287 lines
9.4 KiB
Markdown
287 lines
9.4 KiB
Markdown
[](https://bit.ly/3OMysM8)
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```text
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__ __ _ ______ _____
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| \/ | (_) | ____| / ____|_ _
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| \ / | __ _ __ _ _ ___ | |__ _ __ _ _ _ __ ___ | | _| |_ _| |_
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| |\/| |/ _` |/ _` | |/ __| | __| | '_ \| | | | '_ ` _ \ | | |_ _|_ _|
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| | | | (_| | (_| | | (__ | |____| | | | |_| | | | | | | | |____|_| |_|
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|_| |_|\__,_|\__, |_|\___| |______|_| |_|\__,_|_| |_| |_| \_____|
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__/ |
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|___/
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```
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[](https://github.com/Neargye/magic_enum/releases)
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[](https://conan.io/center/magic_enum)
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[](https://github.com/microsoft/vcpkg/tree/master/ports/magic-enum)
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[](https://www.cppget.org/magic_enum?q=magic_enum)
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[](LICENSE)
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[](https://wandbox.org/permlink/JPMZqT9mgaUdooyC)
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[](https://godbolt.org/z/BxfmsH)
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# Magic Enum C++
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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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* `enum_cast` obtains enum value from string or integer.
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* `enum_value` returns enum value at specified index.
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* `enum_values` obtains enum value sequence.
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* `enum_count` returns number of enum values.
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* `enum_integer` obtains integer value from enum value.
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* `enum_name` returns name from enum value.
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* `enum_names` obtains string enum name sequence.
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* `enum_entries` obtains pair (value enum, string enum name) sequence.
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* `enum_index` obtains index in enum value sequence from enum value.
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* `enum_contains` checks whether enum contains enumerator with such value.
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* `enum_type_name` returns name of enum type.
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* `enum_fuse` allows multidimensional switch/cases.
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* `enum_switch` allows runtime enum value transformation to constexpr context.
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* `enum_for_each` calls a function with all enum constexpr value.
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* `is_unscoped_enum` checks whether type is an [Unscoped enumeration](https://en.cppreference.com/w/cpp/language/enum#Unscoped_enumeration).
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* `is_scoped_enum` checks whether type is an [Scoped enumeration](https://en.cppreference.com/w/cpp/language/enum#Scoped_enumerations).
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* `underlying_type` improved UB-free "SFINAE-friendly" [underlying_type](https://en.cppreference.com/w/cpp/types/underlying_type).
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* `ostream_operators` ostream operators for enums.
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* `bitwise_operators` bitwise operators for enums.
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## Documentation
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* [Reference](doc/reference.md)
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* [Limitations](doc/limitations.md)
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* [Integration](#Integration)
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## Features
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* C++17
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* Header-only
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* Dependency-free
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* Compile-time
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* Enum to string
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* String to enum
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* Iterating over enum
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## [Examples](example/example.cpp)
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* Enum value to string
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```cpp
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Color color = Color::RED;
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auto color_name = magic_enum::enum_name(color);
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// color_name -> "RED"
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```
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* String to enum value
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```cpp
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std::string color_name{"GREEN"};
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auto color = magic_enum::enum_cast<Color>(color_name);
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if (color.has_value()) {
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// color.value() -> Color::GREEN
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}
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auto color_or_default = magic_enum::enum_cast<Color>(value).value_or(Color::NONE);
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```
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* Integer to enum value
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```cpp
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int color_integer = 2;
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auto color = magic_enum::enum_cast<Color>(color_integer);
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if (color.has_value()) {
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// color.value() -> Color::BLUE
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}
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auto color_or_default = magic_enum::enum_cast<Color>(value).value_or(Color::NONE);
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```
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* Indexed access to enum value
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```cpp
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std::size_t i = 0;
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Color color = magic_enum::enum_value<Color>(i);
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// color -> Color::RED
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```
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* Enum value sequence
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```cpp
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constexpr auto colors = magic_enum::enum_values<Color>();
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// colors -> {Color::RED, Color::BLUE, Color::GREEN}
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// colors[0] -> Color::RED
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```
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* Number of enum elements
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```cpp
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constexpr std::size_t color_count = magic_enum::enum_count<Color>();
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// color_count -> 3
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```
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* Enum value to integer
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```cpp
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Color color = Color::RED;
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auto color_integer = magic_enum::enum_integer(color);
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// color -> 1
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```
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* Enum names sequence
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```cpp
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constexpr auto color_names = magic_enum::enum_names<Color>();
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// color_names -> {"RED", "BLUE", "GREEN"}
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// color_names[0] -> "RED"
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```
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* Enum entries sequence
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```cpp
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constexpr auto color_entries = magic_enum::enum_entries<Color>();
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// color_entries -> {{Color::RED, "RED"}, {Color::BLUE, "BLUE"}, {Color::GREEN, "GREEN"}}
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// color_entries[0].first -> Color::RED
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// color_entries[0].second -> "RED"
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```
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* Enum fusion for multi-level switch/case statements
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```cpp
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switch (magic_enum::enum_fuse(color, direction).value()) {
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case magic_enum::enum_fuse(Color::RED, Directions::Up).value(): // ...
