[][homepage]
[](https://github.com/marzer/tomlplusplus/releases)
[][cpp_compilers]
[][cpp_compilers]
[][v1.0.0]
[](./LICENSE)
[](https://github.com/marzer/tomlplusplus/actions/workflows/ci.yaml)
[](https://github.com/fffaraz/awesome-cpp)
====
# toml++ homepage
✨️ This README is fine, but the toml++ homepage is better. ✨️
# Library features
- Header-only
- Supports the latest [TOML] release ([v1.0.0]), plus optional support for some [unreleased TOML language features]
- C++17 (plus some C++20 features where available, e.g. experimental support for char8_t strings)
- Proper UTF-8 handling (incl. BOM)
- Works with or without exceptions
- Doesn't require RTTI
- Support for serializing to JSON and YAML
- Tested on Clang (6+), GCC (7+) and MSVC (VS2019, VS2022)
- Tested on x64, x86 and ARM
# 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:
```toml
[library]
name = "toml++"
authors = ["Mark Gillard "]
[dependencies]
cpp = 17
```
Reading it in C++ is easy with toml++:
```cpp
#include
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"
});
// iterate & visit over the data
for (auto&& [k, v] : config)
{
v.visit([](auto& node) noexcept
{
std::cout << node << "\n";
if constexpr (toml::is_string)
do_something_with_string_values(node);
});
}
// 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].
# 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. Add `tomlplusplus/include` to your include paths
2. `#include `
### Conan
Add `tomlplusplus/3.0.1` to your conanfile.
### DDS
Add `tomlpp` to your `package.json5`, e.g.:
```
depends: [
'tomlpp^3.0.1',
]
```
> ℹ️ _[What is DDS?](https://dds.pizza/)_
### Vcpkg
```
vcpkg install tomlplusplus
```
### CMake FetchContent
```
include(FetchContent)
FetchContent_Declare(
tomlplusplus
GIT_REPOSITORY https://github.com/marzer/tomlplusplus.git
GIT_TAG v3.0.1
)
FetchContent_MakeAvailable(tomlplusplus)
```
> ℹ️ _[What is FetchContent?](https://cmake.org/cmake/help/latest/module/FetchContent.html)_
### Other environments and package managers
`toml++` is a fairly new project and I'm not up-to-speed with all of the available packaging and integration options
in the C++ ecosystem. I'm also a cmake novice, for better or worse. If there's an integration option missing be
assured that I fully support it being added, and welcome [pull requests](./CONTRIBUTING.md)!
### 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.
# 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++.
| Option | Type | Description | Default |
|-----------------------------------|:--------------:|----------------------------------------------------------------------------------------------------------|------------------------|
| `TOML_ASSERT(expr)` | function macro | Sets the assert function used by the library. | `assert()` |
| `TOML_CONFIG_HEADER` | string literal | Includes the given header file before the rest of the library. | undefined |
| `TOML_ENABLE_FORMATTERS` | boolean | Enables the formatters. Set to `0` if you don't need them to improve compile times and binary size. | `1` |
| `TOML_ENABLE_PARSER` | boolean | Enables the parser. Set to `0` if you don't need it to improve compile times and binary size. | `1` |
| `TOML_ENABLE_UNRELEASED_FEATURES` | boolean | Enables support for [unreleased TOML language features]. | `0` |
| `TOML_ENABLE_WINDOWS_COMPAT` | boolean | Enables support for transparent conversion between wide and narrow strings. | `1` on Windows |
| `TOML_EXCEPTIONS` | boolean | Sets whether the library uses exceptions. | per compiler settings |
| `TOML_EXPORTED_CLASS` | define | API export annotation to add to classes. | undefined |
| `TOML_EXPORTED_MEMBER_FUNCTION` | define | API export annotation to add to non-static class member functions. | undefined |
| `TOML_EXPORTED_FREE_FUNCTION` | define | API export annotation to add to free functions. | undefined |
| `TOML_EXPORTED_STATIC_FUNCTION` | define | API export annotation to add to static functions. | undefined |
| `TOML_HEADER_ONLY` | boolean | Disable this to explicitly control where toml++'s implementation is compiled (e.g. as part of a library).| `1` |
| `TOML_IMPLEMENTATION` | define | Define this to enable compilation of the library's implementation when `TOML_HEADER_ONLY` == `0`. | undefined |
| `TOML_OPTIONAL_TYPE` | type name | Overrides the `optional` type used by the library if you need [something better than std::optional]. | undefined |
| `TOML_SMALL_FLOAT_TYPE` | type name | If your codebase has a custom 'small float' type (e.g. half-precision), this tells toml++ about it. | undefined |
| `TOML_SMALL_INT_TYPE` | type name | If 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._
# 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:**
- [#516]: Allow newlines and trailing commas in inline tables
- [#562]: Allow hex floating-point values
- [#644]: Support `+` in key names
- [#671]: Local time of day format should support `09:30` as opposed to `09:30:00`
- [#687]: Relax bare key restrictions to allow additional unicode characters
- [#796]: Include an \xHH escape code sequence
> ℹ️ _`#define TOML_ENABLE_UNRELEASED_FEATURES 1` to enable these features (see [Configuration](#Configuration))._
### 🔹️ **TOML v1.0.0:**
All features supported, including:
- [#356]: Allow leading zeros in the exponent part of a float
- [#567]: Control characters are not permitted in comments
- [#571]: Allow raw tabs inside strings
- [#665]: Make arrays heterogeneous
- [#766]: Allow comments before commas in arrays
### 🔹️ **TOML v0.5.0:**
All features supported.
