doc: update README

When non-table value is passed to the `operator<<`, it assumes that the
original C++ code looks like the following.

```cpp
std::cout << "key = " << v << std::endl;
```

In this case, the comment associated to `v` should be put just after
`v`, not before.
```toml
key = # comment <= bad
"value"

key = "value" # comment <= good
```

So, if `v` is not a table it would put comments just after the value.

.circleci/config.yml

@@ -15,6 +15,29 @@ jobs:
               g++ -std=c++11 -O2 -Wall -Wextra -Werror -I../ check_toml_test.cpp -o check_toml_test
               go get github.com/BurntSushi/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
@@ -24,7 +47,7 @@ jobs:
           command: |
               g++ --version
               cd tests/
-              g++ -std=c++11 -O2 -Wall -Wextra -Werror -I../ check.cpp -o check
+              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
@@ -56,4 +79,5 @@ workflows:
   test:
     jobs:
       - test_suite
+      - test_serialization
       - output_result

.travis.yml

@@ -5,127 +5,180 @@ matrix:
   - os: linux
     language: cpp
     compiler: gcc
-    env: COMPILER="g++-5"
+    env: COMPILER="g++-5" CXX_STANDARD=11
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:mhier/libboost-latest'
         packages:
         - g++-5
-        - libboost-all-dev
+        - boost1.70
   - os: linux
     language: cpp
     compiler: gcc
-    env: COMPILER="g++-6"
+    env: COMPILER="g++-6" CXX_STANDARD=11
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:mhier/libboost-latest'
         packages:
         - g++-6
-        - libboost-all-dev
+        - boost1.70
   - os: linux
     language: cpp
     compiler: gcc
-    env: COMPILER="g++-7"
+    env: COMPILER="g++-7" CXX_STANDARD=11
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:mhier/libboost-latest'
         packages:
         - g++-7
-        - libboost-all-dev
+        - boost1.70
   - os: linux
     language: cpp
     compiler: gcc
-    env: COMPILER="g++-8"
+    env: COMPILER="g++-8" CXX_STANDARD=11
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:mhier/libboost-latest'
         packages:
         - g++-8
-        - libboost-all-dev
+        - boost1.70
+  - os: linux
+    language: cpp
+    compiler: gcc
+    env: COMPILER="g++-8" CXX_STANDARD=17
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:mhier/libboost-latest'
+        packages:
+        - g++-8
+        - boost1.70
   - os: linux
     language: cpp
     compiler: clang
-    env: COMPILER="clang++-3.7"
+    env: COMPILER="clang++-3.7" CXX_STANDARD=11
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
         - llvm-toolchain-precise-3.7
+        - sourceline: 'ppa:mhier/libboost-latest'
         packages:
+        - g++-8
         - clang-3.7
-        - libboost-all-dev
+        - boost1.70
   - os: linux
     language: cpp
     compiler: clang
-    env: COMPILER="clang++-4.0"
+    env: COMPILER="clang++-4.0" CXX_STANDARD=11
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
         - llvm-toolchain-trusty-4.0
+        - sourceline: 'ppa:mhier/libboost-latest'
         packages:
+        - g++-8
         - clang-4.0
-        - libboost-all-dev
+        - boost1.70
   - os: linux
     language: cpp
     compiler: clang
-    env: COMPILER="clang++-5.0"
+    env: COMPILER="clang++-5.0" CXX_STANDARD=11
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
         - llvm-toolchain-trusty-5.0
+        - sourceline: 'ppa:mhier/libboost-latest'
         packages:
+        - g++-8
         - clang-5.0
-        - libboost-all-dev
+        - boost1.70
   - os: linux
     language: cpp
     compiler: clang
-    env: COMPILER="clang++-6.0"
+    env: COMPILER="clang++-6.0" CXX_STANDARD=11
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
         - llvm-toolchain-trusty-6.0
+        - sourceline: 'ppa:mhier/libboost-latest'
         packages:
+        - g++-8
         - clang-6.0
-        - libboost-all-dev
+        - boost1.70
   - os: linux
     language: cpp
     compiler: clang
-    env: COMPILER="clang++-7"
+    env: COMPILER="clang++-7" CXX_STANDARD=11
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
         - llvm-toolchain-trusty-7
+        - sourceline: 'ppa:mhier/libboost-latest'
         packages:
+        - g++-8
         - clang-7
-        - libboost-all-dev
+        - boost1.70
   - os: linux
     language: cpp
     compiler: clang
-    env: COMPILER="clang++-8"
+    env: COMPILER="clang++-8" CXX_STANDARD=11
     addons:
       apt:
         sources:
         - ubuntu-toolchain-r-test
         - llvm-toolchain-trusty-8
+        - sourceline: 'ppa:mhier/libboost-latest'
+        packages:
+        - g++-8
+        - clang-8
+        - boost1.70
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-8" CXX_STANDARD=17
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        - llvm-toolchain-trusty-8
+        - sourceline: 'ppa:mhier/libboost-latest'
         packages:
         - clang-8
-        - libboost-all-dev
+        - g++-8
+        - boost1.70
   - os: osx
     language: cpp
     compiler: clang
+    env: CXX_STANDARD=11
 
 script:
+- |
+  if [[ "${TRAVIS_OS_NAME}" == "linux" ]]; then
+    mkdir -p cmake
+    travis_retry wget "https://github.com/Kitware/CMake/releases/download/v3.14.5/cmake-3.14.5-Linux-x86_64.tar.gz"
+    tar xf cmake-3.14.5-Linux-x86_64.tar.gz -C cmake --strip-components=1
+    export PATH=${TRAVIS_BUILD_DIR}/cmake/bin:${PATH}
+  else
+    brew upgrade cmake boost
+  fi
+- cmake --version
 - mkdir build
 - cd build
 - git clone https://github.com/toml-lang/toml.git
-- cmake -DCMAKE_CXX_COMPILER=$COMPILER ..
+- cmake -DCMAKE_CXX_COMPILER=$COMPILER -DCMAKE_CXX_STANDARD=$CXX_STANDARD ..
 - make
 - ctest --output-on-failure

CMakeLists.txt

@@ -1,10 +1,23 @@
 cmake_minimum_required(VERSION 2.8)
 enable_testing()
+
 project(toml11)
 
+set(toml11_VERSION_MAYOR  3)
+set(toml11_VERSION_MINOR  0)
+set(toml11_VERSION_PATCH  0)
+set(toml11_VERSION
+  "${toml11_VERSION_MAYOR}.${toml11_VERSION_MINOR}.${toml11_VERSION_PATCH}-beta"
+)
+
+option(toml11_BUILD_TEST "Build toml tests" ON)
+
 include(CheckCXXCompilerFlag)
 if("${CMAKE_VERSION}" VERSION_GREATER 3.1)
-    set(CMAKE_CXX_STANDARD 11)
+    set(CMAKE_CXX_EXTENSIONS OFF)
+    if(NOT DEFINED CMAKE_CXX_STANDARD)
+        set(CMAKE_CXX_STANDARD 11)
+    endif()
     set(CXX_STANDARD_REQUIRED ON)
 else()
     # Manually check for C++11 compiler flag.
@@ -31,5 +44,62 @@ else()
     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
+)
+
+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::
+)
+
+if (toml11_BUILD_TEST)
+    add_subdirectory(tests)
+endif ()

appveyor.yml

@@ -19,7 +19,7 @@ build_script:
   - 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%" -DBOOST_ROOT=C:/Libraries/boost_1_69_0 ..
   - cmake --build . --config "%configuration%"
 
 test_script:

cmake/toml11Config.cmake.in

@@ -0,0 +1,2 @@
+@PACKAGE_INIT@
+include("@PACKAGE_toml11_install_cmake_dir@/toml11Targets.cmake")

tests/CMakeLists.txt

@@ -1,5 +1,6 @@
 set(TEST_NAMES
     test_datetime
+    test_string
     test_utility
     test_result
     test_traits
@@ -21,9 +22,12 @@ set(TEST_NAMES
     test_parse_key
     test_parse_table_key
     test_literals
+    test_comments
     test_get
-    test_get_related_func
-    test_from_toml
+    test_get_or
+    test_find
+    test_find_or
+    test_expect
     test_parse_file
     test_serialize_file
     test_parse_unicode
@@ -32,13 +36,16 @@ set(TEST_NAMES
     test_extended_conversions
 )
 
-CHECK_CXX_COMPILER_FLAG("-Wall" COMPILER_SUPPORTS_WALL)
+CHECK_CXX_COMPILER_FLAG("-Wall"      COMPILER_SUPPORTS_WALL)
+CHECK_CXX_COMPILER_FLAG("-Wextra"    COMPILER_SUPPORTS_WEXTRA)
 CHECK_CXX_COMPILER_FLAG("-Wpedantic" COMPILER_SUPPORTS_WPEDANTIC)
 
 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()
@@ -87,7 +94,7 @@ add_definitions(-DUNITTEST_FRAMEWORK_LIBRARY_EXIST)
 
 foreach(TEST_NAME ${TEST_NAMES})
     add_executable(${TEST_NAME} ${TEST_NAME}.cpp)
-    target_link_libraries(${TEST_NAME} ${Boost_UNIT_TEST_FRAMEWORK_LIBRARY})
+    target_link_libraries(${TEST_NAME} ${Boost_UNIT_TEST_FRAMEWORK_LIBRARY} toml11::toml11)
     target_include_directories(${TEST_NAME} PRIVATE ${Boost_INCLUDE_DIRS})
     add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME} WORKING_DIRECTORY ${PROJECT_BINARY_DIR})
 
@@ -104,3 +111,4 @@ endforeach(TEST_NAME)
 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)

tests/check_serialization.cpp

@@ -0,0 +1,57 @@
+#include "toml.hpp"
+#include <iostream>
+#include <iomanip>
+
+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)
+        {
+            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)
+        {
+            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

@@ -84,8 +84,8 @@ struct json_serializer
         {
             if(!is_first) {std::cout << ", ";}
             is_first = false;
-            std::cout << toml::format(toml::string(elem.first),
-                                      std::numeric_limits<std::size_t>::max());
+            std::cout << toml::format(toml::value(elem.first),
+                    std::numeric_limits<std::size_t>::max());
             std::cout << ':';
             toml::visit(*this, elem.second);
         }

tests/test_comments.cpp

@@ -0,0 +1,514 @@
+#define BOOST_TEST_MODULE "test_comments"
+#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>
+
+BOOST_AUTO_TEST_CASE(test_comment_before)
+{
+    {
+        const std::string file = u8R"(
+            # 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() == u8" comment for a.");
+        BOOST_TEST(b.comments().size()  == 1u);
+        BOOST_TEST(b.comments().front() == u8" comment for b.");
+    }
+    {
+        const std::string file = u8R"(
+            # 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() == u8" comment for a.");
+        BOOST_TEST(a.comments().back()  == u8" another comment for a.");
+        BOOST_TEST(b.comments().size()  == 2u);
+        BOOST_TEST(b.comments().front() == u8" comment for b.");
+        BOOST_TEST(b.comments().back()  == u8" also comment for b.");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_comment_inline)
+{
+    {
+        const std::string file = u8R"(
+            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() == u8" comment for a.");
+        BOOST_TEST(b.comments().size()  == 1u);
+        BOOST_TEST(b.comments().front() == u8" comment for b.");
+    }
+    {
+        const std::string file = u8R"(
+            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()  == u8" comment for a.");
+        BOOST_TEST(b.comments().size()   == 1u);
+        BOOST_TEST(b.comments().front()  == u8" this is a comment for b.");
+        BOOST_TEST(b0.comments().size()  == 1u);
+        BOOST_TEST(b0.comments().front() == u8" this is not a comment for b, but \"bar\"");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_comment_both)
+{
+    {
+        const std::string file = u8R"(
+            # 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() == u8" comment for a.");
+        BOOST_TEST(a.comments().back()  == u8" inline comment for a.");
+        BOOST_TEST(b.comments().size()  == 2u);
+        BOOST_TEST(b.comments().front() == u8" comment for b.");
+        BOOST_TEST(b.comments().back()  == u8" inline comment for b.");
+
+        BOOST_TEST(c.comments().size()  == 2u);
+        BOOST_TEST(c.comments().front() == u8" comment for c.");
+        BOOST_TEST(c.comments().back()  == u8" another comment for c.");
+
+        BOOST_TEST(c0.comments().size()  == 2u);
+        BOOST_TEST(c0.comments().front() == u8" comment for the first element.");
+        BOOST_TEST(c0.comments().back()  == u8" this also.");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_discard_comment)
+{
+    const std::string file = u8R"(
+        # 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(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 __cplusplus >= 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

@@ -11,47 +11,47 @@ 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 +59,20 @@ 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 +80,15 @@ 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 +97,18 @@ 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 +117,6 @@ 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

@@ -12,50 +12,19 @@
 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 +35,7 @@ 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 +46,7 @@ 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 +57,7 @@ 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 +66,7 @@ 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)
@@ -146,17 +75,7 @@ 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)
@@ -164,17 +83,7 @@ BOOST_AUTO_TEST_CASE(test_detect_inhomogeneous_array)
     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);
 }
 
 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 +1,30 @@
+#define BOOST_TEST_MODULE "test_expect"
+#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_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

@@ -6,6 +6,8 @@
 #include <boost/test/included/unit_test.hpp>
 #endif
 #include <toml.hpp>
+#include <deque>
+#include <map>
 
 namespace extlib
 {
@@ -54,63 +56,237 @@ struct into<extlib::foo>
 };
 } // 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}};
+    }
+};
+} // 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}};
+    }
+};
+} // toml
+
+// ---------------------------------------------------------------------------
 
 BOOST_AUTO_TEST_CASE(test_conversion_by_member_methods)
 {
-    const toml::value v{{"a", 42}, {"b", "baz"}};
+    {
+        const toml::value v{{"a", 42}, {"b", "baz"}};
 
-    const auto foo = toml::get<extlib::foo>(v);
-    BOOST_CHECK_EQUAL(foo.a, 42);
-    BOOST_CHECK_EQUAL(foo.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);
+        const toml::value v2(foo);
 
-    BOOST_CHECK_EQUAL(v, v2);
+        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 toml::value v{{"a", 42}, {"b", "baz"}};
 
-    const auto bar = toml::get<extlib::bar>(v);
-    BOOST_CHECK_EQUAL(bar.a, 42);
-    BOOST_CHECK_EQUAL(bar.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);
+        const toml::value v2(bar);
 
-    BOOST_CHECK_EQUAL(v, v2);
+        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_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 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_CHECK_EQUAL(foos.size()  , 4ul);
-    BOOST_CHECK_EQUAL(foos.at(0).a , 42);
-    BOOST_CHECK_EQUAL(foos.at(1).a , 43);
-    BOOST_CHECK_EQUAL(foos.at(2).a , 44);
-    BOOST_CHECK_EQUAL(foos.at(3).a , 45);
+        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_CHECK_EQUAL(foos.at(0).b , "baz");
-    BOOST_CHECK_EQUAL(foos.at(1).b , "qux");
-    BOOST_CHECK_EQUAL(foos.at(2).b , "quux");
-    BOOST_CHECK_EQUAL(foos.at(3).b , "foobar");
+        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_CHECK_EQUAL(bars.size()  , 4ul);
-    BOOST_CHECK_EQUAL(bars.at(0).a , 42);
-    BOOST_CHECK_EQUAL(bars.at(1).a , 43);
-    BOOST_CHECK_EQUAL(bars.at(2).a , 44);
-    BOOST_CHECK_EQUAL(bars.at(3).a , 45);
+        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_CHECK_EQUAL(bars.at(0).b , "baz");
-    BOOST_CHECK_EQUAL(bars.at(1).b , "qux");
-    BOOST_CHECK_EQUAL(bars.at(2).b , "quux");
-    BOOST_CHECK_EQUAL(bars.at(3).b , "foobar");
+        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");
+    }
 }
+

tests/test_find.cpp

@@ -0,0 +1,432 @@
+#define BOOST_TEST_MODULE "test_find"
+
+#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>
+#if __cplusplus >= 201703L
+#include <string_view>
+#endif
+#include <tuple>
+
+using test_value_types = std::tuple<
+    toml::value,
+    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)
+{
+    {
+        // 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"));
+    }
+}
+
+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));
+    }
+}
+
+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"));
+    }
+    {
+        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"));
+    }
+    {
+        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"));
+    }
+    {
+        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"));
+    }
+    {
+        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"));
+    }
+    {
+        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"));
+    }
+    {
+        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"));
+    }
+    {
+        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"));
+    }
+    {
+        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"));
+    }
+    {
+        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);
+    }
+    {
+        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);
+    }
+    {
+        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"));
+    }
+}
+
+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_AUTO_TEST_CASE_TEMPLATE(test_find_floating_type, value_type, test_value_types)
+{
+    {
+        value_type v{{"key", 3.14}};
+        BOOST_TEST(static_cast<float      >(3.14) == toml::find<float      >(v, "key"));
+        BOOST_TEST(static_cast<double     >(3.14) == toml::find<double     >(v, "key"));
+        BOOST_TEST(static_cast<long double>(3.14) == toml::find<long double>(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"));
+    }
+
+#if __cplusplus >= 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(static_cast<int>(42) == ary.at(0));
+    BOOST_TEST(static_cast<int>(54) == ary.at(1));
+    BOOST_TEST(static_cast<int>(69) == ary.at(2));
+    BOOST_TEST(static_cast<int>(72) == ary.at(3));
+
+    std::tuple<int, short, unsigned, long> tpl =
+        toml::find<std::tuple<int, short, unsigned, long>>(v, "key");
+    BOOST_TEST(static_cast<int     >(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_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_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);
+}
+
+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);
+}
+
+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));
+}
+
+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);
+}
+
+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);
+    }
+}
+

tests/test_find_or.cpp

@@ -0,0 +1,360 @@
+#define BOOST_TEST_MODULE "test_find_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>
+#include <tuple>
+#if __cplusplus >= 201703L
+#include <string_view>
+#endif
+
+using test_value_types = std::tuple<
+    toml::value,
+    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_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 = toml::table{{"num", 42}};
+        BOOST_TEST(42u == toml::find_or(v, "num", 0u));
+        BOOST_TEST(0u ==  toml::find_or(v, "foo", 0u));
+    }
+}
+
+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));
+        BOOST_TEST(static_cast<float>(double(3.14)) == toml::find_or(v2, "key", 2.71f));
+    }
+}
+
+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)));
+    }
+    // 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));
+    }
+}

tests/test_format_error.cpp

@@ -1,4 +1,4 @@
-#define BOOST_TEST_MODULE "test_value"
+#define BOOST_TEST_MODULE "test_format_error"
 #ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
 #include <boost/test/unit_test.hpp>
 #else

