source: NonGTP/Boost/boost/spirit/utility/functor_parser.hpp @ 857

Revision 857, 2.4 KB checked in by igarcia, 19 years ago (diff)
Line 
1/*=============================================================================
2    Copyright (c) 2002-2003 Joel de Guzman
3    Copyright (c) 2002-2003 Juan Carlos Arevalo-Baeza
4    http://spirit.sourceforge.net/
5
6    Use, modification and distribution is subject to the Boost Software
7    License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
8    http://www.boost.org/LICENSE_1_0.txt)
9=============================================================================*/
10#ifndef BOOST_SPIRIT_FUNCTOR_PARSER_HPP
11#define BOOST_SPIRIT_FUNCTOR_PARSER_HPP
12
13///////////////////////////////////////////////////////////////////////////////
14#include <boost/spirit/core/parser.hpp>
15
16///////////////////////////////////////////////////////////////////////////////
17namespace boost { namespace spirit {
18
19    ///////////////////////////////////////////////////////////////////////////
20    //
21    //  functor_parser class
22    //
23    //      Once a functor parser has been defined, you can build a real
24    //      parser from it by passing it to this class as the template
25    //      parameter.
26    //
27    ///////////////////////////////////////////////////////////////////////////
28    template < class FunctorT >
29    struct functor_parser : public parser<functor_parser<FunctorT> >
30    {
31        FunctorT functor;
32
33        functor_parser(): functor() {}
34        functor_parser(FunctorT const& functor_): functor(functor_) {}
35
36        typedef typename FunctorT::result_t functor_result_t;
37        typedef functor_parser<FunctorT> self_t;
38
39        template <typename ScannerT>
40        struct result
41        {
42            typedef typename match_result<ScannerT, functor_result_t>::type
43            type;
44        };
45
46        template <typename ScannerT>
47        typename parser_result<self_t, ScannerT>::type
48        parse(ScannerT const& scan) const
49        {
50            typedef typename parser_result<self_t, ScannerT>::type result_t;
51            typedef typename ScannerT::value_t      value_t;
52            typedef typename ScannerT::iterator_t   iterator_t;
53
54            iterator_t const s(scan.first);
55            functor_result_t result;
56            std::ptrdiff_t len = functor(scan, result);
57
58            if (len < 0)
59                return scan.no_match();
60            else
61                return scan.create_match(std::size_t(len), result, s, scan.first);
62        }
63    };
64
65}} // namespace boost::spirit
66
67#endif
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