TEST_PARSE_EQUAL_VAT(parse_array<basic_value< discard_comments>>, "[\n#comment\n]", typename basic_value< discard_comments>::array_type());
+    TOML11_TEST_PARSE_EQUAL_VAT(parse_array<basic_value<preserve_comments>>, "[\n#comment\n]", typename basic_value<preserve_comments>::array_type());
+
     {
-        array a(5);
-        a[0] = toml::value(3); a[1] = toml::value(1); a[2] = toml::value(4);
-        a[3] = toml::value(1); a[4] = toml::value(5);
-        TOML11_TEST_PARSE_EQUAL(parse_array, "[3,\n1,\n4,\n1,\n5]", a);
+        typename basic_value<discard_comments>::array_type a(5);
+        a[0] = basic_value<discard_comments>(3);
+        a[1] = basic_value<discard_comments>(1);
+        a[2] = basic_value<discard_comments>(4);
+        a[3] = basic_value<discard_comments>(1);
+        a[4] = basic_value<discard_comments>(5);
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<basic_value<discard_comments>>, "[3,\n1,\n4,\n1,\n5]", a);
     }
     {
-        array a(3);
-        a[0] = toml::value("foo"); a[1] = toml::value("bar");
-        a[2] = toml::value("baz");
-        TOML11_TEST_PARSE_EQUAL(parse_array, "[\"foo\",\n\"bar\",\n\"baz\"]", a);
+        typename basic_value<preserve_comments>::array_type a(5);
+        a[0] = basic_value<preserve_comments>(3);
+        a[1] = basic_value<preserve_comments>(1);
+        a[2] = basic_value<preserve_comments>(4);
+        a[3] = basic_value<preserve_comments>(1);
+        a[4] = basic_value<preserve_comments>(5);
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<basic_value<preserve_comments>>, "[3,\n1,\n4,\n1,\n5]", a);
     }
 
     {
-        array a(5);
-        a[0] = toml::value(3); a[1] = toml::value(1); a[2] = toml::value(4);
-        a[3] = toml::value(1); a[4] = toml::value(5);
-        TOML11_TEST_PARSE_EQUAL(parse_array, "[3,#comment\n1,#comment\n4,#comment\n1,#comment\n5]", a);
+        typename basic_value<discard_comments>::array_type a(5);
+        a[0] = basic_value<discard_comments>(3);
+        a[1] = basic_value<discard_comments>(1);
+        a[2] = basic_value<discard_comments>(4);
+        a[3] = basic_value<discard_comments>(1);
+        a[4] = basic_value<discard_comments>(5);
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<basic_value<discard_comments>>, "[3,#comment\n1,#comment\n4,#comment\n1,#comment\n5 #comment\n]", a);
     }
     {
-        array a(3);
-        a[0] = toml::value("foo"); a[1] = toml::value("b#r");
-        a[2] = toml::value("b#z");
-        TOML11_TEST_PARSE_EQUAL(parse_array, "[\"foo\",#comment\n\"b#r\",#comment\n\"b#z\"#comment\n]", a);
+        typename basic_value<preserve_comments>::array_type a(5);
+        a[0] = basic_value<preserve_comments>(3, {"comment"});
+        a[1] = basic_value<preserve_comments>(1, {"comment"});
+        a[2] = basic_value<preserve_comments>(4, {"comment"});
+        a[3] = basic_value<preserve_comments>(1, {"comment"});
+        a[4] = basic_value<preserve_comments>(5, {"comment"});
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<basic_value<preserve_comments>>, "[3,#comment\n1,#comment\n4,#comment\n1,#comment\n5 #comment\n]", a);
+    }
+
+
+    {
+        typename basic_value<discard_comments>::array_type a(3);
+        a[0] = basic_value<discard_comments>("foo");
+        a[1] = basic_value<discard_comments>("bar");
+        a[2] = basic_value<discard_comments>("baz");
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<basic_value<discard_comments>>, "[\"foo\",\n\"bar\",\n\"baz\"]", a);
+    }
+    {
+        typename basic_value<preserve_comments>::array_type a(3);
+        a[0] = basic_value<preserve_comments>("foo");
+        a[1] = basic_value<preserve_comments>("bar");
+        a[2] = basic_value<preserve_comments>("baz");
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<basic_value<preserve_comments>>, "[\"foo\",\n\"bar\",\n\"baz\"]", a);
+    }
+
+    {
+        typename basic_value<discard_comments>::array_type a(3);
+        a[0] = basic_value<discard_comments>("foo");
+        a[1] = basic_value<discard_comments>("b#r");
+        a[2] = basic_value<discard_comments>("b#z");
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<basic_value<discard_comments>>, "[\"foo\",#comment\n\"b#r\",#comment\n\"b#z\"#comment\n]", a);
+    }
+    {
+        typename basic_value<preserve_comments>::array_type a(3);
+        a[0] = basic_value<preserve_comments>("foo", {"comment"});
+        a[1] = basic_value<preserve_comments>("b#r", {"comment"});
+        a[2] = basic_value<preserve_comments>("b#z", {"comment"});
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_array<basic_value<preserve_comments>>, "[\"foo\",#comment\n\"b#r\",#comment\n\"b#z\"#comment\n]", a);
     }
 }
 
 BOOST_AUTO_TEST_CASE(test_multiline_array_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "[\n#comment\n]", toml::value(array()));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value< discard_comments>>, "[\n#comment\n]", basic_value< discard_comments>(typename basic_value< discard_comments>::array_type()));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<preserve_comments>>, "[\n#comment\n]", basic_value<preserve_comments>(typename basic_value<preserve_comments>::array_type()));
+
     {
-        array a(5);
-        a[0] = toml::value(3); a[1] = toml::value(1); a[2] = toml::value(4);
-        a[3] = toml::value(1); a[4] = toml::value(5);
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "[3,\n1,\n4,\n1,\n5]", toml::value(a));
+        typename basic_value<discard_comments>::array_type a(5);
+        a[0] = basic_value<discard_comments>(3);
+        a[1] = basic_value<discard_comments>(1);
+        a[2] = basic_value<discard_comments>(4);
+        a[3] = basic_value<discard_comments>(1);
+        a[4] = basic_value<discard_comments>(5);
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<discard_comments>>, "[3,\n1,\n4,\n1,\n5]", basic_value<discard_comments>(a));
     }
     {
-        array a(3);
-        a[0] = toml::value("foo"); a[1] = toml::value("bar");
-        a[2] = toml::value("baz");
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "[\"foo\",\n\"bar\",\n\"baz\"]", toml::value(a));
+        typename basic_value<preserve_comments>::array_type a(5);
+        a[0] = basic_value<preserve_comments>(3);
+        a[1] = basic_value<preserve_comments>(1);
+        a[2] = basic_value<preserve_comments>(4);
+        a[3] = basic_value<preserve_comments>(1);
+        a[4] = basic_value<preserve_comments>(5);
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<preserve_comments>>, "[3,\n1,\n4,\n1,\n5]", basic_value<preserve_comments>(a));
     }
 
     {
-        array a(5);
-        a[0] = toml::value(3); a[1] = toml::value(1); a[2] = toml::value(4);
-        a[3] = toml::value(1); a[4] = toml::value(5);
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "[3,#comment\n1,#comment\n4,#comment\n1,#comment\n5]", toml::value(a));
+        typename basic_value<discard_comments>::array_type a(5);
+        a[0] = basic_value<discard_comments>(3);
+        a[1] = basic_value<discard_comments>(1);
+        a[2] = basic_value<discard_comments>(4);
+        a[3] = basic_value<discard_comments>(1);
+        a[4] = basic_value<discard_comments>(5);
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<discard_comments>>, "[3,#comment\n1,#comment\n4,#comment\n1,#comment\n5 #comment\n]", basic_value<discard_comments>(a));
     }
     {
-        array a(3);
-        a[0] = toml::value("foo"); a[1] = toml::value("b#r");
-        a[2] = toml::value("b#z");
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "[\"foo\",#comment\n\"b#r\",#comment\n\"b#z\"#comment\n]", toml::value(a));
+        typename basic_value<preserve_comments>::array_type a(5);
+        a[0] = basic_value<preserve_comments>(3, {"comment"});
+        a[1] = basic_value<preserve_comments>(1, {"comment"});
+        a[2] = basic_value<preserve_comments>(4, {"comment"});
+        a[3] = basic_value<preserve_comments>(1, {"comment"});
+        a[4] = basic_value<preserve_comments>(5, {"comment"});
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<preserve_comments>>, "[3,#comment\n1,#comment\n4,#comment\n1,#comment\n5 #comment\n]", basic_value<preserve_comments>(a));
     }
+
+
+    {
+        typename basic_value<discard_comments>::array_type a(3);
+        a[0] = basic_value<discard_comments>("foo");
+        a[1] = basic_value<discard_comments>("bar");
+        a[2] = basic_value<discard_comments>("baz");
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<discard_comments>>, "[\"foo\",\n\"bar\",\n\"baz\"]", basic_value<discard_comments>(a));
+    }
+    {
+        typename basic_value<preserve_comments>::array_type a(3);
+        a[0] = basic_value<preserve_comments>("foo");
+        a[1] = basic_value<preserve_comments>("bar");
+        a[2] = basic_value<preserve_comments>("baz");
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<preserve_comments>>, "[\"foo\",\n\"bar\",\n\"baz\"]", basic_value<preserve_comments>(a));
+    }
+
+    {
+        typename basic_value<discard_comments>::array_type a(3);
+        a[0] = basic_value<discard_comments>("foo");
+        a[1] = basic_value<discard_comments>("b#r");
+        a[2] = basic_value<discard_comments>("b#z");
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<discard_comments>>, "[\"foo\",#comment\n\"b#r\",#comment\n\"b#z\"#comment\n]", basic_value<discard_comments>(a));
+    }
+    {
+        typename basic_value<preserve_comments>::array_type a(3);
+        a[0] = basic_value<preserve_comments>("foo", {"comment"});
+        a[1] = basic_value<preserve_comments>("b#r", {"comment"});
+        a[2] = basic_value<preserve_comments>("b#z", {"comment"});
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<preserve_comments>>, "[\"foo\",#comment\n\"b#r\",#comment\n\"b#z\"#comment\n]", basic_value<preserve_comments>(a));
+    }
+
+}
+
+BOOST_AUTO_TEST_CASE(test_heterogeneous_array)
+{
+#ifndef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("In strict TOML v0.5.0, heterogeneous arrays are not allowed.");
+#else
+    {
+        array a(5);
+        a[0] = toml::value("foo");
+        a[1] = toml::value(3.14);
+        a[2] = toml::value(42);
+        a[3] = toml::value{toml::value("array"), toml::value("of"), toml::value("hetero-array"), toml::value(1)};
+        a[4] = toml::value{{"key", "value"}};
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\", 3.14, 42, [\"array\", \"of\", \"hetero-array\", 1], {key = \"value\"}]", toml::value(a));
+    }
+    {
+        array a(5);
+        a[0] = toml::value("foo");
+        a[1] = toml::value(3.14);
+        a[2] = toml::value(42);
+        a[3] = toml::value{toml::value("array"), toml::value("of"), toml::value("hetero-array"), toml::value(1)};
+        a[4] = toml::value{{"key", "value"}};
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\",\n 3.14,\n 42,\n [\"array\", \"of\", \"hetero-array\", 1],\n {key = \"value\"},\n]", toml::value(a));
+    }
+    {
+        array a(5);
+        a[0] = toml::value("foo");
+        a[1] = toml::value(3.14);
+        a[2] = toml::value(42);
+        a[3] = toml::value{toml::value("array"), toml::value("of"), toml::value("hetero-array"), toml::value(1)};
+        a[4] = toml::value{{"key", "value"}};
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\",#comment\n 3.14,#comment\n 42,#comment\n [\"array\", \"of\", \"hetero-array\", 1],#comment\n {key = \"value\"},#comment\n]#comment", toml::value(a));
+    }
+    {
+        array a(5);
+        a[0] = toml::value("foo");
+        a[1] = toml::value(3.14);
+        a[2] = toml::value(42);
+        a[3] = toml::value{toml::value("array"), toml::value("of"), toml::value("hetero-array"), toml::value(1)};
+        a[4] = toml::value{{"key", "value"}};
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\",\n 3.14,\n 42,\n [\"array\",\n \"of\",\n \"hetero-array\",\n 1],\n {key = \"value\"},\n]", toml::value(a));
+    }
+#endif
+}
+
+BOOST_AUTO_TEST_CASE(test_comments_after_comma)
+{
+    {
+        typename basic_value<discard_comments>::array_type a(3);
+        a[0] = basic_value<discard_comments>("foo");
+        a[1] = basic_value<discard_comments>("bar");
+        a[2] = basic_value<discard_comments>("baz");
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<discard_comments>>,
+            "[ \"foo\" # comment\n"
+            ", \"bar\" # comment\n"
+            ", \"baz\" # comment\n"
+            "]", basic_value<discard_comments>(a));
+    }
+
+    {
+        typename basic_value<preserve_comments>::array_type a(3);
+        a[0] = basic_value<preserve_comments>("foo", {" comment"});
+        a[1] = basic_value<preserve_comments>("bar", {" comment"});
+        a[2] = basic_value<preserve_comments>("baz", {" comment"});
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<basic_value<preserve_comments>>,
+            "[ \"foo\" # comment\n"
+            ", \"bar\" # comment\n"
+            ", \"baz\" # comment\n"
+            "]", basic_value<preserve_comments>(a));
+    }
+
 }

tests/test_parse_aux.hpp

@@ -1,22 +1,37 @@
 #include <iostream>
 #include <iomanip>
 #include <algorithm>
-#include <toml/region.hpp>
-#include <toml/result.hpp>
+#include <toml.hpp>
 
 // some of the parsers returns not only a value but also a region.
 #define TOML11_TEST_PARSE_EQUAL(psr, tkn, expct)                               \
 do {                                                                           \
     const std::string token(tkn);                                              \
-    toml::detail::location<std::string> loc("test", token);                    \
+    toml::detail::location loc("test", token);                                 \
     const auto result = psr(loc);                                              \
-    BOOST_CHECK(result.is_ok());                                               \
+    BOOST_TEST(result.is_ok());                                                \
     if(result.is_ok()){                                                        \
-    BOOST_CHECK(result.unwrap().first == expct);                               \
+        BOOST_TEST(result.unwrap().first == expct);                            \
     } else {                                                                   \
-    std::cerr << "parser " << #psr << " failed with input `";                  \
-    std::cerr << token << "`.\n";                                              \
-    std::cerr << "reason: " << result.unwrap_err() << '\n';                    \
+        std::cerr << "parser " << #psr << " failed with input `";              \
+        std::cerr << token << "`.\n";                                          \
+        std::cerr << "reason: " << result.unwrap_err() << '\n';                \
+    }                                                                          \
+} while(false);                                                                \
+/**/
+
+#define TOML11_TEST_PARSE_EQUAL_VAT(psr, tkn, expct)                           \
+do {                                                                           \
+    const std::string token(tkn);                                              \
+    toml::detail::location loc("test", token);                                 \
+    const auto result = psr(loc, 0);                                           \
+    BOOST_TEST(result.is_ok());                                                \
+    if(result.is_ok()){                                                        \
+        BOOST_TEST(result.unwrap().first == expct);                            \
+    } else {                                                                   \
+        std::cerr << "parser " << #psr << " failed with input `";              \
+        std::cerr << token << "`.\n";                                          \
+        std::cerr << "reason: " << result.unwrap_err() << '\n';                \
     }                                                                          \
 } while(false);                                                                \
 /**/
@@ -24,15 +39,16 @@ do {                                                                           \
 #define TOML11_TEST_PARSE_EQUAL_VALUE(psr, tkn, expct)                         \
 do {                                                                           \
     const std::string token(tkn);                                              \
-    toml::detail::location<std::string> loc("test", token);                    \
-    const auto result = psr(loc);                                              \
-    BOOST_CHECK(result.is_ok());                                               \
+    toml::detail::location loc("test", token);                                 \
+    const auto result = psr(loc, 0);                                           \
+    BOOST_TEST(result.is_ok());                                                \
     if(result.is_ok()){                                                        \
-    BOOST_CHECK(result.unwrap() == expct);                                     \
+        BOOST_TEST(result.unwrap() == expct);                                  \
     } else {                                                                   \
-    std::cerr << "parse_value failed with input `";                            \
-    std::cerr << token << "`.\n";                                              \
-    std::cerr << "reason: " << result.unwrap_err() << '\n';                    \
+        std::cerr << "parse_value failed with input `";                        \
+        std::cerr << token << "`.\n";                                          \
+        std::cerr << "reason: " << result.unwrap_err() << '\n';                \
     }                                                                          \
 } while(false);                                                                \
 /**/
+

tests/test_parse_boolean.cpp

@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "test_parse_boolean"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
@@ -19,6 +14,6 @@ BOOST_AUTO_TEST_CASE(test_boolean)
 
 BOOST_AUTO_TEST_CASE(test_boolean_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value,  "true", toml::value( true));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "false", toml::value(false));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,  "true", toml::value( true));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "false", toml::value(false));
 }

tests/test_parse_datetime.cpp

@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_datetime_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
@@ -17,25 +12,138 @@ BOOST_AUTO_TEST_CASE(test_time)
     TOML11_TEST_PARSE_EQUAL(parse_local_time, "07:32:00.99",     toml::local_time(7, 32, 0, 990, 0));
     TOML11_TEST_PARSE_EQUAL(parse_local_time, "07:32:00.999",    toml::local_time(7, 32, 0, 999, 0));
     TOML11_TEST_PARSE_EQUAL(parse_local_time, "07:32:00.999999", toml::local_time(7, 32, 0, 999, 999));
+
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_time, "00:00:00.000000", toml::local_time( 0,  0,  0,   0,   0));
+    TOML11_TEST_PARSE_EQUAL(parse_local_time, "23:59:59.999999", toml::local_time(23, 59, 59, 999, 999));
+    TOML11_TEST_PARSE_EQUAL(parse_local_time, "23:59:60.999999", toml::local_time(23, 59, 60, 999, 999)); // leap second
 }
 
 BOOST_AUTO_TEST_CASE(test_time_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "07:32:00",        toml::value(toml::local_time(7, 32, 0)));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "07:32:00.99",     toml::value(toml::local_time(7, 32, 0, 990, 0)));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "07:32:00.999",    toml::value(toml::local_time(7, 32, 0, 999, 0)));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "07:32:00.999999", toml::value(toml::local_time(7, 32, 0, 999, 999)));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "07:32:00",        toml::value(toml::local_time(7, 32, 0)));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "07:32:00.99",     toml::value(toml::local_time(7, 32, 0, 990, 0)));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "07:32:00.999",    toml::value(toml::local_time(7, 32, 0, 999, 0)));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "07:32:00.999999", toml::value(toml::local_time(7, 32, 0, 999, 999)));
+
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "00:00:00.000000", toml::value(toml::local_time( 0,  0,  0,   0,   0)));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "23:59:59.999999", toml::value(toml::local_time(23, 59, 59, 999, 999)));
+
+    std::istringstream stream1(std::string("invalid-datetime = 24:00:00"));
+    std::istringstream stream2(std::string("invalid-datetime = 00:60:00"));
+    std::istringstream stream3(std::string("invalid-datetime = 00:00:61"));
+    BOOST_CHECK_THROW(toml::parse(stream1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream2), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream3), toml::syntax_error);
 }
 
 BOOST_AUTO_TEST_CASE(test_date)
 {
-    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "1979-05-27",
-                            toml::local_date(1979, toml::month_t::May, 27));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "1979-05-27", toml::local_date(1979, toml::month_t::May, 27));
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-01-01", toml::local_date(2000, toml::month_t::Jan,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-01-31", toml::local_date(2000, toml::month_t::Jan, 31));
+    std::istringstream stream1_1(std::string("invalid-datetime = 2000-01-00"));
+    std::istringstream stream1_2(std::string("invalid-datetime = 2000-01-32"));
+    BOOST_CHECK_THROW(toml::parse(stream1_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream1_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-02-01", toml::local_date(2000, toml::month_t::Feb,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-02-29", toml::local_date(2000, toml::month_t::Feb, 29));
+    std::istringstream stream2_1(std::string("invalid-datetime = 2000-02-00"));
+    std::istringstream stream2_2(std::string("invalid-datetime = 2000-02-30"));
+    BOOST_CHECK_THROW(toml::parse(stream2_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream2_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2001-02-28", toml::local_date(2001, toml::month_t::Feb, 28));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2004-02-29", toml::local_date(2004, toml::month_t::Feb, 29));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2100-02-28", toml::local_date(2100, toml::month_t::Feb, 28));
+    std::istringstream stream2_3(std::string("invalid-datetime = 2001-02-29"));
+    std::istringstream stream2_4(std::string("invalid-datetime = 2004-02-30"));
+    std::istringstream stream2_5(std::string("invalid-datetime = 2100-02-29"));
+    BOOST_CHECK_THROW(toml::parse(stream2_3), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream2_4), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream2_5), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-03-01", toml::local_date(2000, toml::month_t::Mar,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-03-31", toml::local_date(2000, toml::month_t::Mar, 31));
+    std::istringstream stream3_1(std::string("invalid-datetime = 2000-03-00"));
+    std::istringstream stream3_2(std::string("invalid-datetime = 2000-03-32"));
+    BOOST_CHECK_THROW(toml::parse(stream3_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream3_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-04-01", toml::local_date(2000, toml::month_t::Apr,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-04-30", toml::local_date(2000, toml::month_t::Apr, 30));
+    std::istringstream stream4_1(std::string("invalid-datetime = 2000-04-00"));
+    std::istringstream stream4_2(std::string("invalid-datetime = 2000-04-31"));
+    BOOST_CHECK_THROW(toml::parse(stream4_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream4_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-05-01", toml::local_date(2000, toml::month_t::May,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-05-31", toml::local_date(2000, toml::month_t::May, 31));
+    std::istringstream stream5_1(std::string("invalid-datetime = 2000-05-00"));
+    std::istringstream stream5_2(std::string("invalid-datetime = 2000-05-32"));
+    BOOST_CHECK_THROW(toml::parse(stream5_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream5_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-06-01", toml::local_date(2000, toml::month_t::Jun,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-06-30", toml::local_date(2000, toml::month_t::Jun, 30));
+    std::istringstream stream6_1(std::string("invalid-datetime = 2000-06-00"));
+    std::istringstream stream6_2(std::string("invalid-datetime = 2000-06-31"));
+    BOOST_CHECK_THROW(toml::parse(stream6_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream6_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-07-01", toml::local_date(2000, toml::month_t::Jul,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-07-31", toml::local_date(2000, toml::month_t::Jul, 31));
+    std::istringstream stream7_1(std::string("invalid-datetime = 2000-07-00"));
+    std::istringstream stream7_2(std::string("invalid-datetime = 2000-07-32"));
+    BOOST_CHECK_THROW(toml::parse(stream7_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream7_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-08-01", toml::local_date(2000, toml::month_t::Aug,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-08-31", toml::local_date(2000, toml::month_t::Aug, 31));
+    std::istringstream stream8_1(std::string("invalid-datetime = 2000-08-00"));
+    std::istringstream stream8_2(std::string("invalid-datetime = 2000-08-32"));
+    BOOST_CHECK_THROW(toml::parse(stream8_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream8_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-09-01", toml::local_date(2000, toml::month_t::Sep,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-09-30", toml::local_date(2000, toml::month_t::Sep, 30));
+    std::istringstream stream9_1(std::string("invalid-datetime = 2000-09-00"));
+    std::istringstream stream9_2(std::string("invalid-datetime = 2000-09-31"));
+    BOOST_CHECK_THROW(toml::parse(stream9_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream9_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-10-01", toml::local_date(2000, toml::month_t::Oct,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-10-31", toml::local_date(2000, toml::month_t::Oct, 31));
+    std::istringstream stream10_1(std::string("invalid-datetime = 2000-10-00"));
+    std::istringstream stream10_2(std::string("invalid-datetime = 2000-10-32"));
+    BOOST_CHECK_THROW(toml::parse(stream10_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream10_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-11-01", toml::local_date(2000, toml::month_t::Nov,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-11-30", toml::local_date(2000, toml::month_t::Nov, 30));
+    std::istringstream stream11_1(std::string("invalid-datetime = 2000-11-00"));
+    std::istringstream stream11_2(std::string("invalid-datetime = 2000-11-31"));
+    BOOST_CHECK_THROW(toml::parse(stream11_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream11_2), toml::syntax_error);
+
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-12-01", toml::local_date(2000, toml::month_t::Dec,  1));
+    TOML11_TEST_PARSE_EQUAL(parse_local_date,  "2000-12-31", toml::local_date(2000, toml::month_t::Dec, 31));
+    std::istringstream stream12_1(std::string("invalid-datetime = 2000-12-00"));
+    std::istringstream stream12_2(std::string("invalid-datetime = 2000-12-32"));
+    BOOST_CHECK_THROW(toml::parse(stream12_1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream12_2), toml::syntax_error);
+
+    std::istringstream stream13_1(std::string("invalid-datetime = 2000-13-01"));
+    BOOST_CHECK_THROW(toml::parse(stream13_1), toml::syntax_error);
+    std::istringstream stream0_1(std::string("invalid-datetime = 2000-00-01"));
+    BOOST_CHECK_THROW(toml::parse(stream0_1), toml::syntax_error);
 }
+
 BOOST_AUTO_TEST_CASE(test_date_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27",
-                            value(toml::local_date(1979, toml::month_t::May, 27)));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27", value(toml::local_date(1979, toml::month_t::May, 27)));
 }
 
 BOOST_AUTO_TEST_CASE(test_datetime)
@@ -64,25 +172,25 @@ BOOST_AUTO_TEST_CASE(test_datetime)
 
 BOOST_AUTO_TEST_CASE(test_datetime_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27T07:32:00",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27T07:32:00",
         toml::value(toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27), toml::local_time(7, 32, 0))));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27T07:32:00.99",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27T07:32:00.99",
         toml::value(toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27), toml::local_time(7, 32, 0, 990, 0))));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27T07:32:00.999999",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27T07:32:00.999999",
         toml::value(toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27), toml::local_time(7, 32, 0, 999, 999))));
 
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27t07:32:00",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27t07:32:00",
         toml::value(toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27), toml::local_time(7, 32, 0))));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27t07:32:00.99",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27t07:32:00.99",
         toml::value(toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27), toml::local_time(7, 32, 0, 990, 0))));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27t07:32:00.999999",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27t07:32:00.999999",
         toml::value(toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27), toml::local_time(7, 32, 0, 999, 999))));
 
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27 07:32:00",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27 07:32:00",
         toml::value(toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27), toml::local_time(7, 32, 0))));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27 07:32:00.99",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27 07:32:00.99",
         toml::value(toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27), toml::local_time(7, 32, 0, 990, 0))));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27 07:32:00.999999",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27 07:32:00.999999",
         toml::value(toml::local_datetime(toml::local_date(1979, toml::month_t::May, 27), toml::local_time(7, 32, 0, 999, 999))));
 }
 
@@ -107,27 +215,32 @@ BOOST_AUTO_TEST_CASE(test_offset_datetime)
     TOML11_TEST_PARSE_EQUAL(parse_offset_datetime, "1979-05-27T07:32:00.999999+09:00",
         toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
                               toml::local_time(7, 32, 0, 999, 999), toml::time_offset(9, 0)));
+
+    std::istringstream stream1(std::string("invalid-datetime = 2000-01-01T00:00:00+24:00"));
+    std::istringstream stream2(std::string("invalid-datetime = 2000-01-01T00:00:00+00:60"));
+    BOOST_CHECK_THROW(toml::parse(stream1), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(stream2), toml::syntax_error);
 }
 
 BOOST_AUTO_TEST_CASE(test_offset_datetime_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27T07:32:00Z",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27T07:32:00Z",
         toml::value(toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
                               toml::local_time(7, 32, 0), toml::time_offset(0, 0))));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27T07:32:00.99Z",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27T07:32:00.99Z",
         toml::value(toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
                               toml::local_time(7, 32, 0, 990, 0), toml::time_offset(0, 0))));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27T07:32:00.999999Z",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27T07:32:00.999999Z",
         toml::value(toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
                               toml::local_time(7, 32, 0, 999, 999), toml::time_offset(0, 0))));
 
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27T07:32:00+09:00",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27T07:32:00+09:00",
         toml::value(toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
                               toml::local_time(7, 32, 0), toml::time_offset(9, 0))));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27T07:32:00.99+09:00",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27T07:32:00.99+09:00",
         toml::value(toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
                               toml::local_time(7, 32, 0, 990, 0), toml::time_offset(9, 0))));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27T07:32:00.999999+09:00",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27T07:32:00.999999+09:00",
         toml::value(toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
                               toml::local_time(7, 32, 0, 999, 999), toml::time_offset(9, 0))));
 }

tests/test_parse_floating.cpp

@@ -1,14 +1,10 @@
-#define BOOST_TEST_MODULE "parse_floating_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
-#include <cmath>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
+#include <cmath>
+
 using namespace toml;
 using namespace detail;
 
@@ -32,20 +28,20 @@ BOOST_AUTO_TEST_CASE(test_fractional)
 
 BOOST_AUTO_TEST_CASE(test_fractional_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1.0",               value( 1.0));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0.1",               value( 0.1));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0.001",             value( 0.001));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0.100",             value( 0.1));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "+3.14",             value( 3.14));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "-3.14",             value(-3.14));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "3.1415_9265_3589",  value( 3.141592653589));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "+3.1415_9265_3589", value( 3.141592653589));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "-3.1415_9265_3589", value(-3.141592653589));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "123_456.789",       value( 123456.789));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "+123_456.789",      value( 123456.789));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "-123_456.789",      value(-123456.789));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "+0.0",              value( 0.0));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "-0.0",              value(-0.0));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1.0",               value( 1.0));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0.1",               value( 0.1));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0.001",             value( 0.001));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0.100",             value( 0.1));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "+3.14",             value( 3.14));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "-3.14",             value(-3.14));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "3.1415_9265_3589",  value( 3.141592653589));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "+3.1415_9265_3589", value( 3.141592653589));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "-3.1415_9265_3589", value(-3.141592653589));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "123_456.789",       value( 123456.789));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "+123_456.789",      value( 123456.789));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "-123_456.789",      value(-123456.789));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "+0.0",              value( 0.0));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "-0.0",              value(-0.0));
 }
 
 BOOST_AUTO_TEST_CASE(test_exponential)
@@ -68,28 +64,42 @@ BOOST_AUTO_TEST_CASE(test_exponential)
     TOML11_TEST_PARSE_EQUAL(parse_floating, "1_2_3E-1_0", 123e-10);
     TOML11_TEST_PARSE_EQUAL(parse_floating, "+0e0",        0.0);
     TOML11_TEST_PARSE_EQUAL(parse_floating, "-0e0",       -0.0);
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_PARSE_EQUAL(parse_floating, "1_2_3E-01",  123e-1);
+    TOML11_TEST_PARSE_EQUAL(parse_floating, "1_2_3E-0_1", 123e-1);
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_exponential_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1e10",       value(1e10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1e+10",      value(1e10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1e-10",      value(1e-10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "+1e10",      value(1e10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "+1e+10",     value(1e10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "+1e-10",     value(1e-10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "-1e10",      value(-1e10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "-1e+10",     value(-1e10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "-1e-10",     value(-1e-10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "123e-10",    value(123e-10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1E10",       value(1e10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1E+10",      value(1e10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1E-10",      value(1e-10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "123E-10",    value(123e-10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1_2_3E-10",  value(123e-10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1_2_3E-1_0", value(123e-10));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "+0e0",       value( 0.0));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "-0e0",       value(-0.0));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1e10",       value(1e10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1e+10",      value(1e10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1e-10",      value(1e-10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "+1e10",      value(1e10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "+1e+10",     value(1e10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "+1e-10",     value(1e-10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "-1e10",      value(-1e10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "-1e+10",     value(-1e10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "-1e-10",     value(-1e-10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "123e-10",    value(123e-10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1E10",       value(1e10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1E+10",      value(1e10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1E-10",      value(1e-10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "123E-10",    value(123e-10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1_2_3E-10",  value(123e-10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1_2_3E-1_0", value(123e-10));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "+0e0",       value( 0.0));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "-0e0",       value(-0.0));
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1_2_3E-01",  value(123e-1));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1_2_3E-0_1", value(123e-1));
+#endif
 }
 BOOST_AUTO_TEST_CASE(test_fe)
 {
@@ -99,16 +109,22 @@ BOOST_AUTO_TEST_CASE(test_fe)
 }
 BOOST_AUTO_TEST_CASE(test_fe_vaule)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "6.02e23",          value(6.02e23));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "6.02e+23",         value(6.02e23));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1.112_650_06e-17", value(1.11265006e-17));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "6.02e23",          value(6.02e23));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "6.02e+23",         value(6.02e23));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1.112_650_06e-17", value(1.11265006e-17));
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "3.141_5e-01",      value(3.1415e-1));
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_inf)
 {
     {
         const std::string token("inf");
-        toml::detail::location<std::string> loc("test", token);
+        toml::detail::location loc("test", token);
         const auto r = parse_floating(loc);
         BOOST_CHECK(r.is_ok());
         BOOST_CHECK(std::isinf(r.unwrap().first));
@@ -116,7 +132,7 @@ BOOST_AUTO_TEST_CASE(test_inf)
     }
     {
         const std::string token("+inf");
-        toml::detail::location<std::string> loc("test", token);
+        toml::detail::location loc("test", token);
         const auto r = parse_floating(loc);
         BOOST_CHECK(r.is_ok());
         BOOST_CHECK(std::isinf(r.unwrap().first));
@@ -124,7 +140,7 @@ BOOST_AUTO_TEST_CASE(test_inf)
     }
     {
         const std::string token("-inf");
-        toml::detail::location<std::string> loc("test", token);
+        toml::detail::location loc("test", token);
         const auto r = parse_floating(loc);
         BOOST_CHECK(r.is_ok());
         BOOST_CHECK(std::isinf(r.unwrap().first));
@@ -136,23 +152,30 @@ BOOST_AUTO_TEST_CASE(test_nan)
 {
     {
         const std::string token("nan");
-        toml::detail::location<std::string> loc("test", token);
+        toml::detail::location loc("test", token);
         const auto r = parse_floating(loc);
         BOOST_CHECK(r.is_ok());
         BOOST_CHECK(std::isnan(r.unwrap().first));
     }
     {
         const std::string token("+nan");
-        toml::detail::location<std::string> loc("test", token);
+        toml::detail::location loc("test", token);
         const auto r = parse_floating(loc);
         BOOST_CHECK(r.is_ok());
         BOOST_CHECK(std::isnan(r.unwrap().first));
     }
     {
         const std::string token("-nan");
-        toml::detail::location<std::string> loc("test", token);
+        toml::detail::location loc("test", token);
         const auto r = parse_floating(loc);
         BOOST_CHECK(r.is_ok());
         BOOST_CHECK(std::isnan(r.unwrap().first));
     }
 }
+
+BOOST_AUTO_TEST_CASE(test_overflow)
+{
+    std::istringstream float_overflow (std::string("float-overflow  = 1.0e+1024"));
+    BOOST_CHECK_THROW(toml::parse(float_overflow ), toml::syntax_error);
+    // istringstream >> float does not set failbit in case of underflow.
+}

tests/test_parse_inline_table.cpp

@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_inline_table_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
@@ -13,36 +8,52 @@ using namespace detail;
 
 BOOST_AUTO_TEST_CASE(test_inline_table)
 {
-    TOML11_TEST_PARSE_EQUAL(parse_inline_table, "{}", table());
+    TOML11_TEST_PARSE_EQUAL_VAT(parse_inline_table<toml::value>, "{}", table());
     {
         table t;
         t["foo"] = toml::value(42);
         t["bar"] = toml::value("baz");
-        TOML11_TEST_PARSE_EQUAL(parse_inline_table, "{foo = 42, bar = \"baz\"}", t);
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_inline_table<toml::value>, "{foo = 42, bar = \"baz\"}", t);
     }
     {
         table t;
         table t_sub;
         t_sub["name"] = toml::value("pug");
         t["type"] = toml::value(t_sub);
-        TOML11_TEST_PARSE_EQUAL(parse_inline_table, "{type.name = \"pug\"}", t);
+        TOML11_TEST_PARSE_EQUAL_VAT(parse_inline_table<toml::value>, "{type.name = \"pug\"}", t);
     }
 }
 
 BOOST_AUTO_TEST_CASE(test_inline_table_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "{}", value(table()));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "{}", value(table()));
     {
         table t;
         t["foo"] = toml::value(42);
         t["bar"] = toml::value("baz");
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "{foo = 42, bar = \"baz\"}", value(t));
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "{foo = 42, bar = \"baz\"}", value(t));
     }
     {
         table t;
         table t_sub;
         t_sub["name"] = toml::value("pug");
         t["type"] = toml::value(t_sub);
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "{type.name = \"pug\"}", value(t));
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "{type.name = \"pug\"}", value(t));
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_inline_table_immutability)
+{
+    {
+        std::istringstream stream(std::string(
+                "a = {b = 1}\n"
+                "a.c = 2\n"));
+        BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
+    }
+    {
+        std::istringstream stream(std::string(
+                "a = {b = {c = 1}}\n"
+                "a.b.d = 2\n"));
+        BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
     }
 }

tests/test_parse_integer.cpp

@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_integer_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
@@ -25,14 +20,14 @@ BOOST_AUTO_TEST_CASE(test_decimal)
 
 BOOST_AUTO_TEST_CASE(test_decimal_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value,        "1234", toml::value(     1234));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value,       "+1234", toml::value(     1234));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value,       "-1234", toml::value(    -1234));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value,           "0", toml::value(        0));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value,     "1_2_3_4", toml::value(     1234));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value,    "+1_2_3_4", toml::value(    +1234));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value,    "-1_2_3_4", toml::value(    -1234));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "123_456_789", toml::value(123456789));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,        "1234", toml::value(     1234));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,       "+1234", toml::value(     1234));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,       "-1234", toml::value(    -1234));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,           "0", toml::value(        0));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,     "1_2_3_4", toml::value(     1234));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,    "+1_2_3_4", toml::value(    +1234));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,    "-1_2_3_4", toml::value(    -1234));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "123_456_789", toml::value(123456789));
 }
 
