boost/fusion/iterator/prior.hpp
/*=============================================================================
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_PRIOR_05042005_1144)
#define FUSION_PRIOR_05042005_1144
#include <boost/fusion/support/tag_of.hpp>
namespace boost { namespace fusion
{
// Special tags:
struct iterator_facade_tag; // iterator facade tag
struct array_iterator_tag; // boost::array iterator tag
struct mpl_iterator_tag; // mpl sequence iterator tag
struct std_pair_iterator_tag; // std::pair iterator tag
namespace extension
{
template <typename Tag>
struct prior_impl
{
template <typename Iterator>
struct apply {};
};
template <>
struct prior_impl<iterator_facade_tag>
{
template <typename Iterator>
struct apply : Iterator::template prior<Iterator> {};
};
template <>
struct prior_impl<array_iterator_tag>;
template <>
struct prior_impl<mpl_iterator_tag>;
template <>
struct prior_impl<std_pair_iterator_tag>;
}
namespace result_of
{
template <typename Iterator>
struct prior
: extension::prior_impl<typename detail::tag_of<Iterator>::type>::
template apply<Iterator>
{};
}
template <typename Iterator>
typename result_of::prior<Iterator>::type const
prior(Iterator const& i)
{
return result_of::prior<Iterator>::call(i);
}
}}
#endif
