ceph/src/boost/libs/mpl/include/boost/mpl/aux_/at_impl.hpp

   1
   2 #ifndef BOOST_MPL_AUX_AT_IMPL_HPP_INCLUDED
   3 #define BOOST_MPL_AUX_AT_IMPL_HPP_INCLUDED
   4
   5 // Copyright Aleksey Gurtovoy 2000-2004
   6 //
   7 // Distributed under the Boost Software License, Version 1.0.
   8 // (See accompanying file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10 //
  11 // See http://www.boost.org/libs/mpl for documentation.
  12
  13 // $Id$
  14 // $Date$
  15 // $Revision$
  16
  17 #include <boost/mpl/begin_end.hpp>
  18 #include <boost/mpl/advance.hpp>
  19 #include <boost/mpl/deref.hpp>
  20 #include <boost/mpl/aux_/traits_lambda_spec.hpp>
  21
  22 namespace boost { namespace mpl {
  23
  24 // default implementation; conrete sequences might override it by
  25 // specializing either the 'at_impl' or the primary 'at' template
  26
  27 template< typename Tag >
  28 struct at_impl
  29 {
  30     template< typename Sequence, typename N > struct apply
  31     {
  32         typedef typename advance<
  33               typename begin<Sequence>::type
  34             , N
  35             >::type iter_;
  36
  37         typedef typename deref<iter_>::type type;
  38     };
  39 };
  40
  41 BOOST_MPL_ALGORITM_TRAITS_LAMBDA_SPEC(2, at_impl)
  42
  43 }}
  44
  45 #endif // BOOST_MPL_AUX_AT_IMPL_HPP_INCLUDED