 BOOST_AUTO_TEST_CASE(test_hex)
@@ -50,15 +45,15 @@ BOOST_AUTO_TEST_CASE(test_hex)
 
 BOOST_AUTO_TEST_CASE(test_hex_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0xDEADBEEF",  value(0xDEADBEEF));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0xdeadbeef",  value(0xDEADBEEF));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0xDEADbeef",  value(0xDEADBEEF));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0xDEAD_BEEF", value(0xDEADBEEF));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0xdead_beef", value(0xDEADBEEF));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0xdead_BEEF", value(0xDEADBEEF));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0xFF",        value(0xFF));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0x00FF",      value(0xFF));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0x0000FF",    value(0xFF));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0xDEADBEEF",  value(0xDEADBEEF));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0xdeadbeef",  value(0xDEADBEEF));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0xDEADbeef",  value(0xDEADBEEF));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0xDEAD_BEEF", value(0xDEADBEEF));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0xdead_beef", value(0xDEADBEEF));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0xdead_BEEF", value(0xDEADBEEF));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0xFF",        value(0xFF));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0x00FF",      value(0xFF));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0x0000FF",    value(0xFF));
 }
 
 BOOST_AUTO_TEST_CASE(test_oct)
@@ -70,9 +65,9 @@ BOOST_AUTO_TEST_CASE(test_oct)
 
 BOOST_AUTO_TEST_CASE(test_oct_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0o777",   value(64*7+8*7+7));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0o7_7_7", value(64*7+8*7+7));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0o007",   value(7));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0o777",   value(64*7+8*7+7));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0o7_7_7", value(64*7+8*7+7));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0o007",   value(7));
 }
 
 BOOST_AUTO_TEST_CASE(test_bin)
@@ -85,8 +80,37 @@ BOOST_AUTO_TEST_CASE(test_bin)
 
 BOOST_AUTO_TEST_CASE(test_bin_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0b10000",    value(16));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0b010000",   value(16));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0b01_00_00", value(16));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "0b111111",   value(63));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0b10000",    value(16));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0b010000",   value(16));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0b01_00_00", value(16));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "0b111111",   value(63));
+
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "0b1000_1000_1000_1000_1000_1000_1000_1000_1000_1000_1000_1000_1000_1000_1000",
+        //      1   0   0   0
+        //      0   C   8   4
+        value(0x0888888888888888));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "0b01111111_11111111_11111111_11111111_11111111_11111111_11111111_11111111",
+        //      1   0   0   0
+        //      0   C   8   4
+        value(0x7FFFFFFFFFFFFFFF));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "0b00000000_01111111_11111111_11111111_11111111_11111111_11111111_11111111_11111111",
+        //      1   0   0   0
+        //      0   C   8   4
+        value(0x7FFFFFFFFFFFFFFF));
+}
+
+BOOST_AUTO_TEST_CASE(test_integer_overflow)
+{
+    std::istringstream dec_overflow(std::string("dec-overflow = 9223372036854775808"));
+    std::istringstream hex_overflow(std::string("hex-overflow = 0x1_00000000_00000000"));
+    std::istringstream oct_overflow(std::string("oct-overflow = 0o1_000_000_000_000_000_000_000"));
+    //                                                           64       56       48       40       32       24       16        8
+    std::istringstream bin_overflow(std::string("bin-overflow = 0b10000000_00000000_00000000_00000000_00000000_00000000_00000000_00000000"));
+    BOOST_CHECK_THROW(toml::parse(dec_overflow), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(hex_overflow), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(oct_overflow), toml::syntax_error);
+    BOOST_CHECK_THROW(toml::parse(bin_overflow), toml::syntax_error);
 }

tests/test_parse_key.cpp

@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_key_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
@@ -13,23 +8,23 @@ using namespace detail;
 
 BOOST_AUTO_TEST_CASE(test_bare_key)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "barekey",  std::vector<key>(1, "barekey"));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "bare-key", std::vector<key>(1, "bare-key"));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "bare_key", std::vector<key>(1, "bare_key"));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "1234",     std::vector<key>(1, "1234"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "barekey",  std::vector<key>(1, "barekey"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "bare-key", std::vector<key>(1, "bare-key"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "bare_key", std::vector<key>(1, "bare_key"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "1234",     std::vector<key>(1, "1234"));
 }
 
 BOOST_AUTO_TEST_CASE(test_quoted_key)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "\"127.0.0.1\"",          std::vector<key>(1, "127.0.0.1"         ));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "\"character encoding\"", std::vector<key>(1, "character encoding"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "\"127.0.0.1\"",          std::vector<key>(1, "127.0.0.1"         ));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "\"character encoding\"", std::vector<key>(1, "character encoding"));
 #if defined(_MSC_VER) || defined(__INTEL_COMPILER)
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "\"\xCA\x8E\xC7\x9D\xCA\x9E\"", std::vector<key>(1, "\xCA\x8E\xC7\x9D\xCA\x9E"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "\"\xCA\x8E\xC7\x9D\xCA\x9E\"", std::vector<key>(1, "\xCA\x8E\xC7\x9D\xCA\x9E"));
 #else
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "\"ʎǝʞ\"",                std::vector<key>(1, "ʎǝʞ"               ));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "\"ʎǝʞ\"",                std::vector<key>(1, "ʎǝʞ"               ));
 #endif
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "'key2'",                 std::vector<key>(1, "key2"              ));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "'quoted \"value\"'",     std::vector<key>(1, "quoted \"value\""  ));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "'key2'",                 std::vector<key>(1, "key2"              ));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "'quoted \"value\"'",     std::vector<key>(1, "quoted \"value\""  ));
 }
 
 BOOST_AUTO_TEST_CASE(test_dotted_key)
@@ -38,13 +33,13 @@ BOOST_AUTO_TEST_CASE(test_dotted_key)
         std::vector<key> keys(2);
         keys[0] = "physical";
         keys[1] = "color";
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "physical.color", keys);
+        TOML11_TEST_PARSE_EQUAL(parse_key, "physical.color", keys);
     }
     {
         std::vector<key> keys(2);
         keys[0] = "physical";
         keys[1] = "shape";
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "physical.shape", keys);
+        TOML11_TEST_PARSE_EQUAL(parse_key, "physical.shape", keys);
     }
     {
         std::vector<key> keys(4);
@@ -52,12 +47,12 @@ BOOST_AUTO_TEST_CASE(test_dotted_key)
         keys[1] = "y";
         keys[2] = "z";
         keys[3] = "w";
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "x.y.z.w", keys);
+        TOML11_TEST_PARSE_EQUAL(parse_key, "x.y.z.w", keys);
     }
     {
         std::vector<key> keys(2);
         keys[0] = "site";
         keys[1] = "google.com";
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "site.\"google.com\"", keys);
+        TOML11_TEST_PARSE_EQUAL(parse_key, "site.\"google.com\"", keys);
     }
 }

tests/test_parse_string.cpp

@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_string_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
@@ -29,16 +24,16 @@ BOOST_AUTO_TEST_CASE(test_string)
 
 BOOST_AUTO_TEST_CASE(test_string_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\"The quick brown fox jumps over the lazy dog\"",
         toml::value("The quick brown fox jumps over the lazy dog", string_t::basic));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\'The quick brown fox jumps over the lazy dog\'",
         toml::value("The quick brown fox jumps over the lazy dog", string_t::literal));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\"\"\"The quick brown fox \\\njumps over the lazy dog\"\"\"",
         toml::value("The quick brown fox jumps over the lazy dog", string_t::basic));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "'''The quick brown fox \njumps over the lazy dog'''",
         toml::value("The quick brown fox \njumps over the lazy dog", string_t::literal));
 }
@@ -69,31 +64,37 @@ BOOST_AUTO_TEST_CASE(test_basic_string)
     TOML11_TEST_PARSE_EQUAL(parse_string,
         "\" And when \\\"'s are in the along with # \\\"\"",
         string(" And when \"'s are in the along with # \"", string_t::basic));
+    TOML11_TEST_PARSE_EQUAL(parse_string,
+        "\"Here are fifteen apostrophes: '''''''''''''''\"",
+        string("Here are fifteen apostrophes: '''''''''''''''", string_t::basic));
 }
 
 BOOST_AUTO_TEST_CASE(test_basic_string_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\"GitHub Cofounder & CEO\\nLikes tater tots and beer.\"",
         value("GitHub Cofounder & CEO\nLikes tater tots and beer.", string_t::basic));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\"192.168.1.1\"",
         value("192.168.1.1", string_t::basic));
 #if defined(_MSC_VER) || defined(__INTEL_COMPILER)
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value,
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\"\xE4\xB8\xAD\xE5\x9B\xBD\"",
         value("\xE4\xB8\xAD\xE5\x9B\xBD", string_t::basic));
 #else
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\"中国\"",
         value("中国", string_t::basic));
 #endif
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\"You'll hate me after this - #\"",
         value("You'll hate me after this - #", string_t::basic));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\" And when \\\"'s are in the along with # \\\"\"",
         value(" And when \"'s are in the along with # \"", string_t::basic));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "\"Here are fifteen apostrophes: '''''''''''''''\"",
+        value("Here are fifteen apostrophes: '''''''''''''''", string_t::basic));
 }
 
 BOOST_AUTO_TEST_CASE(test_ml_basic_string)
@@ -104,16 +105,41 @@ BOOST_AUTO_TEST_CASE(test_ml_basic_string)
     TOML11_TEST_PARSE_EQUAL(parse_string,
         "\"\"\"\\\n  The quick brown \\\n\n  fox jumps over \\\n  the lazy dog.\\\n  \"\"\"",
         string("The quick brown fox jumps over the lazy dog.", string_t::basic));
+    TOML11_TEST_PARSE_EQUAL(parse_string,
+        "\"\"\"Here are two quotation marks: \"\". Simple enough.\"\"\"",
+        string("Here are two quotation marks: \"\". Simple enough.", string_t::basic));
+    TOML11_TEST_PARSE_EQUAL(parse_string,
+        "\"\"\"Here are three quotation marks: \"\"\\\".\"\"\"",
+        string("Here are three quotation marks: \"\"\".", string_t::basic));
+    TOML11_TEST_PARSE_EQUAL(parse_string,
+        "\"\"\"Here are fifteen quotation marks: \"\"\\\"\"\"\\\"\"\"\\\"\"\"\\\"\"\"\\\".\"\"\"",
+        string("Here are fifteen quotation marks: \"\"\"\"\"\"\"\"\"\"\"\"\"\"\".", string_t::basic));
+    TOML11_TEST_PARSE_EQUAL(parse_string,
+        "\"\"\"\"This,\" she said, \"is just a pointless statement.\"\"\"\"",
+        string("\"This,\" she said, \"is just a pointless statement.\"", string_t::basic));
 }
 
 BOOST_AUTO_TEST_CASE(test_ml_basic_string_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\"\"\"\nThe quick brown \\\n\n  fox jumps over \\\n  the lazy dog.\"\"\"",
         value("The quick brown fox jumps over the lazy dog.", string_t::basic));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "\"\"\"\\\n  The quick brown \\\n\n  fox jumps over \\\n  the lazy dog.\\\n  \"\"\"",
         value("The quick brown fox jumps over the lazy dog.", string_t::basic));
+
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "\"\"\"Here are two quotation marks: \"\". Simple enough.\"\"\"",
+        value("Here are two quotation marks: \"\". Simple enough.", string_t::basic));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "\"\"\"Here are three quotation marks: \"\"\\\".\"\"\"",
+        value("Here are three quotation marks: \"\"\".", string_t::basic));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "\"\"\"Here are fifteen quotation marks: \"\"\\\"\"\"\\\"\"\"\\\"\"\"\\\"\"\"\\\".\"\"\"",
+        value("Here are fifteen quotation marks: \"\"\"\"\"\"\"\"\"\"\"\"\"\"\".", string_t::basic));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "\"\"\"\"This,\" she said, \"is just a pointless statement.\"\"\"\"",
+        value("\"This,\" she said, \"is just a pointless statement.\"", string_t::basic));
 }
 
 BOOST_AUTO_TEST_CASE(test_literal_string)
@@ -134,16 +160,16 @@ BOOST_AUTO_TEST_CASE(test_literal_string)
 
 BOOST_AUTO_TEST_CASE(test_literal_string_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "'C:\\Users\\nodejs\\templates'",
         value("C:\\Users\\nodejs\\templates", string_t::literal));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "'\\\\ServerX\\admin$\\system32\\'",
         value("\\\\ServerX\\admin$\\system32\\", string_t::literal));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "'Tom \"Dubs\" Preston-Werner'",
         value("Tom \"Dubs\" Preston-Werner", string_t::literal));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "'<\\i\\c*\\s*>'",
         value("<\\i\\c*\\s*>", string_t::literal));
 }
@@ -156,18 +182,49 @@ BOOST_AUTO_TEST_CASE(test_ml_literal_string)
     TOML11_TEST_PARSE_EQUAL(parse_string,
         "'''\nThe first newline is\ntrimmed in raw strings.\n   All other whitespace\n   is preserved.\n'''",
         string("The first newline is\ntrimmed in raw strings.\n   All other whitespace\n   is preserved.\n", string_t::literal));
+    TOML11_TEST_PARSE_EQUAL(parse_string,
+        "''''That's still pointless', she said.'''",
+        string("'That's still pointless', she said.", string_t::literal));
+    TOML11_TEST_PARSE_EQUAL(parse_string,
+        "'''Here are fifteen quotation marks: \"\"\"\"\"\"\"\"\"\"\"\"\"\"\".'''",
+        string("Here are fifteen quotation marks: \"\"\"\"\"\"\"\"\"\"\"\"\"\"\".", string_t::literal));
+    TOML11_TEST_PARSE_EQUAL(parse_string,
+        "''''This,' she said, 'is just a pointless statement.''''",
+        string("'This,' she said, 'is just a pointless statement.'", string_t::literal));
 }
 
 BOOST_AUTO_TEST_CASE(test_ml_literal_string_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "'''I [dw]on't need \\d{2} apples'''",
         value("I [dw]on't need \\d{2} apples", string_t::literal));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, 
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
         "'''\nThe first newline is\ntrimmed in raw strings.\n   All other whitespace\n   is preserved.\n'''",
         value("The first newline is\ntrimmed in raw strings.\n   All other whitespace\n   is preserved.\n", string_t::literal));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "''''That's still pointless', she said.'''",
+        value("'That's still pointless', she said.", string_t::literal));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "'''Here are fifteen quotation marks: \"\"\"\"\"\"\"\"\"\"\"\"\"\"\".'''",
+        value("Here are fifteen quotation marks: \"\"\"\"\"\"\"\"\"\"\"\"\"\"\".", string_t::literal));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>,
+        "''''This,' she said, 'is just a pointless statement.''''",
+        value("'This,' she said, 'is just a pointless statement.'", string_t::literal));
 }
 
+BOOST_AUTO_TEST_CASE(test_simple_excape_sequences)
+{
+    TOML11_TEST_PARSE_EQUAL(parse_string,
+            R"("\"\\\b\f\n\r\t")",
+            string("\"\\\b\f\n\r\t", string_t::basic));
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    TOML11_TEST_PARSE_EQUAL(parse_string,
+            R"("\e")",
+            string("\x1b", string_t::basic));
+#endif
+}
+
+
 BOOST_AUTO_TEST_CASE(test_unicode_escape_sequence)
 {
 #if defined(_MSC_VER) || defined(__INTEL_COMPILER)

tests/test_parse_table.cpp

@@ -1,12 +1,7 @@
-#define BOOST_TEST_MODULE "parse_table_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
-#include <toml/parser.hpp>
 #include <toml/get.hpp>
+#include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;
@@ -19,15 +14,15 @@ BOOST_AUTO_TEST_CASE(test_normal_table)
         "key2 = 42\n"
         "key3 = 3.14\n"
         );
-    location<std::string> loc("test", table);
+    location loc("test", table);
 
-    const auto result = toml::detail::parse_ml_table(loc);
-    BOOST_CHECK(result.is_ok());
+    const auto result = toml::detail::parse_ml_table<toml::value>(loc);
+    BOOST_TEST(result.is_ok());
     const auto data = result.unwrap();
 
-    BOOST_CHECK_EQUAL(toml::get<std::string >(data.at("key1")), "value");
-    BOOST_CHECK_EQUAL(toml::get<std::int64_t>(data.at("key2")), 42);
-    BOOST_CHECK_EQUAL(toml::get<double      >(data.at("key3")), 3.14);
+    BOOST_TEST(toml::get<std::string >(data.at("key1")) == "value");
+    BOOST_TEST(toml::get<std::int64_t>(data.at("key2")) == 42);
+    BOOST_TEST(toml::get<double      >(data.at("key3")) == 3.14);
 }
 
 BOOST_AUTO_TEST_CASE(test_nested_table)
@@ -36,15 +31,15 @@ BOOST_AUTO_TEST_CASE(test_nested_table)
         "a.b   = \"value\"\n"
         "a.c.d = 42\n"
         );
-    location<std::string> loc("test", table);
+    location loc("test", table);
 
-    const auto result = toml::detail::parse_ml_table(loc);
-    BOOST_CHECK(result.is_ok());
+    const auto result = toml::detail::parse_ml_table<toml::value>(loc);
+    BOOST_TEST(result.is_ok());
     const auto data = result.unwrap();
 
     const auto a = toml::get<toml::table>(data.at("a"));
     const auto c = toml::get<toml::table>(a.at("c"));
 
-    BOOST_CHECK_EQUAL(toml::get<std::string >(a.at("b")), "value");
-    BOOST_CHECK_EQUAL(toml::get<std::int64_t>(c.at("d")), 42);
+    BOOST_TEST(toml::get<std::string >(a.at("b")) == "value");
+    BOOST_TEST(toml::get<std::int64_t>(c.at("d")) == 42);
 }

tests/test_parse_table_key.cpp

@@ -1,11 +1,6 @@
-#define BOOST_TEST_MODULE "parse_table_key_test"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/parser.hpp>
+
+#include "unit_test.hpp"
 #include "test_parse_aux.hpp"
 
 using namespace toml;

tests/test_parse_unicode.cpp

@@ -1,24 +1,19 @@
-#define BOOST_TEST_MODULE "test_parse_unicode"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml.hpp>
-#include <iostream>
-#include <fstream>
 
-#if defined(_MSC_VER) || defined(__INTEL_COMPILER)
+#include "unit_test.hpp"
+
+#include <fstream>
+#include <iostream>
+
 BOOST_AUTO_TEST_CASE(test_hard_example_unicode)
 {
-    const auto data = toml::parse("toml/tests/hard_example_unicode.toml");
+    const auto data = toml::parse(testinput("hard_example_unicode.toml"));
 
-    const auto the = toml::get<toml::Table>(data.at("the"));
-    BOOST_CHECK_EQUAL(toml::get<std::string>(the.at("test_string")),
+    const auto the = toml::find<toml::table>(data, "the");
+    BOOST_TEST(toml::get<std::string>(the.at("test_string")) ==
                       std::string("\xC3\x9D\xC3\xB4\xC3\xBA\x27\xE2\x84\x93\xE2\x84\x93\x20\xCE\xBB\xC3\xA1\xC6\xAD\xC3\xA8\x20\xE2\x82\xA5\xC3\xA8\x20\xC3\xA1\xC6\x92\xC6\xAD\xC3\xA8\xC5\x99\x20\xC6\xAD\xCE\xBB\xC3\xAF\xC6\xA8\x20\x2D\x20\x23"));
 
-    const auto hard = toml::get<toml::Table>(the.at("hard"));
+    const auto hard = toml::get<toml::table>(the.at("hard"));
     const std::vector<std::string> expected_the_hard_test_array{"] ", " # "};
     BOOST_CHECK(toml::get<std::vector<std::string>>(hard.at("test_array")) ==
                 expected_the_hard_test_array);
@@ -28,47 +23,15 @@ BOOST_AUTO_TEST_CASE(test_hard_example_unicode)
     };
     BOOST_CHECK(toml::get<std::vector<std::string>>(hard.at("test_array2")) ==
                 expected_the_hard_test_array2);
-    BOOST_CHECK_EQUAL(toml::get<std::string>(hard.at("another_test_string")),
+    BOOST_TEST(toml::get<std::string>(hard.at("another_test_string")) ==
                       std::string("\xC2\xA7\xC3\xA1\xE2\x82\xA5\xC3\xA8\x20\xC6\xAD\xCE\xBB\xC3\xAF\xC3\xB1\xCF\xB1\x2C\x20\xCE\xB2\xC3\xBA\xC6\xAD\x20\xCF\x89\xC3\xAF\xC6\xAD\xCE\xBB\x20\xC3\xA1\x20\xC6\xA8\xC6\xAD\xC5\x99\xC3\xAF\xC3\xB1\xCF\xB1\x20\x23"));
-    BOOST_CHECK_EQUAL(toml::get<std::string>(hard.at("harder_test_string")),
+    BOOST_TEST(toml::get<std::string>(hard.at("harder_test_string")) ==
                       std::string("\x20\xC3\x82\xC3\xB1\xCE\xB4\x20\xCF\x89\xCE\xBB\xC3\xA8\xC3\xB1\x20\x22\x27\xC6\xA8\x20\xC3\xA1\xC5\x99\xC3\xA8\x20\xC3\xAF\xC3\xB1\x20\xC6\xAD\xCE\xBB\xC3\xA8\x20\xC6\xA8\xC6\xAD\xC5\x99\xC3\xAF\xC3\xB1\xCF\xB1\x2C\x20\xC3\xA1\xE2\x84\x93\xC3\xB4\xC3\xB1\xCF\xB1\x20\xCF\x89\xC3\xAF\xC6\xAD\xCE\xBB\x20\x23\x20\x22"));
 //
-    const auto bit = toml::get<toml::Table>(hard.at(std::string("\xCE\xB2\xC3\xAF\xC6\xAD\x23")));
-    BOOST_CHECK_EQUAL(toml::get<std::string>(bit.at(std::string("\xCF\x89\xCE\xBB\xC3\xA1\xC6\xAD\x3F"))),
+    const auto bit = toml::get<toml::table>(hard.at(std::string("\xCE\xB2\xC3\xAF\xC6\xAD\x23")));
+    BOOST_TEST(toml::get<std::string>(bit.at(std::string("\xCF\x89\xCE\xBB\xC3\xA1\xC6\xAD\x3F"))) ==
         std::string("\xC3\x9D\xC3\xB4\xC3\xBA\x20\xCE\xB4\xC3\xB4\xC3\xB1\x27\xC6\xAD\x20\xC6\xAD\xCE\xBB\xC3\xAF\xC3\xB1\xC6\x99\x20\xC6\xA8\xC3\xB4\xE2\x82\xA5\xC3\xA8\x20\xC3\xBA\xC6\xA8\xC3\xA8\xC5\x99\x20\xCF\x89\xC3\xB4\xC3\xB1\x27\xC6\xAD\x20\xCE\xB4\xC3\xB4\x20\xC6\xAD\xCE\xBB\xC3\xA1\xC6\xAD\x3F"));
     const std::vector<std::string> expected_multi_line_array{"]"};
     BOOST_CHECK(toml::get<std::vector<std::string>>(bit.at("multi_line_array")) ==
                 expected_multi_line_array);
 }
-#else
-BOOST_AUTO_TEST_CASE(test_hard_example_unicode)
-{
-    const auto data = toml::parse("toml/tests/hard_example_unicode.toml");
-
-    const auto the = toml::get<toml::Table>(data.at("the"));
-    BOOST_CHECK_EQUAL(toml::get<std::string>(the.at("test_string")),
-                      std::string(u8"Ýôú'ℓℓ λáƭè ₥è áƒƭèř ƭλïƨ - #"));
-
-    const auto hard = toml::get<toml::Table>(the.at("hard"));
-    const std::vector<std::string> expected_the_hard_test_array{"] ", " # "};
-    BOOST_CHECK(toml::get<std::vector<std::string>>(hard.at("test_array")) ==
-                expected_the_hard_test_array);
-    const std::vector<std::string> expected_the_hard_test_array2{
-            std::string(u8"Tèƨƭ #11 ]ƥřôƲèδ ƭλáƭ"),
-            std::string(u8"Éжƥèřï₥èñƭ #9 ωáƨ á ƨúççèƨƨ")};
-    BOOST_CHECK(toml::get<std::vector<std::string>>(hard.at("test_array2")) ==
-                expected_the_hard_test_array2);
-    BOOST_CHECK_EQUAL(toml::get<std::string>(hard.at("another_test_string")),
-                      std::string(u8"§á₥è ƭλïñϱ, βúƭ ωïƭλ á ƨƭřïñϱ #"));
-    BOOST_CHECK_EQUAL(toml::get<std::string>(hard.at("harder_test_string")),
-                      std::string(u8" Âñδ ωλèñ \"'ƨ ářè ïñ ƭλè ƨƭřïñϱ, áℓôñϱ ωïƭλ # \""));
-
-    const auto bit = toml::get<toml::Table>(hard.at(std::string(u8"βïƭ#")));
-    BOOST_CHECK_EQUAL(toml::get<std::string>(bit.at(std::string(u8"ωλáƭ?"))),
-                      std::string(u8"Ýôú δôñ'ƭ ƭλïñƙ ƨô₥è úƨèř ωôñ'ƭ δô ƭλáƭ?"));
-    const std::vector<std::string> expected_multi_line_array{"]"};
-    BOOST_CHECK(toml::get<std::vector<std::string>>(bit.at("multi_line_array")) ==
-                expected_multi_line_array);
-
-}
-#endif

tests/test_result.cpp

@@ -1,56 +1,57 @@
-#define BOOST_TEST_MODULE "test_result"
-#include <boost/test/unit_test.hpp>
-#include <iostream>
 #include <toml/result.hpp>
 
+#include "unit_test.hpp"
+
+#include <iostream>
+
 BOOST_AUTO_TEST_CASE(test_construct)
 {
     {
         auto s = toml::ok(42);
         toml::result<int, std::string> result(s);
-        BOOST_CHECK(!!result);
-        BOOST_CHECK(result.is_ok());
-        BOOST_CHECK(!result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap(), 42);
+        BOOST_TEST(!!result);
+        BOOST_TEST(result.is_ok());
+        BOOST_TEST(!result.is_err());
+        BOOST_TEST(result.unwrap() == 42);
     }
     {
         const auto s = toml::ok(42);
         toml::result<int, std::string> result(s);
-        BOOST_CHECK(!!result);
-        BOOST_CHECK(result.is_ok());
-        BOOST_CHECK(!result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap(), 42);
+        BOOST_TEST(!!result);
+        BOOST_TEST(result.is_ok());
+        BOOST_TEST(!result.is_err());
+        BOOST_TEST(result.unwrap() == 42);
     }
     {
         toml::result<int, std::string> result(toml::ok(42));
-        BOOST_CHECK(!!result);
-        BOOST_CHECK(result.is_ok());
-        BOOST_CHECK(!result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap(), 42);
+        BOOST_TEST(!!result);
+        BOOST_TEST(result.is_ok());
+        BOOST_TEST(!result.is_err());
+        BOOST_TEST(result.unwrap() == 42);
     }
 
     {
         auto f = toml::err<std::string>("foobar");
         toml::result<int, std::string> result(f);
-        BOOST_CHECK(!result);
-        BOOST_CHECK(!result.is_ok());
-        BOOST_CHECK(result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap_err(), "foobar");
+        BOOST_TEST(!result);
+        BOOST_TEST(!result.is_ok());
+        BOOST_TEST(result.is_err());
+        BOOST_TEST(result.unwrap_err() == "foobar");
     }
     {
         const auto f = toml::err<std::string>("foobar");
         toml::result<int, std::string> result(f);
-        BOOST_CHECK(!result);
-        BOOST_CHECK(!result.is_ok());
-        BOOST_CHECK(result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap_err(), "foobar");
+        BOOST_TEST(!result);
+        BOOST_TEST(!result.is_ok());
+        BOOST_TEST(result.is_err());
+        BOOST_TEST(result.unwrap_err() == "foobar");
     }
     {
         toml::result<int, std::string> result(toml::err<std::string>("foobar"));
-        BOOST_CHECK(!result);
-        BOOST_CHECK(!result.is_ok());
-        BOOST_CHECK(result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap_err(), "foobar");
+        BOOST_TEST(!result);
+        BOOST_TEST(!result.is_ok());
+        BOOST_TEST(result.is_err());
+        BOOST_TEST(result.unwrap_err() == "foobar");
     }
 }
 
@@ -59,54 +60,54 @@ BOOST_AUTO_TEST_CASE(test_assignment)
     {
         toml::result<int, std::string> result(toml::err<std::string>("foobar"));
         result = toml::ok(42);
-        BOOST_CHECK(!!result);
-        BOOST_CHECK(result.is_ok());
-        BOOST_CHECK(!result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap(), 42);
+        BOOST_TEST(!!result);
+        BOOST_TEST(result.is_ok());
+        BOOST_TEST(!result.is_err());
+        BOOST_TEST(result.unwrap() == 42);
     }
     {
         toml::result<int, std::string> result(toml::err<std::string>("foobar"));
         auto s = toml::ok(42);
         result = s;
-        BOOST_CHECK(!!result);
-        BOOST_CHECK(result.is_ok());
-        BOOST_CHECK(!result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap(), 42);
+        BOOST_TEST(!!result);
+        BOOST_TEST(result.is_ok());
+        BOOST_TEST(!result.is_err());
+        BOOST_TEST(result.unwrap() == 42);
     }
     {
         toml::result<int, std::string> result(toml::err<std::string>("foobar"));
         const auto s = toml::ok(42);
         result = s;
-        BOOST_CHECK(!!result);
-        BOOST_CHECK(result.is_ok());
-        BOOST_CHECK(!result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap(), 42);
+        BOOST_TEST(!!result);
+        BOOST_TEST(result.is_ok());
+        BOOST_TEST(!result.is_err());
+        BOOST_TEST(result.unwrap() == 42);
     }
     {
         toml::result<int, std::string> result(toml::err<std::string>("foobar"));
         result = toml::err<std::string>("hoge");
-        BOOST_CHECK(!result);
-        BOOST_CHECK(!result.is_ok());
-        BOOST_CHECK(result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap_err(), "hoge");
+        BOOST_TEST(!result);
+        BOOST_TEST(!result.is_ok());
+        BOOST_TEST(result.is_err());
+        BOOST_TEST(result.unwrap_err() == "hoge");
     }
     {
         toml::result<int, std::string> result(toml::err<std::string>("foobar"));
         auto f = toml::err<std::string>("hoge");
         result = f;
-        BOOST_CHECK(!result);
-        BOOST_CHECK(!result.is_ok());
-        BOOST_CHECK(result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap_err(), "hoge");
+        BOOST_TEST(!result);
+        BOOST_TEST(!result.is_ok());
+        BOOST_TEST(result.is_err());
+        BOOST_TEST(result.unwrap_err() == "hoge");
     }
     {
         toml::result<int, std::string> result(toml::err<std::string>("foobar"));
         const auto f = toml::err<std::string>("hoge");
         result = f;
-        BOOST_CHECK(!result);
-        BOOST_CHECK(!result.is_ok());
-        BOOST_CHECK(result.is_err());
-        BOOST_CHECK_EQUAL(result.unwrap_err(), "hoge");
+        BOOST_TEST(!result);
+        BOOST_TEST(!result.is_ok());
+        BOOST_TEST(result.is_err());
+        BOOST_TEST(result.unwrap_err() == "hoge");
     }
 }
 
@@ -119,10 +120,10 @@ BOOST_AUTO_TEST_CASE(test_map)
                     return i * 2;
                 });
 
-        BOOST_CHECK(!!mapped);
-        BOOST_CHECK(mapped.is_ok());
-        BOOST_CHECK(!mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap(), 42 * 2);
+        BOOST_TEST(!!mapped);
+        BOOST_TEST(mapped.is_ok());
+        BOOST_TEST(!mapped.is_err());
+        BOOST_TEST(mapped.unwrap() == 42 * 2);
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -132,10 +133,10 @@ BOOST_AUTO_TEST_CASE(test_map)
                     return *i;
                 });
 
-        BOOST_CHECK(!!mapped);
-        BOOST_CHECK(mapped.is_ok());
-        BOOST_CHECK(!mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap(), 42);
+        BOOST_TEST(!!mapped);
+        BOOST_TEST(mapped.is_ok());
+        BOOST_TEST(!mapped.is_err());
+        BOOST_TEST(mapped.unwrap() == 42);
     }
     {
         const toml::result<int, std::string> result(toml::err<std::string>("hoge"));
@@ -144,10 +145,10 @@ BOOST_AUTO_TEST_CASE(test_map)
                     return i * 2;
                 });
 
-        BOOST_CHECK(!mapped);
-        BOOST_CHECK(!mapped.is_ok());
-        BOOST_CHECK(mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap_err(), "hoge");
+        BOOST_TEST(!mapped);
+        BOOST_TEST(!mapped.is_ok());
+        BOOST_TEST(mapped.is_err());
+        BOOST_TEST(mapped.unwrap_err() == "hoge");
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -157,10 +158,10 @@ BOOST_AUTO_TEST_CASE(test_map)
                     return *i;
                 });
 
-        BOOST_CHECK(!mapped);
-        BOOST_CHECK(!mapped.is_ok());
-        BOOST_CHECK(mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap_err(), "hoge");
+        BOOST_TEST(!mapped);
+        BOOST_TEST(!mapped.is_ok());
+        BOOST_TEST(mapped.is_err());
+        BOOST_TEST(mapped.unwrap_err() == "hoge");
     }
 }
 
@@ -173,10 +174,10 @@ BOOST_AUTO_TEST_CASE(test_map_err)
                     return s + s;
                 });
 
-        BOOST_CHECK(!!mapped);
-        BOOST_CHECK(mapped.is_ok());
-        BOOST_CHECK(!mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap(), 42);
+        BOOST_TEST(!!mapped);
+        BOOST_TEST(mapped.is_ok());
+        BOOST_TEST(!mapped.is_err());
+        BOOST_TEST(mapped.unwrap() == 42);
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -186,10 +187,10 @@ BOOST_AUTO_TEST_CASE(test_map_err)
                     return s + s;
                 });
 
-        BOOST_CHECK(!!mapped);
-        BOOST_CHECK(mapped.is_ok());
-        BOOST_CHECK(!mapped.is_err());
-        BOOST_CHECK_EQUAL(*(mapped.unwrap()), 42);
+        BOOST_TEST(!!mapped);
+        BOOST_TEST(mapped.is_ok());
+        BOOST_TEST(!mapped.is_err());
+        BOOST_TEST(*(mapped.unwrap()) == 42);
     }
     {
         const toml::result<int, std::string> result(toml::err<std::string>("hoge"));
@@ -197,10 +198,10 @@ BOOST_AUTO_TEST_CASE(test_map_err)
                 [](const std::string s) -> std::string {
                     return s + s;
                 });
-        BOOST_CHECK(!mapped);
-        BOOST_CHECK(!mapped.is_ok());
-        BOOST_CHECK(mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap_err(), "hogehoge");
+        BOOST_TEST(!mapped);
+        BOOST_TEST(!mapped.is_ok());
+        BOOST_TEST(mapped.is_err());
+        BOOST_TEST(mapped.unwrap_err() == "hogehoge");
     }
     {
         toml::result<int, std::unique_ptr<std::string>>
@@ -210,10 +211,10 @@ BOOST_AUTO_TEST_CASE(test_map_err)
                     return *p;
                 });
 
-        BOOST_CHECK(!mapped);
-        BOOST_CHECK(!mapped.is_ok());
-        BOOST_CHECK(mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap_err(), "hoge");
+        BOOST_TEST(!mapped);
+        BOOST_TEST(!mapped.is_ok());
+        BOOST_TEST(mapped.is_err());
+        BOOST_TEST(mapped.unwrap_err() == "hoge");
     }
 }
 
@@ -226,7 +227,7 @@ BOOST_AUTO_TEST_CASE(test_map_or_else)
                     return i * 2;
                 }, 54);
 
-        BOOST_CHECK_EQUAL(mapped, 42 * 2);
+        BOOST_TEST(mapped == 42 * 2);
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -236,7 +237,7 @@ BOOST_AUTO_TEST_CASE(test_map_or_else)
                     return *i;
                 }, 54);
 
-        BOOST_CHECK_EQUAL(mapped, 42);
+        BOOST_TEST(mapped == 42);
     }
     {
         const toml::result<int, std::string> result(toml::err<std::string>("hoge"));
@@ -245,7 +246,7 @@ BOOST_AUTO_TEST_CASE(test_map_or_else)
                     return i * 2;
                 }, 54);
 
-        BOOST_CHECK_EQUAL(mapped, 54);
+        BOOST_TEST(mapped == 54);
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -255,7 +256,7 @@ BOOST_AUTO_TEST_CASE(test_map_or_else)
                     return *i;
                 }, 54);
 
-        BOOST_CHECK_EQUAL(mapped, 54);
+        BOOST_TEST(mapped == 54);
     }
 }
 
@@ -268,7 +269,7 @@ BOOST_AUTO_TEST_CASE(test_map_err_or_else)
                     return i + i;
                 }, "foobar");
 
-        BOOST_CHECK_EQUAL(mapped, "foobar");
+        BOOST_TEST(mapped == "foobar");
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -278,7 +279,7 @@ BOOST_AUTO_TEST_CASE(test_map_err_or_else)
                     return i + i;
                 }, "foobar");
 
-        BOOST_CHECK_EQUAL(mapped, "foobar");
+        BOOST_TEST(mapped == "foobar");
     }
     {
         const toml::result<int, std::string> result(toml::err<std::string>("hoge"));
@@ -287,7 +288,7 @@ BOOST_AUTO_TEST_CASE(test_map_err_or_else)
                     return i + i;
                 }, "foobar");
 
-        BOOST_CHECK_EQUAL(mapped, "hogehoge");
+        BOOST_TEST(mapped == "hogehoge");
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -297,7 +298,7 @@ BOOST_AUTO_TEST_CASE(test_map_err_or_else)
                     return i + i;
                 }, "foobar");
 
