policy.hpp

#ifndef ENTT_META_POLICY_HPP
#define ENTT_META_POLICY_HPP
 
#include <type_traits>
 
namespace entt {

namespace internal {
 
struct meta_policy {};
 
} // namespace internal

struct as_value_t final: private internal::meta_policy {
    template<typename>
    static constexpr bool value = true;
};

struct as_void_t final: private internal::meta_policy {
    template<typename>
    static constexpr bool value = true;
};

struct as_ref_t final: private internal::meta_policy {
    template<typename Type>
    static constexpr bool value = std::is_reference_v<Type> && !std::is_const_v<std::remove_reference_t<Type>>;
};

struct as_cref_t final: private internal::meta_policy {
    template<typename Type>
    static constexpr bool value = std::is_reference_v<Type>;
};

struct as_is_t final: private internal::meta_policy {
    template<typename>
    static constexpr bool value = true;
};

template<typename Type>
struct is_meta_policy
    : std::bool_constant<std::is_base_of_v<internal::meta_policy, Type>> {};

template<typename Type>
inline constexpr bool is_meta_policy_v = is_meta_policy<Type>::value;
 
} // namespace entt
 
#endif