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

@@ -5,280 +5,284 @@
 #define BOOST_TEST_NO_LIB
 #include <boost/test/included/unit_test.hpp>
 #endif
-#include <toml/value.hpp>
-#include <toml/get.hpp>
+#include <toml.hpp>
 #include <map>
 #include <unordered_map>
 #include <list>
 #include <deque>
 #include <array>
+#include <tuple>
+#if __cplusplus >= 201703L
+#include <string_view>
+#endif
 
+using test_value_types = std::tuple<
+    toml::value,
+    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_get_exact)
+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::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::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::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::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::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_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_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::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::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));
     }
     {
-        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));
     }
     {
-        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));
     }
 }
 
-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_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);
+        BOOST_TEST(static_cast<float      >(3.14) == toml::get<float      >(v));
+        BOOST_TEST(static_cast<double     >(3.14) == toml::get<double     >(v));
+        BOOST_TEST(static_cast<long double>(3.14) == toml::get<long double>(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));
     }
     {
-        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));
     }
+
+#if __cplusplus >= 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(test_get_toml_array)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_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 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_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(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_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(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_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));
+    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_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(static_cast<int>(42) == ary.at(0));
+    BOOST_TEST(static_cast<int>(54) == ary.at(1));
+    BOOST_TEST(static_cast<int>(69) == ary.at(2));
+    BOOST_TEST(static_cast<int>(72) == ary.at(3));
 
     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(static_cast<int     >(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));
 
-    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));
+    const value_type p{3.14, 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);
+    BOOST_TEST(3.14 == pr.first);
+    BOOST_TEST(2.71 == pr.second);
 }
 
-BOOST_AUTO_TEST_CASE(test_get_toml_array_of_array)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_array_of_array, 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));
-
-    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"));
-
-    toml::value v(toml::array(2));
-    toml::get<toml::array>(v).at(0) = v1;
-    toml::get<toml::array>(v).at(1) = v2;
+    const value_type v1{42, 54, 69, 72};
+    const value_type v2{"foo", "bar", "baz"};
+    const value_type v{v1, 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_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_CHECK_EQUAL(p.second.at(0), "foo");
-    BOOST_CHECK_EQUAL(p.second.at(1), "bar");
-    BOOST_CHECK_EQUAL(p.second.at(2), "baz");
+    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::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_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_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_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(test_get_toml_table)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_table, value_type, test_value_types)
 {
-    toml::value v1(toml::table{
+    const value_type v1{
             {"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_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(test_get_toml_local_date)
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_local_date, value_type, test_value_types)
 {
-    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 +295,22 @@ 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 +325,13 @@ 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 +343,18 @@ 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 +366,14 @@ 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 +1,360 @@
+#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>
+#include <tuple>
+#if __cplusplus >= 201703L
+#include <string_view>
+#endif
+
+using test_value_types = std::tuple<
+    toml::value,
+    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_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_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));
+    }
+}
+
+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));
+    }
+}
+
+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);
+
+        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));
+    }
+}

tests/test_get_related_func.cpp

@@ -1,254 +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)
-{
-    // requires conversion int -> uint
-    {
-        toml::value v1(42);
-        toml::value v2(3.14);
-        BOOST_CHECK_EQUAL(42u, toml::get_or(v1, 0u));
-        BOOST_CHECK_EQUAL(0u,  toml::get_or(v2, 0u));
-    }
-
-    // exact toml type
-    {
-        toml::value v1(42);
-        toml::value v2(3.14);
-
-        toml::integer opt(0);
-        BOOST_CHECK_EQUAL(42, toml::get_or(v1, opt));
-        BOOST_CHECK_EQUAL(0,  toml::get_or(v2, opt));
-
-        toml::value v3("foobar");
-        toml::string s("bazqux");
-
-        BOOST_CHECK_EQUAL("foobar", toml::get_or(v3, s));
-        BOOST_CHECK_EQUAL("bazqux", toml::get_or(v1, s));
-
-    }
-
-    // std::string
-    {
-        toml::value v1("foobar");
-        toml::value v2(42);
-
-        std::string       s1("bazqux");
-        const std::string s2("bazqux");
-
-        BOOST_CHECK_EQUAL("foobar", toml::get_or(v1, s1));
-        BOOST_CHECK_EQUAL("bazqux", toml::get_or(v2, s1));
-
-        std::string& v1r = toml::get_or(v1, s1);
-        std::string& s1r = toml::get_or(v2, s1);
-
-        BOOST_CHECK_EQUAL("foobar", v1r);
-        BOOST_CHECK_EQUAL("bazqux", s1r);
-
-        BOOST_CHECK_EQUAL("foobar", toml::get_or(v1, s2));
-        BOOST_CHECK_EQUAL("bazqux", toml::get_or(v2, s2));
-
-        BOOST_CHECK_EQUAL("foobar", toml::get_or(v1, std::move(s1)));
-        BOOST_CHECK_EQUAL("bazqux", toml::get_or(v2, std::move(s1)));
-    }
-
-    // string literal
-    {
-        toml::value v1("foobar");
-        toml::value v2(42);
-
-        BOOST_CHECK_EQUAL("foobar", toml::get_or(v1, "bazqux"));
-        BOOST_CHECK_EQUAL("bazqux", toml::get_or(v2, "bazqux"));
-
-        const char* lit = "bazqux";
-        BOOST_CHECK_EQUAL("foobar", toml::get_or(v1, lit));
-        BOOST_CHECK_EQUAL("bazqux", toml::get_or(v2, lit));
-    }
-}
-
-BOOST_AUTO_TEST_CASE(test_find_or)
-{
-    // ========================================================================
-    // pass toml::value
-    //
-    // requires conversion int -> uint
-    {
-        toml::table v{{"num", 42}};
-        BOOST_CHECK_EQUAL(42u, toml::find_or(v, "num", 0u));
-        BOOST_CHECK_EQUAL(0u,  toml::find_or(v, "foo", 0u));
-    }
-    // exact toml type
-    {
-        toml::table v1{{"key", 42  }};
-        toml::table v2{{"key", 3.14}};
-        toml::table v3{{"not", "key"}};
-
-        toml::integer opt(0);
-        BOOST_CHECK_EQUAL(42, toml::find_or(v1, "key", opt));
-        BOOST_CHECK_EQUAL(0,  toml::find_or(v2, "key", opt));
-        BOOST_CHECK_EQUAL(0,  toml::find_or(v3, "key", opt));
-
-        toml::table v4{{"str", "foobar"}};
-        toml::string s("bazqux");
-
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(v4, "str", s));
-        BOOST_CHECK_EQUAL("bazqux", toml::find_or(v1, "str", s));
-    }
-    // std::string
-    {
-        toml::table v1{{"key", "foobar"}};
-        toml::table v2{{"key", 42}};
-
-        std::string       s1("bazqux");
-        const std::string s2("bazqux");
-
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(v1, "key", s1));
-        BOOST_CHECK_EQUAL("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_CHECK_EQUAL("foobar", v1r);
-        BOOST_CHECK_EQUAL("bazqux", s1r);
-
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(v1, "key", s2));
-        BOOST_CHECK_EQUAL("bazqux", toml::find_or(v2, "key", s2));
-
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(std::move(v1), "key", std::move(s1)));
-        s1 = "bazqux"; // restoring moved value
-        BOOST_CHECK_EQUAL("bazqux", toml::find_or(std::move(v2), "key", std::move(s1)));
-    }
-    // string literal
-    {
-        toml::table v1{{"key", "foobar"}};
-        toml::table v2{{"key",42}};
-
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(v1, "key", "bazqux"));
-        BOOST_CHECK_EQUAL("bazqux", toml::find_or(v2, "key", "bazqux"));
-
-        const char* lit = "bazqux";
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(v1, "key", lit));
-        BOOST_CHECK_EQUAL("bazqux", toml::find_or(v2, "key", lit));
-    }
-
-    // ========================================================================
-    // pass toml::value
-    //
-    // requires conversion int -> uint
-    {
-        toml::table v = toml::table{{"num", 42}};
-        BOOST_CHECK_EQUAL(42u, toml::find_or(v, "num", 0u));
-        BOOST_CHECK_EQUAL(0u,  toml::find_or(v, "foo", 0u));
-    }
-    // exact toml type
-    {
-        toml::value v1 = toml::table{{"key", 42  }};
-        toml::value v2 = toml::table{{"key", 3.14}};
-        toml::value v3 = toml::table{{"not", "key"}};
-
-        BOOST_CHECK_EQUAL(42, toml::find_or(v1, "key", toml::integer(0)));
-        BOOST_CHECK_EQUAL( 0, toml::find_or(v2, "key", toml::integer(0)));
-        BOOST_CHECK_EQUAL( 0, toml::find_or(v3, "key", toml::integer(0)));
-
-        toml::value v4 = toml::table{{"str", "foobar"}};
-        toml::string s("bazqux");
-
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(v4, "str", s));
-        BOOST_CHECK_EQUAL("bazqux", toml::find_or(v1, "str", s));
-    }
-    // std::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_CHECK_EQUAL("foobar", toml::find_or(v1, "key", s1));
-        BOOST_CHECK_EQUAL("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_CHECK_EQUAL("foobar", v1r);
-        BOOST_CHECK_EQUAL("bazqux", s1r);
-
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(v1, "key", s2));
-        BOOST_CHECK_EQUAL("bazqux", toml::find_or(v2, "key", s2));
-
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(std::move(v1), "key", std::move(s1)));
-        s1 = "bazqux"; // restoring moved value
-        BOOST_CHECK_EQUAL("bazqux", toml::find_or(std::move(v2), "key", std::move(s1)));
-    }
-    // string literal
-    {
-        toml::value v1 = toml::table{{"key", "foobar"}};
-        toml::value v2 = toml::table{{"key",42}};
-
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(v1, "key", "bazqux"));
-        BOOST_CHECK_EQUAL("bazqux", toml::find_or(v2, "key", "bazqux"));
-
-        const char* lit = "bazqux";
-        BOOST_CHECK_EQUAL("foobar", toml::find_or(v1, "key", lit));
-        BOOST_CHECK_EQUAL("bazqux", toml::find_or(v2, "key", lit));
-    }
-}
-
-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

@@ -10,17 +10,17 @@ do {                                                                           \
     const std::string expected(expct);                                         \
     toml::detail::location<std::string> 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);                                                                \
 /**/
@@ -30,6 +30,7 @@ do {                                                                           \
     const std::string token   (tkn);                                           \
     toml::detail::location<std::string> 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_literals.cpp

@@ -19,7 +19,7 @@ BOOST_AUTO_TEST_CASE(test_file_as_literal)
             b = "baz"
         )"_toml;
 
-        BOOST_CHECK_EQUAL(r, v);
+        BOOST_TEST(r == v);
     }
     {
         const toml::value r{
@@ -33,7 +33,7 @@ BOOST_AUTO_TEST_CASE(test_file_as_literal)
             b = "baz"
         )"_toml;
 
-        BOOST_CHECK_EQUAL(r, v);
+        BOOST_TEST(r == v);
     }
     {
         const toml::value r{
@@ -45,7 +45,7 @@ BOOST_AUTO_TEST_CASE(test_file_as_literal)
             b = "baz"
         )"_toml;
 
-        BOOST_CHECK_EQUAL(r, v);
+        BOOST_TEST(r == v);
     }
 }
 
@@ -57,31 +57,31 @@ BOOST_AUTO_TEST_CASE(test_value_as_literal)
         const toml::value v1 = u8"true"_toml;
         const toml::value v2 = u8"false"_toml;
 
-        BOOST_CHECK(v1.is_boolean());
-        BOOST_CHECK(v2.is_boolean());
-        BOOST_CHECK(toml::get<bool>(v1));
-        BOOST_CHECK(!toml::get<bool>(v2));
+        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_CHECK(v1.is_integer());
-        BOOST_CHECK(v2.is_integer());
-        BOOST_CHECK(v3.is_integer());
-        BOOST_CHECK_EQUAL(toml::get<toml::integer>(v1), 123456);
-        BOOST_CHECK_EQUAL(toml::get<toml::integer>(v2), 2);
-        BOOST_CHECK_EQUAL(toml::get<toml::integer>(v3), 0xDEADBEEF);
+        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_CHECK(v1.is_float());
-        BOOST_CHECK(v2.is_float());
-        BOOST_CHECK_CLOSE(toml::get<double>(v1), 3.1415,  0.00001);
-        BOOST_CHECK_CLOSE(toml::get<double>(v2), 6.02e23, 0.0001);
+        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;
@@ -89,65 +89,74 @@ BOOST_AUTO_TEST_CASE(test_value_as_literal)
         const toml::value v3 = u8R"("""foo""")"_toml;
         const toml::value v4 = u8R"('''foo''')"_toml;
 
-        BOOST_CHECK(v1.is_string());
-        BOOST_CHECK(v2.is_string());
-        BOOST_CHECK(v3.is_string());
-        BOOST_CHECK(v4.is_string());
-        BOOST_CHECK_EQUAL(toml::get<std::string>(v1), "foo");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(v2), "foo");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(v3), "foo");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(v4), "foo");
+        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 = u8R"([1,2,3])"_toml;
-
-        BOOST_CHECK(v1.is_array());
-        BOOST_CHECK((toml::get<std::vector<int>>(v1) == std::vector<int>{1,2,3}));
-
-        const toml::value v2 = u8R"([1,])"_toml;
-
-        BOOST_CHECK(v2.is_array());
-        BOOST_CHECK((toml::get<std::vector<int>>(v2) == std::vector<int>{1}));
-
-        const toml::value v3 = u8R"([[1,]])"_toml;
-        BOOST_CHECK(v3.is_array());
-        BOOST_CHECK((toml::get<std::vector<int>>(toml::get<toml::array>(v3).front()) == std::vector<int>{1}));
-
-        const toml::value v4 = u8R"([[1],])"_toml;
-        BOOST_CHECK(v4.is_array());
-        BOOST_CHECK((toml::get<std::vector<int>>(toml::get<toml::array>(v4).front()) == std::vector<int>{1}));
+        {
+            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_CHECK(v1.is_table());
-        BOOST_CHECK((toml::get<std::map<std::string,int>>(v1) ==
-                               std::map<std::string,int>{{"a", 42}}));
+        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_CHECK(v1.is_local_date());
-        BOOST_CHECK_EQUAL(toml::get<toml::local_date>(v1),
-                          toml::local_date(1979, toml::month_t::May, 27));
+        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_CHECK(v1.is_local_time());
-        BOOST_CHECK(toml::get<std::chrono::hours>(v1) == std::chrono::hours(12));
+        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_CHECK(v1.is_local_datetime());
-        BOOST_CHECK_EQUAL(toml::get<toml::local_datetime>(v1),
+        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_CHECK(v1.is_offset_datetime());
-        BOOST_CHECK_EQUAL(toml::get<toml::offset_datetime>(v1),
+        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

@@ -7,5 +7,5 @@ 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(data);
+    return read_a(toml::get<toml::table>(data));
 }

tests/test_parse_array.cpp

@@ -1,4 +1,4 @@
-#define BOOST_TEST_MODULE "parse_array_test"
+#define BOOST_TEST_MODULE "parse_array<toml::value>_test"
 #ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
 #include <boost/test/unit_test.hpp>
 #else
@@ -13,118 +13,118 @@ using namespace detail;
 
 BOOST_AUTO_TEST_CASE(test_oneline_array)
 {
-    TOML11_TEST_PARSE_EQUAL(parse_array, "[]", array());
+    TOML11_TEST_PARSE_EQUAL(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(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(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(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(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(parse_array<toml::value>, "[\n#comment\n]", 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,\n1,\n4,\n1,\n5]", a);
+        TOML11_TEST_PARSE_EQUAL(parse_array<toml::value>, "[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);
+        TOML11_TEST_PARSE_EQUAL(parse_array<toml::value>, "[\"foo\",\n\"bar\",\n\"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,#comment\n1,#comment\n4,#comment\n1,#comment\n5]", a);
+        TOML11_TEST_PARSE_EQUAL(parse_array<toml::value>, "[3,#comment\n1,#comment\n4,#comment\n1,#comment\n5]", 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);
+        TOML11_TEST_PARSE_EQUAL(parse_array<toml::value>, "[\"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<toml::value>, "[\n#comment\n]", 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,\n1,\n4,\n1,\n5]", toml::value(a));
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[3,\n1,\n4,\n1,\n5]", 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\",\n\"bar\",\n\"baz\"]", toml::value(a));
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\",\n\"bar\",\n\"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,#comment\n1,#comment\n4,#comment\n1,#comment\n5]", toml::value(a));
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[3,#comment\n1,#comment\n4,#comment\n1,#comment\n5]", toml::value(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));
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\",#comment\n\"b#r\",#comment\n\"b#z\"#comment\n]", toml::value(a));
     }
 }

tests/test_parse_aux.hpp

@@ -1,8 +1,7 @@
 #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)                               \
@@ -10,13 +9,13 @@ do {                                                                           \
     const std::string token(tkn);                                              \
     toml::detail::location<std::string> 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);                                                                \
 /**/
@@ -26,13 +25,13 @@ do {                                                                           \
     const std::string token(tkn);                                              \
     toml::detail::location<std::string> 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() == 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

@@ -19,6 +19,6 @@ 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

@@ -21,10 +21,10 @@ BOOST_AUTO_TEST_CASE(test_time)
 
 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)));
 }
 
 BOOST_AUTO_TEST_CASE(test_date)
@@ -34,7 +34,7 @@ BOOST_AUTO_TEST_CASE(test_date)
 }
 BOOST_AUTO_TEST_CASE(test_date_value)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value, "1979-05-27",
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1979-05-27",
                             value(toml::local_date(1979, toml::month_t::May, 27)));
 }
 
@@ -64,25 +64,25 @@ 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))));
 }
 
@@ -111,23 +111,23 @@ BOOST_AUTO_TEST_CASE(test_offset_datetime)
 
 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_file.cpp

@@ -8,73 +8,69 @@
 #include <toml.hpp>
 #include <iostream>
 #include <fstream>
-
+#include <map>
+#include <deque>
 
 BOOST_AUTO_TEST_CASE(test_example)
 {
     const auto data = toml::parse("toml/tests/example.toml");
 
