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https://github.com/aantron/better-enums

C++ compile-time enum to string, iteration, in a single header file
https://github.com/aantron/better-enums

cpp enum header-only reflection

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C++ compile-time enum to string, iteration, in a single header file

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# Better Enums   [![Try online][wandbox-img]][wandbox] [![Travis status][travis-img]][travis] [![AppVeyor status][appveyor-img]][appveyor]



[wandbox]:      http://melpon.org/wandbox/permlink/2QCi3cwQnplAToge

[wandbox-img]:  https://img.shields.io/badge/try%20it-online-blue.svg

[appveyor]:     https://ci.appveyor.com/project/aantron/better-enums/branch/master

[travis]:       https://travis-ci.org/aantron/better-enums/branches

[travis-img]:   https://img.shields.io/travis/aantron/better-enums/master.svg?label=travis

[appveyor-img]: https://img.shields.io/appveyor/ci/aantron/better-enums/master.svg?label=appveyor

[license-img]:  https://img.shields.io/badge/license-BSD-lightgrey.svg



Reflective compile-time enum library with clean syntax, in a single header

file, and without dependencies.



![Better Enums code overview][sample]



[sample]: https://raw.githubusercontent.com/aantron/better-enums/master/doc/image/sample.gif



In C++11, *everything* can be used at compile time. You can convert your enums,

loop over them, [find their max][max],

[statically enforce conventions][enforce], and pass along the results as

template arguments or to `constexpr` functions. All the reflection is available

for your metaprogramming needs.



The interface is the same for C++98 — you just have to use most of it at

run time only. This library does provide scoped and sized enums, something not

built into C++98.



See the [project page][project] for full documentation.



[max]:      http://aantron.github.io/better-enums/demo/BitSets.html

[enforce]:  http://aantron.github.io/better-enums/demo/SpecialValues.html

[project]:  http://aantron.github.io/better-enums







## Installation



Simply add `enum.h` to your project.







## Additional features



- Uses only standard C++, though, for C++98, variadic macro support is required

  (major compilers have it).

- Supported and tested on [clang, gcc, and msvc][testing].

- Fast compilation. You have to declare a few dozen enums to slow down your

  compiler as much as [only including `iostream` does][performance].

- Use any initializers and sparse ranges, just like with a built-in enum.

- Control over size and alignment — you choose the representation type.

- Stream operators.

- Does not use the heap and can be compiled with exceptions disabled, for use in

  minimal freestanding environments.



[testing]:     http://aantron.github.io/better-enums/CompilerSupport.html

[performance]: http://aantron.github.io/better-enums/Performance.html







## Limitations



1. The biggest limitation is that the `BETTER_ENUM` macro can't be used inside a

class. This seems [difficult to remove][nested]. There is a workaround with

`typedef` (or C++11 `using`):



    ```c++

    BETTER_ENUM(SomePrefix_Color, uint8_t, Red, Green, Blue)



    struct triplet {

        typedef SomePrefix_Color    Color;

        Color                       r, g, b;

    };



    triplet::Color  color;

    ```



    You can, however, use `BETTER_ENUM` inside a namespace.



2. The macro has a soft limit of 64 declared constants. You can extend it by

following [these instructions][extend]. Ultimately, the number of constants is

limited by your compiler's maximum macro argument count.



3. In some cases, it is necessary to prefix constants such as `Channel::Red` with a

`+` to explicitly promote them to type `Channel`. For example, if you are doing

a comparison:



    ```c++

    channel == +Channel::Red

    ```



4. On msvc, you may need to enable [warning C4062][C4062] to get `switch` case exhaustiveness checking.



[nested]: http://aantron.github.io/better-enums/DesignDecisionsFAQ.html#NoEnumInsideClass

[extend]: http://aantron.github.io/better-enums/ExtendingLimits.html

[C4062]: https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-4-c4062







## History



The original version of the library was developed by the author in the winter of

2012-2013 at Hudson River Trading, as a replacement for an older generator

called `BETTER_ENUM`.