hashable.hpp 835 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/detail/integral_constant.hpp>
  16. #include <boost/hana/hash.hpp>
  17. BOOST_HANA_NAMESPACE_BEGIN
  18. template <typename T>
  19. struct Hashable
  20. : hana::integral_constant<bool,
  21. !is_default<hash_impl<typename tag_of<T>::type>>::value
  22. >
  23. { };
  24. BOOST_HANA_NAMESPACE_END
  25. #endif // !BOOST_HANA_CONCEPT_HASHABLE_HPP