-    BOOST_CHECK_EQUAL(toml::get<std::string>(data.at("title")), "TOML Example");
-    toml::Table owner = toml::get<toml::Table>(data.at("owner"));
+    BOOST_TEST(toml::find<std::string>(data, "title") == "TOML Example");
+    const auto& owner = toml::find(data, "owner");
     {
-        BOOST_CHECK_EQUAL(toml::get<std::string>(owner.at("name")), "Tom Preston-Werner");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(owner.at("organization")), "GitHub");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(owner.at("bio")),
+        BOOST_TEST(toml::find<std::string>(owner, "name") == "Tom Preston-Werner");
+        BOOST_TEST(toml::find<std::string>(owner, "organization") == "GitHub");
+        BOOST_TEST(toml::find<std::string>(owner, "bio") ==
                           "GitHub Cofounder & CEO\nLikes tater tots and beer.");
-        BOOST_CHECK_EQUAL(toml::get<toml::Datetime>(owner.at("dob")),
+        BOOST_TEST(toml::find<toml::offset_datetime>(owner, "dob") ==
                           toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
                                                 toml::local_time(7, 32, 0), toml::time_offset(0, 0)));
     }
 
-    toml::Table database = toml::get<toml::Table>(data.at("database"));
+    const auto& database = toml::find(data, "database");
     {
-        BOOST_CHECK_EQUAL(toml::get<std::string>(database.at("server")), "192.168.1.1");
+        BOOST_TEST(toml::find<std::string>(database, "server") == "192.168.1.1");
         const std::vector<int> expected_ports{8001, 8001, 8002};
-        BOOST_CHECK(toml::get<std::vector<int>>(database.at("ports")) == expected_ports);
-        BOOST_CHECK_EQUAL(toml::get<int>(database.at("connection_max")), 5000);
-        BOOST_CHECK_EQUAL(toml::get<bool>(database.at("enabled")), true);
+        BOOST_CHECK(toml::find<std::vector<int>>(database, "ports") == expected_ports);
+        BOOST_TEST(toml::find<int >(database, "connection_max") == 5000);
+        BOOST_TEST(toml::find<bool>(database, "enabled") == true);
     }
 
-    toml::Table servers = toml::get<toml::Table>(data.at("servers"));
+    const auto& servers = toml::find(data, "servers");
     {
-        toml::Table alpha = toml::get<toml::Table>(servers.at("alpha"));
-        BOOST_CHECK_EQUAL(toml::get<std::string>(alpha.at("ip")), "10.0.0.1");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(alpha.at("dc")), "eqdc10");
+        toml::table alpha = toml::find<toml::table>(servers, "alpha");
+        BOOST_TEST(toml::get<std::string>(alpha.at("ip")) == "10.0.0.1");
+        BOOST_TEST(toml::get<std::string>(alpha.at("dc")) == "eqdc10");
 
-        toml::Table beta = toml::get<toml::Table>(servers.at("beta"));
-        BOOST_CHECK_EQUAL(toml::get<std::string>(beta.at("ip")), "10.0.0.2");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(beta.at("dc")), "eqdc10");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(beta.at("country")), "\xE4\xB8\xAD\xE5\x9B\xBD");
+        toml::table beta = toml::find<toml::table>(servers, "beta");
+        BOOST_TEST(toml::get<std::string>(beta.at("ip")) == "10.0.0.2");
+        BOOST_TEST(toml::get<std::string>(beta.at("dc")) == "eqdc10");
+        BOOST_TEST(toml::get<std::string>(beta.at("country")) == "\xE4\xB8\xAD\xE5\x9B\xBD");
     }
 
-    toml::Table clients = toml::get<toml::Table>(data.at("clients"));
+    const auto& clients = toml::find(data, "clients");
     {
-        toml::Array clients_data = toml::get<toml::Array>(clients.at("data"));
+        toml::array clients_data = toml::find<toml::array>(clients, "data");
+
         std::vector<std::string> expected_name{"gamma", "delta"};
-        BOOST_CHECK(toml::get<std::vector<std::string>>(clients_data.at(0)) ==
-                    expected_name);
+        BOOST_CHECK(toml::get<std::vector<std::string>>(clients_data.at(0)) == expected_name);
+
         std::vector<int> expected_number{1, 2};
-        BOOST_CHECK(toml::get<std::vector<int>>(clients_data.at(1)) ==
-                    expected_number);
+        BOOST_CHECK(toml::get<std::vector<int>>(clients_data.at(1)) == expected_number);
+
         std::vector<std::string> expected_hosts{"alpha", "omega"};
-        BOOST_CHECK(toml::get<std::vector<std::string>>(clients.at("hosts")) ==
-                    expected_hosts);
+        BOOST_CHECK(toml::find<std::vector<std::string>>(clients, "hosts") == expected_hosts);
     }
 
-    std::vector<toml::Table> products =
-        toml::get<std::vector<toml::Table>>(data.at("products"));
+    std::vector<toml::table> products =
+        toml::find<std::vector<toml::table>>(data, "products");
     {
-        BOOST_CHECK_EQUAL(toml::get<std::string>(products.at(0).at("name")),
-                          "Hammer");
-        BOOST_CHECK_EQUAL(toml::get<std::int64_t>(products.at(0).at("sku")),
-                          738594937);
+        BOOST_TEST(toml::get<std::string>(products.at(0).at("name")) == "Hammer");
+        BOOST_TEST(toml::get<std::int64_t>(products.at(0).at("sku")) == 738594937);
 
-        BOOST_CHECK_EQUAL(toml::get<std::string>(products.at(1).at("name")),
-                          "Nail");
-        BOOST_CHECK_EQUAL(toml::get<std::int64_t>(products.at(1).at("sku")),
-                          284758393);
-        BOOST_CHECK_EQUAL(toml::get<std::string>(products.at(1).at("color")),
-                          "gray");
+        BOOST_TEST(toml::get<std::string>(products.at(1).at("name")) == "Nail");
+        BOOST_TEST(toml::get<std::int64_t>(products.at(1).at("sku")) == 284758393);
+        BOOST_TEST(toml::get<std::string>(products.at(1).at("color")) == "gray");
     }
 }
 
@@ -83,42 +79,194 @@ BOOST_AUTO_TEST_CASE(test_example_stream)
     std::ifstream ifs("toml/tests/example.toml");
     const auto data = toml::parse(ifs);
 
-    BOOST_CHECK_EQUAL(toml::get<std::string>(data.at("title")), "TOML Example");
-    toml::Table owner = toml::get<toml::Table>(data.at("owner"));
+    BOOST_TEST(toml::find<std::string>(data, "title") == "TOML Example");
+    const auto& owner = toml::find(data, "owner");
     {
-        BOOST_CHECK_EQUAL(toml::get<std::string>(owner.at("name")), "Tom Preston-Werner");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(owner.at("organization")), "GitHub");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(owner.at("bio")),
+        BOOST_TEST(toml::find<std::string>(owner, "name") == "Tom Preston-Werner");
+        BOOST_TEST(toml::find<std::string>(owner, "organization") == "GitHub");
+        BOOST_TEST(toml::find<std::string>(owner, "bio") ==
                           "GitHub Cofounder & CEO\nLikes tater tots and beer.");
-        BOOST_CHECK_EQUAL(toml::get<toml::Datetime>(owner.at("dob")),
+        BOOST_TEST(toml::find<toml::offset_datetime>(owner, "dob") ==
                           toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
                                                 toml::local_time(7, 32, 0), toml::time_offset(0, 0)));
     }
 
-    toml::Table database = toml::get<toml::Table>(data.at("database"));
+    const auto& database = toml::find(data, "database");
     {
-        BOOST_CHECK_EQUAL(toml::get<std::string>(database.at("server")), "192.168.1.1");
+        BOOST_TEST(toml::find<std::string>(database, "server") == "192.168.1.1");
         const std::vector<int> expected_ports{8001, 8001, 8002};
-        BOOST_CHECK(toml::get<std::vector<int>>(database.at("ports")) == expected_ports);
-        BOOST_CHECK_EQUAL(toml::get<int>(database.at("connection_max")), 5000);
-        BOOST_CHECK_EQUAL(toml::get<bool>(database.at("enabled")), true);
+        BOOST_CHECK(toml::find<std::vector<int>>(database, "ports") == expected_ports);
+        BOOST_TEST(toml::find<int >(database, "connection_max") == 5000);
+        BOOST_TEST(toml::find<bool>(database, "enabled") == true);
     }
 
-    toml::Table servers = toml::get<toml::Table>(data.at("servers"));
+    const auto& servers = toml::find(data, "servers");
     {
-        toml::Table alpha = toml::get<toml::Table>(servers.at("alpha"));
-        BOOST_CHECK_EQUAL(toml::get<std::string>(alpha.at("ip")), "10.0.0.1");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(alpha.at("dc")), "eqdc10");
+        toml::table alpha = toml::find<toml::table>(servers, "alpha");
+        BOOST_TEST(toml::get<std::string>(alpha.at("ip")) == "10.0.0.1");
+        BOOST_TEST(toml::get<std::string>(alpha.at("dc")) == "eqdc10");
 
-        toml::Table beta = toml::get<toml::Table>(servers.at("beta"));
-        BOOST_CHECK_EQUAL(toml::get<std::string>(beta.at("ip")), "10.0.0.2");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(beta.at("dc")), "eqdc10");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(beta.at("country")), "\xE4\xB8\xAD\xE5\x9B\xBD");
+        toml::table beta = toml::find<toml::table>(servers, "beta");
+        BOOST_TEST(toml::get<std::string>(beta.at("ip")) == "10.0.0.2");
+        BOOST_TEST(toml::get<std::string>(beta.at("dc")) == "eqdc10");
+        BOOST_TEST(toml::get<std::string>(beta.at("country")) == "\xE4\xB8\xAD\xE5\x9B\xBD");
     }
 
-    toml::Table clients = toml::get<toml::Table>(data.at("clients"));
+    const auto& clients = toml::find(data, "clients");
     {
-        toml::Array clients_data = toml::get<toml::Array>(clients.at("data"));
+        toml::array clients_data = toml::find<toml::array>(clients, "data");
+        std::vector<std::string> expected_name{"gamma", "delta"};
+        BOOST_CHECK(toml::get<std::vector<std::string>>(clients_data.at(0)) == expected_name);
+
+        std::vector<int> expected_number{1, 2};
+        BOOST_CHECK(toml::get<std::vector<int>>(clients_data.at(1)) == expected_number);
+
+        std::vector<std::string> expected_hosts{"alpha", "omega"};
+        BOOST_CHECK(toml::find<std::vector<std::string>>(clients, "hosts") == expected_hosts);
+    }
+
+    std::vector<toml::table> products =
+        toml::find<std::vector<toml::table>>(data, "products");
+    {
+        BOOST_TEST(toml::get<std::string>(products.at(0).at("name")) ==
+                          "Hammer");
+        BOOST_TEST(toml::get<std::int64_t>(products.at(0).at("sku")) ==
+                          738594937);
+
+        BOOST_TEST(toml::get<std::string>(products.at(1).at("name")) ==
+                          "Nail");
+        BOOST_TEST(toml::get<std::int64_t>(products.at(1).at("sku")) ==
+                          284758393);
+        BOOST_TEST(toml::get<std::string>(products.at(1).at("color")) ==
+                          "gray");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_fruit)
+{
+    const auto data = toml::parse("toml/tests/fruit.toml");
+    const auto blah = toml::find<toml::array>(toml::find(data, "fruit"), "blah");
+    BOOST_TEST(toml::find<std::string>(blah.at(0), "name") == "apple");
+    BOOST_TEST(toml::find<std::string>(blah.at(1), "name") == "banana");
+    {
+        const auto physical = toml::find(blah.at(0), "physical");
+        BOOST_TEST(toml::find<std::string>(physical, "color") == "red");
+        BOOST_TEST(toml::find<std::string>(physical, "shape") == "round");
+    }
+    {
+        const auto physical = toml::find(blah.at(1), "physical");
+        BOOST_TEST(toml::find<std::string>(physical, "color") == "yellow");
+        BOOST_TEST(toml::find<std::string>(physical, "shape") == "bent");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_hard_example)
+{
+    const auto data = toml::parse("toml/tests/hard_example.toml");
+    const auto the = toml::find(data, "the");
+    BOOST_TEST(toml::find<std::string>(the, "test_string") ==
+                      "You'll hate me after this - #");
+
+    const auto hard = toml::find(the, "hard");
+    const std::vector<std::string> expected_the_hard_test_array{"] ", " # "};
+    BOOST_CHECK(toml::find<std::vector<std::string>>(hard, "test_array") ==
+                expected_the_hard_test_array);
+    const std::vector<std::string> expected_the_hard_test_array2{
+        "Test #11 ]proved that", "Experiment #9 was a success"};
+    BOOST_CHECK(toml::find<std::vector<std::string>>(hard, "test_array2") ==
+                expected_the_hard_test_array2);
+    BOOST_TEST(toml::find<std::string>(hard, "another_test_string") ==
+                      " Same thing, but with a string #");
+    BOOST_TEST(toml::find<std::string>(hard, "harder_test_string") ==
+                      " And when \"'s are in the string, along with # \"");
+
+    const auto bit = toml::find(hard, "bit#");
+    BOOST_TEST(toml::find<std::string>(bit, "what?") ==
+                      "You don't think some user won't do that?");
+    const std::vector<std::string> expected_multi_line_array{"]"};
+    BOOST_CHECK(toml::find<std::vector<std::string>>(bit, "multi_line_array") ==
+                expected_multi_line_array);
+}
+BOOST_AUTO_TEST_CASE(test_hard_example_comment)
+{
+    const auto data = toml::parse<toml::preserve_comments>("toml/tests/hard_example.toml");
+    const auto the = toml::find(data, "the");
+    BOOST_TEST(toml::find<std::string>(the, "test_string") ==
+                      "You'll hate me after this - #");
+
+    const auto hard = toml::find(the, "hard");
+    const std::vector<std::string> expected_the_hard_test_array{"] ", " # "};
+    BOOST_CHECK(toml::find<std::vector<std::string>>(hard, "test_array") ==
+                expected_the_hard_test_array);
+    const std::vector<std::string> expected_the_hard_test_array2{
+        "Test #11 ]proved that", "Experiment #9 was a success"};
+    BOOST_CHECK(toml::find<std::vector<std::string>>(hard, "test_array2") ==
+                expected_the_hard_test_array2);
+    BOOST_TEST(toml::find<std::string>(hard, "another_test_string") ==
+                      " Same thing, but with a string #");
+    BOOST_TEST(toml::find<std::string>(hard, "harder_test_string") ==
+                      " And when \"'s are in the string, along with # \"");
+
+    const auto bit = toml::find(hard, "bit#");
+    BOOST_TEST(toml::find<std::string>(bit, "what?") ==
+                      "You don't think some user won't do that?");
+    const std::vector<std::string> expected_multi_line_array{"]"};
+    BOOST_CHECK(toml::find<std::vector<std::string>>(bit, "multi_line_array") ==
+                expected_multi_line_array);
+}
+
+
+BOOST_AUTO_TEST_CASE(test_example_preserve_comment)
+{
+    const auto data = toml::parse<toml::preserve_comments>("toml/tests/example.toml");
+
+    BOOST_TEST(toml::find<std::string>(data, "title") == "TOML Example");
+    const auto& owner = toml::find(data, "owner");
+    {
+        BOOST_TEST(toml::find<std::string>(owner, "name") == "Tom Preston-Werner");
+        BOOST_TEST(toml::find<std::string>(owner, "organization") == "GitHub");
+        BOOST_TEST(toml::find<std::string>(owner, "bio") ==
+                          "GitHub Cofounder & CEO\nLikes tater tots and beer.");
+        BOOST_TEST(toml::find<toml::offset_datetime>(owner, "dob") ==
+                          toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
+                                                toml::local_time(7, 32, 0), toml::time_offset(0, 0)));
+        BOOST_TEST(toml::find(owner, "dob").comments().at(0) ==
+                          " First class dates? Why not?");
+    }
+
+    const auto& database = toml::find(data, "database");
+    {
+        BOOST_TEST(toml::find<std::string>(database, "server") == "192.168.1.1");
+        const std::vector<int> expected_ports{8001, 8001, 8002};
+        BOOST_CHECK(toml::find<std::vector<int>>(database, "ports") == expected_ports);
+        BOOST_TEST(toml::find<int >(database, "connection_max") == 5000);
+        BOOST_TEST(toml::find<bool>(database, "enabled") == true);
+    }
+
+    const auto& servers = toml::find(data, "servers");
+    {
+        const auto& alpha = toml::find(servers, "alpha");
+        BOOST_TEST(alpha.comments().at(0) ==
+            " You can indent as you please. Tabs or spaces. TOML don't care.");
+        BOOST_TEST(toml::find<std::string>(alpha, "ip") == "10.0.0.1");
+        BOOST_TEST(toml::find<std::string>(alpha, "dc") == "eqdc10");
+
+        const auto& beta = toml::find(servers, "beta");
+        BOOST_TEST(toml::find<std::string>(beta, "ip") == "10.0.0.2");
+        BOOST_TEST(toml::find<std::string>(beta, "dc") == "eqdc10");
+        BOOST_TEST(toml::find<std::string>(beta, "country") ==
+                          "\xE4\xB8\xAD\xE5\x9B\xBD");
+        BOOST_TEST(toml::find(beta, "country").comments().at(0) ==
+                          " This should be parsed as UTF-8");
+    }
+
+    const auto& clients = toml::find(data, "clients");
+    {
+        BOOST_TEST(toml::find(clients, "data").comments().at(0) ==
+                " just an update to make sure parsers support it");
+
+
+        toml::array clients_data = toml::find<toml::array>(clients, "data");
         std::vector<std::string> expected_name{"gamma", "delta"};
         BOOST_CHECK(toml::get<std::vector<std::string>>(clients_data.at(0)) ==
                     expected_name);
@@ -126,73 +274,118 @@ BOOST_AUTO_TEST_CASE(test_example_stream)
         BOOST_CHECK(toml::get<std::vector<int>>(clients_data.at(1)) ==
                     expected_number);
         std::vector<std::string> expected_hosts{"alpha", "omega"};
-        BOOST_CHECK(toml::get<std::vector<std::string>>(clients.at("hosts")) ==
+        BOOST_CHECK(toml::find<std::vector<std::string>>(clients, "hosts") ==
                     expected_hosts);
+
+        BOOST_TEST(toml::find(clients, "hosts").comments().at(0) ==
+                    " Line breaks are OK when inside arrays");
     }
 
