detail/cpp03/value_at_impl.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003
0004     Distributed under the Boost Software License, Version 1.0. (See accompanying
0005     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 ==============================================================================*/
0007 #if !defined(FUSION_VALUE_AT_IMPL_05052005_0232)
0008 #define FUSION_VALUE_AT_IMPL_05052005_0232
0009
0010 #include <boost/fusion/support/config.hpp>
0011 #include <boost/mpl/at.hpp>
0012
0013 namespace boost { namespace fusion
0014 {
0015     struct vector_tag;
0016
0017     namespace extension
0018     {
0019         template <typename Tag>
0020         struct value_at_impl;
0021
0022         template <>
0023         struct value_at_impl<vector_tag>
0024         {
0025             template <typename Sequence, typename N>
0026             struct apply
0027             {
0028                 typedef typename mpl::at<typename Sequence::types, N>::type type;
0029             };
0030         };
0031     }
0032 }}
0033
0034 #endif