enum_name

Converting (scoped)enum values to/from string names written in C++>=11.

Supported Compilers

• Clang > 5
• GCC > 8
• MSVC > 2015

Features

• Supports enum and enum class
• Supports enums in namespaces, classes or structs even templated or not
• Supports compile-time as much as possible using with C++17 and later
• Changing enum range with template parameter _{(default range: [0, 256))} on each call or with your special function for types or adding specialized enum_range<Enum> struct
• Supports and automatically overloaded operator<< for Enum types to direct using with ostream objects
• Supports custom enum name output by explicit specialization of constexpr inline auto mgutility::detail::enum_type::name<Enum, EnumValue>() noexcept function
• Supports bitmasked enums and auto detect them
• Supports iterate over enum (names and values) with mgutility::enum_for_each<T>() class and it is compatible with standard ranges and views

Limitations

• Compiler versions
• Wider range can increase compile time so user responsible to adjusting for enum's range

Usage (try it!)

#include <iostream>
#include "enum_name.hpp"

enum class rgb_color {
    red = 1 << 0,
    green = 1 << 1,
    blue = 1 << 2,
    unknown = -1
};

auto operator|(rgb_color lhs, rgb_color rhs) -> rgb_color {
    return static_cast<rgb_color>(mgutility::enum_to_underlying(lhs) |
                                  mgutility::enum_to_underlying(rhs));
}

auto operator&(rgb_color lhs, rgb_color rhs) -> rgb_color {
    return static_cast<rgb_color>(mgutility::enum_to_underlying(lhs) &
                                  mgutility::enum_to_underlying(rhs));
}

// specialize rgb_color::unknown to make output "UNKNOWN" instead of "unknown"
template <>
constexpr inline auto
mgutility::detail::enum_type::name<rgb_color, rgb_color::unknown>() noexcept
    -> string_view {
    return "UNKNOWN";
}

// you can specialize enum ranges with overload per enum types (option 1)
template <>
struct mgutility::enum_range<rgb_color> {
    static constexpr auto min = -1;
    static constexpr auto max = 5;
};

// you can specialize enum ranges with overload per enum types (option 2)
auto enum_name = [](rgb_color c) { return mgutility::enum_name<-1, 5>(c); };

#if defined(__cpp_lib_print)
#include <print>
#include <ranges>
#endif

int main() {
    auto x = rgb_color::blue;
    auto y = mgutility::to_enum<rgb_color>("green|red");

#if defined(__cpp_lib_print)

    // enum_for_each<T> can usable with views and range algorithms
    auto colors = mgutility::enum_for_each<rgb_color>() |
                  std::ranges::views::filter([](auto &&pair) {
                      return !pair.second.empty() && pair.second != "UNKNOWN";
                  });

    std::ranges::for_each(colors, [](auto &&color) {
        std::println("{} \t: {}", color.second,
                     mgutility::enum_to_underlying(color.first));
    });

#else

    for (auto&& e : mgutility::enum_for_each<rgb_color>()) {
        if (!e.second.empty() && e.second != "UNKNOWN") {
            std::cout << e.second
                      << " \t: " << mgutility::enum_to_underlying(e.first)
                      << '\n';
        }
        // std::pair<Enum, string_view> {enum_type, name_of_enum}
    }
#endif

    // default signature: enum_name<min_value = -128, max_value = 128, Enum
    // typename>(Enum&&) Changing max_value to not too much greater than enum's
    // max value, it will compiles faster
    std::cout << x << '\n';  // will print "blue" to output

    // calling specialized enum ranges function for rgb_color type
    // will print "green" to output, if y can't convert to rgb_color prints
    // "UNKNOWN"
    std::cout << enum_name(y.value_or(rgb_color::unknown)) << '\n';
}