cprep

cprep is a macro and include preprocessor for C-like language written in C++20.

Some features those are not so well supported by certain toolchains (like NDK, emsdk) are not used, like <format>. But requires is used.

Basic Usage

#include <cprep/cprep.hpp>

class Includer final : public pep::cprep::ShaderIncluder {
public:
    bool require_header(std::string_view header_name, std::string_view file_path, Result &result) override {
        // handle `include`
        // ...
    }

    void clear() override {
        // clear read files
    }
};

pep::cprep::Preprocessor preprocessor{};
TestIncluder includer{};
auto in_src_path = "foo.cpp";
auto in_src_count = read_all_from_file(in_src_path);
auto result = preprocessor.do_preprocess(in_src_path, in_src_content, includer);

std::cout << result.parsed_result << std::endl;
std::cout << result.error << std::endl;
std::cout << result.warning << std::endl;

Features

Supported directives

• define, undef
• if, else, elif, endif, ifdef, ifndef
• elifdef, elifndef
• error, warning
• include
• pragma once
• line

Supported features

• basic object-like and function-like macro, stringification # and concatenation ##
• -D and -U options (both -Dxxx=xxx and -D xxx=xxx are ok)
• defined(), __has_include()
• __FILE__, __LINE__
• variable number of parameters, __VA_ARGS__, __VA_OPT__
• allow single ' between numbers in integer or floating-point literal
• customized include handler
• unknown directives, pragmas and includes are reserved, and a corresponding warning is added
• UTF-8 input and unicode identifier (but only UTF-8 input is acceptable currently)

Integration

One can just add the source files to the project or use add_subdirectory(pep-cprep) add link to target pep-cprep when using CMake.

One can set CPREP_BUILD_OBJECT_LIB to ON to make pep-cprep an object target, which can be integrated into some static library.

One can define PEP_CPREP_INLINE_NAMESPACE in cprep/config.hpp, or set variable CPREP_INLINE_NAMESPACE before add_subdirectory() in CMake, or add target_compile_definitions() to target pep-cperp to define an inline namespace name. By default, the namespace is pep::cprep::inline <version>, if PEP_CPREP_INLINE_NAMESPACE is set to foo for example, the namespace becomes pep::cprep::inline foo. This is useful when cprep is expected to be bundled inside a static library to avoid symbol conflicting.

Acknowledgement

The source unicode_ident.cpp is modified from Unicode ident by dtolnay.