-    std::vector<toml::Table> products =
-        toml::get<std::vector<toml::Table>>(data.at("products"));
+    std::vector<toml::table> products =
+        toml::find<std::vector<toml::table>>(data, "products");
     {
-        BOOST_CHECK_EQUAL(toml::get<std::string>(products.at(0).at("name")),
+        BOOST_TEST(toml::get<std::string>(products.at(0).at("name")) ==
                           "Hammer");
-        BOOST_CHECK_EQUAL(toml::get<std::int64_t>(products.at(0).at("sku")),
+        BOOST_TEST(toml::get<std::int64_t>(products.at(0).at("sku")) ==
                           738594937);
 
-        BOOST_CHECK_EQUAL(toml::get<std::string>(products.at(1).at("name")),
+        BOOST_TEST(toml::get<std::string>(products.at(1).at("name")) ==
                           "Nail");
-        BOOST_CHECK_EQUAL(toml::get<std::int64_t>(products.at(1).at("sku")),
+        BOOST_TEST(toml::get<std::int64_t>(products.at(1).at("sku")) ==
                           284758393);
-        BOOST_CHECK_EQUAL(toml::get<std::string>(products.at(1).at("color")),
+        BOOST_TEST(toml::get<std::string>(products.at(1).at("color")) ==
                           "gray");
     }
 }
 
-
-BOOST_AUTO_TEST_CASE(test_fruit)
+BOOST_AUTO_TEST_CASE(test_example_preserve_stdmap_stddeque)
 {
-    const auto data = toml::parse("toml/tests/fruit.toml");
-    const auto blah = toml::get<std::vector<toml::Table>>(
-                      toml::get<toml::Table>(data.at("fruit")).at("blah"));
-    BOOST_CHECK_EQUAL(toml::get<std::string>(blah.at(0).at("name")), "apple");
-    BOOST_CHECK_EQUAL(toml::get<std::string>(blah.at(1).at("name")), "banana");
+    const auto data = toml::parse<toml::preserve_comments, std::map, std::deque
+          >("toml/tests/example.toml");
+
+    static_assert(std::is_same<typename decltype(data)::table_type,
+            std::map<toml::key, typename std::remove_cv<decltype(data)>::type>
+            >::value, "");
+    static_assert(std::is_same<typename decltype(data)::array_type,
+            std::deque<typename std::remove_cv<decltype(data)>::type>
+            >::value, "");
+
+    BOOST_TEST(toml::find<std::string>(data, "title") == "TOML Example");
+    const auto& owner = toml::find(data, "owner");
     {
-        const auto physical = toml::get<toml::Table>(blah.at(0).at("physical"));
-        BOOST_CHECK_EQUAL(toml::get<std::string>(physical.at("color")), "red");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(physical.at("shape")), "round");
+        BOOST_TEST(toml::find<std::string>(owner, "name") == "Tom Preston-Werner");
+        BOOST_TEST(toml::find<std::string>(owner, "organization") == "GitHub");
+        BOOST_TEST(toml::find<std::string>(owner, "bio") ==
+                          "GitHub Cofounder & CEO\nLikes tater tots and beer.");
+        BOOST_TEST(toml::find<toml::offset_datetime>(owner, "dob") ==
+                          toml::offset_datetime(toml::local_date(1979, toml::month_t::May, 27),
+                                                toml::local_time(7, 32, 0), toml::time_offset(0, 0)));
+        BOOST_TEST(toml::find(owner, "dob").comments().at(0) ==
+                          " First class dates? Why not?");
     }
+
+    const auto& database = toml::find(data, "database");
     {
-        const auto physical = toml::get<toml::Table>(blah.at(1).at("physical"));
-        BOOST_CHECK_EQUAL(toml::get<std::string>(physical.at("color")), "yellow");
-        BOOST_CHECK_EQUAL(toml::get<std::string>(physical.at("shape")), "bent");
+        BOOST_TEST(toml::find<std::string>(database, "server") == "192.168.1.1");
+        const std::vector<int> expected_ports{8001, 8001, 8002};
+        BOOST_CHECK(toml::find<std::vector<int>>(database, "ports") == expected_ports);
+        BOOST_TEST(toml::find<int >(database, "connection_max") == 5000);
+        BOOST_TEST(toml::find<bool>(database, "enabled") == true);
     }
-}
 
-BOOST_AUTO_TEST_CASE(test_hard_example)
-{
-    const auto data = toml::parse("toml/tests/hard_example.toml");
-    const auto the = toml::get<toml::Table>(data.at("the"));
-    BOOST_CHECK_EQUAL(toml::get<std::string>(the.at("test_string")),
-                      "You'll hate me after this - #");
+    const auto& servers = toml::find(data, "servers");
+    {
+        const auto& alpha = toml::find(servers, "alpha");
+        BOOST_TEST(alpha.comments().at(0) ==
+            " You can indent as you please. Tabs or spaces. TOML don't care.");
+        BOOST_TEST(toml::find<std::string>(alpha, "ip") == "10.0.0.1");
+        BOOST_TEST(toml::find<std::string>(alpha, "dc") == "eqdc10");
 
-    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{
-        "Test #11 ]proved that", "Experiment #9 was a success"};
-    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")),
-                      " Same thing, but with a string #");
-    BOOST_CHECK_EQUAL(toml::get<std::string>(hard.at("harder_test_string")),
-                      " And when \"'s are in the string, along with # \"");
+        const auto& beta = toml::find(servers, "beta");
+        BOOST_TEST(toml::find<std::string>(beta, "ip") == "10.0.0.2");
+        BOOST_TEST(toml::find<std::string>(beta, "dc") == "eqdc10");
+        BOOST_TEST(toml::find<std::string>(beta, "country") ==
+                          "\xE4\xB8\xAD\xE5\x9B\xBD");
+        BOOST_TEST(toml::find(beta, "country").comments().at(0) ==
+                          " This should be parsed as UTF-8");
+    }
 
-    const auto bit = toml::get<toml::Table>(hard.at("bit#"));
-    BOOST_CHECK_EQUAL(toml::get<std::string>(bit.at("what?")),
-                      "You don't think some user won't do that?");
-    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);
+    const auto& clients = toml::find(data, "clients");
+    {
+        BOOST_TEST(toml::find(clients, "data").comments().at(0) ==
+                " just an update to make sure parsers support it");
+
+
+        toml::array clients_data = toml::find<toml::array>(clients, "data");
+        std::vector<std::string> expected_name{"gamma", "delta"};
+        BOOST_CHECK(toml::get<std::vector<std::string>>(clients_data.at(0)) ==
+                    expected_name);
+        std::vector<int> expected_number{1, 2};
+        BOOST_CHECK(toml::get<std::vector<int>>(clients_data.at(1)) ==
+                    expected_number);
+        std::vector<std::string> expected_hosts{"alpha", "omega"};
+        BOOST_CHECK(toml::find<std::vector<std::string>>(clients, "hosts") ==
+                    expected_hosts);
+
+        BOOST_TEST(toml::find(clients, "hosts").comments().at(0) ==
+                    " Line breaks are OK when inside arrays");
+    }
+
+    std::vector<toml::table> products =
+        toml::find<std::vector<toml::table>>(data, "products");
+    {
+        BOOST_TEST(toml::get<std::string>(products.at(0).at("name")) ==
+                          "Hammer");
+        BOOST_TEST(toml::get<std::int64_t>(products.at(0).at("sku")) ==
+                          738594937);
+
+        BOOST_TEST(toml::get<std::string>(products.at(1).at("name")) ==
+                          "Nail");
+        BOOST_TEST(toml::get<std::int64_t>(products.at(1).at("sku")) ==
+                          284758393);
+        BOOST_TEST(toml::get<std::string>(products.at(1).at("color")) ==
+                          "gray");
+    }
 }
 
 // ---------------------------------------------------------------------------
@@ -210,8 +403,8 @@ BOOST_AUTO_TEST_CASE(test_file_with_BOM)
         std::istringstream iss(table);
         const auto data = toml::parse(iss, "test_file_with_BOM.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -226,8 +419,8 @@ BOOST_AUTO_TEST_CASE(test_file_with_BOM)
         }
         const auto data = toml::parse("tmp.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -239,8 +432,8 @@ BOOST_AUTO_TEST_CASE(test_file_with_BOM)
         std::istringstream iss(table);
         const auto data = toml::parse(iss, "test_file_with_BOM_CRLF.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -254,12 +447,12 @@ BOOST_AUTO_TEST_CASE(test_file_with_BOM)
             // value will be "\r\r\n". To avoid the additional "\r", use binary
             // mode.
             std::ofstream ofs("tmp.toml", std::ios_base::binary);
-            ofs.write(table.data(), table.size());
+            ofs.write(table.data(), static_cast<std::streamsize>(table.size()));
         }
         const auto data = toml::parse("tmp.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 }
 
@@ -275,8 +468,8 @@ BOOST_AUTO_TEST_CASE(test_file_without_newline_at_the_end_of_file)
         const auto data = toml::parse(iss,
                 "test_file_without_newline_at_the_end_of_file.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -288,8 +481,8 @@ BOOST_AUTO_TEST_CASE(test_file_without_newline_at_the_end_of_file)
         const auto data = toml::parse(iss,
                 "test_file_without_newline_at_the_end_of_file_CRLF.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 
     {
@@ -302,8 +495,8 @@ BOOST_AUTO_TEST_CASE(test_file_without_newline_at_the_end_of_file)
         const auto data = toml::parse(iss,
                 "test_file_without_newline_at_the_end_of_file_comment.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -315,8 +508,8 @@ BOOST_AUTO_TEST_CASE(test_file_without_newline_at_the_end_of_file)
         const auto data = toml::parse(iss,
                 "test_file_without_newline_at_the_end_of_file_comment.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 
     {
@@ -329,8 +522,8 @@ BOOST_AUTO_TEST_CASE(test_file_without_newline_at_the_end_of_file)
         const auto data = toml::parse(iss,
                 "test_file_without_newline_at_the_end_of_file_ws.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -342,8 +535,8 @@ BOOST_AUTO_TEST_CASE(test_file_without_newline_at_the_end_of_file)
         const auto data = toml::parse(iss,
                 "test_file_without_newline_at_the_end_of_file_ws.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 }
 
@@ -362,8 +555,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_comment)
         const auto data = toml::parse(iss,
                 "test_files_end_with_comment.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -377,8 +570,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_comment)
         const auto data = toml::parse(iss,
                 "test_files_end_with_comment.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 
     // comment w/ newline
@@ -394,8 +587,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_comment)
         const auto data = toml::parse(iss,
                 "test_files_end_with_comment.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -409,8 +602,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_comment)
         const auto data = toml::parse(iss,
                 "test_files_end_with_comment.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 
     // CRLF version
@@ -426,8 +619,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_comment)
         const auto data = toml::parse(iss,
                 "test_files_end_with_comment.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -441,8 +634,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_comment)
         const auto data = toml::parse(iss,
                 "test_files_end_with_comment.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -455,8 +648,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_comment)
         const auto data = toml::parse(iss,
                 "test_files_end_with_comment.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -470,8 +663,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_comment)
         const auto data = toml::parse(iss,
                 "test_files_end_with_comment.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 }
 
@@ -489,8 +682,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -504,8 +697,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 
     // with whitespaces
@@ -521,8 +714,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -536,8 +729,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -551,8 +744,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -566,8 +759,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 
     // with whitespaces but no newline
@@ -582,8 +775,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 
 
@@ -600,8 +793,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -615,8 +808,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 
     // with whitespaces
@@ -632,8 +825,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -647,8 +840,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -662,8 +855,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -677,8 +870,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
     {
         const std::string table(
@@ -691,7 +884,8 @@ BOOST_AUTO_TEST_CASE(test_files_end_with_empty_lines)
         const auto data = toml::parse(iss,
                 "test_files_end_with_newline.toml");
 
-        BOOST_CHECK_EQUAL(toml::get <std::string>(data.at("key")), "value");
-        BOOST_CHECK_EQUAL(toml::find<std::string>(data.at("table"), "key"), "value");
+        BOOST_TEST(toml::find<std::string>(data, "key") == "value");
+        BOOST_TEST(toml::find<std::string>(toml::find(data, "table"), "key") == "value");
     }
 }
+

tests/test_parse_floating.cpp

@@ -32,20 +32,20 @@ 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)
@@ -72,24 +72,24 @@ BOOST_AUTO_TEST_CASE(test_exponential)
 
 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));
 }
 BOOST_AUTO_TEST_CASE(test_fe)
 {
@@ -99,9 +99,9 @@ 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));
 }
 
 BOOST_AUTO_TEST_CASE(test_inf)

tests/test_parse_inline_table.cpp

@@ -13,36 +13,36 @@ using namespace detail;
 
 BOOST_AUTO_TEST_CASE(test_inline_table)
 {
-    TOML11_TEST_PARSE_EQUAL(parse_inline_table, "{}", table());
+    TOML11_TEST_PARSE_EQUAL(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(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(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));
     }
 }

tests/test_parse_integer.cpp

@@ -25,14 +25,14 @@ 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 +50,15 @@ 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 +70,9 @@ 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 +85,8 @@ 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));
 }

tests/test_parse_string.cpp

@@ -29,16 +29,16 @@ 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));
 }
@@ -73,25 +73,25 @@ BOOST_AUTO_TEST_CASE(test_basic_string)
 
 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));
 }
@@ -108,10 +108,10 @@ BOOST_AUTO_TEST_CASE(test_ml_basic_string)
 
 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));
 }
@@ -134,16 +134,16 @@ 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));
 }
@@ -160,10 +160,10 @@ BOOST_AUTO_TEST_CASE(test_ml_literal_string)
 
 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));
 }

tests/test_parse_table.cpp

@@ -21,13 +21,13 @@ BOOST_AUTO_TEST_CASE(test_normal_table)
         );
     location<std::string> 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)
@@ -38,13 +38,13 @@ BOOST_AUTO_TEST_CASE(test_nested_table)
         );
     location<std::string> 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_unicode.cpp

@@ -14,11 +14,11 @@ 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")),
+    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);
@@ -28,13 +28,13 @@ 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")) ==
@@ -45,11 +45,11 @@ 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")),
+    const auto the = toml::find<toml::table>(data, "the");
+    BOOST_TEST(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 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);
@@ -58,13 +58,13 @@ BOOST_AUTO_TEST_CASE(test_hard_example_unicode)
             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")),
+    BOOST_TEST(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")),
+    BOOST_TEST(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?"))),
+    const auto bit = toml::get<toml::table>(hard.at(std::string(u8"βïƭ#")));
+    BOOST_TEST(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")) ==

tests/test_result.cpp

@@ -8,49 +8,49 @@ 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 +59,54 @@ 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 +119,10 @@ 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 +132,10 @@ 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 +144,10 @@ 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 +157,10 @@ 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 +173,10 @@ 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 +186,10 @@ 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 +197,10 @@ 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 +210,10 @@ 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 +226,7 @@ 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 +236,7 @@ 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 +245,7 @@ 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 +255,7 @@ BOOST_AUTO_TEST_CASE(test_map_or_else)
                     return *i;
                 }, 54);
 
-        BOOST_CHECK_EQUAL(mapped, 54);
+        BOOST_TEST(mapped == 54);
     }
 }
 
@@ -268,7 +268,7 @@ 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 +278,7 @@ 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 +287,7 @@ 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 +297,7 @@ BOOST_AUTO_TEST_CASE(test_map_err_or_else)
                     return i + i;
                 }, "foobar");
 
-        BOOST_CHECK_EQUAL(mapped, "hogehoge");
+        BOOST_TEST(mapped == "hogehoge");
     }
 }
 
@@ -311,10 +311,10 @@ 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 +324,10 @@ 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 +336,10 @@ 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 +349,10 @@ 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 +365,10 @@ 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 +378,10 @@ 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 +390,10 @@ 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 +403,10 @@ 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 +416,10 @@ 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> {
@@ -431,10 +431,10 @@ 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

@@ -6,9 +6,43 @@
 #include <boost/test/included/unit_test.hpp>
 #endif
 #include <toml.hpp>
+#include <deque>
+#include <map>
 #include <iostream>
 #include <fstream>
 
+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)
 {
@@ -20,15 +54,146 @@ BOOST_AUTO_TEST_CASE(test_example)
 
     auto serialized = toml::parse("tmp1.toml");
     {
-        auto& owner = toml::get<toml::table>(serialized.at("owner"));
-        auto& bio   = toml::get<std::string>(owner.at("bio"));
+        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_CHECK(data == serialized);
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_example_map_dq)
+{
+    const auto data = toml::parse<toml::discard_comments, std::map, std::deque>(
+            "toml/tests/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>("toml/tests/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>("toml/tests/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/tests/example.toml");
+        auto serialized = toml::parse("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>(
+            "toml/tests/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>("toml/tests/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/tests/example.toml");
+        auto serialized = toml::parse("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)
@@ -39,7 +204,43 @@ BOOST_AUTO_TEST_CASE(test_fruit)
         ofs << std::setw(80) << data;
     }
     const auto serialized = toml::parse("tmp2.toml");
-    BOOST_CHECK(data == serialized);
+    BOOST_TEST(data == serialized);
+}
+
+BOOST_AUTO_TEST_CASE(test_fruit_map_dq)
+{
+    const auto data = toml::parse<toml::discard_comments, std::map, std::deque>(
+            "toml/tests/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>("toml/tests/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>(
+        "toml/tests/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)
@@ -50,5 +251,55 @@ BOOST_AUTO_TEST_CASE(test_hard_example)
         ofs << std::setw(80) << data;
     }
     const auto serialized = toml::parse("tmp3.toml");
-    BOOST_CHECK(data == serialized);
+    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>(
+            "toml/tests/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>(
+            "toml/tests/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));
+    }
 }

tests/test_string.cpp

@@ -0,0 +1,113 @@
+#define BOOST_TEST_MODULE "test_string"
+#include <boost/test/unit_test.hpp>
+#include <toml.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());
+    }
+}
+

tests/test_traits.cpp

@@ -37,48 +37,48 @@ 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

@@ -14,69 +14,39 @@ BOOST_AUTO_TEST_CASE(test_resize)
     {
         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);
+        BOOST_TEST(toml::detail::has_resize_method<resizable_type>::value);
+        BOOST_TEST(!toml::detail::has_resize_method<non_resizable_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);
+        toml::resize(v, 10);
+        BOOST_TEST(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);
+        toml::resize(a, 10);
+        BOOST_TEST(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);
+        BOOST_CHECK_THROW(toml::resize(a, 20), std::invalid_argument);
     }
 }
 
