nview/detail/value_at_impl.hpp

0001 /*=============================================================================
0002     Copyright (c) 2009 Hartmut Kaiser
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
0008 #if !defined(BOOST_FUSION_NVIEW_VALUE_AT_IMPL_SEP_24_2009_0234PM)
0009 #define BOOST_FUSION_NVIEW_VALUE_AT_IMPL_SEP_24_2009_0234PM
0010
0011 #include <boost/fusion/support/config.hpp>
0012 #include <boost/fusion/sequence/intrinsic/value_at.hpp>
0013
0014 namespace boost { namespace fusion
0015 {
0016     struct nview_tag;
0017
0018     namespace extension
0019     {
0020         template<typename Tag>
0021         struct value_at_impl;
0022
0023         template<>
0024         struct value_at_impl<nview_tag>
0025         {
0026             template<typename Sequence, typename N>
0027             struct apply
0028             {
0029                 typedef typename Sequence::sequence_type sequence_type;
0030                 typedef typename Sequence::index_type index_type;
0031
0032                 typedef typename result_of::at<index_type, N>::type index;
0033                 typedef typename result_of::at<sequence_type, index>::type type;
0034             };
0035         };
0036     }
0037
0038 }}
0039
0040 #endif