mpl/detail/at_impl.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003     Copyright (c) 2005-2006 Dan Marsden
0004
0005     Distributed under the Boost Software License, Version 1.0. (See accompanying
0006     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0007 ==============================================================================*/
0008 #if !defined(BOOST_FUSION_AT_IMPL_31122005_1642)
0009 #define BOOST_FUSION_AT_IMPL_31122005_1642
0010
0011 #include <boost/fusion/support/config.hpp>
0012 #include <boost/mpl/at.hpp>
0013
0014 namespace boost { namespace fusion
0015 {
0016     struct mpl_sequence_tag;
0017
0018     namespace extension
0019     {
0020         template<typename Tag>
0021         struct at_impl;
0022
0023         template <>
0024         struct at_impl<mpl_sequence_tag>
0025         {
0026             template <typename Sequence, typename N>
0027             struct apply
0028             {
0029                 typedef typename mpl::at<Sequence, N>::type type;
0030
0031                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0032                 static type
0033                 call(Sequence)
0034                 {
0035                     return type();
0036                 }
0037             };
0038         };
0039     }
0040 }}
0041
0042 #endif