| /*============================================================================= |
| Copyright (c) 2001-2006 Joel de Guzman |
| |
| 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) |
| ==============================================================================*/ |
| #if !defined(BOOST_FUSION_AT_IMPL_09262006_1920) |
| #define BOOST_FUSION_AT_IMPL_09262006_1920 |
| |
| #include <boost/tuple/tuple.hpp> |
| #include <boost/mpl/if.hpp> |
| |
| namespace boost { namespace fusion |
| { |
| struct boost_tuple_tag; |
| |
| namespace extension |
| { |
| template<typename T> |
| struct at_impl; |
| |
| template <> |
| struct at_impl<boost_tuple_tag> |
| { |
| template <typename Sequence, typename N> |
| struct apply |
| { |
| typedef typename |
| tuples::element<N::value, Sequence>::type |
| element; |
| |
| typedef typename |
| mpl::if_< |
| is_const<Sequence> |
| , typename tuples::access_traits<element>::const_type |
| , typename tuples::access_traits<element>::non_const_type |
| >::type |
| type; |
| |
| static type |
| call(Sequence& seq) |
| { |
| return tuples::get<N::value>(seq); |
| } |
| }; |
| }; |
| } |
| }} |
| |
| #endif |