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case magic_enum::enum_fuse(Color::BLUE, Directions::Down).value(): // ...
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// ...
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}
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```
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* Enum switch runtime value as constexpr constant
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```cpp
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Color color = Color::RED;
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magic_enum::enum_switch([] (auto val) {
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constexpr Color c_color = val;
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// ...
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}, color);
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```
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* Enum iterate for each enum as constexpr constant
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```cpp
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magic_enum::enum_for_each<Color>([] (auto val) {
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constexpr Color c_color = val;
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// ...
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});
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```
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* Ostream operator for enum
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```cpp
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using namespace magic_enum::ostream_operators; // out-of-the-box ostream operators for enums.
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Color color = Color::BLUE;
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std::cout << color << std::endl; // "BLUE"
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```
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* Bitwise operator for enum
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```cpp
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enum class Flags { A = 1 << 0, B = 1 << 1, C = 1 << 2, D = 1 << 3 };
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using namespace magic_enum::bitwise_operators; // out-of-the-box bitwise operators for enums.
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// Support operators: ~, |, &, ^, |=, &=, ^=.
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Flags flags = Flags::A | Flags::B & ~Flags::C;
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```
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* Checks whether type is an [Unscoped enumeration](https://en.cppreference.com/w/cpp/language/enum#Unscoped_enumeration).
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```cpp
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enum color { red, green, blue };
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enum class direction { left, right };
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magic_enum::is_unscoped_enum<color>::value -> true
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magic_enum::is_unscoped_enum<direction>::value -> false
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magic_enum::is_unscoped_enum<int>::value -> false
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// Helper variable template.
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magic_enum::is_unscoped_enum_v<color> -> true
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```
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* Checks whether type is an [Scoped enumeration](https://en.cppreference.com/w/cpp/language/enum#Scoped_enumerations).
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```cpp
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enum color { red, green, blue };
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enum class direction { left, right };
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magic_enum::is_scoped_enum<color>::value -> false
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magic_enum::is_scoped_enum<direction>::value -> true
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magic_enum::is_scoped_enum<int>::value -> false
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// Helper variable template.
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magic_enum::is_scoped_enum_v<direction> -> true
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```
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* Static storage enum variable to string
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This version is much lighter on the compile times and is not restricted to the enum_range [limitation](doc/limitations.md).
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```cpp
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constexpr Color color = Color::BLUE;
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constexpr auto color_name = magic_enum::enum_name<color>();
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// color_name -> "BLUE"
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```
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## Remarks
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* `magic_enum` does not pretend to be a silver bullet for reflection for enums, it was originally designed for small enum.
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* Before use, read the [limitations](doc/limitations.md) of functionality.
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## Integration
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* You should add the required file [magic_enum.hpp](include/magic_enum.hpp).
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* If you are using [vcpkg](https://github.com/Microsoft/vcpkg/) on your project for external dependencies, then you can use the [magic-enum package](https://github.com/microsoft/vcpkg/tree/master/ports/magic-enum).
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* If you are using [Conan](https://www.conan.io/) 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.
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* If you are using [Build2](https://build2.org/) 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}`.
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* Alternatively, you can use something like [CPM](https://github.com/TheLartians/CPM) which is based on CMake's `Fetch_Content` module.
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```cmake
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CPMAddPackage(
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NAME magic_enum
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GITHUB_REPOSITORY Neargye/magic_enum
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GIT_TAG x.y.z # Where `x.y.z` is the release version you want to use.
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)
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```
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* Bazel is also supported, simply add to your WORKSPACE file:
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```
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http_archive(
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name = "magic_enum",
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strip_prefix = "magic_enum-<commit>",
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urls = ["https://github.com/Neargye/magic_enum/archive/<commit>.zip"],
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)
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```
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To use bazel inside the repository it's possible to do:
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```
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bazel build //...
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bazel test //...
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bazel run //:example
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```
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(Note that you must use a supported compiler or specify it with `export CC= <compiler>`.)
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* If you are using [Ros](https://www.ros.org/), 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:
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```cmake
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find_package(magic_enum CONFIG REQUIRED)
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...
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target_link_libraries(your_executable magic_enum::magic_enum)
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```
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## Compiler compatibility
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* Clang/LLVM >= 6
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* MSVC++ >= 14.11 / Visual Studio >= 2017
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* Xcode >= 10
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* GCC >= 9
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* MinGW >= 9
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## Licensed under the [MIT License](LICENSE)
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