chore: update minor version

to remove conversions

.circleci/config.yml

@@ -12,7 +12,7 @@ jobs:
           command: |
               g++ --version
               cd tests/
-              g++ -std=c++11 -O2 -Wall -Wextra -Werror -I../ check_toml_test.cpp -o check_toml_test
+              g++ -std=c++11 -O2 -Wall -Wextra -Werror -DTOML11_COLORIZE_ERROR_MESSAGE -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:
@@ -24,7 +24,7 @@ jobs:
           command: |
               g++ --version
               cd tests/
-              g++ -std=c++11 -O2 -Wall -Wextra -Wpedantic -Werror -I../ check_serialization.cpp -o check_serialization
+              g++ -std=c++11 -O2 -Wall -Wextra -Wpedantic -Werror -DTOML11_COLORIZE_ERROR_MESSAGE -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
@@ -47,7 +47,7 @@ jobs:
           command: |
               g++ --version
               cd tests/
-              g++ -std=c++11 -O2 -Wall -Wextra -Wpedantic -Werror -I../ check.cpp -o check
+              g++ -std=c++11 -O2 -Wall -Wextra -Wpedantic -Werror -DTOML11_COLORIZE_ERROR_MESSAGE -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

.travis.yml

@@ -9,7 +9,7 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
         - sourceline: 'ppa:mhier/libboost-latest'
         packages:
         - g++-5
@@ -21,7 +21,7 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
         - sourceline: 'ppa:mhier/libboost-latest'
         packages:
         - g++-6
@@ -33,7 +33,7 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
         - sourceline: 'ppa:mhier/libboost-latest'
         packages:
         - g++-7
@@ -45,7 +45,31 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
+        - sourceline: 'ppa:mhier/libboost-latest'
+        packages:
+        - g++-8
+        - boost1.70
+  - os: linux
+    language: cpp
+    compiler: gcc
+    env: COMPILER="g++-8" CXX_STANDARD=11 TOML_HEAD=ON
+    addons:
+      apt:
+        sources:
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
+        - sourceline: 'ppa:mhier/libboost-latest'
+        packages:
+        - g++-8
+        - boost1.70
+  - os: linux
+    language: cpp
+    compiler: gcc
+    env: COMPILER="g++-8" CXX_STANDARD=14
+    addons:
+      apt:
+        sources:
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
         - sourceline: 'ppa:mhier/libboost-latest'
         packages:
         - g++-8
@@ -57,7 +81,19 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
+        - sourceline: 'ppa:mhier/libboost-latest'
+        packages:
+        - g++-8
+        - boost1.70
+  - os: linux
+    language: cpp
+    compiler: gcc
+    env: COMPILER="g++-8" CXX_STANDARD=17 TOML_HEAD=ON
+    addons:
+      apt:
+        sources:
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
         - sourceline: 'ppa:mhier/libboost-latest'
         packages:
         - g++-8
@@ -65,16 +101,16 @@ matrix:
   - os: linux
     language: cpp
     compiler: clang
-    env: COMPILER="clang++-3.7" CXX_STANDARD=11
+    env: COMPILER="clang++-3.9" CXX_STANDARD=11
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
-        - llvm-toolchain-precise-3.7
         - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-3.9
         packages:
         - g++-8
-        - clang-3.7
+        - clang-3.9
         - boost1.70
   - os: linux
     language: cpp
@@ -83,9 +119,9 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
-        - llvm-toolchain-trusty-4.0
         - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-4.0
         packages:
         - g++-8
         - clang-4.0
@@ -97,9 +133,9 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
-        - llvm-toolchain-trusty-5.0
         - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-5.0
         packages:
         - g++-8
         - clang-5.0
@@ -111,9 +147,9 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
-        - llvm-toolchain-trusty-6.0
         - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-6.0
         packages:
         - g++-8
         - clang-6.0
@@ -125,9 +161,9 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
-        - llvm-toolchain-trusty-7
         - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-7
         packages:
         - g++-8
         - clang-7
@@ -139,13 +175,41 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
-        - llvm-toolchain-trusty-8
         - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-8
         packages:
         - g++-8
         - clang-8
         - boost1.70
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-8" CXX_STANDARD=11 TOML_HEAD=ON
+    addons:
+      apt:
+        sources:
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
+        - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-8
+        packages:
+        - g++-8
+        - clang-8
+        - boost1.70
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-8" CXX_STANDARD=14
+    addons:
+      apt:
+        sources:
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
+        - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-8
+        packages:
+        - clang-8
+        - g++-8
+        - boost1.70
   - os: linux
     language: cpp
     compiler: clang
@@ -153,9 +217,51 @@ matrix:
     addons:
       apt:
         sources:
-        - ubuntu-toolchain-r-test
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
-        - llvm-toolchain-trusty-8
         - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-8
+        packages:
+        - clang-8
+        - g++-8
+        - boost1.70
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-8" CXX_STANDARD=17 TOML_HEAD=ON
+    addons:
+      apt:
+        sources:
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
+        - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-8
+        packages:
+        - clang-8
+        - g++-8
+        - boost1.70
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-8" CXX_STANDARD=11 WITH_ASAN=ON
+    addons:
+      apt:
+        sources:
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
+        - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-8
+        packages:
+        - clang-8
+        - g++-8
+        - boost1.70
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-8" CXX_STANDARD=11 WITH_UBSAN=ON
+    addons:
+      apt:
+        sources:
+        - sourceline: 'ppa:ubuntu-toolchain-r/test'
+        - sourceline: 'ppa:mhier/libboost-latest'
+        - llvm-toolchain-trusty-8
         packages:
         - clang-8
         - g++-8
@@ -164,6 +270,15 @@ matrix:
     language: cpp
     compiler: clang
     env: CXX_STANDARD=11
+    cache:
+      directories:
+        - $HOME/Library/Caches/Homebrew
+    addons:
+      homebrew:
+        update: true
+        packages:
+        - cmake
+        - boost
 
 script:
 - |
@@ -172,13 +287,33 @@ script:
     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
+- |
+  if [[ "${TOML_HEAD}" != "ON" ]]; then
+    export TOML_HEAD="OFF"
+  fi
+- echo "TOML_HEAD = ${TOML_HEAD}"
+- |
+  if [[ "${WITH_ASAN}" != "ON" ]]; then
+    export WITH_ASAN="OFF"
+  fi
+- echo "WITH_ASAN = ${WITH_ASAN}"
+- |
+  if [[ "${WITH_UBSAN}" != "ON" ]]; then
+    export WITH_UBSAN="OFF"
+  fi
+- echo "WITH_UBSAN = ${WITH_UBSAN}"
 - cmake --version
 - mkdir build
 - cd build
 - git clone https://github.com/toml-lang/toml.git
-- cmake -DCMAKE_CXX_COMPILER=$COMPILER -DCMAKE_CXX_STANDARD=$CXX_STANDARD ..
+- cmake -DCMAKE_CXX_COMPILER=$COMPILER -DCMAKE_CXX_STANDARD=$CXX_STANDARD -DTOML11_USE_UNRELEASED_TOML_FEATURES=${TOML_HEAD} -Dtoml11_TEST_WITH_ASAN=${WITH_ASAN} -Dtoml11_TEST_WITH_UBSAN=${WITH_UBSAN} ..
 - make
 - ctest --output-on-failure
+
+# https://stackoverflow.com/a/53331571
+before_cache:
+- |
+  if [[ "${TRAVIS_OS_NAME}" == "osx" ]]; then
+    brew cleanup
+  fi

CMakeLists.txt

@@ -4,13 +4,15 @@ enable_testing()
 project(toml11)
 
 set(toml11_VERSION_MAYOR  3)
-set(toml11_VERSION_MINOR  0)
+set(toml11_VERSION_MINOR  3)
-set(toml11_VERSION_PATCH  1)
+set(toml11_VERSION_PATCH  0)
 set(toml11_VERSION
   "${toml11_VERSION_MAYOR}.${toml11_VERSION_MINOR}.${toml11_VERSION_PATCH}"
 )
 
 option(toml11_BUILD_TEST "Build toml tests" ON)
+option(toml11_TEST_WITH_ASAN  "use LLVM address sanitizer" OFF)
+option(toml11_TEST_WITH_UBSAN "use LLVM undefined behavior sanitizer" OFF)
 
 include(CheckCXXCompilerFlag)
 if("${CMAKE_VERSION}" VERSION_GREATER 3.1)

README.md

@@ -68,8 +68,12 @@ int main()
 - [TOML literal](#toml-literal)
 - [Conversion between toml value and arbitrary types](#conversion-between-toml-value-and-arbitrary-types)
 - [Formatting user-defined error messages](#formatting-user-defined-error-messages)
+- [Obtaining location information](#obtaining-location-information)
+- [Exceptions](#exceptions)
+- [Colorize Error Messages](#colorize-error-messages)
 - [Serializing TOML data](#serializing-toml-data)
 - [Underlying types](#underlying-types)
+- [Unreleased TOML features](#unreleased-toml-features)
 - [Breaking Changes from v2](#breaking-changes-from-v2)
 - [Running Tests](#running-tests)
 - [Contributors](#contributors)
@@ -270,10 +274,44 @@ const auto color = toml::find<std::string>(data, "fruit", "physical", "color");
 const auto shape = toml::find<std::string>(data, "fruit", "physical", "shape");
 ```
 
+### Finding a value in an array
+
+You can find n-th value in an array by `toml::find`.
+
+```toml
+values = ["foo", "bar", "baz"]
+```
+
+``` cpp
+const auto data   = toml::parse("sample.toml");
+const auto values = toml::find(data, "values");
+const auto bar    = toml::find<std::string>(values, 1);
+```
+
+`toml::find` can also search array recursively.
+
+```cpp
+const auto data = toml::parse("fruit.toml");
+const auto bar  = toml::find<std::string>(data, "values", 1);
+```
+
+Before calling `toml::find`, you can check if a value corresponding to a key
+exists. You can use both `bool toml::value::contains(const key&) const` and
+`std::size_t toml::value::count(const key&) const`. Those behaves like the
+`std::map::contains` and `std::map::count`.
+
+```cpp
+const auto data = toml::parse("fruit.toml");
+if(data.contains("fruit") && data.at("fruit").count("physical") != 0)
+{
+    // ...
+}
+```
+
 ### In case of error
 
-If the value does not exist, `toml::find` throws an error with the location of
+If the value does not exist, `toml::find` throws `std::out_of_range` with the
-the table.
+location of the table.
 
 ```console
 terminate called after throwing an instance of 'std::out_of_range'
@@ -283,11 +321,6 @@ terminate called after throwing an instance of 'std::out_of_range'
    | ~~~~~ in this table
 ```
 
-**Note**: It is recommended to find a table as `toml::value` because it has much information
-compared to `toml::table`, which is an alias of
-`std::unordered_map<std::string, toml::value>`. Since `toml::table` does not have
-any information about toml file, such as where the table was defined in the file.
-
 ----
 
 If the specified type differs from the actual value contained, it throws
@@ -350,6 +383,7 @@ The above code works with the following toml file.
 # NOT {"physical": {"color": "orange"}}.
 ```
 
+
 ## Casting a toml value
 
 ### `toml::get`
@@ -453,6 +487,60 @@ class value {
 } // toml
 ```
 
+### `at()`
+
+You can access to the element of a table and an array by `toml::basic_value::at`.
+
+```cpp
+const toml::value v{1,2,3,4,5};
+std::cout << v.at(2).as_integer() << std::endl; // 3
+
+const toml::value v{{"foo", 42}, {"bar", 3.14}};
+std::cout << v.at("foo").as_integer() << std::endl; // 42
+```
+
+If an invalid key (integer for a table, string for an array), it throws
+`toml::type_error` for the conversion. If the provided key is out-of-range,
+it throws `std::out_of_range`.
+
+Note that, although `std::string` has `at()` member function, `toml::value::at`
+throws if the contained type is a string. Because `std::string` does not
+contain `toml::value`.
+
+### `operator[]`
+
+You can also access to the element of a table and an array by
+`toml::basic_value::operator[]`.
+
+```cpp
+const toml::value v{1,2,3,4,5};
+std::cout << v[2].as_integer() << std::endl; // 3
+
+const toml::value v{{"foo", 42}, {"bar", 3.14}};
+std::cout << v["foo"].as_integer() << std::endl; // 42
+```
+
+When you access to a `toml::value` that is not initialized yet via
+`operator[](const std::string&)`, the `toml::value` will be a table,
+just like the `std::map`.
+
+```cpp
+toml::value v; // not initialized as a table.
+v["foo"] = 42; // OK. `v` will be a table.
+```
+
+Contrary, if you access to a `toml::value` that contains an array via `operator[]`,
+it does not check anything. It converts `toml::value` without type check and then
+access to the n-th element without boundary check, just like the `std::vector::operator[]`.
+
+```cpp
+toml::value v; // not initialized as an array
+v[2] = 42;     // error! UB
+```
+
+Please make sure that the `toml::value` has an array inside when you access to
+its element via `operator[]`.
+
 ## Checking value type
 
 You can check the type of a value by `is_xxx` function.
@@ -675,6 +763,7 @@ date information, but it can be converted to `std::chrono::duration` that
 represents a duration from the beginning of the day, `00:00:00.000`.
 
 ```toml
+# sample.toml
 date = 2018-12-23
 time = 12:30:00
 l_dt = 2018-12-23T12:30:00
@@ -691,8 +780,12 @@ const auto o_dt = toml::get<std::chrono::system_clock::time_point>(data.at("o_dt
 const auto time = toml::get<std::chrono::minutes>(data.at("time")); // 12 * 60 + 30 min
 ```
 
-toml11 defines its own datetime classes.
+`local_date` and `local_datetime` are assumed to be in the local timezone when
-You can see the definitions in [toml/datetime.hpp](toml/datetime.hpp).
+they are converted into `time_point`. On the other hand, `offset_datetime` only
+uses the offset part of the data and it does not take local timezone into account.
+
+To contain datetime data, toml11 defines its own datetime types.
+For more detail, you can see the definitions in [toml/datetime.hpp](toml/datetime.hpp).
 
 ## Getting with a fallback
 
@@ -805,14 +898,25 @@ toml::value v(toml::local_time(std::chrono::hours(10)));
 ```
 
 You can construct an array object not only from `initializer_list`, but also
-from STL containers.
+from STL containers. In that case, the element type must be convertible to
+`toml::value`.
 
 ```cpp
 std::vector<int> vec{1,2,3,4,5};
-toml::value v = vec;
+toml::value v(vec);
 ```
 
-All the elements of `initializer_list` should be convertible into `toml::value`.
+When you construct an array value, all the elements of `initializer_list`
+must be convertible into `toml::value`.
+
+If a `toml::value` has an array, you can `push_back` an element in it.
+
+```cpp
+toml::value v{1,2,3,4,5};
+v.push_back(6);
+```
+
+`emplace_back` also works.
 
 ## Preserving comments
 
@@ -1029,7 +1133,7 @@ const auto data = toml::parse("example.toml");
 const foo f = toml::find<ext::foo>(data, "foo");
 ```
 
-There are 2 ways to use `toml::get` with the types that you defined.
+There are 3 ways to use `toml::get` with the types that you defined.
 
 The first one is to implement `from_toml(const toml::value&)` member function.
 
@@ -1056,7 +1160,31 @@ struct foo
 In this way, because `toml::get` first constructs `foo` without arguments,
 the type should be default-constructible.
 
-The second is to implement specialization of `toml::from` for your type.
+The second is to implement `constructor(const toml::value&)`.
+
+```cpp
+namespace ext
+{
+struct foo
+{
+    explicit foo(const toml::value& v)
+        : a(toml::find<int>(v, "a")), b(toml::find<double>(v, "b")),
+          c(toml::find<std::string>(v, "c"))
+    {}
+
+    int         a;
+    double      b;
+    std::string c;
+};
+} // ext
+```
+
+Note that implicit default constructor declaration will be suppressed
+when a constructor is defined. If you want to use the struct (here, `foo`)
+in a container (e.g. `std::vector<foo>`), you may need to define default
+constructor explicitly.
+
+The third is to implement specialization of `toml::from` for your type.
 
 ```cpp
 namespace ext
@@ -1074,7 +1202,7 @@ namespace toml
 template<>
 struct from<ext::foo>
 {
-    ext::foo from_toml(const value& v)
+    static ext::foo from_toml(const value& v)
     {
         ext::foo f;
         f.a = find<int        >(v, "a");
@@ -1114,7 +1242,7 @@ template<>
 struct from<ext::foo>
 {
     template<typename C, template<typename ...> class M, template<typename ...> class A>
-    ext::foo from_toml(const basic_value<C, M, A>& v)
+    static ext::foo from_toml(const basic_value<C, M, A>& v)
     {
         ext::foo f;
         f.a = find<int        >(v, "a");
@@ -1170,7 +1298,7 @@ namespace toml
 template<>
 struct into<ext::foo>
 {
-    toml::table into_toml(const ext::foo& f)
+    static toml::table into_toml(const ext::foo& f)
     {
         return toml::table{{"a", f.a}, {"b", f.b}, {"c", f.c}};
     }
@@ -1237,7 +1365,28 @@ you will get an error message like this.
    |       ~~ maximum number here
 ```
 
-### Obtaining location information
+You can print hints at the end of the message.
+
+```cpp
+std::vector<std::string> hints;
+hints.push_back("positive number means n >= 0.");
+hints.push_back("negative number is not positive.");
+std::cerr << toml::format_error("[error] value should be positive",
+                                data.at("num"), "positive number required", hints)
+          << std::endl;
+```
+
+```console
+[error] value should be positive
+ --> example.toml
+ 2 | num = 42
+   |       ~~ positive number required
+   |
+Hint: positive number means n >= 0.
+Hint: negative number is not positive.
+```
+
+## Obtaining location information
 
 You can also format error messages in your own way by using `source_location`.
 
@@ -1262,6 +1411,92 @@ const toml::value           v   = /*...*/;
 const toml::source_location loc = v.location();
 ```
 
+## Exceptions
+
+All the exceptions thrown by toml11 inherits `toml::exception` that inherits
+`std::exception`.
+
+```cpp
+namespace toml {
+struct exception      : public std::exception  {/**/};
+struct syntax_error   : public toml::exception {/**/};
+struct type_error     : public toml::exception {/**/};
+struct internal_error : public toml::exception {/**/};
+} // toml
+```
+
+`toml::exception` has `toml::exception::location()` member function that returns
+`toml::source_location`, in addition to `what()`.
+
+```cpp
+namespace toml {
+struct exception : public std::exception
+{
+    // ...
+    source_location const& location() const noexcept;
+};
+} // toml
+```
+
+It represents where the error occurs.
+
+## Colorize Error Messages
+
+By defining `TOML11_COLORIZE_ERROR_MESSAGE`, the error messages from
+`toml::parse` and `toml::find|get` will be colorized. By default, this feature
+is turned off.
+
+With the following toml file taken from `toml-lang/toml/tests/hard_example.toml`,
+
+```toml
+[error]
+array = [
+         "This might most likely happen in multiline arrays",
+         Like here,
+         "or here,
+         and here"
+        ]     End of array comment, forgot the #
+```
+
+the error message would be like this.
+
+![error-message-1](https://github.com/ToruNiina/toml11/blob/misc/misc/toml11-err-msg-1.png)
+
+With the following,
+
+```toml
+[error]
+# array = [
+#          "This might most likely happen in multiline arrays",
+#          Like here,
+#          "or here,
+#          and here"
+#         ]     End of array comment, forgot the #
+number = 3.14  pi <--again forgot the #
+```
+
+the error message would be like this.
+
+![error-message-2](https://github.com/ToruNiina/toml11/blob/misc/misc/toml11-err-msg-2.png)
+
+The message would be messy when it is written to a file, not a terminal because
+it uses [ANSI escape code](https://en.wikipedia.org/wiki/ANSI_escape_code).
+
+Without `TOML11_COLORIZE_ERROR_MESSAGE`, you can still colorize user-defined
+error message by passing `true` to the `toml::format_error` function.
+If you define `TOML11_COLORIZE_ERROR_MESSAGE`, the value is `true` by default.
+If not, the defalut value would be `false`.
+
+```cpp
+std::cerr << toml::format_error("[error] value should be positive",
+                                data.at("num"), "positive number required",
+                                hints, /*colorize = */ true) << std::endl;
+```
+
+Note: It colorize `[error]` in red. That means that it detects `[error]` prefix
+at the front of the error message. If there is no `[error]` prefix,
+`format_error` adds it to the error message.
+
 ## Serializing TOML data
 
 toml11 enables you to serialize data into toml format.
@@ -1394,7 +1629,83 @@ This feature is introduced to make it easy to write a custom serializer.
 Because `std::chrono::system_clock::time_point` is a __time point__,
 not capable of representing a Local Time independent from a specific day.
 
