hashable.hpp 786 B

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