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

   1 /*!
   2 @file
   3 Defines `boost::hana::fuse`.
   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_FUSE_HPP
  11 #define BOOST_HANA_FUSE_HPP
  12
  13 #include <boost/hana/fwd/fuse.hpp>
  14
  15 #include <boost/hana/config.hpp>
  16 #include <boost/hana/detail/decay.hpp>
  17 #include <boost/hana/unpack.hpp>
  18
  19
  20 BOOST_HANA_NAMESPACE_BEGIN
  21     namespace detail {
  22         template <typename F>
  23         struct fused {
  24             F f;
  25             template <typename Xs>
  26             constexpr decltype(auto) operator()(Xs&& xs) const&
  27             { return hana::unpack(static_cast<Xs&&>(xs), f); }
  28
  29             template <typename Xs>
  30             constexpr decltype(auto) operator()(Xs&& xs) &
  31             { return hana::unpack(static_cast<Xs&&>(xs), f); }
  32
  33             template <typename Xs>
  34             constexpr decltype(auto) operator()(Xs&& xs) &&
  35             { return hana::unpack(static_cast<Xs&&>(xs), static_cast<F&&>(f)); }
  36         };
  37     }
  38
  39     //! @cond
  40     template <typename F>
  41     constexpr auto fuse_t::operator()(F&& f) const {
  42         return detail::fused<typename detail::decay<F>::type>{static_cast<F&&>(f)};
  43     }
  44     //! @endcond
  45 BOOST_HANA_NAMESPACE_END
  46
  47 #endif // !BOOST_HANA_FUSE_HPP