CODEWITHSUNDEEP
c++c++11
Tamás Szelei
Tamás Szelei

Reputation: 23971

Is it possible to stringify enum values in C++11 without macros?

I know that it's possible to write a "register" macro that will map their values to their string representations. Is there however some new magic in C++11 that makes it possible to do without macros and any registration boilerplate?

To make it clear, I would like to be able to print the identifiers of enum variables, such as:

enum Days { Sunday, Monday, Tuesday };
auto d = Days::Sunday;
std::cout << magic << d;

Should output

Days::Sunday

Upvotes: 10

Views: 2114

Answers (3)

Moia
Moia

Reputation: 2364

As already told is not possible. But you can consider using a class as enum.

class Day
{
   enum _Day{ Sunday, Monday, Tuesday, Wensday, Thursday, Friday, Saturday }

public:
    static Day Sun;
    static Day Mon;
    static Day Tue;
    static Day Wen;
    static Day Thu;
    static Day Fri;
    static Day Sat;

    operator    int() const     { return _day; }

    int         toInt() const   { return _day; }
    std::string toStr() const   { return _name;}

private:
    Day(_Day day, std::string name) 
        : _day(day), _name(std::move(name))
    {
    }

  _Day _day;
  std::string _name;
};

Day Day::Mon = Day(_Day::Sun, "Sunday");
Day Day::Mon = Day(_Day::Mon, "Monday");

// ....

Stronger typing, works exactly like an enum, with the additional features you need.

Moreover you could add all the convenience functionality you could desire, for instance:

operator std::string() const;
bool operator==(const Day&);
Day& operator=(const Day&);

Upvotes: 0

Basile Starynkevitch
Basile Starynkevitch

Reputation: 1

No, this is not really possible. You need macros (preferably) or to extend the compiler for additional tricks (you might extend GCC with plugins or with MELT to provide a special _my_enum_name_builtin function, but I don't think it is a good idea). You could also (assuming the executable is built with debugging information kept) extract the name from debugging information.

If you really need that, a perhaps simpler way is to generate some (C++) code, which is nearly what macros are doing for you. The Qt Moc could be an inspiration for you.

Upvotes: 9

balki
balki

Reputation: 27684

No. Not possible without macros.

Upvotes: 2

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