text: /*=============================================================================
      Copyright (c) 2001-2013 Joel de Guzman
  
      Distributed under the Boost Software License, Version 1.0. (See accompanying
      file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  ==============================================================================*/
  #if !defined(BOOST_FUSION_MAP_DETAIL_VALUE_AT_IMPL_02042013_0821)
  #define BOOST_FUSION_MAP_DETAIL_VALUE_AT_IMPL_02042013_0821
  
  #include <boost/fusion/support/config.hpp>
  #include <boost/mpl/at.hpp>
  #include <boost/utility/declval.hpp>
  
  namespace boost {
  namespace fusion {
  struct map_tag;
  
  namespace extension {
  template <typename Tag> struct value_at_impl;
  
  template <> struct value_at_impl<map_tag> {
    template <typename Sequence, typename N> struct apply {
      typedef mpl::int_<N::value> index;
      typedef decltype(boost::declval<Sequence>().get_val(index())) type;
    };
  };
  } // namespace extension
  } // namespace fusion
  } // namespace boost
  
  #endif
  