Re: Trying to apply SFINAE

Kai-Uwe Bux wrote:


   In my case it's even simpler, since I don't need the meta-function.
   Here's what I came up with while commuting this morning:

     struct yes_type { char dummy; };
     struct no_type { char dummy1; char dummy2; };

     template < typename T >
     yes_type is_iterator(const T&, typename T::iterator_category* = 0)
     {return yes_type();}

     template < typename T >
     yes_type is_iterator(const T* const)
     {return yes_type();}

     no_type is_iterator(const void* const)
     {return no_type();}

     no_type is_iterator(...)
     {return no_type();}

     #include <iostream>
     #include <vector>

     template < typename T >
     inline void show( const T&, yes_type /*is_iterator*/)
     {std::cout << "iterator: ";}

     template < typename T >
     inline void show( const T&, no_type /*is_iterator*/)
     {std::cout << "no iterator: ";}

     template < typename T >
     inline void show(const char* str) {
         show( T(), typename is_iterator(T()) );
         std::cout << str << '\n';
     }

     #define SHOW(T) show<T>(#T)

     int main() {
         SHOW( int* );
         SHOW( int** );
         SHOW( int* const* );
         SHOW( const int* );
         SHOW( const int** );
         SHOW( const int* const* );
         SHOW( std::vector<int>::const_iterator );
         std::cout << '\n';
         SHOW( void* );
         SHOW( std::vector<int> );
         SHOW( int );
     }

   However, this still needs a forwarding function... <sighs>


  Schobi