boost_array/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_27122005_1241)
0009 #define BOOST_FUSION_AT_IMPL_27122005_1241
0010
0011 #include <boost/fusion/support/config.hpp>
0012 #include <boost/type_traits/is_const.hpp>
0013
0014 #include <boost/mpl/if.hpp>
0015
0016 namespace boost { namespace fusion {
0017
0018     struct boost_array_tag;
0019
0020     namespace extension
0021     {
0022         template<typename T>
0023         struct at_impl;
0024
0025         template<>
0026         struct at_impl<boost_array_tag>
0027         {
0028             template<typename Sequence, typename N>
0029             struct apply
0030             {
0031                 typedef typename mpl::if_<
0032                     is_const<Sequence>,
0033                     typename Sequence::const_reference,
0034                     typename Sequence::reference>::type type;
0035
0036                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0037                 static type
0038                 call(Sequence& seq)
0039                 {
0040                     return seq[N::value];
0041                 }
0042             };
0043         };
0044     }
0045 }}
0046
0047 #endif