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1 | /*============================================================================= |
2 | Copyright (c) 1998-2003 Joel de Guzman | |
3 | Copyright (c) 2002 Raghavendra Satish | |
4 | Copyright (c) 2002 Jeff Westfahl | |
5 | http://spirit.sourceforge.net/ | |
6 | ||
7 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
8 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
9 | =============================================================================*/ | |
10 | #if !defined(BOOST_SPIRIT_LOOPS_HPP) | |
11 | #define BOOST_SPIRIT_LOOPS_HPP | |
12 | ||
13 | /////////////////////////////////////////////////////////////////////////////// | |
14 | #include <boost/spirit/home/classic/namespace.hpp> | |
15 | #include <boost/spirit/home/classic/core/parser.hpp> | |
16 | #include <boost/spirit/home/classic/core/composite/composite.hpp> | |
17 | ||
18 | /////////////////////////////////////////////////////////////////////////////// | |
19 | namespace boost { namespace spirit { | |
20 | ||
21 | BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN | |
22 | ||
23 | /////////////////////////////////////////////////////////////////////////// | |
24 | // | |
25 | // fixed_loop class | |
26 | // | |
27 | // This class takes care of the construct: | |
28 | // | |
29 | // repeat_p (exact) [p] | |
30 | // | |
31 | // where 'p' is a parser and 'exact' is the number of times to | |
32 | // repeat. The parser iterates over the input exactly 'exact' times. | |
33 | // The parse function fails if the parser does not match the input | |
34 | // exactly 'exact' times. | |
35 | // | |
36 | // This class is parametizable and can accept constant arguments | |
37 | // (e.g. repeat_p (5) [p]) as well as references to variables (e.g. | |
38 | // repeat_p (ref (n)) [p]). | |
39 | // | |
40 | /////////////////////////////////////////////////////////////////////////// | |
41 | template <typename ParserT, typename ExactT> | |
42 | class fixed_loop | |
43 | : public unary<ParserT, parser <fixed_loop <ParserT, ExactT> > > | |
44 | { | |
45 | public: | |
46 | ||
47 | typedef fixed_loop<ParserT, ExactT> self_t; | |
48 | typedef unary<ParserT, parser<self_t> > base_t; | |
49 | ||
50 | fixed_loop (ParserT const & subject_, ExactT const & exact) | |
51 | : base_t(subject_), m_exact(exact) {} | |
52 | ||
53 | template <typename ScannerT> | |
54 | typename parser_result <self_t, ScannerT>::type | |
55 | parse (ScannerT const & scan) const | |
56 | { | |
57 | typedef typename parser_result<self_t, ScannerT>::type result_t; | |
58 | result_t hit = scan.empty_match(); | |
59 | std::size_t n = m_exact; | |
60 | ||
61 | for (std::size_t i = 0; i < n; ++i) | |
62 | { | |
63 | if (result_t next = this->subject().parse(scan)) | |
64 | { | |
65 | scan.concat_match(hit, next); | |
66 | } | |
67 | else | |
68 | { | |
69 | return scan.no_match(); | |
70 | } | |
71 | } | |
72 | ||
73 | return hit; | |
74 | } | |
75 | ||
76 | template <typename ScannerT> | |
77 | struct result | |
78 | { | |
79 | typedef typename match_result<ScannerT, nil_t>::type type; | |
80 | }; | |
81 | ||
82 | private: | |
83 | ||
84 | ExactT m_exact; | |
85 | }; | |
86 | ||
87 | /////////////////////////////////////////////////////////////////////////////// | |
88 | // | |
89 | // finite_loop class | |
90 | // | |
91 | // This class takes care of the construct: | |
92 | // | |
93 | // repeat_p (min, max) [p] | |
94 | // | |
95 | // where 'p' is a parser, 'min' and 'max' specifies the minimum and | |
96 | // maximum iterations over 'p'. The parser iterates over the input | |
97 | // at least 'min' times and at most 'max' times. The parse function | |
98 | // fails if the parser does not match the input at least 'min' times | |
99 | // and at most 'max' times. | |
100 | // | |
101 | // This class is parametizable and can accept constant arguments | |
102 | // (e.g. repeat_p (5, 10) [p]) as well as references to variables | |
103 | // (e.g. repeat_p (ref (n1), ref (n2)) [p]). | |
104 | // | |
105 | /////////////////////////////////////////////////////////////////////////////// | |
