Is it possible to manually define a conversion for an enum class?

Question

Normally you can define a cast for a class by using the following syntax:

class Test {
public:
  explicit operator bool() { return false; }
};

Answer 1

You cant define non-member cast operators in C++. And you certainly cant define member functions for enums. So I suggest you do free functions to convert your enum to other types, the same way you would implement cast operators.

e.g.

bool TestToBool(enum_e val)
{
    return false;
}

const char *TestToString(enum_e val)
{
    return "false";
}

---

There is a nice way of associating those enums to bools, you have to split it on two files .h and .cpp. Here it is if it helps:

enum.h

///////////////////////////////
// enum.h
#ifdef CPP_FILE
#define ENUMBOOL_ENTRY(A, B)            { (enum_e) A, (bool) B },
struct EnumBool
{
    enum_e  enumVal;
    bool    boolVal;
};
#else
#define ENUMBOOL_ENTRY(A, B)            A,
#endif


#ifdef CPP_FILE
static EnumBool enumBoolTable[] = {
#else
enum enum_e
{
#endif
ENUMBOOL_ENTRY(ItemA, true),
ENUMBOOL_ENTRY(ItemB, false),
...
};

bool EnumToBool(enum_e val);

enum.cpp

///////////////////////////////
// enum.cpp
#define CPP_FILE
#include "enum.h"

bool EnumToBool(enum_e val)
    //implement

I didnt compile it so take it easy if it has any errors :).