| /*============================================================================= | |
| Copyright (c) 2005 Joel de Guzman | |
| Copyright (c) 2005 Eric Niebler | |
| 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_DEREF_IMPL_07172005_0831) | |
| #define FUSION_DEREF_IMPL_07172005_0831 | |
| #include <boost/mpl/eval_if.hpp> | |
| #include <boost/type_traits/is_const.hpp> | |
| #include <boost/type_traits/add_const.hpp> | |
| #include <boost/type_traits/add_reference.hpp> | |
| namespace boost { namespace fusion | |
| { | |
| struct cons_iterator_tag; | |
| namespace extension | |
| { | |
| template <typename Tag> | |
| struct deref_impl; | |
| template <> | |
| struct deref_impl<cons_iterator_tag> | |
| { | |
| template <typename Iterator> | |
| struct apply | |
| { | |
| typedef typename Iterator::cons_type cons_type; | |
| typedef typename cons_type::car_type value_type; | |
| typedef typename mpl::eval_if< | |
| is_const<cons_type> | |
| , add_reference<typename add_const<value_type>::type> | |
| , add_reference<value_type> >::type | |
| type; | |
| static type | |
| call(Iterator const& i) | |
| { | |
| return i.cons.car; | |
| } | |
| }; | |
| }; | |
| } | |
| }} | |
| #endif | |