#include <iostream>
#include <boost/mpl/or.hpp>
#include <boost/mpl/has_xxx.hpp>

using namespace std;

namespace details
{
  BOOST_MPL_HAS_XXX_TRAIT_DEF(result_type)

  template< class F
          , template<class> class T = F::template result
          > struct has_result_impl
  {
    typedef void type;
  };

  template<class F, class EnableIf = void> struct has_result_struct : boost::false_type {};
  template<class F> struct has_result_struct<F,typename has_result_impl<F>::type> : boost::true_type {};
}

template<class F>
struct  support_result_of_protocol
      : boost::mpl::or_< details::has_result_type<F>
                       , details::has_result_struct<F>
                       >::type
{
};

struct nothing
{
};

struct has_a_result_type
{
    typedef void result_type;
};

struct has_a_result
{
    template<typename FArgs>
    struct result;

    template<typename T>
    struct result<has_a_result(T)>
    {
        typedef T** type;
    };
};

int main()
{
  cout << support_result_of_protocol<nothing>::value << endl;
  cout << support_result_of_protocol<has_a_result_type>::value << endl;
  cout << support_result_of_protocol<has_a_result>::value << endl;
}

false
true
true