//Purpose:
//  Test whether a placeholder is required
//  as one of template args to concept.
//
//Purpose:
//  Try various simple concepts to try and get
//  an idea of what's required of a concept.
//
#include <boost/type_erasure/any.hpp>
#include <boost/type_erasure/any_cast.hpp>
#include <boost/type_erasure/builtin.hpp>
#include <boost/type_erasure/operators.hpp>
#include <boost/mpl/vector.hpp>
#include <iostream>

namespace mpl = boost::mpl;
using namespace boost::type_erasure;
    typedef
  int
val_t;

//#define MODEL_DEFAULT_SELF
#ifdef MODEL_DEFAULT_SELF
#define MODEL_DEFAULT_TYPE _self
#else
#define MODEL_DEFAULT_TYPE val_t
#endif
  template
  < class Model=MODEL_DEFAULT_TYPE
  >
struct concept
{
        static
      void
    apply
      ( Model&model
      )
      {
          std::cout<<":apply("<<model<<" )\n";
      }
};

struct empty
{};
  std::ostream&
operator<<
  ( std::ostream& sout
  , empty const&
  )
  {
      sout<<"empty";
      return sout;
  }      

int main()
{
      empty
    a_empty;
      any
      < mpl::vector
        < copy_constructible<>
        , typeid_<>
        > 
      > 
    a_any(a_empty);
    empty e = any_cast<empty>(a_any);
    std::cout<<":e="<<e<<"\n";
    concept<> c;
  #ifndef MODEL_DEFAULT_SELF
    val_t y=999;
  #endif
    call
    ( c
  #ifdef MODEL_DEFAULT_SELF
    , a_any
  #else
    , y
  #endif
    );
    return 0;
}