-        BOOST_CHECK_EQUAL(mapped, "hogehoge");
+        BOOST_TEST(mapped == "hogehoge");
     }
 }
 
@@ -311,10 +312,10 @@ BOOST_AUTO_TEST_CASE(test_and_then)
                     return toml::ok(i * 2);
                 });
 
-        BOOST_CHECK(!!mapped);
-        BOOST_CHECK(mapped.is_ok());
-        BOOST_CHECK(!mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap(), 42 * 2);
+        BOOST_TEST(!!mapped);
+        BOOST_TEST(mapped.is_ok());
+        BOOST_TEST(!mapped.is_err());
+        BOOST_TEST(mapped.unwrap() == 42 * 2);
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -324,10 +325,10 @@ BOOST_AUTO_TEST_CASE(test_and_then)
                     return toml::ok(*i);
                 });
 
-        BOOST_CHECK(!!mapped);
-        BOOST_CHECK(mapped.is_ok());
-        BOOST_CHECK(!mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap(), 42);
+        BOOST_TEST(!!mapped);
+        BOOST_TEST(mapped.is_ok());
+        BOOST_TEST(!mapped.is_err());
+        BOOST_TEST(mapped.unwrap() == 42);
     }
     {
         const toml::result<int, std::string> result(toml::err<std::string>("hoge"));
@@ -336,10 +337,10 @@ BOOST_AUTO_TEST_CASE(test_and_then)
                     return toml::ok(i * 2);
                 });
 
-        BOOST_CHECK(!mapped);
-        BOOST_CHECK(!mapped.is_ok());
-        BOOST_CHECK(mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap_err(), "hoge");
+        BOOST_TEST(!mapped);
+        BOOST_TEST(!mapped.is_ok());
+        BOOST_TEST(mapped.is_err());
+        BOOST_TEST(mapped.unwrap_err() == "hoge");
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -349,10 +350,10 @@ BOOST_AUTO_TEST_CASE(test_and_then)
                     return toml::ok(*i);
                 });
 
-        BOOST_CHECK(!mapped);
-        BOOST_CHECK(!mapped.is_ok());
-        BOOST_CHECK(mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap_err(), "hoge");
+        BOOST_TEST(!mapped);
+        BOOST_TEST(!mapped.is_ok());
+        BOOST_TEST(mapped.is_err());
+        BOOST_TEST(mapped.unwrap_err() == "hoge");
     }
 }
 
@@ -365,10 +366,10 @@ BOOST_AUTO_TEST_CASE(test_or_else)
                     return toml::err(s + s);
                 });
 
-        BOOST_CHECK(!!mapped);
-        BOOST_CHECK(mapped.is_ok());
-        BOOST_CHECK(!mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap(), 42);
+        BOOST_TEST(!!mapped);
+        BOOST_TEST(mapped.is_ok());
+        BOOST_TEST(!mapped.is_err());
+        BOOST_TEST(mapped.unwrap() == 42);
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -378,10 +379,10 @@ BOOST_AUTO_TEST_CASE(test_or_else)
                     return toml::err(s + s);
                 });
 
-        BOOST_CHECK(!!mapped);
-        BOOST_CHECK(mapped.is_ok());
-        BOOST_CHECK(!mapped.is_err());
-        BOOST_CHECK_EQUAL(*mapped.unwrap(), 42);
+        BOOST_TEST(!!mapped);
+        BOOST_TEST(mapped.is_ok());
+        BOOST_TEST(!mapped.is_err());
+        BOOST_TEST(*mapped.unwrap() == 42);
     }
     {
         const toml::result<int, std::string> result(toml::err<std::string>("hoge"));
@@ -390,10 +391,10 @@ BOOST_AUTO_TEST_CASE(test_or_else)
                     return toml::err(s + s);
                 });
 
-        BOOST_CHECK(!mapped);
-        BOOST_CHECK(!mapped.is_ok());
-        BOOST_CHECK(mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap_err(), "hogehoge");
+        BOOST_TEST(!mapped);
+        BOOST_TEST(!mapped.is_ok());
+        BOOST_TEST(mapped.is_err());
+        BOOST_TEST(mapped.unwrap_err() == "hogehoge");
     }
     {
         toml::result<std::unique_ptr<int>, std::string>
@@ -403,10 +404,10 @@ BOOST_AUTO_TEST_CASE(test_or_else)
                     return toml::err(s + s);
                 });
 
-        BOOST_CHECK(!mapped);
-        BOOST_CHECK(!mapped.is_ok());
-        BOOST_CHECK(mapped.is_err());
-        BOOST_CHECK_EQUAL(mapped.unwrap_err(), "hogehoge");
+        BOOST_TEST(!mapped);
+        BOOST_TEST(!mapped.is_ok());
+        BOOST_TEST(mapped.is_err());
+        BOOST_TEST(mapped.unwrap_err() == "hogehoge");
     }
 }
 
@@ -416,10 +417,10 @@ BOOST_AUTO_TEST_CASE(test_and_or_other)
         const toml::result<int, std::string> r1(toml::ok(42));
         const toml::result<int, std::string> r2(toml::err<std::string>("foo"));
 
-        BOOST_CHECK_EQUAL(r1,    r1.or_other(r2));
-        BOOST_CHECK_EQUAL(r2,    r1.and_other(r2));
-        BOOST_CHECK_EQUAL(42,    r1.or_other(r2).unwrap());
-        BOOST_CHECK_EQUAL("foo", r1.and_other(r2).unwrap_err());
+        BOOST_TEST(r1 ==    r1.or_other(r2));
+        BOOST_TEST(r2 ==    r1.and_other(r2));
+        BOOST_TEST(42 ==    r1.or_other(r2).unwrap());
+        BOOST_TEST("foo" == r1.and_other(r2).unwrap_err());
     }
     {
         auto r1_gen = []() -> toml::result<int, std::string> {
@@ -431,11 +432,9 @@ BOOST_AUTO_TEST_CASE(test_and_or_other)
         const auto r3 = r1_gen();
         const auto r4 = r2_gen();
 
-        BOOST_CHECK_EQUAL(r3, r1_gen().or_other (r2_gen()));
-        BOOST_CHECK_EQUAL(r4, r1_gen().and_other(r2_gen()));
-        BOOST_CHECK_EQUAL(42,    r1_gen().or_other (r2_gen()).unwrap());
-        BOOST_CHECK_EQUAL("foo", r1_gen().and_other(r2_gen()).unwrap_err());
+        BOOST_TEST(r3 == r1_gen().or_other (r2_gen()));
+        BOOST_TEST(r4 == r1_gen().and_other(r2_gen()));
+        BOOST_TEST(42 ==    r1_gen().or_other (r2_gen()).unwrap());
+        BOOST_TEST("foo" == r1_gen().and_other(r2_gen()).unwrap_err());
     }
 }
-
-

tests/test_serialize_file.cpp

@@ -0,0 +1,405 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+#include <deque>
+#include <fstream>
+#include <iostream>
+#include <map>
+#include <sstream>
+
+#include <clocale>
+
+template<typename Comment,
+         template<typename ...> class Table,
+         template<typename ...> class Array>
+bool has_comment_inside(const toml::basic_value<Comment, Table, Array>& v)
+{
+    if(!v.comments().empty())
+    {
+        return false;
+    }
+    // v itself does not have a comment.
+    if(v.is_array())
+    {
+        for(const auto& x : v.as_array())
+        {
+            if(has_comment_inside(x))
+            {
+                return false;
+            }
+        }
+    }
+    if(v.is_table())
+    {
+        for(const auto& x : v.as_table())
+        {
+            if(has_comment_inside(x.second))
+            {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+BOOST_AUTO_TEST_CASE(test_example)
+{
+    const auto data = toml::parse(testinput("example.toml"));
+    {
+        std::ofstream ofs("tmp1.toml");
+        ofs << std::setw(80) << data;
+    }
+
+    auto serialized = toml::parse("tmp1.toml");
+    {
+        auto& owner = toml::find(serialized, "owner");
+        auto& bio   = toml::find<std::string>(owner, "bio");
+        const auto CR = std::find(bio.begin(), bio.end(), '\r');
+        if(CR != bio.end())
+        {
+            bio.erase(CR);
+        }
+    }
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_example_map_dq)
+{
+    const auto data = toml::parse<toml::discard_comments, std::map, std::deque>(
+            testinput("example.toml"));
+    {
+        std::ofstream ofs("tmp1_map_dq.toml");
+        ofs << std::setw(80) << data;
+    }
+
+    auto serialized = toml::parse<toml::discard_comments, std::map, std::deque>(
+            "tmp1_map_dq.toml");
+    {
+        auto& owner = toml::find(serialized, "owner");
+        auto& bio   = toml::find<std::string>(owner, "bio");
+        const auto CR = std::find(bio.begin(), bio.end(), '\r');
+        if(CR != bio.end())
+        {
+            bio.erase(CR);
+        }
+    }
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_example_with_comment)
+{
+    const auto data = toml::parse<toml::preserve_comments>(testinput("example.toml"));
+    {
+        std::ofstream ofs("tmp1_com.toml");
+        ofs << std::setw(80) << data;
+    }
+
+    auto serialized = toml::parse<toml::preserve_comments>("tmp1_com.toml");
+    {
+        auto& owner = toml::find(serialized, "owner");
+        auto& bio   = toml::find<std::string>(owner, "bio");
+        const auto CR = std::find(bio.begin(), bio.end(), '\r');
+        if(CR != bio.end())
+        {
+            bio.erase(CR);
+        }
+    }
+    BOOST_TEST(data == serialized);
+    {
+        std::ofstream ofs("tmp1_com1.toml");
+        ofs << std::setw(80) << serialized;
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_example_with_comment_nocomment)
+{
+    {
+        const auto data = toml::parse<toml::preserve_comments>(testinput("example.toml"));
+        {
+            std::ofstream ofs("tmp1_com_nocomment.toml");
+            ofs << std::setw(80) << toml::nocomment << data;
+        }
+        const auto serialized = toml::parse<toml::preserve_comments>("tmp1_com_nocomment.toml");
+        // check no comment exist
+        BOOST_TEST(!has_comment_inside(serialized));
+    }
+    {
+        const auto data_nocomment = toml::parse<toml::discard_comments>(testinput("example.toml"));
+        auto serialized = toml::parse<toml::discard_comments>("tmp1_com_nocomment.toml");
+        {
+            auto& owner = toml::find(serialized, "owner");
+            auto& bio   = toml::find<std::string>(owner, "bio");
+            const auto CR = std::find(bio.begin(), bio.end(), '\r');
+            if(CR != bio.end())
+            {
+                bio.erase(CR);
+            }
+        }
+        // check collectly serialized
+        BOOST_TEST(data_nocomment == serialized);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_example_with_comment_map_dq)
+{
+    const auto data = toml::parse<toml::preserve_comments, std::map, std::deque>(
+            testinput("example.toml"));
+    {
+        std::ofstream ofs("tmp1_com_map_dq.toml");
+        ofs << std::setw(80) << data;
+    }
+
+    auto serialized = toml::parse<toml::preserve_comments, std::map, std::deque>(
+            "tmp1_com_map_dq.toml");
+    {
+        auto& owner = toml::find(serialized, "owner");
+        auto& bio   = toml::find<std::string>(owner, "bio");
+        const auto CR = std::find(bio.begin(), bio.end(), '\r');
+        if(CR != bio.end())
+        {
+            bio.erase(CR);
+        }
+    }
+    BOOST_TEST(data == serialized);
+    {
+        std::ofstream ofs("tmp1_com1_map_dq.toml");
+        ofs << std::setw(80) << serialized;
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_example_with_comment_map_dq_nocomment)
+{
+    {
+        const auto data = toml::parse<toml::preserve_comments, std::map, std::deque>(testinput("example.toml"));
+        {
+            std::ofstream ofs("tmp1_com_map_dq_nocomment.toml");
+            ofs << std::setw(80) << toml::nocomment << data;
+        }
+        const auto serialized = toml::parse<toml::preserve_comments, std::map, std::deque>("tmp1_com_map_dq_nocomment.toml");
+        BOOST_TEST(!has_comment_inside(serialized));
+    }
+    {
+        const auto data_nocomment = toml::parse<toml::discard_comments>(testinput("example.toml"));
+        auto serialized = toml::parse<toml::discard_comments>("tmp1_com_map_dq_nocomment.toml");
+        {
+            auto& owner = toml::find(serialized, "owner");
+            auto& bio   = toml::find<std::string>(owner, "bio");
+            const auto CR = std::find(bio.begin(), bio.end(), '\r');
+            if(CR != bio.end())
+            {
+                bio.erase(CR);
+            }
+        }
+        BOOST_TEST(data_nocomment == serialized);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_fruit)
+{
+    const auto data = toml::parse(testinput("fruit.toml"));
+    {
+        std::ofstream ofs("tmp2.toml");
+        ofs << std::setw(80) << data;
+    }
+    const auto serialized = toml::parse("tmp2.toml");
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_fruit_map_dq)
+{
+    const auto data = toml::parse<toml::discard_comments, std::map, std::deque>(
+            testinput("fruit.toml"));
+    {
+        std::ofstream ofs("tmp2.toml");
+        ofs << std::setw(80) << data;
+    }
+    const auto serialized = toml::parse<toml::discard_comments, std::map, std::deque>(
+            "tmp2.toml");
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_fruit_with_comments)
+{
+    const auto data = toml::parse<toml::preserve_comments>(testinput("fruit.toml"));
+    {
+        std::ofstream ofs("tmp2_com.toml");
+        ofs << std::setw(80) << data;
+    }
+    const auto serialized = toml::parse<toml::preserve_comments>("tmp2_com.toml");
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_fruit_with_comments_map_dq)
+{
+    const auto data = toml::parse<toml::preserve_comments, std::map, std::deque>(
+            testinput("fruit.toml"));
+    {
+        std::ofstream ofs("tmp2_com.toml");
+        ofs << std::setw(80) << data;
+    }
+    const auto serialized = toml::parse<toml::preserve_comments, std::map, std::deque>("tmp2_com.toml");
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_hard_example)
+{
+    const auto data = toml::parse(testinput("hard_example.toml"));
+    {
+        std::ofstream ofs("tmp3.toml");
+        ofs << std::setw(80) << data;
+    }
+    const auto serialized = toml::parse("tmp3.toml");
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_hard_example_map_dq)
+{
+    const auto data = toml::parse<toml::discard_comments, std::map, std::deque>(
+            testinput("hard_example.toml"));
+    {
+        std::ofstream ofs("tmp3.toml");
+        ofs << std::setw(80) << data;
+    }
+    const auto serialized = toml::parse<toml::discard_comments, std::map, std::deque>(
+            "tmp3.toml");
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_hard_example_with_comment)
+{
+    const auto data = toml::parse<toml::preserve_comments, std::map, std::deque>(
+            testinput("hard_example.toml"));
+    {
+        std::ofstream ofs("tmp3_com.toml");
+        ofs << std::setw(80) << data;
+    }
+    const auto serialized = toml::parse<toml::preserve_comments, std::map, std::deque>(
+            "tmp3_com.toml");
+    {
+        std::ofstream ofs("tmp3_com1.toml");
+        ofs << std::setw(80) << serialized;
+    }
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_format_key)
+{
+    {
+        const toml::key key("normal_bare-key");
+        BOOST_TEST("normal_bare-key" == toml::format_key(key));
+    }
+    {
+        const toml::key key("key.include.dots");
+        BOOST_TEST("\"key.include.dots\"" == toml::format_key(key));
+    }
+    {
+        const toml::key key("key-include-unicode-\xE3\x81\x82");
+        BOOST_TEST("\"key-include-unicode-\xE3\x81\x82\"" == toml::format_key(key));
+    }
+    {
+        const toml::key key("special-chars-\\-\"-\b-\f-\r-\n-\t");
+        BOOST_TEST("\"special-chars-\\\\-\\\"-\\b-\\f-\\r-\\n-\\t\"" == toml::format_key(key));
+    }
+}
+
+// In toml11, an implicitly-defined value does not have any comments.
+// So, in the following file,
+// ```toml
+// # comment
+// [[array-of-tables]]
+// foo = "bar"
+// ```
+// The array named "array-of-tables" does not have the comment, but the first
+// element of the array has. That means that, the above file is equivalent to
+// the following.
+// ```toml
+// array-of-tables = [
+//     # comment
+//     {foo = "bar"},
+// ]
+// ```
+// If the array itself has a comment (value_has_comment_ == true), we should try
+// to make it inline.
+// ```toml
+// # comment about array
+// array-of-tables = [
+//   # comment about table element
+//   {foo = "bar"}
+// ]
+// ```
+// If it is formatted as a multiline table, the two comments becomes
+// indistinguishable.
+// ```toml
+// # comment about array
+// # comment about table element
+// [[array-of-tables]]
+// foo = "bar"
+// ```
+// So we need to try to make it inline, and it force-inlines regardless
+// of the line width limit.
+//     It may fail if the element of a table has comment. In that case,
+// the array-of-tables will be formatted as a multiline table.
+BOOST_AUTO_TEST_CASE(test_distinguish_comment)
+{
+    const std::string str = R"(# comment about array itself
+array_of_table = [
+    # comment about the first element (table)
+    {key = "value"},
+])";
+    std::istringstream iss(str);
+    const auto data = toml::parse<toml::preserve_comments>(iss);
+    const auto serialized = toml::format(data, /*width = */ 0);
+
+    std::istringstream reparse(serialized);
+    const auto parsed = toml::parse<toml::preserve_comments>(reparse);
+
+    BOOST_TEST(parsed.at("array_of_table").comments().size()  == 1u);
+    BOOST_TEST(parsed.at("array_of_table").comments().front() == " comment about array itself");
+    BOOST_TEST(parsed.at("array_of_table").at(0).comments().size()  == 1u);
+    BOOST_TEST(parsed.at("array_of_table").at(0).comments().front() == " comment about the first element (table)");
+}
+
+
+BOOST_AUTO_TEST_CASE(test_serialize_under_locale)
+{
+    // avoid null init (setlocale returns null when it failed)
+    std::string setloc(std::setlocale(LC_ALL, nullptr));
+
+    // fr_FR is a one of locales that uses `,` as a decimal separator.
+    if(const char* try_hyphen = std::setlocale(LC_ALL, "fr_FR.UTF-8"))
+    {
+        setloc = std::string(try_hyphen);
+    }
+    else if(const char* try_nohyphen = std::setlocale(LC_ALL, "fr_FR.utf8"))
+    {
+        setloc = std::string(try_nohyphen);
+    }
+    // In some envs, fr_FR locale has not been installed. Tests must work even in such a case.
+//     else
+//     {
+//         BOOST_TEST(false);
+//     }
+    BOOST_TEST_MESSAGE("current locale at the beginning of the test = " << setloc);
+
+    const std::string str = R"(
+pi        = 3.14159
+large_int = 1234567890
+)";
+    std::istringstream iss(str);
+    const auto ref = toml::parse(iss);
+    const auto serialized_str = toml::format(ref, /*width = */ 80);
+
+    BOOST_TEST_MESSAGE("serialized = " << serialized_str);
+
+    std::istringstream serialized_iss(serialized_str);
+    const auto serialized_ref = toml::parse(serialized_iss);
+
+    BOOST_TEST(serialized_ref.at("pi").as_floating() == ref.at("pi").as_floating());
+    BOOST_TEST(serialized_ref.at("large_int").as_integer() == ref.at("large_int").as_integer());
+
+    const std::string endloc(std::setlocale(LC_ALL, nullptr));
+    BOOST_TEST_MESSAGE("current locale at the end of the test = " << endloc);
+    // check if serializer change global locale
+    BOOST_TEST(setloc == endloc);
+}

tests/test_string.cpp

@@ -0,0 +1,153 @@
+#include <toml.hpp>
+
+#include "unit_test.hpp"
+
+BOOST_AUTO_TEST_CASE(test_basic_string)
+{
+    {
+        const toml::string str("basic string");
+        std::ostringstream oss;
+        oss << str;
+        BOOST_TEST(oss.str() == "\"basic string\"");
+    }
+    {
+        const std::string  s1 ("basic string");
+        const toml::string str(s1);
+        std::ostringstream oss;
+        oss << str;
+        BOOST_TEST(oss.str() == "\"basic string\"");
+    }
+    {
+        const toml::string str("basic string", toml::string_t::basic);
+        std::ostringstream oss;
+        oss << str;
+        BOOST_TEST(oss.str() == "\"basic string\"");
+    }
+    {
+        const std::string  s1 ("basic string");
+        const toml::string str(s1, toml::string_t::basic);
+        std::ostringstream oss;
+        oss << str;
+        BOOST_TEST(oss.str() == "\"basic string\"");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_basic_ml_string)
+{
+    {
+        const toml::string str("basic\nstring");
+        std::ostringstream oss1;
+        oss1 << str;
+        std::ostringstream oss2;
+        oss2 << "\"\"\"\nbasic\nstring\\\n\"\"\"";
+        BOOST_TEST(oss1.str() == oss2.str());
+    }
+    {
+        const std::string  s1 ("basic\nstring");
+        const toml::string str(s1);
+        std::ostringstream oss1;
+        oss1 << str;
+        std::ostringstream oss2;
+        oss2 << "\"\"\"\nbasic\nstring\\\n\"\"\"";
+        BOOST_TEST(oss1.str() == oss2.str());
+    }
+    {
+        const toml::string str("basic\nstring", toml::string_t::basic);
+        std::ostringstream oss1;
+        oss1 << str;
+        std::ostringstream oss2;
+        oss2 << "\"\"\"\nbasic\nstring\\\n\"\"\"";
+        BOOST_TEST(oss1.str() == oss2.str());
+
+    }
+    {
+        const std::string  s1 ("basic\nstring");
+        const toml::string str(s1, toml::string_t::basic);
+        std::ostringstream oss1;
+        oss1 << str;
+        std::ostringstream oss2;
+        oss2 << "\"\"\"\nbasic\nstring\\\n\"\"\"";
+        BOOST_TEST(oss1.str() == oss2.str());
+    }
+}
+
+
+BOOST_AUTO_TEST_CASE(test_literal_string)
+{
+    {
+        const toml::string str("literal string", toml::string_t::literal);
+        std::ostringstream oss;
+        oss << str;
+        BOOST_TEST(oss.str() == "'literal string'");
+    }
+    {
+        const std::string  s1 ("literal string");
+        const toml::string str(s1, toml::string_t::literal);
+        std::ostringstream oss;
+        oss << str;
+        BOOST_TEST(oss.str() == "'literal string'");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_literal_ml_string)
+{
+    {
+        const toml::string str("literal\nstring", toml::string_t::literal);
+        std::ostringstream oss1;
+        oss1 << str;
+        std::ostringstream oss2;
+        oss2 << "'''\nliteral\nstring'''";
+        BOOST_TEST(oss1.str() == oss2.str());
+
+    }
+    {
+        const std::string  s1 ("literal\nstring");
+        const toml::string str(s1, toml::string_t::literal);
+        std::ostringstream oss1;
+        oss1 << str;
+        std::ostringstream oss2;
+        oss2 << "'''\nliteral\nstring'''";
+        BOOST_TEST(oss1.str() == oss2.str());
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_string_add_assign)
+{
+    // string literal
+    {
+        toml::string str("foo");
+        str += "bar";
+        BOOST_TEST(str.str == "foobar");
+    }
+    // std::string
+    {
+        toml::string str("foo");
+        std::string str2("bar");
+        str += str2;
+        BOOST_TEST(str.str == "foobar");
+    }
+    // toml::string
+    {
+        toml::string str("foo");
+        toml::string str2("bar");
+        str += str2;
+        BOOST_TEST(str.str == "foobar");
+    }
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+    // std::string_view
+    {
+        toml::string str("foo");
+        str += std::string_view("bar");
+        BOOST_TEST(str == "foobar");
+    }
+#endif
+    // std::string += toml::string
+    {
+        std::string  str("foo");
+        toml::string str2("bar");
+        str += str2;
+        BOOST_TEST(str == "foobar");
+    }
+
+
+}

tests/test_to_toml.cpp

@@ -1,189 +0,0 @@
-#define BOOST_TEST_MODULE "test_to_toml"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
-#include <toml.hpp>
-#include <map>
-#include <list>
-
-BOOST_AUTO_TEST_CASE(test_value_boolean)
-{
-    toml::value v1 = toml::to_toml(true);
-    toml::value v2 = toml::to_toml(false);
-
-    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Boolean);
-    BOOST_CHECK_EQUAL(v2.type(), toml::value_t::Boolean);
-    BOOST_CHECK(v1.is(toml::value_t::Boolean));
-    BOOST_CHECK(v2.is(toml::value_t::Boolean));
-    BOOST_CHECK(v1.is<toml::Boolean>());
-    BOOST_CHECK(v2.is<toml::Boolean>());
-
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
-    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Boolean>(), false);
-}
-
-BOOST_AUTO_TEST_CASE(test_value_integer)
-{
-    toml::value v1 = toml::to_toml(-42);
-    toml::value v2 = toml::to_toml(42u);
-
-    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Integer);
-    BOOST_CHECK_EQUAL(v2.type(), toml::value_t::Integer);
-    BOOST_CHECK(v1.is(toml::value_t::Integer));
-    BOOST_CHECK(v2.is(toml::value_t::Integer));
-    BOOST_CHECK(v1.is<toml::Integer>());
-    BOOST_CHECK(v2.is<toml::Integer>());
-
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Integer>(), -42);
-    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Integer>(),  42u);
-}
-
-BOOST_AUTO_TEST_CASE(test_value_float)
-{
-    toml::value v1 = toml::to_toml(3.14);
-    toml::value v2 = toml::to_toml(3.14f);
-
-    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Float);
-    BOOST_CHECK_EQUAL(v2.type(), toml::value_t::Float);
-    BOOST_CHECK(v1.is(toml::value_t::Float));
-    BOOST_CHECK(v2.is(toml::value_t::Float));
-    BOOST_CHECK(v1.is<toml::Float>());
-    BOOST_CHECK(v2.is<toml::Float>());
-
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Float>(), 3.14);
-    BOOST_CHECK_CLOSE_FRACTION(v2.cast<toml::value_t::Float>(), 3.14, 1e-2);
-}
-
-BOOST_AUTO_TEST_CASE(test_value_string)
-{
-    toml::value v1 = toml::to_toml(std::string("foo"));
-    toml::value v2 = toml::to_toml(std::string("foo"), toml::string_t::literal);
-    toml::value v3 = toml::to_toml("foo");
-
-    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::String);
-    BOOST_CHECK_EQUAL(v2.type(), toml::value_t::String);
-    BOOST_CHECK_EQUAL(v3.type(), toml::value_t::String);
-    BOOST_CHECK(v1.is(toml::value_t::String));
-    BOOST_CHECK(v2.is(toml::value_t::String));
-    BOOST_CHECK(v3.is(toml::value_t::String));
-    BOOST_CHECK(v1.is<toml::String>());
-    BOOST_CHECK(v2.is<toml::String>());
-    BOOST_CHECK(v3.is<toml::String>());
-
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::String>(), "foo");
-    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::String>(), "foo");
-    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::String>(), "foo");
-}
-
-BOOST_AUTO_TEST_CASE(test_value_local_date)
-{
-    toml::value v1 = toml::to_toml(toml::local_date(2018, toml::month_t::Jan, 31));
-
-    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::LocalDate);
-    BOOST_CHECK(v1.is(toml::value_t::LocalDate));
-    BOOST_CHECK(v1.is<toml::LocalDate>());
-
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::LocalDate>(),
-                      toml::local_date(2018, toml::month_t::Jan, 31));
-}
-
-BOOST_AUTO_TEST_CASE(test_value_local_time)
-{
-    toml::value v1 = toml::to_toml(toml::local_time(12, 30, 45));
-    toml::value v2 = toml::to_toml(std::chrono::hours(12) + std::chrono::minutes(30) +
-                   std::chrono::seconds(45));
-
-    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::LocalTime);
-    BOOST_CHECK_EQUAL(v2.type(), toml::value_t::LocalTime);
-    BOOST_CHECK(v1.is(toml::value_t::LocalTime));
-    BOOST_CHECK(v2.is(toml::value_t::LocalTime));
-    BOOST_CHECK(v1.is<toml::LocalTime>());
-    BOOST_CHECK(v2.is<toml::LocalTime>());
-
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::LocalTime>(),
-                      toml::local_time(12, 30, 45));
-    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::LocalTime>(),
-                      toml::local_time(12, 30, 45));
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::LocalTime>(),
-                      v2.cast<toml::value_t::LocalTime>());
-}
-
-BOOST_AUTO_TEST_CASE(test_value_local_datetime)
-{
-    toml::value v1 = toml::to_toml(toml::local_datetime(
-                toml::local_date(2018, toml::month_t::Jan, 31),
-                toml::local_time(12, 30, 45)
-                ));
-
-    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::LocalDatetime);
-    BOOST_CHECK(v1.is(toml::value_t::LocalDatetime));
-    BOOST_CHECK(v1.is<toml::LocalDatetime>());
-
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::LocalDatetime>(),
-                      toml::local_datetime(
-                          toml::local_date(2018, toml::month_t::Jan, 31),
-                          toml::local_time(12, 30, 45)));
-}
-
-BOOST_AUTO_TEST_CASE(test_value_offset_datetime)
-{
-    toml::value v1 = toml::to_toml(toml::offset_datetime(
-                toml::local_date(2018, toml::month_t::Jan, 31),
-                toml::local_time(12, 30, 45),
-                toml::time_offset(9, 0)
-                ));
-
-    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::OffsetDatetime);
-    BOOST_CHECK(v1.is(toml::value_t::OffsetDatetime));
-    BOOST_CHECK(v1.is<toml::OffsetDatetime>());
-
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::OffsetDatetime>(),
-            toml::offset_datetime(
-                toml::local_date(2018, toml::month_t::Jan, 31),
-                toml::local_time(12, 30, 45),
-                toml::time_offset(9, 0)
-                ));
-}
-
-BOOST_AUTO_TEST_CASE(test_value_array)
-{
-    std::vector<int> v{1,2,3,4,5};
-    toml::value v1 = toml::to_toml(v);
-    toml::value v2 = toml::to_toml(6,7,8,9,0);
-
-    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Array);
-    BOOST_CHECK(v1.is(toml::value_t::Array));
-    BOOST_CHECK(v1.is<toml::Array>());
-
-    BOOST_CHECK_EQUAL(v2.type(), toml::value_t::Array);
-    BOOST_CHECK(v2.is(toml::value_t::Array));
-    BOOST_CHECK(v2.is<toml::Array>());
-
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(0).cast<toml::value_t::Integer>(), 1);
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(1).cast<toml::value_t::Integer>(), 2);
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(2).cast<toml::value_t::Integer>(), 3);
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(3).cast<toml::value_t::Integer>(), 4);
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(4).cast<toml::value_t::Integer>(), 5);
-
-    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(0).cast<toml::value_t::Integer>(), 6);
-    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(1).cast<toml::value_t::Integer>(), 7);
-    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(2).cast<toml::value_t::Integer>(), 8);
-    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(3).cast<toml::value_t::Integer>(), 9);
-    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(4).cast<toml::value_t::Integer>(), 0);
-}
-
-BOOST_AUTO_TEST_CASE(test_value_table)
-{
-    toml::value v1 = toml::to_toml({{"foo", 42}, {"bar", 3.14}, {"baz", "qux"}});
-
-    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Table);
-    BOOST_CHECK(v1.is(toml::value_t::Table));
-    BOOST_CHECK(v1.is<toml::Table>());
-
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Table>().at("foo").cast<toml::value_t::Integer>(),    42);
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Table>().at("bar").cast<toml::value_t::Float>(),      3.14);
-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Table>().at("baz").cast<toml::value_t::String>().str, "qux");
-}

tests/test_traits.cpp

@@ -1,21 +1,16 @@
-#define BOOST_TEST_MODULE "test_traits"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/types.hpp>
 
-#include <list>
-#include <forward_list>
-#include <deque>
+#include "unit_test.hpp"
+
 #include <array>
+#include <deque>
+#include <forward_list>
+#include <list>
 #include <map>
 #include <set>
+#include <string>
 #include <unordered_map>
 #include <unordered_set>
-#include <string>
 
 struct dummy_type{};
 
@@ -37,48 +32,48 @@ typedef std::unordered_map<std::string, dummy_type> std_unordered_map_type;
 
 BOOST_AUTO_TEST_CASE(test_has_xxx)
 {
-    BOOST_CHECK(toml::detail::has_iterator<std::list<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::has_iterator<std::forward_list<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::has_iterator<std::deque<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::has_iterator<std::vector<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::has_iterator<std::set<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::has_iterator<std::unordered_set<std::string>>::value);
-    BOOST_CHECK(toml::detail::has_iterator<std_array_type>::value);
-    BOOST_CHECK(toml::detail::has_iterator<std_map_type>::value);
-    BOOST_CHECK(toml::detail::has_iterator<std_unordered_map_type>::value);
-    BOOST_CHECK(toml::detail::has_iterator<dummy_container<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_iterator<std::list<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_iterator<std::forward_list<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_iterator<std::deque<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_iterator<std::vector<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_iterator<std::set<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_iterator<std::unordered_set<std::string>>::value);
+    BOOST_TEST(toml::detail::has_iterator<std_array_type>::value);
+    BOOST_TEST(toml::detail::has_iterator<std_map_type>::value);
+    BOOST_TEST(toml::detail::has_iterator<std_unordered_map_type>::value);
+    BOOST_TEST(toml::detail::has_iterator<dummy_container<dummy_type>>::value);
 
-    BOOST_CHECK(toml::detail::has_value_type<std::list<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::has_value_type<std::forward_list<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::has_value_type<std::deque<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::has_value_type<std::vector<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::has_value_type<std_array_type>::value);
-    BOOST_CHECK(toml::detail::has_value_type<std::set<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::has_value_type<std::unordered_set<std::string>>::value);
-    BOOST_CHECK(toml::detail::has_value_type<std_map_type>::value);
-    BOOST_CHECK(toml::detail::has_value_type<std_unordered_map_type>::value);
-    BOOST_CHECK(toml::detail::has_value_type<dummy_container<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_value_type<std::list<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_value_type<std::forward_list<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_value_type<std::deque<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_value_type<std::vector<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_value_type<std_array_type>::value);
+    BOOST_TEST(toml::detail::has_value_type<std::set<dummy_type>>::value);
+    BOOST_TEST(toml::detail::has_value_type<std::unordered_set<std::string>>::value);
+    BOOST_TEST(toml::detail::has_value_type<std_map_type>::value);
+    BOOST_TEST(toml::detail::has_value_type<std_unordered_map_type>::value);
+    BOOST_TEST(toml::detail::has_value_type<dummy_container<dummy_type>>::value);
 
-    BOOST_CHECK(toml::detail::has_key_type<std_map_type>::value);
-    BOOST_CHECK(toml::detail::has_key_type<std_unordered_map_type>::value);
-    BOOST_CHECK(toml::detail::has_mapped_type<std_map_type>::value);
-    BOOST_CHECK(toml::detail::has_mapped_type<std_unordered_map_type>::value);
+    BOOST_TEST(toml::detail::has_key_type<std_map_type>::value);
+    BOOST_TEST(toml::detail::has_key_type<std_unordered_map_type>::value);
+    BOOST_TEST(toml::detail::has_mapped_type<std_map_type>::value);
+    BOOST_TEST(toml::detail::has_mapped_type<std_unordered_map_type>::value);
 }
 
 BOOST_AUTO_TEST_CASE(test_is_xxx)
 {
-    BOOST_CHECK(toml::detail::is_container<std::list<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::is_container<std::forward_list<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::is_container<std::deque<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::is_container<std::vector<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::is_container<std_array_type>::value);
-    BOOST_CHECK(toml::detail::is_container<std::set<dummy_type>>::value);
-    BOOST_CHECK(toml::detail::is_container<std::unordered_set<std::string>>::value);
-    BOOST_CHECK(toml::detail::is_container<dummy_container<dummy_type>>::value);
+    BOOST_TEST(toml::detail::is_container<std::list<dummy_type>>::value);
+    BOOST_TEST(toml::detail::is_container<std::forward_list<dummy_type>>::value);
+    BOOST_TEST(toml::detail::is_container<std::deque<dummy_type>>::value);
+    BOOST_TEST(toml::detail::is_container<std::vector<dummy_type>>::value);
+    BOOST_TEST(toml::detail::is_container<std_array_type>::value);
+    BOOST_TEST(toml::detail::is_container<std::set<dummy_type>>::value);
+    BOOST_TEST(toml::detail::is_container<std::unordered_set<std::string>>::value);
+    BOOST_TEST(toml::detail::is_container<dummy_container<dummy_type>>::value);
 
-    BOOST_CHECK(!toml::detail::is_container<std_map_type>::value);
-    BOOST_CHECK(!toml::detail::is_container<std_unordered_map_type>::value);
+    BOOST_TEST(!toml::detail::is_container<std_map_type>::value);
+    BOOST_TEST(!toml::detail::is_container<std_unordered_map_type>::value);
 
-    BOOST_CHECK(toml::detail::is_map<std_map_type>::value);
-    BOOST_CHECK(toml::detail::is_map<std_unordered_map_type>::value);
+    BOOST_TEST(toml::detail::is_map<std_map_type>::value);
+    BOOST_TEST(toml::detail::is_map<std_unordered_map_type>::value);
 }

tests/test_utility.cpp

@@ -1,82 +1,45 @@
-#define BOOST_TEST_MODULE "test_acceptor"
-#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
-#include <boost/test/unit_test.hpp>
-#else
-#define BOOST_TEST_NO_LIB
-#include <boost/test/included/unit_test.hpp>
-#endif
 #include <toml/utility.hpp>
-#include <vector>
-#include <array>
 