 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);
     }
 }

toml.hpp

@@ -36,7 +36,6 @@
 #include "toml/parser.hpp"
 #include "toml/literal.hpp"
 #include "toml/serializer.hpp"
-#include "toml/from_toml.hpp"
 #include "toml/get.hpp"
 
 #endif// TOML_FOR_MODERN_CPP

toml/combinator.hpp

@@ -45,7 +45,7 @@ inline std::string show_char(const char c)
         buf.fill('\0');
         const auto r = std::snprintf(
                 buf.data(), buf.size(), "0x%02x", static_cast<int>(c) & 0xFF);
-        assert(r == buf.size() - 1);
+        assert(r == static_cast<int>(buf.size()) - 1);
         return std::string(buf.data());
     }
 }
@@ -56,31 +56,24 @@ struct character
     static constexpr char target = C;
 
     template<typename Cont>
-    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& 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)
         {
-            if(msg)
-            {
-                return err(concat_to_string("expected '", show_char(target),
-                                            "' but got '", show_char(c), "'."));
-            }
-            return err("");
+            return none();
         }
         loc.advance(); // update location
 
         return ok(region<Cont>(loc, first, loc.iter()));
     }
-
-    static std::string pattern() {return show_char(target);}
 };
 template<char C>
 constexpr char character<C>::target;
@@ -96,35 +89,24 @@ struct in_range
     static constexpr char lower = Low;
 
     template<typename Cont>
-    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& 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)
         {
-            if(msg)
-            {
-                return err(concat_to_string("expected character in range "
-                    "[", show_char(lower), ", ", show_char(upper), "] but got ",
-                    "'", show_char(c), "'."));
-            }
-            return err("");
+            return none();
         }
 
         loc.advance();
         return ok(region<Cont>(loc, first, loc.iter()));
     }
-
-    static std::string pattern()
-    {
-        return concat_to_string("[",show_char(lower),"-",show_char(upper),"]");
-    }
 };
 template<char L, char U> constexpr char in_range<L, U>::upper;
 template<char L, char U> constexpr char in_range<L, U>::lower;
@@ -135,34 +117,24 @@ template<typename Combinator>
 struct exclude
 {
     template<typename Cont>
-    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& 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, msg);
+        auto rslt = Combinator::invoke(loc);
         if(rslt.is_ok())
         {
             loc.reset(first);
-            if(msg)
-            {
-                return err(concat_to_string("invalid pattern (",
-                    Combinator::pattern(), ") appeared ", rslt.unwrap().str()));
-            }
-            return err("");
+            return none();
         }
         loc.reset(std::next(first)); // XXX maybe loc.advance() is okay but...
         return ok(region<Cont>(loc, first, loc.iter()));
     }
-
-    static std::string pattern()
-    {
-        return concat_to_string("^(", Combinator::pattern(), ')');
-    }
 };
 
 // increment `iter`, if matches. otherwise, just return empty string.
@@ -170,24 +142,19 @@ template<typename Combinator>
 struct maybe
 {
     template<typename Cont>
-    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& 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, msg);
+        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(), ")?");
-    }
 };
 
 template<typename ... Ts>
@@ -197,41 +164,35 @@ template<typename Head, typename ... Tail>
 struct sequence<Head, Tail...>
 {
     template<typename Cont>
-    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& 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, msg);
+        const auto rslt = Head::invoke(loc);
         if(rslt.is_err())
         {
             loc.reset(first);
-            return err(rslt.unwrap_err());
+            return none();
         }
-        return sequence<Tail...>::invoke(loc, std::move(rslt.unwrap()), first, msg);
+        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,
-           const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& loc, region<Cont> reg, Iterator first)
     {
-        const auto rslt = Head::invoke(loc, msg);
+        const auto rslt = Head::invoke(loc);
         if(rslt.is_err())
         {
             loc.reset(first);
-            return err(rslt.unwrap_err());
+            return none();
         }
         reg += rslt.unwrap(); // concat regions
-        return sequence<Tail...>::invoke(loc, std::move(reg), first, msg);
-    }
-
-    static std::string pattern()
-    {
-        return concat_to_string(Head::pattern(), sequence<Tail...>::pattern());
+        return sequence<Tail...>::invoke(loc, std::move(reg), first);
     }
 };
 
@@ -240,20 +201,18 @@ 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,
-           const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& loc, region<Cont> reg, Iterator first)
     {
-        const auto rslt = Head::invoke(loc, msg);
+        const auto rslt = Head::invoke(loc);
         if(rslt.is_err())
         {
             loc.reset(first);
-            return err(rslt.unwrap_err());
+            return none();
         }
         reg += rslt.unwrap(); // concat regions
         return ok(reg);
     }
-    static std::string pattern() {return Head::pattern();}
 };
 
 template<typename ... Ts>
@@ -263,36 +222,27 @@ template<typename Head, typename ... Tail>
 struct either<Head, Tail...>
 {
     template<typename Cont>
-    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& 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, msg);
+        const auto rslt = Head::invoke(loc);
         if(rslt.is_ok()) {return rslt;}
-        return either<Tail...>::invoke(loc, msg);
-    }
-
-    static std::string pattern()
-    {
-        return concat_to_string('(', Head::pattern(), ")|", either<Tail...>::pattern());
+        return either<Tail...>::invoke(loc);
     }
 };
 template<typename Head>
 struct either<Head>
 {
     template<typename Cont>
-    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& loc)
     {
         static_assert(std::is_same<char, typename Cont::value_type>::value,
                       "internal error: container::value_type should be `char`.");
-        return Head::invoke(loc, msg);
-    }
-    static std::string pattern()
-    {
-        return concat_to_string('(', Head::pattern(), ')');
+        return Head::invoke(loc);
     }
 };
 
@@ -307,52 +257,48 @@ 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, const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& loc)
     {
         region<Cont> retval(loc);
         const auto first = loc.iter();
         for(std::size_t i=0; i<N; ++i)
         {
-            auto rslt = T::invoke(loc, msg);
+            auto rslt = T::invoke(loc);
             if(rslt.is_err())
             {
                 loc.reset(first);
-                return err(rslt.unwrap_err());
+                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, const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& loc)
     {
         region<Cont> retval(loc);
 
         const auto first = loc.iter();
         for(std::size_t i=0; i<N; ++i)
         {
-            auto rslt = T::invoke(loc, msg);
+            auto rslt = T::invoke(loc);
             if(rslt.is_err())
             {
                 loc.reset(first);
-                return err(rslt.unwrap_err());
+                return none();
             }
             retval += rslt.unwrap();
         }
         while(true)
         {
-            auto rslt = T::invoke(loc, msg);
+            auto rslt = T::invoke(loc);
             if(rslt.is_err())
             {
                 return ok(std::move(retval));
@@ -360,23 +306,19 @@ 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, const bool msg = false)
+    static result<region<Cont>, none_t>
+    invoke(location<Cont>& loc)
     {
         region<Cont> retval(loc);
         while(true)
         {
-            auto rslt = T::invoke(loc, msg);
+            auto rslt = T::invoke(loc);
             if(rslt.is_err())
             {
                 return ok(std::move(retval));
@@ -384,7 +326,6 @@ struct repeat<T, unlimited>
             retval += rslt.unwrap();
         }
     }
-    static std::string pattern() {return concat_to_string('(', T::pattern(), ")*");}
 };
 
 } // detail

toml/comments.hpp

@@ -0,0 +1,416 @@
+//     Copyright Toru Niina 2019.
+// Distributed under the MIT License.
+#ifndef TOML11_COMMENTS_HPP
+#define TOML11_COMMENTS_HPP
+#include <type_traits>
+#include <utility>
+#include <iterator>
+#include <initializer_list>
+#include <vector>
+#include <string>
+
+// 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);}
+
+    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);
+    }
+
+    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 choosed 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 {return *data();}
+    const_reference operator[](const size_type) const noexcept {return *data();}
+    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 {return *data();}
+    const_reference front() const noexcept {return *data();}
+    reference       back()        noexcept {return *data();}
+    const_reference back()  const noexcept {return *data();}
+
+    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{};}
+};
+
+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

@@ -46,7 +46,7 @@ inline std::tm localtime_s(const std::time_t* src)
 #endif
 } // detail
 
-enum class month_t : std::int8_t
+enum class month_t : std::uint8_t
 {
     Jan =  0,
     Feb =  1,
@@ -98,9 +98,9 @@ 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;
@@ -188,22 +188,22 @@ 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
@@ -353,15 +353,15 @@ 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);
-        std::tm time = detail::localtime_s(&t);
+        std::tm ltime = detail::localtime_s(&t);
 
-        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));
+            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>(

toml/from_toml.hpp

@@ -1,71 +0,0 @@
-//     Copyright Toru Niina 2017.
-// Distributed under the MIT License.
-#ifndef TOML11_FROM_TOML_HPP
-#define TOML11_FROM_TOML_HPP
-#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& ...>, const toml::value&)
-    {
-        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/literal.hpp

@@ -11,7 +11,7 @@ inline namespace literals
 inline namespace toml_literals
 {
 
-inline ::toml::value operator""_toml(const char* str, std::size_t len)
+inline ::toml::value operator"" _toml(const char* str, std::size_t len)
 {
     ::toml::detail::location<std::vector<char>>
         loc(/* filename = */ std::string("TOML literal encoded in a C++ code"),
@@ -53,7 +53,7 @@ inline ::toml::value operator""_toml(const char* str, std::size_t len)
     // 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(loc))
+        if(auto data = ::toml::detail::parse_value<::toml::value>(loc))
         {
             return data.unwrap();
         }
@@ -70,14 +70,9 @@ inline ::toml::value operator""_toml(const char* str, std::size_t len)
     // 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(loc))
+    if(auto data = ::toml::detail::parse_toml_file<::toml::value>(loc))
     {
-        loc.reset(loc.begin()); // rollback to the top of the literal
-        // skip needless characters for error message
-        skip_line::invoke(loc); // skip the first several needless lines
-        skip_ws::invoke(loc);   // skip the first several needless whitespaces
-        return ::toml::value(std::move(data.unwrap()),
-                ::toml::detail::region<std::vector<char>>(std::move(loc)));
+        return data.unwrap();
     }
     else // none of them.
     {

toml/parser.hpp

@@ -253,6 +253,11 @@ std::string read_utf8_codepoint(const region<Container>& reg,
     std::istringstream iss(str);
     iss >> std::hex >> codepoint;
 
+    const auto to_char = [](const int i) noexcept -> char {
+        const auto uc = static_cast<unsigned char>(i);
+        return *reinterpret_cast<const char*>(std::addressof(uc));
+    };
+
     std::string character;
     if(codepoint < 0x80) // U+0000 ... U+0079 ; just an ASCII.
     {
@@ -261,8 +266,8 @@ std::string read_utf8_codepoint(const region<Container>& reg,
     else if(codepoint < 0x800) //U+0080 ... U+07FF
     {
         // 110yyyyx 10xxxxxx; 0x3f == 0b0011'1111
-        character += static_cast<unsigned char>(0xC0| codepoint >> 6);
-        character += static_cast<unsigned char>(0x80|(codepoint & 0x3F));
+        character += to_char(0xC0| codepoint >> 6);
+        character += to_char(0x80|(codepoint & 0x3F));
     }
     else if(codepoint < 0x10000) // U+0800...U+FFFF
     {
@@ -276,17 +281,17 @@ std::string read_utf8_codepoint(const region<Container>& reg,
         }
         assert(codepoint < 0xD800 || 0xDFFF < codepoint);
         // 1110yyyy 10yxxxxx 10xxxxxx
-        character += static_cast<unsigned char>(0xE0| codepoint >> 12);
-        character += static_cast<unsigned char>(0x80|(codepoint >> 6 & 0x3F));
-        character += static_cast<unsigned char>(0x80|(codepoint      & 0x3F));
+        character += to_char(0xE0| codepoint >> 12);
+        character += to_char(0x80|(codepoint >> 6 & 0x3F));
+        character += to_char(0x80|(codepoint      & 0x3F));
     }
     else if(codepoint < 0x110000) // U+010000 ... U+10FFFF
     {
         // 11110yyy 10yyxxxx 10xxxxxx 10xxxxxx
-        character += static_cast<unsigned char>(0xF0| codepoint >> 18);
-        character += static_cast<unsigned char>(0x80|(codepoint >> 12 & 0x3F));
-        character += static_cast<unsigned char>(0x80|(codepoint >> 6  & 0x3F));
-        character += static_cast<unsigned char>(0x80|(codepoint       & 0x3F));
+        character += to_char(0xF0| codepoint >> 18);
+        character += to_char(0x80|(codepoint >> 12 & 0x3F));
+        character += to_char(0x80|(codepoint >> 6  & 0x3F));
+        character += to_char(0x80|(codepoint       & 0x3F));
     }
     else // out of UTF-8 region
     {
@@ -376,7 +381,7 @@ parse_ml_basic_string(location<Container>& loc)
         // immediate newline is ignored (if exists)
         /* discard return value */ lex_newline::invoke(inner_loc);
 
-        delim = err("tmp");
+        delim = none();
         while(!delim)
         {
             using lex_unescaped_seq = repeat<
@@ -432,7 +437,7 @@ parse_basic_string(location<Container>& loc)
         std::string retval;
         retval.reserve(token.unwrap().size());
 
-        quot = err("tmp");
+        quot = none();
         while(!quot)
         {
             using lex_unescaped_seq = repeat<lex_basic_unescaped, unlimited>;
@@ -587,23 +592,17 @@ parse_local_date(location<Container>& loc)
         const auto y = lex_date_fullyear::invoke(inner_loc);
         if(!y || inner_loc.iter() == inner_loc.end() || *inner_loc.iter() != '-')
         {
-            const std::string msg = y.map_err_or_else(
-                [](const std::string& msg) {return msg;}, "should be `-`");
-
             throw internal_error(format_underline("[error]: "
                 "toml::parse_inner_local_date: invalid year format",
-                {{std::addressof(inner_loc), msg}}));
+                {{std::addressof(inner_loc), "should be `-`"}}));
         }
         inner_loc.advance();
         const auto m = lex_date_month::invoke(inner_loc);
         if(!m || inner_loc.iter() == inner_loc.end() || *inner_loc.iter() != '-')
         {
-            const std::string msg = m.map_err_or_else(
-                [](const std::string& msg) {return msg;}, "should be `-`");
-
             throw internal_error(format_underline("[error]: "
                 "toml::parse_local_date: invalid month format",
-                {{std::addressof(inner_loc), msg}}));
+                {{std::addressof(inner_loc), "should be `-`"}}));
         }
         inner_loc.advance();
         const auto d = lex_date_mday::invoke(inner_loc);
@@ -611,7 +610,7 @@ parse_local_date(location<Container>& loc)
         {
             throw internal_error(format_underline("[error]: "
                 "toml::parse_local_date: invalid day format",
-                {{std::addressof(inner_loc), d.unwrap_err()}}));
+                {{std::addressof(inner_loc), "here"}}));
         }
         return ok(std::make_pair(local_date(
             static_cast<std::int16_t>(from_string<int>(y.unwrap().str(), 0)),
@@ -640,23 +639,17 @@ parse_local_time(location<Container>& loc)
         const auto h = lex_time_hour::invoke(inner_loc);
         if(!h || inner_loc.iter() == inner_loc.end() || *inner_loc.iter() != ':')
         {
-            const std::string msg = h.map_err_or_else(
-                [](const std::string& msg) {return msg;}, "should be `:`");
-
             throw internal_error(format_underline("[error]: "
                 "toml::parse_local_time: invalid year format",
-                {{std::addressof(inner_loc), msg}}));
+                {{std::addressof(inner_loc), "should be `:`"}}));
         }
         inner_loc.advance();
         const auto m = lex_time_minute::invoke(inner_loc);
         if(!m || inner_loc.iter() == inner_loc.end() || *inner_loc.iter() != ':')
         {
-            const std::string msg = m.map_err_or_else(
-                [](const std::string& msg) {return msg;}, "should be `:`");
-
             throw internal_error(format_underline("[error]: "
                 "toml::parse_local_time: invalid month format",
-                {{std::addressof(inner_loc), msg}}));
+                {{std::addressof(inner_loc), "should be `:`"}}));
         }
         inner_loc.advance();
         const auto s = lex_time_second::invoke(inner_loc);
@@ -664,12 +657,12 @@ parse_local_time(location<Container>& loc)
         {
             throw internal_error(format_underline("[error]: "
                 "toml::parse_local_time: invalid second format",
-                {{std::addressof(inner_loc), s.unwrap_err()}}));
+                {{std::addressof(inner_loc), "here"}}));
         }
         local_time time(
-            static_cast<std::int8_t>(from_string<int>(h.unwrap().str(), 0)),
-            static_cast<std::int8_t>(from_string<int>(m.unwrap().str(), 0)),
-            static_cast<std::int8_t>(from_string<int>(s.unwrap().str(), 0)), 0, 0);
+            from_string<int>(h.unwrap().str(), 0),
+            from_string<int>(m.unwrap().str(), 0),
+            from_string<int>(s.unwrap().str(), 0), 0, 0);
 
         const auto before_secfrac = inner_loc.iter();
         if(const auto secfrac = lex_time_secfrac::invoke(inner_loc))
@@ -685,13 +678,13 @@ parse_local_time(location<Container>& loc)
             }
             if(sf.size() >= 6)
             {
-                time.millisecond = from_string<std::int16_t>(sf.substr(0, 3), 0);
-                time.microsecond = from_string<std::int16_t>(sf.substr(3, 3), 0);
+                time.millisecond = from_string<std::uint16_t>(sf.substr(0, 3), 0u);
+                time.microsecond = from_string<std::uint16_t>(sf.substr(3, 3), 0u);
             }
             else if(sf.size() >= 3)
             {
-                time.millisecond = from_string<std::int16_t>(sf, 0);
-                time.microsecond = 0;
+                time.millisecond = from_string<std::uint16_t>(sf, 0u);
+                time.microsecond = 0u;
             }
         }
         else
@@ -700,7 +693,7 @@ parse_local_time(location<Container>& loc)
             {
                 throw internal_error(format_underline("[error]: "
                     "toml::parse_local_time: invalid subsecond format",
-                    {{std::addressof(inner_loc), secfrac.unwrap_err()}}));
+                    {{std::addressof(inner_loc), "here"}}));
             }
         }
         return ok(std::make_pair(time, token.unwrap()));
@@ -724,12 +717,9 @@ parse_local_datetime(location<Container>& loc)
         const auto date = parse_local_date(inner_loc);
         if(!date || inner_loc.iter() == inner_loc.end())
         {
-            const std::string msg = date.map_err_or_else(
-                [](const std::string& msg) {return msg;}, "date, not datetime");
-
             throw internal_error(format_underline("[error]: "
                 "toml::parse_local_datetime: invalid datetime format",
-                {{std::addressof(inner_loc), msg}}));
+                {{std::addressof(inner_loc), "date, not datetime"}}));
         }
         const char delim = *(inner_loc.iter());
         if(delim != 'T' && delim != 't' && delim != ' ')
@@ -769,12 +759,9 @@ parse_offset_datetime(location<Container>& loc)
         const auto datetime = parse_local_datetime(inner_loc);
         if(!datetime || inner_loc.iter() == inner_loc.end())
         {
-            const std::string msg = datetime.map_err_or_else(
-                [](const std::string& msg){return msg;}, "date, not datetime");
-
             throw internal_error(format_underline("[error]: "
                 "toml::parse_offset_datetime: invalid datetime format",
-                {{std::addressof(inner_loc), msg}}));
+                {{std::addressof(inner_loc), "date, not datetime"}}));
         }
         time_offset offset(0, 0);
         if(const auto ofs = lex_time_numoffset::invoke(inner_loc))
@@ -887,13 +874,16 @@ parse_key(location<Container>& loc)
 }
 
