ceph/src/boost/boost/hana/fwd/reverse.hpp

   1 /*!
   2 @file
   3 Forward declares `boost::hana::reverse`.
   4
   5 @copyright Louis Dionne 2013-2017
   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_FWD_REVERSE_HPP
  11 #define BOOST_HANA_FWD_REVERSE_HPP
  12
  13 #include <boost/hana/config.hpp>
  14 #include <boost/hana/core/when.hpp>
  15
  16
  17 BOOST_HANA_NAMESPACE_BEGIN
  18     //! Reverse a sequence.
  19     //! @ingroup group-Sequence
  20     //!
  21     //! Specifically, `reverse(xs)` is a new sequence containing the same
  22     //! elements as `xs`, except in reverse order.
  23     //!
  24     //!
  25     //! @param xs
  26     //! The sequence to reverse.
  27     //!
  28     //!
  29     //! Example
  30     //! -------
  31     //! @include example/reverse.cpp
  32 #ifdef BOOST_HANA_DOXYGEN_INVOKED
  33     constexpr auto reverse = [](auto&& xs) {
  34         return tag-dispatched;
  35     };
  36 #else
  37     template <typename S, typename = void>
  38     struct reverse_impl : reverse_impl<S, when<true>> { };
  39
  40     struct reverse_t {
  41         template <typename Xs>
  42         constexpr auto operator()(Xs&& xs) const;
  43     };
  44
  45     constexpr reverse_t reverse{};
  46 #endif
  47 BOOST_HANA_NAMESPACE_END
  48
  49 #endif // !BOOST_HANA_FWD_REVERSE_HPP