-BOOST_AUTO_TEST_CASE(test_resize)
+#include "unit_test.hpp"
+
+#include <array>
+#include <vector>
+
+BOOST_AUTO_TEST_CASE(test_try_reserve)
 {
     {
-        typedef std::vector<int>  resizable_type;
-        typedef std::array<int,1> non_resizable_type;
-        BOOST_CHECK(toml::detail::has_resize_method<resizable_type>::value);
-        BOOST_CHECK(!toml::detail::has_resize_method<non_resizable_type>::value);
+        // since BOOST_TEST is a macro, it cannot handle commas correctly.
+        // When toml::detail::has_reserve_method<std::array<int, 1>>::value
+        // is passed to a macro, C preprocessor considers
+        // toml::detail::has_reserve_method<std::array<int as the first argument
+        // and 1>>::value as the second argument. We need an alias to avoid
+        // this problem.
+        using reservable_type    = std::vector<int>  ;
+        using nonreservable_type = std::array<int, 1>;
+        BOOST_TEST( toml::detail::has_reserve_method<reservable_type   >::value);
+        BOOST_TEST(!toml::detail::has_reserve_method<nonreservable_type>::value);
     }
-
     {
-        bool thrown = false;
         std::vector<int> v;
-        try
-        {
-            toml::resize(v, 10);
-        }
-        catch(std::exception& ex)
-        {
-            thrown = true;
-        }
-        BOOST_CHECK(!thrown);
-        BOOST_CHECK_EQUAL(v.size(), 10u);
-    }
-
-    {
-        bool thrown = false;
-        std::array<int, 15> a;
-        try
-        {
-            toml::resize(a, 10);
-        }
-        catch(std::exception& ex)
-        {
-            thrown = true;
-        }
-        BOOST_CHECK(!thrown);
-        BOOST_CHECK_EQUAL(a.size(), 15u);
-    }
-
-    {
-        bool thrown = false;
-        std::array<int, 15> a;
-        try
-        {
-            toml::resize(a, 20);
-        }
-        catch(std::exception& ex)
-        {
-            thrown = true;
-        }
-        BOOST_CHECK(thrown);
+        toml::try_reserve(v, 100);
+        BOOST_TEST(v.capacity() == 100u);
     }
 }
 
 BOOST_AUTO_TEST_CASE(test_concat_to_string)
 {
     const std::string cat = toml::concat_to_string("foo", "bar", 42);
-    BOOST_CHECK(cat == "foobar42");
+    BOOST_TEST(cat == "foobar42");
 }
 
 BOOST_AUTO_TEST_CASE(test_from_string)
 {
     {
         const std::string str("123");
-        BOOST_CHECK_EQUAL(toml::from_string<int>(str, 0), 123);
+        BOOST_TEST(toml::from_string<int>(str, 0) == 123);
     }
     {
         const std::string str("01");
-        BOOST_CHECK_EQUAL(toml::from_string<int>(str, 0), 1);
+        BOOST_TEST(toml::from_string<int>(str, 0) == 1);
     }
 }

tests/test_windows.cpp

@@ -0,0 +1,12 @@
+#include <windows.h>
+#include <toml.hpp>
+#include <iostream>
+
+int main()
+{
+    using namespace toml::literals::toml_literals;
+    const auto data = R"(windows = "defines min and max as a macro")"_toml;
+
+    std::cout << toml::find<std::string>(data, "windows") << std::endl;
+    return 0;
+}

tests/unit_test.hpp

@@ -0,0 +1,23 @@
+#ifndef BOOST_TEST_MODULE
+#    error "Please #define BOOST_TEST_MODULE before you #include <unit_test.hpp>"
+#endif
+
+#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
+#    include <boost/test/unit_test.hpp>
+#else
+#    include <boost/test/included/unit_test.hpp>
+#endif
+
+#include <cstdlib>
+#include <string>
+
+static inline auto testinput(const std::string& basename) -> std::string
+{
+    const auto this_or_that = [](const char *const s, const char *const t) { return s ? s : t; };
+    std::string directory = this_or_that(std::getenv("TOMLDIR"), "toml");
+    if (!directory.empty() && directory.back() != '/')
+    {
+        directory.push_back('/');
+    }
+    return directory.append("tests/").append(basename);
+}

toml.hpp

@@ -25,17 +25,14 @@
 #ifndef TOML_FOR_MODERN_CPP
 #define TOML_FOR_MODERN_CPP
 
-#ifndef __cplusplus
-#    error "__cplusplus is not defined"
-#endif
-
-#if __cplusplus < 201103L && _MSC_VER < 1900
-#    error "toml11 requires C++11 or later."
-#endif
+#define TOML11_VERSION_MAJOR 3
+#define TOML11_VERSION_MINOR 8
+#define TOML11_VERSION_PATCH 1
 
 #include "toml/parser.hpp"
-#include "toml/to_toml.hpp"
-#include "toml/from_toml.hpp"
+#include "toml/literal.hpp"
+#include "toml/serializer.hpp"
 #include "toml/get.hpp"
+#include "toml/macros.hpp"
 
 #endif// TOML_FOR_MODERN_CPP

toml/color.hpp

@@ -0,0 +1,109 @@
+#ifndef TOML11_COLOR_HPP
+#define TOML11_COLOR_HPP
+#include <cstdint>
+#include <ostream>
+
+#ifdef TOML11_COLORIZE_ERROR_MESSAGE
+#define TOML11_ERROR_MESSAGE_COLORIZED true
+#else
+#define TOML11_ERROR_MESSAGE_COLORIZED false
+#endif
+
+namespace toml
+{
+
+// put ANSI escape sequence to ostream
+namespace color_ansi
+{
+namespace detail
+{
+
+inline int colorize_index()
+{
+    static const int index = std::ios_base::xalloc();
+    return index;
+}
+
+// Control color mode globally
+class color_mode
+{
+  public:
+    inline void enable()
+    {
+        should_color_ = true;
+    }
+    inline void disable()
+    {
+        should_color_ = false;
+    }
+
+    inline bool should_color() const
+    {
+        return should_color_;
+    }
+
+    static color_mode& status()
+    {
+        static color_mode status_;
+        return status_;
+    }
+
+  private:
+    bool should_color_ = false;
+};
+
+} // detail
+
+inline std::ostream& colorize(std::ostream& os)
+{
+    // by default, it is zero.
+    os.iword(detail::colorize_index()) = 1;
+    return os;
+}
+inline std::ostream& nocolorize(std::ostream& os)
+{
+    os.iword(detail::colorize_index()) = 0;
+    return os;
+}
+inline std::ostream& reset  (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[00m";} return os;}
+inline std::ostream& bold   (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[01m";} return os;}
+inline std::ostream& grey   (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[30m";} return os;}
+inline std::ostream& red    (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[31m";} return os;}
+inline std::ostream& green  (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[32m";} return os;}
+inline std::ostream& yellow (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[33m";} return os;}
+inline std::ostream& blue   (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[34m";} return os;}
+inline std::ostream& magenta(std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[35m";} return os;}
+inline std::ostream& cyan   (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[36m";} return os;}
+inline std::ostream& white  (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[37m";} return os;}
+
+inline void enable()
+{
+    return detail::color_mode::status().enable();
+}
+inline void disable()
+{
+    return detail::color_mode::status().disable();
+}
+
+inline bool should_color()
+{
+    return detail::color_mode::status().should_color();
+}
+
+} // color_ansi
+
+// ANSI escape sequence is the only and default colorization method currently
+namespace color = color_ansi;
+
+} // toml
+#endif// TOML11_COLOR_HPP

toml/combinator.hpp

@@ -2,15 +2,20 @@
 // Distributed under the MIT License.
 #ifndef TOML11_COMBINATOR_HPP
 #define TOML11_COMBINATOR_HPP
-#include "traits.hpp"
-#include "result.hpp"
-#include "utility.hpp"
-#include "region.hpp"
-#include <type_traits>
+#include <cassert>
+#include <cctype>
+#include <cstdio>
+
+#include <array>
+#include <iomanip>
 #include <iterator>
 #include <limits>
-#include <iomanip>
-#include <cctype>
+#include <type_traits>
+
+#include "region.hpp"
+#include "result.hpp"
+#include "traits.hpp"
+#include "utility.hpp"
 
 // they scans characters and returns region if it matches to the condition.
 // when they fail, it does not change the location.
@@ -24,7 +29,7 @@ namespace detail
 // to output character as an error message.
 inline std::string show_char(const char c)
 {
-    // It supress an error that occurs only in Debug mode of MSVC++ on Windows.
+    // It suppresses an error that occurs only in Debug mode of MSVC++ on Windows.
     // I'm not completely sure but they check the value of char to be in the
     // range [0, 256) and some of the COMPLETELY VALID utf-8 character sometimes
     // has negative value (if char has sign). So here it re-interprets c as
@@ -38,10 +43,13 @@ inline std::string show_char(const char c)
     }
     else
     {
-        std::ostringstream oss;
-        oss << std::hex << std::setfill('0') << std::setw(2) << "0x"
-            << static_cast<int>(c);
-        return oss.str();
+        std::array<char, 5> buf;
+        buf.fill('\0');
+        const auto r = std::snprintf(
+                buf.data(), buf.size(), "0x%02x", static_cast<int>(c) & 0xFF);
+        (void) r; // Unused variable warning
+        assert(r == static_cast<int>(buf.size()) - 1);
+        return std::string(buf.data());
     }
 }
 
@@ -50,27 +58,21 @@ struct character
 {
     static constexpr char target = C;
 
-    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region, none_t>
+    invoke(location& loc)
     {
-        static_assert(std::is_same<char, typename Cont::value_type>::value,
-                      "internal error: container::value_type should be `char`.");
-
-        if(loc.iter() == loc.end()) {return err("not sufficient characters");}
+        if(loc.iter() == loc.end()) {return none();}
         const auto first = loc.iter();
 
         const char c = *(loc.iter());
         if(c != target)
         {
-            return err(concat_to_string("expected '", show_char(target),
-                                        "' but got '", show_char(c), "'."));
+            return none();
         }
-        ++(loc.iter()); // update location
+        loc.advance(); // update location
 
-        return ok(region<Cont>(loc, first, loc.iter()));
+        return ok(region(loc, first, loc.iter()));
     }
-
-    static std::string pattern() {return show_char(target);}
 };
 template<char C>
 constexpr char character<C>::target;
@@ -85,30 +87,20 @@ struct in_range
     static constexpr char upper = Up;
     static constexpr char lower = Low;
 
-    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region, none_t>
+    invoke(location& loc)
     {
-        static_assert(std::is_same<char, typename Cont::value_type>::value,
-                      "internal error: container::value_type should be `char`.");
-
-        if(loc.iter() == loc.end()) {return err("not sufficient characters");}
+        if(loc.iter() == loc.end()) {return none();}
         const auto first = loc.iter();
 
         const char c = *(loc.iter());
         if(c < lower || upper < c)
         {
-            return err(concat_to_string("expected character in range "
-                "[", show_char(lower), ", ", show_char(upper), "] but got ",
-                "'", show_char(c), "'."));
+            return none();
         }
 
-        ++(loc.iter());
-        return ok(region<Cont>(loc, first, loc.iter()));
-    }
-
-    static std::string pattern()
-    {
-        return concat_to_string("[",show_char(lower),"-",show_char(upper),"]");
+        loc.advance();
+        return ok(region(loc, first, loc.iter()));
     }
 };
 template<char L, char U> constexpr char in_range<L, U>::upper;
@@ -119,30 +111,20 @@ template<char L, char U> constexpr char in_range<L, U>::lower;
 template<typename Combinator>
 struct exclude
 {
-    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region, none_t>
+    invoke(location& loc)
     {
-        static_assert(std::is_same<char, typename Cont::value_type>::value,
-                      "internal error: container::value_type should be `char`.");
-
-        if(loc.iter() == loc.end()) {return err("not sufficient characters");}
+        if(loc.iter() == loc.end()) {return none();}
         auto first = loc.iter();
 
         auto rslt = Combinator::invoke(loc);
         if(rslt.is_ok())
         {
-            loc.iter() = first; // rollback
-            return err(concat_to_string(
-                "invalid pattern (", Combinator::pattern(), ") appeared ",
-                rslt.unwrap().str()));
+            loc.reset(first);
+            return none();
         }
-        loc.iter() = std::next(first);
-        return ok(region<Cont>(loc, first, loc.iter()));
-    }
-
-    static std::string pattern()
-    {
-        return concat_to_string("^(", Combinator::pattern(), ')');
+        loc.reset(std::next(first)); // XXX maybe loc.advance() is okay but...
+        return ok(region(loc, first, loc.iter()));
     }
 };
 
@@ -150,23 +132,15 @@ struct exclude
 template<typename Combinator>
 struct maybe
 {
-    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region, none_t>
+    invoke(location& loc)
     {
-        static_assert(std::is_same<char, typename Cont::value_type>::value,
-                      "internal error: container::value_type should be `char`.");
-
         const auto rslt = Combinator::invoke(loc);
         if(rslt.is_ok())
         {
             return rslt;
         }
-        return ok(region<Cont>(loc));
-    }
-
-    static std::string pattern()
-    {
-        return concat_to_string('(', Combinator::pattern(), ")?");
+        return ok(region(loc));
     }
 };
 
@@ -176,61 +150,52 @@ struct sequence;
 template<typename Head, typename ... Tail>
 struct sequence<Head, Tail...>
 {
-    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region, none_t>
+    invoke(location& loc)
     {
-        static_assert(std::is_same<char, typename Cont::value_type>::value,
-                      "internal error: container::value_type should be `char`.");
-
         const auto first = loc.iter();
-        const auto rslt = Head::invoke(loc);
+        auto rslt = Head::invoke(loc);
         if(rslt.is_err())
         {
-            loc.iter() = first;
-            return err(rslt.unwrap_err());
+            loc.reset(first);
+            return none();
         }
         return sequence<Tail...>::invoke(loc, std::move(rslt.unwrap()), first);
     }
 
     // called from the above function only, recursively.
-    template<typename Cont, typename Iterator>
-    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, region<Cont> reg, Iterator first)
+    template<typename Iterator>
+    static result<region, none_t>
+    invoke(location& loc, region reg, Iterator first)
     {
         const auto rslt = Head::invoke(loc);
         if(rslt.is_err())
         {
-            loc.iter() = first;
-            return err(rslt.unwrap_err());
+            loc.reset(first);
+            return none();
         }
         reg += rslt.unwrap(); // concat regions
         return sequence<Tail...>::invoke(loc, std::move(reg), first);
     }
-
-    static std::string pattern()
-    {
-        return concat_to_string(Head::pattern(), sequence<Tail...>::pattern());
-    }
 };
 
 template<typename Head>
 struct sequence<Head>
 {
     // would be called from sequence<T ...>::invoke only.
-    template<typename Cont, typename Iterator>
-    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, region<Cont> reg, Iterator first)
+    template<typename Iterator>
+    static result<region, none_t>
+    invoke(location& loc, region reg, Iterator first)
     {
         const auto rslt = Head::invoke(loc);
         if(rslt.is_err())
         {
-            loc.iter() = first;
-            return err(rslt.unwrap_err());
+            loc.reset(first);
+            return none();
         }
         reg += rslt.unwrap(); // concat regions
         return ok(reg);
     }
-    static std::string pattern() {return Head::pattern();}
 };
 
 template<typename ... Ts>
@@ -239,36 +204,22 @@ struct either;
 template<typename Head, typename ... Tail>
 struct either<Head, Tail...>
 {
-    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region, none_t>
+    invoke(location& loc)
     {
-        static_assert(std::is_same<char, typename Cont::value_type>::value,
-                      "internal error: container::value_type should be `char`.");
-
         const auto rslt = Head::invoke(loc);
         if(rslt.is_ok()) {return rslt;}
         return either<Tail...>::invoke(loc);
     }
-
-    static std::string pattern()
-    {
-        return concat_to_string('(', Head::pattern(), ")|", either<Tail...>::pattern());
-    }
 };
 template<typename Head>
 struct either<Head>
 {
-    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region, none_t>
+    invoke(location& loc)
     {
-        static_assert(std::is_same<char, typename Cont::value_type>::value,
-                      "internal error: container::value_type should be `char`.");
         return Head::invoke(loc);
     }
-    static std::string pattern()
-    {
-        return concat_to_string('(', Head::pattern(), ')');
-    }
 };
 
 template<typename T, typename N>
@@ -281,36 +232,32 @@ struct unlimited{};
 template<typename T, std::size_t N>
 struct repeat<T, exactly<N>>
 {
-    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region, none_t>
+    invoke(location& loc)
     {
-        region<Cont> retval(loc);
+        region retval(loc);
         const auto first = loc.iter();
         for(std::size_t i=0; i<N; ++i)
         {
             auto rslt = T::invoke(loc);
             if(rslt.is_err())
             {
-                loc.iter() = first;
-                return err(rslt.unwrap_err());
+                loc.reset(first);
+                return none();
             }
             retval += rslt.unwrap();
         }
         return ok(std::move(retval));
     }
-    static std::string pattern()
-    {
-        return concat_to_string('(', T::pattern(), "){", N, '}');
-    }
 };
 
 template<typename T, std::size_t N>
 struct repeat<T, at_least<N>>
 {
-    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region, none_t>
+    invoke(location& loc)
     {
-        region<Cont> retval(loc);
+        region retval(loc);
 
         const auto first = loc.iter();
         for(std::size_t i=0; i<N; ++i)
@@ -318,8 +265,8 @@ struct repeat<T, at_least<N>>
             auto rslt = T::invoke(loc);
             if(rslt.is_err())
             {
-                loc.iter() = first;
-                return err(rslt.unwrap_err());
+                loc.reset(first);
+                return none();
             }
             retval += rslt.unwrap();
         }
@@ -333,19 +280,15 @@ struct repeat<T, at_least<N>>
             retval += rslt.unwrap();
         }
     }
-    static std::string pattern()
-    {
-        return concat_to_string('(',T::pattern(), "){", N, ",}");
-    }
 };
 
 template<typename T>
 struct repeat<T, unlimited>
 {
-    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region, none_t>
+    invoke(location& loc)
     {
-        region<Cont> retval(loc);
+        region retval(loc);
         while(true)
         {
             auto rslt = T::invoke(loc);
@@ -356,7 +299,6 @@ struct repeat<T, unlimited>
             retval += rslt.unwrap();
         }
     }
-    static std::string pattern() {return concat_to_string('(', T::pattern(), ")*");}
 };
 
 } // detail

toml/comments.hpp

@@ -0,0 +1,484 @@
+//     Copyright Toru Niina 2019.
+// Distributed under the MIT License.
+#ifndef TOML11_COMMENTS_HPP
+#define TOML11_COMMENTS_HPP
+#include <initializer_list>
+#include <iterator>
+#include <stdexcept>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+#ifdef TOML11_PRESERVE_COMMENTS_BY_DEFAULT
+#  define TOML11_DEFAULT_COMMENT_STRATEGY ::toml::preserve_comments
+#else
+#  define TOML11_DEFAULT_COMMENT_STRATEGY ::toml::discard_comments
+#endif
+
+// This file provides mainly two classes, `preserve_comments` and `discard_comments`.
+// Those two are a container that have the same interface as `std::vector<std::string>`
+// but bahaves in the opposite way. `preserve_comments` is just the same as
+// `std::vector<std::string>` and each `std::string` corresponds to a comment line.
+// Conversely, `discard_comments` discards all the strings and ignores everything
+// assigned in it. `discard_comments` is always empty and you will encounter an
+// error whenever you access to the element.
+namespace toml
+{
+struct discard_comments; // forward decl
+
+// use it in the following way
+//
+// const toml::basic_value<toml::preserve_comments> data =
+//     toml::parse<toml::preserve_comments>("example.toml");
+//
+// the interface is almost the same as std::vector<std::string>.
+struct preserve_comments
+{
+    // `container_type` is not provided in discard_comments.
+    // do not use this inner-type in a generic code.
+    using container_type         = std::vector<std::string>;
+
+    using size_type              = container_type::size_type;
+    using difference_type        = container_type::difference_type;
+    using value_type             = container_type::value_type;
+    using reference              = container_type::reference;
+    using const_reference        = container_type::const_reference;
+    using pointer                = container_type::pointer;
+    using const_pointer          = container_type::const_pointer;
+    using iterator               = container_type::iterator;
+    using const_iterator         = container_type::const_iterator;
+    using reverse_iterator       = container_type::reverse_iterator;
+    using const_reverse_iterator = container_type::const_reverse_iterator;
+
+    preserve_comments()  = default;
+    ~preserve_comments() = default;
+    preserve_comments(preserve_comments const&) = default;
+    preserve_comments(preserve_comments &&)     = default;
+    preserve_comments& operator=(preserve_comments const&) = default;
+    preserve_comments& operator=(preserve_comments &&)     = default;
+
+    explicit preserve_comments(const std::vector<std::string>& c): comments(c){}
+    explicit preserve_comments(std::vector<std::string>&& c)
+        : comments(std::move(c))
+    {}
+    preserve_comments& operator=(const std::vector<std::string>& c)
+    {
+        comments = c;
+        return *this;
+    }
+    preserve_comments& operator=(std::vector<std::string>&& c)
+    {
+        comments = std::move(c);
+        return *this;
+    }
+
+    explicit preserve_comments(const discard_comments&) {}
+
+    explicit preserve_comments(size_type n): comments(n) {}
+    preserve_comments(size_type n, const std::string& x): comments(n, x) {}
+    preserve_comments(std::initializer_list<std::string> x): comments(x) {}
+    template<typename InputIterator>
+    preserve_comments(InputIterator first, InputIterator last)
+        : comments(first, last)
+    {}
+
+    template<typename InputIterator>
+    void assign(InputIterator first, InputIterator last) {comments.assign(first, last);}
+    void assign(std::initializer_list<std::string> ini)  {comments.assign(ini);}
+    void assign(size_type n, const std::string& val)     {comments.assign(n, val);}
+
+    // Related to the issue #97.
+    //
+    // It is known that `std::vector::insert` and `std::vector::erase` in
+    // the standard library implementation included in GCC 4.8.5 takes
+    // `std::vector::iterator` instead of `std::vector::const_iterator`.
+    // Because of the const-correctness, we cannot convert a `const_iterator` to
+    // an `iterator`. It causes compilation error in GCC 4.8.5.
+#if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__) && !defined(__clang__)
+#  if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) <= 40805
+#    define TOML11_WORKAROUND_GCC_4_8_X_STANDARD_LIBRARY_IMPLEMENTATION
+#  endif
+#endif
+
+#ifdef TOML11_WORKAROUND_GCC_4_8_X_STANDARD_LIBRARY_IMPLEMENTATION
+    iterator insert(iterator p, const std::string& x)
+    {
+        return comments.insert(p, x);
+    }
+    iterator insert(iterator p, std::string&&      x)
+    {
+        return comments.insert(p, std::move(x));
+    }
+    void insert(iterator p, size_type n, const std::string& x)
+    {
+        return comments.insert(p, n, x);
+    }
+    template<typename InputIterator>
+    void insert(iterator p, InputIterator first, InputIterator last)
+    {
+        return comments.insert(p, first, last);
+    }
+    void insert(iterator p, std::initializer_list<std::string> ini)
+    {
+        return comments.insert(p, ini);
+    }
+
+    template<typename ... Ts>
+    iterator emplace(iterator p, Ts&& ... args)
+    {
+        return comments.emplace(p, std::forward<Ts>(args)...);
+    }
+
+    iterator erase(iterator pos) {return comments.erase(pos);}
+    iterator erase(iterator first, iterator last)
+    {
+        return comments.erase(first, last);
+    }
+#else
+    iterator insert(const_iterator p, const std::string& x)
+    {
+        return comments.insert(p, x);
+    }
+    iterator insert(const_iterator p, std::string&&      x)
+    {
+        return comments.insert(p, std::move(x));
+    }
+    iterator insert(const_iterator p, size_type n, const std::string& x)
+    {
+        return comments.insert(p, n, x);
+    }
+    template<typename InputIterator>
+    iterator insert(const_iterator p, InputIterator first, InputIterator last)
+    {
+        return comments.insert(p, first, last);
+    }
+    iterator insert(const_iterator p, std::initializer_list<std::string> ini)
+    {
+        return comments.insert(p, ini);
+    }
+
+    template<typename ... Ts>
+    iterator emplace(const_iterator p, Ts&& ... args)
+    {
+        return comments.emplace(p, std::forward<Ts>(args)...);
+    }
+
+    iterator erase(const_iterator pos) {return comments.erase(pos);}
+    iterator erase(const_iterator first, const_iterator last)
+    {
+        return comments.erase(first, last);
+    }
+#endif
+
+    void swap(preserve_comments& other) {comments.swap(other.comments);}
+
+    void push_back(const std::string& v) {comments.push_back(v);}
+    void push_back(std::string&&      v) {comments.push_back(std::move(v));}
+    void pop_back()                      {comments.pop_back();}
+
+    template<typename ... Ts>
+    void emplace_back(Ts&& ... args) {comments.emplace_back(std::forward<Ts>(args)...);}
+
+    void clear() {comments.clear();}
+
+    size_type size()     const noexcept {return comments.size();}
+    size_type max_size() const noexcept {return comments.max_size();}
+    size_type capacity() const noexcept {return comments.capacity();}
+    bool      empty()    const noexcept {return comments.empty();}
+
+    void reserve(size_type n)                      {comments.reserve(n);}
+    void resize(size_type n)                       {comments.resize(n);}
+    void resize(size_type n, const std::string& c) {comments.resize(n, c);}
+    void shrink_to_fit()                           {comments.shrink_to_fit();}
+
+    reference       operator[](const size_type n)       noexcept {return comments[n];}
+    const_reference operator[](const size_type n) const noexcept {return comments[n];}
+    reference       at(const size_type n)       {return comments.at(n);}
+    const_reference at(const size_type n) const {return comments.at(n);}
+    reference       front()       noexcept {return comments.front();}
+    const_reference front() const noexcept {return comments.front();}
+    reference       back()        noexcept {return comments.back();}
+    const_reference back()  const noexcept {return comments.back();}
+
+    pointer         data()        noexcept {return comments.data();}
+    const_pointer   data()  const noexcept {return comments.data();}
+
+    iterator       begin()        noexcept {return comments.begin();}
+    iterator       end()          noexcept {return comments.end();}
+    const_iterator begin()  const noexcept {return comments.begin();}
+    const_iterator end()    const noexcept {return comments.end();}
+    const_iterator cbegin() const noexcept {return comments.cbegin();}
+    const_iterator cend()   const noexcept {return comments.cend();}
+
+    reverse_iterator       rbegin()        noexcept {return comments.rbegin();}
+    reverse_iterator       rend()          noexcept {return comments.rend();}
+    const_reverse_iterator rbegin()  const noexcept {return comments.rbegin();}
+    const_reverse_iterator rend()    const noexcept {return comments.rend();}
+    const_reverse_iterator crbegin() const noexcept {return comments.crbegin();}
+    const_reverse_iterator crend()   const noexcept {return comments.crend();}
+
+    friend bool operator==(const preserve_comments&, const preserve_comments&);
+    friend bool operator!=(const preserve_comments&, const preserve_comments&);
+    friend bool operator< (const preserve_comments&, const preserve_comments&);
+    friend bool operator<=(const preserve_comments&, const preserve_comments&);
+    friend bool operator> (const preserve_comments&, const preserve_comments&);
+    friend bool operator>=(const preserve_comments&, const preserve_comments&);
+
+    friend void swap(preserve_comments&, std::vector<std::string>&);
+    friend void swap(std::vector<std::string>&, preserve_comments&);
+
+  private:
+
+    container_type comments;
+};
+
+inline bool operator==(const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments == rhs.comments;}
+inline bool operator!=(const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments != rhs.comments;}
+inline bool operator< (const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments <  rhs.comments;}
+inline bool operator<=(const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments <= rhs.comments;}
+inline bool operator> (const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments >  rhs.comments;}
+inline bool operator>=(const preserve_comments& lhs, const preserve_comments& rhs) {return lhs.comments >= rhs.comments;}
+
+inline void swap(preserve_comments& lhs, preserve_comments& rhs)
+{
+    lhs.swap(rhs);
+    return;
+}
+inline void swap(preserve_comments& lhs, std::vector<std::string>& rhs)
+{
+    lhs.comments.swap(rhs);
+    return;
+}
+inline void swap(std::vector<std::string>& lhs, preserve_comments& rhs)
+{
+    lhs.swap(rhs.comments);
+    return;
+}
+
+template<typename charT, typename traits>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const preserve_comments& com)
+{
+    for(const auto& c : com)
+    {
+        os << '#' << c << '\n';
+    }
+    return os;
+}
+
+namespace detail
+{
+
+// To provide the same interface with `preserve_comments`, `discard_comments`
+// should have an iterator. But it does not contain anything, so we need to
+// add an iterator that points nothing.
+//
+// It always points null, so DO NOT unwrap this iterator. It always crashes
+// your program.
+template<typename T, bool is_const>
+struct empty_iterator
+{
+    using value_type        = T;
+    using reference_type    = typename std::conditional<is_const, T const&, T&>::type;
+    using pointer_type      = typename std::conditional<is_const, T const*, T*>::type;
+    using difference_type   = std::ptrdiff_t;
+    using iterator_category = std::random_access_iterator_tag;
+
+    empty_iterator()  = default;
+    ~empty_iterator() = default;
+    empty_iterator(empty_iterator const&) = default;
+    empty_iterator(empty_iterator &&)     = default;
+    empty_iterator& operator=(empty_iterator const&) = default;
+    empty_iterator& operator=(empty_iterator &&)     = default;
+
+    // DO NOT call these operators.
+    reference_type operator*()  const noexcept {std::terminate();}
+    pointer_type   operator->() const noexcept {return nullptr;}
+    reference_type operator[](difference_type) const noexcept {return this->operator*();}
+
+    // These operators do nothing.
+    empty_iterator& operator++()    noexcept {return *this;}
+    empty_iterator  operator++(int) noexcept {return *this;}
+    empty_iterator& operator--()    noexcept {return *this;}
+    empty_iterator  operator--(int) noexcept {return *this;}
+
+    empty_iterator& operator+=(difference_type) noexcept {return *this;}
+    empty_iterator& operator-=(difference_type) noexcept {return *this;}
+
+    empty_iterator  operator+(difference_type) const noexcept {return *this;}
+    empty_iterator  operator-(difference_type) const noexcept {return *this;}
+};
+
+template<typename T, bool C>
+bool operator==(const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return true;}
+template<typename T, bool C>
+bool operator!=(const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return false;}
+template<typename T, bool C>
+bool operator< (const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return false;}
+template<typename T, bool C>
+bool operator<=(const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return true;}
+template<typename T, bool C>
+bool operator> (const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return false;}
+template<typename T, bool C>
+bool operator>=(const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return true;}
+
+template<typename T, bool C>
+typename empty_iterator<T, C>::difference_type
+operator-(const empty_iterator<T, C>&, const empty_iterator<T, C>&) noexcept {return 0;}
+
+template<typename T, bool C>
+empty_iterator<T, C>
+operator+(typename empty_iterator<T, C>::difference_type, const empty_iterator<T, C>& rhs) noexcept {return rhs;}
+template<typename T, bool C>
+empty_iterator<T, C>
+operator+(const empty_iterator<T, C>& lhs, typename empty_iterator<T, C>::difference_type) noexcept {return lhs;}
+
+} // detail
+
+// The default comment type. It discards all the comments. It requires only one
+// byte to contain, so the memory footprint is smaller than preserve_comments.
+//
+// It just ignores `push_back`, `insert`, `erase`, and any other modifications.
+// IT always returns size() == 0, the iterator taken by `begin()` is always the
+// same as that of `end()`, and accessing through `operator[]` or iterators
+// always causes a segmentation fault. DO NOT access to the element of this.
+//
+// Why this is chose as the default type is because the last version (2.x.y)
+// does not contain any comments in a value. To minimize the impact on the
+// efficiency, this is chosen as a default.
+//
+// To reduce the memory footprint, later we can try empty base optimization (EBO).
+struct discard_comments
+{
+    using size_type              = std::size_t;
+    using difference_type        = std::ptrdiff_t;
+    using value_type             = std::string;
+    using reference              = std::string&;
+    using const_reference        = std::string const&;
+    using pointer                = std::string*;
+    using const_pointer          = std::string const*;
+    using iterator               = detail::empty_iterator<std::string, false>;
+    using const_iterator         = detail::empty_iterator<std::string, true>;
+    using reverse_iterator       = detail::empty_iterator<std::string, false>;
+    using const_reverse_iterator = detail::empty_iterator<std::string, true>;
+
+    discard_comments() = default;
+    ~discard_comments() = default;
+    discard_comments(discard_comments const&) = default;
+    discard_comments(discard_comments &&)     = default;
+    discard_comments& operator=(discard_comments const&) = default;
+    discard_comments& operator=(discard_comments &&)     = default;
+
+    explicit discard_comments(const std::vector<std::string>&) noexcept {}
+    explicit discard_comments(std::vector<std::string>&&)      noexcept {}
+    discard_comments& operator=(const std::vector<std::string>&) noexcept {return *this;}
+    discard_comments& operator=(std::vector<std::string>&&)      noexcept {return *this;}
+
+    explicit discard_comments(const preserve_comments&)        noexcept {}
+
+    explicit discard_comments(size_type) noexcept {}
+    discard_comments(size_type, const std::string&) noexcept {}
+    discard_comments(std::initializer_list<std::string>) noexcept {}
+    template<typename InputIterator>
+    discard_comments(InputIterator, InputIterator) noexcept {}
+
+    template<typename InputIterator>
+    void assign(InputIterator, InputIterator)       noexcept {}
+    void assign(std::initializer_list<std::string>) noexcept {}
+    void assign(size_type, const std::string&)      noexcept {}
+
+    iterator insert(const_iterator, const std::string&)                 {return iterator{};}
+    iterator insert(const_iterator, std::string&&)                      {return iterator{};}
+    iterator insert(const_iterator, size_type, const std::string&)      {return iterator{};}
+    template<typename InputIterator>
+    iterator insert(const_iterator, InputIterator, InputIterator)       {return iterator{};}
+    iterator insert(const_iterator, std::initializer_list<std::string>) {return iterator{};}
+
+    template<typename ... Ts>
+    iterator emplace(const_iterator, Ts&& ...)     {return iterator{};}
+    iterator erase(const_iterator)                 {return iterator{};}
+    iterator erase(const_iterator, const_iterator) {return iterator{};}
+
+    void swap(discard_comments&) {return;}
+
+    void push_back(const std::string&) {return;}
+    void push_back(std::string&&     ) {return;}
+    void pop_back()                    {return;}
+
+    template<typename ... Ts>
+    void emplace_back(Ts&& ...) {return;}
+
+    void clear() {return;}
+
+    size_type size()     const noexcept {return 0;}
+    size_type max_size() const noexcept {return 0;}
+    size_type capacity() const noexcept {return 0;}
+    bool      empty()    const noexcept {return true;}
+
+    void reserve(size_type)                    {return;}
+    void resize(size_type)                     {return;}
+    void resize(size_type, const std::string&) {return;}
+    void shrink_to_fit()                       {return;}
+
+    // DO NOT access to the element of this container. This container is always
+    // empty, so accessing through operator[], front/back, data causes address
+    // error.
+
+    reference       operator[](const size_type)       noexcept {never_call("toml::discard_comment::operator[]");}
+    const_reference operator[](const size_type) const noexcept {never_call("toml::discard_comment::operator[]");}
+    reference       at(const size_type)       {throw std::out_of_range("toml::discard_comment is always empty.");}
+    const_reference at(const size_type) const {throw std::out_of_range("toml::discard_comment is always empty.");}
+    reference       front()       noexcept {never_call("toml::discard_comment::front");}
+    const_reference front() const noexcept {never_call("toml::discard_comment::front");}
+    reference       back()        noexcept {never_call("toml::discard_comment::back");}
+    const_reference back()  const noexcept {never_call("toml::discard_comment::back");}
+
+    pointer         data()        noexcept {return nullptr;}
+    const_pointer   data()  const noexcept {return nullptr;}
+
+    iterator       begin()        noexcept {return iterator{};}
+    iterator       end()          noexcept {return iterator{};}
+    const_iterator begin()  const noexcept {return const_iterator{};}
+    const_iterator end()    const noexcept {return const_iterator{};}
+    const_iterator cbegin() const noexcept {return const_iterator{};}
+    const_iterator cend()   const noexcept {return const_iterator{};}
+
+    reverse_iterator       rbegin()        noexcept {return iterator{};}
+    reverse_iterator       rend()          noexcept {return iterator{};}
+    const_reverse_iterator rbegin()  const noexcept {return const_iterator{};}
+    const_reverse_iterator rend()    const noexcept {return const_iterator{};}
+    const_reverse_iterator crbegin() const noexcept {return const_iterator{};}
+    const_reverse_iterator crend()   const noexcept {return const_iterator{};}
+
+  private:
+
+    [[noreturn]] static void never_call(const char *const this_function)
+    {
+#ifdef __has_builtin
+#  if __has_builtin(__builtin_unreachable)
+        __builtin_unreachable();
+#  endif
+#endif
+        throw std::logic_error{this_function};
+    }
+};
+
+inline bool operator==(const discard_comments&, const discard_comments&) noexcept {return true;}
+inline bool operator!=(const discard_comments&, const discard_comments&) noexcept {return false;}
+inline bool operator< (const discard_comments&, const discard_comments&) noexcept {return false;}
+inline bool operator<=(const discard_comments&, const discard_comments&) noexcept {return true;}
+inline bool operator> (const discard_comments&, const discard_comments&) noexcept {return false;}
+inline bool operator>=(const discard_comments&, const discard_comments&) noexcept {return true;}
+
+inline void swap(const discard_comments&, const discard_comments&) noexcept {return;}
+
+template<typename charT, typename traits>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const discard_comments&)
+{
+    return os;
+}
+
+} // toml11
+#endif// TOML11_COMMENTS_HPP

toml/datetime.hpp

@@ -1,20 +1,73 @@
 //     Copyright Toru Niina 2017.
 // Distributed under the MIT License.
-#ifndef TOML11_DATETIME
-#define TOML11_DATETIME
-#include <chrono>
-#include <tuple>
-#include <array>
-#include <ostream>
-#include <iomanip>
+#ifndef TOML11_DATETIME_HPP
+#define TOML11_DATETIME_HPP
 #include <cstdint>
 #include <cstdlib>
 #include <ctime>
 
+#include <array>
+#include <chrono>
+#include <iomanip>
+#include <ostream>
+#include <tuple>
+
 namespace toml
 {
 
