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

   1 /*!
   2 @file
   3 Defines `boost::hana::Comonad`.
   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_COMONAD_HPP
  11 #define BOOST_HANA_CONCEPT_COMONAD_HPP
  12
  13 #include <boost/hana/fwd/concept/comonad.hpp>
  14
  15 #include <boost/hana/config.hpp>
  16 #include <boost/hana/core/default.hpp>
  17 #include <boost/hana/core/tag_of.hpp>
  18 #include <boost/hana/duplicate.hpp>
  19 #include <boost/hana/extend.hpp>
  20 #include <boost/hana/extract.hpp>
  21
  22
  23 BOOST_HANA_NAMESPACE_BEGIN
  24     template <typename W>
  25     struct Comonad {
  26         using Tag = typename tag_of<W>::type;
  27         static constexpr bool value = !is_default<extract_impl<Tag>>::value &&
  28                                       (!is_default<duplicate_impl<Tag>>::value ||
  29                                        !is_default<extend_impl<Tag>>::value);
  30     };
  31 BOOST_HANA_NAMESPACE_END
  32
  33 #endif // !BOOST_HANA_CONCEPT_COMONAD_HPP