[Preprocessor] Requirement about EnumToName

[T-rvw]

Define an enum can generate const char* GetXXXName(EnumType e) method automatically.

The first version I implemented is:

// Generate names for enum automatically.
#define DEFINE_ENUM_WITH_NAMES(EnumName, ...) \
	enum class EnumName { __VA_ARGS__, Count }; \
	constexpr std::array<const char*, static_cast<int>(EnumName::Count)> EnumName##Names = { #__VA_ARGS__ }; \
	constexpr const char* Get##EnumName##Name(EnumName enumValue) { return EnumName##Names[static_cast<int>(enumValue)]; }

But #__VA_ARGS__ will convert all enums to a single string. For example, Enum class Foo { A, B, C }; will get "A, B, C". So I need to split by comma in compile time or have a better preprocessor than macro.

After some searchs, I can use BOOST_PP_SEQ_FOR_EACH_I in boost. Or use static reflection lib about enum process such as https://github.com/Neargye/magic_enum.