| 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 |
| 46 |