boost/fusion/view/nview/detail/deref_impl.hpp

   1 /*=============================================================================
   2     Copyright (c) 2009 Hartmut Kaiser
   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
   8 #if !defined(BOOST_FUSION_NVIEW_DEREF_IMPL_SEP_24_2009_0818AM)
   9 #define BOOST_FUSION_NVIEW_DEREF_IMPL_SEP_24_2009_0818AM
  10
  11 #include <boost/fusion/iterator/deref.hpp>
  12 #include <boost/fusion/container/vector.hpp>
  13
  14 namespace boost { namespace fusion
  15 {
  16     struct nview_iterator_tag;
  17
  18     namespace extension
  19     {
  20         template<typename Tag>
  21         struct deref_impl;
  22
  23         template<>
  24         struct deref_impl<nview_iterator_tag>
  25         {
  26             template<typename Iterator>
  27             struct apply
  28             {
  29                 typedef typename Iterator::first_type first_type;
  30                 typedef typename Iterator::sequence_type sequence_type;
  31
  32                 typedef typename result_of::deref<first_type>::type index;
  33                 typedef typename result_of::at<
  34                     typename sequence_type::sequence_type, index>::type type;
  35
  36                 static type call(Iterator const& i)
  37                 {
  38                     return at<index>(i.seq.seq);
  39                 }
  40             };
  41         };
  42
  43     }
  44
  45 }}
  46
  47 #endif
  48