README.md
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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Basic
#include <magic_enum/magic_enum.hpp>
#include <iostream>
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
Color color = Color::RED;
auto color_name = magic_enum::enum_name(color);
// color_name -> "RED"
String to enum value
std::string color_name{"GREEN"};
auto color = magic_enum::enum_cast<Color>(color_name);
if (color.has_value()) {
// color.value() -> Color::GREEN
}
// case insensitive enum_cast
auto color = magic_enum::enum_cast<Color>(value, magic_enum::case_insensitive);
// enum_cast with BinaryPredicate
auto color = magic_enum::enum_cast<Color>(value, [](char lhs, char rhs) { return std::tolower(lhs) == std::tolower(rhs); });
// enum_cast with default
auto color_or_default = magic_enum::enum_cast<Color>(value).value_or(Color::NONE);
Integer to enum value
int color_integer = 0;
auto color = magic_enum::enum_cast<Color>(color_integer);
if (color.has_value()) {
// color.value() -> Color::BLUE
}
auto color_or_default = magic_enum::enum_cast<Color>(value).value_or(Color::NONE);
Indexed access to enum value
std::size_t i = 0;
Color color = magic_enum::enum_value<Color>(i);
// color -> Color::RED
Enum value sequence
constexpr auto colors = magic_enum::enum_values<Color>();
// colors -> {Color::RED, Color::BLUE, Color::GREEN}
// colors[0] -> Color::RED
Number of enum elements
constexpr std::size_t color_count = magic_enum::enum_count<Color>();
// color_count -> 3
Enum value to integer
Color color = Color::RED;
auto color_integer = magic_enum::enum_integer(color); // or magic_enum::enum_underlying(color);
// color_integer -> -10
Enum names sequence
constexpr auto color_names = magic_enum::enum_names<Color>();
// color_names -> {"RED", "BLUE", "GREEN"}
// color_names[0] -> "RED"
Enum entries sequence
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
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
Color color = Color::RED;
magic_enum::enum_switch([] (auto val) {
constexpr Color c_color = val;
// ...
}, color);
Enum iterate for each enum as constexpr constant
magic_enum::enum_for_each<Color>([] (auto val) {
constexpr Color c_color = val;
// ...
});
Check if enum contains
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
constexpr auto color_index = magic_enum::enum_index(Color::BLUE);
// color_index.value() -> 1
// color_index.has_value() -> true
Functions for flags
enum Directions : std::uint64_t {
Left = 1,
Down = 2,
Up = 4,
Right = 8,
};
template <>
struct magic_enum::customize::enum_range<Directions> {
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<Directions>("Left,Down", ','); // -> Directions::Left|Directions::Down
Enum type name
Color color = Color::RED;
auto type_name = magic_enum::enum_type_name<decltype(color)>();
// type_name -> "Color"
IOstream operator for enum
using magic_enum::iostream_operators::operator<<; // out-of-the-box ostream operators for enums.
Color color = Color::BLUE;
std::cout << color << std::endl; // "BLUE"
using magic_enum::iostream_operators::operator>>; // out-of-the-box istream operators for enums.
Color color;
std::cin >> color;
Bitwise operator for enum
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.
enum color { red, green, blue };
enum class direction { left, right };
magic_enum::is_unscoped_enum<color>::value -> true
magic_enum::is_unscoped_enum<direction>::value -> false
magic_enum::is_unscoped_enum<int>::value -> false
// Helper variable template.
magic_enum::is_unscoped_enum_v<color> -> true
Checks whether type is an Scoped enumeration.
enum color { red, green, blue };
enum class direction { left, right };
magic_enum::is_scoped_enum<color>::value -> false
magic_enum::is_scoped_enum<direction>::value -> true
magic_enum::is_scoped_enum<int>::value -> false
// Helper variable template.
magic_enum::is_scoped_enum_v<direction> -> 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.
constexpr Color color = Color::BLUE;
constexpr auto color_name = magic_enum::enum_name<color>();
// color_name -> "BLUE"
containers::array array container for enums.
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.
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.
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.
magic_enum::underlying_type<color>::type -> int
// Helper types.
magic_enum::underlying_type_t<Direction> -> int
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.
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.
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:
find_package(magic_enum CONFIG REQUIRED)
...
target_link_libraries(your_executable magic_enum::magic_enum)