| /*============================================================================= | |
| 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_NEXT_IMPL_07172005_0836) | |
| #define FUSION_NEXT_IMPL_07172005_0836 | |
| #include <boost/fusion/iterator/next.hpp> | |
| #include <boost/fusion/iterator/equal_to.hpp> | |
| #include <boost/mpl/eval_if.hpp> | |
| #include <boost/mpl/identity.hpp> | |
| #include <boost/type_traits/is_const.hpp> | |
| #include <boost/type_traits/add_const.hpp> | |
| namespace boost { namespace fusion | |
| { | |
| struct cons_iterator_tag; | |
| template <typename Cons> | |
| struct cons_iterator; | |
| namespace extension | |
| { | |
| template <typename Tag> | |
| struct next_impl; | |
| template <> | |
| struct next_impl<cons_iterator_tag> | |
| { | |
| template <typename Iterator> | |
| struct apply | |
| { | |
| typedef typename Iterator::cons_type cons_type; | |
| typedef typename cons_type::cdr_type cdr_type; | |
| typedef cons_iterator< | |
| typename mpl::eval_if< | |
| is_const<cons_type> | |
| , add_const<cdr_type> | |
| , mpl::identity<cdr_type> | |
| >::type> | |
| type; | |
| static type | |
| call(Iterator const& i) | |
| { | |
| return type(i.cons.cdr); | |
| } | |
| }; | |
| }; | |
| } | |
| }} | |
| #endif | |