projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | /*! |
| 2 | @file | |
| 3 | Adapts `std::pair` for use with Hana. | |
| 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_EXT_STD_PAIR_HPP | |
| 11 | #define BOOST_HANA_EXT_STD_PAIR_HPP | |
| 12 | ||
| 13 | #include <boost/hana/config.hpp> | |
| 14 | #include <boost/hana/fwd/core/make.hpp> | |
| 15 | #include <boost/hana/fwd/core/tag_of.hpp> | |
| 16 | #include <boost/hana/fwd/first.hpp> | |
| 17 | #include <boost/hana/fwd/second.hpp> | |
| 18 | ||
| 19 | #include <utility> | |
| 20 | ||
| 21 | ||
| 22 | #ifdef BOOST_HANA_DOXYGEN_INVOKED | |
| 23 | namespace std { | |
| 24 | //! @ingroup group-ext-std | |
| 25 | //! Adaptation of `std::pair` for Hana. | |
| 26 | //! | |
| 27 | //! | |
| 28 | //! Modeled concepts | |
| 29 | //! ---------------- | |
| 30 | //! A `std::pair` models exactly the same concepts as a `hana::pair`. | |
| 31 | //! Please refer to the documentation of `hana::pair` for details. | |
| 32 | //! | |
| 33 | //! @include example/ext/std/pair.cpp | |
| 34 | template <typename First, typename Second> | |
| 35 | struct pair { }; | |
| 36 | } | |
| 37 | #endif | |
| 38 | ||
| 39 | ||
| 40 | BOOST_HANA_NAMESPACE_BEGIN | |
| 41 | namespace ext { namespace std { struct pair_tag; }} | |
| 42 | ||
| 43 | template <typename First, typename Second> | |
| 44 | struct tag_of<std::pair<First, Second>> { | |
| 45 | using type = ext::std::pair_tag; | |
| 46 | }; | |
| 47 | ||
| 48 | ////////////////////////////////////////////////////////////////////////// | |
| 49 | // Product | |
| 50 | ////////////////////////////////////////////////////////////////////////// | |
| 51 | template <> | |
| 52 | struct make_impl<ext::std::pair_tag> { | |
| 53 | template <typename X, typename Y> | |
| 54 | static constexpr decltype(auto) apply(X&& x, Y&& y) { | |
| 55 | return std::make_pair(static_cast<X&&>(x), | |
| 56 | static_cast<Y&&>(y)); | |
| 57 | } | |
| 58 | }; | |
| 59 | ||
| 60 | template <> | |
| 61 | struct first_impl<ext::std::pair_tag> { | |
| 62 | template <typename T, typename U> | |
| 63 | static constexpr T const& apply(std::pair<T, U> const& p) | |
| 64 | { return p.first; } | |
| 65 | ||
| 66 | template <typename T, typename U> | |
| 67 | static constexpr T& apply(std::pair<T, U>& p) | |
| 68 | { return p.first; } | |
| 69 | ||
| 70 | template <typename T, typename U> | |
| 71 | static constexpr T&& apply(std::pair<T, U>&& p) | |
| 72 | { return static_cast<T&&>(p.first); } | |
| 73 | }; | |
| 74 | ||
| 75 | template <> | |
| 76 | struct second_impl<ext::std::pair_tag> { | |
| 77 | template <typename T, typename U> | |
| 78 | static constexpr U const& apply(std::pair<T, U> const& p) | |
| 79 | { return p.second; } | |
| 80 | ||
| 81 | template <typename T, typename U> | |
| 82 | static constexpr U& apply(std::pair<T, U>& p) | |
| 83 | { return p.second; } | |
| 84 | ||
| 85 | template <typename T, typename U> | |
| 86 | static constexpr U&& apply(std::pair<T, U>&& p) | |
| 87 | { return static_cast<U&&>(p.second); } | |
| 88 | }; | |
| 89 | BOOST_HANA_NAMESPACE_END | |
| 90 | ||
| 91 | #endif // !BOOST_HANA_EXT_STD_PAIR_HPP |