 // forward-decl to implement parse_array and parse_table
-template<typename Container>
-result<value, std::string> parse_value(location<Container>&);
+template<typename Value, typename Container>
+result<Value, std::string> parse_value(location<Container>&);
 
-template<typename Container>
-result<std::pair<array, region<Container>>, std::string>
+template<typename Value, typename Container>
+result<std::pair<typename Value::array_type, region<Container>>, std::string>
 parse_array(location<Container>& loc)
 {
+    using value_type = Value;
+    using array_type = typename value_type::array_type;
+
     const auto first = loc.iter();
     if(loc.iter() == loc.end())
     {
@@ -908,7 +898,7 @@ parse_array(location<Container>& loc)
     using lex_ws_comment_newline = repeat<
         either<lex_wschar, lex_newline, lex_comment>, unlimited>;
 
-    array retval;
+    array_type retval;
     while(loc.iter() != loc.end())
     {
         lex_ws_comment_newline::invoke(loc); // skip
@@ -920,7 +910,7 @@ parse_array(location<Container>& loc)
                       region<Container>(loc, first, loc.iter())));
         }
 
-        if(auto val = parse_value(loc))
+        if(auto val = parse_value<value_type>(loc))
         {
             if(!retval.empty() && retval.front().type() != val.as_ok().type())
             {
@@ -984,10 +974,12 @@ parse_array(location<Container>& loc)
             {{std::addressof(loc), "should be closed"}}));
 }
 
-template<typename Container>
-result<std::pair<std::pair<std::vector<key>, region<Container>>, value>, std::string>
+template<typename Value, typename Container>
+result<std::pair<std::pair<std::vector<key>, region<Container>>, Value>, std::string>
 parse_key_value_pair(location<Container>& loc)
 {
+    using value_type = Value;
+
     const auto first = loc.iter();
     auto key_reg = parse_key(loc);
     if(!key_reg)
@@ -1031,7 +1023,7 @@ parse_key_value_pair(location<Container>& loc)
     }
 
     const auto after_kvsp = loc.iter(); // err msg
-    auto val = parse_value(loc);
+    auto val = parse_value<value_type>(loc);
     if(!val)
     {
         std::string msg;
@@ -1099,8 +1091,8 @@ parse_table_key(location<Container>& loc);
 // Here, it parses region of `tab->at(k)` as a table key and check the depth
 // of the key. If the key region points deeper node, it would be allowed.
 // Otherwise, the key points the same node. It would be rejected.
-template<typename Iterator>
-bool is_valid_forward_table_definition(const value& fwd,
+template<typename Value, typename Iterator>
+bool is_valid_forward_table_definition(const Value& fwd,
         Iterator key_first, Iterator key_curr, Iterator key_last)
 {
     location<std::string> def("internal", detail::get_region(fwd).str());
@@ -1141,9 +1133,9 @@ bool is_valid_forward_table_definition(const value& fwd,
     return false;
 }
 
-template<typename InputIterator, typename Container>
+template<typename Value, typename InputIterator, typename Container>
 result<bool, std::string>
-insert_nested_key(table& root, const toml::value& v,
+insert_nested_key(typename Value::table_type& root, const Value& v,
                   InputIterator iter, const InputIterator last,
                   region<Container> key_reg,
                   const bool is_array_of_table = false)
@@ -1151,10 +1143,14 @@ insert_nested_key(table& root, const toml::value& v,
     static_assert(std::is_same<key,
         typename std::iterator_traits<InputIterator>::value_type>::value,"");
 
+    using value_type = Value;
+    using table_type = typename value_type::table_type;
+    using array_type = typename value_type::array_type;
+
     const auto first = iter;
     assert(iter != last);
 
-    table* tab = std::addressof(root);
+    table_type* tab = std::addressof(root);
     for(; iter != last; ++iter) // search recursively
     {
         const key& k = *iter;
@@ -1167,7 +1163,7 @@ insert_nested_key(table& root, const toml::value& v,
             {
                 if(tab->count(k) == 1) // there is already an array of table
                 {
-                    if(tab->at(k).is(value_t::Table))
+                    if(tab->at(k).is_table())
                     {
                         // show special err msg for conflicting table
                         throw syntax_error(format_underline(concat_to_string(
@@ -1180,7 +1176,7 @@ insert_nested_key(table& root, const toml::value& v,
                                  "this conflicts with the previous table"}
                             }));
                     }
-                    else if(!(tab->at(k).is(value_t::Array)))
+                    else if(!(tab->at(k).is_array()))
                     {
                         throw syntax_error(format_underline(concat_to_string(
                             "[error] toml::insert_value: array of table (\"",
@@ -1193,8 +1189,9 @@ insert_nested_key(table& root, const toml::value& v,
                                  "while inserting this array-of-tables"}
                             }));
                     }
-                    array& a = tab->at(k).template cast<toml::value_t::Array>();
-                    if(!(a.front().is(value_t::Table)))
+                    // the above if-else-if checks tab->at(k) is an array
+                    auto& a = tab->at(k).as_array();
+                    if(!(a.front().is_table()))
                     {
                         throw syntax_error(format_underline(concat_to_string(
                             "[error] toml::insert_value: array of table (\"",
@@ -1240,7 +1237,7 @@ insert_nested_key(table& root, const toml::value& v,
                 }
                 else // if not, we need to create the array of table
                 {
-                    toml::value aot(toml::array(1, v), key_reg);
+                    value_type aot(array_type(1, v), key_reg);
                     tab->insert(std::make_pair(k, aot));
                     return ok(true);
                 }
@@ -1248,7 +1245,7 @@ insert_nested_key(table& root, const toml::value& v,
 
             if(tab->count(k) == 1)
             {
-                if(tab->at(k).is(value_t::Table) && v.is(value_t::Table))
+                if(tab->at(k).is_table() && v.is_table())
                 {
                     if(!is_valid_forward_table_definition(
                                 tab->at(k), first, iter, last))
@@ -1268,18 +1265,18 @@ insert_nested_key(table& root, const toml::value& v,
                     // d = 42
                     // [a]
                     // e = 2.71
-                    auto& t = tab->at(k).cast<value_t::Table>();
-                    for(const auto& kv : v.cast<value_t::Table>())
+                    auto& t = tab->at(k).as_table();
+                    for(const auto& kv : v.as_table())
                     {
                         t[kv.first] = kv.second;
                     }
                     detail::change_region(tab->at(k), key_reg);
                     return ok(true);
                 }
-                else if(v.is(value_t::Table)                          &&
-                        tab->at(k).is(value_t::Array)                 &&
-                        tab->at(k).cast<value_t::Array>().size() > 0  &&
-                        tab->at(k).cast<value_t::Array>().front().is(value_t::Table))
+                else if(v.is_table()                     &&
+                        tab->at(k).is_array()            &&
+                        tab->at(k).as_array().size() > 0 &&
+                        tab->at(k).as_array().front().is_table())
                 {
                     throw syntax_error(format_underline(concat_to_string(
                         "[error] toml::insert_value: array of tables (\"",
@@ -1315,18 +1312,18 @@ insert_nested_key(table& root, const toml::value& v,
             // [x.y.z]
             if(tab->count(k) == 0)
             {
-                (*tab)[k] = toml::value(toml::table{}, key_reg);
+                (*tab)[k] = value_type(table_type{}, key_reg);
             }
 
             // type checking...
-            if(tab->at(k).is(value_t::Table))
+            if(tab->at(k).is_table())
             {
-                tab = std::addressof((*tab)[k].template cast<value_t::Table>());
+                tab = std::addressof((*tab)[k].as_table());
             }
-            else if(tab->at(k).is(value_t::Array)) // inserting to array-of-tables?
+            else if(tab->at(k).is_array()) // inserting to array-of-tables?
             {
-                array& a = (*tab)[k].template cast<value_t::Array>();
-                if(!a.back().is(value_t::Table))
+                auto& a = (*tab)[k].as_array();
+                if(!a.back().is_table())
                 {
                     throw syntax_error(format_underline(concat_to_string(
                         "[error] toml::insert_value: target (",
@@ -1337,7 +1334,7 @@ insert_nested_key(table& root, const toml::value& v,
                             {std::addressof(get_region(v)), "inserting this"}
                         }));
                 }
-                tab = std::addressof(a.back().template cast<value_t::Table>());
+                tab = std::addressof(a.back().as_table());
             }
             else
             {
@@ -1355,15 +1352,18 @@ insert_nested_key(table& root, const toml::value& v,
     return err(std::string("toml::detail::insert_nested_key: never reach here"));
 }
 
-template<typename Container>
-result<std::pair<table, region<Container>>, std::string>
+template<typename Value, typename Container>
+result<std::pair<typename Value::table_type, region<Container>>, std::string>
 parse_inline_table(location<Container>& loc)
 {
+    using value_type = Value;
+    using table_type = typename value_type::table_type;
+
     const auto first = loc.iter();
-    table retval;
+    table_type retval;
     if(!(loc.iter() != loc.end() && *loc.iter() == '{'))
     {
-        return err(format_underline("[error] toml::parse_inline_table: ", 
+        return err(format_underline("[error] toml::parse_inline_table: ",
             {{std::addressof(loc), "the next token is not an inline table"}}));
     }
     loc.advance();
@@ -1378,14 +1378,14 @@ parse_inline_table(location<Container>& loc)
                         retval, region<Container>(loc, first, loc.iter())));
         }
 
-        const auto kv_r = parse_key_value_pair(loc);
+        const auto kv_r = parse_key_value_pair<value_type>(loc);
         if(!kv_r)
         {
             return err(kv_r.unwrap_err());
         }
         const std::vector<key>&  keys    = kv_r.unwrap().first.first;
         const region<Container>& key_reg = kv_r.unwrap().first.second;
-        const value&             val     = kv_r.unwrap().second;
+        const value_type&        val     = kv_r.unwrap().second;
 
         const auto inserted =
             insert_nested_key(retval, val, keys.begin(), keys.end(), key_reg);
@@ -1427,48 +1427,165 @@ parse_inline_table(location<Container>& loc)
 }
 
 template<typename Container>
-value_t guess_number_type(const location<Container>& l)
+result<value_t, std::string> guess_number_type(const location<Container>& l)
 {
+    // This function tries to find some (common) mistakes by checking characters
+    // that follows the last character of a value. But it is often difficult
+    // because some non-newline characters can appear after a value. E.g.
+    // spaces, tabs, commas (in an array or inline table), closing brackets
+    // (of an array or inline table), comment-sign (#). Since this function
+    // does not parse further, those characters are always allowed to be there.
     location<Container> loc = l;
 
-    if(lex_offset_date_time::invoke(loc)) {return value_t::OffsetDatetime;}
+    if(lex_offset_date_time::invoke(loc)) {return ok(value_t::offset_datetime);}
     loc.reset(l.iter());
 
-    if(lex_local_date_time::invoke(loc)) {return value_t::LocalDatetime;}
+    if(lex_local_date_time::invoke(loc))
+    {
+        // bad offset may appear after this.
+        if(loc.iter() != loc.end() && (*loc.iter() == '+' || *loc.iter() == '-'
+                    || *loc.iter() == 'Z' || *loc.iter() == 'z'))
+        {
+            return err(format_underline("[error] bad offset: should be [+-]HH:MM or Z",
+                        {{std::addressof(loc), "[+-]HH:MM or Z"}},
+                        {"pass: +09:00, -05:30", "fail: +9:00, -5:30"}));
+        }
+        return ok(value_t::local_datetime);
+    }
     loc.reset(l.iter());
 
-    if(lex_local_date::invoke(loc)) {return value_t::LocalDate;}
+    if(lex_local_date::invoke(loc))
+    {
+        // bad time may appear after this.
+        // A space is allowed as a delimiter between local time. But there are
+        // both cases in which a space becomes valid or invalid.
+        // - invalid: 2019-06-16 7:00:00
+        // - valid  : 2019-06-16 07:00:00
+        if(loc.iter() != loc.end())
+        {
+            const auto c = *loc.iter();
+            if(c == 'T' || c == 't')
+            {
+                return err(format_underline("[error] bad time: should be HH:MM:SS.subsec",
+                        {{std::addressof(loc), "HH:MM:SS.subsec"}},
+                        {"pass: 1979-05-27T07:32:00, 1979-05-27 07:32:00.999999",
+                         "fail: 1979-05-27T7:32:00, 1979-05-27 17:32"}));
+            }
+            if('0' <= c && c <= '9')
+            {
+                return err(format_underline("[error] bad time: missing T",
+                        {{std::addressof(loc), "T or space required here"}},
+                        {"pass: 1979-05-27T07:32:00, 1979-05-27 07:32:00.999999",
+                         "fail: 1979-05-27T7:32:00, 1979-05-27 7:32"}));
+            }
+            if(c == ' ' && std::next(loc.iter()) != loc.end() &&
+                ('0' <= *std::next(loc.iter()) && *std::next(loc.iter())<= '9'))
+            {
+                loc.advance();
+                return err(format_underline("[error] bad time: should be HH:MM:SS.subsec",
+                        {{std::addressof(loc), "HH:MM:SS.subsec"}},
+                        {"pass: 1979-05-27T07:32:00, 1979-05-27 07:32:00.999999",
+                         "fail: 1979-05-27T7:32:00, 1979-05-27 7:32"}));
+            }
+        }
+        return ok(value_t::local_date);
+    }
     loc.reset(l.iter());
 
-    if(lex_local_time::invoke(loc)) {return value_t::LocalTime;}
+    if(lex_local_time::invoke(loc)) {return ok(value_t::local_time);}
     loc.reset(l.iter());
 
-    if(lex_float::invoke(loc)) {return value_t::Float;}
+    if(lex_float::invoke(loc))
+    {
+        if(loc.iter() != loc.end() && *loc.iter() == '_')
+        {
+            return err(format_underline("[error] bad float: `_` should be surrounded by digits",
+                        {{std::addressof(loc), "here"}},
+                        {"pass: +1.0, -2e-2, 3.141_592_653_589, inf, nan",
+                         "fail: .0, 1., _1.0, 1.0_, 1_.0, 1.0__0"}));
+        }
+        return ok(value_t::floating);
+    }
     loc.reset(l.iter());
 
-    return value_t::Integer;
+    if(lex_integer::invoke(loc))
+    {
+        if(loc.iter() != loc.end())
+        {
+            const auto c = *loc.iter();
+            if(c == '_')
+            {
+                return err(format_underline("[error] bad integer: `_` should be surrounded by digits",
+                            {{std::addressof(loc), "here"}},
+                            {"pass: -42, 1_000, 1_2_3_4_5, 0xC0FFEE, 0b0010, 0o755",
+                             "fail: 1__000, 0123"}));
+            }
+            if('0' <= c && c <= '9')
+            {
+                // leading zero. point '0'
+                loc.retrace();
+                return err(format_underline("[error] bad integer: leading zero",
+                            {{std::addressof(loc), "here"}},
+                            {"pass: -42, 1_000, 1_2_3_4_5, 0xC0FFEE, 0b0010, 0o755",
+                             "fail: 1__000, 0123"}));
+            }
+            if(c == ':' || c == '-')
+            {
+                return err(format_underline("[error] bad datetime: invalid format",
+                            {{std::addressof(loc), "here"}},
+                            {"pass: 1979-05-27T07:32:00-07:00, 1979-05-27 07:32:00.999999Z",
+                             "fail: 1979-05-27T7:32:00-7:00, 1979-05-27 7:32-00:30"}));
+            }
+            if(c == '.' || c == 'e' || c == 'E')
+            {
+                return err(format_underline("[error] bad float: invalid format",
+                            {{std::addressof(loc), "here"}},
+                            {"pass: +1.0, -2e-2, 3.141_592_653_589, inf, nan",
+                             "fail: .0, 1., _1.0, 1.0_, 1_.0, 1.0__0"}));
+            }
+        }
+        return ok(value_t::integer);
+    }
+    if(loc.iter() != loc.end() && *loc.iter() == '.')
+    {
+        return err(format_underline("[error] bad float: invalid format",
+                {{std::addressof(loc), "integer part required before this"}},
+                {"pass: +1.0, -2e-2, 3.141_592_653_589, inf, nan",
+                 "fail: .0, 1., _1.0, 1.0_, 1_.0, 1.0__0"}));
+    }
+    if(loc.iter() != loc.end() && *loc.iter() == '_')
+    {
+        return err(format_underline("[error] bad number: `_` should be surrounded by digits",
+                {{std::addressof(loc), "`_` is not surrounded by digits"}},
+                {"pass: -42, 1_000, 1_2_3_4_5, 0xC0FFEE, 0b0010, 0o755",
+                 "fail: 1__000, 0123"}));
+    }
+    return err(format_underline("[error] bad format: unknown value appeared",
+                {{std::addressof(loc), "here"}}));
 }
 
 template<typename Container>
-value_t guess_value_type(const location<Container>& loc)
+result<value_t, std::string> guess_value_type(const location<Container>& loc)
 {
     switch(*loc.iter())
     {
-        case '"' : {return value_t::String; }
-        case '\'': {return value_t::String; }
-        case 't' : {return value_t::Boolean;}
-        case 'f' : {return value_t::Boolean;}
-        case '[' : {return value_t::Array;  }
-        case '{' : {return value_t::Table;  }
-        case 'i' : {return value_t::Float;  } // inf.
-        case 'n' : {return value_t::Float;  } // nan.
+        case '"' : {return ok(value_t::string);  }
+        case '\'': {return ok(value_t::string);  }
+        case 't' : {return ok(value_t::boolean); }
+        case 'f' : {return ok(value_t::boolean); }
+        case '[' : {return ok(value_t::array);   }
+        case '{' : {return ok(value_t::table);   }
+        case 'i' : {return ok(value_t::floating);} // inf.
+        case 'n' : {return ok(value_t::floating);} // nan.
         default  : {return guess_number_type(loc);}
     }
 }
 