-It is recommended to get `datetime`s as `std::chrono` classes through `toml::get`.
+## Unreleased TOML features
+
+There are some unreleased features in toml-lang/toml:master.
+Currently, the following features are available after defining
+`TOML11_USE_UNRELEASED_TOML_FEATURES` macro flag.
+
+To use those features, `#define` `TOML11_USE_UNRELEASED_TOML_FEATURES` before
+including `toml.hpp` or pass `-DTOML11_USE_UNRELEASED_TOML_FEATURES` to your
+compiler.
+
+- Leading zeroes in exponent parts of floats are permitted.
+  - e.g. `1.0e+01`, `5e+05`
+  - [toml-lang/toml/PR/656](https://github.com/toml-lang/toml/pull/656)
+- Allow raw tab characters in basic strings and multi-line basic strings.
+  - [toml-lang/toml/PR/627](https://github.com/toml-lang/toml/pull/627)
+- Allow heterogeneous arrays
+  - [toml-lang/toml/PR/676](https://github.com/toml-lang/toml/pull/676)
+
+### Note about heterogeneous arrays
+
+Although `toml::parse` allows heterogeneous arrays, constructor of `toml::value`
+does not.
+
+```cpp
+// this won't be compiled
+toml::value v{
+    "foo", 3.14, 42, {1,2,3,4,5}, {{"key", "value"}}
+}
+```
+
+There is a workaround for this issue. By explicitly converting values into
+`toml::value`, you can initialize `toml::value` with a heterogeneous array.
+
+```cpp
+// OK!
+toml::value v{
+    toml::value("foo"), toml::value(3.14), toml::value(42),
+    toml::value{1,2,3,4,5}, toml::value{{"key", "value"}}
+}
+```
+
+The reason why the first example is not allowed is the following.
+Let's assume that you are initializing a `toml::value` with a table.
+
+```cpp
+                    // # expecting TOML table.
+toml::value v{      // [v]
+    {"answer", 42}, // answer = 42
+    {"pi",   3.14}, // pi = 3.14
+    {"foo", "bar"}  // foo = "bar"
+};
+```
+
+This is indistinguishable from a (heterogeneous) TOML array definition.
+
+```toml
+v = [
+    ["answer", 42],
+    ["pi",   3.14],
+    ["foo", "bar"],
+]
+```
+
+This means that the above C++ code makes constructor's overload resolution
+ambiguous. So a constructor that allows both "table as an initializer-list" and
+"heterogeneous array as an initializer-list" cannot be implemented.
+
+Thus, although it is painful, you need to explicitly cast values into
+`toml::value` when you initialize heterogeneous array in C++ code.
+
+```cpp
+// You need to do this when you want to initialize hetero array.
+toml::value v{
+    toml::value("foo"), toml::value(3.14), toml::value(42),
+    toml::value{1,2,3,4,5}, toml::value{{"key", "value"}}
+}
+```
 
 ## Breaking Changes from v2
 
@@ -1465,11 +1776,18 @@ I appreciate the help of the contributors who introduced the great feature to th
   - Fixed warnings while type conversion
 - @KerstinKeller
   - Added installation script to CMake
+- J.C. Moyer (@jcmoyer)
+  - Fixed an example code in the documentation
+- Jt Freeman (@blockparty-sh)
+  - Fixed feature test macro around `localtime_s`
+  - Suppress warnings in Debug mode
+- OGAWA Kenichi (@kenichiice)
+  - Suppress warnings on intel compiler
 
 ## Licensing terms
 
 This product is licensed under the terms of the [MIT License](LICENSE).
 
-- Copyright (c) 2017-2019 Toru Niina
+- Copyright (c) 2017-2020 Toru Niina
 
 All rights reserved.

tests/CMakeLists.txt

@@ -39,6 +39,15 @@ set(TEST_NAMES
 CHECK_CXX_COMPILER_FLAG("-Wall"      COMPILER_SUPPORTS_WALL)
 CHECK_CXX_COMPILER_FLAG("-Wextra"    COMPILER_SUPPORTS_WEXTRA)
 CHECK_CXX_COMPILER_FLAG("-Wpedantic" COMPILER_SUPPORTS_WPEDANTIC)
+CHECK_CXX_COMPILER_FLAG("-Werror"    COMPILER_SUPPORTS_WERROR)
+
+CHECK_CXX_COMPILER_FLAG("-Wsign-conversion"     COMPILER_SUPPORTS_WSIGN_CONVERSION)
+CHECK_CXX_COMPILER_FLAG("-Wconversion"          COMPILER_SUPPORTS_WCONVERSION)
+CHECK_CXX_COMPILER_FLAG("-Wduplicated-cond"     COMPILER_SUPPORTS_WDUPLICATED_COND)
+CHECK_CXX_COMPILER_FLAG("-Wduplicated-branches" COMPILER_SUPPORTS_WDUPLICATED_BRANCHES)
+CHECK_CXX_COMPILER_FLAG("-Wlogical-op"          COMPILER_SUPPORTS_WLOGICAL_OP)
+CHECK_CXX_COMPILER_FLAG("-Wuseless-cast"        COMPILER_SUPPORTS_WUSELESS_CAST)
+CHECK_CXX_COMPILER_FLAG("-Wdouble-promotion"    COMPILER_SUPPORTS_WDOUBLE_PROMOTION)
 
 if(COMPILER_SUPPORTS_WALL)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
@@ -49,6 +58,38 @@ endif()
 if(COMPILER_SUPPORTS_WPEDANTIC)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wpedantic")
 endif()
+if(COMPILER_SUPPORTS_WERROR)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
+endif()
+if(COMPILER_SUPPORTS_WSIGN_CONVERSION)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-conversion")
+endif()
+if(COMPILER_SUPPORTS_WCONVERSION)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wconversion")
+endif()
+if(COMPILER_SUPPORTS_WDUPLICATED_COND)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wduplicated-cond")
+endif()
+if(COMPILER_SUPPORTS_WDUPLICATED_BRANCHES)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wduplicated-branches")
+endif()
+if(COMPILER_SUPPORTS_WLOGICAL_OP)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wlogical-op")
+endif()
+if(COMPILER_SUPPORTS_WUSELESS_CAST)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wuseless-cast")
+endif()
+if(COMPILER_SUPPORTS_WDOUBLE_PROMOTION)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wdouble-promotion")
+endif()
+
+option(TOML11_USE_UNRELEASED_TOML_FEATURES
+    "use features in toml-lang/toml master while testing" OFF)
+
+if(TOML11_USE_UNRELEASED_TOML_FEATURES)
+    message(STATUS "adding TOML11_USE_UNRELEASED_TOML_FEATURES flag")
+    add_definitions("-DTOML11_USE_UNRELEASED_TOML_FEATURES")
+endif()
 
 # Disable some MSVC warnings
 if(MSVC)
@@ -96,6 +137,19 @@ foreach(TEST_NAME ${TEST_NAMES})
     add_executable(${TEST_NAME} ${TEST_NAME}.cpp)
     target_link_libraries(${TEST_NAME} ${Boost_UNIT_TEST_FRAMEWORK_LIBRARY} toml11::toml11)
     target_include_directories(${TEST_NAME} PRIVATE ${Boost_INCLUDE_DIRS})
+
+    if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
+        if(toml11_TEST_WITH_ASAN)
+            set_target_properties(${TEST_NAME} PROPERTIES
+                COMPILE_FLAGS "-fsanitize=address -fno-omit-frame-pointer"
+                LINK_FLAGS    "-fsanitize=address -fno-omit-frame-pointer")
+        elseif(toml11_TEST_WITH_UBSAN)
+            set_target_properties(${TEST_NAME} PROPERTIES
+                COMPILE_FLAGS "-fsanitize=undefined"
+                LINK_FLAGS    "-fsanitize=undefined")
+        endif()
+    endif()
+
     add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME} WORKING_DIRECTORY ${PROJECT_BINARY_DIR})
 
     # Set the PATH to be able to find Boost DLL

tests/test_error_detection.cpp

@@ -80,10 +80,14 @@ BOOST_AUTO_TEST_CASE(test_detect_conflicting_value)
 
 BOOST_AUTO_TEST_CASE(test_detect_inhomogeneous_array)
 {
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("heterogeneous array will be allowed in the next release");
+#else
     std::istringstream stream(std::string(
             "a = [1, 1.0]\n"
             ));
     BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_detect_appending_array_of_table)

tests/test_extended_conversions.cpp

@@ -33,6 +33,29 @@ struct bar
         return toml::table{{"a", this->a}, {"b", this->b}};
     }
 };
+
+struct baz
+{
+    int a;
+    std::string b;
+};
+struct qux
+{
+    int a;
+    std::string b;
+};
+
+struct foobar
+{
+    foobar() = default; // later we use std::vector<foobar>, default ctor is required.
+
+    // via constructor
+    explicit foobar(const toml::value& v)
+        : a(toml::find<int>(v, "a")), b(toml::find<std::string>(v, "b"))
+    {}
+    int a;
+    std::string b;
+};
 } // extlib
 
 namespace toml
@@ -54,6 +77,24 @@ struct into<extlib::foo>
         return toml::table{{"a", f.a}, {"b", f.b}};
     }
 };
+
+template<>
+struct from<extlib::baz>
+{
+    static extlib::baz from_toml(const toml::value& v)
+    {
+        return extlib::baz{toml::find<int>(v, "a"), toml::find<std::string>(v, "b")};
+    }
+};
+
+template<>
+struct into<extlib::qux>
+{
+    static toml::table into_toml(const extlib::qux& f)
+    {
+        return toml::table{{"a", f.a}, {"b", f.b}};
+    }
+};
 } // toml
 
 // ---------------------------------------------------------------------------
@@ -83,6 +124,29 @@ struct bar
         return toml::table{{"a", this->a}, {"b", this->b}};
     }
 };
+struct baz
+{
+    int a;
+    std::string b;
+};
+struct qux
+{
+    int a;
+    std::string b;
+};
+
+struct foobar
+{
+    foobar() = default; // later we use std::vector<foobar>, default ctor is required.
+
+    template<typename C, template<typename ...> class M, template<typename ...> class A>
+    explicit foobar(const toml::basic_value<C, M, A>& v)
+        : a(toml::find<int>(v, "a")), b(toml::find<std::string>(v, "b"))
+    {}
+    int a;
+    std::string b;
+};
+
 } // extlib2
 
 namespace toml
@@ -105,6 +169,28 @@ struct into<extlib2::foo>
         return toml::table{{"a", f.a}, {"b", f.b}};
     }
 };
+
+template<>
+struct from<extlib2::baz>
+{
+    template<typename C, template<typename ...> class M, template<typename ...> class A>
+    static extlib2::baz from_toml(const toml::basic_value<C, M, A>& v)
+    {
+        return extlib2::baz{toml::find<int>(v, "a"), toml::find<std::string>(v, "b")};
+    }
+};
+
+template<>
+struct into<extlib2::qux>
+{
+    static toml::basic_value<toml::preserve_comments, std::map>
+    into_toml(const extlib2::qux& f)
+    {
+        return toml::basic_value<toml::preserve_comments, std::map>{
+            {"a", f.a}, {"b", f.b}
+        };
+    }
+};
 } // toml
 
 // ---------------------------------------------------------------------------
@@ -188,6 +274,62 @@ BOOST_AUTO_TEST_CASE(test_conversion_by_specialization)
     }
 }
 
+BOOST_AUTO_TEST_CASE(test_conversion_one_way)
+{
+    {
+        const toml::value v{{"a", 42}, {"b", "baz"}};
+
+        const auto baz = toml::get<extlib::baz>(v);
+        BOOST_TEST(baz.a == 42);
+        BOOST_TEST(baz.b == "baz");
+    }
+    {
+        const extlib::qux q{42, "qux"};
+        const toml::value v(q);
+
+        BOOST_TEST(toml::find<int>(v, "a")         == 42);
+        BOOST_TEST(toml::find<std::string>(v, "b") == "qux");
+    }
+
+    {
+        const toml::basic_value<toml::discard_comments, std::map> v{
+            {"a", 42}, {"b", "baz"}
+        };
+
+        const auto baz = toml::get<extlib2::baz>(v);
+        BOOST_TEST(baz.a == 42);
+        BOOST_TEST(baz.b == "baz");
+    }
+    {
+        const extlib::qux q{42, "qux"};
+        const toml::basic_value<toml::preserve_comments, std::map> v(q);
+
+        BOOST_TEST(toml::find<int>(v, "a")         == 42);
+        BOOST_TEST(toml::find<std::string>(v, "b") == "qux");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_conversion_via_constructor)
+{
+    {
+        const toml::value v{{"a", 42}, {"b", "foobar"}};
+
+        const auto foobar = toml::get<extlib::foobar>(v);
+        BOOST_TEST(foobar.a == 42);
+        BOOST_TEST(foobar.b == "foobar");
+    }
+
+    {
+        const toml::basic_value<toml::discard_comments, std::map> v{
+            {"a", 42}, {"b", "foobar"}
+        };
+
+        const auto foobar = toml::get<extlib2::foobar>(v);
+        BOOST_TEST(foobar.a == 42);
+        BOOST_TEST(foobar.b == "foobar");
+    }
+}
+
 BOOST_AUTO_TEST_CASE(test_recursive_conversion)
 {
     {
@@ -288,5 +430,63 @@ BOOST_AUTO_TEST_CASE(test_recursive_conversion)
         BOOST_TEST(bars.at(2).b == "quux");
         BOOST_TEST(bars.at(3).b == "foobar");
     }
+
+    // via constructor
+    {
+        const toml::value v{
+                toml::table{{"a", 42}, {"b", "baz"}},
+                toml::table{{"a", 43}, {"b", "qux"}},
+                toml::table{{"a", 44}, {"b", "quux"}},
+                toml::table{{"a", 45}, {"b", "foobar"}}
+            };
+
+        {
+            const auto foobars = toml::get<std::vector<extlib::foobar>>(v);
+            BOOST_TEST(foobars.size()  == 4ul);
+            BOOST_TEST(foobars.at(0).a == 42);
+            BOOST_TEST(foobars.at(1).a == 43);
+            BOOST_TEST(foobars.at(2).a == 44);
+            BOOST_TEST(foobars.at(3).a == 45);
+
+            BOOST_TEST(foobars.at(0).b == "baz");
+            BOOST_TEST(foobars.at(1).b == "qux");
+            BOOST_TEST(foobars.at(2).b == "quux");
+            BOOST_TEST(foobars.at(3).b == "foobar");
+        }
+        {
+            const auto foobars = toml::get<std::vector<extlib2::foobar>>(v);
+            BOOST_TEST(foobars.size()  == 4ul);
+            BOOST_TEST(foobars.at(0).a == 42);
+            BOOST_TEST(foobars.at(1).a == 43);
+            BOOST_TEST(foobars.at(2).a == 44);
+            BOOST_TEST(foobars.at(3).a == 45);
+
+            BOOST_TEST(foobars.at(0).b == "baz");
+            BOOST_TEST(foobars.at(1).b == "qux");
+            BOOST_TEST(foobars.at(2).b == "quux");
+            BOOST_TEST(foobars.at(3).b == "foobar");
+        }
+    }
+    {
+        const toml::basic_value<toml::discard_comments, std::map, std::deque>
+            v{
+                toml::table{{"a", 42}, {"b", "baz"}},
+                toml::table{{"a", 43}, {"b", "qux"}},
+                toml::table{{"a", 44}, {"b", "quux"}},
+                toml::table{{"a", 45}, {"b", "foobar"}}
+            };
+
+        const auto foobars = toml::get<std::vector<extlib2::foobar>>(v);
+        BOOST_TEST(foobars.size()  == 4ul);
+        BOOST_TEST(foobars.at(0).a == 42);
+        BOOST_TEST(foobars.at(1).a == 43);
+        BOOST_TEST(foobars.at(2).a == 44);
+        BOOST_TEST(foobars.at(3).a == 45);
+
+        BOOST_TEST(foobars.at(0).b == "baz");
+        BOOST_TEST(foobars.at(1).b == "qux");
+        BOOST_TEST(foobars.at(2).b == "quux");
+        BOOST_TEST(foobars.at(3).b == "foobar");
+    }
 }
 

tests/test_find.cpp

@@ -27,6 +27,32 @@ using test_value_types = std::tuple<
 
 BOOST_AUTO_TEST_CASE(test_find_throws)
 {
+    // -----------------------------------------------------------------------
+    // const-reference version
+    {
+        // value is not a table
+        const toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, "key"), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        const toml::value v{{"key", 42}};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, "key"), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        const toml::value v{{"key", 42}};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(v, "different_key"),
+                          std::out_of_range);
+    }
+    {
+        // the positive control.
+        const toml::value v{{"key", 42}};
+        BOOST_TEST(42 == toml::find<int>(v, "key"));
+    }
+
+    // -----------------------------------------------------------------------
+    // reference version
     {
         // value is not a table
         toml::value v(true);
@@ -48,6 +74,103 @@ BOOST_AUTO_TEST_CASE(test_find_throws)
         toml::value v{{"key", 42}};
         BOOST_TEST(42 == toml::find<int>(v, "key"));
     }
+
+    // -----------------------------------------------------------------------
+    // move version
+
+    {
+        // value is not a table
+        toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(std::move(v), "key"), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        toml::value v{{"key", 42}};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(std::move(v), "key"), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        toml::value v{{"key", 42}};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(std::move(v), "different_key"),
+                          std::out_of_range);
+    }
+    {
+        // the positive control.
+        toml::value v{{"key", 42}};
+        BOOST_TEST(42 == toml::find<int>(std::move(v), "key"));
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_find_array_throws)
+{
+    // -----------------------------------------------------------------------
+    // const-reference version
+    {
+        // value is not an array
+        const toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        const toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        const toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(v, 6), std::out_of_range);
+    }
+    {
+        // the positive control.
+        const toml::value v{1, 2, 3, 4, 5};
+        BOOST_TEST(3 == toml::find<int>(v, 2));
+    }
+
+    // -----------------------------------------------------------------------
+    // non-const reference version
+    {
+        // value is not an array
+        toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(v, 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(v, 6), std::out_of_range);
+    }
+    {
+        // the positive control.
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_TEST(3 == toml::find<int>(v, 2));
+    }
+
+    // -----------------------------------------------------------------------
+    // move version
+    {
+        // value is not an array
+        toml::value v(true);
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(std::move(v), 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not the expected type
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::boolean>(std::move(v), 0), toml::type_error);
+    }
+    {
+        // the value corresponding to the key is not found
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_CHECK_THROW(toml::find<toml::integer>(std::move(v), 6), std::out_of_range);
+    }
+    {
+        // the positive control.
+        toml::value v{1, 2, 3, 4, 5};
+        BOOST_TEST(3 == toml::find<int>(std::move(v), 2));
+    }
 }
 
 BOOST_AUTO_TEST_CASE(test_find_recursive)
@@ -74,6 +197,77 @@ BOOST_AUTO_TEST_CASE(test_find_recursive)
         auto& num2 = toml::find<toml::integer>(v, a, b, c, d);
         num2 = 42;
         BOOST_TEST(42 == toml::find<int>(v, a, b, c, d));
+
+        auto num3 = toml::find<toml::integer>(v, a, "b", c, "d");
+        BOOST_TEST(42 == num3);
+
+        auto num4 = toml::find<toml::integer>(std::move(v), a, b, c, d);
+        BOOST_TEST(42 == num4);
+    }
+    // recursively search arrays
+    {
+        toml::value v{
+            toml::array{"array", "of", "string"},
+            toml::array{toml::array{1, 2, 3}, toml::array{3.14, 2.71}}
+        };
+        BOOST_TEST("array"  == toml::find<std::string>(v, 0, 0));
+        BOOST_TEST("of"     == toml::find<std::string>(v, 0, 1));
+        BOOST_TEST("string" == toml::find<std::string>(v, 0, 2));
+
+        BOOST_TEST(1 == toml::find<int>(v, 1, 0, 0));
+        BOOST_TEST(2 == toml::find<int>(v, 1, 0, 1));
+        BOOST_TEST(3 == toml::find<int>(v, 1, 0, 2));
+
+        BOOST_TEST(3.14 == toml::find<double>(v, 1, 1, 0));
+        BOOST_TEST(2.71 == toml::find<double>(v, 1, 1, 1));
+
+        // reference that can be used to modify the content
+        auto& num = toml::find<toml::integer>(v, 1, 0, 2);
+        num = 42;
+        BOOST_TEST( 1 == toml::find<int>(v, 1, 0, 0));
+        BOOST_TEST( 2 == toml::find<int>(v, 1, 0, 1));
+        BOOST_TEST(42 == toml::find<int>(v, 1, 0, 2));
+
+        // move value
+        auto num2 = toml::find<toml::integer>(std::move(v), 1, 0, 2);
+        BOOST_TEST(42 == num2);
+    }
+    // recursively search mixtures
+    {
+        toml::value v = toml::table{{"array", toml::array{
+                toml::array{1,   2,   3},
+                toml::array{
+                    toml::table{{"foo", "bar"}, {"baz", "qux"}},
+                    toml::table{{"pi",   3.14}, {"e",    2.71}}
+                }}
+            }};
+
+        BOOST_TEST(1 == toml::find<int>(v, "array", 0, 0));
+        BOOST_TEST(2 == toml::find<int>(v, "array", 0, 1));
+        BOOST_TEST(3 == toml::find<int>(v, "array", 0, 2));
+
+        BOOST_TEST("bar" == toml::find<std::string>(v, "array", 1, 0, "foo"));
+        BOOST_TEST("qux" == toml::find<std::string>(v, "array", 1, 0, "baz"));
+
+        BOOST_TEST(3.14 == toml::find<double>(v, "array", 1, 1, "pi"));
+        BOOST_TEST(2.71 == toml::find<double>(v, "array", 1, 1, "e"));
+
+        const std::string ar("array");
+        const auto ar_c = "array";
+
+        const std::string pi("pi");
+        const auto pi_c = "pi";
+
+        BOOST_TEST(3.14 == toml::find<double>(v, ar, 1, 1, "pi"));
+        BOOST_TEST(3.14 == toml::find<double>(v, ar, 1, 1, pi));
+        BOOST_TEST(3.14 == toml::find<double>(v, ar, 1, 1, pi_c));
+
+        BOOST_TEST(3.14 == toml::find<double>(v, ar_c, 1, 1, "pi"));
+        BOOST_TEST(3.14 == toml::find<double>(v, ar_c, 1, 1, pi));
+        BOOST_TEST(3.14 == toml::find<double>(v, ar_c, 1, 1, pi_c));
+
+        BOOST_TEST(3.14 == toml::find<double>(v, "array", 1, 1, pi));
+        BOOST_TEST(3.14 == toml::find<double>(v, "array", 1, 1, pi_c));
     }
 }
 
