identity.hpp 951 B

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  1. #ifndef BOOST_MPL_IDENTITY_HPP_INCLUDED
  2. #define BOOST_MPL_IDENTITY_HPP_INCLUDED
  3. // Copyright Aleksey Gurtovoy 2000-2004
  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/aux_/na_spec.hpp>
  14. #include <boost/mpl/aux_/lambda_support.hpp>
  15. namespace boost { namespace mpl {
  16. template<
  17. typename BOOST_MPL_AUX_NA_PARAM(T)
  18. >
  19. struct identity
  20. {
  21. typedef T type;
  22. BOOST_MPL_AUX_LAMBDA_SUPPORT(1, identity, (T))
  23. };
  24. template<
  25. typename BOOST_MPL_AUX_NA_PARAM(T)
  26. >
  27. struct make_identity
  28. {
  29. typedef identity<T> type;
  30. BOOST_MPL_AUX_LAMBDA_SUPPORT(1, make_identity, (T))
  31. };
  32. BOOST_MPL_AUX_NA_SPEC_NO_ETI(1, identity)
  33. BOOST_MPL_AUX_NA_SPEC_NO_ETI(1, make_identity)
  34. }}
  35. #endif // BOOST_MPL_IDENTITY_HPP_INCLUDED