back.hpp 1.3 KB

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  1. /*=============================================================================
  2. Copyright (c) 2001-2011 Joel de Guzman
  3. Distributed under the Boost Software License, Version 1.0. (See accompanying
  4. file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  5. ==============================================================================*/
  6. #if !defined(FUSION_BACK_09162005_0350)
  7. #define FUSION_BACK_09162005_0350
  8. #include <boost/fusion/sequence/intrinsic_fwd.hpp>
  9. #include <boost/fusion/sequence/intrinsic/end.hpp>
  10. #include <boost/fusion/iterator/prior.hpp>
  11. #include <boost/fusion/iterator/deref.hpp>
  12. #include <boost/mpl/bool.hpp>
  13. namespace boost { namespace fusion
  14. {
  15. struct fusion_sequence_tag;
  16. namespace result_of
  17. {
  18. template <typename Sequence>
  19. struct back
  20. : result_of::deref<typename result_of::prior<typename result_of::end<Sequence>::type>::type>
  21. {};
  22. }
  23. template <typename Sequence>
  24. inline typename result_of::back<Sequence>::type
  25. back(Sequence& seq)
  26. {
  27. return *fusion::prior(fusion::end(seq));
  28. }
  29. template <typename Sequence>
  30. inline typename result_of::back<Sequence const>::type
  31. back(Sequence const& seq)
  32. {
  33. return *fusion::prior(fusion::end(seq));
  34. }
  35. }}
  36. #endif