Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: /// \file utility.hpp
Chris@16: /// Proto callables for things found in the std \<utility\> header
Chris@16: //
Chris@16: //  Copyright 2010 Eric Niebler. Distributed under the Boost
Chris@16: //  Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_PROTO_FUNCTIONAL_STD_UTILITY_HPP_EAN_11_27_2010
Chris@16: #define BOOST_PROTO_FUNCTIONAL_STD_UTILITY_HPP_EAN_11_27_2010
Chris@16: 
Chris@16: #include <utility>
Chris@16: #include <boost/type_traits/remove_const.hpp>
Chris@16: #include <boost/type_traits/remove_reference.hpp>
Chris@16: #include <boost/proto/proto_fwd.hpp>
Chris@16: 
Chris@16: namespace boost { namespace proto { namespace functional
Chris@16: {
Chris@16:     /// \brief A PolymorphicFunctionObject type that invokes the
Chris@16:     /// \c std::make_pair() algorithm on its arguments.
Chris@16:     ///
Chris@16:     /// A PolymorphicFunctionObject type that invokes the
Chris@16:     /// \c std::make_pair() algorithm on its arguments.
Chris@16:     struct make_pair
Chris@16:     {
Chris@16:         BOOST_PROTO_CALLABLE()
Chris@16: 
Chris@16:         template<typename Sig>
Chris@16:         struct result;
Chris@16: 
Chris@16:         template<typename This, typename First, typename Second>
Chris@16:         struct result<This(First, Second)>
Chris@16:         {
Chris@16:             typedef
Chris@16:                 std::pair<
Chris@16:                     typename remove_const<typename remove_reference<First>::type>::type
Chris@16:                   , typename remove_const<typename remove_reference<Second>::type>::type
Chris@16:                 >
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename First, typename Second>
Chris@16:         std::pair<First, Second> operator()(First const &first, Second const &second) const
Chris@16:         {
Chris@16:             return std::make_pair(first, second);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     /// \brief A PolymorphicFunctionObject type that returns
Chris@16:     /// the first element of a std::pair.
Chris@16:     ///
Chris@16:     /// A PolymorphicFunctionObject type that returns
Chris@16:     /// the first element of a std::pair..
Chris@16:     struct first
Chris@16:     {
Chris@16:         BOOST_PROTO_CALLABLE()
Chris@16: 
Chris@16:         template<typename Sig>
Chris@16:         struct result;
Chris@16: 
Chris@16:         template<typename This, typename Pair>
Chris@16:         struct result<This(Pair)>
Chris@16:         {
Chris@16:             typedef typename Pair::first_type type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename This, typename Pair>
Chris@16:         struct result<This(Pair &)>
Chris@16:         {
Chris@16:             typedef typename Pair::first_type &type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename This, typename Pair>
Chris@16:         struct result<This(Pair const &)>
Chris@16:         {
Chris@16:             typedef typename Pair::first_type const &type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename Pair>
Chris@16:         typename Pair::first_type &operator()(Pair &pair) const
Chris@16:         {
Chris@16:             return pair.first;
Chris@16:         }
Chris@16: 
Chris@16:         template<typename Pair>
Chris@16:         typename Pair::first_type const &operator()(Pair const &pair) const
Chris@16:         {
Chris@16:             return pair.first;
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     /// \brief A PolymorphicFunctionObject type that returns
Chris@16:     /// the second element of a std::pair.
Chris@16:     ///
Chris@16:     /// A PolymorphicFunctionObject type that returns
Chris@16:     /// the second element of a std::pair..
Chris@16:     struct second
Chris@16:     {
Chris@16:         BOOST_PROTO_CALLABLE()
Chris@16: 
Chris@16:         template<typename Sig>
Chris@16:         struct result;
Chris@16: 
Chris@16:         template<typename This, typename Pair>
Chris@16:         struct result<This(Pair)>
Chris@16:         {
Chris@16:             typedef typename Pair::second_type type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename This, typename Pair>
Chris@16:         struct result<This(Pair &)>
Chris@16:         {
Chris@16:             typedef typename Pair::second_type &type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename This, typename Pair>
Chris@16:         struct result<This(Pair const &)>
Chris@16:         {
Chris@16:             typedef typename Pair::second_type const &type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename Pair>
Chris@16:         typename Pair::second_type &operator()(Pair &pair) const
Chris@16:         {
Chris@16:             return pair.second;
Chris@16:         }
Chris@16: 
Chris@16:         template<typename Pair>
Chris@16:         typename Pair::second_type const &operator()(Pair const &pair) const
Chris@16:         {
Chris@16:             return pair.second;
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16: }}}
Chris@16: 
Chris@16: #endif