| /////////////////////////////////////////////////////////////////////////////// |
| /// \file utility.hpp |
| /// Proto callables for things found in the std \<utility\> header |
| // |
| // Copyright 2010 Eric Niebler. Distributed under the Boost |
| // Software License, Version 1.0. (See accompanying file |
| // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| |
| #ifndef BOOST_PROTO_FUNCTIONAL_STD_UTILITY_HPP_EAN_11_27_2010 |
| #define BOOST_PROTO_FUNCTIONAL_STD_UTILITY_HPP_EAN_11_27_2010 |
| |
| #include <utility> |
| #include <boost/type_traits/remove_const.hpp> |
| #include <boost/type_traits/remove_reference.hpp> |
| #include <boost/proto/proto_fwd.hpp> |
| |
| namespace boost { namespace proto { namespace functional |
| { |
| /// \brief A PolymorphicFunctionObject type that invokes the |
| /// \c std::make_pair() algorithm on its arguments. |
| /// |
| /// A PolymorphicFunctionObject type that invokes the |
| /// \c std::make_pair() algorithm on its arguments. |
| struct make_pair |
| { |
| BOOST_PROTO_CALLABLE() |
| |
| template<typename Sig> |
| struct result; |
| |
| template<typename This, typename First, typename Second> |
| struct result<This(First, Second)> |
| { |
| typedef |
| std::pair< |
| typename remove_const<typename remove_reference<First>::type>::type |
| , typename remove_const<typename remove_reference<Second>::type>::type |
| > |
| type; |
| }; |
| |
| template<typename First, typename Second> |
| std::pair<First, Second> operator()(First const &first, Second const &second) const |
| { |
| return std::make_pair(first, second); |
| } |
| }; |
| |
| /// \brief A PolymorphicFunctionObject type that returns |
| /// the first element of a std::pair. |
| /// |
| /// A PolymorphicFunctionObject type that returns |
| /// the first element of a std::pair.. |
| struct first |
| { |
| BOOST_PROTO_CALLABLE() |
| |
| template<typename Sig> |
| struct result; |
| |
| template<typename This, typename Pair> |
| struct result<This(Pair)> |
| { |
| typedef typename Pair::first_type type; |
| }; |
| |
| template<typename This, typename Pair> |
| struct result<This(Pair &)> |
| { |
| typedef typename Pair::first_type &type; |
| }; |
| |
| template<typename This, typename Pair> |
| struct result<This(Pair const &)> |
| { |
| typedef typename Pair::first_type const &type; |
| }; |
| |
| template<typename Pair> |
| typename Pair::first_type &operator()(Pair &pair) const |
| { |
| return pair.first; |
| } |
| |
| template<typename Pair> |
| typename Pair::first_type const &operator()(Pair const &pair) const |
| { |
| return pair.first; |
| } |
| }; |
| |
| /// \brief A PolymorphicFunctionObject type that returns |
| /// the second element of a std::pair. |
| /// |
| /// A PolymorphicFunctionObject type that returns |
| /// the second element of a std::pair.. |
| struct second |
| { |
| BOOST_PROTO_CALLABLE() |
| |
| template<typename Sig> |
| struct result; |
| |
| template<typename This, typename Pair> |
| struct result<This(Pair)> |
| { |
| typedef typename Pair::second_type type; |
| }; |
| |
| template<typename This, typename Pair> |
| struct result<This(Pair &)> |
| { |
| typedef typename Pair::second_type &type; |
| }; |
| |
| template<typename This, typename Pair> |
| struct result<This(Pair const &)> |
| { |
| typedef typename Pair::second_type const &type; |
| }; |
| |
| template<typename Pair> |
| typename Pair::second_type &operator()(Pair &pair) const |
| { |
| return pair.second; |
| } |
| |
| template<typename Pair> |
| typename Pair::second_type const &operator()(Pair const &pair) const |
| { |
| return pair.second; |
| } |
| }; |
| |
| }}} |
| |
| #endif |