/*============================================================================= | |
Copyright (c) 2001-2006 Joel de Guzman | |
Copyright (c) 2006 Dan Marsden | |
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_20060124_2006) | |
#define FUSION_NEXT_IMPL_20060124_2006 | |
#include <boost/fusion/view/zip_view/zip_view_iterator_fwd.hpp> | |
#include <boost/fusion/iterator/next.hpp> | |
#include <boost/fusion/algorithm/transformation/transform.hpp> | |
#include <boost/fusion/support/unused.hpp> | |
#include <boost/mpl/eval_if.hpp> | |
#include <boost/mpl/identity.hpp> | |
#include <boost/type_traits/is_same.hpp> | |
#include <boost/type_traits/remove_reference.hpp> | |
#include <boost/type_traits/remove_const.hpp> | |
namespace boost { namespace fusion { | |
struct zip_view_iterator_tag; | |
namespace detail | |
{ | |
struct poly_next | |
{ | |
template<typename Sig> | |
struct result; | |
template<typename It> | |
struct result<poly_next(It)> | |
{ | |
typedef typename remove_const< | |
typename remove_reference<It>::type>::type it; | |
typedef typename mpl::eval_if<is_same<it, unused_type>, | |
mpl::identity<unused_type>, | |
result_of::next<it> >::type type; | |
}; | |
template<typename It> | |
typename result<poly_next(It)>::type | |
operator()(const It& it) const | |
{ | |
return fusion::next(it); | |
} | |
unused_type operator()(unused_type const&) const | |
{ | |
return unused_type(); | |
} | |
}; | |
} | |
namespace extension | |
{ | |
template<typename Tag> | |
struct next_impl; | |
template<> | |
struct next_impl<zip_view_iterator_tag> | |
{ | |
template<typename Iterator> | |
struct apply | |
{ | |
typedef fusion::zip_view_iterator< | |
typename result_of::transform<typename Iterator::iterators, detail::poly_next>::type, | |
typename Iterator::category> type; | |
static type | |
call(Iterator const& it) | |
{ | |
return type( | |
fusion::transform(it.iterators_, detail::poly_next())); | |
} | |
}; | |
}; | |
} | |
}} | |
#endif |