GitHub - boostorg/spirit_x4: A modern, header-only PEG parser combinator library for C++23 (original) (raw)

Spirit.X4

Spirit.X4 is currently under heavy development.

This library is official, but still under progress, and is not part of the boostorg/boost superproject (yet).

For background information, see:

• https://lists.boost.org/archives/list/boost@lists.boost.org/thread/K3EQLEQJHEUBROB6ODUKTZHFP2FDUS2E/?sort=date
• boostorg/spirit#795
• boostorg/spirit#807

Boost.Spirit.X4 is a modern, header-only PEG parser combinator library for C++23. It lets you write EBNF-like grammars directly in C++ with deterministic, top-down parsing (ordered choice, lookahead, greedy repetition).

X4 succeeds Boost.Spirit.X3 and is redesigned for clarity, maintainability, and performance using modern C++ features such as concepts and constexpr.

X4 scales from quick prototypes to production parsers for DSLs, data formats, and interpreters.

Supported Environments

• C++23 and C++26
• GCC 14
• Clang 21
• MSVC 2022

How to use Spirit

Step 1. Setup the Boost superproject

For applications:

cd my_app

git submodule add https://github.com/boostorg/boost.git modules/boost cd modules/boost

Not required after X4 is officially shipped

git submodule add https://github.com/boostorg/spirit_x4.git libs/spirit_x4

For Spirit development:

git clone https://github.com/boostorg/boost.git cd boost

Not required after X4 is officially shipped

git clone https://github.com/boostorg/spirit_x4.git libs/spirit_x4

Step 2. Setup the dependent Boost libraries

We're trying hard to reduce these dependencies. We aim to remove these entirely in the future.

git submodule update --init --depth 1 --recursive --
tools/build tools/boost_install libs/assert libs/bind libs/config
libs/container_hash libs/core libs/describe libs/detail
libs/function libs/function_types libs/functional libs/fusion
libs/integer libs/io libs/mp11 libs/mpl libs/predef libs/preprocessor
libs/static_assert libs/throw_exception libs/tuple libs/type_index
libs/type_traits libs/typeof libs/utility libs/variant

Linux

./bootstrap.sh ./b2 headers

Windows

.\bootstrap.bat .\b2 headers

Step 3. Start using Spirit

For applications:

Edit your CMakeLists.txt:

add_subdirectory(modules/boost/libs/spirit_x4) target_link_libraries(my_app PRIVATE Boost::spirit_x4)

For developing Spirit:

cd libs/spirit_x4 cmake -B build

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