enum to string in modern C++11 / C++14 / C++17 and future C++20

Question

Contrary to all other similar questions, this question is about using the new C++ features.

• 2008 c Is there a simple way to convert C++ enum to string?
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Answer 1

Very simple solution with one big constraint: you can't assign custom values to enum values, but with the right regex, you could. you could also add a map to translate them back to enum values without much more effort:

#include 
#include 
#include 
#include 

std::vector split(const std::string& s, 
                               const std::regex& delim = std::regex(",\\s*"))
{
    using namespace std;
    vector cont;
    copy(regex_token_iterator(s.begin(), s.end(), delim, -1), 
         regex_token_iterator(),
         back_inserter(cont));
    return cont;
}

#define EnumType(Type, ...)     enum class Type { __VA_ARGS__ }

#define EnumStrings(Type, ...)  static const std::vector \
                                Type##Strings = split(#__VA_ARGS__);

#define EnumToString(Type, ...) EnumType(Type, __VA_ARGS__); \
                                EnumStrings(Type, __VA_ARGS__)

Usage example:

EnumToString(MyEnum, Red, Green, Blue);