@@ -85,6 +279,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
 
         toml::find<toml::boolean>(v, "key") = false;
         BOOST_TEST(false == toml::find<toml::boolean>(v, "key"));
+
+        const auto moved = toml::find<toml::boolean>(std::move(v), "key");
+        BOOST_TEST(false == moved);
     }
     {
         value_type v{{"key", 42}};
@@ -92,6 +289,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
 
         toml::find<toml::integer>(v, "key") = 54;
         BOOST_TEST(toml::integer(54) == toml::find<toml::integer>(v, "key"));
+
+        const auto moved = toml::find<toml::integer>(std::move(v), "key");
+        BOOST_TEST(toml::integer(54) == moved);
     }
     {
         value_type v{{"key", 3.14}};
@@ -99,6 +299,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
 
         toml::find<toml::floating>(v, "key") = 2.71;
         BOOST_TEST(toml::floating(2.71) == toml::find<toml::floating>(v, "key"));
+
+        const auto moved = toml::find<toml::floating>(std::move(v), "key");
+        BOOST_TEST(toml::floating(2.71) == moved);
     }
     {
         value_type v{{"key", "foo"}};
@@ -108,6 +311,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
         toml::find<toml::string>(v, "key").str += "bar";
         BOOST_TEST(toml::string("foobar", toml::string_t::basic) ==
                           toml::find<toml::string>(v, "key"));
+
+        const auto moved = toml::find<toml::string>(std::move(v), "key");
+        BOOST_TEST(toml::string("foobar", toml::string_t::basic) == moved);
     }
     {
         value_type v{{"key", value_type("foo", toml::string_t::literal)}};
@@ -117,6 +323,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
         toml::find<toml::string>(v, "key").str += "bar";
         BOOST_TEST(toml::string("foobar", toml::string_t::literal) ==
                           toml::find<toml::string>(v, "key"));
+
+        const auto moved = toml::find<toml::string>(std::move(v), "key");
+        BOOST_TEST(toml::string("foobar", toml::string_t::literal) == moved);
     }
     {
         toml::local_date d(2018, toml::month_t::Apr, 22);
@@ -126,6 +335,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
         toml::find<toml::local_date>(v, "key").year = 2017;
         d.year = 2017;
         BOOST_CHECK(d == toml::find<toml::local_date>(v, "key"));
+
+        const auto moved = toml::find<toml::local_date>(std::move(v), "key");
+        BOOST_CHECK(d == moved);
     }
     {
         toml::local_time t(12, 30, 45);
@@ -135,6 +347,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
         toml::find<toml::local_time>(v, "key").hour = 9;
         t.hour = 9;
         BOOST_CHECK(t == toml::find<toml::local_time>(v, "key"));
+
+        const auto moved = toml::find<toml::local_time>(std::move(v), "key");
+        BOOST_CHECK(t == moved);
     }
     {
         toml::local_datetime dt(toml::local_date(2018, toml::month_t::Apr, 22),
@@ -145,6 +360,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
         toml::find<toml::local_datetime>(v, "key").date.year = 2017;
         dt.date.year = 2017;
         BOOST_CHECK(dt == toml::find<toml::local_datetime>(v, "key"));
+
+        const auto moved = toml::find<toml::local_datetime>(std::move(v), "key");
+        BOOST_CHECK(dt == moved);
     }
     {
         toml::offset_datetime dt(toml::local_datetime(
@@ -156,6 +374,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
         toml::find<toml::offset_datetime>(v, "key").date.year = 2017;
         dt.date.year = 2017;
         BOOST_CHECK(dt == toml::find<toml::offset_datetime>(v, "key"));
+
+        const auto moved = toml::find<toml::offset_datetime>(std::move(v), "key");
+        BOOST_CHECK(dt == moved);
     }
     {
         typename value_type::array_type vec;
@@ -171,6 +392,10 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
 
         const bool result2 = (vec == toml::find<typename value_type::array_type>(v, "key"));
         BOOST_CHECK(result2);
+
+        const auto moved = toml::find<typename value_type::array_type>(std::move(v), "key");
+        const bool result3 = (vec == moved);
+        BOOST_CHECK(result3);
     }
     {
         typename value_type::table_type tab;
@@ -184,6 +409,10 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
         tab["key3"] = value_type(123);
         const bool result2 = (tab == toml::find<typename value_type::table_type>(v, "key"));
         BOOST_CHECK(result2);
+
+        const auto moved = toml::find<typename value_type::table_type>(std::move(v), "key");
+        const bool result3 = (tab == moved);
+        BOOST_CHECK(result3);
     }
     {
         value_type v1(42);
@@ -193,6 +422,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_exact, value_type, test_value_types)
         value_type v2(54);
         toml::find(v, "key") = v2;
         BOOST_CHECK(v2 == toml::find(v, "key"));
+
+        const auto moved = toml::find(std::move(v), "key");
+        BOOST_CHECK(v2 == moved);
     }
 }
 
@@ -209,6 +441,7 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_integer_type, value_type, test_value_typ
         BOOST_TEST(std::uint64_t(42) == toml::find<std::uint64_t>(v, "key"));
         BOOST_TEST(std::int16_t(42)  == toml::find<std::int16_t >(v, "key"));
         BOOST_TEST(std::uint16_t(42) == toml::find<std::uint16_t>(v, "key"));
+        BOOST_TEST(std::uint16_t(42) == toml::find<std::uint16_t>(std::move(v), "key"));
     }
 }
 
@@ -216,9 +449,11 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_floating_type, value_type, test_value_ty
 {
     {
         value_type v{{"key", 3.14}};
-        BOOST_TEST(static_cast<float      >(3.14) == toml::find<float      >(v, "key"));
+        const double ref(3.14);
-        BOOST_TEST(static_cast<double     >(3.14) == toml::find<double     >(v, "key"));
+        BOOST_TEST(static_cast<float      >(ref) == toml::find<float      >(v, "key"));
-        BOOST_TEST(static_cast<long double>(3.14) == toml::find<long double>(v, "key"));
+        BOOST_TEST(                         ref  == toml::find<double     >(v, "key"));
+        BOOST_TEST(static_cast<long double>(ref) == toml::find<long double>(v, "key"));
+        BOOST_TEST(static_cast<float      >(ref) == toml::find<float      >(std::move(v), "key"));
     }
 }
 
@@ -236,6 +471,11 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_string_type, value_type, test_value_type
         toml::find<std::string>(v, "key") += "bar";
         BOOST_TEST("foobar" == toml::find<std::string>(v, "key"));
     }
+    {
+        value_type v{{"key", toml::string("foo", toml::string_t::literal)}};
+        const auto moved = toml::find<std::string>(std::move(v), "key");
+        BOOST_TEST("foo" == moved);
+    }
 
 #if __cplusplus >= 201703L
     {
@@ -274,14 +514,14 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_array, value_type, test_value_types
     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(42 == ary.at(0));
-    BOOST_TEST(static_cast<int>(54) == ary.at(1));
+    BOOST_TEST(54 == ary.at(1));
-    BOOST_TEST(static_cast<int>(69) == ary.at(2));
+    BOOST_TEST(69 == ary.at(2));
-    BOOST_TEST(static_cast<int>(72) == ary.at(3));
+    BOOST_TEST(72 == ary.at(3));
 
     std::tuple<int, short, unsigned, long> tpl =
         toml::find<std::tuple<int, short, unsigned, long>>(v, "key");
-    BOOST_TEST(static_cast<int     >(42) == std::get<0>(tpl));
+    BOOST_TEST(                      42  == std::get<0>(tpl));
     BOOST_TEST(static_cast<short   >(54) == std::get<1>(tpl));
     BOOST_TEST(static_cast<unsigned>(69) == std::get<2>(tpl));
     BOOST_TEST(static_cast<long    >(72) == std::get<3>(tpl));
@@ -292,6 +532,53 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_array, value_type, test_value_types
     BOOST_TEST(2.71 == pr.second);
 }
 
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_move_toml_array, value_type, test_value_types)
+{
+    value_type v1{{"key", {42, 54, 69, 72}}};
+    value_type v2{{"key", {42, 54, 69, 72}}};
+    value_type v3{{"key", {42, 54, 69, 72}}};
+    value_type v4{{"key", {42, 54, 69, 72}}};
+    value_type v5{{"key", {42, 54, 69, 72}}};
+
+    const std::vector<int>         vec = toml::find<std::vector<int>>(std::move(v1), "key");
+    const std::list<short>         lst = toml::find<std::list<short>>(std::move(v2), "key");
+    const std::deque<std::int64_t> deq = toml::find<std::deque<std::int64_t>>(std::move(v3), "key");
+
+    BOOST_TEST(42 == vec.at(0));
+    BOOST_TEST(54 == vec.at(1));
+    BOOST_TEST(69 == vec.at(2));
+    BOOST_TEST(72 == vec.at(3));
+
+    std::list<short>::const_iterator iter = lst.begin();
+    BOOST_TEST(static_cast<short>(42) == *(iter++));
+    BOOST_TEST(static_cast<short>(54) == *(iter++));
+    BOOST_TEST(static_cast<short>(69) == *(iter++));
+    BOOST_TEST(static_cast<short>(72) == *(iter++));
+
+    BOOST_TEST(static_cast<std::int64_t>(42) == deq.at(0));
+    BOOST_TEST(static_cast<std::int64_t>(54) == deq.at(1));
+    BOOST_TEST(static_cast<std::int64_t>(69) == deq.at(2));
+    BOOST_TEST(static_cast<std::int64_t>(72) == deq.at(3));
+
+    std::array<int, 4> ary = toml::find<std::array<int, 4>>(std::move(v4), "key");
+    BOOST_TEST(42 == ary.at(0));
+    BOOST_TEST(54 == ary.at(1));
+    BOOST_TEST(69 == ary.at(2));
+    BOOST_TEST(72 == ary.at(3));
+
+    std::tuple<int, short, unsigned, long> tpl =
+        toml::find<std::tuple<int, short, unsigned, long>>(std::move(v5), "key");
+    BOOST_TEST(                      42  == std::get<0>(tpl));
+    BOOST_TEST(static_cast<short   >(54) == std::get<1>(tpl));
+    BOOST_TEST(static_cast<unsigned>(69) == std::get<2>(tpl));
+    BOOST_TEST(static_cast<long    >(72) == std::get<3>(tpl));
+
+    value_type p{{"key", {3.14, 2.71}}};
+    std::pair<double, double> pr = toml::find<std::pair<double, double> >(std::move(p), "key");
+    BOOST_TEST(3.14 == pr.first);
+    BOOST_TEST(2.71 == pr.second);
+}
+
 BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_array_of_array, value_type, test_value_types)
 {
     value_type v1{42, 54, 69, 72};
@@ -323,8 +610,42 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_array_of_array, value_type, test_va
     BOOST_TEST(std::get<1>(t).at(2) == "baz");
 }
 
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_move_toml_array_of_array, value_type, test_value_types)
+{
+    value_type a1{42, 54, 69, 72};
+    value_type a2{"foo", "bar", "baz"};
+    value_type v1{{"key", {a1, a2}}};
+    value_type v2{{"key", {a1, a2}}};
+
+    std::pair<std::vector<int>, std::vector<std::string>> p =
+        toml::find<std::pair<std::vector<int>, std::vector<std::string>>>(std::move(v1), "key");
+
+    BOOST_TEST(p.first.at(0) == 42);
+    BOOST_TEST(p.first.at(1) == 54);
+    BOOST_TEST(p.first.at(2) == 69);
+    BOOST_TEST(p.first.at(3) == 72);
+
+    BOOST_TEST(p.second.at(0) == "foo");
+    BOOST_TEST(p.second.at(1) == "bar");
+    BOOST_TEST(p.second.at(2) == "baz");
+
+    std::tuple<std::vector<int>, std::vector<std::string>> t =
+        toml::find<std::tuple<std::vector<int>, std::vector<std::string>>>(std::move(v2), "key");
+
+    BOOST_TEST(std::get<0>(t).at(0) == 42);
+    BOOST_TEST(std::get<0>(t).at(1) == 54);
+    BOOST_TEST(std::get<0>(t).at(2) == 69);
+    BOOST_TEST(std::get<0>(t).at(3) == 72);
+
+    BOOST_TEST(std::get<1>(t).at(0) == "foo");
+    BOOST_TEST(std::get<1>(t).at(1) == "bar");
+    BOOST_TEST(std::get<1>(t).at(2) == "baz");
+}
+
+
 BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_table, value_type, test_value_types)
 {
+    {
         value_type v1{{"key", {
                 {"key1", 1}, {"key2", 2}, {"key3", 3}, {"key4", 4}
             }}};
@@ -333,10 +654,22 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_table, value_type, test_value_types
         BOOST_TEST(v.at("key2") == 2);
         BOOST_TEST(v.at("key3") == 3);
         BOOST_TEST(v.at("key4") == 4);
+    }
+    {
+        value_type v1{{"key", {
+                {"key1", 1}, {"key2", 2}, {"key3", 3}, {"key4", 4}
+            }}};
+        const auto v = toml::find<std::map<std::string, int>>(std::move(v1), "key");
+        BOOST_TEST(v.at("key1") == 1);
+        BOOST_TEST(v.at("key2") == 2);
+        BOOST_TEST(v.at("key3") == 3);
+        BOOST_TEST(v.at("key4") == 4);
+    }
 }
 
 BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_local_date, value_type, test_value_types)
 {
+    {
         value_type v1{{"key", toml::local_date{2018, toml::month_t::Apr, 1}}};
         const auto date = std::chrono::system_clock::to_time_t(
                 toml::find<std::chrono::system_clock::time_point>(v1, "key"));
@@ -351,18 +684,44 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_local_date, value_type, test_value_
         t.tm_isdst = -1;
         const auto c = std::mktime(&t);
         BOOST_TEST(c == date);
+    }
+    {
+        value_type v1{{"key", toml::local_date{2018, toml::month_t::Apr, 1}}};
+        const auto date = std::chrono::system_clock::to_time_t(
+                toml::find<std::chrono::system_clock::time_point>(std::move(v1), "key"));
+
+        std::tm t;
+        t.tm_year = 2018 - 1900;
+        t.tm_mon  = 4    - 1;
+        t.tm_mday = 1;
+        t.tm_hour = 0;
+        t.tm_min  = 0;
+        t.tm_sec  = 0;
+        t.tm_isdst = -1;
+        const auto c = std::mktime(&t);
+        BOOST_TEST(c == date);
+    }
 }
 
 BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_local_time, value_type, test_value_types)
 {
+    {
         value_type v1{{"key", toml::local_time{12, 30, 45}}};
         const auto time = toml::find<std::chrono::seconds>(v1, "key");
         BOOST_CHECK(time == std::chrono::hours(12) +
                             std::chrono::minutes(30) + std::chrono::seconds(45));
+    }
+    {
+        value_type v1{{"key", toml::local_time{12, 30, 45}}};
+        const auto time = toml::find<std::chrono::seconds>(std::move(v1), "key");
+        BOOST_CHECK(time == std::chrono::hours(12) +
+                            std::chrono::minutes(30) + std::chrono::seconds(45));
+    }
 }
 
 BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_local_datetime, value_type, test_value_types)
 {
+    {
         value_type v1{{"key", toml::local_datetime(
                     toml::local_date{2018, toml::month_t::Apr, 1},
                     toml::local_time{12, 30, 45})}};
@@ -379,6 +738,25 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_toml_local_datetime, value_type, test_va
         t.tm_isdst = -1;
         const auto c = std::mktime(&t);
         BOOST_TEST(c == date);
+    }
+    {
+        value_type v1{{"key", toml::local_datetime(
+                    toml::local_date{2018, toml::month_t::Apr, 1},
+                    toml::local_time{12, 30, 45})}};
+
+        const auto date = std::chrono::system_clock::to_time_t(
+                toml::find<std::chrono::system_clock::time_point>(std::move(v1), "key"));
+        std::tm t;
+        t.tm_year = 2018 - 1900;
+        t.tm_mon  = 4    - 1;
+        t.tm_mday = 1;
+        t.tm_hour = 12;
+        t.tm_min  = 30;
+        t.tm_sec  = 45;
+        t.tm_isdst = -1;
+        const auto c = std::mktime(&t);
+        BOOST_TEST(c == date);
+    }
 }
 
 BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_offset_datetime, value_type, test_value_types)
@@ -428,5 +806,28 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_offset_datetime, value_type, test_va
         BOOST_TEST(tm.tm_min ==           30);
         BOOST_TEST(tm.tm_sec ==            0);
     }
+
+    {
+        value_type v1{{"key", toml::offset_datetime(
+                    toml::local_date{2018, toml::month_t::Apr, 1},
+                    toml::local_time{12, 30, 0},
+                    toml::time_offset{-8, 0})}};
+        //    2018-04-01T12:30:00-08:00
+        // == 2018-04-01T20:30:00Z
+
+        const auto date = toml::find<std::chrono::system_clock::time_point>(std::move(v1), "key");
+        const auto timet = std::chrono::system_clock::to_time_t(date);
+
+        // get time_t as gmtime (2018-04-01T03:30:00Z)
+        const auto tmp = std::gmtime(std::addressof(timet)); // XXX not threadsafe!
+        BOOST_CHECK(tmp);
+        const auto tm = *tmp;
+        BOOST_TEST(tm.tm_year + 1900 == 2018);
+        BOOST_TEST(tm.tm_mon  + 1 ==       4);
+        BOOST_TEST(tm.tm_mday ==           1);
+        BOOST_TEST(tm.tm_hour ==          20);
+        BOOST_TEST(tm.tm_min ==           30);
+        BOOST_TEST(tm.tm_sec ==            0);
+    }
 }
 

tests/test_find_or.cpp

@@ -121,6 +121,55 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_exact, value_type, test_value_types)
 }
 #undef TOML11_TEST_FIND_OR_EXACT
 
+#define TOML11_TEST_FIND_OR_MOVE(toml_type, init_expr, opt_expr)   \
+    {                                                              \
+        using namespace test;                                      \
+        const toml::toml_type init init_expr ;                     \
+        toml::toml_type opt  opt_expr ;                            \
+        value_type v{{"key", init}};                               \
+        BOOST_TEST(init != opt);                                   \
+        const auto moved = toml::find_or(std::move(v), "key", std::move(opt));\
+        BOOST_TEST(init == moved);                                 \
+    }                                                              \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_move, value_type, test_value_types)
+{
+    TOML11_TEST_FIND_OR_MOVE(boolean,         ( true), (false))
+    TOML11_TEST_FIND_OR_MOVE(integer,         (   42), (   54))
+    TOML11_TEST_FIND_OR_MOVE(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_FIND_OR_MOVE(string,          ("foo"), ("bar"))
+    TOML11_TEST_FIND_OR_MOVE(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_FIND_OR_MOVE(local_date,      (2019, toml::month_t::Apr, 1),
+                                              (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_FIND_OR_MOVE(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_FIND_OR_MOVE(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        typename value_type::array_type init{1,2,3,4,5};
+        typename value_type::array_type opt {6,7,8,9,10};
+        value_type v{{"key", init}};
+        BOOST_TEST(init != opt);
+        const auto moved = toml::find_or(std::move(v), "key", std::move(opt));
+        BOOST_TEST(init == moved);
+    }
+    {
+        typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        typename value_type::table_type opt {{"key1", 54}, {"key2", "bar"}};
+        value_type v{{"key", init}};
+        BOOST_TEST(init != opt);
+        const auto moved = toml::find_or(std::move(v), "key", std::move(opt));
+        BOOST_TEST(init == moved);
+    }
+}
+#undef TOML11_TEST_FIND_OR_MOVE
+
+
 #define TOML11_TEST_FIND_OR_MODIFY(toml_type, init_expr, opt_expr)\
     {                                                             \
         using namespace test;                                     \
@@ -304,10 +353,20 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_find_or_fallback, value_type, test_value_type
 BOOST_AUTO_TEST_CASE(test_find_or_integer)
 {
     {
-        toml::value v = toml::table{{"num", 42}};
+        toml::value v{{"num", 42}};
         BOOST_TEST(42u == toml::find_or(v, "num", 0u));
         BOOST_TEST(0u ==  toml::find_or(v, "foo", 0u));
     }
+    {
+        toml::value v{{"num", 42}};
+        const auto moved = toml::find_or(std::move(v), "num", 0u);
+        BOOST_TEST(42u == moved);
+    }
+    {
+        toml::value v{{"num", 42}};
+        const auto moved = toml::find_or(std::move(v), "foo", 0u);
+        BOOST_TEST(0u ==  moved);
+    }
 }
 
 BOOST_AUTO_TEST_CASE(test_find_or_floating)
@@ -316,7 +375,17 @@ 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));
+        const double ref(3.14);
+        BOOST_TEST(static_cast<float>(ref) == toml::find_or(v2, "key", 2.71f));
+    }
+    {
+        toml::value v1{{"key", 42}};
+        toml::value v2{{"key", 3.14}};
+        const auto moved1 = toml::find_or(std::move(v1), "key", 2.71f);
+        const auto moved2 = toml::find_or(std::move(v2), "key", 2.71f);
+        BOOST_TEST(2.71f == moved1);
+        const double ref(3.14);
+        BOOST_TEST(static_cast<float>(ref) == moved2);
     }
 }
 
