| /*============================================================================= |
| 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_BEGIN_IMPL_07162005_0115) |
| #define FUSION_BEGIN_IMPL_07162005_0115 |
| |
| #include <boost/fusion/iterator/equal_to.hpp> |
| #include <boost/mpl/if.hpp> |
| |
| namespace boost { namespace fusion |
| { |
| struct joint_view_tag; |
| |
| template <typename Category, typename First, typename Last, typename Concat> |
| struct joint_view_iterator; |
| |
| namespace extension |
| { |
| template <typename Tag> |
| struct begin_impl; |
| |
| template <> |
| struct begin_impl<joint_view_tag> |
| { |
| template <typename Sequence> |
| struct apply |
| { |
| typedef typename Sequence::first_type first_type; |
| typedef typename Sequence::last_type last_type; |
| typedef typename Sequence::concat_type concat_type; |
| typedef typename Sequence::category category; |
| typedef result_of::equal_to<first_type, last_type> equal_to; |
| |
| typedef typename |
| mpl::if_< |
| equal_to |
| , concat_type |
| , joint_view_iterator<category, first_type, last_type, concat_type> |
| >::type |
| type; |
| |
| static type |
| call(Sequence& s, mpl::true_) |
| { |
| return s.concat(); |
| } |
| |
| static type |
| call(Sequence& s, mpl::false_) |
| { |
| return type(s.first(), s.concat()); |
| } |
| |
| static type |
| call(Sequence& s) |
| { |
| return call(s, equal_to()); |
| } |
| }; |
| }; |
| } |
| }} |
| |
| #endif |