core/composite/kleene_star.hpp

0001 /*=============================================================================
0002     Copyright (c) 1998-2003 Joel de Guzman
0003     Copyright (c) 2001 Daniel Nuffer
0004     Copyright (c) 2002 Hartmut Kaiser
0005     http://spirit.sourceforge.net/
0006
0007   Distributed under the Boost Software License, Version 1.0. (See accompanying
0008   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0009 =============================================================================*/
0010 #if !defined(BOOST_SPIRIT_KLEENE_STAR_HPP)
0011 #define BOOST_SPIRIT_KLEENE_STAR_HPP
0012
0013 #include <boost/spirit/home/classic/namespace.hpp>
0014 #include <boost/spirit/home/classic/core/parser.hpp>
0015 #include <boost/spirit/home/classic/core/primitives/primitives.hpp>
0016 #include <boost/spirit/home/classic/core/composite/composite.hpp>
0017 #include <boost/spirit/home/classic/meta/as_parser.hpp>
0018
0019 namespace boost { namespace spirit {
0020
0021 BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
0022
0023     ///////////////////////////////////////////////////////////////////////////
0024     //
0025     //  kleene_star class
0026     //
0027     //      Handles expressions of the form:
0028     //
0029     //          *a
0030     //
0031     //      where a is a parser. The expression returns a composite
0032     //      parser that matches its subject zero (0) or more times.
0033     //
0034     ///////////////////////////////////////////////////////////////////////////
0035     struct kleene_star_parser_gen;
0036
0037 #if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
0038 #pragma warning(push)
0039 #pragma warning(disable:4512) //assignment operator could not be generated
0040 #endif
0041
0042     template <typename S>
0043     struct kleene_star
0044     :   public unary<S, parser<kleene_star<S> > >
0045     {
0046         typedef kleene_star<S>              self_t;
0047         typedef unary_parser_category       parser_category_t;
0048         typedef kleene_star_parser_gen      parser_generator_t;
0049         typedef unary<S, parser<self_t> >   base_t;
0050
0051         kleene_star(S const& a)
0052         : base_t(a) {}
0053
0054         template <typename ScannerT>
0055         typename parser_result<self_t, ScannerT>::type
0056         parse(ScannerT const& scan) const
0057         {
0058             typedef typename parser_result<self_t, ScannerT>::type result_t;
0059             typedef typename ScannerT::iterator_t iterator_t;
0060             result_t hit = scan.empty_match();
0061
0062             for (;;)
0063             {
0064                 iterator_t save = scan.first;
0065                 if (result_t next = this->subject().parse(scan))
0066                 {
0067                     scan.concat_match(hit, next);
0068                 }
0069                 else
0070                 {
0071                     scan.first = save;
0072                     return hit;
0073                 }
0074             }
0075         }
0076     };
0077
0078 #if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
0079 #pragma warning(pop)
0080 #endif
0081
0082     struct kleene_star_parser_gen
0083     {
0084         template <typename S>
0085         struct result
0086         {
0087             typedef kleene_star<S> type;
0088         };
0089
0090         template <typename S>
0091         static kleene_star<S>
0092         generate(parser<S> const& a)
0093         {
0094             return kleene_star<S>(a.derived());
0095         }
0096     };
0097
0098     //////////////////////////////////
0099     template <typename S>
0100     kleene_star<S>
0101     operator*(parser<S> const& a);
0102
0103 BOOST_SPIRIT_CLASSIC_NAMESPACE_END
0104
0105 }} // namespace BOOST_SPIRIT_CLASSIC_NS
0106
0107 #endif
0108
0109 #include <boost/spirit/home/classic/core/composite/impl/kleene_star.ipp>