Find a kernel that is not the Dummy_kernel

Kernel_traits_N.cpp

#include <type_traits>
#include <typeinfo>
#include <iostream>


template <typename T>
struct Dummy
{};


struct Cartesian
{};

struct Point
{};

struct Number
{};

template <typename T>
struct Kernel_traits
{
  typedef Dummy<T> type;
};

template <>
struct Kernel_traits<Point>
{
  typedef Cartesian type;
};



template <typename... T>
struct Kernel_traits_N {
  typedef int type;
};



template<
            typename T,
            typename... Rest
        >
struct Kernel_traits_N<T, Rest...> {

  typedef typename std::conditional<std::is_same<Dummy<T>, typename Kernel_traits<T>::type>::value,
                           typename Kernel_traits_N<Rest...>::type,
                           typename Kernel_traits<T>::type>::type type;
};


int main()
{
  typedef Kernel_traits_N<char, Point, Number>::type T;

  std::cout << typeid(T).name()  << std::endl;
  return 0;
}