-enum class month_t : std::int8_t
+// To avoid non-threadsafe std::localtime. In C11 (not C++11!), localtime_s is
+// provided in the absolutely same purpose, but C++11 is actually not compatible
+// with C11. We need to dispatch the function depending on the OS.
+namespace detail
+{
+// TODO: find more sophisticated way to handle this
+#if defined(_MSC_VER)
+inline std::tm localtime_s(const std::time_t* src)
+{
+    std::tm dst;
+    const auto result = ::localtime_s(&dst, src);
+    if (result) { throw std::runtime_error("localtime_s failed."); }
+    return dst;
+}
+inline std::tm gmtime_s(const std::time_t* src)
+{
+    std::tm dst;
+    const auto result = ::gmtime_s(&dst, src);
+    if (result) { throw std::runtime_error("gmtime_s failed."); }
+    return dst;
+}
+#elif (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 1) || defined(_XOPEN_SOURCE) || defined(_BSD_SOURCE) || defined(_SVID_SOURCE) || defined(_POSIX_SOURCE)
+inline std::tm localtime_s(const std::time_t* src)
+{
+    std::tm dst;
+    const auto result = ::localtime_r(src, &dst);
+    if (!result) { throw std::runtime_error("localtime_r failed."); }
+    return dst;
+}
+inline std::tm gmtime_s(const std::time_t* src)
+{
+    std::tm dst;
+    const auto result = ::gmtime_r(src, &dst);
+    if (!result) { throw std::runtime_error("gmtime_r failed."); }
+    return dst;
+}
+#else // fallback. not threadsafe
+inline std::tm localtime_s(const std::time_t* src)
+{
+    const auto result = std::localtime(src);
+    if (!result) { throw std::runtime_error("localtime failed."); }
+    return *result;
+}
+inline std::tm gmtime_s(const std::time_t* src)
+{
+    const auto result = std::gmtime(src);
+    if (!result) { throw std::runtime_error("gmtime failed."); }
+    return *result;
+}
+#endif
+} // detail
+
+enum class month_t : std::uint8_t
 {
     Jan =  0,
     Feb =  1,
@@ -32,9 +85,9 @@ enum class month_t : std::int8_t
 
 struct local_date
 {
-    std::int16_t year;   // A.D. (like, 2018)
-    std::uint8_t month;  // [0, 11]
-    std::uint8_t day;    // [1, 31]
+    std::int16_t year{};   // A.D. (like, 2018)
+    std::uint8_t month{};  // [0, 11]
+    std::uint8_t day{};    // [1, 31]
 
     local_date(int y, month_t m, int d)
         : year (static_cast<std::int16_t>(y)),
@@ -50,10 +103,8 @@ struct local_date
 
     explicit local_date(const std::chrono::system_clock::time_point& tp)
     {
-        const auto t = std::chrono::system_clock::to_time_t(tp);
-        const auto tmp = std::localtime(&t); //XXX: not threadsafe!
-        assert(tmp); // if std::localtime fails, tmp is nullptr
-        const std::tm time = *tmp;
+        const auto t    = std::chrono::system_clock::to_time_t(tp);
+        const auto time = detail::localtime_s(&t);
         *this = local_date(time);
     }
 
@@ -68,9 +119,9 @@ struct local_date
         t.tm_sec   = 0;
         t.tm_min   = 0;
         t.tm_hour  = 0;
-        t.tm_mday  = this->day;
-        t.tm_mon   = this->month;
-        t.tm_year  = this->year - 1900;
+        t.tm_mday  = static_cast<int>(this->day);
+        t.tm_mon   = static_cast<int>(this->month);
+        t.tm_year  = static_cast<int>(this->year) - 1900;
         t.tm_wday  = 0; // the value will be ignored
         t.tm_yday  = 0; // the value will be ignored
         t.tm_isdst = -1;
@@ -122,20 +173,20 @@ template<typename charT, typename traits>
 std::basic_ostream<charT, traits>&
 operator<<(std::basic_ostream<charT, traits>& os, const local_date& date)
 {
-    os << std::setfill('0') << std::setw(4) << static_cast<int>(date.year     ) << '-';
-    os << std::setfill('0') << std::setw(2) << static_cast<int>(date.month + 1) << '-';
-    os << std::setfill('0') << std::setw(2) << static_cast<int>(date.day      );
+    os << std::setfill('0') << std::setw(4) << static_cast<int>(date.year )     << '-';
+    os << std::setfill('0') << std::setw(2) << static_cast<int>(date.month) + 1 << '-';
+    os << std::setfill('0') << std::setw(2) << static_cast<int>(date.day  )    ;
     return os;
 }
 
 struct local_time
 {
-    std::uint8_t  hour;        // [0, 23]
-    std::uint8_t  minute;      // [0, 59]
-    std::uint8_t  second;      // [0, 60]
-    std::uint16_t millisecond; // [0, 999]
-    std::uint16_t microsecond; // [0, 999]
-    std::uint16_t nanosecond;  // [0, 999]
+    std::uint8_t  hour{};        // [0, 23]
+    std::uint8_t  minute{};      // [0, 59]
+    std::uint8_t  second{};      // [0, 60]
+    std::uint16_t millisecond{}; // [0, 999]
+    std::uint16_t microsecond{}; // [0, 999]
+    std::uint16_t nanosecond{};  // [0, 999]
 
     local_time(int h, int m, int s,
                int ms = 0, int us = 0, int ns = 0)
@@ -158,22 +209,22 @@ struct local_time
     explicit local_time(const std::chrono::duration<Rep, Period>& t)
     {
         const auto h = std::chrono::duration_cast<std::chrono::hours>(t);
-        this->hour = h.count();
+        this->hour = static_cast<std::uint8_t>(h.count());
         const auto t2 = t - h;
         const auto m = std::chrono::duration_cast<std::chrono::minutes>(t2);
-        this->minute = m.count();
+        this->minute = static_cast<std::uint8_t>(m.count());
         const auto t3 = t2 - m;
         const auto s = std::chrono::duration_cast<std::chrono::seconds>(t3);
-        this->second = s.count();
+        this->second = static_cast<std::uint8_t>(s.count());
         const auto t4 = t3 - s;
         const auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(t4);
-        this->millisecond = ms.count();
+        this->millisecond = static_cast<std::uint16_t>(ms.count());
         const auto t5 = t4 - ms;
         const auto us = std::chrono::duration_cast<std::chrono::microseconds>(t5);
-        this->microsecond = us.count();
+        this->microsecond = static_cast<std::uint16_t>(us.count());
         const auto t6 = t5 - us;
         const auto ns = std::chrono::duration_cast<std::chrono::nanoseconds>(t6);
-        this->nanosecond = ns.count();
+        this->nanosecond = static_cast<std::uint16_t>(ns.count());
     }
 
     operator std::chrono::nanoseconds() const
@@ -246,8 +297,8 @@ operator<<(std::basic_ostream<charT, traits>& os, const local_time& time)
 
 struct time_offset
 {
-    std::int8_t hour;   // [-12, 12]
-    std::int8_t minute; // [-59, 59]
+    std::int8_t hour{};   // [-12, 12]
+    std::int8_t minute{}; // [-59, 59]
 
     time_offset(int h, int m)
         : hour  (static_cast<std::int8_t>(h)),
@@ -304,24 +355,17 @@ operator<<(std::basic_ostream<charT, traits>& os, const time_offset& offset)
         os << 'Z';
         return os;
     }
-    if(static_cast<int>(offset.hour) * static_cast<int>(offset.minute) < 0)
-    {
-        const int min = static_cast<int>(offset.hour) * 60 + offset.minute;
-        if(min < 0){os << '-';} else {os << '+';}
-        os << std::setfill('0') << std::setw(2) << min / 60 << ':';
-        os << std::setfill('0') << std::setw(2) << min % 60;
-        return os;
-    }
-    if(offset.hour < 0){os << '-';} else {os << '+';}
-    os << std::setfill('0') << std::setw(2) << static_cast<int>(offset.hour) << ':';
-    os << std::setfill('0') << std::setw(2) << static_cast<int>(offset.minute);
+    int minute = static_cast<int>(offset.hour) * 60 + offset.minute;
+    if(minute < 0){os << '-'; minute = std::abs(minute);} else {os << '+';}
+    os << std::setfill('0') << std::setw(2) << minute / 60 << ':';
+    os << std::setfill('0') << std::setw(2) << minute % 60;
     return os;
 }
 
 struct local_datetime
 {
-    local_date date;
-    local_time time;
+    local_date date{};
+    local_time time{};
 
     local_datetime(local_date d, local_time t): date(d), time(t) {}
 
@@ -330,23 +374,21 @@ struct local_datetime
     explicit local_datetime(const std::chrono::system_clock::time_point& tp)
     {
         const auto t = std::chrono::system_clock::to_time_t(tp);
-        const auto tmp = std::localtime(&t); //XXX: not threadsafe!
-        assert(tmp); // if std::localtime fails, tmp is nullptr
+        std::tm ltime = detail::localtime_s(&t);
 
-        std::tm time = *tmp;
-        this->date = local_date(time);
-        this->time = local_time(time);
+        this->date = local_date(ltime);
+        this->time = local_time(ltime);
 
         // std::tm lacks subsecond information, so diff between tp and tm
         // can be used to get millisecond & microsecond information.
         const auto t_diff = tp -
-            std::chrono::system_clock::from_time_t(std::mktime(&time));
-        this->time.millisecond = std::chrono::duration_cast<
-            std::chrono::milliseconds>(t_diff).count();
-        this->time.microsecond = std::chrono::duration_cast<
-            std::chrono::microseconds>(t_diff).count();
-        this->time.nanosecond = std::chrono::duration_cast<
-            std::chrono::nanoseconds >(t_diff).count();
+            std::chrono::system_clock::from_time_t(std::mktime(&ltime));
+        this->time.millisecond = static_cast<std::uint16_t>(
+          std::chrono::duration_cast<std::chrono::milliseconds>(t_diff).count());
+        this->time.microsecond = static_cast<std::uint16_t>(
+          std::chrono::duration_cast<std::chrono::microseconds>(t_diff).count());
+        this->time.nanosecond = static_cast<std::uint16_t>(
+          std::chrono::duration_cast<std::chrono::nanoseconds >(t_diff).count());
     }
 
     explicit local_datetime(const std::time_t t)
@@ -357,10 +399,31 @@ struct local_datetime
     {
         using internal_duration =
             typename std::chrono::system_clock::time_point::duration;
+
+        // Normally DST begins at A.M. 3 or 4. If we re-use conversion operator
+        // of local_date and local_time independently, the conversion fails if
+        // it is the day when DST begins or ends. Since local_date considers the
+        // time is 00:00 A.M. and local_time does not consider DST because it
+        // does not have any date information. We need to consider both date and
+        // time information at the same time to convert it correctly.
+
+        std::tm t;
+        t.tm_sec   = static_cast<int>(this->time.second);
+        t.tm_min   = static_cast<int>(this->time.minute);
+        t.tm_hour  = static_cast<int>(this->time.hour);
+        t.tm_mday  = static_cast<int>(this->date.day);
+        t.tm_mon   = static_cast<int>(this->date.month);
+        t.tm_year  = static_cast<int>(this->date.year) - 1900;
+        t.tm_wday  = 0; // the value will be ignored
+        t.tm_yday  = 0; // the value will be ignored
+        t.tm_isdst = -1;
+
         // std::mktime returns date as local time zone. no conversion needed
-        auto dt = std::chrono::system_clock::time_point(this->date);
+        auto dt = std::chrono::system_clock::from_time_t(std::mktime(&t));
         dt += std::chrono::duration_cast<internal_duration>(
-                   std::chrono::nanoseconds(this->time));
+                std::chrono::milliseconds(this->time.millisecond) +
+                std::chrono::microseconds(this->time.microsecond) +
+                std::chrono::nanoseconds (this->time.nanosecond));
         return dt;
     }
 
@@ -415,9 +478,9 @@ operator<<(std::basic_ostream<charT, traits>& os, const local_datetime& dt)
 
 struct offset_datetime
 {
-    local_date  date;
-    local_time  time;
-    time_offset offset;
+    local_date  date{};
+    local_time  time{};
+    time_offset offset{};
 
     offset_datetime(local_date d, local_time t, time_offset o)
         : date(d), time(t), offset(o)
@@ -426,40 +489,71 @@ struct offset_datetime
         : date(dt.date), time(dt.time), offset(o)
     {}
     explicit offset_datetime(const local_datetime& ld)
-        : date(ld.date), time(ld.time), offset(get_local_offset())
+        : date(ld.date), time(ld.time), offset(get_local_offset(nullptr))
+          // use the current local timezone offset
     {}
     explicit offset_datetime(const std::chrono::system_clock::time_point& tp)
-        : offset_datetime(local_datetime(tp))
-    {}
+        : offset(0, 0) // use gmtime
+    {
+        const auto timet = std::chrono::system_clock::to_time_t(tp);
+        const auto tm    = detail::gmtime_s(&timet);
+        this->date = local_date(tm);
+        this->time = local_time(tm);
+    }
     explicit offset_datetime(const std::time_t& t)
-        : offset_datetime(local_datetime(t))
-    {}
+        : offset(0, 0) // use gmtime
+    {
+        const auto tm    = detail::gmtime_s(&t);
+        this->date = local_date(tm);
+        this->time = local_time(tm);
+    }
     explicit offset_datetime(const std::tm& t)
-        : offset_datetime(local_datetime(t))
-    {}
+        : offset(0, 0) // assume gmtime
+    {
+        this->date = local_date(t);
+        this->time = local_time(t);
+    }
 
     operator std::chrono::system_clock::time_point() const
     {
         // get date-time
         using internal_duration =
             typename std::chrono::system_clock::time_point::duration;
-        std::chrono::system_clock::time_point tp =
-            std::chrono::system_clock::time_point(this->date) +
-            std::chrono::duration_cast<internal_duration>(
-                   std::chrono::nanoseconds(this->time));
 
-        // get date-time in UTC. let's say we are in +09:00 (JPN).
-        // writing 12:00:00 in +09:00 means 03:00:00Z. to represent
-        // 12:00:00Z, first we need to add +09:00.
-        const auto ofs = get_local_offset();
+        // first, convert it to local date-time information in the same way as
+        // local_datetime does. later we will use time_t to adjust time offset.
+        std::tm t;
+        t.tm_sec   = static_cast<int>(this->time.second);
+        t.tm_min   = static_cast<int>(this->time.minute);
+        t.tm_hour  = static_cast<int>(this->time.hour);
+        t.tm_mday  = static_cast<int>(this->date.day);
+        t.tm_mon   = static_cast<int>(this->date.month);
+        t.tm_year  = static_cast<int>(this->date.year) - 1900;
+        t.tm_wday  = 0; // the value will be ignored
+        t.tm_yday  = 0; // the value will be ignored
+        t.tm_isdst = -1;
+        const std::time_t tp_loc = std::mktime(std::addressof(t));
+
+        auto tp = std::chrono::system_clock::from_time_t(tp_loc);
+        tp += std::chrono::duration_cast<internal_duration>(
+                std::chrono::milliseconds(this->time.millisecond) +
+                std::chrono::microseconds(this->time.microsecond) +
+                std::chrono::nanoseconds (this->time.nanosecond));
+
+        // Since mktime uses local time zone, it should be corrected.
+        // `12:00:00+09:00` means `03:00:00Z`. So mktime returns `03:00:00Z` if
+        // we are in `+09:00` timezone. To represent `12:00:00Z` there, we need
+        // to add `+09:00` to `03:00:00Z`.
+        //    Here, it uses the time_t converted from date-time info to handle
+        // daylight saving time.
+        const auto ofs = get_local_offset(std::addressof(tp_loc));
         tp += std::chrono::hours  (ofs.hour);
         tp += std::chrono::minutes(ofs.minute);
 
-        // here, tp represents 12:00:00 in UTC but we have offset information.
-        // we need to subtract it. For example, let's say the input is
-        // 12:00:00-08:00. now we have tp = 12:00:00Z as a result of the above
-        // conversion. But the actual time we need to return is 20:00:00Z
-        // because of -08:00.
+        // We got `12:00:00Z` by correcting local timezone applied by mktime.
+        // Then we will apply the offset. Let's say `12:00:00-08:00` is given.
+        // And now, we have `12:00:00Z`. `12:00:00-08:00` means `20:00:00Z`.
+        // So we need to subtract the offset.
         tp -= std::chrono::minutes(this->offset);
         return tp;
     }
@@ -479,13 +573,10 @@ struct offset_datetime
 
   private:
 
-    static time_offset get_local_offset()
+    static time_offset get_local_offset(const std::time_t* tp)
     {
-         // get current timezone
-        const auto  tmp1 = std::time(nullptr);
-        const auto  tmp2 = std::localtime(&tmp1); // XXX not threadsafe!
-        assert(tmp2);
-        std::tm t = *tmp2;
+        // get local timezone with the same date-time information as mktime
+        const auto t = detail::localtime_s(tp);
 
         std::array<char, 6> buf;
         const auto result = std::strftime(buf.data(), 6, "%z", &t); // +hhmm\0

toml/exception.hpp

@@ -1,25 +1,51 @@
 //     Copyright Toru Niina 2017.
 // Distributed under the MIT License.
-#ifndef TOML11_EXCEPTION
-#define TOML11_EXCEPTION
-#include <stdexcept>
+#ifndef TOML11_EXCEPTION_HPP
+#define TOML11_EXCEPTION_HPP
+
+#include <array>
 #include <string>
+#include <stdexcept>
+
+#include <cstring>
+
+#include "source_location.hpp"
 
 namespace toml
 {
 
+struct file_io_error : public std::runtime_error
+{
+  public:
+    file_io_error(int errnum, const std::string& msg, const std::string& fname)
+        : std::runtime_error(msg + " \"" + fname + "\": errno = " + std::to_string(errnum)),
+          errno_(errnum)
+    {}
+
+    int get_errno() const noexcept {return errno_;}
+
+  private:
+    int errno_;
+};
+
 struct exception : public std::exception
 {
   public:
+    explicit exception(const source_location& loc): loc_(loc) {}
     virtual ~exception() noexcept override = default;
     virtual const char* what() const noexcept override {return "";}
+    virtual source_location const& location() const noexcept {return loc_;}
+
+  protected:
+    source_location loc_;
 };
 
 struct syntax_error : public toml::exception
 {
   public:
-    explicit syntax_error(const std::string& what_arg) : what_(what_arg){}
-    explicit syntax_error(const char* what_arg)        : what_(what_arg){}
+    explicit syntax_error(const std::string& what_arg, const source_location& loc)
+        : exception(loc), what_(what_arg)
+    {}
     virtual ~syntax_error() noexcept override = default;
     virtual const char* what() const noexcept override {return what_.c_str();}
 
@@ -30,8 +56,9 @@ struct syntax_error : public toml::exception
 struct type_error : public toml::exception
 {
   public:
-    explicit type_error(const std::string& what_arg) : what_(what_arg){}
-    explicit type_error(const char* what_arg)        : what_(what_arg){}
+    explicit type_error(const std::string& what_arg, const source_location& loc)
+        : exception(loc), what_(what_arg)
+    {}
     virtual ~type_error() noexcept override = default;
     virtual const char* what() const noexcept override {return what_.c_str();}
 
@@ -42,10 +69,12 @@ struct type_error : public toml::exception
 struct internal_error : public toml::exception
 {
   public:
-    explicit internal_error(const std::string& what_arg) : what_(what_arg){}
-    explicit internal_error(const char* what_arg)        : what_(what_arg){}
+    explicit internal_error(const std::string& what_arg, const source_location& loc)
+        : exception(loc), what_(what_arg)
+    {}
     virtual ~internal_error() noexcept override = default;
     virtual const char* what() const noexcept override {return what_.c_str();}
+
   protected:
     std::string what_;
 };

toml/from.hpp

@@ -0,0 +1,19 @@
+//     Copyright Toru Niina 2019.
+// Distributed under the MIT License.
+#ifndef TOML11_FROM_HPP
+#define TOML11_FROM_HPP
+
+namespace toml
+{
+
+template<typename T>
+struct from;
+// {
+//     static T from_toml(const toml::value& v)
+//     {
+//         // User-defined conversions ...
+//     }
+// };
+
+} // toml
+#endif // TOML11_FROM_HPP

toml/from_toml.hpp

@@ -1,71 +0,0 @@
-//     Copyright Toru Niina 2017.
-// Distributed under the MIT License.
-#ifndef TOML11_FROM_TOML
-#define TOML11_FROM_TOML
-#include "get.hpp"
-
-namespace toml
-{
-
-template<typename T>
-void from_toml(T& x, const toml::value& v)
-{
-    x = toml::get<typename std::remove_reference<T>::type>(v);
-    return;
-}
-
-namespace detail
-{
-
-template<typename T>
-constexpr toml::value_t determine_castable_type()
-{
-    return check_type<T>() != toml::value_t::Unknown ? check_type<T>() :
-           toml::detail::is_map<T>::value            ? toml::value_t::Table :
-           toml::detail::is_container<T>::value      ? toml::value_t::Array :
-           toml::value_t::Unknown;
-}
-
-template<std::size_t N, typename ... Ts>
-struct from_toml_tie_impl
-{
-    constexpr static std::size_t   index = sizeof...(Ts) - N;
-    constexpr static toml::value_t type_index =
-        determine_castable_type<
-            typename std::tuple_element<index, std::tuple<Ts...>>::type>();
-
-    static void invoke(std::tuple<Ts& ...> tie, const toml::value& v)
-    {
-        // static_cast is needed because with intel c++ compiler, operator==
-        // is only defined when the two types are strictly equal, and type_index
-        // is const toml::value_t, while v.type() is toml::value_t.
-        if(static_cast<toml::value_t>(type_index) == v.type())
-        {
-            from_toml(std::get<index>(tie), v);
-            return;
-        }
-        return from_toml_tie_impl<N-1, Ts...>::invoke(tie, v);
-    }
-};
-
-template<typename ... Ts>
-struct from_toml_tie_impl<0, Ts...>
-{
-    static void invoke(std::tuple<Ts& ...> tie, const toml::value& v)
-    {
-        return;
-    }
-};
-
-} // detail
-
-template<typename ... Ts>
-void from_toml(std::tuple<Ts& ...> tie, const toml::value& v)
-{
-    detail::from_toml_tie_impl<sizeof...(Ts), Ts...>::invoke(tie, v);
-    return;
-}
-
-
-} // toml
-#endif // TOML11_FROM_TOML

toml/into.hpp

@@ -0,0 +1,19 @@
+//     Copyright Toru Niina 2019.
+// Distributed under the MIT License.
+#ifndef TOML11_INTO_HPP
+#define TOML11_INTO_HPP
+
+namespace toml
+{
+
+template<typename T>
+struct into;
+// {
+//     static toml::value into_toml(const T& user_defined_type)
+//     {
+//         // User-defined conversions ...
+//     }
+// };
+
+} // toml
+#endif // TOML11_INTO_HPP

toml/lexer.hpp

@@ -2,11 +2,11 @@
 // Distributed under the MIT License.
 #ifndef TOML11_LEXER_HPP
 #define TOML11_LEXER_HPP
-#include "combinator.hpp"
-#include <stdexcept>
 #include <istream>
 #include <sstream>
-#include <fstream>
+#include <stdexcept>
+
+#include "combinator.hpp"
 
 namespace toml
 {
@@ -63,12 +63,15 @@ using lex_integer = either<lex_bin_int, lex_oct_int, lex_hex_int, lex_dec_int>;
 using lex_inf = sequence<character<'i'>, character<'n'>, character<'f'>>;
 using lex_nan = sequence<character<'n'>, character<'a'>, character<'n'>>;
 using lex_special_float = sequence<maybe<lex_sign>, either<lex_inf, lex_nan>>;
-using lex_exponent_part = sequence<either<character<'e'>, character<'E'>>, lex_dec_int>;
 
 using lex_zero_prefixable_int = sequence<lex_digit, repeat<either<lex_digit,
-      sequence<lex_underscore, lex_digit>>, unlimited>>;
+    sequence<lex_underscore, lex_digit>>, unlimited>>;
+
 using lex_fractional_part = sequence<character<'.'>, lex_zero_prefixable_int>;
 
+using lex_exponent_part   = sequence<either<character<'e'>, character<'E'>>,
+        maybe<lex_sign>, lex_zero_prefixable_int>;
+
 using lex_float = either<lex_special_float,
       sequence<lex_dec_int, either<lex_exponent_part,
       sequence<lex_fractional_part, maybe<lex_exponent_part>>>>>;
@@ -115,18 +118,23 @@ using lex_local_time       = lex_partial_time;
 // ===========================================================================
 
 using lex_quotation_mark  = character<'"'>;
-using lex_basic_unescaped = exclude<either<in_range<0x00, 0x1F>,
+using lex_basic_unescaped = exclude<either<in_range<0x00, 0x08>, // 0x09 (tab) is allowed
+                                           in_range<0x0A, 0x1F>,
                                            character<0x22>, character<0x5C>,
                                            character<0x7F>>>;
+
 using lex_escape          = character<'\\'>;
 using lex_escape_unicode_short = sequence<character<'u'>,
                                           repeat<lex_hex_dig, exactly<4>>>;
 using lex_escape_unicode_long  = sequence<character<'U'>,
                                           repeat<lex_hex_dig, exactly<8>>>;
 using lex_escape_seq_char = either<character<'"'>, character<'\\'>,
-                                   character<'/'>, character<'b'>,
-                                   character<'f'>, character<'n'>,
-                                   character<'r'>, character<'t'>,
+                                   character<'b'>, character<'f'>,
+                                   character<'n'>, character<'r'>,
+                                   character<'t'>,
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+                                   character<'e'>, // ESC (0x1B)
+#endif
                                    lex_escape_unicode_short,
                                    lex_escape_unicode_long
                                    >;
@@ -136,10 +144,46 @@ using lex_basic_string = sequence<lex_quotation_mark,
                                   repeat<lex_basic_char, unlimited>,
                                   lex_quotation_mark>;
 
+// After toml post-v0.5.0, it is explicitly clarified how quotes in ml-strings
+// are allowed to be used.
+// After this, the following strings are *explicitly* allowed.
+// - One or two `"`s in a multi-line basic string is allowed wherever it is.
+// - Three consecutive `"`s in a multi-line basic string is considered as a delimiter.
+// - One or two `"`s can appear just before or after the delimiter.
+// ```toml
+// str4 = """Here are two quotation marks: "". Simple enough."""
+// str5 = """Here are three quotation marks: ""\"."""
+// str6 = """Here are fifteen quotation marks: ""\"""\"""\"""\"""\"."""
+// str7 = """"This," she said, "is just a pointless statement.""""
+// ```
+// In the current implementation (v3.3.0), it is difficult to parse `str7` in
+// the above example. It is difficult to recognize `"` at the end of string body
+// collectly. It will be misunderstood as a `"""` delimiter and an additional,
+// invalid `"`. Like this:
+// ```console
+//   what():  [error] toml::parse_table: invalid line format
+//  --> hoge.toml
+//     |
+//  13 | str7 = """"This," she said, "is just a pointless statement.""""
+//     |                                                               ^- expected newline, but got '"'.
+// ```
+// As a quick workaround for this problem, `lex_ml_basic_string_delim` was
+// split into two, `lex_ml_basic_string_open` and `lex_ml_basic_string_close`.
+// `lex_ml_basic_string_open` allows only `"""`. `_close` allows 3-5 `"`s.
+// In parse_ml_basic_string() function, the trailing `"`s will be attached to
+// the string body.
+//
 using lex_ml_basic_string_delim = repeat<lex_quotation_mark, exactly<3>>;
-using lex_ml_basic_unescaped    = exclude<either<in_range<0x00, 0x1F>,
-                                                 character<0x5C>,
-                                                 character<0x7F>,
+using lex_ml_basic_string_open  = lex_ml_basic_string_delim;
+using lex_ml_basic_string_close = sequence<
+        repeat<lex_quotation_mark, exactly<3>>,
+        maybe<lex_quotation_mark>, maybe<lex_quotation_mark>
+    >;
+
+using lex_ml_basic_unescaped    = exclude<either<in_range<0x00, 0x08>, // 0x09 is tab
+                                                 in_range<0x0A, 0x1F>,
+                                                 character<0x5C>, // backslash
+                                                 character<0x7F>, // DEL
                                                  lex_ml_basic_string_delim>>;
 
 using lex_ml_basic_escaped_newline = sequence<
@@ -150,39 +194,39 @@ using lex_ml_basic_char = either<lex_ml_basic_unescaped, lex_escaped>;
 using lex_ml_basic_body = repeat<either<lex_ml_basic_char, lex_newline,
                                         lex_ml_basic_escaped_newline>,
                                  unlimited>;
-using lex_ml_basic_string = sequence<lex_ml_basic_string_delim,
+using lex_ml_basic_string = sequence<lex_ml_basic_string_open,
                                      lex_ml_basic_body,
-                                     lex_ml_basic_string_delim>;
+                                     lex_ml_basic_string_close>;
 
-using lex_literal_char = exclude<either<in_range<0x00, 0x08>,
-                                        in_range<0x10, 0x19>, character<0x27>>>;
+using lex_literal_char = exclude<either<in_range<0x00, 0x08>, in_range<0x0A, 0x1F>,
+                                        character<0x7F>, character<0x27>>>;
 using lex_apostrophe = character<'\''>;
 using lex_literal_string = sequence<lex_apostrophe,
                                     repeat<lex_literal_char, unlimited>,
                                     lex_apostrophe>;
 
+// the same reason as above.
 using lex_ml_literal_string_delim = repeat<lex_apostrophe, exactly<3>>;
+using lex_ml_literal_string_open  = lex_ml_literal_string_delim;
+using lex_ml_literal_string_close = sequence<
+        repeat<lex_apostrophe, exactly<3>>,
+        maybe<lex_apostrophe>, maybe<lex_apostrophe>
+    >;
 
 using lex_ml_literal_char = exclude<either<in_range<0x00, 0x08>,
-                                           in_range<0x10, 0x1F>,
+                                           in_range<0x0A, 0x1F>,
                                            character<0x7F>,
                                            lex_ml_literal_string_delim>>;
 using lex_ml_literal_body = repeat<either<lex_ml_literal_char, lex_newline>,
                                    unlimited>;
-using lex_ml_literal_string = sequence<lex_ml_literal_string_delim,
+using lex_ml_literal_string = sequence<lex_ml_literal_string_open,
                                        lex_ml_literal_body,
-                                       lex_ml_literal_string_delim>;
+                                       lex_ml_literal_string_close>;
 
 using lex_string = either<lex_ml_basic_string,   lex_basic_string,
                           lex_ml_literal_string, lex_literal_string>;
 
 // ===========================================================================
-
-using lex_comment_start_symbol = character<'#'>;
-using lex_non_eol = either<character<'\t'>, exclude<in_range<0x00, 0x19>>>;
-using lex_comment = sequence<lex_comment_start_symbol,
-                             repeat<lex_non_eol, unlimited>>;
-
 using lex_dot_sep = sequence<maybe<lex_ws>, character<'.'>, maybe<lex_ws>>;
 
 using lex_unquoted_key = repeat<either<lex_alpha, lex_digit,
@@ -217,6 +261,34 @@ using lex_array_table       = sequence<lex_array_table_open,
                                        maybe<lex_ws>,
                                        lex_array_table_close>;
 
+using lex_utf8_1byte = in_range<0x00, 0x7F>;
+using lex_utf8_2byte = sequence<
+        in_range<'\xC2', '\xDF'>,
+        in_range<'\x80', '\xBF'>
+    >;
+using lex_utf8_3byte = sequence<either<
+        sequence<character<'\xE0'>, in_range<'\xA0', '\xBF'>>,
+        sequence<in_range<'\xE1', '\xEC'>, in_range<'\x80', '\xBF'>>,
+        sequence<character<'\xED'>, in_range<'\x80', '\x9F'>>,
+        sequence<in_range<'\xEE', '\xEF'>, in_range<'\x80', '\xBF'>>
+    >, in_range<'\x80', '\xBF'>>;
+using lex_utf8_4byte = sequence<either<
+        sequence<character<'\xF0'>, in_range<'\x90', '\xBF'>>,
+        sequence<in_range<'\xF1', '\xF3'>, in_range<'\x80', '\xBF'>>,
+        sequence<character<'\xF4'>, in_range<'\x80', '\x8F'>>
+    >, in_range<'\x80', '\xBF'>, in_range<'\x80', '\xBF'>>;
+using lex_utf8_code = either<
+        lex_utf8_1byte,
+        lex_utf8_2byte,
+        lex_utf8_3byte,
+        lex_utf8_4byte
+    >;
+
+using lex_comment_start_symbol = character<'#'>;
+using lex_non_eol_ascii = either<character<0x09>, in_range<0x20, 0x7E>>;
+using lex_comment = sequence<lex_comment_start_symbol, repeat<either<
+    lex_non_eol_ascii, lex_utf8_2byte, lex_utf8_3byte, lex_utf8_4byte>, unlimited>>;
+
 } // detail
 } // toml
 #endif // TOML_LEXER_HPP

toml/literal.hpp

@@ -0,0 +1,113 @@
+//     Copyright Toru Niina 2019.
+// Distributed under the MIT License.
+#ifndef TOML11_LITERAL_HPP
+#define TOML11_LITERAL_HPP
+#include "parser.hpp"
+
+namespace toml
+{
+inline namespace literals
+{
+inline namespace toml_literals
+{
+
+// implementation
+inline ::toml::basic_value<TOML11_DEFAULT_COMMENT_STRATEGY, std::unordered_map, std::vector>
+literal_internal_impl(::toml::detail::location loc)
+{
+    using value_type = ::toml::basic_value<
+        TOML11_DEFAULT_COMMENT_STRATEGY, std::unordered_map, std::vector>;
+    // if there are some comments or empty lines, skip them.
+    using skip_line = ::toml::detail::repeat<toml::detail::sequence<
+            ::toml::detail::maybe<::toml::detail::lex_ws>,
+            ::toml::detail::maybe<::toml::detail::lex_comment>,
+            ::toml::detail::lex_newline
+        >, ::toml::detail::at_least<1>>;
+    skip_line::invoke(loc);
+
+    // if there are some whitespaces before a value, skip them.
+    using skip_ws = ::toml::detail::repeat<
+        ::toml::detail::lex_ws, ::toml::detail::at_least<1>>;
+    skip_ws::invoke(loc);
+
+    // to distinguish arrays and tables, first check it is a table or not.
+    //
+    // "[1,2,3]"_toml;   // this is an array
+    // "[table]"_toml;   // a table that has an empty table named "table" inside.
+    // "[[1,2,3]]"_toml; // this is an array of arrays
+    // "[[table]]"_toml; // this is a table that has an array of tables inside.
+    //
+    // "[[1]]"_toml;     // this can be both... (currently it becomes a table)
+    // "1 = [{}]"_toml;  // this is a table that has an array of table named 1.
+    // "[[1,]]"_toml;    // this is an array of arrays.
+    // "[[1],]"_toml;    // this also.
+
+    const auto the_front = loc.iter();
+
+    const bool is_table_key = ::toml::detail::lex_std_table::invoke(loc);
+    loc.reset(the_front);
+
+    const bool is_aots_key  = ::toml::detail::lex_array_table::invoke(loc);
+    loc.reset(the_front);
+
+    // If it is neither a table-key or a array-of-table-key, it may be a value.
+    if(!is_table_key && !is_aots_key)
+    {
+        if(auto data = ::toml::detail::parse_value<value_type>(loc, 0))
+        {
+            return data.unwrap();
+        }
+    }
+
+    // Note that still it can be a table, because the literal might be something
+    // like the following.
+    // ```cpp
+    // R"( // c++11 raw string literals
+    //   key = "value"
+    //   int = 42
+    // )"_toml;
+    // ```
+    // It is a valid toml file.
+    // It should be parsed as if we parse a file with this content.
+
+    if(auto data = ::toml::detail::parse_toml_file<value_type>(loc))
+    {
+        return data.unwrap();
+    }
+    else // none of them.
+    {
+        throw ::toml::syntax_error(data.unwrap_err(), source_location(loc));
+    }
+
+}
+
+inline ::toml::basic_value<TOML11_DEFAULT_COMMENT_STRATEGY, std::unordered_map, std::vector>
+operator"" _toml(const char* str, std::size_t len)
+{
+    ::toml::detail::location loc(
+            std::string("TOML literal encoded in a C++ code"),
+            std::vector<char>(str, str + len));
+    // literal length does not include the null character at the end.
+    return literal_internal_impl(std::move(loc));
+}
+
+// value of __cplusplus in C++2a/20 mode is not fixed yet along compilers.
+// So here we use the feature test macro for `char8_t` itself.
+#if defined(__cpp_char8_t) && __cpp_char8_t >= 201811L
+// value of u8"" literal has been changed from char to char8_t and char8_t is
+// NOT compatible to char
+inline ::toml::basic_value<TOML11_DEFAULT_COMMENT_STRATEGY, std::unordered_map, std::vector>
+operator"" _toml(const char8_t* str, std::size_t len)
+{
+    ::toml::detail::location loc(
+            std::string("TOML literal encoded in a C++ code"),
+            std::vector<char>(reinterpret_cast<const char*>(str),
+                              reinterpret_cast<const char*>(str) + len));
+    return literal_internal_impl(std::move(loc));
+}
+#endif
+
+} // toml_literals
+} // literals
+} // toml
+#endif//TOML11_LITERAL_HPP

toml/macros.hpp

@@ -0,0 +1,121 @@
+#ifndef TOML11_MACROS_HPP
+#define TOML11_MACROS_HPP
+
+#define TOML11_STRINGIZE_AUX(x) #x
+#define TOML11_STRINGIZE(x)     TOML11_STRINGIZE_AUX(x)
+
+#define TOML11_CONCATENATE_AUX(x, y) x##y
+#define TOML11_CONCATENATE(x, y)     TOML11_CONCATENATE_AUX(x, y)
+
+// ============================================================================
+// TOML11_DEFINE_CONVERSION_NON_INTRUSIVE
+
+#ifndef TOML11_WITHOUT_DEFINE_NON_INTRUSIVE
+
+// ----------------------------------------------------------------------------
+// TOML11_ARGS_SIZE
+
+#define TOML11_INDEX_RSEQ() \
+    32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, \
+    16, 15, 14, 13, 12, 11, 10,  9,  8,  7,  6,  5,  4,  3,  2,  1, 0
+#define TOML11_ARGS_SIZE_IMPL(\
+    ARG1,  ARG2,  ARG3,  ARG4,  ARG5,  ARG6,  ARG7,  ARG8,  ARG9,  ARG10, \
+    ARG11, ARG12, ARG13, ARG14, ARG15, ARG16, ARG17, ARG18, ARG19, ARG20, \
+    ARG21, ARG22, ARG23, ARG24, ARG25, ARG26, ARG27, ARG28, ARG29, ARG30, \
+    ARG31, ARG32, N, ...) N
+#define TOML11_ARGS_SIZE_AUX(...) TOML11_ARGS_SIZE_IMPL(__VA_ARGS__)
+#define TOML11_ARGS_SIZE(...) TOML11_ARGS_SIZE_AUX(__VA_ARGS__, TOML11_INDEX_RSEQ())
+
+// ----------------------------------------------------------------------------
+// TOML11_FOR_EACH_VA_ARGS
+
+#define TOML11_FOR_EACH_VA_ARGS_AUX_1( FUNCTOR, ARG1     ) FUNCTOR(ARG1)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_2( FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_1( FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_3( FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_2( FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_4( FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_3( FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_5( FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_4( FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_6( FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_5( FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_7( FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_6( FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_8( FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_7( FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_9( FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_8( FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_10(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_9( FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_11(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_10(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_12(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_11(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_13(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_12(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_14(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_13(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_15(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_14(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_16(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_15(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_17(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_16(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_18(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_17(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_19(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_18(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_20(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_19(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_21(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_20(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_22(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_21(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_23(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_22(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_24(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_23(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_25(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_24(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_26(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_25(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_27(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_26(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_28(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_27(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_29(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_28(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_30(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_29(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_31(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_30(FUNCTOR, __VA_ARGS__)
+#define TOML11_FOR_EACH_VA_ARGS_AUX_32(FUNCTOR, ARG1, ...) FUNCTOR(ARG1) TOML11_FOR_EACH_VA_ARGS_AUX_31(FUNCTOR, __VA_ARGS__)
+
+#define TOML11_FOR_EACH_VA_ARGS(FUNCTOR, ...)\
+    TOML11_CONCATENATE(TOML11_FOR_EACH_VA_ARGS_AUX_, TOML11_ARGS_SIZE(__VA_ARGS__))(FUNCTOR, __VA_ARGS__)
+
+// ----------------------------------------------------------------------------
+// TOML11_DEFINE_CONVERSION_NON_INTRUSIVE
+
+// use it in the following way.
+// ```cpp
+// namespace foo
+// {
+// struct Foo
+// {
+//     std::string s;
+//     double      d;
+//     int         i;
+// };
+// } // foo
+//
+// TOML11_DEFINE_CONVERSION_NON_INTRUSIVE(foo::Foo, s, d, i)
+// ```
+// And then you can use `toml::find<foo::Foo>(file, "foo");`
+//
+#define TOML11_FIND_MEMBER_VARIABLE_FROM_VALUE(VAR_NAME)\
+    obj.VAR_NAME = toml::find<decltype(obj.VAR_NAME)>(v, TOML11_STRINGIZE(VAR_NAME));
+
+#define TOML11_ASSIGN_MEMBER_VARIABLE_TO_VALUE(VAR_NAME)\
+    v[TOML11_STRINGIZE(VAR_NAME)] = obj.VAR_NAME;
+
+#define TOML11_DEFINE_CONVERSION_NON_INTRUSIVE(NAME, ...)\
+    namespace toml {                                                                     \
+    template<>                                                                           \
+    struct from<NAME>                                                                    \
+    {                                                                                    \
+        template<typename C, template<typename ...> class T,                             \
+                 template<typename ...> class A>                                         \
+        static NAME from_toml(const basic_value<C, T, A>& v)                             \
+        {                                                                                \
+            NAME obj;                                                                    \
+            TOML11_FOR_EACH_VA_ARGS(TOML11_FIND_MEMBER_VARIABLE_FROM_VALUE, __VA_ARGS__) \
+            return obj;                                                                  \
+        }                                                                                \
+    };                                                                                   \
+    template<>                                                                           \
+    struct into<NAME>                                                                    \
+    {                                                                                    \
+        static value into_toml(const NAME& obj)                                          \
+        {                                                                                \
+            ::toml::value v = ::toml::table{};                                           \
+            TOML11_FOR_EACH_VA_ARGS(TOML11_ASSIGN_MEMBER_VARIABLE_TO_VALUE, __VA_ARGS__) \
+            return v;                                                                    \
+        }                                                                                \
+    };                                                                                   \
+    } /* toml */
+
+#endif// TOML11_WITHOUT_DEFINE_NON_INTRUSIVE
+
+#endif// TOML11_MACROS_HPP

toml/region.hpp

@@ -1,21 +1,22 @@
 //     Copyright Toru Niina 2017.
 // Distributed under the MIT License.
-#ifndef TOML11_REGION_H
-#define TOML11_REGION_H
-#include "exception.hpp"
+#ifndef TOML11_REGION_HPP
+#define TOML11_REGION_HPP
 #include <memory>
 #include <vector>
 #include <algorithm>
 #include <initializer_list>
 #include <iterator>
 #include <iomanip>
+#include <cassert>
+#include "color.hpp"
 
 namespace toml
 {
 namespace detail
 {
 
-// helper function to avoid std::string(0, 'c')
+// helper function to avoid std::string(0, 'c') or std::string(iter, iter)
 template<typename Iterator>
 std::string make_string(Iterator first, Iterator last)
 {
@@ -28,47 +29,7 @@ inline std::string make_string(std::size_t len, char c)
     return std::string(len, c);
 }
 
