compile time regex

compiletimereGex.cpp

/*
cmake_minimum_required(VERSION 3.30)

project(reGex LANGUAGES C CXX)

set(CMAKE_CXX_STANDARD 23)

add_subdirectory(ctre)

set(SOURCES
    main.cpp
)
add_executable(${PROJECT_NAME} ${SOURCES})
target_link_libraries(${PROJECT_NAME}
    PRIVATE
        ctre # https://github.com/hanickadot/compile-time-regular-expressions.git
)
target_compile_options(${PROJECT_NAME} PUBLIC "$<$<C_COMPILER_ID:MSVC>:/utf-8>")
target_compile_options(${PROJECT_NAME} PUBLIC "$<$<C_COMPILER_ID:GNU>:-fconstexpr-ops-limit=1000000>")
*/
#include <ctre.hpp>
#include <iostream>
#include <array>
#include <locale>
#include <codecvt>

struct Enum 
{
    std::basic_string_view<char32_t> code{}, name{}, vs{};
    friend std::ostream& operator << (std::ostream& o, const Enum& a){
        std::wstring_convert<std::codecvt_utf8<char32_t>, char32_t> converter;
        std::string codeu = converter.to_bytes(a.code.data(), a.code.data() + a.code.size());
        std::string nameu = converter.to_bytes(a.name.data(), a.name.data() + a.name.size());
        std::string vsu = converter.to_bytes(a.vs.data(), a.vs.data() + a.vs.size());
        return o 
            << "code: " << codeu << "\n"
            << "name: " << nameu << "\n"
            << "vs: "   << vsu << "\n";
    }
};

template <ctll::fixed_string Input>
consteval auto parse_enums() {
    constexpr auto pattern = ctll::fixed_string{R"(\benum\s+(?:class\s+)?(\w+)\s*(?::\s*\w+)?\s*\{\s*([^}]+?)\s*\}\s*;)"};
    constexpr auto matches = ctre::search_all<pattern>(Input);
    
    constexpr size_t count = [&]() constexpr {
        size_t n = 0;
        for (auto match : matches) ++n;
        return n;
    }();
    
    std::array<Enum, count> arr{};
    size_t i = 0;
    for (auto match : matches) {
        arr[i++] = Enum{
            .code = match.template get<0>().to_view(),
            .name = match.template get<1>().to_view(), 
            .vs   = match.template get<2>().to_view()
        };
    }
    return arr;
}

constexpr auto input = ctll::fixed_string(R"(
    enum Color { Red, Green, Blue };
    enum class Fruit : int { Apple, Banana };
    enum class TrafficLight : int { Red, Yellow = 1, Green };
    enum class Status { Ok, Error = 0x12ff00 };
    enum class GATE : bool { OPEN = true, CLOSE = false };
)");

constinit auto r = parse_enums<input>();

int main() {
    for (const auto& e : r) {
        std::cout << e << "\n";
    }
}