@@ -345,6 +414,32 @@ BOOST_AUTO_TEST_CASE(test_find_or_string)
         s1 = "bazqux"; // restoring moved value
         BOOST_TEST("bazqux" == toml::find_or(std::move(v2), "key", std::move(s1)));
     }
+    {
+        toml::value v1 = toml::table{{"key", "foobar"}};
+        toml::value v2 = toml::table{{"key", 42}};
+
+        std::string s1("bazqux");
+
+        const auto moved1 = toml::find_or(std::move(v1), "key", s1);
+        const auto moved2 = toml::find_or(std::move(v2), "key", s1);
+
+        BOOST_TEST("foobar" == moved1);
+        BOOST_TEST("bazqux" == moved2);
+    }
+    {
+        toml::value v1 = toml::table{{"key", "foobar"}};
+        toml::value v2 = toml::table{{"key", 42}};
+
+        std::string s1("bazqux");
+        std::string s2("bazqux");
+
+        const auto moved1 = toml::find_or(std::move(v1), "key", std::move(s1));
+        const auto moved2 = toml::find_or(std::move(v2), "key", std::move(s2));
+
+        BOOST_TEST("foobar" == moved1);
+        BOOST_TEST("bazqux" == moved2);
+    }
+
     // string literal
     {
         toml::value v1 = toml::table{{"key", "foobar"}};
@@ -357,4 +452,90 @@ BOOST_AUTO_TEST_CASE(test_find_or_string)
         BOOST_TEST("foobar" == toml::find_or(v1, "key", lit));
         BOOST_TEST("bazqux" == toml::find_or(v2, "key", lit));
     }
+    {
+        toml::value v1 = toml::table{{"key", "foobar"}};
+        toml::value v2 = toml::table{{"key",42}};
+
+        const auto moved1 = toml::find_or(std::move(v1), "key", "bazqux");
+        const auto moved2 = toml::find_or(std::move(v2), "key", "bazqux");
+
+        BOOST_TEST("foobar" == moved1);
+        BOOST_TEST("bazqux" == moved2);
+    }
+    {
+        toml::value v1 = toml::table{{"key", "foobar"}};
+        toml::value v2 = toml::table{{"key",42}};
+
+        const char* lit = "bazqux";
+        const auto moved1 = toml::find_or(std::move(v1), "key", lit);
+        const auto moved2 = toml::find_or(std::move(v2), "key", lit);
+
+        BOOST_TEST("foobar" == moved1);
+        BOOST_TEST("bazqux" == moved2);
+    }
+
+}
+
+BOOST_AUTO_TEST_CASE(test_find_or_map)
+{
+    using map_type = std::map<std::string, std::string>;
+    {
+        const toml::value v1{
+            {"key", {{"key", "value"}}}
+        };
+
+        const auto key  = toml::find_or(v1, "key",  map_type{});
+        const auto key2 = toml::find_or(v1, "key2", map_type{});
+
+        BOOST_TEST(!key.empty());
+        BOOST_TEST(key2.empty());
+
+        BOOST_TEST(key.size()    == 1u);
+        BOOST_TEST(key.at("key") == "value");
+    }
+    {
+        toml::value v1{
+            {"key", {{"key", "value"}}}
+        };
+
+        const auto key  = toml::find_or<map_type>(v1, "key",  map_type{});
+        const auto key2 = toml::find_or<map_type>(v1, "key2", map_type{});
+
+        BOOST_TEST(!key.empty());
+        BOOST_TEST(key2.empty());
+
+        BOOST_TEST(key.size()    == 1u);
+        BOOST_TEST(key.at("key") == "value");
+    }
+
+    {
+        toml::value v1{
+            {"key", {{"key", "value"}}}
+        };
+        toml::value v2(v1);
+
+        const auto key  = toml::find_or(std::move(v1), "key",  map_type{});
+        const auto key2 = toml::find_or(std::move(v2), "key2", map_type{});
+
+        BOOST_TEST(!key.empty());
+        BOOST_TEST(key2.empty());
+
+        BOOST_TEST(key.size()    == 1u);
+        BOOST_TEST(key.at("key") == "value");
+    }
+    {
+        toml::value v1{
+            {"key", {{"key", "value"}}}
+        };
+        toml::value v2(v1);
+
+        const auto key  = toml::find_or<map_type>(std::move(v1), "key",  map_type{});
+        const auto key2 = toml::find_or<map_type>(std::move(v2), "key2", map_type{});
+
+        BOOST_TEST(!key.empty());
+        BOOST_TEST(key2.empty());
+
+        BOOST_TEST(key.size()    == 1u);
+        BOOST_TEST(key.at("key") == "value");
+    }
 }

tests/test_get.cpp

@@ -31,6 +31,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
 
         toml::get<toml::boolean>(v) = false;
         BOOST_TEST(false == toml::get<toml::boolean>(v));
+
+        toml::boolean x = toml::get<toml::boolean>(std::move(v));
+        BOOST_TEST(false == x);
     }
     {
         value_type v(42);
@@ -38,6 +41,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
 
         toml::get<toml::integer>(v) = 54;
         BOOST_TEST(toml::integer(54) == toml::get<toml::integer>(v));
+
+        toml::integer x = toml::get<toml::integer>(std::move(v));
+        BOOST_TEST(toml::integer(54) == x);
     }
     {
         value_type v(3.14);
@@ -45,6 +51,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
 
         toml::get<toml::floating>(v) = 2.71;
         BOOST_TEST(toml::floating(2.71) == toml::get<toml::floating>(v));
+
+        toml::floating x = toml::get<toml::floating>(std::move(v));
+        BOOST_TEST(toml::floating(2.71) == x);
     }
     {
         value_type v("foo");
@@ -54,6 +63,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
         toml::get<toml::string>(v).str += "bar";
         BOOST_TEST(toml::string("foobar", toml::string_t::basic) ==
                           toml::get<toml::string>(v));
+
+        toml::string x = toml::get<toml::string>(std::move(v));
+        BOOST_TEST(toml::string("foobar") == x);
     }
     {
         value_type v("foo", toml::string_t::literal);
@@ -63,6 +75,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
         toml::get<toml::string>(v).str += "bar";
         BOOST_TEST(toml::string("foobar", toml::string_t::literal) ==
                           toml::get<toml::string>(v));
+
+        toml::string x = toml::get<toml::string>(std::move(v));
+        BOOST_TEST(toml::string("foobar", toml::string_t::literal) == x);
     }
     {
         toml::local_date d(2018, toml::month_t::Apr, 22);
@@ -72,6 +87,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
         toml::get<toml::local_date>(v).year = 2017;
         d.year = 2017;
         BOOST_TEST(d == toml::get<toml::local_date>(v));
+
+        toml::local_date x = toml::get<toml::local_date>(std::move(v));
+        BOOST_TEST(d == x);
     }
     {
         toml::local_time t(12, 30, 45);
@@ -81,6 +99,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
         toml::get<toml::local_time>(v).hour = 9;
         t.hour = 9;
         BOOST_TEST(t == toml::get<toml::local_time>(v));
+
+        toml::local_time x = toml::get<toml::local_time>(std::move(v));
+        BOOST_TEST(t == x);
     }
     {
         toml::local_datetime dt(toml::local_date(2018, toml::month_t::Apr, 22),
@@ -91,6 +112,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
         toml::get<toml::local_datetime>(v).date.year = 2017;
         dt.date.year = 2017;
         BOOST_TEST(dt == toml::get<toml::local_datetime>(v));
+
+        toml::local_datetime x = toml::get<toml::local_datetime>(std::move(v));
+        BOOST_TEST(dt == x);
     }
     {
         toml::offset_datetime dt(toml::local_datetime(
@@ -102,6 +126,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
         toml::get<toml::offset_datetime>(v).date.year = 2017;
         dt.date.year = 2017;
         BOOST_TEST(dt == toml::get<toml::offset_datetime>(v));
+
+        toml::offset_datetime x = toml::get<toml::offset_datetime>(std::move(v));
+        BOOST_TEST(dt == x);
     }
     {
         using array_type = typename value_type::array_type;
@@ -114,6 +141,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
         toml::get<array_type>(v).push_back(value_type(123));
         vec.push_back(value_type(123));
         BOOST_TEST(vec == toml::get<array_type>(v));
+
+        array_type x = toml::get<array_type>(std::move(v));
+        BOOST_TEST(vec == x);
     }
     {
         using table_type = typename value_type::table_type;
@@ -126,6 +156,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
         toml::get<table_type>(v)["key3"] = value_type(123);
         tab["key3"] = value_type(123);
         BOOST_TEST(tab == toml::get<table_type>(v));
+
+        table_type x = toml::get<table_type>(std::move(v));
+        BOOST_TEST(tab == x);
     }
     {
         value_type v1(42);
@@ -134,6 +167,9 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_exact, value_type, test_value_types)
         value_type v2(54);
         toml::get<value_type>(v1) = v2;
         BOOST_TEST(v2 == toml::get<value_type>(v1));
+
+        value_type x = toml::get<value_type>(std::move(v1));
+        BOOST_TEST(v2 == x);
     }
 }
 
@@ -150,6 +186,8 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_integer_type, value_type, test_value_type
         BOOST_TEST(std::uint64_t(42) == toml::get<std::uint64_t>(v));
         BOOST_TEST(std::int16_t(42) ==  toml::get<std::int16_t >(v));
         BOOST_TEST(std::uint16_t(42) == toml::get<std::uint16_t>(v));
+
+        BOOST_TEST(std::uint16_t(42) == toml::get<std::uint16_t>(std::move(v)));
     }
 }
 
@@ -157,9 +195,11 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_floating_type, value_type, test_value_typ
 {
     {
         value_type v(3.14);
-        BOOST_TEST(static_cast<float      >(3.14) == toml::get<float      >(v));
+        const double ref(3.14);
-        BOOST_TEST(static_cast<double     >(3.14) == toml::get<double     >(v));
+        BOOST_TEST(static_cast<float      >(ref) == toml::get<float      >(v));
-        BOOST_TEST(static_cast<long double>(3.14) == toml::get<long double>(v));
+        BOOST_TEST(                         ref  == toml::get<double     >(v));
+        BOOST_TEST(static_cast<long double>(ref) == toml::get<long double>(v));
+        BOOST_TEST(static_cast<float      >(ref) == toml::get<float>(std::move(v)));
     }
 }
 
@@ -170,12 +210,18 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_string_type, value_type, test_value_types
         BOOST_TEST("foo" == toml::get<std::string>(v));
         toml::get<std::string>(v) += "bar";
         BOOST_TEST("foobar" == toml::get<std::string>(v));
+
+        const auto x = toml::get<std::string>(std::move(v));
+        BOOST_TEST("foobar" == x);
     }
     {
         value_type v("foo", toml::string_t::literal);
         BOOST_TEST("foo" == toml::get<std::string>(v));
         toml::get<std::string>(v) += "bar";
         BOOST_TEST("foobar" == toml::get<std::string>(v));
+
+        const auto x = toml::get<std::string>(std::move(v));
+        BOOST_TEST("foobar" == x);
     }
 
 #if __cplusplus >= 201703L
@@ -192,6 +238,7 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_string_type, value_type, test_value_types
 
 BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_array, value_type, test_value_types)
 {
+    {
         const value_type v{42, 54, 69, 72};
 
         const std::vector<int>         vec = toml::get<std::vector<int>>(v);
@@ -215,14 +262,14 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_array, value_type, test_value_types)
         BOOST_TEST(static_cast<std::int64_t>(72) == deq.at(3));
 
         std::array<int, 4> ary = toml::get<std::array<int, 4>>(v);
-    BOOST_TEST(static_cast<int>(42) == ary.at(0));
+        BOOST_TEST(42 == ary.at(0));
-    BOOST_TEST(static_cast<int>(54) == ary.at(1));
+        BOOST_TEST(54 == ary.at(1));
-    BOOST_TEST(static_cast<int>(69) == ary.at(2));
+        BOOST_TEST(69 == ary.at(2));
-    BOOST_TEST(static_cast<int>(72) == ary.at(3));
+        BOOST_TEST(72 == ary.at(3));
 
         std::tuple<int, short, unsigned, long> tpl =
             toml::get<std::tuple<int, short, unsigned, long>>(v);
-    BOOST_TEST(static_cast<int     >(42) == std::get<0>(tpl));
+        BOOST_TEST(                      42  == std::get<0>(tpl));
         BOOST_TEST(static_cast<short   >(54) == std::get<1>(tpl));
         BOOST_TEST(static_cast<unsigned>(69) == std::get<2>(tpl));
         BOOST_TEST(static_cast<long    >(72) == std::get<3>(tpl));
@@ -231,10 +278,55 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_array, value_type, test_value_types)
         std::pair<double, double> pr = toml::get<std::pair<double, double> >(p);
         BOOST_TEST(3.14 == pr.first);
         BOOST_TEST(2.71 == pr.second);
+    }
+
+    {
+        value_type v{42, 54, 69, 72};
+        const std::vector<int> vec = toml::get<std::vector<int>>(std::move(v));
+        BOOST_TEST(42 == vec.at(0));
+        BOOST_TEST(54 == vec.at(1));
+        BOOST_TEST(69 == vec.at(2));
+        BOOST_TEST(72 == vec.at(3));
+    }
+    {
+        value_type v{42, 54, 69, 72};
+        const std::deque<int> deq = toml::get<std::deque<int>>(std::move(v));
+        BOOST_TEST(42 == deq.at(0));
+        BOOST_TEST(54 == deq.at(1));
+        BOOST_TEST(69 == deq.at(2));
+        BOOST_TEST(72 == deq.at(3));
+    }
+    {
+        value_type v{42, 54, 69, 72};
+        const std::list<int> lst = toml::get<std::list<int>>(std::move(v));
+        std::list<int>::const_iterator iter = lst.begin();
+        BOOST_TEST(42 == *(iter++));
+        BOOST_TEST(54 == *(iter++));
+        BOOST_TEST(69 == *(iter++));
+        BOOST_TEST(72 == *(iter++));
+    }
+    {
+        value_type v{42, 54, 69, 72};
+        std::array<int, 4> ary = toml::get<std::array<int, 4>>(std::move(v));
+        BOOST_TEST(42 == ary.at(0));
+        BOOST_TEST(54 == ary.at(1));
+        BOOST_TEST(69 == ary.at(2));
+        BOOST_TEST(72 == ary.at(3));
+    }
+    {
+        value_type v{42, 54, 69, 72};
+        std::tuple<int, short, unsigned, long> tpl =
+            toml::get<std::tuple<int, short, unsigned, long>>(std::move(v));
+        BOOST_TEST(                      42  == std::get<0>(tpl));
+        BOOST_TEST(static_cast<short   >(54) == std::get<1>(tpl));
+        BOOST_TEST(static_cast<unsigned>(69) == std::get<2>(tpl));
+        BOOST_TEST(static_cast<long    >(72) == std::get<3>(tpl));
+    }
 }
 
 BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_array_of_array, value_type, test_value_types)
 {
+    {
         const value_type v1{42, 54, 69, 72};
         const value_type v2{"foo", "bar", "baz"};
         const value_type v{v1, v2};
@@ -242,11 +334,13 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_array_of_array, value_type, test_val
         std::pair<std::vector<int>, std::vector<std::string>> p =
             toml::get<std::pair<std::vector<int>, std::vector<std::string>>>(v);
 
+        BOOST_TEST(p.first.size() == 4u);
         BOOST_TEST(p.first.at(0) == 42);
         BOOST_TEST(p.first.at(1) == 54);
         BOOST_TEST(p.first.at(2) == 69);
         BOOST_TEST(p.first.at(3) == 72);
 
+        BOOST_TEST(p.second.size() == 3u);
         BOOST_TEST(p.second.at(0) == "foo");
         BOOST_TEST(p.second.at(1) == "bar");
         BOOST_TEST(p.second.at(2) == "baz");
@@ -262,10 +356,31 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_array_of_array, value_type, test_val
         BOOST_TEST(std::get<1>(t).at(0) == "foo");
         BOOST_TEST(std::get<1>(t).at(1) == "bar");
         BOOST_TEST(std::get<1>(t).at(2) == "baz");
+    }
+    {
+        const value_type v1{42, 54, 69, 72};
+        const value_type v2{"foo", "bar", "baz"};
+        value_type v{v1, v2};
+
+        std::pair<std::vector<int>, std::vector<std::string>> p =
+            toml::get<std::pair<std::vector<int>, std::vector<std::string>>>(std::move(v));
+
+        BOOST_TEST(p.first.size() == 4u);
+        BOOST_TEST(p.first.at(0) == 42);
+        BOOST_TEST(p.first.at(1) == 54);
+        BOOST_TEST(p.first.at(2) == 69);
+        BOOST_TEST(p.first.at(3) == 72);
+
+        BOOST_TEST(p.second.size() == 3u);
+        BOOST_TEST(p.second.at(0) == "foo");
+        BOOST_TEST(p.second.at(1) == "bar");
+        BOOST_TEST(p.second.at(2) == "baz");
+    }
 }
 
 BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_table, value_type, test_value_types)
 {
+    {
         const value_type v1{
                 {"key1", 1},
                 {"key2", 2},
@@ -278,6 +393,21 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_table, value_type, test_value_types)
         BOOST_TEST(v.at("key2") == 2);
         BOOST_TEST(v.at("key3") == 3);
         BOOST_TEST(v.at("key4") == 4);
+    }
+    {
+        value_type v1{
+                {"key1", 1},
+                {"key2", 2},
+                {"key3", 3},
+                {"key4", 4}
+            };
+        const auto v = toml::get<std::map<std::string, int>>(std::move(v1));
+        BOOST_TEST(v.at("key1") == 1);
+        BOOST_TEST(v.at("key2") == 2);
+        BOOST_TEST(v.at("key3") == 3);
+        BOOST_TEST(v.at("key4") == 4);
+    }
+
 }
 
 BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_toml_local_date, value_type, test_value_types)

tests/test_get_or.cpp

@@ -25,6 +25,11 @@ using test_value_types = std::tuple<
 
 namespace test
 {
+// to compare result values in BOOST_TEST().
+//
+// BOOST_TEST outputs the expected and actual values. Thus it includes the
+// output stream operator inside. To compile it, we need operator<<s for
+// containers to compare.
 template<typename charT, typename traits, typename T, typename Alloc>
 std::basic_ostream<charT, traits>&
 operator<<(std::basic_ostream<charT, traits>& os, const std::vector<T, Alloc>& v)
@@ -121,6 +126,55 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_or_exact, value_type, test_value_types)
 }
 #undef TOML11_TEST_GET_OR_EXACT
 
+#define TOML11_TEST_GET_OR_MOVE_EXACT(toml_type, init_expr, opt_expr)\
+    {                                                                \
+        using namespace test;                                        \
+        const toml::toml_type init init_expr ;                       \
+        toml::toml_type       opt  opt_expr ;                        \
+        value_type v(init);                                          \
+        BOOST_TEST(init != opt);                                     \
+        const auto opt_ = toml::get_or(std::move(v), std::move(opt));\
+        BOOST_TEST(init == opt_);                                    \
+    }                                                                \
+    /**/
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(test_get_or_move, value_type, test_value_types)
+{
+    TOML11_TEST_GET_OR_MOVE_EXACT(boolean,         ( true), (false))
+    TOML11_TEST_GET_OR_MOVE_EXACT(integer,         (   42), (   54))
+    TOML11_TEST_GET_OR_MOVE_EXACT(floating,        ( 3.14), ( 2.71))
+    TOML11_TEST_GET_OR_MOVE_EXACT(string,          ("foo"), ("bar"))
+    TOML11_TEST_GET_OR_MOVE_EXACT(local_time,      (12, 30, 45), (6, 0, 30))
+    TOML11_TEST_GET_OR_MOVE_EXACT(local_date,      (2019, toml::month_t::Apr, 1),
+                                                   (1999, toml::month_t::Jan, 2))
+    TOML11_TEST_GET_OR_MOVE_EXACT(local_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30))
+            )
+    TOML11_TEST_GET_OR_MOVE_EXACT(offset_datetime,
+            (toml::local_date(2019, toml::month_t::Apr, 1), toml::local_time(12, 30, 45), toml::time_offset( 9, 0)),
+            (toml::local_date(1999, toml::month_t::Jan, 2), toml::local_time( 6,  0, 30), toml::time_offset(-3, 0))
+            )
+    {
+        const typename value_type::array_type init{1,2,3,4,5};
+        typename value_type::array_type opt {6,7,8,9,10};
+        value_type v(init);
+        BOOST_TEST(init != opt);
+        const auto opt_ = toml::get_or(std::move(v), std::move(opt));
+        BOOST_TEST(init == opt_);
+    }
+    {
+        const typename value_type::table_type init{{"key1", 42}, {"key2", "foo"}};
+        typename value_type::table_type opt {{"key1", 54}, {"key2", "bar"}};
+        value_type v(init);
+        BOOST_TEST(init != opt);
+        const auto opt_ = toml::get_or(std::move(v), std::move(opt));
+        BOOST_TEST(init == opt_);
+    }
+}
+#undef TOML11_TEST_GET_OR_MOVE_EXACT
+
+
 #define TOML11_TEST_GET_OR_MODIFY(toml_type, init_expr, opt_expr)\
     {                                                            \
         using namespace test;                                    \
@@ -309,6 +363,13 @@ BOOST_AUTO_TEST_CASE(test_get_or_integer)
         BOOST_TEST(42u == toml::get_or(v1, 0u));
         BOOST_TEST(0u ==  toml::get_or(v2, 0u));
     }
+    {
+        toml::value v1(42);
+        toml::value v2(3.14);
+        BOOST_TEST(42u == toml::get_or(std::move(v1), 0u));
+        BOOST_TEST(0u ==  toml::get_or(std::move(v2), 0u));
+    }
+
 }
 
 BOOST_AUTO_TEST_CASE(test_get_or_floating)
@@ -319,6 +380,12 @@ BOOST_AUTO_TEST_CASE(test_get_or_floating)
         BOOST_TEST(2.71f == toml::get_or(v1, 2.71f));
         BOOST_TEST(static_cast<float>(v2.as_floating()) == toml::get_or(v2, 2.71f));
     }
+    {
+        toml::value v1(42);
+        toml::value v2(3.14);
+        BOOST_TEST(2.71f                    == toml::get_or(std::move(v1), 2.71f));
+        BOOST_TEST(static_cast<float>(3.14) == toml::get_or(std::move(v2), 2.71f));
+    }
 }
 
 BOOST_AUTO_TEST_CASE(test_get_or_string)
@@ -345,7 +412,16 @@ BOOST_AUTO_TEST_CASE(test_get_or_string)
         BOOST_TEST("foobar" == toml::get_or(v1, std::move(s1)));
         BOOST_TEST("bazqux" == toml::get_or(v2, std::move(s1)));
     }
+    {
+        toml::value v1("foobar");
+        toml::value v2(42);
 