-// location in a container, normally in a file content.
-// shared_ptr points the resource that the iter points.
-// it can be used not only for resource handling, but also error message.
-template<typename Container>
-struct location
-{
-    static_assert(std::is_same<char, typename Container::value_type>::value,"");
-    using const_iterator = typename Container::const_iterator;
-    using source_ptr     = std::shared_ptr<const Container>;
-
-    location(std::string name, Container cont)
-      : source_(std::make_shared<Container>(std::move(cont))),
-        source_name_(std::move(name)), iter_(source_->cbegin())
-    {}
-    location(const location&) = default;
-    location(location&&)      = default;
-    location& operator=(const location&) = default;
-    location& operator=(location&&)      = default;
-    ~location() = default;
-
-    const_iterator& iter()       noexcept {return iter_;}
-    const_iterator  iter() const noexcept {return iter_;}
-
-    const_iterator  begin() const noexcept {return source_->cbegin();}
-    const_iterator  end()   const noexcept {return source_->cend();}
-
-    source_ptr const& source() const& noexcept {return source_;}
-    source_ptr&&      source() &&     noexcept {return std::move(source_);}
-
-    std::string const& name() const noexcept {return source_name_;}
-
-  private:
-
-    source_ptr     source_;
-    std::string    source_name_;
-    const_iterator iter_;
-};
-
-// region in a container, normally in a file content.
-// shared_ptr points the resource that the iter points.
-// combinators returns this.
+// region_base is a base class of location and region that are defined below.
 // it will be used to generate better error messages.
 struct region_base
 {
@@ -80,41 +41,180 @@ struct region_base
     region_base& operator=(region_base&&     ) = default;
 
     virtual bool is_ok()           const noexcept {return false;}
+    virtual char front()           const noexcept {return '\0';}
 
     virtual std::string str()      const {return std::string("unknown region");}
     virtual std::string name()     const {return std::string("unknown file");}
     virtual std::string line()     const {return std::string("unknown line");}
     virtual std::string line_num() const {return std::string("?");}
 
-
-    virtual std::size_t before()   const noexcept {return 0;}
+    // length of the region
     virtual std::size_t size()     const noexcept {return 0;}
+    // number of characters in the line before the region
+    virtual std::size_t before()   const noexcept {return 0;}
+    // number of characters in the line after the region
     virtual std::size_t after()    const noexcept {return 0;}
+
+    virtual std::vector<std::string> comments() const {return {};}
+    // ```toml
+    // # comment_before
+    // key = "value" # comment_inline
+    // ```
 };
 
-template<typename Container>
+// location represents a position in a container, which contains a file content.
+// it can be considered as a region that contains only one character.
+//
+// it contains pointer to the file content and iterator that points the current
+// location.
+struct location final : public region_base
+{
+    using const_iterator  = typename std::vector<char>::const_iterator;
+    using difference_type = typename std::iterator_traits<const_iterator>::difference_type;
+    using source_ptr      = std::shared_ptr<const std::vector<char>>;
+
+    location(std::string source_name, std::vector<char> cont)
+      : source_(std::make_shared<std::vector<char>>(std::move(cont))),
+        line_number_(1), source_name_(std::move(source_name)), iter_(source_->cbegin())
+    {}
+    location(std::string source_name, const std::string& cont)
+      : source_(std::make_shared<std::vector<char>>(cont.begin(), cont.end())),
+        line_number_(1), source_name_(std::move(source_name)), iter_(source_->cbegin())
+    {}
+
+    location(const location&) = default;
+    location(location&&)      = default;
+    location& operator=(const location&) = default;
+    location& operator=(location&&)      = default;
+    ~location() = default;
+
+    bool is_ok() const noexcept override {return static_cast<bool>(source_);}
+    char front() const noexcept override {return *iter_;}
+
+    // this const prohibits codes like `++(loc.iter())`.
+    std::add_const<const_iterator>::type iter()  const noexcept {return iter_;}
+
+    const_iterator begin() const noexcept {return source_->cbegin();}
+    const_iterator end()   const noexcept {return source_->cend();}
+
+    // XXX `location::line_num()` used to be implemented using `std::count` to
+    // count a number of '\n'. But with a long toml file (typically, 10k lines),
+    // it becomes intolerably slow because each time it generates error messages,
+    // it counts '\n' from thousands of characters. To workaround it, I decided
+    // to introduce `location::line_number_` member variable and synchronize it
+    // to the location changes the point to look. So an overload of `iter()`
+    // which returns mutable reference is removed and `advance()`, `retrace()`
+    // and `reset()` is added.
+    void advance(difference_type n = 1) noexcept
+    {
+        this->line_number_ += static_cast<std::size_t>(
+                std::count(this->iter_, std::next(this->iter_, n), '\n'));
+        this->iter_ += n;
+        return;
+    }
+    void retrace(difference_type n = 1) noexcept
+    {
+        this->line_number_ -= static_cast<std::size_t>(
+                std::count(std::prev(this->iter_, n), this->iter_, '\n'));
+        this->iter_ -= n;
+        return;
+    }
+    void reset(const_iterator rollback) noexcept
+    {
+        // since c++11, std::distance works in both ways for random-access
+        // iterators and returns a negative value if `first > last`.
+        if(0 <= std::distance(rollback, this->iter_)) // rollback < iter
+        {
+            this->line_number_ -= static_cast<std::size_t>(
+                    std::count(rollback, this->iter_, '\n'));
+        }
+        else // iter < rollback [[unlikely]]
+        {
+            this->line_number_ += static_cast<std::size_t>(
+                    std::count(this->iter_, rollback, '\n'));
+        }
+        this->iter_ = rollback;
+        return;
+    }
+
+    std::string str()  const override {return make_string(1, *this->iter());}
+    std::string name() const override {return source_name_;}
+
+    std::string line_num() const override
+    {
+        return std::to_string(this->line_number_);
+    }
+
+    std::string line() const override
+    {
+        return make_string(this->line_begin(), this->line_end());
+    }
+
+    const_iterator line_begin() const noexcept
+    {
+        using reverse_iterator = std::reverse_iterator<const_iterator>;
+        return std::find(reverse_iterator(this->iter()),
+                         reverse_iterator(this->begin()), '\n').base();
+    }
+    const_iterator line_end() const noexcept
+    {
+        return std::find(this->iter(), this->end(), '\n');
+    }
+
+    // location is always points a character. so the size is 1.
+    std::size_t size() const noexcept override
+    {
+        return 1u;
+    }
+    std::size_t before() const noexcept override
+    {
+        const auto sz = std::distance(this->line_begin(), this->iter());
+        assert(sz >= 0);
+        return static_cast<std::size_t>(sz);
+    }
+    std::size_t after() const noexcept override
+    {
+        const auto sz = std::distance(this->iter(), this->line_end());
+        assert(sz >= 0);
+        return static_cast<std::size_t>(sz);
+    }
+
+    source_ptr const& source() const& noexcept {return source_;}
+    source_ptr&&      source() &&     noexcept {return std::move(source_);}
+
+  private:
+
+    source_ptr     source_;
+    std::size_t    line_number_;
+    std::string    source_name_;
+    const_iterator iter_;
+};
+
+// region represents a range in a container, which contains a file content.
+//
+// it contains pointer to the file content and iterator that points the first
+// and last location.
 struct region final : public region_base
 {
-    static_assert(std::is_same<char, typename Container::value_type>::value,"");
-    using const_iterator = typename Container::const_iterator;
-    using source_ptr     = std::shared_ptr<const Container>;
+    using const_iterator = typename std::vector<char>::const_iterator;
+    using source_ptr     = std::shared_ptr<const std::vector<char>>;
 
     // delete default constructor. source_ never be null.
     region() = delete;
 
-    region(const location<Container>& loc)
+    explicit region(const location& loc)
       : source_(loc.source()), source_name_(loc.name()),
         first_(loc.iter()), last_(loc.iter())
     {}
-    region(location<Container>&& loc)
+    explicit region(location&& loc)
       : source_(loc.source()), source_name_(loc.name()),
         first_(loc.iter()), last_(loc.iter())
     {}
 
-    region(const location<Container>& loc, const_iterator f, const_iterator l)
+    region(const location& loc, const_iterator f, const_iterator l)
       : source_(loc.source()), source_name_(loc.name()), first_(f), last_(l)
     {}
-    region(location<Container>&& loc, const_iterator f, const_iterator l)
+    region(location&& loc, const_iterator f, const_iterator l)
       : source_(loc.source()), source_name_(loc.name()), first_(f), last_(l)
     {}
 
@@ -126,16 +226,15 @@ struct region final : public region_base
 
     region& operator+=(const region& other)
     {
-        if(this->begin() != other.begin() || this->end() != other.end() ||
-           this->last_  != other.first_)
-        {
-            throw internal_error("invalid region concatenation");
-        }
+        // different regions cannot be concatenated
+        assert(this->source_ == other.source_ && this->last_ == other.first_);
+
         this->last_ = other.last_;
         return *this;
     }
 
     bool is_ok() const noexcept override {return static_cast<bool>(source_);}
+    char front() const noexcept override {return *first_;}
 
     std::string str()  const override {return make_string(first_, last_);}
     std::string line() const override
@@ -154,15 +253,21 @@ struct region final : public region_base
 
     std::size_t size() const noexcept override
     {
-        return std::distance(first_, last_);
+        const auto sz = std::distance(first_, last_);
+        assert(sz >= 0);
+        return static_cast<std::size_t>(sz);
     }
     std::size_t before() const noexcept override
     {
-        return std::distance(this->line_begin(), this->first());
+        const auto sz = std::distance(this->line_begin(), this->first());
+        assert(sz >= 0);
+        return static_cast<std::size_t>(sz);
     }
     std::size_t after() const noexcept override
     {
-        return std::distance(this->last(), this->line_end());
+        const auto sz = std::distance(this->last(), this->line_end());
+        assert(sz >= 0);
+        return static_cast<std::size_t>(sz);
     }
 
     bool contain_newline() const noexcept
@@ -191,6 +296,114 @@ struct region final : public region_base
 
     std::string name() const override {return source_name_;}
 
+    std::vector<std::string> comments() const override
+    {
+        // assuming the current region (`*this`) points a value.
+        // ```toml
+        // a = "value"
+        //     ^^^^^^^- this region
+        // ```
+        using rev_iter = std::reverse_iterator<const_iterator>;
+
+        std::vector<std::string> com{};
+        {
+            // find comments just before the current region.
+            // ```toml
+            // # this should be collected.
+            // # this also.
+            // a = value # not this.
+            // ```
+
+            // # this is a comment for `a`, not array elements.
+            // a = [1, 2, 3, 4, 5]
+            if(this->first() == std::find_if(this->line_begin(), this->first(),
+                [](const char c) noexcept -> bool {return c == '[' || c == '{';}))
+            {
+                auto iter = this->line_begin(); // points the first character
+                while(iter != this->begin())
+                {
+                    iter = std::prev(iter);
+
+                    // range [line_start, iter) represents the previous line
+                    const auto line_start   = std::find(
+                            rev_iter(iter), rev_iter(this->begin()), '\n').base();
+                    const auto comment_found = std::find(line_start, iter, '#');
+                    if(comment_found == iter)
+                    {
+                        break; // comment not found.
+                    }
+
+                    // exclude the following case.
+                    // > a = "foo" # comment // <-- this is not a comment for b but a.
+                    // > b = "current value"
+                    if(std::all_of(line_start, comment_found,
+                            [](const char c) noexcept -> bool {
+                                return c == ' ' || c == '\t';
+                            }))
+                    {
+                        // unwrap the first '#' by std::next.
+                        auto s = make_string(std::next(comment_found), iter);
+                        if(!s.empty() && s.back() == '\r') {s.pop_back();}
+                        com.push_back(std::move(s));
+                    }
+                    else
+                    {
+                        break;
+                    }
+                    iter = line_start;
+                }
+            }
+        }
+
+        if(com.size() > 1)
+        {
+            std::reverse(com.begin(), com.end());
+        }
+
+        {
+            // find comments just after the current region.
+            // ```toml
+            // # not this.
+            // a = value # this one.
+            // a = [ # not this (technically difficult)
+            //
+            // ] # and this.
+            // ```
+            // The reason why it's difficult is that it requires parsing in the
+            // following case.
+            // ```toml
+            // a = [ 10 # this comment is for `10`. not for `a` but `a[0]`.
+            // # ...
+            // ] # this is apparently a comment for a.
+            //
+            // b = [
+            // 3.14 ] # there is no way to add a comment to `3.14` currently.
+            //
+            // c = [
+            //   3.14 # do this if you need a comment here.
+            // ]
+            // ```
+            const auto comment_found =
+                std::find(this->last(), this->line_end(), '#');
+            if(comment_found != this->line_end()) // '#' found
+            {
+                // table = {key = "value"} # what is this for?
+                // the above comment is not for "value", but {key="value"}.
+                if(comment_found == std::find_if(this->last(), comment_found,
+                    [](const char c) noexcept -> bool {
+                        return !(c == ' ' || c == '\t' || c == ',');
+                    }))
+                {
+                    // unwrap the first '#' by std::next.
+                    auto s = make_string(std::next(comment_found), this->line_end());
+                    if(!s.empty() && s.back() == '\r') {s.pop_back();}
+                    com.push_back(std::move(s));
+                }
+            }
+        }
+        return com;
+    }
+
   private:
 
     source_ptr     source_;
@@ -198,169 +411,6 @@ struct region final : public region_base
     const_iterator first_, last_;
 };
 
-// to show a better error message.
-inline std::string format_underline(const std::string& message,
-        const region_base& reg, const std::string& comment_for_underline,
-        std::vector<std::string> helps = {})
-{
-#ifdef _WIN32
-    const auto newline = "\r\n";
-#else
-    const char newline = '\n';
-#endif
-    const auto line        = reg.line();
-    const auto line_number = reg.line_num();
-
-    std::string retval;
-    retval += message;
-    retval += newline;
-    retval += " --> ";
-    retval += reg.name();
-    retval += newline;
-    retval += ' ';
-    retval += line_number;
-    retval += " | ";
-    retval += line;
-    retval += newline;
-    retval += make_string(line_number.size() + 1, ' ');
-    retval += " | ";
-    retval += make_string(reg.before(), ' ');
-    retval += make_string(reg.size(),   '~');
-    retval += ' ';
-    retval += comment_for_underline;
-    if(helps.size() != 0)
-    {
-        retval += newline;
-        retval += make_string(line_number.size() + 1, ' ');
-        retval += " | ";
-        for(const auto help : helps)
-        {
-            retval += newline;
-            retval += "Hint: ";
-            retval += help;
-        }
-    }
-    return retval;
-}
-
-// to show a better error message.
-inline std::string format_underline(const std::string& message,
-        const region_base& reg1, const std::string& comment_for_underline1,
-        const region_base& reg2, const std::string& comment_for_underline2,
-        std::vector<std::string> helps = {})
-{
-#ifdef _WIN32
-    const auto newline = "\r\n";
-#else
-    const char newline = '\n';
-#endif
-    const auto line1        = reg1.line();
-    const auto line_number1 = reg1.line_num();
-    const auto line2        = reg2.line();
-    const auto line_number2 = reg2.line_num();
-    const auto line_num_width =
-        std::max(line_number1.size(), line_number2.size());
-
-    std::ostringstream retval;
-    retval << message << newline;
-    retval << " --> " << reg1.name() << newline;
-//  ---------------------------------------
-    retval << ' ' << std::setw(line_num_width) << line_number1;
-    retval << " | " << line1 << newline;
-    retval << make_string(line_num_width + 1, ' ');
-    retval << " | ";
-    retval << make_string(reg1.before(), ' ');
-    retval << make_string(reg1.size(),   '~');
-    retval << ' ';
-    retval << comment_for_underline1 << newline;
-//  ---------------------------------------
-    if(reg2.name() != reg1.name())
-    {
-        retval << " --> " << reg2.name() << newline;
-    }
-    else
-    {
-        retval << " ..." << newline;
-    }
-    retval << ' ' << std::setw(line_num_width) << line_number2;
-    retval << " | " << line2 << newline;
-    retval << make_string(line_num_width + 1, ' ');
-    retval << " | ";
-    retval << make_string(reg2.before(), ' ');
-    retval << make_string(reg2.size(),   '~');
-    retval << ' ';
-    retval << comment_for_underline2;
-    if(helps.size() != 0)
-    {
-        retval << newline;
-        retval << make_string(line_num_width + 1, ' ');
-        retval << " | ";
-        for(const auto help : helps)
-        {
-            retval << newline;
-            retval << "Hint: ";
-            retval << help;
-        }
-    }
-    return retval.str();
-}
-
-
-// to show a better error message.
-template<typename Container>
-std::string
-format_underline(const std::string& message, const location<Container>& loc,
-                 const std::string& comment_for_underline,
-                 std::vector<std::string> helps = {})
-{
-#ifdef _WIN32
-    const auto newline = "\r\n";
-#else
-    const char newline = '\n';
-#endif
-    using const_iterator   = typename location<Container>::const_iterator;
-    using reverse_iterator = std::reverse_iterator<const_iterator>;
-    const auto line_begin  = std::find(reverse_iterator(loc.iter()),
-                                       reverse_iterator(loc.begin()),
-                                       '\n').base();
-    const auto line_end    = std::find(loc.iter(), loc.end(), '\n');
-
-    const auto line_number = std::to_string(
-            1 + std::count(loc.begin(), loc.iter(), '\n'));
-
-    std::string retval;
-    retval += message;
-    retval += newline;
-    retval += " --> ";
-    retval += loc.name();
-    retval += newline;
-    retval += ' ';
-    retval += line_number;
-    retval += " | ";
-    retval += make_string(line_begin, line_end);
-    retval += newline;
-    retval += make_string(line_number.size() + 1, ' ');
-    retval += " | ";
-    retval += make_string(std::distance(line_begin, loc.iter()),' ');
-    retval += '^';
-    retval += make_string(std::distance(loc.iter(), line_end), '-');
-    retval += ' ';
-    retval += comment_for_underline;
-    if(helps.size() != 0)
-    {
-        retval += newline;
-        retval += make_string(line_number.size() + 1, ' ');
-        retval += " | ";
-        for(const auto help : helps)
-        {
-            retval += newline;
-            retval += "Hint: ";
-            retval += help;
-        }
-    }
-    return retval;
-}
-
 } // detail
 } // toml
 #endif// TOML11_REGION_H

toml/result.hpp

@@ -1,7 +1,8 @@
 //     Copyright Toru Niina 2017.
 // Distributed under the MIT License.
-#ifndef TOML11_RESULT_H
-#define TOML11_RESULT_H
+#ifndef TOML11_RESULT_HPP
+#define TOML11_RESULT_HPP
+#include "traits.hpp"
 #include <type_traits>
 #include <stdexcept>
 #include <utility>
@@ -13,19 +14,6 @@
 namespace toml
 {
 
-#if __cplusplus >= 201703L
-
-template<typename F, typename ... Args>
-using return_type_of_t = std::invoke_result_t<F, Args...>;
-
-#else
-// result_of is deprecated after C++17
-template<typename F, typename ... Args>
-using return_type_of_t = typename std::result_of<F(Args...)>::type;
-
-#endif
-
-
 template<typename T>
 struct success
 {
@@ -125,21 +113,25 @@ struct result
     {
         auto tmp = ::new(std::addressof(this->succ)) success_type(s);
         assert(tmp == std::addressof(this->succ));
+        (void)tmp;
     }
     result(const failure_type& f): is_ok_(false)
     {
         auto tmp = ::new(std::addressof(this->fail)) failure_type(f);
         assert(tmp == std::addressof(this->fail));
+        (void)tmp;
     }
     result(success_type&& s): is_ok_(true)
     {
         auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(s));
         assert(tmp == std::addressof(this->succ));
+        (void)tmp;
     }
     result(failure_type&& f): is_ok_(false)
     {
         auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(f));
         assert(tmp == std::addressof(this->fail));
+        (void)tmp;
     }
 
     template<typename U>
@@ -147,24 +139,28 @@ struct result
     {
         auto tmp = ::new(std::addressof(this->succ)) success_type(s.value);
         assert(tmp == std::addressof(this->succ));
+        (void)tmp;
     }
     template<typename U>
     result(const failure<U>& f): is_ok_(false)
     {
         auto tmp = ::new(std::addressof(this->fail)) failure_type(f.value);
         assert(tmp == std::addressof(this->fail));
+        (void)tmp;
     }
     template<typename U>
     result(success<U>&& s): is_ok_(true)
     {
         auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(s.value));
         assert(tmp == std::addressof(this->succ));
+        (void)tmp;
     }
     template<typename U>
     result(failure<U>&& f): is_ok_(false)
     {
         auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(f.value));
         assert(tmp == std::addressof(this->fail));
+        (void)tmp;
     }
 
     result& operator=(const success_type& s)
@@ -173,6 +169,7 @@ struct result
         this->is_ok_ = true;
         auto tmp = ::new(std::addressof(this->succ)) success_type(s);
         assert(tmp == std::addressof(this->succ));
+        (void)tmp;
         return *this;
     }
     result& operator=(const failure_type& f)
@@ -181,6 +178,7 @@ struct result
         this->is_ok_ = false;
         auto tmp = ::new(std::addressof(this->fail)) failure_type(f);
         assert(tmp == std::addressof(this->fail));
+        (void)tmp;
         return *this;
     }
     result& operator=(success_type&& s)
@@ -189,6 +187,7 @@ struct result
         this->is_ok_ = true;
         auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(s));
         assert(tmp == std::addressof(this->succ));
+        (void)tmp;
         return *this;
     }
     result& operator=(failure_type&& f)
@@ -197,6 +196,7 @@ struct result
         this->is_ok_ = false;
         auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(f));
         assert(tmp == std::addressof(this->fail));
+        (void)tmp;
         return *this;
     }
 
@@ -207,6 +207,7 @@ struct result
         this->is_ok_ = true;
         auto tmp = ::new(std::addressof(this->succ)) success_type(s.value);
         assert(tmp == std::addressof(this->succ));
+        (void)tmp;
         return *this;
     }
     template<typename U>
@@ -216,6 +217,7 @@ struct result
         this->is_ok_ = false;
         auto tmp = ::new(std::addressof(this->fail)) failure_type(f.value);
         assert(tmp == std::addressof(this->fail));
+        (void)tmp;
         return *this;
     }
     template<typename U>
@@ -225,6 +227,7 @@ struct result
         this->is_ok_ = true;
         auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(s.value));
         assert(tmp == std::addressof(this->succ));
+        (void)tmp;
         return *this;
     }
     template<typename U>
@@ -234,6 +237,7 @@ struct result
         this->is_ok_ = false;
         auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(f.value));
         assert(tmp == std::addressof(this->fail));
+        (void)tmp;
         return *this;
     }
 
@@ -245,11 +249,13 @@ struct result
         {
             auto tmp = ::new(std::addressof(this->succ)) success_type(other.as_ok());
             assert(tmp == std::addressof(this->succ));
+            (void)tmp;
         }
         else
         {
             auto tmp = ::new(std::addressof(this->fail)) failure_type(other.as_err());
             assert(tmp == std::addressof(this->fail));
+            (void)tmp;
         }
     }
     result(result&& other): is_ok_(other.is_ok())
@@ -258,11 +264,13 @@ struct result
         {
             auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(other.as_ok()));
             assert(tmp == std::addressof(this->succ));
+            (void)tmp;
         }
         else
         {
             auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(other.as_err()));
             assert(tmp == std::addressof(this->fail));
+            (void)tmp;
         }
     }
 
@@ -273,11 +281,13 @@ struct result
         {
             auto tmp = ::new(std::addressof(this->succ)) success_type(other.as_ok());
             assert(tmp == std::addressof(this->succ));
+            (void)tmp;
         }
         else
         {
             auto tmp = ::new(std::addressof(this->fail)) failure_type(other.as_err());
             assert(tmp == std::addressof(this->fail));
+            (void)tmp;
         }
     }
     template<typename U, typename F>
@@ -287,11 +297,13 @@ struct result
         {
             auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(other.as_ok()));
             assert(tmp == std::addressof(this->succ));
+            (void)tmp;
         }
         else
         {
             auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(other.as_err()));
             assert(tmp == std::addressof(this->fail));
+            (void)tmp;
         }
     }
 
@@ -302,11 +314,13 @@ struct result
         {
             auto tmp = ::new(std::addressof(this->succ)) success_type(other.as_ok());
             assert(tmp == std::addressof(this->succ));
+            (void)tmp;
         }
         else
         {
             auto tmp = ::new(std::addressof(this->fail)) failure_type(other.as_err());
             assert(tmp == std::addressof(this->fail));
+            (void)tmp;
         }
         is_ok_ = other.is_ok();
         return *this;
@@ -318,11 +332,13 @@ struct result
         {
             auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(other.as_ok()));
             assert(tmp == std::addressof(this->succ));
+            (void)tmp;
         }
         else
         {
             auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(other.as_err()));
             assert(tmp == std::addressof(this->fail));
+            (void)tmp;
         }
         is_ok_ = other.is_ok();
         return *this;
@@ -336,11 +352,13 @@ struct result
         {
             auto tmp = ::new(std::addressof(this->succ)) success_type(other.as_ok());
             assert(tmp == std::addressof(this->succ));
+            (void)tmp;
         }
         else
         {
             auto tmp = ::new(std::addressof(this->fail)) failure_type(other.as_err());
             assert(tmp == std::addressof(this->fail));
+            (void)tmp;
         }
         is_ok_ = other.is_ok();
         return *this;
@@ -353,11 +371,13 @@ struct result
         {
             auto tmp = ::new(std::addressof(this->succ)) success_type(std::move(other.as_ok()));
             assert(tmp == std::addressof(this->succ));
+            (void)tmp;
         }
         else
         {
             auto tmp = ::new(std::addressof(this->fail)) failure_type(std::move(other.as_err()));
             assert(tmp == std::addressof(this->fail));
+            (void)tmp;
         }
         is_ok_ = other.is_ok();
         return *this;
@@ -441,21 +461,21 @@ struct result
     // F: T -> U
     // retval: result<U, E>
     template<typename F>
-    result<return_type_of_t<F, value_type&>, error_type>
+    result<detail::return_type_of_t<F, value_type&>, error_type>
     map(F&& f) &
     {
         if(this->is_ok()){return ok(f(this->as_ok()));}
         return err(this->as_err());
     }
     template<typename F>
-    result<return_type_of_t<F, value_type const&>, error_type>
+    result<detail::return_type_of_t<F, value_type const&>, error_type>
     map(F&& f) const&
     {
         if(this->is_ok()){return ok(f(this->as_ok()));}
         return err(this->as_err());
     }
     template<typename F>
-    result<return_type_of_t<F, value_type &&>, error_type>
+    result<detail::return_type_of_t<F, value_type &&>, error_type>
     map(F&& f) &&
     {
         if(this->is_ok()){return ok(f(std::move(this->as_ok())));}
@@ -466,21 +486,21 @@ struct result
     // F: E -> F
     // retval: result<T, F>
     template<typename F>
-    result<value_type, return_type_of_t<F, error_type&>>
+    result<value_type, detail::return_type_of_t<F, error_type&>>
     map_err(F&& f) &
     {
         if(this->is_err()){return err(f(this->as_err()));}
         return ok(this->as_ok());
     }
     template<typename F>
-    result<value_type, return_type_of_t<F, error_type const&>>
+    result<value_type, detail::return_type_of_t<F, error_type const&>>
     map_err(F&& f) const&
     {
         if(this->is_err()){return err(f(this->as_err()));}
         return ok(this->as_ok());
     }
     template<typename F>
-    result<value_type, return_type_of_t<F, error_type&&>>
+    result<value_type, detail::return_type_of_t<F, error_type&&>>
     map_err(F&& f) &&
     {
         if(this->is_err()){return err(f(std::move(this->as_err())));}
@@ -491,21 +511,21 @@ struct result
     // F: T -> U
     // retval: U
     template<typename F, typename U>
-    return_type_of_t<F, value_type&>
+    detail::return_type_of_t<F, value_type&>
     map_or_else(F&& f, U&& opt) &
     {
         if(this->is_err()){return std::forward<U>(opt);}
         return f(this->as_ok());
     }
     template<typename F, typename U>
-    return_type_of_t<F, value_type const&>
+    detail::return_type_of_t<F, value_type const&>
     map_or_else(F&& f, U&& opt) const&
     {
         if(this->is_err()){return std::forward<U>(opt);}
         return f(this->as_ok());
     }
     template<typename F, typename U>
-    return_type_of_t<F, value_type&&>
+    detail::return_type_of_t<F, value_type&&>
     map_or_else(F&& f, U&& opt) &&
     {
         if(this->is_err()){return std::forward<U>(opt);}
@@ -516,21 +536,21 @@ struct result
     // F: E -> U
     // retval: U
     template<typename F, typename U>
-    return_type_of_t<F, error_type&>
+    detail::return_type_of_t<F, error_type&>
     map_err_or_else(F&& f, U&& opt) &
     {
         if(this->is_ok()){return std::forward<U>(opt);}
         return f(this->as_err());
     }
     template<typename F, typename U>
-    return_type_of_t<F, error_type const&>
+    detail::return_type_of_t<F, error_type const&>
     map_err_or_else(F&& f, U&& opt) const&
     {
         if(this->is_ok()){return std::forward<U>(opt);}
         return f(this->as_err());
     }
     template<typename F, typename U>
-    return_type_of_t<F, error_type&&>
+    detail::return_type_of_t<F, error_type&&>
     map_err_or_else(F&& f, U&& opt) &&
     {
         if(this->is_ok()){return std::forward<U>(opt);}
@@ -542,21 +562,21 @@ struct result
     // toml::err(error_type) should be convertible to U.
     // normally, type U is another result<S, F> and E is convertible to F
     template<typename F>
-    return_type_of_t<F, value_type&>
+    detail::return_type_of_t<F, value_type&>
     and_then(F&& f) &
     {
         if(this->is_ok()){return f(this->as_ok());}
         return err(this->as_err());
     }
     template<typename F>
-    return_type_of_t<F, value_type const&>
+    detail::return_type_of_t<F, value_type const&>
     and_then(F&& f) const&
     {
         if(this->is_ok()){return f(this->as_ok());}
         return err(this->as_err());
     }
     template<typename F>
-    return_type_of_t<F, value_type&&>
+    detail::return_type_of_t<F, value_type&&>
     and_then(F&& f) &&
     {
         if(this->is_ok()){return f(std::move(this->as_ok()));}
@@ -568,21 +588,21 @@ struct result
     // toml::ok(value_type) should be convertible to U.
     // normally, type U is another result<S, F> and T is convertible to S
     template<typename F>
-    return_type_of_t<F, error_type&>
+    detail::return_type_of_t<F, error_type&>
     or_else(F&& f) &
     {
         if(this->is_err()){return f(this->as_err());}
         return ok(this->as_ok());
     }
     template<typename F>
-    return_type_of_t<F, error_type const&>
+    detail::return_type_of_t<F, error_type const&>
     or_else(F&& f) const&
     {
         if(this->is_err()){return f(this->as_err());}
         return ok(this->as_ok());
     }
     template<typename F>
-    return_type_of_t<F, error_type&&>
+    detail::return_type_of_t<F, error_type&&>
     or_else(F&& f) &&
     {
         if(this->is_err()){return f(std::move(this->as_err()));}
@@ -672,5 +692,26 @@ void swap(result<T, E>& lhs, result<T, E>& rhs)
 //     return lhs.is_ok() ? lhs : rhs;
 // }
 
