C++ Template for mapping struct type to enum?

Question

I have something like:

struct A { ... };
struct B { ... };
struct C { ... };

class MyEnum {
public:
    enum Value { a, b, c; }
}

template

        

Answer 1

The multiple definitions are because you need to either add the inline keyword or push the implementation of your specializations into a cpp file, leaving only the declarations of such in the header.

You could probably use mpl::map to write a sort-of generic version. Something like so:

struct A {};
struct B {};
struct C {};

enum Value { a,b,c };

template < typename T >
Value get_value()
{
  using namespace boost::mpl;
  typedef mpl::map
  < 
    mpl::pair< A, mpl::int_ >
  , mpl::pair< B, mpl::int_ >
  , mpl::pair< C, mpl::int_ >
  > type_enum_map;

  typedef typename mpl::at::type enum_wrap_type;

  return static_cast(enum_wrap_type::value);
}