-template<typename Container>
-result<value, std::string> parse_value(location<Container>& loc)
+template<typename Value, typename Container>
+result<Value, std::string> parse_value(location<Container>& loc)
 {
+    using value_type = Value;
+
     const auto first = loc.iter();
     if(first == loc.end())
     {
@@ -1476,18 +1593,23 @@ result<value, std::string> parse_value(location<Container>& loc)
                    {{std::addressof(loc), ""}}));
     }
 
-    switch(guess_value_type(loc))
+    const auto type = guess_value_type(loc);
+    if(!type)
     {
-        case value_t::Boolean        : {return parse_boolean(loc);        }
-        case value_t::Integer        : {return parse_integer(loc);        }
-        case value_t::Float          : {return parse_floating(loc);       }
-        case value_t::String         : {return parse_string(loc);         }
-        case value_t::OffsetDatetime : {return parse_offset_datetime(loc);}
-        case value_t::LocalDatetime  : {return parse_local_datetime(loc); }
-        case value_t::LocalDate      : {return parse_local_date(loc);     }
-        case value_t::LocalTime      : {return parse_local_time(loc);     }
-        case value_t::Array          : {return parse_array(loc);          }
-        case value_t::Table          : {return parse_inline_table(loc);   }
+        return err(type.unwrap_err());
+    }
+    switch(type.unwrap())
+    {
+        case value_t::boolean        : {return parse_boolean(loc);        }
+        case value_t::integer        : {return parse_integer(loc);        }
+        case value_t::floating       : {return parse_floating(loc);       }
+        case value_t::string         : {return parse_string(loc);         }
+        case value_t::offset_datetime: {return parse_offset_datetime(loc);}
+        case value_t::local_datetime : {return parse_local_datetime(loc); }
+        case value_t::local_date     : {return parse_local_date(loc);     }
+        case value_t::local_time     : {return parse_local_time(loc);     }
+        case value_t::array          : {return parse_array<value_type>(loc);       }
+        case value_t::table          : {return parse_inline_table<value_type>(loc);}
         default:
         {
             const auto msg = format_underline("[error] toml::parse_value: "
@@ -1560,7 +1682,7 @@ template<typename Container>
 result<std::pair<std::vector<key>, region<Container>>, std::string>
 parse_array_table_key(location<Container>& loc)
 {
-    if(auto token = lex_array_table::invoke(loc, true))
+    if(auto token = lex_array_table::invoke(loc))
     {
         location<std::string> inner_loc(loc.name(), token.unwrap().str());
 
@@ -1611,13 +1733,17 @@ parse_array_table_key(location<Container>& loc)
 }
 
 // parse table body (key-value pairs until the iter hits the next [tablekey])
-template<typename Container>
-result<table, std::string> parse_ml_table(location<Container>& loc)
+template<typename Value, typename Container>
+result<typename Value::table_type, std::string>
+parse_ml_table(location<Container>& loc)
 {
+    using value_type = Value;
+    using table_type = typename value_type::table_type;
+
     const auto first = loc.iter();
     if(first == loc.end())
     {
-        return ok(toml::table{});
+        return ok(table_type{});
     }
 
     // XXX at lest one newline is needed.
@@ -1625,7 +1751,7 @@ result<table, std::string> parse_ml_table(location<Container>& loc)
         sequence<maybe<lex_ws>, maybe<lex_comment>, lex_newline>, at_least<1>>;
     skip_line::invoke(loc);
 
-    table tab;
+    table_type tab;
     while(loc.iter() != loc.end())
     {
         lex_ws::invoke(loc);
@@ -1641,11 +1767,11 @@ result<table, std::string> parse_ml_table(location<Container>& loc)
             return ok(tab);
         }
 
-        if(const auto kv = parse_key_value_pair(loc))
+        if(const auto kv = parse_key_value_pair<value_type>(loc))
         {
-            const std::vector<key>& keys     = kv.unwrap().first.first;
+            const std::vector<key>&  keys    = kv.unwrap().first.first;
             const region<Container>& key_reg = kv.unwrap().first.second;
-            const value&            val      = kv.unwrap().second;
+            const value_type&        val     = kv.unwrap().second;
             const auto inserted =
                 insert_nested_key(tab, val, keys.begin(), keys.end(), key_reg);
             if(!inserted)
@@ -1672,12 +1798,12 @@ result<table, std::string> parse_ml_table(location<Container>& loc)
         const auto newline = skip_line::invoke(loc);
         if(!newline && loc.iter() != loc.end())
         {
-            const auto before = loc.iter();
+            const auto before2 = loc.iter();
             lex_ws::invoke(loc); // skip whitespace
             const auto msg = format_underline("[error] toml::parse_table: "
                 "invalid line format", {{std::addressof(loc), concat_to_string(
                 "expected newline, but got '", show_char(*loc.iter()), "'.")}});
-            loc.reset(before);
+            loc.reset(before2);
             return err(msg);
         }
 
@@ -1690,18 +1816,59 @@ result<table, std::string> parse_ml_table(location<Container>& loc)
     return ok(tab);
 }
 
-template<typename Container>
-result<table, std::string> parse_toml_file(location<Container>& loc)
+template<typename Value, typename Container>
+result<Value, std::string> parse_toml_file(location<Container>& loc)
 {
+    using value_type = Value;
+    using table_type = typename value_type::table_type;
+
     const auto first = loc.iter();
     if(first == loc.end())
     {
-        return ok(toml::table{});
+        return ok(value_type(table_type{}));
     }
 
-    table data;
+    // put the first line as a region of a file
+    const region<Container> file(loc, loc.iter(),
+            std::find(loc.iter(), loc.end(), '\n'));
+
+    // The first successive comments that are separated from the first value
+    // by an empty line are for a file itself.
+    // ```toml
+    // # this is a comment for a file.
+    //
+    // key = "the first value"
+    // ```
+    // ```toml
+    // # this is a comment for "the first value".
+    // key = "the first value"
+    // ```
+    std::vector<std::string> comments;
+    using lex_first_comments = sequence<
+        repeat<sequence<maybe<lex_ws>, lex_comment, lex_newline>, at_least<1>>,
+        sequence<maybe<lex_ws>, lex_newline>
+        >;
+    if(const auto token = lex_first_comments::invoke(loc))
+    {
+        location<std::string> inner_loc(loc.name(), token.unwrap().str());
+        while(inner_loc.iter() != inner_loc.end())
+        {
+            maybe<lex_ws>::invoke(inner_loc); // remove ws if exists
+            if(lex_newline::invoke(inner_loc))
+            {
+                assert(inner_loc.iter() == inner_loc.end());
+                break; // empty line found.
+            }
+            auto com = lex_comment::invoke(inner_loc).unwrap().str();
+            com.erase(com.begin()); // remove # sign
+            comments.push_back(std::move(com));
+            lex_newline::invoke(inner_loc);
+        }
+    }
+
+    table_type data;
     // root object is also a table, but without [tablename]
-    if(auto tab = parse_ml_table(loc))
+    if(auto tab = parse_ml_table<value_type>(loc))
     {
         data = std::move(tab.unwrap());
     }
@@ -1717,14 +1884,14 @@ result<table, std::string> parse_toml_file(location<Container>& loc)
         // message.
         if(const auto tabkey = parse_array_table_key(loc))
         {
-            const auto tab = parse_ml_table(loc);
+            const auto tab = parse_ml_table<value_type>(loc);
             if(!tab){return err(tab.unwrap_err());}
 
             const auto& keys = tabkey.unwrap().first;
             const auto& reg  = tabkey.unwrap().second;
 
             const auto inserted = insert_nested_key(data,
-                    toml::value(tab.unwrap(), reg),
+                    value_type(tab.unwrap(), reg),
                     keys.begin(), keys.end(), reg,
                     /*is_array_of_table=*/ true);
             if(!inserted) {return err(inserted.unwrap_err());}
@@ -1733,14 +1900,14 @@ result<table, std::string> parse_toml_file(location<Container>& loc)
         }
         if(const auto tabkey = parse_table_key(loc))
         {
-            const auto tab = parse_ml_table(loc);
+            const auto tab = parse_ml_table<value_type>(loc);
             if(!tab){return err(tab.unwrap_err());}
 
             const auto& keys = tabkey.unwrap().first;
             const auto& reg  = tabkey.unwrap().second;
 
             const auto inserted = insert_nested_key(data,
-                toml::value(tab.unwrap(), reg), keys.begin(), keys.end(), reg);
+                value_type(tab.unwrap(), reg), keys.begin(), keys.end(), reg);
             if(!inserted) {return err(inserted.unwrap_err());}
 
             continue;
@@ -1748,13 +1915,23 @@ result<table, std::string> parse_toml_file(location<Container>& loc)
         return err(format_underline("[error]: toml::parse_toml_file: "
             "unknown line appeared", {{std::addressof(loc), "unknown format"}}));
     }
-    return ok(data);
+
+    Value v(std::move(data), file);
+    v.comments() = comments;
+
+    return ok(std::move(v));
 }
 
 } // detail
 
-inline table parse(std::istream& is, std::string fname = "unknown file")
+template<typename                     Comment = ::toml::discard_comments,
+         template<typename ...> class Table   = std::unordered_map,
+         template<typename ...> class Array   = std::vector>
+basic_value<Comment, Table, Array>
+parse(std::istream& is, const std::string& fname = "unknown file")
 {
+    using value_type = basic_value<Comment, Table, Array>;
+
     const auto beg = is.tellg();
     is.seekg(0, std::ios::end);
     const auto end = is.tellg();
@@ -1762,7 +1939,8 @@ inline table parse(std::istream& is, std::string fname = "unknown file")
     is.seekg(beg);
 
     // read whole file as a sequence of char
-    std::vector<char> letters(fsize);
+    assert(fsize >= 0);
+    std::vector<char> letters(static_cast<std::size_t>(fsize));
     is.read(letters.data(), fsize);
 
     detail::location<std::vector<char>>
@@ -1784,7 +1962,7 @@ inline table parse(std::istream& is, std::string fname = "unknown file")
         }
     }
 
-    const auto data = detail::parse_toml_file(loc);
+    const auto data = detail::parse_toml_file<value_type>(loc);
     if(!data)
     {
         throw syntax_error(data.unwrap_err());
@@ -1792,14 +1970,17 @@ inline table parse(std::istream& is, std::string fname = "unknown file")
     return data.unwrap();
 }
 
-inline table parse(const std::string& fname)
+template<typename                     Comment = ::toml::discard_comments,
+         template<typename ...> class Table   = std::unordered_map,
+         template<typename ...> class Array   = std::vector>
+basic_value<Comment, Table, Array> parse(const std::string& fname)
 {
     std::ifstream ifs(fname.c_str(), std::ios_base::binary);
     if(!ifs.good())
     {
         throw std::runtime_error("toml::parse: file open error -> " + fname);
     }
-    return parse(ifs, fname);
+    return parse<Comment, Table, Array>(ifs, fname);
 }
 
 } // toml

toml/region.hpp

@@ -9,6 +9,7 @@
 #include <initializer_list>
 #include <iterator>
 #include <iomanip>
+#include <cassert>
 
 namespace toml
 {
@@ -52,6 +53,12 @@ struct region_base
     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
+    // ```
 };
 
 // location represents a position in a container, which contains a file content.
@@ -62,8 +69,9 @@ struct region_base
 template<typename Container>
 struct location final : public region_base
 {
-    using const_iterator = typename Container::const_iterator;
-    using source_ptr     = std::shared_ptr<const Container>;
+    using const_iterator  = typename Container::const_iterator;
+    using difference_type = typename const_iterator::difference_type;
+    using source_ptr      = std::shared_ptr<const Container>;
 
     static_assert(std::is_same<char, typename Container::value_type>::value,"");
     static_assert(std::is_same<std::random_access_iterator_tag,
@@ -96,15 +104,17 @@ struct location final : public region_base
     // 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(std::size_t n = 1) noexcept
+    void advance(difference_type n = 1) noexcept
     {
-        this->line_number_ += std::count(this->iter_, this->iter_ + n, '\n');
+        this->line_number_ += static_cast<std::size_t>(
+                std::count(this->iter_, std::next(this->iter_, n), '\n'));
         this->iter_ += n;
         return;
     }
-    void retrace(std::size_t n = 1) noexcept
+    void retrace(difference_type n = 1) noexcept
     {
-        this->line_number_ -= std::count(this->iter_ - n, this->iter_, '\n');
+        this->line_number_ -= static_cast<std::size_t>(
+                std::count(std::prev(this->iter_, n), this->iter_, '\n'));
         this->iter_ -= n;
         return;
     }
@@ -114,11 +124,13 @@ struct location final : public region_base
         // iterators and returns a negative value if `first > last`.
         if(0 <= std::distance(rollback, this->iter_)) // rollback < iter
         {
-            this->line_number_ -= std::count(rollback, this->iter_, '\n');
+            this->line_number_ -= static_cast<std::size_t>(
+                    std::count(rollback, this->iter_, '\n'));
         }
         else // iter < rollback [[unlikely]]
         {
-            this->line_number_ += std::count(this->iter_, rollback, '\n');
+            this->line_number_ += static_cast<std::size_t>(
+                    std::count(this->iter_, rollback, '\n'));
         }
         this->iter_ = rollback;
         return;
@@ -155,11 +167,15 @@ struct location final : public region_base
     }
     std::size_t before() const noexcept override
     {
-        return std::distance(this->line_begin(), this->iter());
+        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
     {
-        return std::distance(this->iter(), this->line_end());
+        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_;}
@@ -243,15 +259,21 @@ 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
@@ -280,6 +302,114 @@ 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 str = make_string(std::next(comment_found), iter);
+                        if(str.back() == '\r') {str.pop_back();}
+                        com.push_back(std::move(str));
+                    }
+                    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 str = make_string(std::next(comment_found), this->line_end());
+                    if(str.back() == '\r') {str.pop_back();}
+                    com.push_back(std::move(str));
+                }
+            }
+        }
+        return com;
+    }
+
   private:
 
     source_ptr     source_;
@@ -289,47 +419,42 @@ struct region final : public region_base
 
 // to show a better error message.
 inline std::string format_underline(const std::string& message,
-        std::vector<std::pair<region_base const*, std::string>> reg_com,
-        std::vector<std::string> helps = {})
+        const std::vector<std::pair<region_base const*, std::string>>& reg_com,
+        const std::vector<std::string>& helps = {})
 {
     assert(!reg_com.empty());
 
-#ifdef _WIN32
-    const auto newline = "\r\n";
-#else
-    const char newline = '\n';
-#endif
-
-    const auto line_num_width = std::max_element(reg_com.begin(), reg_com.end(),
+    const auto line_num_width = static_cast<int>(std::max_element(
+        reg_com.begin(), reg_com.end(),
         [](std::pair<region_base const*, std::string> const& lhs,
            std::pair<region_base const*, std::string> const& rhs)
         {
             return lhs.first->line_num().size() < rhs.first->line_num().size();
         }
-    )->first->line_num().size();
+    )->first->line_num().size());
 
     std::ostringstream retval;
-    retval << message << newline;
+    retval << message << '\n';
 
-    for(std::size_t i=0; i<reg_com.size(); ++i)
+    for(auto iter = reg_com.begin(); iter != reg_com.end(); ++iter)
     {
-        if(i!=0 && reg_com.at(i-1).first->name() == reg_com.at(i).first->name())
+        // if the filenames are the same, print "..."
+        if(iter != reg_com.begin() &&
+           std::prev(iter)->first->name() == iter->first->name())
         {
-            retval << newline << " ..." << newline;
+            retval << "\n ...\n";
         }
-        else
+        else // if filename differs, print " --> filename.toml"
         {
-            if(i != 0) {retval << newline;}
-            retval << " --> " << reg_com.at(i).first->name() << newline;
+            if(iter != reg_com.begin()) {retval << '\n';}
+            retval << " --> " << iter->first->name() << '\n';
         }
-
-        const region_base* const reg = reg_com.at(i).first;
-        const std::string&   comment = reg_com.at(i).second;
-
+        const region_base* const reg = iter->first;
+        const std::string&   comment = iter->second;
 
         retval << ' ' << std::setw(line_num_width) << reg->line_num();
-        retval << " | " << reg->line() << newline;
-        retval << make_string(line_num_width + 1, ' ');
+        retval << " | " << reg->line() << '\n';
+        retval << make_string(static_cast<std::size_t>(line_num_width + 1), ' ');
         retval << " | " << make_string(reg->before(), ' ');
 
         if(reg->size() == 1)
@@ -346,20 +471,18 @@ inline std::string format_underline(const std::string& message,
             const auto underline_len = std::min(reg->size(), reg->line().size());
             retval << make_string(underline_len, '~');
         }
-
         retval << ' ';
         retval << comment;
     }
 
-    if(helps.size() != 0)
+    if(!helps.empty())
     {
-        retval << newline;
-        retval << make_string(line_num_width + 1, ' ');
+        retval << '\n';
+        retval << make_string(static_cast<std::size_t>(line_num_width + 1), ' ');
         retval << " | ";
         for(const auto help : helps)
         {
-            retval << newline;
-            retval << "Hint: ";
+            retval << "\nHint: ";
             retval << help;
         }
     }

toml/result.hpp

@@ -113,21 +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>
@@ -135,24 +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)
@@ -161,6 +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)
@@ -169,6 +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)
@@ -177,6 +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)
@@ -185,6 +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;
     }
 