+// ----------------------------------------------------------------------------
+// re-use result<T, E> as a optional<T> with none_t
+
+namespace detail
+{
+struct none_t {};
+inline bool operator==(const none_t&, const none_t&) noexcept {return true;}
+inline bool operator!=(const none_t&, const none_t&) noexcept {return false;}
+inline bool operator< (const none_t&, const none_t&) noexcept {return false;}
+inline bool operator<=(const none_t&, const none_t&) noexcept {return true;}
+inline bool operator> (const none_t&, const none_t&) noexcept {return false;}
+inline bool operator>=(const none_t&, const none_t&) noexcept {return true;}
+template<typename charT, typename traitsT>
+std::basic_ostream<charT, traitsT>&
+operator<<(std::basic_ostream<charT, traitsT>& os, const none_t&)
+{
+    os << "none";
+    return os;
+}
+inline failure<none_t> none() noexcept {return failure<none_t>{none_t{}};}
+} // detail
 } // toml11
 #endif// TOML11_RESULT_H

toml/serializer.hpp

@@ -0,0 +1,994 @@
+//     Copyright Toru Niina 2019.
+// Distributed under the MIT License.
+#ifndef TOML11_SERIALIZER_HPP
+#define TOML11_SERIALIZER_HPP
+#include <cmath>
+#include <cstdio>
+
+#include <limits>
+
+#if defined(_WIN32)
+#include <locale.h>
+#elif defined(__APPLE__) || defined(__FreeBSD__)
+#include <xlocale.h>
+#elif defined(__linux__)
+#include <locale.h>
+#endif
+
+#include "lexer.hpp"
+#include "value.hpp"
+
+namespace toml
+{
+
+// This function serialize a key. It checks a string is a bare key and
+// escapes special characters if the string is not compatible to a bare key.
+// ```cpp
+// std::string k("non.bare.key"); // the key itself includes `.`s.
+// std::string formatted = toml::format_key(k);
+// assert(formatted == "\"non.bare.key\"");
+// ```
+//
+// This function is exposed to make it easy to write a user-defined serializer.
+// Since toml restricts characters available in a bare key, generally a string
+// should be escaped. But checking whether a string needs to be surrounded by
+// a `"` and escaping some special character is boring.
+template<typename charT, typename traits, typename Alloc>
+std::basic_string<charT, traits, Alloc>
+format_key(const std::basic_string<charT, traits, Alloc>& k)
+{
+    if(k.empty())
+    {
+        return std::string("\"\"");
+    }
+
+    // check the key can be a bare (unquoted) key
+    detail::location loc(k, std::vector<char>(k.begin(), k.end()));
+    detail::lex_unquoted_key::invoke(loc);
+    if(loc.iter() == loc.end())
+    {
+        return k; // all the tokens are consumed. the key is unquoted-key.
+    }
+
+    //if it includes special characters, then format it in a "quoted" key.
+    std::basic_string<charT, traits, Alloc> serialized("\"");
+    for(const char c : k)
+    {
+        switch(c)
+        {
+            case '\\': {serialized += "\\\\"; break;}
+            case '\"': {serialized += "\\\""; break;}
+            case '\b': {serialized += "\\b";  break;}
+            case '\t': {serialized += "\\t";  break;}
+            case '\f': {serialized += "\\f";  break;}
+            case '\n': {serialized += "\\n";  break;}
+            case '\r': {serialized += "\\r";  break;}
+            default: {
+                if (c >= 0x00 && c < 0x20)
+                {
+                    std::array<char, 7> buf;
+                    std::snprintf(buf.data(), buf.size(), "\\u00%02x", static_cast<int>(c));
+                    serialized += buf.data();
+                }
+                else
+                {
+                    serialized += c;
+                }
+                break;
+            }
+        }
+    }
+    serialized += "\"";
+    return serialized;
+}
+
+template<typename charT, typename traits, typename Alloc>
+std::basic_string<charT, traits, Alloc>
+format_keys(const std::vector<std::basic_string<charT, traits, Alloc>>& keys)
+{
+    if(keys.empty())
+    {
+        return std::string("\"\"");
+    }
+
+    std::basic_string<charT, traits, Alloc> serialized;
+    for(const auto& ky : keys)
+    {
+        serialized += format_key(ky);
+        serialized += charT('.');
+    }
+    serialized.pop_back(); // remove the last dot '.'
+    return serialized;
+}
+
+template<typename Value>
+struct serializer
+{
+    static_assert(detail::is_basic_value<Value>::value,
+                  "toml::serializer is for toml::value and its variants, "
+                  "toml::basic_value<...>.");
+
+    using value_type           = Value;
+    using key_type             = typename value_type::key_type            ;
+    using comment_type         = typename value_type::comment_type        ;
+    using boolean_type         = typename value_type::boolean_type        ;
+    using integer_type         = typename value_type::integer_type        ;
+    using floating_type        = typename value_type::floating_type       ;
+    using string_type          = typename value_type::string_type         ;
+    using local_time_type      = typename value_type::local_time_type     ;
+    using local_date_type      = typename value_type::local_date_type     ;
+    using local_datetime_type  = typename value_type::local_datetime_type ;
+    using offset_datetime_type = typename value_type::offset_datetime_type;
+    using array_type           = typename value_type::array_type          ;
+    using table_type           = typename value_type::table_type          ;
+
+    serializer(const std::size_t w              = 80u,
+               const int         float_prec     = std::numeric_limits<toml::floating>::max_digits10,
+               const bool        can_be_inlined = false,
+               const bool        no_comment     = false,
+               std::vector<toml::key> ks        = {},
+               const bool     value_has_comment = false)
+        : can_be_inlined_(can_be_inlined), no_comment_(no_comment),
+          value_has_comment_(value_has_comment && !no_comment),
+          float_prec_(float_prec), width_(w), keys_(std::move(ks))
+    {}
+    ~serializer() = default;
+
+    std::string operator()(const boolean_type& b) const
+    {
+        return b ? "true" : "false";
+    }
+    std::string operator()(const integer_type i) const
+    {
+#if defined(_WIN32)
+        _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
+        const std::string original_locale(setlocale(LC_NUMERIC, nullptr));
+        setlocale(LC_NUMERIC, "C");
+#elif defined(__APPLE__) || defined(__FreeBSD__) || defined(__linux__)
+        const auto c_locale = newlocale(LC_NUMERIC_MASK, "C", locale_t(0));
+        locale_t original_locale(0);
+        if(c_locale != locale_t(0))
+        {
+            original_locale = uselocale(c_locale);
+        }
+#endif
+
+        const auto str = std::to_string(i);
+
+#if defined(_WIN32)
+        setlocale(LC_NUMERIC, original_locale.c_str());
+        _configthreadlocale(_DISABLE_PER_THREAD_LOCALE);
+#elif defined(__APPLE__) || defined(__FreeBSD__) || defined(__linux__)
+        if(original_locale != locale_t(0))
+        {
+            uselocale(original_locale);
+        }
+#endif
+        return str;
+    }
+    std::string operator()(const floating_type f) const
+    {
+        if(std::isnan(f))
+        {
+            if(std::signbit(f))
+            {
+                return std::string("-nan");
+            }
+            else
+            {
+                return std::string("nan");
+            }
+        }
+        else if(!std::isfinite(f))
+        {
+            if(std::signbit(f))
+            {
+                return std::string("-inf");
+            }
+            else
+            {
+                return std::string("inf");
+            }
+        }
+
+        // set locale to "C".
+        // To make it thread-local, we use OS-specific features.
+        // If we set process-global locale, it can break other thread that also
+        // outputs something simultaneously.
+#if defined(_WIN32)
+        _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
+        const std::string original_locale(setlocale(LC_NUMERIC, nullptr));
+        setlocale(LC_NUMERIC, "C");
+#elif defined(__APPLE__) || defined(__FreeBSD__) || defined(__linux__)
+        const auto c_locale = newlocale(LC_NUMERIC_MASK, "C", locale_t(0));
+        locale_t original_locale(0);
+        if(c_locale != locale_t(0))
+        {
+            original_locale = uselocale(c_locale);
+        }
+#endif
+
+        const auto fmt = "%.*g";
+        const auto bsz = std::snprintf(nullptr, 0, fmt, this->float_prec_, f);
+        // +1 for null character(\0)
+        std::vector<char> buf(static_cast<std::size_t>(bsz + 1), '\0');
+        std::snprintf(buf.data(), buf.size(), fmt, this->float_prec_, f);
+
+        // restore the original locale
+#if defined(_WIN32)
+        setlocale(LC_NUMERIC, original_locale.c_str());
+        _configthreadlocale(_DISABLE_PER_THREAD_LOCALE);
+#elif defined(__APPLE__) || defined(__FreeBSD__) || defined(__linux__)
+        if(original_locale != locale_t(0))
+        {
+            uselocale(original_locale);
+        }
+#endif
+
+        std::string token(buf.begin(), std::prev(buf.end()));
+        if(!token.empty() && token.back() == '.') // 1. => 1.0
+        {
+            token += '0';
+        }
+
+        const auto e = std::find_if(
+            token.cbegin(), token.cend(), [](const char c) noexcept -> bool {
+                return c == 'e' || c == 'E';
+            });
+        const auto has_exponent = (token.cend() != e);
+        const auto has_fraction = (token.cend() != std::find(
+            token.cbegin(), token.cend(), '.'));
+
+        if(!has_exponent && !has_fraction)
+        {
+            // the resulting value does not have any float specific part!
+            token += ".0";
+        }
+        return token;
+    }
+    std::string operator()(const string_type& s) const
+    {
+        if(s.kind == string_t::basic)
+        {
+            if((std::find(s.str.cbegin(), s.str.cend(), '\n') != s.str.cend() ||
+                std::find(s.str.cbegin(), s.str.cend(), '\"') != s.str.cend()) &&
+               this->width_ != (std::numeric_limits<std::size_t>::max)())
+            {
+                // if linefeed or double-quote is contained,
+                // make it multiline basic string.
+                const auto escaped = this->escape_ml_basic_string(s.str);
+                std::string open("\"\"\"");
+                std::string close("\"\"\"");
+                if(escaped.find('\n') != std::string::npos ||
+                   this->width_ < escaped.size() + 6)
+                {
+                    // if the string body contains newline or is enough long,
+                    // add newlines after and before delimiters.
+                    open += "\n";
+                    close = std::string("\\\n") + close;
+                }
+                return open + escaped + close;
+            }
+
+            // no linefeed. try to make it oneline-string.
+            std::string oneline = this->escape_basic_string(s.str);
+            if(oneline.size() + 2 < width_ || width_ < 2)
+            {
+                const std::string quote("\"");
+                return quote + oneline + quote;
+            }
+
+            // the line is too long compared to the specified width.
+            // split it into multiple lines.
+            std::string token("\"\"\"\n");
+            while(!oneline.empty())
+            {
+                if(oneline.size() < width_)
+                {
+                    token += oneline;
+                    oneline.clear();
+                }
+                else if(oneline.at(width_-2) == '\\')
+                {
+                    token += oneline.substr(0, width_-2);
+                    token += "\\\n";
+                    oneline.erase(0, width_-2);
+                }
+                else
+                {
+                    token += oneline.substr(0, width_-1);
+                    token += "\\\n";
+                    oneline.erase(0, width_-1);
+                }
+            }
+            return token + std::string("\\\n\"\"\"");
+        }
+        else // the string `s` is literal-string.
+        {
+            if(std::find(s.str.cbegin(), s.str.cend(), '\n') != s.str.cend() ||
+               std::find(s.str.cbegin(), s.str.cend(), '\'') != s.str.cend() )
+            {
+                std::string open("'''");
+                if(this->width_ + 6 < s.str.size())
+                {
+                    open += '\n'; // the first newline is ignored by TOML spec
+                }
+                const std::string close("'''");
+                return open + s.str + close;
+            }
+            else
+            {
+                const std::string quote("'");
+                return quote + s.str + quote;
+            }
+        }
+    }
+
+    std::string operator()(const local_date_type& d) const
+    {
+        std::ostringstream oss;
+        oss << d;
+        return oss.str();
+    }
+    std::string operator()(const local_time_type& t) const
+    {
+        std::ostringstream oss;
+        oss << t;
+        return oss.str();
+    }
+    std::string operator()(const local_datetime_type& dt) const
+    {
+        std::ostringstream oss;
+        oss << dt;
+        return oss.str();
+    }
+    std::string operator()(const offset_datetime_type& odt) const
+    {
+        std::ostringstream oss;
+        oss << odt;
+        return oss.str();
+    }
+
+    std::string operator()(const array_type& v) const
+    {
+        if(v.empty())
+        {
+            return std::string("[]");
+        }
+        if(this->is_array_of_tables(v))
+        {
+            return make_array_of_tables(v);
+        }
+
+        // not an array of tables. normal array.
+        // first, try to make it inline if none of the elements have a comment.
+        if( ! this->has_comment_inside(v))
+        {
+            const auto inl = this->make_inline_array(v);
+            if(inl.size() < this->width_ &&
+               std::find(inl.cbegin(), inl.cend(), '\n') == inl.cend())
+            {
+                return inl;
+            }
+        }
+
+        // if the length exceeds this->width_, print multiline array.
+        // key = [
+        //   # ...
+        //   42,
+        //   ...
+        // ]
+        std::string token;
+        std::string current_line;
+        token += "[\n";
+        for(const auto& item : v)
+        {
+            if( ! item.comments().empty() && !no_comment_)
+            {
+                // if comment exists, the element must be the only element in the line.
+                // e.g. the following is not allowed.
+                // ```toml
+                // array = [
+                // # comment for what?
+                // 1, 2, 3, 4, 5
+                // ]
+                // ```
+                if(!current_line.empty())
+                {
+                    if(current_line.back() != '\n')
+                    {
+                        current_line += '\n';
+                    }
+                    token += current_line;
+                    current_line.clear();
+                }
+                for(const auto& c : item.comments())
+                {
+                    token += '#';
+                    token += c;
+                    token += '\n';
+                }
+                token += toml::visit(*this, item);
+                if(!token.empty() && token.back() == '\n') {token.pop_back();}
+                token += ",\n";
+                continue;
+            }
+            std::string next_elem;
+            if(item.is_table())
+            {
+                serializer ser(*this);
+                ser.can_be_inlined_ = true;
+                ser.width_ = (std::numeric_limits<std::size_t>::max)();
+                next_elem += toml::visit(ser, item);
+            }
+            else
+            {
+                next_elem += toml::visit(*this, item);
+            }
+
+            // comma before newline.
+            if(!next_elem.empty() && next_elem.back() == '\n') {next_elem.pop_back();}
+
+            // if current line does not exceeds the width limit, continue.
+            if(current_line.size() + next_elem.size() + 1 < this->width_)
+            {
+                current_line += next_elem;
+                current_line += ',';
+            }
+            else if(current_line.empty())
+            {
+                // if current line was empty, force put the next_elem because
+                // next_elem is not splittable
+                token += next_elem;
+                token += ",\n";
+                // current_line is kept empty
+            }
+            else // reset current_line
+            {
+                assert(current_line.back() == ',');
+                token += current_line;
+                token += '\n';
+                current_line = next_elem;
+                current_line += ',';
+            }
+        }
+        if(!current_line.empty())
+        {
+            if(!current_line.empty() && current_line.back() != '\n')
+            {
+                current_line += '\n';
+            }
+            token += current_line;
+        }
+        token += "]\n";
+        return token;
+    }
+
+    // templatize for any table-like container
+    std::string operator()(const table_type& v) const
+    {
+        // if an element has a comment, then it can't be inlined.
+        // table = {# how can we write a comment for this? key = "value"}
+        if(this->can_be_inlined_ && !(this->has_comment_inside(v)))
+        {
+            std::string token;
+            if(!this->keys_.empty())
+            {
+                token += format_key(this->keys_.back());
+                token += " = ";
+            }
+            token += this->make_inline_table(v);
+            if(token.size() < this->width_ &&
+               token.end() == std::find(token.begin(), token.end(), '\n'))
+            {
+                return token;
+            }
+        }
+
+        std::string token;
+        if(!keys_.empty())
+        {
+            token += '[';
+            token += format_keys(keys_);
+            token += "]\n";
+        }
+        token += this->make_multiline_table(v);
+        return token;
+    }
+
+  private:
+
+    std::string escape_basic_string(const std::string& s) const
+    {
+        //XXX assuming `s` is a valid utf-8 sequence.
+        std::string retval;
+        for(const char c : s)
+        {
+            switch(c)
+            {
+                case '\\': {retval += "\\\\"; break;}
+                case '\"': {retval += "\\\""; break;}
+                case '\b': {retval += "\\b";  break;}
+                case '\t': {retval += "\\t";  break;}
+                case '\f': {retval += "\\f";  break;}
+                case '\n': {retval += "\\n";  break;}
+                case '\r': {retval += "\\r";  break;}
+                default  :
+                {
+                    if((0x00 <= c && c <= 0x08) || (0x0A <= c && c <= 0x1F) || c == 0x7F)
+                    {
+                        retval += "\\u00";
+                        retval += char(48 + (c / 16));
+                        retval += char((c % 16 < 10 ? 48 : 55) + (c % 16));
+                    }
+                    else
+                    {
+                        retval += c;
+                    }
+                }
+            }
+        }
+        return retval;
+    }
+
+    std::string escape_ml_basic_string(const std::string& s) const
+    {
+        std::string retval;
+        for(auto i=s.cbegin(), e=s.cend(); i!=e; ++i)
+        {
+            switch(*i)
+            {
+                case '\\': {retval += "\\\\"; break;}
+                // One or two consecutive "s are allowed.
+                // Later we will check there are no three consecutive "s.
+                //   case '\"': {retval += "\\\""; break;}
+                case '\b': {retval += "\\b";  break;}
+                case '\t': {retval += "\\t";  break;}
+                case '\f': {retval += "\\f";  break;}
+                case '\n': {retval += "\n";   break;}
+                case '\r':
+                {
+                    if(std::next(i) != e && *std::next(i) == '\n')
+                    {
+                        retval += "\r\n";
+                        ++i;
+                    }
+                    else
+                    {
+                        retval += "\\r";
+                    }
+                    break;
+                }
+                default  :
+                {
+                    const auto c = *i;
+                    if((0x00 <= c && c <= 0x08) || (0x0A <= c && c <= 0x1F) || c == 0x7F)
+                    {
+                        retval += "\\u00";
+                        retval += char(48 + (c / 16));
+                        retval += char((c % 16 < 10 ? 48 : 55) + (c % 16));
+                    }
+                    else
+                    {
+                        retval += c;
+                    }
+                }
+
+            }
+        }
+        // Only 1 or 2 consecutive `"`s are allowed in multiline basic string.
+        // 3 consecutive `"`s are considered as a closing delimiter.
+        // We need to check if there are 3 or more consecutive `"`s and insert
+        // backslash to break them down into several short `"`s like the `str6`
+        // in the following example.
+        // ```toml
+        // str4 = """Here are two quotation marks: "". Simple enough."""
+        // # str5 = """Here are three quotation marks: """."""  # INVALID
+        // str5 = """Here are three quotation marks: ""\"."""
+        // str6 = """Here are fifteen quotation marks: ""\"""\"""\"""\"""\"."""
+        // ```
+        auto found_3_quotes = retval.find("\"\"\"");
+        while(found_3_quotes != std::string::npos)
+        {
+            retval.replace(found_3_quotes, 3, "\"\"\\\"");
+            found_3_quotes = retval.find("\"\"\"");
+        }
+        return retval;
+    }
+
+    // if an element of a table or an array has a comment, it cannot be inlined.
+    bool has_comment_inside(const array_type& a) const noexcept
+    {
+        // if no_comment is set, comments would not be written.
+        if(this->no_comment_) {return false;}
+
+        for(const auto& v : a)
+        {
+            if(!v.comments().empty()) {return true;}
+        }
+        return false;
+    }
+    bool has_comment_inside(const table_type& t) const noexcept
+    {
+        // if no_comment is set, comments would not be written.
+        if(this->no_comment_) {return false;}
+
+        for(const auto& kv : t)
+        {
+            if(!kv.second.comments().empty()) {return true;}
+        }
+        return false;
+    }
+
+    std::string make_inline_array(const array_type& v) const
+    {
+        assert(!has_comment_inside(v));
+        std::string token;
+        token += '[';
+        bool is_first = true;
+        for(const auto& item : v)
+        {
+            if(is_first) {is_first = false;} else {token += ',';}
+            token += visit(serializer(
+                (std::numeric_limits<std::size_t>::max)(), this->float_prec_,
+                /* inlined */ true, /*no comment*/ false, /*keys*/ {},
+                /*has_comment*/ !item.comments().empty()), item);
+        }
+        token += ']';
+        return token;
+    }
+
+    std::string make_inline_table(const table_type& v) const
+    {
+        assert(!has_comment_inside(v));
+        assert(this->can_be_inlined_);
+        std::string token;
+        token += '{';
+        bool is_first = true;
+        for(const auto& kv : v)
+        {
+            // in inline tables, trailing comma is not allowed (toml-lang #569).
+            if(is_first) {is_first = false;} else {token += ',';}
+            token += format_key(kv.first);
+            token += '=';
+            token += visit(serializer(
+                (std::numeric_limits<std::size_t>::max)(), this->float_prec_,
+                /* inlined */ true, /*no comment*/ false, /*keys*/ {},
+                /*has_comment*/ !kv.second.comments().empty()), kv.second);
+        }
+        token += '}';
+        return token;
+    }
+
+    std::string make_multiline_table(const table_type& v) const
+    {
+        std::string token;
+
+        // print non-table elements first.
+        // ```toml
+        // [foo]         # a table we're writing now here
+        // key = "value" # <- non-table element, "key"
+        // # ...
+        // [foo.bar] # <- table element, "bar"
+        // ```
+        // because after printing [foo.bar], the remaining non-table values will
+        // be assigned into [foo.bar], not [foo]. Those values should be printed
+        // earlier.
+        for(const auto& kv : v)
+        {
+            if(kv.second.is_table() || is_array_of_tables(kv.second))
+            {
+                continue;
+            }
+
+            token += write_comments(kv.second);
+
+            const auto key_and_sep    = format_key(kv.first) + " = ";
+            const auto residual_width = (this->width_ > key_and_sep.size()) ?
+                                        this->width_ - key_and_sep.size() : 0;
+            token += key_and_sep;
+            token += visit(serializer(residual_width, this->float_prec_,
+                /*can be inlined*/ true, /*no comment*/ false, /*keys*/ {},
+                /*has_comment*/ !kv.second.comments().empty()), kv.second);
+
+            if(token.back() != '\n')
+            {
+                token += '\n';
+            }
+        }
+
+        // normal tables / array of tables
+
+        // after multiline table appeared, the other tables cannot be inline
+        // because the table would be assigned into the table.
+        // [foo]
+        // ...
+        // bar = {...} # <- bar will be a member of [foo].
+        bool multiline_table_printed = false;
+        for(const auto& kv : v)
+        {
+            if(!kv.second.is_table() && !is_array_of_tables(kv.second))
+            {
+                continue; // other stuff are already serialized. skip them.
+            }
+
+            std::vector<toml::key> ks(this->keys_);
+            ks.push_back(kv.first);
+
+            auto tmp = visit(serializer(this->width_, this->float_prec_,
+                !multiline_table_printed, this->no_comment_, ks,
+                /*has_comment*/ !kv.second.comments().empty()), kv.second);
+
+            // If it is the first time to print a multi-line table, it would be
+            // helpful to separate normal key-value pair and subtables by a
+            // newline.
+            // (this checks if the current key-value pair contains newlines.
+            //  but it is not perfect because multi-line string can also contain
+            //  a newline. in such a case, an empty line will be written) TODO
+            if((!multiline_table_printed) &&
+               std::find(tmp.cbegin(), tmp.cend(), '\n') != tmp.cend())
+            {
+                multiline_table_printed = true;
+                token += '\n'; // separate key-value pairs and subtables
+
+                token += write_comments(kv.second);
+                token += tmp;
+
+                // care about recursive tables (all tables in each level prints
+                // newline and there will be a full of newlines)
+                if(tmp.substr(tmp.size() - 2, 2) != "\n\n" &&
+                   tmp.substr(tmp.size() - 4, 4) != "\r\n\r\n" )
+                {
+                    token += '\n';
+                }
+            }
+            else
+            {
+                token += write_comments(kv.second);
+                token += tmp;
+                token += '\n';
+            }
+        }
+        return token;
+    }
+
+    std::string make_array_of_tables(const array_type& v) const
+    {
+        // if it's not inlined, we need to add `[[table.key]]`.
+        // but if it can be inlined, we can format it as the following.
+        // ```
+        // table.key = [
+        //   {...},
+        //   # comment
+        //   {...},
+        // ]
+        // ```
+        // This function checks if inlinization is possible or not, and then
+        // format the array-of-tables in a proper way.
+        //
+        // Note about comments:
+        //
+        // If the array itself has a comment (value_has_comment_ == true), we
+        // should try to make it inline.
+        // ```toml
+        // # comment about array
+        // array = [
+        //   # comment about table element
+        //   {of = "table"}
+        // ]
+        // ```
+        // If it is formatted as a multiline table, the two comments becomes
+        // indistinguishable.
+        // ```toml
+        // # comment about array
+        // # comment about table element
+        // [[array]]
+        // of = "table"
+        // ```
+        // So we need to try to make it inline, and it force-inlines regardless
+        // of the line width limit.
+        //     It may fail if the element of a table has comment. In that case,
+        // the array-of-tables will be formatted as a multiline table.
+        if(this->can_be_inlined_ || this->value_has_comment_)
+        {
+            std::string token;
+            if(!keys_.empty())
+            {
+                token += format_key(keys_.back());
+                token += " = ";
+            }
+
+            bool failed = false;
+            token += "[\n";
+            for(const auto& item : v)
+            {
+                // if an element of the table has a comment, the table
+                // cannot be inlined.
+                if(this->has_comment_inside(item.as_table()))
+                {
+                    failed = true;
+                    break;
+                }
+                // write comments for the table itself
+                token += write_comments(item);
+
+                const auto t = this->make_inline_table(item.as_table());
+
+                if(t.size() + 1 > width_ || // +1 for the last comma {...},
+                   std::find(t.cbegin(), t.cend(), '\n') != t.cend())
+                {
+                    // if the value itself has a comment, ignore the line width limit
+                    if( ! this->value_has_comment_)
+                    {
+                        failed = true;
+                        break;
+                    }
+                }
+                token += t;
+                token += ",\n";
+            }
+
+            if( ! failed)
+            {
+                token += "]\n";
+                return token;
+            }
+            // if failed, serialize them as [[array.of.tables]].
+        }
+
+        std::string token;
+        for(const auto& item : v)
+        {
+            token += write_comments(item);
+            token += "[[";
+            token += format_keys(keys_);
+            token += "]]\n";
+            token += this->make_multiline_table(item.as_table());
+        }
+        return token;
+    }
+
+    std::string write_comments(const value_type& v) const
+    {
+        std::string retval;
+        if(this->no_comment_) {return retval;}
+
+        for(const auto& c : v.comments())
+        {
+            retval += '#';
+            retval += c;
+            retval += '\n';
+        }
+        return retval;
+    }
+
+    bool is_array_of_tables(const value_type& v) const
+    {
+        if(!v.is_array() || v.as_array().empty()) {return false;}
+        return is_array_of_tables(v.as_array());
+    }
+    bool is_array_of_tables(const array_type& v) const
+    {
+        // Since TOML v0.5.0, heterogeneous arrays are allowed. So we need to
+        // check all the element in an array to check if the array is an array
+        // of tables.
+        return std::all_of(v.begin(), v.end(), [](const value_type& elem) {
+                return elem.is_table();
+            });
+    }
+
+  private:
+
+    bool        can_be_inlined_;
+    bool        no_comment_;
+    bool        value_has_comment_;
+    int         float_prec_;
+    std::size_t width_;
+    std::vector<toml::key> keys_;
+};
+
+template<typename C,
+         template<typename ...> class M, template<typename ...> class V>
+std::string
+format(const basic_value<C, M, V>& v, std::size_t w = 80u,
+       int fprec = std::numeric_limits<toml::floating>::max_digits10,
+       bool no_comment = false, bool force_inline = false)
+{
+    using value_type = basic_value<C, M, V>;
+    // if value is a table, it is considered to be a root object.
+    // the root object can't be an inline table.
+    if(v.is_table())
+    {
+        std::ostringstream oss;
+        if(!v.comments().empty())
+        {
+            oss << v.comments();
+            oss << '\n'; // to split the file comment from the first element
+        }
+        const auto serialized = visit(serializer<value_type>(w, fprec, false, no_comment), v);
+        oss << serialized;
+        return oss.str();
+    }
+    return visit(serializer<value_type>(w, fprec, force_inline), v);
+}
+
+namespace detail
+{
+template<typename charT, typename traits>
+int comment_index(std::basic_ostream<charT, traits>&)
+{
+    static const int index = std::ios_base::xalloc();
+    return index;
+}
+} // detail
+
+template<typename charT, typename traits>
+std::basic_ostream<charT, traits>&
+nocomment(std::basic_ostream<charT, traits>& os)
+{
+    // by default, it is zero. and by default, it shows comments.
+    os.iword(detail::comment_index(os)) = 1;
+    return os;
+}
+
+template<typename charT, typename traits>
+std::basic_ostream<charT, traits>&
+showcomment(std::basic_ostream<charT, traits>& os)
+{
+    // by default, it is zero. and by default, it shows comments.
+    os.iword(detail::comment_index(os)) = 0;
+    return os;
+}
+
+template<typename charT, typename traits, typename C,
+         template<typename ...> class M, template<typename ...> class V>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os, const basic_value<C, M, V>& v)
+{
+    using value_type = basic_value<C, M, V>;
+
+    // get status of std::setw().
+    const auto w     = static_cast<std::size_t>(os.width());
+    const int  fprec = static_cast<int>(os.precision());
+    os.width(0);
+
+    // by default, iword is initialized by 0. And by default, toml11 outputs
+    // comments. So `0` means showcomment. 1 means nocommnet.
+    const bool no_comment = (1 == os.iword(detail::comment_index(os)));
+
+    if(!no_comment && v.is_table() && !v.comments().empty())
+    {
+        os << v.comments();
+        os << '\n'; // to split the file comment from the first element
+    }
+    // the root object can't be an inline table. so pass `false`.
+    const auto serialized = visit(serializer<value_type>(w, fprec, no_comment, false), v);
+    os << serialized;
+
+    // if v is a non-table value, and has only one comment, then
+    // put a comment just after a value. in the following way.
+    //
+    // ```toml
+    // key = "value" # comment.
+    // ```
+    //
+    // Since the top-level toml object is a table, one who want to put a
+    // non-table toml value must use this in a following way.
+    //
+    // ```cpp
+    // toml::value v;
+    // std::cout << "user-defined-key = " << v << std::endl;
+    // ```
+    //
+    // In this case, it is impossible to put comments before key-value pair.
+    // The only way to preserve comments is to put all of them after a value.
+    if(!no_comment && !v.is_table() && !v.comments().empty())
+    {
+        os << " #";
+        for(const auto& c : v.comments()) {os << c;}
+    }
+    return os;
+}
+
+} // toml
+#endif// TOML11_SERIALIZER_HPP

toml/source_location.hpp

@@ -0,0 +1,239 @@
+//     Copyright Toru Niina 2019.
+// Distributed under the MIT License.
+#ifndef TOML11_SOURCE_LOCATION_HPP
+#define TOML11_SOURCE_LOCATION_HPP
+#include <cstdint>
+#include <sstream>
+
+#include "region.hpp"
+
+namespace toml
+{
+
+// A struct to contain location in a toml file.
+// The interface imitates std::experimental::source_location,
+// but not completely the same.
+//
+// It would be constructed by toml::value. It can be used to generate
+// user-defined error messages.
+//
+// - std::uint_least32_t line() const noexcept
+//   - returns the line number where the region is on.
+// - std::uint_least32_t column() const noexcept
+//   - returns the column number where the region starts.
+// - std::uint_least32_t region() const noexcept
+//   - returns the size of the region.
+//
+// +-- line()       +-- region of interest (region() == 9)
+// v            .---+---.
+// 12 | value = "foo bar"
+//              ^
+//              +-- column()
+//
+// - std::string const& file_name() const noexcept;
+//   - name of the file.
+// - std::string const& line_str() const noexcept;
+//   - the whole line that contains the region of interest.
+//
+struct source_location
+{
+  public:
+
+    source_location()
+        : line_num_(1), column_num_(1), region_size_(1),
+          file_name_("unknown file"), line_str_("")
+    {}
+
+    explicit source_location(const detail::region_base* reg)
+        : line_num_(1), column_num_(1), region_size_(1),
+          file_name_("unknown file"), line_str_("")
+    {
+        if(reg)
+        {
+            if(reg->line_num() != detail::region_base().line_num())
+            {
+                line_num_ = static_cast<std::uint_least32_t>(
+                        std::stoul(reg->line_num()));
+            }
+            column_num_  = static_cast<std::uint_least32_t>(reg->before() + 1);
+            region_size_ = static_cast<std::uint_least32_t>(reg->size());
+            file_name_   = reg->name();
+            line_str_    = reg->line();
+        }
+    }
+
+    explicit source_location(const detail::region& reg)
+        : line_num_(static_cast<std::uint_least32_t>(std::stoul(reg.line_num()))),
+          column_num_(static_cast<std::uint_least32_t>(reg.before() + 1)),
+          region_size_(static_cast<std::uint_least32_t>(reg.size())),
+          file_name_(reg.name()),
+          line_str_ (reg.line())
+    {}
+    explicit source_location(const detail::location& loc)
+        : line_num_(static_cast<std::uint_least32_t>(std::stoul(loc.line_num()))),
+          column_num_(static_cast<std::uint_least32_t>(loc.before() + 1)),
+          region_size_(static_cast<std::uint_least32_t>(loc.size())),
+          file_name_(loc.name()),
+          line_str_ (loc.line())
+    {}
+
+    ~source_location() = default;
+    source_location(source_location const&) = default;
+    source_location(source_location &&)     = default;
+    source_location& operator=(source_location const&) = default;
+    source_location& operator=(source_location &&)     = default;
+
+    std::uint_least32_t line()      const noexcept {return line_num_;}
+    std::uint_least32_t column()    const noexcept {return column_num_;}
+    std::uint_least32_t region()    const noexcept {return region_size_;}
+
+    std::string const&  file_name() const noexcept {return file_name_;}
+    std::string const&  line_str()  const noexcept {return line_str_;}
+
+  private:
+
+    std::uint_least32_t line_num_;
+    std::uint_least32_t column_num_;
+    std::uint_least32_t region_size_;
+    std::string         file_name_;
+    std::string         line_str_;
+};
+
+namespace detail
+{
+
+// internal error message generation.
+inline std::string format_underline(const std::string& message,
+        const std::vector<std::pair<source_location, std::string>>& loc_com,
+        const std::vector<std::string>& helps = {},
+        const bool colorize = TOML11_ERROR_MESSAGE_COLORIZED)
+{
+    std::size_t line_num_width = 0;
+    for(const auto& lc : loc_com)
+    {
+        std::uint_least32_t line = lc.first.line();
+        std::size_t        digit = 0;
+        while(line != 0)
+        {
+            line  /= 10;
+            digit +=  1;
+        }
+        line_num_width = (std::max)(line_num_width, digit);
+    }
+    // 1 is the minimum width
+    line_num_width = std::max<std::size_t>(line_num_width, 1);
+
+    std::ostringstream retval;
+
+    if(color::should_color() || colorize)
+    {
+        retval << color::colorize; // turn on ANSI color
+    }
+
+    // XXX
+    // Here, before `colorize` support, it does not output `[error]` prefix
+    // automatically. So some user may output it manually and this change may
+    // duplicate the prefix. To avoid it, check the first 7 characters and
+    // if it is "[error]", it removes that part from the message shown.
+    if(message.size() > 7 && message.substr(0, 7) == "[error]")
+    {
+        retval
+#ifndef TOML11_NO_ERROR_PREFIX
+               << color::bold << color::red << "[error]" << color::reset
+#endif
+               << color::bold << message.substr(7) << color::reset << '\n';
+    }
+    else
+    {
+        retval
+#ifndef TOML11_NO_ERROR_PREFIX
+               << color::bold << color::red << "[error] " << color::reset
+#endif
+               << color::bold << message << color::reset << '\n';
+    }
+
+    const auto format_one_location = [line_num_width]
+        (std::ostringstream& oss,
+         const source_location& loc, const std::string& comment) -> void
+        {
+            oss << ' ' << color::bold << color::blue
+                << std::setw(static_cast<int>(line_num_width))
+                << std::right << loc.line() << " | "  << color::reset
+                << loc.line_str() << '\n';
+
+            oss << make_string(line_num_width + 1, ' ')
+                << color::bold << color::blue << " | " << color::reset
+                << make_string(loc.column()-1 /*1-origin*/, ' ');
+
+            if(loc.region() == 1)
+            {
+                // invalid
+                // ^------
+                oss << color::bold << color::red << "^---" << color::reset;
+            }
+            else
+            {
+                // invalid
+                // ~~~~~~~
+                const auto underline_len = (std::min)(
+                    static_cast<std::size_t>(loc.region()), loc.line_str().size());
+                oss << color::bold << color::red
+                    << make_string(underline_len, '~') << color::reset;
+            }
+            oss << ' ';
+            oss << comment;
+            return;
+        };
+
+    assert(!loc_com.empty());
+
+    // --> example.toml
+    //   |
+    retval << color::bold << color::blue << " --> " << color::reset
+           << loc_com.front().first.file_name() << '\n';
+    retval << make_string(line_num_width + 1, ' ')
+           << color::bold << color::blue << " |\n"  << color::reset;
+    // 1 | key value
+    //   |    ^--- missing =
+    format_one_location(retval, loc_com.front().first, loc_com.front().second);
+
+    // process the rest of the locations
+    for(std::size_t i=1; i<loc_com.size(); ++i)
+    {
+        const auto& prev = loc_com.at(i-1);
+        const auto& curr = loc_com.at(i);
+
+        retval << '\n';
+        // if the filenames are the same, print "..."
+        if(prev.first.file_name() == curr.first.file_name())
+        {
+            retval << color::bold << color::blue << " ...\n" << color::reset;
+        }
+        else // if filename differs, print " --> filename.toml" again
+        {
+            retval << color::bold << color::blue << " --> " << color::reset
+                   << curr.first.file_name() << '\n';
+            retval << make_string(line_num_width + 1, ' ')
+                   << color::bold << color::blue << " |\n"  << color::reset;
+        }
+
+        format_one_location(retval, curr.first, curr.second);
+    }
+
+    if(!helps.empty())
+    {
+        retval << '\n';
+        retval << make_string(line_num_width + 1, ' ');
+        retval << color::bold << color::blue << " |" << color::reset;
+        for(const auto& help : helps)
+        {
+            retval << color::bold << "\nHint: " << color::reset;
+            retval << help;
+        }
+    }
+    return retval.str();
+}
+
+} // detail
+} // toml
+#endif// TOML11_SOURCE_LOCATION_HPP

toml/storage.hpp

@@ -16,10 +16,9 @@ struct storage
 {
     using value_type = T;
 