+        std::string       s1("bazqux");
+        const std::string s2("bazqux");
+
+        BOOST_TEST("foobar" == toml::get_or(std::move(v1), s1));
+        BOOST_TEST("bazqux" == toml::get_or(std::move(v2), s1));
+    }
     {
         toml::value v1("foobar");
         toml::value v2(42);
@@ -357,4 +433,20 @@ BOOST_AUTO_TEST_CASE(test_get_or_string)
         BOOST_TEST("foobar" == toml::get_or(v1, lit));
         BOOST_TEST("bazqux" == toml::get_or(v2, lit));
     }
+    {
+        toml::value v1("foobar");
+        toml::value v2(42);
+
+        BOOST_TEST("foobar" == toml::get_or(std::move(v1), "bazqux"));
+        BOOST_TEST("bazqux" == toml::get_or(std::move(v2), "bazqux"));
+    }
+    {
+        toml::value v1("foobar");
+        toml::value v2(42);
+
+        const char* lit = "bazqux";
+        BOOST_TEST("foobar" == toml::get_or(v1, lit));
+        BOOST_TEST("bazqux" == toml::get_or(v2, lit));
+    }
+
 }

tests/test_lex_floating.cpp

@@ -51,10 +51,18 @@ BOOST_AUTO_TEST_CASE(test_exponential_valid)
     TOML11_TEST_LEX_ACCEPT(lex_float, "123E-10",    "123E-10");
     TOML11_TEST_LEX_ACCEPT(lex_float, "1_2_3E-10",  "1_2_3E-10");
     TOML11_TEST_LEX_ACCEPT(lex_float, "1_2_3E-1_0", "1_2_3E-1_0");
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1_2_3E-01",  "1_2_3E-01");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1_2_3E-0_1", "1_2_3E-0_1");
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_exponential_invalid)
 {
+    // accept partially
     TOML11_TEST_LEX_ACCEPT(lex_float, "1e1E0", "1e1");
     TOML11_TEST_LEX_ACCEPT(lex_float, "1E1e0", "1E1");
 }
@@ -64,12 +72,26 @@ BOOST_AUTO_TEST_CASE(test_both_valid)
     TOML11_TEST_LEX_ACCEPT(lex_float, "6.02e23",          "6.02e23");
     TOML11_TEST_LEX_ACCEPT(lex_float, "6.02e+23",         "6.02e+23");
     TOML11_TEST_LEX_ACCEPT(lex_float, "1.112_650_06e-17", "1.112_650_06e-17");
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1.0e-07",          "1.0e-07");
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_both_invalid)
 {
-    TOML11_TEST_LEX_ACCEPT(lex_float, "1e1.0",  "1e1");
     TOML11_TEST_LEX_REJECT(lex_float, "01e1.0");
+    // accept partially
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1e1.0",  "1e1");
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1.0e_01",  "1.0");
+    TOML11_TEST_LEX_ACCEPT(lex_float, "1.0e0__1", "1.0e0");
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_special_floating_point)

tests/test_literals.cpp

@@ -45,6 +45,16 @@ BOOST_AUTO_TEST_CASE(test_file_as_literal)
             b = "baz"
         )"_toml;
 
+        BOOST_TEST(r == v);
+    }
+    {
+        const toml::value r{
+            {"array_of_tables", toml::array{toml::table{}}}
+        };
+        const toml::value v = u8R"(
+            [[array_of_tables]]
+        )"_toml;
+
         BOOST_TEST(r == v);
     }
 }

tests/test_parse_array.cpp

@@ -128,3 +128,47 @@ BOOST_AUTO_TEST_CASE(test_multiline_array_value)
         TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\",#comment\n\"b#r\",#comment\n\"b#z\"#comment\n]", toml::value(a));
     }
 }
+
+BOOST_AUTO_TEST_CASE(test_heterogeneous_array)
+{
+#ifndef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("In strict TOML v0.5.0, heterogeneous arrays are not allowed.");
+#else
+    {
+        array a(5);
+        a[0] = toml::value("foo");
+        a[1] = toml::value(3.14);
+        a[2] = toml::value(42);
+        a[3] = toml::value{toml::value("array"), toml::value("of"), toml::value("hetero-array"), toml::value(1)};
+        a[4] = toml::value{{"key", "value"}};
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\", 3.14, 42, [\"array\", \"of\", \"hetero-array\", 1], {key = \"value\"}]", toml::value(a));
+    }
+    {
+        array a(5);
+        a[0] = toml::value("foo");
+        a[1] = toml::value(3.14);
+        a[2] = toml::value(42);
+        a[3] = toml::value{toml::value("array"), toml::value("of"), toml::value("hetero-array"), toml::value(1)};
+        a[4] = toml::value{{"key", "value"}};
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\",\n 3.14,\n 42,\n [\"array\", \"of\", \"hetero-array\", 1],\n {key = \"value\"},\n]", toml::value(a));
+    }
+    {
+        array a(5);
+        a[0] = toml::value("foo");
+        a[1] = toml::value(3.14);
+        a[2] = toml::value(42);
+        a[3] = toml::value{toml::value("array"), toml::value("of"), toml::value("hetero-array"), toml::value(1)};
+        a[4] = toml::value{{"key", "value"}};
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\",#comment\n 3.14,#comment\n 42,#comment\n [\"array\", \"of\", \"hetero-array\", 1],#comment\n {key = \"value\"},#comment\n]#comment", toml::value(a));
+    }
+    {
+        array a(5);
+        a[0] = toml::value("foo");
+        a[1] = toml::value(3.14);
+        a[2] = toml::value(42);
+        a[3] = toml::value{toml::value("array"), toml::value("of"), toml::value("hetero-array"), toml::value(1)};
+        a[4] = toml::value{{"key", "value"}};
+        TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "[\"foo\",\n 3.14,\n 42,\n [\"array\",\n \"of\",\n \"hetero-array\",\n 1],\n {key = \"value\"},\n]", toml::value(a));
+    }
+#endif
+}

tests/test_parse_floating.cpp

@@ -68,6 +68,13 @@ BOOST_AUTO_TEST_CASE(test_exponential)
     TOML11_TEST_PARSE_EQUAL(parse_floating, "1_2_3E-1_0", 123e-10);
     TOML11_TEST_PARSE_EQUAL(parse_floating, "+0e0",        0.0);
     TOML11_TEST_PARSE_EQUAL(parse_floating, "-0e0",       -0.0);
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_PARSE_EQUAL(parse_floating, "1_2_3E-01",  123e-1);
+    TOML11_TEST_PARSE_EQUAL(parse_floating, "1_2_3E-0_1", 123e-1);
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_exponential_value)
@@ -90,6 +97,13 @@ BOOST_AUTO_TEST_CASE(test_exponential_value)
     TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1_2_3E-1_0", value(123e-10));
     TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "+0e0",       value( 0.0));
     TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "-0e0",       value(-0.0));
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1_2_3E-01",  value(123e-1));
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1_2_3E-0_1", value(123e-1));
+#endif
 }
 BOOST_AUTO_TEST_CASE(test_fe)
 {
@@ -102,6 +116,12 @@ BOOST_AUTO_TEST_CASE(test_fe_vaule)
     TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "6.02e23",          value(6.02e23));
     TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "6.02e+23",         value(6.02e23));
     TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "1.112_650_06e-17", value(1.11265006e-17));
+
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+    BOOST_TEST_MESSAGE("testing an unreleased toml feature: leading zeroes in float exponent part");
+    // toml-lang/toml master permits leading 0s in exp part (unreleased)
+    TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "3.141_5e-01",      value(3.1415e-1));
+#endif
 }
 
 BOOST_AUTO_TEST_CASE(test_inf)

tests/test_parse_inline_table.cpp

@@ -46,3 +46,19 @@ BOOST_AUTO_TEST_CASE(test_inline_table_value)
         TOML11_TEST_PARSE_EQUAL_VALUE(parse_value<toml::value>, "{type.name = \"pug\"}", value(t));
     }
 }
+
+BOOST_AUTO_TEST_CASE(test_inline_table_immutability)
+{
+    {
+        std::istringstream stream(std::string(
+                "a = {b = 1}\n"
+                "a.c = 2\n"));
+        BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
+    }
+    {
+        std::istringstream stream(std::string(
+                "a = {b = {c = 1}}\n"
+                "a.b.d = 2\n"));
+        BOOST_CHECK_THROW(toml::parse(stream), toml::syntax_error);
+    }
+}

tests/test_string.cpp

@@ -111,3 +111,44 @@ BOOST_AUTO_TEST_CASE(test_literal_ml_string)
     }
 }
 
+BOOST_AUTO_TEST_CASE(test_string_add_assign)
+{
+    // string literal
+    {
+        toml::string str("foo");
+        str += "bar";
+        BOOST_TEST(str.str == "foobar");
+    }
+    // std::string
+    {
+        toml::string str("foo");
+        std::string str2("bar");
+        str += str2;
+        BOOST_TEST(str.str == "foobar");
+    }
+    // toml::string
+    {
+        toml::string str("foo");
+        toml::string str2("bar");
+        str += str2;
+        BOOST_TEST(str.str == "foobar");
+    }
+#if __cplusplus >= 201703L
+    // std::string_view
+    {
+        toml::string str("foo");
+        str += std::string_view("bar");
+        BOOST_TEST(str == "foobar");
+    }
+#endif
+    // std::string += toml::string
+    {
+        std::string  str("foo");
+        toml::string str2("bar");
+        str += str2;
+        BOOST_TEST(str == "foobar");
+    }
+
+
+}
+

tests/test_value.cpp

@@ -905,3 +905,115 @@ BOOST_AUTO_TEST_CASE(test_value_empty)
     BOOST_CHECK_THROW(v1.as_array(),           toml::type_error);
     BOOST_CHECK_THROW(v1.as_table(),           toml::type_error);
 }
+
+
+BOOST_AUTO_TEST_CASE(test_value_at)
+{
+    {
+        toml::value v1{{"foo", 42}, {"bar", 3.14}, {"baz", "qux"}};
+
+        BOOST_TEST(v1.at("foo").as_integer()  == 42);
+        BOOST_TEST(v1.at("bar").as_floating() == 3.14);
+        BOOST_TEST(v1.at("baz").as_string()   == "qux");
+
+        BOOST_CHECK_THROW(v1.at(0), toml::type_error);
+        BOOST_CHECK_THROW(v1.at("quux"), std::out_of_range);
+    }
+
+
+    {
+        toml::value v1{1,2,3,4,5};
+
+        BOOST_TEST(v1.at(0).as_integer() == 1);
+        BOOST_TEST(v1.at(1).as_integer() == 2);
+        BOOST_TEST(v1.at(2).as_integer() == 3);
+        BOOST_TEST(v1.at(3).as_integer() == 4);
+        BOOST_TEST(v1.at(4).as_integer() == 5);
+
+        BOOST_CHECK_THROW(v1.at("foo"), toml::type_error);
+        BOOST_CHECK_THROW(v1.at(5),     std::out_of_range);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_value_bracket)
+{
+    {
+        toml::value v1{{"foo", 42}, {"bar", 3.14}, {"baz", "qux"}};
+
+        BOOST_TEST(v1["foo"].as_integer()  == 42);
+        BOOST_TEST(v1["bar"].as_floating() == 3.14);
+        BOOST_TEST(v1["baz"].as_string()   == "qux");
+
+        v1["qux"] = 54;
+        BOOST_TEST(v1["qux"].as_integer()  == 54);
+    }
+    {
+        toml::value v1;
+        v1["foo"] = 42;
+
+        BOOST_TEST(v1.is_table());
+        BOOST_TEST(v1["foo"].as_integer()  == 42);
+    }
+    {
+        toml::value v1{1,2,3,4,5};
+
+        BOOST_TEST(v1[0].as_integer() == 1);
+        BOOST_TEST(v1[1].as_integer() == 2);
+        BOOST_TEST(v1[2].as_integer() == 3);
+        BOOST_TEST(v1[3].as_integer() == 4);
+        BOOST_TEST(v1[4].as_integer() == 5);
+
+        BOOST_CHECK_THROW(v1["foo"], toml::type_error);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_value_map_methods)
+{
+    {
+        toml::value v1{{"foo", 42}, {"bar", 3.14}, {"baz", "qux"}};
+
+        BOOST_TEST(v1.count("foo") == 1u);
+        BOOST_TEST(v1.count("bar") == 1u);
+        BOOST_TEST(v1.count("baz") == 1u);
+        BOOST_TEST(v1.count("qux") == 0u);
+
+        BOOST_TEST( v1.contains("foo"));
+        BOOST_TEST( v1.contains("bar"));
+        BOOST_TEST( v1.contains("baz"));
+        BOOST_TEST(!v1.contains("qux"));
+
+        BOOST_TEST(v1.size() == 3);
+
+        v1["qux"] = 54;
+        BOOST_TEST(v1.count("qux") == 1u);
+        BOOST_TEST(v1.contains("qux"));
+        BOOST_TEST(v1.size() == 4);
+    }
+    {
+        toml::value v1(42);
+        BOOST_CHECK_THROW(v1.size()       , toml::type_error);
+        BOOST_CHECK_THROW(v1.count("k")   , toml::type_error);
+        BOOST_CHECK_THROW(v1.contains("k"), toml::type_error);
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_value_vector_methods)
+{
+    {
+        toml::value v1{1, 2, 3, 4, 5};
+
+        BOOST_TEST(v1.size() == 5);
+
+        v1.push_back(6);
+        BOOST_TEST(v1.size() == 6);
+
+        v1.emplace_back(6);
+        BOOST_TEST(v1.size() == 7);
+    }
+    {
+        toml::value v1(42);
+        BOOST_CHECK_THROW(v1.size(),          toml::type_error);
+        BOOST_CHECK_THROW(v1.push_back(1),    toml::type_error);
+        BOOST_CHECK_THROW(v1.emplace_back(1), toml::type_error);
+    }
+}

toml/color.hpp

@@ -0,0 +1,64 @@
+#ifndef TOML11_COLOR_HPP
+#define TOML11_COLOR_HPP
+#include <ostream>
+#include <cstdint>
+
+#ifdef TOML11_COLORIZE_ERROR_MESSAGE
+#define TOML11_ERROR_MESSAGE_COLORIZED true
+#else
+#define TOML11_ERROR_MESSAGE_COLORIZED false
+#endif
+
+namespace toml
+{
+
+// put ANSI escape sequence to ostream
+namespace color_ansi
+{
+namespace detail
+{
+inline int colorize_index()
+{
+    static const int index = std::ios_base::xalloc();
+    return index;
+}
+} // detail
+
+inline std::ostream& colorize(std::ostream& os)
+{
+    // by default, it is zero.
+    os.iword(detail::colorize_index()) = 1;
+    return os;
+}
+inline std::ostream& nocolorize(std::ostream& os)
+{
+    os.iword(detail::colorize_index()) = 0;
+    return os;
+}
+inline std::ostream& reset  (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[00m";} return os;}
+inline std::ostream& bold   (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[01m";} return os;}
+inline std::ostream& grey   (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[30m";} return os;}
+inline std::ostream& red    (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[31m";} return os;}
+inline std::ostream& green  (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[32m";} return os;}
+inline std::ostream& yellow (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[33m";} return os;}
+inline std::ostream& blue   (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[34m";} return os;}
+inline std::ostream& magenta(std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[35m";} return os;}
+inline std::ostream& cyan   (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[36m";} return os;}
+inline std::ostream& white  (std::ostream& os)
+{if(os.iword(detail::colorize_index()) == 1) {os << "\033[37m";} return os;}
+} // color_ansi
+
+// ANSI escape sequence is the only and default colorization method currently
+namespace color = color_ansi;
+
+} // toml
+#endif// TOML11_COLOR_HPP

toml/combinator.hpp

@@ -45,6 +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);
+        (void) r; // Unused variable warning
         assert(r == static_cast<int>(buf.size()) - 1);
         return std::string(buf.data());
     }

toml/datetime.hpp

@@ -20,7 +20,7 @@ namespace toml
 namespace detail
 {
 // TODO: find more sophisticated way to handle this
-#if _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _BSD_SOURCE || _SVID_SOURCE || _POSIX_SOURCE
+#if _POSIX_C_SOURCE >= 1 || defined(_XOPEN_SOURCE) || defined(_BSD_SOURCE) || defined(_SVID_SOURCE) || defined(_POSIX_SOURCE)
 inline std::tm localtime_s(const std::time_t* src)
 {
     std::tm dst;
@@ -28,6 +28,13 @@ inline std::tm localtime_s(const std::time_t* src)
     if (!result) { throw std::runtime_error("localtime_r failed."); }
     return dst;
 }
+inline std::tm gmtime_s(const std::time_t* src)
+{
+    std::tm dst;
+    const auto result = ::gmtime_r(src, &dst);
+    if (!result) { throw std::runtime_error("gmtime_r failed."); }
+    return dst;
+}
 #elif _MSC_VER
 inline std::tm localtime_s(const std::time_t* src)
 {
@@ -36,13 +43,26 @@ inline std::tm localtime_s(const std::time_t* src)
     if (result) { throw std::runtime_error("localtime_s failed."); }
     return dst;
 }
-#else
+inline std::tm gmtime_s(const std::time_t* src)
+{
+    std::tm dst;
+    const auto result = ::gmtime_s(&dst, src);
+    if (result) { throw std::runtime_error("gmtime_s failed."); }
+    return dst;
+}
+#else // fallback. not threadsafe
 inline std::tm localtime_s(const std::time_t* src)
 {
     const auto result = std::localtime(src);
     if (!result) { throw std::runtime_error("localtime failed."); }
     return *result;
 }
+inline std::tm gmtime_s(const std::time_t* src)
+{
+    const auto result = std::gmtime(src);
+    if (!result) { throw std::runtime_error("gmtime failed."); }
+    return *result;
+}
 #endif
 } // detail
 
@@ -153,8 +173,8 @@ std::basic_ostream<charT, traits>&
 operator<<(std::basic_ostream<charT, traits>& os, const local_date& date)
 {
     os << std::setfill('0') << std::setw(4) << static_cast<int>(date.year )     << '-';
-    os << std::setfill('0') << std::setw(2) << static_cast<int>(date.month + 1) << '-';
+    os << std::setfill('0') << std::setw(2) << static_cast<int>(date.month) + 1 << '-';
-    os << std::setfill('0') << std::setw(2) << static_cast<int>(date.day      );
+    os << std::setfill('0') << std::setw(2) << static_cast<int>(date.day  )    ;
     return os;
 }
 
@@ -378,10 +398,31 @@ struct local_datetime
     {
         using internal_duration =
             typename std::chrono::system_clock::time_point::duration;
+
+        // Normally DST begins at A.M. 3 or 4. If we re-use conversion operator
+        // of local_date and local_time independently, the conversion fails if
+        // it is the day when DST begins or ends. Since local_date considers the
+        // time is 00:00 A.M. and local_time does not consider DST because it
+        // does not have any date information. We need to consider both date and
+        // time information at the same time to convert it correctly.
+
+        std::tm t;
+        t.tm_sec   = static_cast<int>(this->time.second);
+        t.tm_min   = static_cast<int>(this->time.minute);
+        t.tm_hour  = static_cast<int>(this->time.hour);
+        t.tm_mday  = static_cast<int>(this->date.day);
+        t.tm_mon   = static_cast<int>(this->date.month);
+        t.tm_year  = static_cast<int>(this->date.year) - 1900;
+        t.tm_wday  = 0; // the value will be ignored
+        t.tm_yday  = 0; // the value will be ignored
+        t.tm_isdst = -1;
+
         // std::mktime returns date as local time zone. no conversion needed
-        auto dt = std::chrono::system_clock::time_point(this->date);
+        auto dt = std::chrono::system_clock::from_time_t(std::mktime(&t));
         dt += std::chrono::duration_cast<internal_duration>(
-                   std::chrono::nanoseconds(this->time));
+                std::chrono::milliseconds(this->time.millisecond) +
+                std::chrono::microseconds(this->time.microsecond) +
+                std::chrono::nanoseconds (this->time.nanosecond));
         return dt;
     }
 
@@ -447,40 +488,71 @@ struct offset_datetime
         : date(dt.date), time(dt.time), offset(o)
     {}
     explicit offset_datetime(const local_datetime& ld)
-        : date(ld.date), time(ld.time), offset(get_local_offset())
+        : date(ld.date), time(ld.time), offset(get_local_offset(nullptr))
+          // use the current local timezone offset
     {}
     explicit offset_datetime(const std::chrono::system_clock::time_point& tp)
-        : offset_datetime(local_datetime(tp))
+        : offset(0, 0) // use gmtime
-    {}
+    {
+        const auto timet = std::chrono::system_clock::to_time_t(tp);
+        const auto tm    = detail::gmtime_s(&timet);
+        this->date = local_date(tm);
+        this->time = local_time(tm);
+    }
     explicit offset_datetime(const std::time_t& t)
-        : offset_datetime(local_datetime(t))
+        : offset(0, 0) // use gmtime
-    {}
+    {
+        const auto tm    = detail::gmtime_s(&t);
+        this->date = local_date(tm);
+        this->time = local_time(tm);
+    }
     explicit offset_datetime(const std::tm& t)
-        : offset_datetime(local_datetime(t))
+        : offset(0, 0) // assume gmtime
-    {}
+    {
+        this->date = local_date(t);
+        this->time = local_time(t);
+    }
 
     operator std::chrono::system_clock::time_point() const
     {
         // get date-time
         using internal_duration =
             typename std::chrono::system_clock::time_point::duration;
-        std::chrono::system_clock::time_point tp =
-            std::chrono::system_clock::time_point(this->date) +
-            std::chrono::duration_cast<internal_duration>(
-                   std::chrono::nanoseconds(this->time));
 
