impl/Morpheus_Metaprogramming.hpp

 
#ifndef MORPHEUS_IMPL_METAPROGRAMMING_HPP
#define MORPHEUS_IMPL_METAPROGRAMMING_HPP
 
namespace Morpheus {
 
// Forward declarations
template <typename... Ts>
struct TypeList;
template <typename... Ts>
struct Set;
template <class... Ts>
struct IndexedTypeList;
 
template <typename T, typename U>
struct cross_product;
template <typename... T>
struct concat;
 
namespace Impl {
// forward decl
template <typename T, typename U>
struct cross_product;
template <typename... T>
struct concat;
 
template <typename... Ts, typename... Us>
struct concat<TypeList<Ts...>, TypeList<Us...>> {
  using type = TypeList<Ts..., Us...>;
};
 
// Partially specialise the empty cases.
template <typename... Us>
struct cross_product<TypeList<>, TypeList<Us...>> {
  using type = TypeList<>;
};
 
template <typename... Us>
struct cross_product<TypeList<Us...>, TypeList<>> {
  using type = TypeList<>;
};
 
template <>
struct cross_product<TypeList<>, TypeList<>> {
  using type = TypeList<>;
};
 
// Generic Case
template <typename T, typename... Ts, typename U, typename... Us>
struct cross_product<TypeList<T, Ts...>, TypeList<U, Us...>> {
  using type = typename concat<
      typename concat<
          TypeList<Set<T, U>>,
          typename cross_product<TypeList<T>, TypeList<Us...>>::type>::type,
      typename cross_product<TypeList<Ts...>, TypeList<U, Us...>>::type>::type;
};
 
template <typename... T, typename... Ts, typename U, typename... Us>
struct cross_product<TypeList<Set<T...>, Ts...>, TypeList<U, Us...>> {
  using type = typename concat<
      typename concat<TypeList<Set<T..., U>>,
                      typename cross_product<TypeList<Set<T...>>,
                                             TypeList<Us...>>::type>::type,
      typename cross_product<TypeList<Ts...>, TypeList<U, Us...>>::type>::type;
};
 
template <typename T, typename... Ts, typename... U, typename... Us>
struct cross_product<TypeList<T, Ts...>, TypeList<Set<U...>, Us...>> {
  using type = typename concat<
      typename concat<
          TypeList<Set<T, U...>>,
          typename cross_product<TypeList<T>, TypeList<Us...>>::type>::type,
      typename cross_product<TypeList<Ts...>,
                             TypeList<Set<U...>, Us...>>::type>::type;
};
 
template <typename... T, typename... Ts, typename... U, typename... Us>
struct cross_product<TypeList<Set<T...>, Ts...>, TypeList<Set<U...>, Us...>> {
  using type = typename concat<
      typename concat<TypeList<Set<T..., U...>>,
                      typename cross_product<TypeList<Set<T...>>,
                                             TypeList<Us...>>::type>::type,
      typename cross_product<TypeList<Ts...>,
                             TypeList<Set<U...>, Us...>>::type>::type;
};
}  // namespace Impl
}  // namespace Morpheus
#endif  // MORPHEUS_IMPL_METAPROGRAMMING_HPP