auto_specification.hpp

#pragma once
#include <type_traits>

namespace compile_time {

namespace specification {
template <typename T> struct permitted_raw;
template <typename T>
inline constexpr bool is_permitted_raw =
    specification::permitted_raw<T>::value || std::is_arithmetic<T>::value;
} // namespace specification

namespace value {
template <bool, typename> struct default_convert;
template <typename T> struct default_convert<true, T> { using type = T; };
template <typename client> struct instance;
template <typename T> struct default_convert<false, T> {
  using type = instance<T>;
};
} // namespace value
namespace types {
template <typename, typename...> struct instance;
template <bool, typename> struct default_convert;
template <typename T> struct default_convert<true, T> { using type = T; };
template <typename T> struct default_convert<false, T> {
  template <typename... Fields> using type = instance<T, Fields...>;
};
} // namespace types
namespace specification {
template <typename T>
struct convert_to_instance
    : public value::default_convert<is_permitted_raw<T>, T> {};
template <typename T>
struct convert_to_type : public types::default_convert<is_permitted_raw<T>, T> {
};
template <typename T>
struct convert_to_instance<value::instance<T>> : public convert_to_instance<T> {
};
template <typename T>
struct convert_to_type<types::instance<T>> : public convert_to_type<T> {};
} // namespace specification
} // namespace compile_time