-        // get date-time in UTC. let's say we are in +09:00 (JPN).
+        // first, convert it to local date-time information in the same way as
-        // writing 12:00:00 in +09:00 means 03:00:00Z. to represent
+        // local_datetime does. later we will use time_t to adjust time offset.
-        // 12:00:00Z, first we need to add +09:00.
+        std::tm t;
-        const auto ofs = get_local_offset();
+        t.tm_sec   = static_cast<int>(this->time.second);
+        t.tm_min   = static_cast<int>(this->time.minute);
+        t.tm_hour  = static_cast<int>(this->time.hour);
+        t.tm_mday  = static_cast<int>(this->date.day);
+        t.tm_mon   = static_cast<int>(this->date.month);
+        t.tm_year  = static_cast<int>(this->date.year) - 1900;
+        t.tm_wday  = 0; // the value will be ignored
+        t.tm_yday  = 0; // the value will be ignored
+        t.tm_isdst = -1;
+        const std::time_t tp_loc = std::mktime(std::addressof(t));
+
+        auto tp = std::chrono::system_clock::from_time_t(tp_loc);
+        tp += std::chrono::duration_cast<internal_duration>(
+                std::chrono::milliseconds(this->time.millisecond) +
+                std::chrono::microseconds(this->time.microsecond) +
+                std::chrono::nanoseconds (this->time.nanosecond));
+
+        // Since mktime uses local time zone, it should be corrected.
+        // `12:00:00+09:00` means `03:00:00Z`. So mktime returns `03:00:00Z` if
+        // we are in `+09:00` timezone. To represent `12:00:00Z` there, we need
+        // to add `+09:00` to `03:00:00Z`.
+        //    Here, it uses the time_t converted from date-time info to handle
+        // daylight saving time.
+        const auto ofs = get_local_offset(std::addressof(tp_loc));
         tp += std::chrono::hours  (ofs.hour);
         tp += std::chrono::minutes(ofs.minute);
 
-        // here, tp represents 12:00:00 in UTC but we have offset information.
+        // We got `12:00:00Z` by correcting local timezone applied by mktime.
-        // we need to subtract it. For example, let's say the input is
+        // Then we will apply the offset. Let's say `12:00:00-08:00` is given.
-        // 12:00:00-08:00. now we have tp = 12:00:00Z as a result of the above
+        // And now, we have `12:00:00Z`. `12:00:00-08:00` means `20:00:00Z`.
-        // conversion. But the actual time we need to return is 20:00:00Z
+        // So we need to subtract the offset.
-        // because of -08:00.
         tp -= std::chrono::minutes(this->offset);
         return tp;
     }
@@ -500,11 +572,10 @@ struct offset_datetime
 
   private:
 
-    static time_offset get_local_offset()
+    static time_offset get_local_offset(const std::time_t* tp)
     {
-         // get current timezone
+        // get local timezone with the same date-time information as mktime
-        const auto tmp1 = std::time(nullptr);
+        const auto t = detail::localtime_s(tp);
-        const auto t    = detail::localtime_s(&tmp1);
 
         std::array<char, 6> buf;
         const auto result = std::strftime(buf.data(), 6, "%z", &t); // +hhmm\0

toml/exception.hpp

@@ -2,6 +2,7 @@
 // Distributed under the MIT License.
 #ifndef TOML11_EXCEPTION_HPP
 #define TOML11_EXCEPTION_HPP
+#include "source_location.hpp"
 #include <stdexcept>
 #include <string>
 
@@ -11,15 +12,21 @@ namespace toml
 struct exception : public std::exception
 {
   public:
+    explicit exception(const source_location& loc): loc_(loc) {}
     virtual ~exception() noexcept override = default;
     virtual const char* what() const noexcept override {return "";}
+    virtual source_location const& location() const noexcept {return loc_;}
+
+  protected:
+    source_location loc_;
 };
 
 struct syntax_error : public toml::exception
 {
   public:
-    explicit syntax_error(const std::string& what_arg) : what_(what_arg){}
+    explicit syntax_error(const std::string& what_arg, const source_location& loc)
-    explicit syntax_error(const char* what_arg)        : what_(what_arg){}
+        : exception(loc), what_(what_arg)
+    {}
     virtual ~syntax_error() noexcept override = default;
     virtual const char* what() const noexcept override {return what_.c_str();}
 
@@ -30,8 +37,9 @@ struct syntax_error : public toml::exception
 struct type_error : public toml::exception
 {
   public:
-    explicit type_error(const std::string& what_arg) : what_(what_arg){}
+    explicit type_error(const std::string& what_arg, const source_location& loc)
-    explicit type_error(const char* what_arg)        : what_(what_arg){}
+        : exception(loc), what_(what_arg)
+    {}
     virtual ~type_error() noexcept override = default;
     virtual const char* what() const noexcept override {return what_.c_str();}
 
@@ -42,10 +50,12 @@ struct type_error : public toml::exception
 struct internal_error : public toml::exception
 {
   public:
-    explicit internal_error(const std::string& what_arg) : what_(what_arg){}
+    explicit internal_error(const std::string& what_arg, const source_location& loc)
-    explicit internal_error(const char* what_arg)        : what_(what_arg){}
+        : exception(loc), what_(what_arg)
+    {}
     virtual ~internal_error() noexcept override = default;
     virtual const char* what() const noexcept override {return what_.c_str();}
+
   protected:
     std::string what_;
 };

toml/get.hpp

@@ -31,10 +31,10 @@ get(const basic_value<C, M, V>& v)
 
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V>
-detail::enable_if_t<detail::is_exact_toml_type<T, basic_value<C, M, V>>::value, T> &&
+detail::enable_if_t<detail::is_exact_toml_type<T, basic_value<C, M, V>>::value, T>
 get(basic_value<C, M, V>&& v)
 {
-    return std::move(v).template cast<detail::type_to_enum<T, basic_value<C, M, V>>::value>();
+    return T(std::move(v).template cast<detail::type_to_enum<T, basic_value<C, M, V>>::value>());
 }
 
 // ============================================================================
@@ -58,10 +58,10 @@ get(const basic_value<C, M, V>& v)
 
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V>
-inline detail::enable_if_t<std::is_same<T, basic_value<C, M, V>>::value, T> &&
+inline detail::enable_if_t<std::is_same<T, basic_value<C, M, V>>::value, T>
 get(basic_value<C, M, V>&& v)
 {
-    return std::move(v);
+    return basic_value<C, M, V>(std::move(v));
 }
 
 // ============================================================================
@@ -90,7 +90,7 @@ inline detail::enable_if_t<detail::conjunction<
     >::value, T>
 get(const basic_value<C, M, V>& v)
 {
-    return static_cast<T>(v.template cast<value_t::integer>());
+    return static_cast<T>(v.as_integer());
 }
 
 // ============================================================================
@@ -105,7 +105,7 @@ inline detail::enable_if_t<detail::conjunction<
     >::value, T>
 get(const basic_value<C, M, V>& v)
 {
-    return static_cast<T>(v.template cast<value_t::floating>());
+    return static_cast<T>(v.as_floating());
 }
 
 // ============================================================================
@@ -117,7 +117,7 @@ template<typename T, typename C,
 inline detail::enable_if_t<std::is_same<T, std::string>::value, std::string>&
 get(basic_value<C, M, V>& v)
 {
-    return v.template cast<value_t::string>().str;
+    return v.as_string().str;
 }
 
 template<typename T, typename C,
@@ -125,15 +125,15 @@ template<typename T, typename C,
 inline detail::enable_if_t<std::is_same<T, std::string>::value, std::string> const&
 get(const basic_value<C, M, V>& v)
 {
-    return v.template cast<value_t::string>().str;
+    return v.as_string().str;
 }
 
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V>
-inline detail::enable_if_t<std::is_same<T, std::string>::value, std::string> const&
+inline detail::enable_if_t<std::is_same<T, std::string>::value, std::string>
 get(basic_value<C, M, V>&& v)
 {
-    return std::move(v.template cast<value_t::string>().str);
+    return std::string(std::move(v.as_string().str));
 }
 
 // ============================================================================
@@ -145,7 +145,7 @@ template<typename T, typename C,
 inline detail::enable_if_t<std::is_same<T, std::string_view>::value, std::string_view>
 get(const basic_value<C, M, V>& v)
 {
-    return std::string_view(v.template cast<value_t::string>().str);
+    return std::string_view(v.as_string().str);
 }
 #endif
 
@@ -158,7 +158,7 @@ inline detail::enable_if_t<detail::is_chrono_duration<T>::value, T>
 get(const basic_value<C, M, V>& v)
 {
     return std::chrono::duration_cast<T>(
-            std::chrono::nanoseconds(v.template cast<value_t::local_time>()));
+            std::chrono::nanoseconds(v.as_local_time()));
 }
 
 // ============================================================================
@@ -174,26 +174,23 @@ get(const basic_value<C, M, V>& v)
     {
         case value_t::local_date:
         {
-            return std::chrono::system_clock::time_point(
+            return std::chrono::system_clock::time_point(v.as_local_date());
-                    v.template cast<value_t::local_date>());
         }
         case value_t::local_datetime:
         {
-            return std::chrono::system_clock::time_point(
+            return std::chrono::system_clock::time_point(v.as_local_datetime());
-                    v.template cast<value_t::local_datetime>());
         }
         case value_t::offset_datetime:
         {
-            return std::chrono::system_clock::time_point(
+            return std::chrono::system_clock::time_point(v.as_offset_datetime());
-                    v.template cast<value_t::offset_datetime>());
         }
         default:
         {
-            throw type_error(detail::format_underline("[error] toml::value "
+            throw type_error(detail::format_underline("toml::value: "
                 "bad_cast to std::chrono::system_clock::time_point", {
                     {std::addressof(detail::get_region(v)),
                      concat_to_string("the actual type is ", v.type())}
-                }));
+                }), v.location());
         }
     }
 }
@@ -259,9 +256,18 @@ get(const basic_value<C, M, V>&);
 // toml::from<T>::from_toml(v)
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V,
-         std::size_t S = sizeof(::toml::into<T>)>
+         std::size_t S = sizeof(::toml::from<T>)>
 T get(const basic_value<C, M, V>&);
 
+// T(const toml::value&) and T is not toml::basic_value
+template<typename T, typename C,
+         template<typename ...> class M, template<typename ...> class V>
+detail::enable_if_t<detail::conjunction<
+    detail::negation<detail::is_basic_value<T>>,
+    std::is_constructible<T, const basic_value<C, M, V>&>
+    >::value, T>
+get(const basic_value<C, M, V>&);
+
 // ============================================================================
 // array-like types; most likely STL container, like std::vector, etc.
 
@@ -276,7 +282,7 @@ detail::enable_if_t<detail::conjunction<
 get(const basic_value<C, M, V>& v)
 {
     using value_type = typename T::value_type;
-    const auto& ar = v.template cast<value_t::array>();
+    const auto& ar = v.as_array();
     T container;
     container.resize(ar.size());
     std::transform(ar.cbegin(), ar.cend(), container.begin(),
@@ -298,13 +304,13 @@ detail::enable_if_t<detail::conjunction<
 get(const basic_value<C, M, V>& v)
 {
     using value_type = typename T::value_type;
-    const auto& ar = v.template cast<value_t::array>();
+    const auto& ar = v.as_array();
 
     T container;
     if(ar.size() != container.size())
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[erorr] toml::get specified container size is ", container.size(),
+            "toml::get: specified container size is ", container.size(),
             " but there are ", ar.size(), " elements in toml array."), {
                 {std::addressof(detail::get_region(v)), "here"}
             }));
@@ -325,11 +331,11 @@ get(const basic_value<C, M, V>& v)
     using first_type  = typename T::first_type;
     using second_type = typename T::second_type;
 
-    const auto& ar = v.template cast<value_t::array>();
+    const auto& ar = v.as_array();
     if(ar.size() != 2)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[erorr] toml::get specified std::pair but there are ", ar.size(),
+            "toml::get: specified std::pair but there are ", ar.size(),
             " elements in toml array."), {
                 {std::addressof(detail::get_region(v)), "here"}
             }));
@@ -356,12 +362,12 @@ template<typename T, typename C,
 detail::enable_if_t<detail::is_std_tuple<T>::value, T>
 get(const basic_value<C, M, V>& v)
 {
-    const auto& ar = v.template cast<value_t::array>();
+    const auto& ar = v.as_array();
     if(ar.size() != std::tuple_size<T>::value)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[erorr] toml::get specified std::tuple with ",
+            "toml::get: specified std::tuple with ",
-            std::tuple_size<T>::value, "elements, but there are ", ar.size(),
+            std::tuple_size<T>::value, " elements, but there are ", ar.size(),
             " elements in toml array."), {
                 {std::addressof(detail::get_region(v)), "here"}
             }));
@@ -388,7 +394,7 @@ get(const basic_value<C, M, V>& v)
                   "toml::get only supports map type of which key_type is "
                   "convertible from std::string.");
     T map;
-    for(const auto& kv : v.template cast<value_t::table>())
+    for(const auto& kv : v.as_table())
     {
         map[key_type(kv.first)] = ::toml::get<mapped_type>(kv.second);
     }
@@ -420,8 +426,19 @@ T get(const basic_value<C, M, V>& v)
     return ::toml::from<T>::from_toml(v);
 }
 
+template<typename T, typename C,
+         template<typename ...> class M, template<typename ...> class V>
+detail::enable_if_t<detail::conjunction<
+    detail::negation<detail::is_basic_value<T>>,
+    std::is_constructible<T, const basic_value<C, M, V>&>
+    >::value, T>
+get(const basic_value<C, M, V>& v)
+{
+    return T(v);
+}
+
 // ============================================================================
-// find and get
+// find
 
 // ----------------------------------------------------------------------------
 // these overloads do not require to set T. and returns value itself.
@@ -429,11 +446,11 @@ template<typename C,
          template<typename ...> class M, template<typename ...> class V>
 basic_value<C, M, V> const& find(const basic_value<C, M, V>& v, const key& ky)
 {
-    const auto& tab = v.template cast<value_t::table>();
+    const auto& tab = v.as_table();
     if(tab.count(ky) == 0)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[error] key \"", ky, "\" not found"), {
+            "key \"", ky, "\" not found"), {
                 {std::addressof(detail::get_region(v)), "in this table"}
             }));
     }
@@ -443,11 +460,11 @@ template<typename C,
          template<typename ...> class M, template<typename ...> class V>
 basic_value<C, M, V>& find(basic_value<C, M, V>& v, const key& ky)
 {
-    auto& tab = v.template cast<value_t::table>();
+    auto& tab = v.as_table();
     if(tab.count(ky) == 0)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[error] key \"", ky, "\" not found"), {
+            "key \"", ky, "\" not found"), {
                 {std::addressof(detail::get_region(v)), "in this table"}
             }));
     }
@@ -455,17 +472,63 @@ basic_value<C, M, V>& find(basic_value<C, M, V>& v, const key& ky)
 }
 template<typename C,
          template<typename ...> class M, template<typename ...> class V>
-basic_value<C, M, V>&& find(basic_value<C, M, V>&& v, const key& ky)
+basic_value<C, M, V> find(basic_value<C, M, V>&& v, const key& ky)
 {
-    auto& tab = v.template cast<value_t::table>();
+    typename basic_value<C, M, V>::table_type tab = std::move(v).as_table();
     if(tab.count(ky) == 0)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[error] key \"", ky, "\" not found"), {
+            "key \"", ky, "\" not found"), {
                 {std::addressof(detail::get_region(v)), "in this table"}
             }));
     }
-    return std::move(tab.at(ky));
+    return basic_value<C, M, V>(std::move(tab.at(ky)));
+}
+
+// ----------------------------------------------------------------------------
+// find(value, idx)
+template<typename C,
+         template<typename ...> class M, template<typename ...> class V>
+basic_value<C, M, V> const&
+find(const basic_value<C, M, V>& v, const std::size_t idx)
+{
+    const auto& ary = v.as_array();
+    if(ary.size() <= idx)
+    {
+        throw std::out_of_range(detail::format_underline(concat_to_string(
+            "index ", idx, " is out of range"), {
+                {std::addressof(detail::get_region(v)), "in this array"}
+            }));
+    }
+    return ary.at(idx);
+}
+template<typename C,
+         template<typename ...> class M, template<typename ...> class V>
+basic_value<C, M, V>& find(basic_value<C, M, V>& v, const std::size_t idx)
+{
+    auto& ary = v.as_array();
+    if(ary.size() <= idx)
+    {
+        throw std::out_of_range(detail::format_underline(concat_to_string(
+            "index ", idx, " is out of range"), {
+                {std::addressof(detail::get_region(v)), "in this array"}
+            }));
+    }
+    return ary.at(idx);
+}
+template<typename C,
+         template<typename ...> class M, template<typename ...> class V>
+basic_value<C, M, V> find(basic_value<C, M, V>&& v, const std::size_t idx)
+{
+    auto& ary = v.as_array();
+    if(ary.size() <= idx)
+    {
+        throw std::out_of_range(detail::format_underline(concat_to_string(
+            "index ", idx, " is out of range"), {
+                {std::addressof(detail::get_region(v)), "in this array"}
+            }));
+    }
+    return basic_value<C, M, V>(std::move(ary.at(idx)));
 }
 
 // ----------------------------------------------------------------------------
@@ -476,11 +539,11 @@ template<typename T, typename C,
 decltype(::toml::get<T>(std::declval<basic_value<C, M, V> const&>()))
 find(const basic_value<C, M, V>& v, const key& ky)
 {
-    const auto& tab = v.template cast<value_t::table>();
+    const auto& tab = v.as_table();
     if(tab.count(ky) == 0)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[error] key \"", ky, "\" not found"), {
+            "key \"", ky, "\" not found"), {
                 {std::addressof(detail::get_region(v)), "in this table"}
             }));
     }
@@ -492,11 +555,11 @@ template<typename T, typename C,
 decltype(::toml::get<T>(std::declval<basic_value<C, M, V>&>()))
 find(basic_value<C, M, V>& v, const key& ky)
 {
-    auto& tab = v.template cast<value_t::table>();
+    auto& tab = v.as_table();
     if(tab.count(ky) == 0)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[error] key \"", ky, "\" not found"), {
+            "key \"", ky, "\" not found"), {
                 {std::addressof(detail::get_region(v)), "in this table"}
             }));
     }
@@ -508,68 +571,163 @@ template<typename T, typename C,
 decltype(::toml::get<T>(std::declval<basic_value<C, M, V>&&>()))
 find(basic_value<C, M, V>&& v, const key& ky)
 {
-    auto& tab = v.template cast<value_t::table>();
+    typename basic_value<C, M, V>::table_type tab = std::move(v).as_table();
     if(tab.count(ky) == 0)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[error] key \"", ky, "\" not found"), {
+            "key \"", ky, "\" not found"), {
                 {std::addressof(detail::get_region(v)), "in this table"}
             }));
     }
     return ::toml::get<T>(std::move(tab.at(ky)));
 }
 
+// ----------------------------------------------------------------------------
+// find<T>(value, idx)
+template<typename T, typename C,
+         template<typename ...> class M, template<typename ...> class V>
+decltype(::toml::get<T>(std::declval<basic_value<C, M, V> const&>()))
+find(const basic_value<C, M, V>& v, const std::size_t idx)
+{
+    const auto& ary = v.as_array();
+    if(ary.size() <= idx)
+    {
+        throw std::out_of_range(detail::format_underline(concat_to_string(
+            "index ", idx, " is out of range"), {
+                {std::addressof(detail::get_region(v)), "in this array"}
+            }));
+    }
+    return ::toml::get<T>(ary.at(idx));
+}
+template<typename T, typename C,
+         template<typename ...> class M, template<typename ...> class V>
+decltype(::toml::get<T>(std::declval<basic_value<C, M, V>&>()))
+find(basic_value<C, M, V>& v, const std::size_t idx)
+{
+    auto& ary = v.as_array();
+    if(ary.size() <= idx)
+    {
+        throw std::out_of_range(detail::format_underline(concat_to_string(
+            "index ", idx, " is out of range"), {
+                {std::addressof(detail::get_region(v)), "in this array"}
+            }));
+    }
+    return ::toml::get<T>(ary.at(idx));
+}
+template<typename T, typename C,
+         template<typename ...> class M, template<typename ...> class V>
+decltype(::toml::get<T>(std::declval<basic_value<C, M, V>&&>()))
+find(basic_value<C, M, V>&& v, const std::size_t idx)
+{
+    typename basic_value<C, M, V>::array_type ary = std::move(v).as_array();
+    if(ary.size() <= idx)
+    {
+        throw std::out_of_range(detail::format_underline(concat_to_string(
+            "index ", idx, " is out of range"), {
+                {std::addressof(detail::get_region(v)), "in this array"}
+            }));
+    }
+    return ::toml::get<T>(std::move(ary.at(idx)));
+}
+
 // --------------------------------------------------------------------------
 // toml::find(toml::value, toml::key, Ts&& ... keys)
 
