enum_flags_name() can be constexpr, with returning static_string if enum is flag

[schaumb]

enum_flags_name() currently returns with std::string, which is can not be a constant expression.
Constexpr time can be calculated of the enum flags returning string maximum size (sum of all {enum name size} + count-1 for the separators).
This can be used as the result of the static_string template argument.

[ZXShady]

I am not a fan of this.

Yes, it could be theoritically constexpr but it isn't currently, also static_string would need to be a kind of static_vector so the size isn't messed up.

I would myself prefer this solution

1. Add another overload of

template<class E>
constexpr void enum_flags_name(char* data,E value);

then you can use function itself on a buffer of the size you want and get constexpr!

or

2. Make the returned string a template arguement (which is what I do in my library enchantum

template<class String = std::string,typename E>
constexpr String enum_flags_name(E value);

then users can replace String with their own constexpr alloc type

[Neargye]

@ZXShady second options can already be implemented using MAGIC_ENUM_USING_ALIAS_STRING

[ZXShady]

@ZXShady second options can already be implemented using MAGIC_ENUM_USING_ALIAS_STRING

This changes all strings though even if you only need it in a couple of places