ceph/src/boost/libs/hana/include/boost/hana/concept/metafunction.hpp

   1 /*!
   2 @file
   3 Defines `boost::hana::Metafunction`.
   4
   5 @copyright Louis Dionne 2013-2016
   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
  10 #ifndef BOOST_HANA_CONCEPT_METAFUNCTION_HPP
  11 #define BOOST_HANA_CONCEPT_METAFUNCTION_HPP
  12
  13 #include <boost/hana/fwd/concept/metafunction.hpp>
  14
  15 #include <boost/hana/config.hpp>
  16 #include <boost/hana/core/tag_of.hpp>
  17
  18
  19 BOOST_HANA_NAMESPACE_BEGIN
  20     namespace detail {
  21         template <typename F, typename Tag = typename tag_of<F>::type>
  22         struct metafunction_dispatch {
  23             static constexpr bool value = Metafunction<Tag>::value;
  24         };
  25
  26         template <typename F>
  27         struct metafunction_dispatch<F, F> {
  28             static constexpr bool value = false;
  29         };
  30     }
  31
  32     template <typename F>
  33     struct Metafunction
  34         : detail::metafunction_dispatch<F>
  35     { };
  36 BOOST_HANA_NAMESPACE_END
  37
  38 #endif // !BOOST_HANA_CONCEPT_METAFUNCTION_HPP