+namespace detail
+{
+// It suppresses warnings by -Wsign-conversion. Let's say we have the following
+// code.
+// ```cpp
+// const auto x = toml::find<std::string>(data, "array", 0);
+// ```
+// Here, the type of literal number `0` is `int`. `int` is a signed integer.
+// `toml::find` takes `std::size_t` as an index. So it causes implicit sign
+// conversion and `-Wsign-conversion` warns about it. Using `0u` instead of `0`
+// suppresses the warning, but it makes user code messy.
+//     To suppress this warning, we need to be aware of type conversion caused
+// by `toml::find(v, key1, key2, ... keys)`. But the thing is that the types of
+// keys can be any combination of {string-like, size_t-like}. Of course we can't
+// write down all the combinations. Thus we need to use some function that
+// recognize the type of argument and cast it into `std::string` or
+// `std::size_t` depending on the context.
+//     `key_cast` does the job. It has 2 overloads. One is invoked when the
+// argument type is an integer and cast the argument into `std::size_t`. The
+// other is invoked when the argument type is not an integer, possibly one of
+// std::string, const char[N] or const char*, and construct std::string from
+// the argument.
+//     `toml::find(v, k1, k2, ... ks)` uses `key_cast` before passing `ks` to
+// `toml::find(v, k)` to suppress -Wsign-conversion.
+
+template<typename T>
+enable_if_t<conjunction<std::is_integral<remove_cvref_t<T>>,
+            negation<std::is_same<remove_cvref_t<T>, bool>>>::value, std::size_t>
+key_cast(T&& v) noexcept
+{
+    return std::size_t(v);
+}
+template<typename T>
+enable_if_t<negation<conjunction<std::is_integral<remove_cvref_t<T>>,
+            negation<std::is_same<remove_cvref_t<T>, bool>>>>::value, std::string>
+key_cast(T&& v) noexcept
+{
+    return std::string(std::forward<T>(v));
+}
+} // detail
+
 template<typename C,
          template<typename ...> class M, template<typename ...> class V,
-         typename ... Ts>
+         typename Key1, typename Key2, typename ... Keys>
 const basic_value<C, M, V>&
-find(const basic_value<C, M, V>& v, const ::toml::key& ky, Ts&& ... keys)
+find(const basic_value<C, M, V>& v, Key1&& k1, Key2&& k2, Keys&& ... keys)
 {
-    return ::toml::find(::toml::find(v, ky), std::forward<Ts>(keys)...);
+    return ::toml::find(::toml::find(v, detail::key_cast(k1)),
+            detail::key_cast(k2), std::forward<Keys>(keys)...);
 }
 template<typename C,
          template<typename ...> class M, template<typename ...> class V,
-         typename ... Ts>
+         typename Key1, typename Key2, typename ... Keys>
 basic_value<C, M, V>&
-find(basic_value<C, M, V>& v, const ::toml::key& ky, Ts&& ... keys)
+find(basic_value<C, M, V>& v, Key1&& k1, Key2&& k2, Keys&& ... keys)
 {
-    return ::toml::find(::toml::find(v, ky), std::forward<Ts>(keys)...);
+    return ::toml::find(::toml::find(v, detail::key_cast(k1)),
+            detail::key_cast(k2), std::forward<Keys>(keys)...);
 }
 template<typename C,
          template<typename ...> class M, template<typename ...> class V,
-         typename ... Ts>
+         typename Key1, typename Key2, typename ... Keys>
-basic_value<C, M, V>&&
+basic_value<C, M, V>
-find(basic_value<C, M, V>&& v, const ::toml::key& ky, Ts&& ... keys)
+find(basic_value<C, M, V>&& v, Key1&& k1, Key2&& k2, Keys&& ... keys)
 {
-    return ::toml::find(::toml::find(std::move(v), ky), std::forward<Ts>(keys)...);
+    return ::toml::find(::toml::find(std::move(v), std::forward<Key1>(k1)),
+            detail::key_cast(k2), std::forward<Keys>(keys)...);
 }
 
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V,
-         typename ... Ts>
+         typename Key1, typename Key2, typename ... Keys>
 decltype(::toml::get<T>(std::declval<const basic_value<C, M, V>&>()))
-find(const basic_value<C, M, V>& v, const ::toml::key& ky, Ts&& ... keys)
+find(const basic_value<C, M, V>& v, Key1&& k1, Key2&& k2, Keys&& ... keys)
 {
-    return ::toml::find<T>(::toml::find(v, ky), std::forward<Ts>(keys)...);
+    return ::toml::find<T>(::toml::find(v, detail::key_cast(k1)),
+            detail::key_cast(k2), std::forward<Keys>(keys)...);
 }
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V,
-         typename ... Ts>
+         typename Key1, typename Key2, typename ... Keys>
 decltype(::toml::get<T>(std::declval<basic_value<C, M, V>&>()))
-find(basic_value<C, M, V>& v, const ::toml::key& ky, Ts&& ... keys)
+find(basic_value<C, M, V>& v, Key1&& k1, Key2&& k2, Keys&& ... keys)
 {
-    return ::toml::find<T>(::toml::find(v, ky), std::forward<Ts>(keys)...);
+    return ::toml::find<T>(::toml::find(v, detail::key_cast(k1)),
+            detail::key_cast(k2), std::forward<Keys>(keys)...);
 }
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V,
-         typename ... Ts>
+         typename Key1, typename Key2, typename ... Keys>
 decltype(::toml::get<T>(std::declval<basic_value<C, M, V>&&>()))
-find(basic_value<C, M, V>&& v, const ::toml::key& ky, Ts&& ... keys)
+find(basic_value<C, M, V>&& v, Key1&& k1, Key2&& k2, Keys&& ... keys)
 {
-    return ::toml::find<T>(::toml::find(std::move(v), ky), std::forward<Ts>(keys)...);
+    return ::toml::find<T>(::toml::find(std::move(v), detail::key_cast(k1)),
+            detail::key_cast(k2), std::forward<Keys>(keys)...);
 }
 
 // ============================================================================
@@ -608,8 +766,7 @@ get_or(const basic_value<C, M, V>& v, const T& opt)
 {
     try
     {
-        return get<typename std::remove_cv<
+        return get<detail::remove_cvref_t<T>>(v);
-            typename std::remove_reference<T>::type>::type>(v);
     }
     catch(...)
     {
@@ -624,8 +781,7 @@ get_or(basic_value<C, M, V>& v, T& opt)
 {
     try
     {
-        return get<typename std::remove_cv<
+        return get<detail::remove_cvref_t<T>>(v);
-            typename std::remove_reference<T>::type>::type>(v);
     }
     catch(...)
     {
@@ -634,18 +790,17 @@ get_or(basic_value<C, M, V>& v, T& opt)
 }
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V>
-detail::enable_if_t<
+detail::enable_if_t<detail::is_exact_toml_type<detail::remove_cvref_t<T>,
-    detail::is_exact_toml_type<T, basic_value<C, M, V>>::value, T>&&
+    basic_value<C, M, V>>::value, detail::remove_cvref_t<T>>
 get_or(basic_value<C, M, V>&& v, T&& opt)
 {
     try
     {
-        return get<typename std::remove_cv<
+        return get<detail::remove_cvref_t<T>>(std::move(v));
-            typename std::remove_reference<T>::type>::type>(v);
     }
     catch(...)
     {
-        return opt;
+        return detail::remove_cvref_t<T>(std::forward<T>(opt));
     }
 }
 
@@ -654,14 +809,13 @@ get_or(basic_value<C, M, V>&& v, T&& opt)
 
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V>
-detail::enable_if_t<std::is_same<
+detail::enable_if_t<std::is_same<detail::remove_cvref_t<T>, std::string>::value,
-    typename std::remove_cv<typename std::remove_reference<T>::type>::type,
+    std::string> const&
-    std::string>::value, std::string> const&
+get_or(const basic_value<C, M, V>& v, const T& opt)
-get_or(const basic_value<C, M, V>& v, T&& opt)
 {
     try
     {
-        return v.template cast<value_t::string>().str;
+        return v.as_string().str;
     }
     catch(...)
     {
@@ -675,7 +829,7 @@ get_or(basic_value<C, M, V>& v, T& opt)
 {
     try
     {
-        return v.template cast<value_t::string>().str;
+        return v.as_string().str;
     }
     catch(...)
     {
@@ -684,18 +838,17 @@ get_or(basic_value<C, M, V>& v, T& opt)
 }
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V>
-detail::enable_if_t<std::is_same<
+detail::enable_if_t<
-    typename std::remove_cv<typename std::remove_reference<T>::type>::type,
+    std::is_same<detail::remove_cvref_t<T>, std::string>::value, std::string>
-    std::string>::value, std::string>
 get_or(basic_value<C, M, V>&& v, T&& opt)
 {
     try
     {
-        return std::move(v.template cast<value_t::string>().str);
+        return std::move(v.as_string().str);
     }
     catch(...)
     {
-        return std::forward<T>(opt);
+        return std::string(std::forward<T>(opt));
     }
 }
 
@@ -710,11 +863,11 @@ get_or(const basic_value<C, M, V>& v, T&& opt)
 {
     try
     {
-        return std::move(v.template cast<value_t::string>().str);
+        return std::move(v.as_string().str);
     }
     catch(...)
     {
-        return std::string(opt);
+        return std::string(std::forward<T>(opt));
     }
 }
 
@@ -724,24 +877,21 @@ get_or(const basic_value<C, M, V>& v, T&& opt)
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V>
 detail::enable_if_t<detail::conjunction<
-    detail::negation<detail::is_exact_toml_type<
+    detail::negation<detail::is_exact_toml_type<detail::remove_cvref_t<T>,
-        typename std::remove_cv<typename std::remove_reference<T>::type>::type,
         basic_value<C, M, V>>>,
-    detail::negation<std::is_same<std::string,
+    detail::negation<std::is_same<std::string, detail::remove_cvref_t<T>>>,
-        typename std::remove_cv<typename std::remove_reference<T>::type>::type>>,
     detail::negation<detail::is_string_literal<
         typename std::remove_reference<T>::type>>
-    >::value, typename std::remove_reference<T>::type>
+    >::value, detail::remove_cvref_t<T>>
 get_or(const basic_value<C, M, V>& v, T&& opt)
 {
     try
     {
-        return get<typename std::remove_cv<
+        return get<detail::remove_cvref_t<T>>(v);
-            typename std::remove_reference<T>::type>::type>(v);
     }
     catch(...)
     {
-        return std::forward<T>(opt);
+        return detail::remove_cvref_t<T>(std::forward<T>(opt));
     }
 }
 
@@ -768,7 +918,7 @@ find_or(basic_value<C, M, V>& v, const toml::key& ky, basic_value<C, M, V>& opt)
     if(!v.is_table()) {return opt;}
     auto& tab = v.as_table();
     if(tab.count(ky) == 0) {return opt;}
-    return tab[ky];
+    return tab.at(ky);
 }
 
 template<typename C,
@@ -779,7 +929,7 @@ find_or(basic_value<C, M, V>&& v, const toml::key& ky, basic_value<C, M, V>&& op
     if(!v.is_table()) {return opt;}
     auto tab = std::move(v).as_table();
     if(tab.count(ky) == 0) {return opt;}
-    return std::move(tab[ky]);
+    return basic_value<C, M, V>(std::move(tab.at(ky)));
 }
 
 // ---------------------------------------------------------------------------
@@ -805,19 +955,20 @@ find_or(basic_value<C, M, V>& v, const toml::key& ky, T& opt)
     if(!v.is_table()) {return opt;}
     auto& tab = v.as_table();
     if(tab.count(ky) == 0) {return opt;}
-    return get_or(tab[ky], opt);
+    return get_or(tab.at(ky), opt);
 }
 
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V>
 detail::enable_if_t<
-    detail::is_exact_toml_type<T, basic_value<C, M, V>>::value, T>&&
+    detail::is_exact_toml_type<T, basic_value<C, M, V>>::value,
+    detail::remove_cvref_t<T>>
 find_or(basic_value<C, M, V>&& v, const toml::key& ky, T&& opt)
 {
-    if(!v.is_table()) {return opt;}
+    if(!v.is_table()) {return std::forward<T>(opt);}
     auto tab = std::move(v).as_table();
-    if(tab.count(ky) == 0) {return opt;}
+    if(tab.count(ky) == 0) {return std::forward<T>(opt);}
-    return get_or(std::move(tab[ky]), std::forward<T>(opt));
+    return get_or(std::move(tab.at(ky)), std::forward<T>(opt));
 }
 
 // ---------------------------------------------------------------------------
@@ -863,7 +1014,7 @@ detail::enable_if_t<
     std::string>
 find_or(const basic_value<C, M, V>& v, const toml::key& ky, T&& opt)
 {
-    if(!v.is_table()) {return opt;}
+    if(!v.is_table()) {return std::string(opt);}
     const auto& tab = v.as_table();
     if(tab.count(ky) == 0) {return std::string(opt);}
     return get_or(tab.at(ky), std::forward<T>(opt));
@@ -874,19 +1025,20 @@ find_or(const basic_value<C, M, V>& v, const toml::key& ky, T&& opt)
 template<typename T, typename C,
          template<typename ...> class M, template<typename ...> class V>
 detail::enable_if_t<detail::conjunction<
+    // T is not an exact toml type
     detail::negation<detail::is_exact_toml_type<
-        typename std::remove_cv<typename std::remove_reference<T>::type>::type,
+        detail::remove_cvref_t<T>, basic_value<C, M, V>>>,
-        basic_value<C, M, V>>>,
+    // T is not std::string
-    detail::negation<std::is_same<std::string,
+    detail::negation<std::is_same<std::string, detail::remove_cvref_t<T>>>,
-        typename std::remove_cv<typename std::remove_reference<T>::type>::type>>,
+    // T is not a string literal
     detail::negation<detail::is_string_literal<
         typename std::remove_reference<T>::type>>
-    >::value, T>
+    >::value, detail::remove_cvref_t<T>>
 find_or(const basic_value<C, M, V>& v, const toml::key& ky, T&& opt)
 {
-    if(!v.is_table()) {return opt;}
+    if(!v.is_table()) {return std::forward<T>(opt);}
     const auto& tab = v.as_table();
-    if(tab.count(ky) == 0) {return opt;}
+    if(tab.count(ky) == 0) {return std::forward<T>(opt);}
     return get_or(tab.at(ky), std::forward<T>(opt));
 }
 
@@ -920,21 +1072,6 @@ expect(const basic_value<C, M, V>& v, const toml::key& k) noexcept
         return err(e.what());
     }
 }
-template<typename T, typename Table>
+
-detail::enable_if_t<detail::conjunction<
-    detail::is_map<Table>, detail::is_basic_value<typename Table::mapped_type>
-    >::value, result<T, std::string>>
-expect(const Table& t, const toml::key& k,
-       std::string tablename = "unknown table") noexcept
-{
-    try
-    {
-        return ok(find<T>(t, k, std::move(tablename)));
-    }
-    catch(const std::exception& e)
-    {
-        return err(e.what());
-    }
-}
 } // toml
 #endif// TOML11_GET

toml/lexer.hpp

@@ -63,12 +63,22 @@ using lex_integer = either<lex_bin_int, lex_oct_int, lex_hex_int, lex_dec_int>;
 using lex_inf = sequence<character<'i'>, character<'n'>, character<'f'>>;
 using lex_nan = sequence<character<'n'>, character<'a'>, character<'n'>>;
 using lex_special_float = sequence<maybe<lex_sign>, either<lex_inf, lex_nan>>;
-using lex_exponent_part = sequence<either<character<'e'>, character<'E'>>, lex_dec_int>;
 
 using lex_zero_prefixable_int = sequence<lex_digit, repeat<either<lex_digit,
     sequence<lex_underscore, lex_digit>>, unlimited>>;
+
 using lex_fractional_part = sequence<character<'.'>, lex_zero_prefixable_int>;
 
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+// use toml-lang/toml HEAD
+using lex_exponent_part   = sequence<either<character<'e'>, character<'E'>>,
+        maybe<lex_sign>, lex_zero_prefixable_int>;
+#else
+// strictly TOML v0.5.0
+using lex_exponent_part = sequence<either<character<'e'>, character<'E'>>,
+        lex_dec_int>;
+#endif
+
 using lex_float = either<lex_special_float,
       sequence<lex_dec_int, either<lex_exponent_part,
       sequence<lex_fractional_part, maybe<lex_exponent_part>>>>>;
@@ -115,9 +125,17 @@ using lex_local_time       = lex_partial_time;
 // ===========================================================================
 
 using lex_quotation_mark  = character<'"'>;
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+using lex_basic_unescaped = exclude<either<in_range<0x00, 0x08>, // 0x09 (tab)
+                                           in_range<0x0a, 0x1F>, // is allowed
+                                           character<0x22>, character<0x5C>,
+                                           character<0x7F>>>;
+#else
 using lex_basic_unescaped = exclude<either<in_range<0x00, 0x1F>,
                                            character<0x22>, character<0x5C>,
                                            character<0x7F>>>;
+
+#endif
 using lex_escape          = character<'\\'>;
 using lex_escape_unicode_short = sequence<character<'u'>,
                                           repeat<lex_hex_dig, exactly<4>>>;
@@ -137,10 +155,18 @@ using lex_basic_string = sequence<lex_quotation_mark,
                                   lex_quotation_mark>;
 
 using lex_ml_basic_string_delim = repeat<lex_quotation_mark, exactly<3>>;
-using lex_ml_basic_unescaped    = exclude<either<in_range<0x00, 0x1F>,
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
+using lex_ml_basic_unescaped    = exclude<either<in_range<0x00, 0x08>, // 0x09
+                                                 in_range<0x0a, 0x1F>, // is tab
                                                  character<0x5C>,
                                                  character<0x7F>,
                                                  lex_ml_basic_string_delim>>;
+#else // TOML v0.5.0
+using lex_ml_basic_unescaped    = exclude<either<in_range<0x00,0x1F>,
+                                                 character<0x5C>,
+                                                 character<0x7F>,
+                                                 lex_ml_basic_string_delim>>;
+#endif
 
 using lex_ml_basic_escaped_newline = sequence<
         lex_escape, maybe<lex_ws>, lex_newline,

toml/literal.hpp

@@ -76,7 +76,8 @@ inline ::toml::value operator"" _toml(const char* str, std::size_t len)
     }
     else // none of them.
     {
-        throw ::toml::syntax_error(data.unwrap_err());
+        throw ::toml::syntax_error(data.unwrap_err(),
+                                   source_location(std::addressof(loc)));
     }
 }
 

toml/region.hpp

@@ -2,7 +2,6 @@
 // Distributed under the MIT License.
 #ifndef TOML11_REGION_HPP
 #define TOML11_REGION_HPP
-#include "exception.hpp"
 #include <memory>
 #include <vector>
 #include <algorithm>
@@ -10,6 +9,7 @@
 #include <iterator>
 #include <iomanip>
 #include <cassert>
+#include "color.hpp"
 
 namespace toml
 {
@@ -41,6 +41,7 @@ struct region_base
     region_base& operator=(region_base&&     ) = default;
 
     virtual bool is_ok()           const noexcept {return false;}
+    virtual char front()           const noexcept {return '\0';}
 
     virtual std::string str()      const {return std::string("unknown region");}
     virtual std::string name()     const {return std::string("unknown file");}
@@ -89,6 +90,7 @@ struct location final : public region_base
     ~location() = default;
 
     bool is_ok() const noexcept override {return static_cast<bool>(source_);}
+    char front() const noexcept override {return *iter_;}
 
     // this const prohibits codes like `++(loc.iter())`.
     const const_iterator iter()  const noexcept {return iter_;}
@@ -231,16 +233,16 @@ struct region final : public region_base
 
     region& operator+=(const region& other)
     {
-        if(this->begin() != other.begin() || this->end() != other.end() ||
+        // different regions cannot be concatenated
-           this->last_  != other.first_)
+        assert(this->begin() == other.begin() && this->end() == other.end() &&
-        {
+               this->last_   == other.first_);
-            throw internal_error("invalid region concatenation");
+
-        }
         this->last_ = other.last_;
         return *this;
     }
 
     bool is_ok() const noexcept override {return static_cast<bool>(source_);}
+    char front() const noexcept override {return *first_;}
 
     std::string str()  const override {return make_string(first_, last_);}
     std::string line() const override
@@ -420,7 +422,8 @@ struct region final : public region_base
 // to show a better error message.
 inline std::string format_underline(const std::string& message,
         const std::vector<std::pair<region_base const*, std::string>>& reg_com,
-        const std::vector<std::string>& helps = {})
+        const std::vector<std::string>& helps = {},
+        const bool colorize = TOML11_ERROR_MESSAGE_COLORIZED)
 {
     assert(!reg_com.empty());
 
@@ -434,7 +437,27 @@ inline std::string format_underline(const std::string& message,
     )->first->line_num().size());
 
     std::ostringstream retval;
-    retval << message << '\n';
+
+    if(colorize)
+    {
+        retval << color::colorize; // turn on ANSI color
+    }
+
+    // XXX
+    // Here, before `colorize` support, it does not output `[error]` prefix
+    // automatically. So some user may output it manually and this change may
+    // duplicate the prefix. To avoid it, check the first 7 characters and
+    // if it is "[error]", it removes that part from the message shown.
+    if(message.size() > 7 && message.substr(0, 7) == "[error]")
+    {
+        retval << color::bold << color::red << "[error]" << color::reset
+               << color::bold << message.substr(7) << color::reset << '\n';
+    }
+    else
+    {
+        retval << color::bold << color::red << "[error] " << color::reset
+               << color::bold << message << color::reset << '\n';
+    }
 
     for(auto iter = reg_com.begin(); iter != reg_com.end(); ++iter)
     {
@@ -442,34 +465,42 @@ inline std::string format_underline(const std::string& message,
         if(iter != reg_com.begin() &&
            std::prev(iter)->first->name() == iter->first->name())
         {
-            retval << "\n ...\n";
+            retval << color::bold << color::blue << "\n ...\n" << color::reset;
         }
         else // if filename differs, print " --> filename.toml"
         {
             if(iter != reg_com.begin()) {retval << '\n';}
-            retval << " --> " << iter->first->name() << '\n';
+            retval << color::bold << color::blue << " --> " << color::reset
+                   << iter->first->name() << '\n';
+            // add one almost-empty line for readability
+            retval << make_string(static_cast<std::size_t>(line_num_width + 1), ' ')
+                   << color::bold << color::blue << " | "  << color::reset << '\n';
         }
         const region_base* const reg = iter->first;
         const std::string&   comment = iter->second;
 
