1 /*! 2 @file 3 Defines `boost::hana::Hashable`. 4 5 @copyright Louis Dionne 2016 6 @copyright Jason Rice 2016 7 Distributed under the Boost Software License, Version 1.0. 8 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) 9 */ 10 11 #ifndef BOOST_HANA_CONCEPT_HASHABLE_HPP 12 #define BOOST_HANA_CONCEPT_HASHABLE_HPP 13 14 #include <boost/hana/fwd/concept/hashable.hpp> 15 16 #include <boost/hana/config.hpp> 17 #include <boost/hana/core/default.hpp> 18 #include <boost/hana/core/tag_of.hpp> 19 #include <boost/hana/detail/integral_constant.hpp> 20 #include <boost/hana/hash.hpp> 21 22 23 BOOST_HANA_NAMESPACE_BEGIN 24 template <typename T> 25 struct Hashable 26 : hana::integral_constant<bool, 27 !is_default<hash_impl<typename tag_of<T>::type>>::value 28 > 29 { }; 30 BOOST_HANA_NAMESPACE_END 31 32 #endif // !BOOST_HANA_CONCEPT_HASHABLE_HPP 33