Template metaprogram converting type to unique number

Question

I just started playing with metaprogramming and I am working on different tasks just to explore the domain. One of these was to generate a unique integer and map it to type,

Answer 1

type2int as compile time constant is impossible even in C++11. Maybe some rich guy should promise a reward for the anwser? Until then I'm using the following solution, which is basically equal to Matthew Herrmann's:

class type2intbase {
    template 
    friend struct type2int;

    static const int next() {
        static int id = 0; return id++;
    }
};

template 
struct type2int {
    static const int value() {
        static const int id = type2intbase::next(); return id;
    }
};

Note also

template 
struct type2ptr {
    static const void* const value() {
        return typeid(T).name();
    }
};