1 | /*============================================================================= |
2 | Copyright (c) 2003 Sam Nabialek |
3 | Copyright (c) 2001-2010 Joel de Guzman |
4 | |
5 | Distributed under the Boost Software License, Version 1.0. (See accompanying |
6 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
7 | =============================================================================*/ |
8 | /////////////////////////////////////////////////////////////////////////////// |
9 | // |
10 | // The Nabialek trick. |
11 | // |
12 | // [ Sam Nabialek; Somewhere, sometime in 2003... ] spirit1 |
13 | // [ JDG November 17, 2009 ] spirit2 |
14 | // [ JDG January 10, 2010 ] Updated to use rule pointers |
15 | // for efficiency. |
16 | // |
17 | /////////////////////////////////////////////////////////////////////////////// |
18 | |
19 | #include <boost/spirit/include/qi.hpp> |
20 | #include <boost/phoenix/operator.hpp> |
21 | #include <iostream> |
22 | #include <string> |
23 | |
24 | namespace client |
25 | { |
26 | namespace qi = boost::spirit::qi; |
27 | namespace ascii = boost::spirit::ascii; |
28 | |
29 | /////////////////////////////////////////////////////////////////////////////// |
30 | // Our nabialek_trick grammar |
31 | /////////////////////////////////////////////////////////////////////////////// |
32 | template <typename Iterator> |
33 | struct nabialek_trick : qi::grammar< |
34 | Iterator, ascii::space_type, qi::locals<qi::rule<Iterator, ascii::space_type>*> > |
35 | { |
36 | nabialek_trick() : nabialek_trick::base_type(start) |
37 | { |
38 | using ascii::alnum; |
39 | using qi::lexeme; |
40 | using qi::lazy; |
41 | using qi::_a; |
42 | using qi::_1; |
43 | |
44 | id = lexeme[*(ascii::alnum | '_')]; |
45 | one = id; |
46 | two = id >> ',' >> id; |
47 | |
48 | keyword.add |
49 | ("one" , &one) |
50 | ("two" , &two) |
51 | ; |
52 | |
53 | start = *(keyword[_a = _1] >> lazy(*_a)); |
54 | } |
55 | |
56 | qi::rule<Iterator, ascii::space_type> id, one, two; |
57 | qi::rule<Iterator, ascii::space_type, qi::locals<qi::rule<Iterator, ascii::space_type>*> > start; |
58 | qi::symbols<char, qi::rule<Iterator, ascii::space_type>*> keyword; |
59 | }; |
60 | } |
61 | |
62 | /////////////////////////////////////////////////////////////////////////////// |
63 | // Main program |
64 | /////////////////////////////////////////////////////////////////////////////// |
65 | int |
66 | main() |
67 | { |
68 | using boost::spirit::ascii::space; |
69 | typedef std::string::const_iterator iterator_type; |
70 | typedef client::nabialek_trick<iterator_type> nabialek_trick; |
71 | |
72 | nabialek_trick g; // Our grammar |
73 | |
74 | std::string str = "one only\none again\ntwo first,second" ; |
75 | std::string::const_iterator iter = str.begin(); |
76 | std::string::const_iterator end = str.end(); |
77 | bool r = phrase_parse(first&: iter, last: end, expr&: g, skipper: space); |
78 | |
79 | if (r && iter == end) |
80 | { |
81 | std::cout << "-------------------------\n" ; |
82 | std::cout << "Parsing succeeded\n" ; |
83 | std::cout << "-------------------------\n" ; |
84 | } |
85 | else |
86 | { |
87 | std::string rest(iter, end); |
88 | std::cout << "-------------------------\n" ; |
89 | std::cout << "Parsing failed\n" ; |
90 | std::cout << "stopped at: \": " << rest << "\"\n" ; |
91 | std::cout << "-------------------------\n" ; |
92 | } |
93 | |
94 | return 0; |
95 | } |
96 | |
97 | |
98 | |