-    storage(value_type const& v): ptr(toml::make_unique<T>(v)) {}
-    storage(value_type&&      v): ptr(toml::make_unique<T>(std::move(v))) {}
+    explicit storage(value_type const& v): ptr(toml::make_unique<T>(v)) {}
+    explicit storage(value_type&&      v): ptr(toml::make_unique<T>(std::move(v))) {}
     ~storage() = default;
-
     storage(const storage& rhs): ptr(toml::make_unique<T>(*rhs.ptr)) {}
     storage& operator=(const storage& rhs)
     {

toml/string.hpp

@@ -1,10 +1,22 @@
 //     Copyright Toru Niina 2017.
 // Distributed under the MIT License.
-#ifndef TOML11_STRING_H
-#define TOML11_STRING_H
-#include <string>
+#ifndef TOML11_STRING_HPP
+#define TOML11_STRING_HPP
+
+#include "version.hpp"
+
 #include <cstdint>
 
+#include <algorithm>
+#include <string>
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+#if __has_include(<string_view>)
+#define TOML11_USING_STRING_VIEW 1
+#include <string_view>
+#endif
+#endif
+
 namespace toml
 {
 
@@ -40,6 +52,24 @@ struct string
     operator std::string const& () const& noexcept {return str;}
     operator std::string&&      () &&     noexcept {return std::move(str);}
 
+    string& operator+=(const char*        rhs) {str += rhs; return *this;}
+    string& operator+=(const char         rhs) {str += rhs; return *this;}
+    string& operator+=(const std::string& rhs) {str += rhs; return *this;}
+    string& operator+=(const string&      rhs) {str += rhs.str; return *this;}
+
+#if defined(TOML11_USING_STRING_VIEW) && TOML11_USING_STRING_VIEW>0
+    explicit string(std::string_view s): kind(string_t::basic), str(s){}
+    string(std::string_view s, string_t k): kind(k), str(s){}
+
+    string& operator=(std::string_view s)
+    {kind = string_t::basic; str = s; return *this;}
+
+    explicit operator std::string_view() const noexcept
+    {return std::string_view(str);}
+
+    string& operator+=(const std::string_view& rhs) {str += rhs; return *this;}
+#endif
+
     string_t    kind;
     std::string str;
 };
@@ -123,9 +153,74 @@ operator>=(const char* lhs, const string& rhs) {return std::string(lhs) >= rhs.s
 
 template<typename charT, typename traits>
 std::basic_ostream<charT, traits>&
-operator<<(std::basic_ostream<charT, traits>& os, const string& str)
+operator<<(std::basic_ostream<charT, traits>& os, const string& s)
 {
-    os << str.str;
+    if(s.kind == string_t::basic)
+    {
+        if(std::find(s.str.cbegin(), s.str.cend(), '\n') != s.str.cend())
+        {
+            // it contains newline. make it multiline string.
+            os << "\"\"\"\n";
+            for(auto i=s.str.cbegin(), e=s.str.cend(); i!=e; ++i)
+            {
+                switch(*i)
+                {
+                    case '\\': {os << "\\\\"; break;}
+                    case '\"': {os << "\\\""; break;}
+                    case '\b': {os << "\\b";  break;}
+                    case '\t': {os << "\\t";  break;}
+                    case '\f': {os << "\\f";  break;}
+                    case '\n': {os << '\n';   break;}
+                    case '\r':
+                    {
+                        // since it is a multiline string,
+                        // CRLF is not needed to be escaped.
+                        if(std::next(i) != e && *std::next(i) == '\n')
+                        {
+                            os << "\r\n";
+                            ++i;
+                        }
+                        else
+                        {
+                            os << "\\r";
+                        }
+                        break;
+                    }
+                    default: {os << *i; break;}
+                }
+            }
+            os << "\\\n\"\"\"";
+            return os;
+        }
+        // no newline. make it inline.
+        os << "\"";
+        for(const auto c : s.str)
+        {
+            switch(c)
+            {
+                case '\\': {os << "\\\\"; break;}
+                case '\"': {os << "\\\""; break;}
+                case '\b': {os << "\\b";  break;}
+                case '\t': {os << "\\t";  break;}
+                case '\f': {os << "\\f";  break;}
+                case '\n': {os << "\\n";  break;}
+                case '\r': {os << "\\r";  break;}
+                default  : {os << c;      break;}
+            }
+        }
+        os << "\"";
+        return os;
+    }
+    // the string `s` is literal-string.
+    if(std::find(s.str.cbegin(), s.str.cend(), '\n') != s.str.cend() ||
+       std::find(s.str.cbegin(), s.str.cend(), '\'') != s.str.cend() )
+    {
+        // contains newline or single quote. make it multiline.
+        os << "'''\n" << s.str << "'''";
+        return os;
+    }
+    // normal literal string
+    os << '\'' << s.str << '\'';
     return os;
 }
 

toml/to_toml.hpp

@@ -1,43 +0,0 @@
-//     Copyright Toru Niina 2017.
-// Distributed under the MIT License.
-#ifndef TOML11_TO_TOML
-#define TOML11_TO_TOML
-#include "value.hpp"
-
-namespace toml
-{
-
-template<typename T>
-inline value to_toml(T&& x)
-{
-    return value(std::forward<T>(x));
-}
-
-template<typename T>
-inline value to_toml(T&& x, string_t kind)
-{
-    return value(std::forward<T>(x), kind);
-}
-
-inline value to_toml(local_date d, local_time t)
-{
-    return value(local_datetime(d, t));
-}
-inline value to_toml(local_date d, local_time t, time_offset ofs)
-{
-    return value(offset_datetime(d, t, ofs));
-}
-
-template<typename ... Ts>
-inline value to_toml(Ts&& ... xs)
-{
-    return value(toml::array{toml::value(std::forward<Ts>(xs)) ... });
-}
-
-inline value to_toml(std::initializer_list<std::pair<std::string, toml::value>> xs)
-{
-    return value(toml::table(xs.begin(), xs.end()));
-}
-
-} // toml
-#endif // TOML11_TO_TOML

toml/traits.hpp

@@ -1,19 +1,34 @@
 //     Copyright Toru Niina 2017.
 // Distributed under the MIT License.
-#ifndef TOML11_TRAITS
-#define TOML11_TRAITS
+#ifndef TOML11_TRAITS_HPP
+#define TOML11_TRAITS_HPP
+
+#include "from.hpp"
+#include "into.hpp"
+#include "version.hpp"
+
+#include <chrono>
+#include <forward_list>
+#include <string>
+#include <tuple>
 #include <type_traits>
 #include <utility>
-#include <chrono>
-#include <tuple>
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+#if __has_include(<string_view>)
+#include <string_view>
+#endif // has_include(<string_view>)
+#endif // cplusplus   >= C++17
 
 namespace toml
 {
+template<typename C, template<typename ...> class T, template<typename ...> class A>
+class basic_value;
+
 namespace detail
 {
-
-template<typename T>
-using unwrap_t = typename std::decay<T>::type;
+// ---------------------------------------------------------------------------
+// check whether type T is a kind of container/map class
 
 struct has_iterator_impl
 {
@@ -35,12 +50,60 @@ struct has_mapped_type_impl
     template<typename T> static std::true_type  check(typename T::mapped_type*);
     template<typename T> static std::false_type check(...);
 };
-struct has_resize_method_impl
+struct has_reserve_method_impl
 {
-    constexpr static std::size_t dummy=0;
-    template<typename T> static std::true_type  check(decltype(std::declval<T>().resize(dummy))*);
     template<typename T> static std::false_type check(...);
+    template<typename T> static std::true_type  check(
+        decltype(std::declval<T>().reserve(std::declval<std::size_t>()))*);
 };
+struct has_push_back_method_impl
+{
+    template<typename T> static std::false_type check(...);
+    template<typename T> static std::true_type  check(
+        decltype(std::declval<T>().push_back(std::declval<typename T::value_type>()))*);
+};
+struct is_comparable_impl
+{
+    template<typename T> static std::false_type check(...);
+    template<typename T> static std::true_type  check(
+        decltype(std::declval<T>() < std::declval<T>())*);
+};
+
+struct has_from_toml_method_impl
+{
+    template<typename T, typename C,
+             template<typename ...> class Tb, template<typename ...> class A>
+    static std::true_type  check(
+        decltype(std::declval<T>().from_toml(
+                std::declval<::toml::basic_value<C, Tb, A>>()))*);
+
+    template<typename T, typename C,
+             template<typename ...> class Tb, template<typename ...> class A>
+    static std::false_type check(...);
+};
+struct has_into_toml_method_impl
+{
+    template<typename T>
+    static std::true_type  check(decltype(std::declval<T>().into_toml())*);
+    template<typename T>
+    static std::false_type check(...);
+};
+
+struct has_specialized_from_impl
+{
+    template<typename T>
+    static std::false_type check(...);
+    template<typename T, std::size_t S = sizeof(::toml::from<T>)>
+    static std::true_type check(::toml::from<T>*);
+};
+struct has_specialized_into_impl
+{
+    template<typename T>
+    static std::false_type check(...);
+    template<typename T, std::size_t S = sizeof(::toml::into<T>)>
+    static std::true_type check(::toml::from<T>*);
+};
+
 
 /// Intel C++ compiler can not use decltype in parent class declaration, here
 /// is a hack to work around it. https://stackoverflow.com/a/23953090/4692076
@@ -57,12 +120,41 @@ struct has_key_type    : decltype(has_key_type_impl::check<T>(nullptr)){};
 template<typename T>
 struct has_mapped_type : decltype(has_mapped_type_impl::check<T>(nullptr)){};
 template<typename T>
-struct has_resize_method : decltype(has_resize_method_impl::check<T>(nullptr)){};
+struct has_reserve_method : decltype(has_reserve_method_impl::check<T>(nullptr)){};
+template<typename T>
+struct has_push_back_method : decltype(has_push_back_method_impl::check<T>(nullptr)){};
+template<typename T>
+struct is_comparable : decltype(is_comparable_impl::check<T>(nullptr)){};
+
+template<typename T, typename C,
+         template<typename ...> class Tb, template<typename ...> class A>
+struct has_from_toml_method
+: decltype(has_from_toml_method_impl::check<T, C, Tb, A>(nullptr)){};
+
+template<typename T>
+struct has_into_toml_method
+: decltype(has_into_toml_method_impl::check<T>(nullptr)){};
+
+template<typename T>
+struct has_specialized_from : decltype(has_specialized_from_impl::check<T>(nullptr)){};
+template<typename T>
+struct has_specialized_into : decltype(has_specialized_into_impl::check<T>(nullptr)){};
 
 #ifdef __INTEL_COMPILER
-#undef decltype(...)
+#undef decltype
 #endif
 
+// ---------------------------------------------------------------------------
+// C++17 and/or/not
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+
+using std::conjunction;
+using std::disjunction;
+using std::negation;
+
+#else
+
 template<typename ...> struct conjunction : std::true_type{};
 template<typename T>   struct conjunction<T> : T{};
 template<typename T, typename ... Ts>
@@ -80,6 +172,11 @@ struct disjunction<T, Ts...> :
 template<typename T>
 struct negation : std::integral_constant<bool, !static_cast<bool>(T::value)>{};
 
+#endif
+
+// ---------------------------------------------------------------------------
+// type checkers
+
 template<typename T> struct is_std_pair : std::false_type{};
 template<typename T1, typename T2>
 struct is_std_pair<std::pair<T1, T2>> : std::true_type{};
@@ -88,11 +185,62 @@ template<typename T> struct is_std_tuple : std::false_type{};
 template<typename ... Ts>
 struct is_std_tuple<std::tuple<Ts...>> : std::true_type{};
 
+template<typename T> struct is_std_forward_list : std::false_type{};
+template<typename T>
+struct is_std_forward_list<std::forward_list<T>> : std::true_type{};
+
 template<typename T> struct is_chrono_duration: std::false_type{};
 template<typename Rep, typename Period>
 struct is_chrono_duration<std::chrono::duration<Rep, Period>>: std::true_type{};
 
-// to use toml::get<std::tuple<T1, T2, ...>> in C++11
+template<typename T>
+struct is_map : conjunction< // map satisfies all the following conditions
+    has_iterator<T>,         // has T::iterator
+    has_value_type<T>,       // has T::value_type
+    has_key_type<T>,         // has T::key_type
+    has_mapped_type<T>       // has T::mapped_type
+    >{};
+template<typename T> struct is_map<T&>                : is_map<T>{};
+template<typename T> struct is_map<T const&>          : is_map<T>{};
+template<typename T> struct is_map<T volatile&>       : is_map<T>{};
+template<typename T> struct is_map<T const volatile&> : is_map<T>{};
+
+template<typename T>
+struct is_container : conjunction<
+    negation<is_map<T>>,                         // not a map
+    negation<std::is_same<T, std::string>>,      // not a std::string
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L
+#if __has_include(<string_view>)
+    negation<std::is_same<T, std::string_view>>, // not a std::string_view
+#endif // has_include(<string_view>)
+#endif
+    has_iterator<T>,                             // has T::iterator
+    has_value_type<T>                            // has T::value_type
+    >{};
+template<typename T> struct is_container<T&>                : is_container<T>{};
+template<typename T> struct is_container<T const&>          : is_container<T>{};
+template<typename T> struct is_container<T volatile&>       : is_container<T>{};
+template<typename T> struct is_container<T const volatile&> : is_container<T>{};
+
+template<typename T>
+struct is_basic_value: std::false_type{};
+template<typename T> struct is_basic_value<T&>                : is_basic_value<T>{};
+template<typename T> struct is_basic_value<T const&>          : is_basic_value<T>{};
+template<typename T> struct is_basic_value<T volatile&>       : is_basic_value<T>{};
+template<typename T> struct is_basic_value<T const volatile&> : is_basic_value<T>{};
+template<typename C, template<typename ...> class M, template<typename ...> class V>
+struct is_basic_value<::toml::basic_value<C, M, V>>: std::true_type{};
+
+// ---------------------------------------------------------------------------
+// C++14 index_sequence
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201402L
+
+using std::index_sequence;
+using std::make_index_sequence;
+
+#else
+
 template<std::size_t ... Ns> struct index_sequence{};
 
 template<typename IS, std::size_t N> struct push_back_index_sequence{};
@@ -116,6 +264,65 @@ struct index_sequence_maker<0>
 template<std::size_t N>
 using make_index_sequence = typename index_sequence_maker<N-1>::type;
 
+#endif // cplusplus >= 2014
+
+// ---------------------------------------------------------------------------
+// C++14 enable_if_t
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201402L
+
+using std::enable_if_t;
+
+#else
+
+template<bool B, typename T>
+using enable_if_t = typename std::enable_if<B, T>::type;
+
+#endif // cplusplus >= 2014
+
+// ---------------------------------------------------------------------------
+// return_type_of_t
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201703L && defined(__cpp_lib_is_invocable) && __cpp_lib_is_invocable>=201703
+
+template<typename F, typename ... Args>
+using return_type_of_t = std::invoke_result_t<F, Args...>;
+
+#else
+// result_of is deprecated after C++17
+template<typename F, typename ... Args>
+using return_type_of_t = typename std::result_of<F(Args...)>::type;
+
+#endif
+
+// ---------------------------------------------------------------------------
+// is_string_literal
+//
+// to use this, pass `typename remove_reference<T>::type` to T.
+
+template<typename T>
+struct is_string_literal:
+disjunction<
+    std::is_same<const char*, T>,
+    conjunction<
+        std::is_array<T>,
+        std::is_same<const char, typename std::remove_extent<T>::type>
+        >
+    >{};
+
+// ---------------------------------------------------------------------------
+// C++20 remove_cvref_t
+
+template<typename T>
+struct remove_cvref
+{
+    using type = typename std::remove_cv<
+        typename std::remove_reference<T>::type>::type;
+};
+
+template<typename T>
+using remove_cvref_t = typename remove_cvref<T>::type;
+
 }// detail
 }//toml
 #endif // TOML_TRAITS

toml/types.hpp

@@ -1,55 +1,79 @@
 //     Copyright Toru Niina 2017.
 // Distributed under the MIT License.
-#ifndef TOML11_TYPES_H
-#define TOML11_TYPES_H
+#ifndef TOML11_TYPES_HPP
+#define TOML11_TYPES_HPP
+#include <unordered_map>
+#include <vector>
+
+#include "comments.hpp"
 #include "datetime.hpp"
 #include "string.hpp"
 #include "traits.hpp"
-#include <vector>
-#include <unordered_map>
 
 namespace toml
 {
 
-using character = char;
+template<typename Comment, // discard/preserve_comment
+         template<typename ...> class Table, // map-like class
+         template<typename ...> class Array> // vector-like class
+class basic_value;
 
-class value;
+using character = char;
 using key = std::string;
 
-using Boolean        = bool;
-using Integer        = std::int64_t;
-using Float          = double;
-using String         = ::toml::string;
-using Datetime       = offset_datetime;
-using OffsetDatetime = offset_datetime;
-using LocalDatetime  = local_datetime;
-using LocalDate      = local_date;
-using LocalTime      = local_time;
-using Array          = std::vector<value>;
-using Table          = std::unordered_map<key, value>;
+#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ <= 4
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wshadow"
+#endif
 
-// alias for snake_case, consistency with STL/Boost, toml::key, toml::value
-using boolean  = Boolean;
-using integer  = Integer;
-using floating = Float;   // XXX `float` is keyword. we can't use it here
-using array    = Array;
-using table    = Table;
+using boolean        = bool;
+using integer        = std::int64_t;
+using floating       = double; // "float" is a keyword, cannot use it here.
+// the following stuffs are structs defined here, so aliases are not needed.
+// - string
+// - offset_datetime
+// - offset_datetime
+// - local_datetime
+// - local_date
+// - local_time
 
+#if defined(__GNUC__) && !defined(__clang__)
+#  pragma GCC diagnostic pop
+#endif
+
+// default toml::value and default array/table. these are defined after defining
+// basic_value itself.
+// using value = basic_value<discard_comments, std::unordered_map, std::vector>;
+// using array = typename value::array_type;
+// using table = typename value::table_type;
+
+// to avoid warnings about `value_t::integer` is "shadowing" toml::integer in
+// GCC -Wshadow=global.
+#if defined(__GNUC__) && !defined(__clang__)
+#  pragma GCC diagnostic push
+#  if 7 <= __GNUC__
+#    pragma GCC diagnostic ignored "-Wshadow=global"
+#  else // gcc-6 or older
+#    pragma GCC diagnostic ignored "-Wshadow"
+#  endif
+#endif
 enum class value_t : std::uint8_t
 {
-    Empty          = 0,
-    Boolean        = 1,
-    Integer        = 2,
-    Float          = 3,
-    String         = 4,
-    OffsetDatetime = 5,
-    LocalDatetime  = 6,
-    LocalDate      = 7,
-    LocalTime      = 8,
-    Array          = 9,
-    Table          = 10,
-    Unknown        = 255,
+    empty           =  0,
+    boolean         =  1,
+    integer         =  2,
+    floating        =  3,
+    string          =  4,
+    offset_datetime =  5,
+    local_datetime  =  6,
+    local_date      =  7,
+    local_time      =  8,
+    array           =  9,
+    table           = 10,
 };
+#if defined(__GNUC__) && !defined(__clang__)
+#  pragma GCC diagnostic pop
+#endif
 
 template<typename charT, typename traits>
 inline std::basic_ostream<charT, traits>&
@@ -57,27 +81,27 @@ operator<<(std::basic_ostream<charT, traits>& os, value_t t)
 {
     switch(t)
     {
-        case toml::value_t::Boolean       : os << "boolean";         return os;
-        case toml::value_t::Integer       : os << "integer";         return os;
-        case toml::value_t::Float         : os << "float";           return os;
-        case toml::value_t::String        : os << "string";          return os;
-        case toml::value_t::OffsetDatetime: os << "offset_datetime"; return os;
-        case toml::value_t::LocalDatetime : os << "local_datetime";  return os;
-        case toml::value_t::LocalDate     : os << "local_date";      return os;
-        case toml::value_t::LocalTime     : os << "local_time";      return os;
-        case toml::value_t::Array         : os << "array";           return os;
-        case toml::value_t::Table         : os << "table";           return os;
-        case toml::value_t::Empty         : os << "empty";           return os;
-        case toml::value_t::Unknown       : os << "unknown";         return os;
-        default                           : os << "nothing";         return os;
+        case value_t::boolean         : os << "boolean";         return os;
+        case value_t::integer         : os << "integer";         return os;
+        case value_t::floating        : os << "floating";        return os;
+        case value_t::string          : os << "string";          return os;
+        case value_t::offset_datetime : os << "offset_datetime"; return os;
+        case value_t::local_datetime  : os << "local_datetime";  return os;
+        case value_t::local_date      : os << "local_date";      return os;
+        case value_t::local_time      : os << "local_time";      return os;
+        case value_t::array           : os << "array";           return os;
+        case value_t::table           : os << "table";           return os;
+        case value_t::empty           : os << "empty";           return os;
+        default                       : os << "unknown";         return os;
     }
 }
 
-template<typename charT = character, typename traits = std::char_traits<charT>,
+template<typename charT = char,
+         typename traits = std::char_traits<charT>,
          typename alloc = std::allocator<charT>>
 inline std::basic_string<charT, traits, alloc> stringize(value_t t)
 {
-    std::ostringstream oss;
+    std::basic_ostringstream<charT, traits, alloc> oss;
     oss << t;
     return oss.str();
 }
@@ -85,113 +109,65 @@ inline std::basic_string<charT, traits, alloc> stringize(value_t t)
 namespace detail
 {
 
-template<typename T>
-constexpr inline value_t check_type()
-{
-    using type = typename std::remove_cv<
-                 typename std::remove_reference<T>::type
-                 >::type;
-    return std::is_same<type, toml::boolean>::value                         ? value_t::Boolean        :
-           std::is_integral<type>::value                                    ? value_t::Integer        :
-           std::is_floating_point<type>::value                              ? value_t::Float          :
-           std::is_same<type, std::string>::value                           ? value_t::String         :
-           std::is_same<type, toml::string>::value                          ? value_t::String         :
-           std::is_same<type, toml::local_date>::value                      ? value_t::LocalDate      :
-           std::is_same<type, toml::local_time>::value                      ? value_t::LocalTime      :
-           is_chrono_duration<type>::value                                  ? value_t::LocalTime      :
-           std::is_same<type, toml::local_datetime>::value                  ? value_t::LocalDatetime  :
-           std::is_same<type, toml::offset_datetime>::value                 ? value_t::OffsetDatetime :
-           std::is_same<type, std::chrono::system_clock::time_point>::value ? value_t::OffsetDatetime :
-           std::is_convertible<type, toml::array>::value                    ? value_t::Array          :
-           std::is_convertible<type, toml::table>::value                    ? value_t::Table          :
-           value_t::Unknown;
-}
+// helper to define a type that represents a value_t value.
+template<value_t V>
+using value_t_constant = std::integral_constant<value_t, V>;
 
-constexpr inline bool is_valid(value_t vt)
-{
-    return vt != value_t::Unknown;
-}
+// meta-function that convertes from value_t to the exact toml type that corresponds to.
+// It takes toml::basic_value type because array and table types depend on it.
+template<value_t t, typename Value> struct enum_to_type                      {using type = void                      ;};
+template<typename Value> struct enum_to_type<value_t::empty          , Value>{using type = void                      ;};
+template<typename Value> struct enum_to_type<value_t::boolean        , Value>{using type = boolean                   ;};
+template<typename Value> struct enum_to_type<value_t::integer        , Value>{using type = integer                   ;};
+template<typename Value> struct enum_to_type<value_t::floating       , Value>{using type = floating                  ;};
+template<typename Value> struct enum_to_type<value_t::string         , Value>{using type = string                    ;};
+template<typename Value> struct enum_to_type<value_t::offset_datetime, Value>{using type = offset_datetime           ;};
+template<typename Value> struct enum_to_type<value_t::local_datetime , Value>{using type = local_datetime            ;};
+template<typename Value> struct enum_to_type<value_t::local_date     , Value>{using type = local_date                ;};
+template<typename Value> struct enum_to_type<value_t::local_time     , Value>{using type = local_time                ;};
+template<typename Value> struct enum_to_type<value_t::array          , Value>{using type = typename Value::array_type;};
+template<typename Value> struct enum_to_type<value_t::table          , Value>{using type = typename Value::table_type;};
 
-template<value_t t> struct toml_default_type;
-template<> struct toml_default_type<value_t::Boolean >      {typedef boolean         type;};
-template<> struct toml_default_type<value_t::Integer >      {typedef integer         type;};
-template<> struct toml_default_type<value_t::Float   >      {typedef floating        type;};
-template<> struct toml_default_type<value_t::String  >      {typedef string          type;};
-template<> struct toml_default_type<value_t::OffsetDatetime>{typedef offset_datetime type;};
-template<> struct toml_default_type<value_t::LocalDatetime> {typedef local_datetime  type;};
-template<> struct toml_default_type<value_t::LocalDate>     {typedef local_date      type;};
-template<> struct toml_default_type<value_t::LocalTime>     {typedef local_time      type;};
-template<> struct toml_default_type<value_t::Array   >      {typedef array           type;};
-template<> struct toml_default_type<value_t::Table   >      {typedef table           type;};
-template<> struct toml_default_type<value_t::Empty   >      {typedef void            type;};
-template<> struct toml_default_type<value_t::Unknown >      {typedef void            type;};
+// meta-function that converts from an exact toml type to the enum that corresponds to.
+template<typename T, typename Value>
+struct type_to_enum : std::conditional<
+    std::is_same<T, typename Value::array_type>::value, // if T == array_type,
+    value_t_constant<value_t::array>,                   // then value_t::array
+    typename std::conditional<                          // else...
+        std::is_same<T, typename Value::table_type>::value, // if T == table_type
+        value_t_constant<value_t::table>,               // then value_t::table
+        value_t_constant<value_t::empty>                // else value_t::empty
+        >::type
+    >::type {};
+template<typename Value> struct type_to_enum<boolean        , Value>: value_t_constant<value_t::boolean        > {};
+template<typename Value> struct type_to_enum<integer        , Value>: value_t_constant<value_t::integer        > {};
+template<typename Value> struct type_to_enum<floating       , Value>: value_t_constant<value_t::floating       > {};
+template<typename Value> struct type_to_enum<string         , Value>: value_t_constant<value_t::string         > {};
+template<typename Value> struct type_to_enum<offset_datetime, Value>: value_t_constant<value_t::offset_datetime> {};
+template<typename Value> struct type_to_enum<local_datetime , Value>: value_t_constant<value_t::local_datetime > {};
+template<typename Value> struct type_to_enum<local_date     , Value>: value_t_constant<value_t::local_date     > {};
+template<typename Value> struct type_to_enum<local_time     , Value>: value_t_constant<value_t::local_time     > {};
 
-template<typename T> struct toml_value_t      {static constexpr value_t value = value_t::Unknown       ;};
-template<> struct toml_value_t<Boolean       >{static constexpr value_t value = value_t::Boolean       ;};
-template<> struct toml_value_t<Integer       >{static constexpr value_t value = value_t::Integer       ;};
-template<> struct toml_value_t<Float         >{static constexpr value_t value = value_t::Float         ;};
-template<> struct toml_value_t<String        >{static constexpr value_t value = value_t::String        ;};
-template<> struct toml_value_t<OffsetDatetime>{static constexpr value_t value = value_t::OffsetDatetime;};
-template<> struct toml_value_t<LocalDatetime >{static constexpr value_t value = value_t::LocalDatetime ;};
-template<> struct toml_value_t<LocalDate     >{static constexpr value_t value = value_t::LocalDate     ;};
-template<> struct toml_value_t<LocalTime     >{static constexpr value_t value = value_t::LocalTime     ;};
-template<> struct toml_value_t<Array         >{static constexpr value_t value = value_t::Array         ;};
-template<> struct toml_value_t<Table         >{static constexpr value_t value = value_t::Table         ;};
-template<typename T> constexpr value_t toml_value_t<T>::value;
-constexpr value_t toml_value_t<Boolean       >::value;
-constexpr value_t toml_value_t<Integer       >::value;
-constexpr value_t toml_value_t<Float         >::value;
-constexpr value_t toml_value_t<String        >::value;
-constexpr value_t toml_value_t<OffsetDatetime>::value;
-constexpr value_t toml_value_t<LocalDatetime >::value;
-constexpr value_t toml_value_t<LocalDate     >::value;
-constexpr value_t toml_value_t<LocalTime     >::value;
-constexpr value_t toml_value_t<Array         >::value;
-constexpr value_t toml_value_t<Table         >::value;
-
-template<typename T>
+// meta-function that checks the type T is the same as one of the toml::* types.
+template<typename T, typename Value>
 struct is_exact_toml_type : disjunction<
-    std::is_same<T, Boolean >,
-    std::is_same<T, Integer >,
-    std::is_same<T, Float   >,
-    std::is_same<T, String  >,
+    std::is_same<T, boolean        >,
+    std::is_same<T, integer        >,
+    std::is_same<T, floating       >,
+    std::is_same<T, string         >,
     std::is_same<T, offset_datetime>,
-    std::is_same<T, local_datetime>,
-    std::is_same<T, local_date>,
-    std::is_same<T, local_time>,
-    std::is_same<T, Array   >,
-    std::is_same<T, Table   >
+    std::is_same<T, local_datetime >,
+    std::is_same<T, local_date     >,
+    std::is_same<T, local_time     >,
+    std::is_same<T, typename Value::array_type>,
+    std::is_same<T, typename Value::table_type>
     >{};
-template<typename T> struct is_exact_toml_type<T&>               : is_exact_toml_type<T>{};
-template<typename T> struct is_exact_toml_type<T const&>         : is_exact_toml_type<T>{};
-template<typename T> struct is_exact_toml_type<T volatile&>      : is_exact_toml_type<T>{};
-template<typename T> struct is_exact_toml_type<T const volatile&>: is_exact_toml_type<T>{};
-
-template<typename T>
-struct is_map : conjunction<
-    has_iterator<T>,
-    has_value_type<T>,
-    has_key_type<T>,
-    has_mapped_type<T>
-    >{};
-template<typename T> struct is_map<T&>                : is_map<T>{};
-template<typename T> struct is_map<T const&>          : is_map<T>{};
-template<typename T> struct is_map<T volatile&>       : is_map<T>{};
-template<typename T> struct is_map<T const volatile&> : is_map<T>{};
-
-template<typename T>
-struct is_container : conjunction<
-    negation<is_map<T>>,
-    negation<std::is_same<T, std::string>>,
-    has_iterator<T>,
-    has_value_type<T>
-    >{};
-template<typename T> struct is_container<T&>                : is_container<T>{};
-template<typename T> struct is_container<T const&>          : is_container<T>{};
-template<typename T> struct is_container<T volatile&>       : is_container<T>{};
-template<typename T> struct is_container<T const volatile&> : is_container<T>{};
-
+template<typename T, typename V> struct is_exact_toml_type<T&, V>               : is_exact_toml_type<T, V>{};
+template<typename T, typename V> struct is_exact_toml_type<T const&, V>         : is_exact_toml_type<T, V>{};
+template<typename T, typename V> struct is_exact_toml_type<T volatile&, V>      : is_exact_toml_type<T, V>{};
+template<typename T, typename V> struct is_exact_toml_type<T const volatile&, V>: is_exact_toml_type<T, V>{};
 
 } // detail
 } // toml
+
 #endif// TOML11_TYPES_H

toml/utility.hpp

@@ -1,45 +1,62 @@
 //     Copyright Toru Niina 2017.
 // Distributed under the MIT License.
-#ifndef TOML11_UTILITY
-#define TOML11_UTILITY
-#include "traits.hpp"
-#include <utility>
+#ifndef TOML11_UTILITY_HPP
+#define TOML11_UTILITY_HPP
 #include <memory>
 #include <sstream>
+#include <utility>
+
+#include "traits.hpp"
+#include "version.hpp"
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201402L
+#  define TOML11_MARK_AS_DEPRECATED(msg) [[deprecated(msg)]]
+#elif defined(__GNUC__)
+#  define TOML11_MARK_AS_DEPRECATED(msg) __attribute__((deprecated(msg)))
+#elif defined(_MSC_VER)
+#  define TOML11_MARK_AS_DEPRECATED(msg) __declspec(deprecated(msg))
+#else
+#  define TOML11_MARK_AS_DEPRECATED
+#endif
 
 namespace toml
 {
 
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201402L
+
+using std::make_unique;
+
+#else
+
 template<typename T, typename ... Ts>
 inline std::unique_ptr<T> make_unique(Ts&& ... args)
 {
     return std::unique_ptr<T>(new T(std::forward<Ts>(args)...));
 }
 
+#endif // TOML11_CPLUSPLUS_STANDARD_VERSION >= 2014
+
 namespace detail
 {
-
-template<typename T>
-inline void resize_impl(T& container, std::size_t N, std::true_type)
+template<typename Container>
+void try_reserve_impl(Container& container, std::size_t N, std::true_type)
 {
-    container.resize(N);
-    return ;
+    container.reserve(N);
+    return;
 }
-
-template<typename T>
-inline void resize_impl(T& container, std::size_t N, std::false_type)
+template<typename Container>
+void try_reserve_impl(Container&, std::size_t, std::false_type) noexcept
 {
-    if(container.size() >= N) return;
-    else throw std::invalid_argument("not resizable type");
+    return;
 }
-
 } // detail
 
-template<typename T>
-inline void resize(T& container, std::size_t N)
+template<typename Container>
+void try_reserve(Container& container, std::size_t N)
 {
-    if(container.size() == N) return;
-    else return detail::resize_impl(container, N, detail::has_resize_method<T>());
+    if(N <= container.size()) {return;}
+    detail::try_reserve_impl(container, N, detail::has_reserve_method<Container>{});
+    return;
 }
 
 namespace detail
@@ -64,16 +81,70 @@ std::string concat_to_string(Ts&& ... args)
     return detail::concat_to_string_impl(oss, std::forward<Ts>(args) ...);
 }
 
-template<typename T, typename U>
-T from_string(const std::string& str, U&& opt)
+template<typename T>
+T from_string(const std::string& str, T opt)
 {
-    T v(std::forward<U>(opt));
+    T v(opt);
     std::istringstream iss(str);
     iss >> v;
     return v;
 }
 
+namespace detail
+{
+#if TOML11_CPLUSPLUS_STANDARD_VERSION >= 201402L
+template<typename T>
+decltype(auto) last_one(T&& tail) noexcept
+{
+    return std::forward<T>(tail);
+}
 
+template<typename T, typename ... Ts>
+decltype(auto) last_one(T&& /*head*/, Ts&& ... tail) noexcept
+{
+    return last_one(std::forward<Ts>(tail)...);
+}
+#else // C++11
+// The following code
+// ```cpp
+//  1 | template<typename T, typename ... Ts>
+//  2 | auto last_one(T&& /*head*/, Ts&& ... tail)
+//  3 |  -> decltype(last_one(std::forward<Ts>(tail)...))
+//  4 | {
+//  5 |     return last_one(std::forward<Ts>(tail)...);
+//  6 | }
+// ```
+// does not work because the function `last_one(...)` is not yet defined at
+// line #3, so `decltype()` cannot deduce the type returned from `last_one`.
+// So we need to determine return type in a different way, like a meta func.
+
+template<typename T, typename ... Ts>
+struct last_one_in_pack
+{
+    using type = typename last_one_in_pack<Ts...>::type;
+};
+template<typename T>
+struct last_one_in_pack<T>
+{
+    using type = T;
+};
+template<typename ... Ts>
+using last_one_in_pack_t = typename last_one_in_pack<Ts...>::type;
+
+template<typename T>
+T&& last_one(T&& tail) noexcept
+{
+    return std::forward<T>(tail);
+}
+template<typename T, typename ... Ts>
+enable_if_t<(sizeof...(Ts) > 0), last_one_in_pack_t<Ts&& ...>>
+last_one(T&& /*head*/, Ts&& ... tail)
+{
+    return last_one(std::forward<Ts>(tail)...);
+}
+
+#endif
+} // detail
 
 }// toml
 #endif // TOML11_UTILITY

toml/version.hpp

@@ -0,0 +1,42 @@
+#ifndef TOML11_VERSION_HPP
+#define TOML11_VERSION_HPP
+
+// This file checks C++ version.
+
+#ifndef __cplusplus
+#    error "__cplusplus is not defined"
+#endif
+
+// Since MSVC does not define `__cplusplus` correctly unless you pass
+// `/Zc:__cplusplus` when compiling, the workaround macros are added.
+// Those enables you to define version manually or to use MSVC specific
+// version macro automatically.
+//
+// The value of `__cplusplus` macro is defined in the C++ standard spec, but
+// MSVC ignores the value, maybe because of backward compatibility. Instead,
+// MSVC defines _MSVC_LANG that has the same value as __cplusplus defined in
+// the C++ standard. First we check the manual version definition, and then
+// we check if _MSVC_LANG is defined. If neither, use normal `__cplusplus`.
+//
+// FYI: https://docs.microsoft.com/en-us/cpp/build/reference/zc-cplusplus?view=msvc-170
+//      https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros?view=msvc-170
+//
+#if   defined(TOML11_ENFORCE_CXX11)
+#  define TOML11_CPLUSPLUS_STANDARD_VERSION 201103L
+#elif defined(TOML11_ENFORCE_CXX14)
+#  define TOML11_CPLUSPLUS_STANDARD_VERSION 201402L
+#elif defined(TOML11_ENFORCE_CXX17)
+#  define TOML11_CPLUSPLUS_STANDARD_VERSION 201703L
+#elif defined(TOML11_ENFORCE_CXX20)
+#  define TOML11_CPLUSPLUS_STANDARD_VERSION 202002L
+#elif defined(_MSVC_LANG) && defined(_MSC_VER) && 1910 <= _MSC_VER
+#  define TOML11_CPLUSPLUS_STANDARD_VERSION _MSVC_LANG
+#else
+#  define TOML11_CPLUSPLUS_STANDARD_VERSION __cplusplus
+#endif
+
+#if TOML11_CPLUSPLUS_STANDARD_VERSION < 201103L && _MSC_VER < 1900
+#    error "toml11 requires C++11 or later."
+#endif
+
+#endif// TOML11_VERSION_HPP