boost/spirit/home/classic/utility/flush_multi_pass.hpp
/*=============================================================================
Copyright (c) 2001-2003 Daniel Nuffer
http://spirit.sourceforge.net/
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)
=============================================================================*/
#ifndef BOOST_SPIRIT_FLUSH_MULTI_PASS_HPP
#define BOOST_SPIRIT_FLUSH_MULTI_PASS_HPP
///////////////////////////////////////////////////////////////////////////////
#include <boost/spirit/home/classic/namespace.hpp>
#include <boost/spirit/home/classic/core.hpp>
#include <boost/spirit/home/classic/iterator/multi_pass.hpp>
///////////////////////////////////////////////////////////////////////////////
namespace boost { namespace spirit {
BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
namespace impl {
template <typename T>
void flush_iterator(T &) {}
template <typename T1, typename T2, typename T3, typename T4>
void flush_iterator(BOOST_SPIRIT_CLASSIC_NS::multi_pass<
T1, T2, T3, T4, BOOST_SPIRIT_CLASSIC_NS::multi_pass_policies::std_deque> &i)
{
i.clear_queue();
}
} // namespace impl
///////////////////////////////////////////////////////////////////////////
//
// flush_multi_pass_parser
//
// The flush_multi_pass_parser flushes an underlying
// multi_pass_iterator during the normal parsing process. This may
// be used at certain points during the parsing process, when it is
// clear, that no backtracking is needed anymore and the input
// gathered so far may be discarded.
//
///////////////////////////////////////////////////////////////////////////
class flush_multi_pass_parser
: public parser<flush_multi_pass_parser>
{
public:
typedef flush_multi_pass_parser this_t;
template <typename ScannerT>
typename parser_result<this_t, ScannerT>::type
parse(ScannerT const& scan) const
{
impl::flush_iterator(scan.first);
return scan.empty_match();
}
};
///////////////////////////////////////////////////////////////////////////
//
// predefined flush_multi_pass_p object
//
// This object should may used to flush a multi_pass_iterator along
// the way during the normal parsing process.
//
///////////////////////////////////////////////////////////////////////////
flush_multi_pass_parser const
flush_multi_pass_p = flush_multi_pass_parser();
BOOST_SPIRIT_CLASSIC_NAMESPACE_END
}} // namespace BOOST_SPIRIT_CLASSIC_NS
#endif // BOOST_SPIRIT_FLUSH_MULTI_PASS_HPP