# 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.
# 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:
- **[@beastle9end](https://github.com/beastle9end)** - Made Windows.h include bypass
- **[@bjadamson](https://github.com/bjadamson)** - Reported some bugs and helped design a new feature
- **[@bobfang1992](https://github.com/bobfang1992)** - Reported a bug and created a [wrapper in python](https://github.com/bobfang1992/pytomlpp)
- **[@GiulioRomualdi](https://github.com/GiulioRomualdi)** - Added cmake+meson support
- **[@levicki](https://github.com/levicki)** - Helped design some new features
- **[@moorereason](https://github.com/moorereason)** - Reported a whole bunch of bugs
- **[@mosra](https://github.com/mosra)** - Created the awesome [m.css] used to generate the API docs
- **[@ned14](https://github.com/ned14)** - Reported a bunch of bugs and helped design some new features
- **[@okureta](https://github.com/okureta)** - Reported a bug
- **[@prince-chrismc](https://github.com/prince-chrismc)** - Added toml++ to ConanCenter, and fixed some typos
- **[@rbrugo](https://github.com/rbrugo)** - Helped design a new feature
- **[@Reedbeta](https://github.com/Reedbeta)** - Fixed a bug and added additional Visual Studio debugger native visualizers
- **[@Ryan-rsm-McKenzie](https://github.com/Ryan-rsm-McKenzie)** - Add natvis file to cmake install script
- **[@shdnx](https://github.com/shdnx)** - Fixed a bug on GCC 8.2.0 and some meson config issues
- **[@sneves](https://github.com/sneves)** - Helped fix a number of parser bugs
- **[@sobczyk](https://github.com/sobczyk)** - Reported some bugs
- **[@std-any-emplace](https://github.com/std-any-emplace)** - Reported some bugs
- **[@Tachi107](https://github.com/Tachi107)** - Made some tweaks to meson.build, added compile_library build option
- **[@traversaro](https://github.com/traversaro)** - Added vcpkg support and reported a bunch of bugs
- **[@whiterabbit963](https://github.com/whiterabbit963)** - Fixed a bug with value_or conversions
- **[@ximion](https://github.com/ximion)** - Added support for installation with meson
# 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:
- Twitter: [marzer8789](https://twitter.com/marzer8789)
- Email: [mark.gillard@outlook.com.au](mailto:mark.gillard@outlook.com.au)
- Facebook: [marzer](https://www.facebook.com/marzer)
- LinkedIn: [marzer](https://www.linkedin.com/in/marzer/)
[API documentation]: https://marzer.github.io/tomlplusplus/
[homepage]: https://marzer.github.io/tomlplusplus/
[unreleased TOML language features]: #unreleased-language-features
[most recently-released version]: https://github.com/toml-lang/toml/releases
[numbered version]: https://github.com/toml-lang/toml/releases
[char8_t]: https://en.cppreference.com/w/cpp/keyword/char8_t
[TOML]: https://toml.io/
[TOML master]: https://github.com/toml-lang/toml/blob/master/README.md
[TOML issues list]: https://github.com/toml-lang/toml/issues
[v1.0.0]: https://toml.io/en/v1.0.0
[CONTRIBUTING]: ./CONTRIBUTING.md
[LICENSE]: ./LICENSE
[Flexible and Economical UTF-8 Decoder]: http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
[cpp_compilers]: https://en.cppreference.com/w/cpp/compiler_support
[reporting issues]: https://github.com/marzer/tomlplusplus/issues/new/choose
[feature request]: https://github.com/marzer/tomlplusplus/issues/new/choose
[issues]: https://github.com/marzer/tomlplusplus/issues
[#356]: https://github.com/toml-lang/toml/issues/356
[#516]: https://github.com/toml-lang/toml/issues/516
[#562]: https://github.com/toml-lang/toml/issues/562
[#567]: https://github.com/toml-lang/toml/issues/567
[#571]: https://github.com/toml-lang/toml/issues/571
[#622]: https://github.com/toml-lang/toml/issues/622
[#644]: https://github.com/toml-lang/toml/issues/644
[#665]: https://github.com/toml-lang/toml/issues/665
[#671]: https://github.com/toml-lang/toml/issues/671
[#687]: https://github.com/toml-lang/toml/issues/687
[#796]: https://github.com/toml-lang/toml/pull/796
[#766]: https://github.com/toml-lang/toml/issues/766
[something better than std::optional]: https://github.com/TartanLlama/optional
[m.css]: https://mcss.mosra.cz/documentation/doxygen