"enum to string in modern c++11 / c++14 / c++17 and future c++20" Answer’s

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Magic Enum header-only library provides static reflection for enums (to string, from string, iteration) for C++17.

#include <magic_enum.hpp>

enum Color { RED = 2, BLUE = 4, GREEN = 8 };

Color color = Color::RED;
auto color_name = magic_enum::enum_name(color);
// color_name -> "RED"

std::string color_name{"GREEN"};
auto color = magic_enum::enum_cast<Color>(color_name)
if (color.has_value()) {
  // color.value() -> Color::GREEN
};

For more examples check home repository https://github.com/Neargye/magic_enum.

Where is the drawback?

This library uses a compiler-specific hack (based on __PRETTY_FUNCTION__ / __FUNCSIG__), which works on Clang >= 5, MSVC >= 15.3 and GCC >= 9.

Enum value must be in range [MAGIC_ENUM_RANGE_MIN, MAGIC_ENUM_RANGE_MAX].

  • By default MAGIC_ENUM_RANGE_MIN = -128, MAGIC_ENUM_RANGE_MAX = 128.

  • If need another range for all enum types by default, redefine the macro MAGIC_ENUM_RANGE_MIN and MAGIC_ENUM_RANGE_MAX.

  • MAGIC_ENUM_RANGE_MIN must be less or equals than 0 and must be greater than INT16_MIN.

  • MAGIC_ENUM_RANGE_MAX must be greater than 0 and must be less than INT16_MAX.

  • If need another range for specific enum type, add specialization enum_range for necessary enum type.

    #include <magic_enum.hpp>
    
    enum number { one = 100, two = 200, three = 300 };
    
    namespace magic_enum {
    template <>
      struct enum_range<number> {
        static constexpr int min = 100;
        static constexpr int max = 300;
    };
    }
    
Tuesday, June 1, 2021
 
Sidarta
answered 8 Months ago
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