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<p align="center"> <strong>✨&#xFE0F; This README is fine, but the <a href="https://marzer.github.io/tomlplusplus/">toml++ homepage</a> is better. ✨&#xFE0F;</strong> </p> <br>

Library features

<br>

Basic usage

ℹ️ The following example favours brevity. If you'd prefer full API documentation and lots of specific code snippets instead, visit the project homepage

Given a TOML file configuration.toml containing the following:

[library]
name = "toml++"
authors = ["Mark Gillard <mark.gillard@outlook.com.au>"]

[dependencies]
cpp = 17

Reading it in C++ is easy with toml++:

#include <toml++/toml.hpp>

using namespace std::literals;

auto config = toml::parse_file( "configuration.toml" );

// get key-value pairs
std::string_view library_name = config["library"]["name"].value_or(""sv);
std::string_view library_author = config["library"]["authors"][0].value_or(""sv);
int64_t depends_on_cpp_version = config["dependencies"]["cpp"].value_or(0);

// modify the data
config.insert_or_assign("alternatives", toml::array{
    "cpptoml",
    "toml11",
    "Boost.TOML"
});

// use a visitor to iterate over heterogenous data
config.for_each([](auto& key, auto& value)
{
    std::cout << value << "\n";
    if constexpr (toml::is_string<decltype(value)>)
        do_something_with_string_values(value);
});

// you can also iterate more 'traditionally' using a ranged-for
for (auto&& [k, v] : config)
{
    // ...
}

// re-serialize as TOML
std::cout << config << "\n";

// re-serialize as JSON
std::cout << toml::json_formatter{ config } << "\n";

// re-serialize as YAML
std::cout << toml::yaml_formatter{ config } << "\n";

You'll find some more code examples in the examples directory, and plenty more as part of the API documentation.

<br>

Adding toml++ to your project

toml++ comes in two flavours: Single-header and Regular. The API is the same for both.

🍦️ Single-header flavour

  1. Drop toml.hpp wherever you like in your source tree
  2. There is no step two

🍨️ Regular flavour

  1. Clone the repository
  2. Add tomlplusplus/include to your include paths
  3. #include <toml++/toml.hpp>

Conan

Add tomlplusplus/3.4.0 to your conanfile.

DDS

Add tomlpp to your package.json5, e.g.:

depends: [
    'tomlpp^3.4.0',
]

ℹ️ What is DDS?

Tipi.build

tomlplusplus can be easily used in tipi.build projects by adding the following entry to your .tipi/deps:

{
	"marzer/tomlplusplus": {}
}

Vcpkg

vcpkg install tomlplusplus

Meson

You can install the wrap with:

meson wrap install tomlplusplus

After that, you can use it like a regular dependency:

tomlplusplus_dep = dependency('tomlplusplus')

You can also add it as a subproject directly.

CMake FetchContent

include(FetchContent)
FetchContent_Declare(
    tomlplusplus
    GIT_REPOSITORY https://github.com/marzer/tomlplusplus.git
    GIT_TAG        v3.4.0
)
FetchContent_MakeAvailable(tomlplusplus)
# Example add library: target_link_libraries(MyApp tomlplusplus::tomlplusplus)

ℹ️ What is FetchContent?

Git submodules

git submodule add --depth 1 https://github.com/marzer/tomlplusplus.git tomlplusplus

Other environments and package managers

The C++ tooling ecosystem is a fractal nightmare of unbridled chaos so naturally I'm not up-to-speed with all of the available packaging and integration options. I'm always happy to see new ones supported, though! If there's some integration you'd like to see and have the technical know-how to make it happen, feel free to make a pull request.

What about dependencies?

If you just want to consume toml++ as a regular library then you don't have any dependencies to worry about. There's a few test-related dependencies to be aware of if you're working on the library, though. See CONTRIBUTING for information.

<br>

Configuration

A number of configurable options are exposed in the form of preprocessor #defines Most likely you won't need to mess with these at all, but if you do, set them before including toml++.

OptionTypeDescriptionDefault
TOML_ASSERT(expr)function macroSets the assert function used by the library.assert()
TOML_CALLCONVdefineCalling convention to apply to exported free/static functions.undefined
TOML_CONFIG_HEADERstring literalIncludes the given header file before the rest of the library.undefined
TOML_ENABLE_FORMATTERSbooleanEnables the formatters. Set to 0 if you don't need them to improve compile times and binary size.1
TOML_ENABLE_FLOAT16booleanEnables support for the built-in _Float16 type.per compiler settings
TOML_ENABLE_PARSERbooleanEnables the parser. Set to 0 if you don't need it to improve compile times and binary size.1
TOML_ENABLE_UNRELEASED_FEATURESbooleanEnables support for unreleased TOML language features.0
TOML_ENABLE_WINDOWS_COMPATbooleanEnables support for transparent conversion between wide and narrow strings.1 on Windows
TOML_EXCEPTIONSbooleanSets whether the library uses exceptions.per compiler settings
TOML_EXPORTED_CLASSdefineAPI export annotation to add to classes.undefined
TOML_EXPORTED_MEMBER_FUNCTIONdefineAPI export annotation to add to non-static class member functions.undefined
TOML_EXPORTED_FREE_FUNCTIONdefineAPI export annotation to add to free functions.undefined
TOML_EXPORTED_STATIC_FUNCTIONdefineAPI export annotation to add to static functions.undefined
TOML_HEADER_ONLYbooleanDisable this to explicitly control where toml++'s implementation is compiled (e.g. as part of a library).1
TOML_IMPLEMENTATIONdefineDefine this to enable compilation of the library's implementation when TOML_HEADER_ONLY == 0.undefined
TOML_OPTIONAL_TYPEtype nameOverrides the optional<T> type used by the library if you need something better than std::optional.undefined
TOML_SMALL_FLOAT_TYPEtype nameIf your codebase has a custom 'small float' type (e.g. half-precision), this tells toml++ about it.undefined
TOML_SMALL_INT_TYPEtype nameIf your codebase has a custom 'small integer' type (e.g. 24-bits), this tells toml++ about it.undefined

ℹ️ A number of these have ABI implications; the library uses inline namespaces to prevent you from accidentally linking incompatible combinations together.

<br>

TOML Language Support

At any given time the library aims to support whatever the most recently-released version of TOML is, with opt-in support for a number of unreleased features from the TOML master and some sane cherry-picks from the TOML issues list where the discussion strongly indicates inclusion in a near-future release.

The library advertises the most recent numbered language version it fully supports via the preprocessor defines TOML_LANG_MAJOR, TOML_LANG_MINOR and TOML_LANG_PATCH.

Unreleased language features:

ℹ️ #define TOML_ENABLE_UNRELEASED_FEATURES 1 to enable these features (see Configuration).

🔹️ TOML v1.0.0:

All features supported, including:

🔹️ TOML v0.5.0:

All features supported.

<br>

Contributing

Contributions are very welcome! Either by reporting issues or submitting pull requests. If you wish to submit a pull request, please see CONTRIBUTING for all the details you need to get going.

<br>

License and Attribution

toml++ is licensed under the terms of the MIT license - see LICENSE.

UTF-8 decoding is performed using a state machine based on Bjoern Hoehrmann's 'Flexible and Economical UTF-8 Decoder'.

With thanks to:

Contact

For bug reports and feature requests please consider using the issues system here on GitHub. For anything else though you're welcome to reach out via other means. In order of likely response time: