front.hpp 1.2 KB

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  1. #ifndef BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED
  2. #define BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED
  3. // Copyright Aleksey Gurtovoy 2000-2008
  4. //
  5. // Distributed under the Boost Software License, Version 1.0.
  6. // (See accompanying file LICENSE_1_0.txt or copy at
  7. // http://www.boost.org/LICENSE_1_0.txt)
  8. //
  9. // See http://www.boost.org/libs/mpl for documentation.
  10. // $Id$
  11. // $Date$
  12. // $Revision$
  13. #include <boost/mpl/front_fwd.hpp>
  14. #include <boost/mpl/vector/aux_/at.hpp>
  15. #include <boost/mpl/vector/aux_/tag.hpp>
  16. #include <boost/mpl/aux_/nttp_decl.hpp>
  17. #include <boost/mpl/aux_/config/typeof.hpp>
  18. #include <boost/mpl/aux_/config/ctps.hpp>
  19. namespace boost { namespace mpl {
  20. #if defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES)
  21. template<>
  22. struct front_impl< aux::vector_tag >
  23. {
  24. template< typename Vector > struct apply
  25. : v_at<Vector,0>
  26. {
  27. };
  28. };
  29. #else
  30. #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
  31. template< BOOST_MPL_AUX_NTTP_DECL(long, n_) >
  32. struct front_impl< aux::vector_tag<n_> >
  33. {
  34. template< typename Vector > struct apply
  35. {
  36. typedef typename Vector::item0 type;
  37. };
  38. };
  39. #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
  40. #endif // BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES
  41. }}
  42. #endif // BOOST_MPL_VECTOR_AUX_FRONT_HPP_INCLUDED