Magic Enum C++

Header-only C++17 library provides static reflection for enums, work with any enum type without any macro or boilerplate code.

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Documentation

• Reference
• Limitations
• Integration

Features & Examples

• Basic

```cpp #include #include

enum class Color { RED = -10, BLUE = 0, GREEN = 10 };

int main() { Color c1 = Color::RED; std::cout << magic_enum::enum_name(c1) << std::endl; // RED return 0; } ```

• Enum value to string

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

• String to enum value

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

// case insensitive enum_cast auto color = magic_enum::enum_cast(value, magic_enum::case_insensitive);

// enum_cast with BinaryPredicate auto color = magic_enum::enum_cast(value, { return std::tolower(lhs) == std::tolower(rhs); });

// enum_cast with default auto color_or_default = magic_enum::enum_cast(value).value_or(Color::NONE); ```

• Integer to enum value

```cpp int color_integer = 0; auto color = magic_enum::enum_cast(color_integer); if (color.has_value()) { // color.value() -> Color::BLUE }

auto color_or_default = magic_enum::enum_cast(value).value_or(Color::NONE); ```

• Indexed access to enum value

cpp std::size_t i = 0; Color color = magic_enum::enum_value<Color>(i); // color -> Color::RED

• Enum value sequence

cpp constexpr auto colors = magic_enum::enum_values<Color>(); // colors -> {Color::RED, Color::BLUE, Color::GREEN} // colors[0] -> Color::RED

• Number of enum elements

cpp constexpr std::size_t color_count = magic_enum::enum_count<Color>(); // color_count -> 3

• Enum value to integer

cpp Color color = Color::RED; auto color_integer = magic_enum::enum_integer(color); // or magic_enum::enum_underlying(color); // color_integer -> -10

• Enum names sequence

cpp constexpr auto color_names = magic_enum::enum_names<Color>(); // color_names -> {"RED", "BLUE", "GREEN"} // color_names[0] -> "RED"

• Enum entries sequence

cpp constexpr auto color_entries = magic_enum::enum_entries<Color>(); // color_entries -> {{Color::RED, "RED"}, {Color::BLUE, "BLUE"}, {Color::GREEN, "GREEN"}} // color_entries[0].first -> Color::RED // color_entries[0].second -> "RED"

• Enum fusion for multi-level switch/case statements

cpp switch (magic_enum::enum_fuse(color, direction).value()) { case magic_enum::enum_fuse(Color::RED, Directions::Up).value(): // ... case magic_enum::enum_fuse(Color::BLUE, Directions::Down).value(): // ... // ... }

• Enum switch runtime value as constexpr constant cpp Color color = Color::RED; magic_enum::enum_switch([] (auto val) { constexpr Color c_color = val; // ... }, color);

• Enum iterate for each enum as constexpr constant cpp magic_enum::enum_for_each<Color>([] (auto val) { constexpr Color c_color = val; // ... });

• Check if enum contains

cpp magic_enum::enum_contains(Color::GREEN); // -> true magic_enum::enum_contains<Color>(2); // -> true magic_enum::enum_contains<Color>(123); // -> false magic_enum::enum_contains<Color>("GREEN"); // -> true magic_enum::enum_contains<Color>("fda"); // -> false

• Enum index in sequence

cpp constexpr auto color_index = magic_enum::enum_index(Color::BLUE); // color_index.value() -> 1 // color_index.has_value() -> true

• Functions for flags

```cpp enum Directions : std::uint64_t { Left = 1, Down = 2, Up = 4, Right = 8, }; template <> struct magic_enum::customize::enum_range { static constexpr bool is_flags = true; };

magic_enum::enum_flags_name(Directions::Up | Directions::Right); // -> "Directions::Up|Directions::Right" magic_enum::enum_flags_name(Directions::Up | Directions::Right, ','); // -> "Directions::Up,Directions::Right" magic_enum::enum_flags_contains(Directions::Up | Directions::Right); // -> true magic_enum::enum_flags_cast(3); // -> "Directions::Left|Directions::Down" magic_enum::enum_flags_cast("Left,Down", ','); // -> Directions::Left|Directions::Down ```

• Enum type name

cpp Color color = Color::RED; auto type_name = magic_enum::enum_type_name<decltype(color)>(); // type_name -> "Color"

• IOstream operator for enum

cpp using magic_enum::iostream_operators::operator<<; // out-of-the-box ostream operators for enums. Color color = Color::BLUE; std::cout << color << std::endl; // "BLUE"

cpp using magic_enum::iostream_operators::operator>>; // out-of-the-box istream operators for enums. Color color; std::cin >> color;

• Bitwise operator for enum

cpp enum class Flags { A = 1 << 0, B = 1 << 1, C = 1 << 2, D = 1 << 3 }; using namespace magic_enum::bitwise_operators; // out-of-the-box bitwise operators for enums. // Support operators: ~, |, &, ^, |=, &=, ^=. Flags flags = Flags::A | Flags::B & ~Flags::C;

• Checks whether type is an Unscoped enumeration.

