| /*============================================================================= |
| 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 |
| |
| |