value_at_impl.hpp 1.0 KB

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  1. /*=============================================================================
  2. Copyright (c) 2001-2011 Joel de Guzman
  3. Copyright (c) 2011 Brandon Kohn
  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(BOOST_FUSION_MAP_DETAIL_VALUE_AT_IMPL_HPP)
  8. #define BOOST_FUSION_MAP_DETAIL_VALUE_AT_IMPL_HPP
  9. #include <boost/fusion/support/config.hpp>
  10. #include <boost/mpl/at.hpp>
  11. namespace boost { namespace fusion
  12. {
  13. struct map_tag;
  14. namespace extension
  15. {
  16. template <typename Tag>
  17. struct value_at_impl;
  18. template <>
  19. struct value_at_impl<map_tag>
  20. {
  21. template <typename Sequence, typename N>
  22. struct apply
  23. {
  24. typedef typename mpl::at<typename Sequence::storage_type::types, N>::type type;
  25. };
  26. };
  27. }
  28. }}
  29. #endif //BOOST_FUSION_MAP_DETAIL_VALUE_AT_IMPL_HPP