boost/fusion/view/iterator_range/detail/at_impl.hpp

   1 /*=============================================================================
   2     Copyright (c) 2007 Tobias Schwinger
   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_ITERATOR_RANGE_AT_IMPL_HPP_INCLUDED)
   9 #define BOOST_FUSION_ITERATOR_RANGE_AT_IMPL_HPP_INCLUDED
  10
  11 #include <boost/fusion/iterator/advance.hpp>
  12 #include <boost/fusion/iterator/deref.hpp>
  13
  14 namespace boost { namespace fusion
  15 {
  16     struct iterator_range_tag;
  17
  18     namespace extension
  19     {
  20         template <typename Tag>
  21         struct at_impl;
  22
  23         template <>
  24         struct at_impl<iterator_range_tag>
  25         {
  26             template <typename Seq, typename N>
  27             struct apply
  28             {
  29                 typedef typename Seq::begin_type begin_type;
  30                 typedef typename result_of::advance<begin_type,N>::type pos;
  31                 typedef typename result_of::deref<pos>::type type;
  32
  33                 static type
  34                 call(Seq& s)
  35                 {
  36                     return * fusion::advance<N>(s.first);
  37                 }
  38             };
  39         };
  40     }
  41 }}
  42
  43 #endif
  44