| /////////////////////////////////////////////////////////////////////////////// |
| /// \file at.hpp |
| /// Proto callables Fusion at |
| // |
| // 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_FUSION_AT_HPP_EAN_11_27_2010 |
| #define BOOST_PROTO_FUNCTIONAL_FUSION_AT_HPP_EAN_11_27_2010 |
| |
| #include <boost/type_traits/add_const.hpp> |
| #include <boost/type_traits/remove_const.hpp> |
| #include <boost/type_traits/remove_reference.hpp> |
| #include <boost/fusion/include/at.hpp> |
| #include <boost/proto/proto_fwd.hpp> |
| |
| namespace boost { namespace proto { namespace functional |
| { |
| /// \brief A PolymorphicFunctionObject type that invokes the |
| /// \c fusion::at() accessor on its argument. |
| /// |
| /// A PolymorphicFunctionObject type that invokes the |
| /// \c fusion::at() accessor on its argument. |
| struct at |
| { |
| BOOST_PROTO_CALLABLE() |
| |
| template<typename Sig> |
| struct result; |
| |
| template<typename This, typename Seq, typename N> |
| struct result<This(Seq, N)> |
| : fusion::result_of::at< |
| typename boost::remove_reference<Seq>::type |
| , typename boost::remove_const<typename boost::remove_reference<N>::type>::type |
| > |
| {}; |
| |
| template<typename Seq, typename N> |
| typename fusion::result_of::at<Seq, N>::type |
| operator ()(Seq &seq, N const & BOOST_PROTO_DISABLE_IF_IS_CONST(Seq)) const |
| { |
| return fusion::at<N>(seq); |
| } |
| |
| template<typename Seq, typename N> |
| typename fusion::result_of::at<Seq const, N>::type |
| operator ()(Seq const &seq, N const &) const |
| { |
| return fusion::at<N>(seq); |
| } |
| }; |
| }}} |
| |
| #endif |