boost/fusion/container/vector/detail/at_impl.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2011 Joel de Guzman
   3
   4     Distributed under the Boost Software License, Version 1.0. (See accompanying
   5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 ==============================================================================*/
   7 #if !defined(FUSION_AT_IMPL_05042005_0741)
   8 #define FUSION_AT_IMPL_05042005_0741
   9
  10 #include <boost/fusion/support/config.hpp>
  11 #include <boost/fusion/support/detail/access.hpp>
  12 #include <boost/type_traits/is_const.hpp>
  13 #include <boost/mpl/at.hpp>
  14 #include <boost/mpl/int.hpp>
  15
  16 namespace boost { namespace fusion
  17 {
  18     struct vector_tag;
  19
  20     namespace extension
  21     {
  22         template <typename Tag>
  23         struct at_impl;
  24
  25         template <>
  26         struct at_impl<vector_tag>
  27         {
  28             template <typename Sequence, typename N>
  29             struct apply
  30             {
  31                 typedef typename mpl::at<typename Sequence::types, N>::type element;
  32                 typedef typename detail::ref_result<element>::type type;
  33
  34                 BOOST_FUSION_GPU_ENABLED
  35                 static type
  36                 call(Sequence& v)
  37                 {
  38                     BOOST_STATIC_ASSERT((N::value < Sequence::size::value));
  39                     return v.at_impl(N());
  40                 }
  41             };
  42
  43             template <typename Sequence, typename N>
  44             struct apply <Sequence const, N>
  45             {
  46                 typedef typename mpl::at<typename Sequence::types, N>::type element;
  47                 typedef typename detail::cref_result<element>::type type;
  48
  49                 BOOST_FUSION_GPU_ENABLED
  50                 static type
  51                 call(Sequence const& v)
  52                 {
  53                     BOOST_STATIC_ASSERT((N::value < Sequence::size::value));
  54                     return v.at_impl(N());
  55                 }
  56             };
  57         };
  58     }
  59 }}
  60
  61 #endif