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 __anond0b37e580102(auto&& xs) 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 50