@@ -195,6 +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>
@@ -204,6 +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>
@@ -213,6 +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>
@@ -222,6 +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;
     }
 
@@ -233,11 +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())
@@ -246,11 +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;
         }
     }
 
@@ -261,11 +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>
@@ -275,11 +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;
         }
     }
 
@@ -290,11 +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;
@@ -306,11 +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;
@@ -324,11 +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;
@@ -341,11 +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;
@@ -660,5 +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

@@ -10,30 +10,88 @@
 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.
+inline std::string format_key(const toml::key& key)
+{
+    detail::location<toml::key> loc(key, key);
+    detail::lex_unquoted_key::invoke(loc);
+    if(loc.iter() == loc.end())
+    {
+        return key; // all the tokens are consumed. the key is unquoted-key.
+    }
+    std::string token("\"");
+    for(const char c : key)
+    {
+        switch(c)
+        {
+            case '\\': {token += "\\\\"; break;}
+            case '\"': {token += "\\\""; break;}
+            case '\b': {token += "\\b";  break;}
+            case '\t': {token += "\\t";  break;}
+            case '\f': {token += "\\f";  break;}
+            case '\n': {token += "\\n";  break;}
+            case '\r': {token += "\\r";  break;}
+            default  : {token += c;      break;}
+        }
+    }
+    token += "\"";
+    return token;
+}
+
+template<typename Comment,
+         template<typename ...> class Table,
+         template<typename ...> class Array>
 struct serializer
 {
-    serializer(const std::size_t w              = 80,
+    using value_type           = basic_value<Comment, Table, Array>;
+    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        = {})
-        : can_be_inlined_(can_be_inlined), float_prec_(float_prec), width_(w),
-          keys_(std::move(ks))
+        : can_be_inlined_(can_be_inlined), no_comment_(no_comment),
+          float_prec_(float_prec), width_(w), keys_(std::move(ks))
     {}
     ~serializer() = default;
 
-    std::string operator()(const toml::boolean& b) const
+    std::string operator()(const boolean_type& b) const
     {
         return b ? "true" : "false";
     }
-    std::string operator()(const integer i) const
+    std::string operator()(const integer_type i) const
     {
         return std::to_string(i);
     }
-    std::string operator()(const toml::floating f) const
+    std::string operator()(const floating_type f) const
     {
         const auto fmt = "%.*g";
         const auto bsz = std::snprintf(nullptr, 0, fmt, this->float_prec_, f);
-        std::vector<char> buf(bsz + 1, '\0'); // +1 for null character(\0)
+        // +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);
 
         std::string token(buf.begin(), std::prev(buf.end()));
@@ -41,16 +99,27 @@ struct serializer
         {
             token += '0';
         }
-        const auto e = std::find_if(token.cbegin(), token.cend(),
-            [](const char c) -> bool {
-                return c == 'E' || c == 'e';
+
+        const auto e = std::find_if(
+            token.cbegin(), token.cend(), [](const char c) noexcept -> bool {
+                return c == 'e' || c == 'E';
             });
-        if(e == token.cend())
+        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;
+        }
+        if(!has_exponent)
         {
             return token; // there is no exponent part. just return it.
         }
 
-        // zero-prefix in an exponent is not allowed in TOML.
+        // zero-prefix in an exponent is NOT allowed in TOML.
         // remove it if it exists.
         bool        sign_exists = false;
         std::size_t zero_prefix = 0;
@@ -64,11 +133,12 @@ struct serializer
         {
             const auto offset = std::distance(token.cbegin(), e) +
                                (sign_exists ? 2 : 1);
-            token.erase(offset, zero_prefix);
+            token.erase(static_cast<typename std::string::size_type>(offset),
+                        zero_prefix);
         }
         return token;
     }
-    std::string operator()(const string& s) const
+    std::string operator()(const string_type& s) const
     {
         if(s.kind == string_t::basic)
         {
@@ -130,37 +200,44 @@ struct serializer
         }
     }
 
-    std::string operator()(const local_date& d) const
+    std::string operator()(const local_date_type& d) const
     {
         std::ostringstream oss;
         oss << d;
         return oss.str();
     }
-    std::string operator()(const local_time& t) const
+    std::string operator()(const local_time_type& t) const
     {
         std::ostringstream oss;
         oss << t;
         return oss.str();
     }
-    std::string operator()(const local_datetime& dt) const
+    std::string operator()(const local_datetime_type& dt) const
     {
         std::ostringstream oss;
         oss << dt;
         return oss.str();
     }
-    std::string operator()(const offset_datetime& odt) const
+    std::string operator()(const offset_datetime_type& odt) const
     {
         std::ostringstream oss;
         oss << odt;
         return oss.str();
     }
 
-    std::string operator()(const array& v) const
+    std::string operator()(const array_type& v) const
     {
-        if(!v.empty() && v.front().is(value_t::Table))// v is an array of tables
+        if(!v.empty() && v.front().is_table())// v is an array of tables
         {
             // if it's not inlined, we need to add `[[table.key]]`.
-            // but if it can be inlined, we need `table.key = [...]`.
+            // but if it can be inlined,
+            // ```
+            // table.key = [
+            //   {...},
+            //   # comment
+            //   {...},
+            // ]
+            // ```
             if(this->can_be_inlined_)
             {
                 std::string token;
@@ -169,37 +246,62 @@ struct serializer
                     token += this->serialize_key(keys_.back());
                     token += " = ";
                 }
-                bool width_exceeds = false;
+                bool failed = false;
                 token += "[\n";
                 for(const auto& item : v)
                 {
-                    const auto t =
-                        this->make_inline_table(item.cast<value_t::Table>());
+                    // 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;
+                    }
+                    if(!no_comment_)
+                    {
+                        for(const auto& c : item.comments())
+                        {
+                            token += '#';
+                            token += c;
+                            token += '\n';
+                        }
+                    }
+
+                    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())
                     {
-                        width_exceeds = true;
+                        failed = true;
                         break;
                     }
                     token += t;
                     token += ",\n";
                 }
-                if(!width_exceeds)
+                if(!failed)
                 {
                     token += "]\n";
                     return token;
                 }
-                // if width_exceeds, serialize it as [[array.of.tables]].
+                // if failed, serialize them as [[array.of.tables]].
             }
 
             std::string token;
             for(const auto& item : v)
             {
+                if(!no_comment_)
+                {
+                    for(const auto& c : item.comments())
+                    {
+                        token += '#';
+                        token += c;
+                        token += '\n';
+                    }
+                }
                 token += "[[";
                 token += this->serialize_dotted_key(keys_);
                 token += "]]\n";
-                token += this->make_multiline_table(item.cast<value_t::Table>());
+                token += this->make_multiline_table(item.as_table());
             }
             return token;
         }
@@ -208,7 +310,9 @@ struct serializer
             return std::string("[]");
         }
 
-        // not an array of tables. normal array. first, try to make it inline.
+        // 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_ &&
@@ -218,16 +322,54 @@ struct serializer
             }
         }
 
-        // if the length exceeds this->width_, print multiline array
+        // 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)
         {
-            auto next_elem = toml::visit(*this, item);
-            // newline between array-value and comma is not allowed
-            if(next_elem.back() == '\n'){next_elem.pop_back();}
+            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.back() == '\n') {token.pop_back();}
+                token += ",\n";
+                continue;
+            }
+            std::string next_elem;
+            next_elem += toml::visit(*this, item);
 
+            // comma before newline.
+            if(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;
@@ -235,12 +377,13 @@ struct serializer
             }
             else if(current_line.empty())
             {
-                // the next elem cannot be within the width.
+                // if current line was empty, force put the next_elem because
+                // next_elem is not splittable
                 token += next_elem;
                 token += ",\n";
-                // keep current line empty
+                // current_line is kept empty
             }
-            else // current_line has some tokens and it exceeds width
+            else // reset current_line
             {
                 assert(current_line.back() == ',');
                 token += current_line;
@@ -258,9 +401,12 @@ struct serializer
         return token;
     }
 
-    std::string operator()(const table& v) const
+    // templatize for any table-like container
+    std::string operator()(const table_type& v) const
     {
-        if(this->can_be_inlined_)
+        // 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())
@@ -269,7 +415,8 @@ struct serializer
                 token += " = ";
             }
             token += this->make_inline_table(v);
-            if(token.size() < this->width_)
+            if(token.size() < this->width_ &&
+               token.end() == std::find(token.begin(), token.end(), '\n'))
             {
                 return token;
             }
@@ -290,16 +437,7 @@ struct serializer
 
     std::string serialize_key(const toml::key& key) const
     {
-        detail::location<toml::key> loc(key, key);
-        detail::lex_unquoted_key::invoke(loc);
-        if(loc.iter() == loc.end())
-        {
-            return key; // all the tokens are consumed. the key is unquoted-key.
-        }
-        std::string token("\"");
-        token += this->escape_basic_string(key);
-        token += "\"";
-        return token;
+        return ::toml::format_key(key);
     }
 
     std::string serialize_dotted_key(const std::vector<toml::key>& keys) const
@@ -369,8 +507,33 @@ struct serializer
         return retval;
     }
 
-    std::string make_inline_array(const array& v) const
+    // 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;
@@ -384,8 +547,9 @@ struct serializer
         return token;
     }
 
-    std::string make_inline_table(const table& v) const
+    std::string make_inline_table(const table_type& v) const
     {
+        assert(!has_comment_inside(v));
         assert(this->can_be_inlined_);
         std::string token;
         token += '{';
@@ -403,7 +567,7 @@ struct serializer
         return token;
     }
 
-    std::string make_multiline_table(const table& v) const
+    std::string make_multiline_table(const table_type& v) const
     {
         std::string token;
 
@@ -411,11 +575,20 @@ struct serializer
         // remaining non-table values will be assigned into [foo.bar], not [foo]
         for(const auto kv : v)
         {
-            if(kv.second.is(value_t::Table) || is_array_of_tables(kv.second))
+            if(kv.second.is_table() || is_array_of_tables(kv.second))
             {
                 continue;
             }
 
+            if(!kv.second.comments().empty() && !no_comment_)
+            {
+                for(const auto& c : kv.second.comments())
+                {
+                    token += '#';
+                    token += c;
+                    token += '\n';
+                }
+            }
             const auto key_and_sep    = this->serialize_key(kv.first) + " = ";
             const auto residual_width = (this->width_ > key_and_sep.size()) ?
                                         this->width_ - key_and_sep.size() : 0;
@@ -438,7 +611,7 @@ struct serializer
         bool multiline_table_printed = false;
         for(const auto& kv : v)
         {
-            if(!kv.second.is(value_t::Table) && !is_array_of_tables(kv.second))
+            if(!kv.second.is_table() && !is_array_of_tables(kv.second))
             {
                 continue; // other stuff are already serialized. skip them.
             }
@@ -446,8 +619,8 @@ struct serializer
             std::vector<toml::key> ks(this->keys_);
             ks.push_back(kv.first);
 
-            auto tmp = visit(serializer(
-                this->width_, this->float_prec_, !multiline_table_printed, ks),
+            auto tmp = visit(serializer(this->width_, this->float_prec_,
+                !multiline_table_printed, this->no_comment_, ks),
                 kv.second);
 
             if((!multiline_table_printed) &&
@@ -460,66 +633,132 @@ struct serializer
                 // still inline tables only.
                 tmp += '\n';
             }
+
+            if(!kv.second.comments().empty() && !no_comment_)
+            {
+                for(const auto& c : kv.second.comments())
+                {
+                    token += '#';
+                    token += c;
+                    token += '\n';
+                }
+            }
             token += tmp;
         }
         return token;
     }
 
-    bool is_array_of_tables(const value& v) const
+    bool is_array_of_tables(const value_type& v) const
     {
-        if(!v.is(value_t::Array)) {return false;}
-
-        const auto& a = v.cast<value_t::Array>();
-        return !a.empty() && a.front().is(value_t::Table);
+        if(!v.is_array()) {return false;}
+        const auto& a = v.as_array();
+        return !a.empty() && a.front().is_table();
     }
 
   private:
 
     bool        can_be_inlined_;
+    bool        no_comment_;
     int         float_prec_;
     std::size_t width_;
     std::vector<toml::key> keys_;
 };
 
-inline std::string
-format(const value& v, std::size_t w = 80,
+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 force_inline = false)
+       bool no_comment = false, bool force_inline = false)
 {
     // if value is a table, it is considered to be a root object.
-    // the root object can't be an inline table. so pass false. otherwise, true.
-    return visit(serializer(w, fprec, (!v.is_table()) || force_inline), v);
+    // 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
+        }
+        oss << visit(serializer<C, M, V>(w, fprec, no_comment, false), v);
+        return oss.str();
+    }
+    return visit(serializer<C, M, V>(w, fprec, force_inline), v);
 }
-inline std::string
-format(const table& t, std::size_t w = 80,
-       int fprec = std::numeric_limits<toml::floating>::max_digits10,
-       bool force_inline = false)
+
+namespace detail
 {
-    return serializer(w, fprec, force_inline)(t);
+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 defalut, it shows comments.
+    os.iword(detail::comment_index(os)) = 1;
+    return os;
 }
 
 template<typename charT, typename traits>
 std::basic_ostream<charT, traits>&
-operator<<(std::basic_ostream<charT, traits>& os, const value& v)
+showcomment(std::basic_ostream<charT, traits>& os)
 {
-    // get status of std::setw().
-    const std::size_t w     = os.width();
-    const int         fprec = os.precision();
-    os.width(0);
-    // the root object can't be an inline table. so pass `false`.
-    os << visit(serializer(w, fprec, false), v);
+    // by default, it is zero. and by defalut, it shows comments.
+    os.iword(detail::comment_index(os)) = 0;
     return os;
 }
-template<typename charT, typename traits>
+
+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 table& v)
+operator<<(std::basic_ostream<charT, traits>& os, const basic_value<C, M, V>& v)
 {
     // get status of std::setw().
-    const std::size_t w     = os.width();
-    const int         fprec = os.precision();
+    const auto w     = static_cast<std::size_t>(os.width());
+    const int  fprec = static_cast<int>(os.precision());
     os.width(0);
+
+    // by defualt, iword is initialized byl 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`.
-    os << serializer(w, fprec, false)(v);
+    os << visit(serializer<C, M, V>(w, fprec, false, no_comment), v);
+
+    // 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/source_location.hpp

@@ -0,0 +1,82 @@
+//     Copyright Toru Niina 2019.
+// Distributed under the MIT License.
+#ifndef TOML11_SOURCE_LOCATION_HPP
+#define TOML11_SOURCE_LOCATION_HPP
+#include "region.hpp"
+#include <cstdint>
+
+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_(0), column_num_(0), region_size_(0),
+          file_name_("unknown file"), line_str_("")
+    {}
+
+    explicit source_location(const detail::region_base* reg)
+        : line_num_(0), column_num_(0), region_size_(0),
+          file_name_("unknown file"), line_str_("")
+    {
+        if(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();
+        }
+    }
+
+    ~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_;
+};
+
+} // toml
+#endif// TOML11_SOURCE_LOCATION_HPP

toml/string.hpp

@@ -4,6 +4,11 @@
 #define TOML11_STRING_HPP
 #include <string>
 #include <cstdint>
+#if __cplusplus >= 201703L
+#if __has_include(<string_view>)
+#include <string_view>
+#endif
+#endif
 
 namespace toml
 {
@@ -40,6 +45,17 @@ struct string
     operator std::string const& () const& noexcept {return str;}
     operator std::string&&      () &&     noexcept {return std::move(str);}
 
+#if __cplusplus >= 201703L
+    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);}
+#endif
+
     string_t    kind;
     std::string str;
 };
@@ -123,9 +139,74 @@ 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/traits.hpp

@@ -6,18 +6,20 @@
 #include <utility>
 #include <chrono>
 #include <tuple>
+#include <string>
+#if __cplusplus >= 201703L
+#if __has_include(<string_view>)
+#include <string_view>
+#endif // has_include(<string_view>)
+#endif // cplusplus   >= C++17
 
 namespace toml
 {
-
-class value; // forward decl
+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
 
@@ -48,12 +50,22 @@ struct has_resize_method_impl
     template<typename T> static std::false_type check(...);
 };
 
+struct is_comparable_impl
+{
+    template<typename T> static std::true_type  check(decltype(std::declval<T>() < std::declval<T>())*);
+    template<typename T> static std::false_type check(...);
+};
+
 struct has_from_toml_method_impl
 {
-    template<typename T>
+    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::value>()))*);
-    template<typename T>
+        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
@@ -80,11 +92,14 @@ 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)){};
-
-
 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>(nullptr)){};
+: 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)){};
@@ -114,7 +129,7 @@ template<typename T>
 struct negation : std::integral_constant<bool, !static_cast<bool>(T::value)>{};
 
 // ---------------------------------------------------------------------------
-// normal type checker
+// type checkers
 
 template<typename T> struct is_std_pair : std::false_type{};
 template<typename T1, typename T2>
@@ -128,6 +143,42 @@ 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{};
 
+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 __cplusplus >= 201703L
+    negation<std::is_same<T, std::string_view>>, // not a std::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
 
@@ -154,6 +205,11 @@ struct index_sequence_maker<0>
 template<std::size_t N>
 using make_index_sequence = typename index_sequence_maker<N-1>::type;
 
+// ---------------------------------------------------------------------------
+// C++14 enable_if_t
+template<bool B, typename T>
+using enable_if_t = typename std::enable_if<B, T>::type;
+
 // ---------------------------------------------------------------------------
 // return_type_of_t
 

toml/types.hpp

@@ -5,50 +5,51 @@
 #include "datetime.hpp"
 #include "string.hpp"
 #include "traits.hpp"
+#include "comments.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>;
+using boolean        = bool;
+using integer        = std::int64_t;
+using floating       = double; // "float" is a keyward, 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
 
-// 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;
+// 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;
 
 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,
 };
 
 template<typename charT, typename traits>
@@ -57,27 +58,27 @@ 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();
 }
@@ -85,101 +86,63 @@ 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>
+// 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

toml/utility.hpp

@@ -79,7 +79,7 @@ std::string concat_to_string(Ts&& ... args)
 template<typename T, typename U>
 T from_string(const std::string& str, U&& opt)
 {
-    T v(std::forward<U>(opt));
+    T v(static_cast<T>(std::forward<U>(opt)));
     std::istringstream iss(str);
     iss >> v;
     return v;