Chris@16: /*=============================================================================
Chris@16:     Copyright (c) 2003 Joel de Guzman
Chris@16:     Copyright (c) 2003 Vaclav Vesely
Chris@16:     http://spirit.sourceforge.net/
Chris@16: 
Chris@16:   Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16:   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: =============================================================================*/
Chris@16: #ifndef BOOST_SPIRIT_LAZY_HPP
Chris@16: #define BOOST_SPIRIT_LAZY_HPP
Chris@16: 
Chris@16: ////////////////////////////////////////////////////////////////////////////////
Chris@16: #include <boost/spirit/home/classic/namespace.hpp>
Chris@16: #include <boost/spirit/home/classic/core/parser.hpp>
Chris@16: #include <boost/spirit/home/classic/phoenix/actor.hpp>
Chris@16: 
Chris@16: ////////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: namespace boost { namespace spirit {
Chris@16: 
Chris@16: BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
Chris@16: 
Chris@16:     ////////////////////////////////////////////////////////////////////////////
Chris@16:     //
Chris@16:     // lazy_parser, holds phoenix actor which returns a spirit parser.
Chris@16:     //
Chris@16:     ////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16:     template<class ActorT>
Chris@16:     struct lazy_parser : parser<lazy_parser<ActorT> >
Chris@16:     {
Chris@16:         typedef lazy_parser<ActorT> self_t;
Chris@16:         typedef typename ::phoenix::actor_result<
Chris@16:             ActorT, ::phoenix::tuple<> >::plain_type actor_result_t;
Chris@16: 
Chris@16:         template<typename ScannerT>
Chris@16:         struct result
Chris@16:         {
Chris@16:             typedef typename
Chris@16:                 parser_result<actor_result_t, ScannerT>::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         lazy_parser(ActorT const& actor_)
Chris@16:         : actor(actor_) {}
Chris@16: 
Chris@16:         template<typename ScannerT>
Chris@16:         typename parser_result<self_t, ScannerT>::type
Chris@16:         parse(ScannerT const& scan) const
Chris@16:         { return actor().parse(scan); }
Chris@16: 
Chris@16:         ActorT actor;
Chris@16:     };
Chris@16: 
Chris@16:     //////////////////////////////
Chris@16:     // lazy_p, returns lazy_parser
Chris@16:     // Usage: lazy_p(actor)
Chris@16:     template<class ActorT>
Chris@16:     lazy_parser<ActorT> lazy_p(ActorT const& actor)
Chris@16:     { return lazy_parser<ActorT>(actor); }
Chris@16: 
Chris@16: BOOST_SPIRIT_CLASSIC_NAMESPACE_END
Chris@16: 
Chris@16: }} // namespace BOOST_SPIRIT_CLASSIC_NS
Chris@16: 
Chris@16: #endif // BOOST_SPIRIT_LAZY_HPP