-        retval << ' ' << std::setw(line_num_width) << reg->line_num();
+        retval << ' ' << color::bold << color::blue << std::setw(line_num_width)
-        retval << " | " << reg->line() << '\n';
+               << std::right << reg->line_num() << " | "  << color::reset
-        retval << make_string(static_cast<std::size_t>(line_num_width + 1), ' ');
+               << reg->line() << '\n';
-        retval << " | " << make_string(reg->before(), ' ');
+
+        retval << make_string(static_cast<std::size_t>(line_num_width + 1), ' ')
+               << color::bold << color::blue << " | " << color::reset
+               << make_string(reg->before(), ' ');
 
         if(reg->size() == 1)
         {
             // invalid
             // ^------
-            retval << '^';
+            retval << color::bold << color::red
-            retval << make_string(reg->after(), '-');
+                   << '^' << make_string(reg->after(), '-') << color::reset;
         }
         else
         {
             // invalid
             // ~~~~~~~
             const auto underline_len = std::min(reg->size(), reg->line().size());
-            retval << make_string(underline_len, '~');
+            retval << color::bold << color::red
+                   << make_string(underline_len, '~') << color::reset;
         }
         retval << ' ';
         retval << comment;
@@ -479,10 +510,10 @@ inline std::string format_underline(const std::string& message,
     {
         retval << '\n';
         retval << make_string(static_cast<std::size_t>(line_num_width + 1), ' ');
-        retval << " | ";
+        retval << color::bold << color::blue << " | " << color::reset;
         for(const auto help : helps)
         {
-            retval << "\nHint: ";
+            retval << color::bold << "\nHint: " << color::reset;
             retval << help;
         }
     }

toml/serializer.hpp

@@ -118,8 +118,14 @@ struct serializer
         {
             return token; // there is no exponent part. just return it.
         }
-
+#ifdef TOML11_USE_UNRELEASED_TOML_FEATURES
-        // zero-prefix in an exponent is NOT allowed in TOML.
+        // Although currently it is not released yet, TOML will allow
+        // zero-prefix in an exponent part such as 1.234e+01.
+        // The following code removes the zero prefixes.
+        // If the feature is activated, the following codes can be skipped.
+        return token;
+#endif
+        // zero-prefix in an exponent is NOT allowed in TOML v0.5.0.
         // remove it if it exists.
         bool        sign_exists = false;
         std::size_t zero_prefix = 0;

toml/source_location.hpp

@@ -48,7 +48,11 @@ struct source_location
     {
         if(reg)
         {
-            line_num_    = static_cast<std::uint_least32_t>(std::stoul(reg->line_num()));
+            if(reg->line_num() != detail::region_base().line_num())
+            {
+                line_num_ = static_cast<std::uint_least32_t>(
+                        std::stoul(reg->line_num()));
+            }
             column_num_  = static_cast<std::uint_least32_t>(reg->before() + 1);
             region_size_ = static_cast<std::uint_least32_t>(reg->size());
             file_name_   = reg->name();

toml/storage.hpp

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

toml/string.hpp

@@ -2,6 +2,7 @@
 // Distributed under the MIT License.
 #ifndef TOML11_STRING_HPP
 #define TOML11_STRING_HPP
+#include <algorithm>
 #include <string>
 #include <cstdint>
 #if __cplusplus >= 201703L
@@ -45,6 +46,11 @@ struct string
     operator std::string const& () const& noexcept {return str;}
     operator std::string&&      () &&     noexcept {return std::move(str);}
 
+    string& operator+=(const char*        rhs) {str += rhs; return *this;}
+    string& operator+=(const char         rhs) {str += rhs; return *this;}
+    string& operator+=(const std::string& rhs) {str += rhs; return *this;}
+    string& operator+=(const string&      rhs) {str += rhs.str; return *this;}
+
 #if __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){}
@@ -54,6 +60,8 @@ struct string
 
     explicit operator std::string_view() const noexcept
     {return std::string_view(str);}
+
+    string& operator+=(const std::string_view& rhs) {str += rhs; return *this;}
 #endif
 
     string_t    kind;

toml/traits.hpp

@@ -105,12 +105,20 @@ struct has_into_toml_method
 : decltype(has_into_toml_method_impl::check<T>(nullptr)){};
 
 #ifdef __INTEL_COMPILER
-#undef decltype(...)
+#undef decltype
 #endif
 
 // ---------------------------------------------------------------------------
 // C++17 and/or/not
 
+#if __cplusplus >= 201703L
+
+using std::conjunction;
+using std::disjunction;
+using std::negation;
+
+#else
+
 template<typename ...> struct conjunction : std::true_type{};
 template<typename T>   struct conjunction<T> : T{};
 template<typename T, typename ... Ts>
@@ -128,6 +136,8 @@ struct disjunction<T, Ts...> :
 template<typename T>
 struct negation : std::integral_constant<bool, !static_cast<bool>(T::value)>{};
 
+#endif
+
 // ---------------------------------------------------------------------------
 // type checkers
 
@@ -182,6 +192,13 @@ struct is_basic_value<::toml::basic_value<C, M, V>>: std::true_type{};
 // ---------------------------------------------------------------------------
 // C++14 index_sequence
 
+#if __cplusplus >= 201402L
+
+using std::index_sequence;
+using std::make_index_sequence;
+
+#else
+
 template<std::size_t ... Ns> struct index_sequence{};
 
 template<typename IS, std::size_t N> struct push_back_index_sequence{};
@@ -205,11 +222,22 @@ struct index_sequence_maker<0>
 template<std::size_t N>
 using make_index_sequence = typename index_sequence_maker<N-1>::type;
 
+#endif // __cplusplus >= 2014
+
 // ---------------------------------------------------------------------------
 // C++14 enable_if_t
+
+#if __cplusplus >= 201402L
+
+using std::enable_if_t;
+
+#else
+
 template<bool B, typename T>
 using enable_if_t = typename std::enable_if<B, T>::type;
 
+#endif // __cplusplus >= 2014
+
 // ---------------------------------------------------------------------------
 // return_type_of_t
 
@@ -240,6 +268,19 @@ disjunction<
         >
     >{};
 
+// ---------------------------------------------------------------------------
+// C++20 remove_cvref_t
+
+template<typename T>
+struct remove_cvref
+{
+    using type = typename std::remove_cv<
+        typename std::remove_reference<T>::type>::type;
+};
+
+template<typename T>
+using remove_cvref_t = typename remove_cvref<T>::type;
+
 }// detail
 }//toml
 #endif // TOML_TRAITS

toml/utility.hpp

@@ -20,12 +20,20 @@
 namespace toml
 {
 
+#if __cplusplus >= 201402L
+
+using std::make_unique;
+
+#else
+
 template<typename T, typename ... Ts>
 inline std::unique_ptr<T> make_unique(Ts&& ... args)
 {
     return std::unique_ptr<T>(new T(std::forward<Ts>(args)...));
 }
 
+#endif // __cplusplus >= 2014
+
 namespace detail
 {
 
@@ -76,10 +84,10 @@ std::string concat_to_string(Ts&& ... args)
     return detail::concat_to_string_impl(oss, std::forward<Ts>(args) ...);
 }
 
-template<typename T, typename U>
+template<typename T>
-T from_string(const std::string& str, U&& opt)
+T from_string(const std::string& str, T opt)
 {
-    T v(static_cast<T>(std::forward<U>(opt)));
+    T v(opt);
     std::istringstream iss(str);
     iss >> v;
     return v;

toml/value.hpp

@@ -32,10 +32,10 @@ template<value_t Expected,
 throw_bad_cast(value_t actual, const ::toml::basic_value<C, T, A>& v)
 {
     throw type_error(detail::format_underline(concat_to_string(
-        "[error] toml::value bad_cast to ", Expected), {
+        "toml::value: bad_cast to ", Expected), {
             {std::addressof(get_region(v)),
              concat_to_string("the actual type is ", actual)}
-        }));
+        }), v.location());
 }
 
 // switch by `value_t` and call the corresponding `value::as_xxx()`. {{{
@@ -529,14 +529,6 @@ class basic_value
         assigner(this->boolean_, b);
         return *this;
     }
-    template<typename Container>
-    basic_value(boolean b, detail::region<Container> reg)
-        : type_(value_t::boolean),
-          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
-          comments_(region_info_->comments())
-    {
-        assigner(this->boolean_, b);
-    }
     basic_value(boolean b, std::vector<std::string> comments)
         : type_(value_t::boolean),
           region_info_(std::make_shared<region_base>(region_base{})),
@@ -557,19 +549,6 @@ class basic_value
         assigner(this->integer_, static_cast<integer>(i));
     }
 
-    template<typename T, typename Container, typename std::enable_if<
-        detail::conjunction<
-            std::is_integral<T>,
-            detail::negation<std::is_same<T, boolean>>
-        >::value, std::nullptr_t>::type = nullptr>
-    basic_value(T i, detail::region<Container> reg)
-        : type_(value_t::integer),
-          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
-          comments_(region_info_->comments())
-    {
-        assigner(this->integer_, static_cast<integer>(i));
-    }
-
     template<typename T, typename std::enable_if<detail::conjunction<
         std::is_integral<T>, detail::negation<std::is_same<T, boolean>>>::value,
         std::nullptr_t>::type = nullptr>
@@ -604,15 +583,6 @@ class basic_value
         assigner(this->floating_, static_cast<floating>(f));
     }
 
-    template<typename T, typename Container, typename std::enable_if<
-        std::is_floating_point<T>::value, std::nullptr_t>::type = nullptr>
-    basic_value(T f, detail::region<Container> reg)
-        : type_(value_t::floating),
-          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
-          comments_(region_info_->comments())
-    {
-        assigner(this->floating_, static_cast<floating>(f));
-    }
 
     template<typename T, typename std::enable_if<
         std::is_floating_point<T>::value, std::nullptr_t>::type = nullptr>
@@ -643,14 +613,6 @@ class basic_value
     {
         assigner(this->string_, std::move(s));
     }
-    template<typename Container>
-    basic_value(toml::string s, detail::region<Container> reg)
-        : type_(value_t::string),
-          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
-          comments_(region_info_->comments())
-    {
-        assigner(this->string_, std::move(s));
-    }
     basic_value& operator=(toml::string s)
     {
         this->cleanup();
@@ -782,14 +744,6 @@ class basic_value
     {
         assigner(this->local_date_, ld);
     }
-    template<typename Container>
-    basic_value(const local_date& ld, detail::region<Container> reg)
-        : type_(value_t::local_date),
-          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
-          comments_(region_info_->comments())
-    {
-        assigner(this->local_date_, ld);
-    }
     basic_value& operator=(const local_date& ld)
     {
         this->cleanup();
@@ -814,14 +768,6 @@ class basic_value
     {
         assigner(this->local_time_, lt);
     }
-    template<typename Container>
-    basic_value(const local_time& lt, detail::region<Container> reg)
-        : type_(value_t::local_time),
-          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
-          comments_(region_info_->comments())
-    {
-        assigner(this->local_time_, lt);
-    }
     basic_value(const local_time& lt, std::vector<std::string> comments)
         : type_(value_t::local_time),
           region_info_(std::make_shared<region_base>(region_base{})),
@@ -872,14 +818,6 @@ class basic_value
     {
         assigner(this->local_datetime_, ldt);
     }
-    template<typename Container>
-    basic_value(const local_datetime& ldt, detail::region<Container> reg)
-        : type_(value_t::local_datetime),
-          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
-          comments_(region_info_->comments())
-    {
-        assigner(this->local_datetime_, ldt);
-    }
     basic_value(const local_datetime& ldt, std::vector<std::string> comments)
         : type_(value_t::local_datetime),
           region_info_(std::make_shared<region_base>(region_base{})),
@@ -904,14 +842,6 @@ class basic_value
     {
         assigner(this->offset_datetime_, odt);
     }
-    template<typename Container>
-    basic_value(const offset_datetime& odt, detail::region<Container> reg)
-        : type_(value_t::offset_datetime),
-          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
-          comments_(region_info_->comments())
-    {
-        assigner(this->offset_datetime_, odt);
-    }
     basic_value(const offset_datetime& odt, std::vector<std::string> comments)
         : type_(value_t::offset_datetime),
           region_info_(std::make_shared<region_base>(region_base{})),
@@ -958,14 +888,6 @@ class basic_value
     {
         assigner(this->array_, ary);
     }
-    template<typename Container>
-    basic_value(const array_type& ary, detail::region<Container> reg)
-        : type_(value_t::array),
-          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
-          comments_(region_info_->comments())
-    {
-        assigner(this->array_, ary);
-    }
     basic_value(const array_type& ary, std::vector<std::string> comments)
         : type_(value_t::array),
           region_info_(std::make_shared<region_base>(region_base{})),
@@ -1079,14 +1001,6 @@ class basic_value
     {
         assigner(this->table_, tab);
     }
-    template<typename Container>
-    basic_value(const table_type& tab, detail::region<Container> reg)
-        : type_(value_t::table),
-          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
-          comments_(region_info_->comments())
-    {
-        assigner(this->table_, tab);
-    }
     basic_value(const table_type& tab, std::vector<std::string> comments)
         : type_(value_t::table),
           region_info_(std::make_shared<region_base>(region_base{})),
@@ -1216,6 +1130,93 @@ class basic_value
     }
 
     // for internal use ------------------------------------------------------
+    //
+    // Those constructors take detail::region that contains parse result.
+
+    template<typename Container>
+    basic_value(boolean b, detail::region<Container> reg)
+        : type_(value_t::boolean),
+          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
+          comments_(region_info_->comments())
+    {
+        assigner(this->boolean_, b);
+    }
+    template<typename T, typename Container, typename std::enable_if<
+        detail::conjunction<
+            std::is_integral<T>, detail::negation<std::is_same<T, boolean>>
+        >::value, std::nullptr_t>::type = nullptr>
+    basic_value(T i, detail::region<Container> reg)
+        : type_(value_t::integer),
+          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
+          comments_(region_info_->comments())
+    {
+        assigner(this->integer_, static_cast<integer>(i));
+    }
+    template<typename T, typename Container, typename std::enable_if<
+        std::is_floating_point<T>::value, std::nullptr_t>::type = nullptr>
+    basic_value(T f, detail::region<Container> reg)
+        : type_(value_t::floating),
+          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
+          comments_(region_info_->comments())
+    {
+        assigner(this->floating_, static_cast<floating>(f));
+    }
+    template<typename Container>
+    basic_value(toml::string s, detail::region<Container> reg)
+        : type_(value_t::string),
+          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
+          comments_(region_info_->comments())
+    {
+        assigner(this->string_, std::move(s));
+    }
+    template<typename Container>
+    basic_value(const local_date& ld, detail::region<Container> reg)
+        : type_(value_t::local_date),
+          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
+          comments_(region_info_->comments())
+    {
+        assigner(this->local_date_, ld);
+    }
+    template<typename Container>
+    basic_value(const local_time& lt, detail::region<Container> reg)
+        : type_(value_t::local_time),
+          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
+          comments_(region_info_->comments())
+    {
+        assigner(this->local_time_, lt);
+    }
+    template<typename Container>
+    basic_value(const local_datetime& ldt, detail::region<Container> reg)
+        : type_(value_t::local_datetime),
+          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
+          comments_(region_info_->comments())
+    {
+        assigner(this->local_datetime_, ldt);
+    }
+    template<typename Container>
+    basic_value(const offset_datetime& odt, detail::region<Container> reg)
+        : type_(value_t::offset_datetime),
+          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
+          comments_(region_info_->comments())
+    {
+        assigner(this->offset_datetime_, odt);
+    }
+    template<typename Container>
+    basic_value(const array_type& ary, detail::region<Container> reg)
+        : type_(value_t::array),
+          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
+          comments_(region_info_->comments())
+    {
+        assigner(this->array_, ary);
+    }
+    template<typename Container>
+    basic_value(const table_type& tab, detail::region<Container> reg)
+        : type_(value_t::table),
+          region_info_(std::make_shared<detail::region<Container>>(std::move(reg))),
+          comments_(region_info_->comments())
+    {
+        assigner(this->table_, tab);
+    }
 
     template<typename T, typename Container, typename std::enable_if<
         detail::is_exact_toml_type<T, value_type>::value,
@@ -1247,7 +1248,7 @@ class basic_value
     bool is_array()           const noexcept {return this->is(value_t::array          );}
     bool is_table()           const noexcept {return this->is(value_t::table          );}
 
-    value_t type() const {return type_;}
+    value_t type() const noexcept {return type_;}
 
     template<value_t T>
     typename detail::enum_to_type<T, value_type>::type&       cast() &
@@ -1567,6 +1568,140 @@ class basic_value
         return std::move(this->table_.value());
     }
 
+    // accessors =============================================================
+    //
+    // may throw type_error or out_of_range
+    //
+    value_type&       at(const key& k)
+    {
+        return this->as_table().at(k);
+    }
+    value_type const& at(const key& k) const
+    {
+        return this->as_table().at(k);
+    }
+    value_type&       operator[](const key& k)
+    {
+        if(this->is_uninitialized())
+        {
+            *this = table_type{};
+        }
+        return this->as_table()[k];
+    }
+
+    value_type&       at(const std::size_t idx)
+    {
+        return this->as_array().at(idx);
+    }
+    value_type const& at(const std::size_t idx) const
+    {
+        return this->as_array().at(idx);
+    }
+
+    value_type&       operator[](const std::size_t idx) noexcept
+    {
+        return this->as_array(std::nothrow)[idx];
+    }
+    value_type const& operator[](const std::size_t idx) const noexcept
+    {
+        return this->as_array(std::nothrow)[idx];
+    }
+
+    void push_back(const value_type& x)
+    {
+        if(this->type_ != value_t::array)
+        {
+            throw type_error(detail::format_underline(
+                "toml::value::push_back(value): bad_cast to array type", {
+                    {this->region_info_.get(),
+                     concat_to_string("the actual type is ", this->type_)}
+                }), this->location());
+        }
+        this->as_array(std::nothrow).push_back(x);
+        return;
+    }
+    void push_back(value_type&& x)
+    {
+        if(this->type_ != value_t::array)
+        {
+            throw type_error(detail::format_underline(
+                "toml::value::push_back(value): bad_cast to array type", {
+                    {this->region_info_.get(),
+                     concat_to_string("the actual type is ", this->type_)}
+                }), this->location());
+        }
+        this->as_array(std::nothrow).push_back(std::move(x));
+        return;
+    }
+
+    template<typename ... Ts>
+    value_type& emplace_back(Ts&& ... args)
+    {
+        if(this->type_ != value_t::array)
+        {
+            throw type_error(detail::format_underline(
+                "toml::value::emplace_back(value): bad_cast to array type", {
+                    {this->region_info_.get(),
+                     concat_to_string("the actual type is ", this->type_)}
+                }), this->location());
+        }
+        this->as_array(std::nothrow).emplace_back(std::forward<Ts>(args) ...);
+        return this->as_array(std::nothrow).back();
+    }
+
+    std::size_t size() const
+    {
+        switch(this->type_)
+        {
+            case value_t::array:
+            {
+                return this->as_array().size();
+            }
+            case value_t::table:
+            {
+                return this->as_table().size();
+            }
+            case value_t::string:
+            {
+                return this->as_string().str.size();
+            }
+            default:
+            {
+                throw type_error(detail::format_underline(
+                    "toml::value::size(): bad_cast to container types", {
+                        {this->region_info_.get(),
+                         concat_to_string("the actual type is ", this->type_)}
+                    }), this->location());
+            }
+        }
+    }
+
+    std::size_t count(const key_type& k) const
+    {
+        if(this->type_ != value_t::table)
+        {
+            throw type_error(detail::format_underline(
+                "toml::value::count(key): bad_cast to table type", {
+                    {this->region_info_.get(),
+                     concat_to_string("the actual type is ", this->type_)}
+                }), this->location());
+        }
+        return this->as_table().count(k);
+    }
+
+    bool contains(const key_type& k) const
+    {
+        if(this->type_ != value_t::table)
+        {
+            throw type_error(detail::format_underline(
+                "toml::value::contains(key): bad_cast to table type", {
+                    {this->region_info_.get(),
+                     concat_to_string("the actual type is ", this->type_)}
+                }), this->location());
+        }
+        return (this->as_table().count(k) != 0);
+    }
+
     source_location location() const
     {
         return source_location(this->region_info_.get());
@@ -1821,25 +1956,27 @@ operator>=(const basic_value<C, T, A>& lhs, const basic_value<C, T, A>& rhs)
 template<typename C, template<typename ...> class T, template<typename ...> class A>
 inline std::string format_error(const std::string& err_msg,
         const basic_value<C, T, A>& v, const std::string& comment,
-        std::vector<std::string> hints = {})
+        std::vector<std::string> hints = {},
+        const bool colorize = TOML11_ERROR_MESSAGE_COLORIZED)
 {
     return detail::format_underline(err_msg,
         std::vector<std::pair<detail::region_base const*, std::string>>{
             {std::addressof(detail::get_region(v)), comment}
-        }, std::move(hints));
+        }, std::move(hints), colorize);
 }
 
 template<typename C, template<typename ...> class T, template<typename ...> class A>
 inline std::string format_error(const std::string& err_msg,
         const toml::basic_value<C, T, A>& v1, const std::string& comment1,
         const toml::basic_value<C, T, A>& v2, const std::string& comment2,
-        std::vector<std::string> hints = {})
+        std::vector<std::string> hints = {},
+        const bool colorize = TOML11_ERROR_MESSAGE_COLORIZED)
 {
     return detail::format_underline(err_msg,
         std::vector<std::pair<detail::region_base const*, std::string>>{
             {std::addressof(detail::get_region(v1)), comment1},
             {std::addressof(detail::get_region(v2)), comment2}
-        }, std::move(hints));
+        }, std::move(hints), colorize);
 }
 
 template<typename C, template<typename ...> class T, template<typename ...> class A>
@@ -1847,14 +1984,15 @@ inline std::string format_error(const std::string& err_msg,
         const toml::basic_value<C, T, A>& v1, const std::string& comment1,
         const toml::basic_value<C, T, A>& v2, const std::string& comment2,
         const toml::basic_value<C, T, A>& v3, const std::string& comment3,
-        std::vector<std::string> hints = {})
+        std::vector<std::string> hints = {},
+        const bool colorize = TOML11_ERROR_MESSAGE_COLORIZED)
 {
     return detail::format_underline(err_msg,
         std::vector<std::pair<detail::region_base const*, std::string>>{
             {std::addressof(detail::get_region(v1)), comment1},
             {std::addressof(detail::get_region(v2)), comment2},
             {std::addressof(detail::get_region(v3)), comment3}
-        }, std::move(hints));
+        }, std::move(hints), colorize);
 }
 
 template<typename Visitor, typename C,