ceph/src/boost/libs/hana/include/boost/hana/symmetric_difference.hpp

   1 /*!
   2 @file
   3 Defines `boost::hana::symmetric_difference`.
   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_SYMMETRIC_DIFFERENCE_HPP
  11 #define BOOST_HANA_SYMMETRIC_DIFFERENCE_HPP
  12
  13 #include <boost/hana/fwd/symmetric_difference.hpp>
  14
  15 #include <boost/hana/config.hpp>
  16 #include <boost/hana/core/dispatch.hpp>
  17 #include <boost/hana/difference.hpp>
  18 #include <boost/hana/union.hpp>
  19
  20
  21 BOOST_HANA_NAMESPACE_BEGIN
  22     //! @cond
  23     template <typename Xs, typename Ys>
  24     constexpr auto symmetric_difference_t::operator()(Xs&& xs, Ys&& ys) const {
  25         using S = typename hana::tag_of<Xs>::type;
  26         using SymmetricDifference = BOOST_HANA_DISPATCH_IF(symmetric_difference_impl<S>,
  27             true
  28         );
  29
  30         return SymmetricDifference::apply(static_cast<Xs&&>(xs), static_cast<Ys&&>(ys));
  31     }
  32     //! @endcond
  33
  34     template <typename S, bool condition>
  35     struct symmetric_difference_impl<S, when<condition>> : default_ {
  36         template <typename Xs, typename Ys>
  37         static constexpr auto apply(Xs&& xs, Ys&& ys) {
  38             return hana::union_(
  39                 hana::difference(xs, ys),
  40                 hana::difference(ys, xs)
  41             );
  42         }
  43     };
  44 BOOST_HANA_NAMESPACE_END
  45
  46 #endif // !BOOST_HANA_SYMMETRIC_DIFFERENCE_HPP