hana/concept/hashable.hpp

0001 /*!
0002 @file
0003 Defines `boost::hana::Hashable`.
0004
0005 Copyright Louis Dionne 2016
0006 Copyright Jason Rice 2016
0007 Distributed under the Boost Software License, Version 1.0.
0008 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
0009  */
0010
0011 #ifndef BOOST_HANA_CONCEPT_HASHABLE_HPP
0012 #define BOOST_HANA_CONCEPT_HASHABLE_HPP
0013
0014 #include <boost/hana/fwd/concept/hashable.hpp>
0015
0016 #include <boost/hana/config.hpp>
0017 #include <boost/hana/core/default.hpp>
0018 #include <boost/hana/core/tag_of.hpp>
0019 #include <boost/hana/detail/integral_constant.hpp>
0020 #include <boost/hana/hash.hpp>
0021
0022
0023 namespace boost { namespace hana {
0024     template <typename T>
0025     struct Hashable
0026         : hana::integral_constant<bool,
0027             !is_default<hash_impl<typename tag_of<T>::type>>::value
0028         >
0029     { };
0030 }} // end namespace boost::hana
0031
0032 #endif // !BOOST_HANA_CONCEPT_HASHABLE_HPP