```cpp enum color { red, green, blue }; enum class direction { left, right };

magic_enum::is_unscoped_enum::value -> true magic_enum::is_unscoped_enum::value -> false magic_enum::is_unscoped_enum

// Helper variable template. magic_enum::is_unscoped_enum_v -> true ```

• Checks whether type is an Scoped enumeration.

```cpp enum color { red, green, blue }; enum class direction { left, right };

magic_enum::is_scoped_enum::value -> false magic_enum::is_scoped_enum::value -> true magic_enum::is_scoped_enum

// Helper variable template. magic_enum::is_scoped_enum_v -> true ```

• Static storage enum variable to string This version is much lighter on the compile times and is not restricted to the enum_range limitation.

cpp constexpr Color color = Color::BLUE; constexpr auto color_name = magic_enum::enum_name<color>(); // color_name -> "BLUE"

• containers::array array container for enums.

cpp magic_enum::containers::array<Color, RGB> color_rgb_array {}; color_rgb_array[Color::RED] = {255, 0, 0}; color_rgb_array[Color::GREEN] = {0, 255, 0}; color_rgb_array[Color::BLUE] = {0, 0, 255}; magic_enum::containers::get<Color::BLUE>(color_rgb_array) // -> RGB{0, 0, 255}

• containers::bitset bitset container for enums.

cpp constexpr magic_enum::containers::bitset<Color> color_bitset_red_green {Color::RED|Color::GREEN}; bool all = color_bitset_red_green.all(); // all -> false // Color::BLUE is missing bool test = color_bitset_red_green.test(Color::RED); // test -> true

• containers::set set container for enums.

cpp auto color_set = magic_enum::containers::set<Color>(); bool empty = color_set.empty(); // empty -> true color_set.insert(Color::GREEN); color_set.insert(Color::BLUE); color_set.insert(Color::RED); std::size_t size = color_set.size(); // size -> 3

• Improved UB-free "SFINAE-friendly" underlying_type.

```cpp magic_enum::underlying_type::type -> int

// Helper types. magic_enum::underlying_type_t -> int ```

Remarks

• magic_enum does not pretend to be a silver bullet for reflection for enums, it was originally designed for small enum.

• Before use, read the limitations of functionality.

Integration

• You should add the required file magic_enum.hpp, and optionally other headers from include dir or release archive. Alternatively, you can build the library with CMake.

• If you are using vcpkg on your project for external dependencies, then you can use the magic-enum package.

• If you are using Conan to manage your dependencies, merely add magic_enum/x.y.z to your conan's requires, where x.y.z is the release version you want to use.

• If you are using Build2 to build and manage your dependencies, add depends: magic_enum ^x.y.z to the manifest file where x.y.z is the release version you want to use. You can then import the target using magic_enum%lib{magic_enum}.

• Alternatively, you can use something like CPM which is based on CMake's Fetch_Content module.

cmake CPMAddPackage( NAME magic_enum GITHUB_REPOSITORY Neargye/magic_enum GIT_TAG vx.y.z # Where `x.y.z` is the release version you want to use. )

• Bazel is also supported, simply add to your WORKSPACE file:

http_archive( name = "magic_enum", strip_prefix = "magic_enum-<commit>", urls = ["https://github.com/Neargye/magic_enum/archive/<commit>.zip"], )

To use bazel inside the repository it's possible to do:

bazel build //... bazel test //... bazel run //example

(Note that you must use a supported compiler or specify it with export CC= <compiler>.)

• If you are using Ros, you can include this package by adding <depend>magic_enum</depend> to your package.xml and include this package in your workspace. In your CMakeLists.txt add the following: cmake find_package(magic_enum CONFIG REQUIRED) ... target_link_libraries(your_executable magic_enum::magic_enum)

Compiler compatibility

• Clang/LLVM >= 5
• MSVC++ >= 14.11 / Visual Studio >= 2017
• Xcode >= 10
• GCC >= 9
• MinGW >= 9

Licensed under the MIT License