| /*============================================================================= | |
| Copyright (c) 2001-2006 Joel de Guzman | |
| Distributed under the Boost Software License, Version 1.0. (See accompanying | |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
| ==============================================================================*/ | |
| #if !defined(FUSION_VALUE_AT_IMPL_07172005_0952) | |
| #define FUSION_VALUE_AT_IMPL_07172005_0952 | |
| #include <boost/fusion/support/detail/access.hpp> | |
| #include <boost/type_traits/is_const.hpp> | |
| #include <boost/mpl/eval_if.hpp> | |
| #include <boost/mpl/bool.hpp> | |
| namespace boost { namespace fusion | |
| { | |
| struct cons_tag; | |
| namespace extension | |
| { | |
| template <typename Tag> | |
| struct value_at_impl; | |
| template <> | |
| struct value_at_impl<cons_tag> | |
| { | |
| template <typename Sequence, typename N> | |
| struct apply | |
| { | |
| typedef typename | |
| mpl::eval_if< | |
| mpl::bool_<N::value == 0> | |
| , mpl::identity<typename Sequence::car_type> | |
| , apply<typename Sequence::cdr_type, mpl::int_<N::value-1> > | |
| >::type | |
| type; | |
| }; | |
| }; | |
| } | |
| }} | |
| #endif |