1 /*=============================================================================
2 Copyright (c) 2002-2003 Joel de Guzman
3 http://spirit.sourceforge.net/
4
5 Use, modification and distribution is subject to the Boost Software
6 License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
7 http://www.boost.org/LICENSE_1_0.txt)
8 =============================================================================*/
9
10 // *** See the section "Look Ma' No Rules" in
11 // *** chapter "Techniques" of the Spirit documentation
12 // *** for information regarding this snippet
13
14 #include <iostream>
15 #include <boost/spirit/include/classic_core.hpp>
16 #include <boost/assert.hpp>
17
18 using namespace BOOST_SPIRIT_CLASSIC_NS;
19
20 namespace boost { namespace spirit
21 {
22 template <typename DerivedT>
23 struct sub_grammar : parser<DerivedT>
24 {
25 typedef sub_grammar self_t;
26 typedef DerivedT const& embed_t;
27
28 template <typename ScannerT>
29 struct result
30 {
31 typedef typename parser_result<
32 typename DerivedT::start_t, ScannerT>::type
33 type;
34 };
35
derivedboost::spirit::sub_grammar36 DerivedT const& derived() const
37 { return *static_cast<DerivedT const*>(this); }
38
39 template <typename ScannerT>
40 typename parser_result<self_t, ScannerT>::type
parseboost::spirit::sub_grammar41 parse(ScannerT const& scan) const
42 {
43 return derived().start.parse(scan);
44 }
45 };
46 }}
47
48 ///////////////////////////////////////////////////////////////////////////////
49 //
50 // Client code
51 //
52 ///////////////////////////////////////////////////////////////////////////////
53 struct skip_grammar : boost::spirit::sub_grammar<skip_grammar>
54 {
55 typedef
56 alternative<alternative<space_parser, sequence<sequence<
57 strlit<const char*>, kleene_star<difference<anychar_parser,
58 chlit<char> > > >, chlit<char> > >, sequence<sequence<
59 strlit<const char*>, kleene_star<difference<anychar_parser,
60 strlit<const char*> > > >, strlit<const char*> > >
61 start_t;
62
skip_grammarskip_grammar63 skip_grammar()
64 : start
65 (
66 space_p
67 | "//" >> *(anychar_p - '\n') >> '\n'
68 | "/*" >> *(anychar_p - "*/") >> "*/"
69 )
70 {}
71
72 start_t start;
73 };
74
75 int
main()76 main()
77 {
78 skip_grammar g;
79
80 bool success = parse(
81 "/*this is a comment*/\n//this is a c++ comment\n\n",
82 *g).full;
83 BOOST_ASSERT(success);
84 std::cout << "SUCCESS!!!\n";
85 return 0;
86 }
87