Testing C++ metaprogramming

meta

#include <iostream>

template <typename T>
struct Identity
{
        typedef T result;
};
 
template <typename T, T v>
struct Constant
{
        typedef T type;
        static constexpr T value = v;
};
 
template <int N>
using Int = Constant<int, N>;

template <template<typename, typename> class fun, typename arg1>
struct bind
{
	template <typename arg2>
        struct result1 : fun<arg1, arg2>
        {};
};
 
template <typename left, typename right>
struct plus : Identity<Constant<decltype(left::value + right::value), left::value + right::value>>
{};
 
template <typename arg>
struct plus1 : bind<plus, Int<1>>::result1<arg>
{};
 
int main()
{
  std::cout << plus1<Int<100>>::result1::result::value << std::endl;
  std::cout << Int<101>::value << std::endl;
  std::cout << std::boolalpha << std::is_same<plus1<Int<100>>::result1::result, Int<101>>::value;
}