106 | template <typename ParserT, typename MinT, typename MaxT> | |
107 | class finite_loop | |
108 | : public unary<ParserT, parser<finite_loop<ParserT, MinT, MaxT> > > | |
109 | { | |
110 | public: | |
111 | ||
112 | typedef finite_loop <ParserT, MinT, MaxT> self_t; | |
113 | typedef unary<ParserT, parser<self_t> > base_t; | |
114 | ||
115 | finite_loop (ParserT const & subject_, MinT const & min, MaxT const & max) | |
116 | : base_t(subject_), m_min(min), m_max(max) {} | |
117 | ||
118 | template <typename ScannerT> | |
119 | typename parser_result <self_t, ScannerT>::type | |
120 | parse(ScannerT const & scan) const | |
121 | { | |
122 | BOOST_SPIRIT_ASSERT(m_min <= m_max); | |
123 | typedef typename parser_result<self_t, ScannerT>::type result_t; | |
124 | result_t hit = scan.empty_match(); | |
125 | ||
126 | std::size_t n1 = m_min; | |
127 | std::size_t n2 = m_max; | |
128 | ||
129 | for (std::size_t i = 0; i < n2; ++i) | |
130 | { | |
131 | typename ScannerT::iterator_t save = scan.first; | |
132 | result_t next = this->subject().parse(scan); | |
133 | ||
134 | if (!next) | |
135 | { | |
136 | if (i >= n1) | |
137 | { | |
138 | scan.first = save; | |
139 | break; | |
140 | } | |
141 | else | |
142 | { | |
143 | return scan.no_match(); | |
144 | } | |
145 | } | |
146 | ||
147 | scan.concat_match(hit, next); | |
148 | } | |
149 | ||
150 | return hit; | |
151 | } | |
152 | ||
153 | template <typename ScannerT> | |
154 | struct result | |
155 | { | |
156 | typedef typename match_result<ScannerT, nil_t>::type type; | |
157 | }; | |
158 | ||
159 | private: | |
160 | ||
161 | MinT m_min; | |
162 | MaxT m_max; | |
163 | }; | |
164 | ||
165 | /////////////////////////////////////////////////////////////////////////////// | |
166 | // | |
167 | // infinite_loop class | |
168 | // | |
169 | // This class takes care of the construct: | |
170 | // | |
171 | // repeat_p (min, more) [p] | |
172 | // | |
173 | // where 'p' is a parser, 'min' is the minimum iteration over 'p' | |
174 | // and more specifies that the iteration should proceed | |
175 | // indefinitely. The parser iterates over the input at least 'min' | |
176 | // times and continues indefinitely until 'p' fails or all of the | |
177 | // input is parsed. The parse function fails if the parser does not | |
178 | // match the input at least 'min' times. | |
179 | // | |
180 | // This class is parametizable and can accept constant arguments | |
181 | // (e.g. repeat_p (5, more) [p]) as well as references to variables | |
182 | // (e.g. repeat_p (ref (n), more) [p]). | |
183 | // | |
184 | /////////////////////////////////////////////////////////////////////////////// | |
185 | ||
186 | struct more_t {}; | |
187 | more_t const more = more_t (); | |
188 | ||
189 | template <typename ParserT, typename MinT> | |
190 | class infinite_loop | |
191 | : public unary<ParserT, parser<infinite_loop<ParserT, MinT> > > | |
192 | { | |
193 | public: | |
194 | ||
195 | typedef infinite_loop <ParserT, MinT> self_t; | |
196 | typedef unary<ParserT, parser<self_t> > base_t; | |
197 | ||
198 | infinite_loop ( | |
199 | ParserT const& subject_, | |
200 | MinT const& min, | |
201 | more_t const& | |
202 | ) | |
203 | : base_t(subject_), m_min(min) {} | |
204 | ||
205 | template <typename ScannerT> | |
206 | typename parser_result <self_t, ScannerT>::type | |
207 | parse(ScannerT const & scan) const | |
208 | { | |
209 | typedef typename parser_result<self_t, ScannerT>::type result_t; | |
210 | result_t hit = scan.empty_match(); | |
211 | std::size_t n = m_min; | |
212 | ||
213 | for (std::size_t i = 0; ; ++i) | |
214 | { | |
215 | typename ScannerT::iterator_t save = scan.first; | |
216 | result_t next = this->subject().parse(scan); | |
217 | ||
218 | if (!next) | |
219 | { | |
220 | if (i >= n) | |
221 | { | |
222 | scan.first = save; | |
223 | break; | |
224 | } | |
225 | else | |
226 | { | |
227 | return scan.no_match(); | |
228 | } | |
229 | } | |
230 | ||
231 | scan.concat_match(hit, next); | |
232 | } | |
233 | ||
234 | return hit; | |
235 | } | |
236 | ||
237 | template <typename ScannerT> | |
238 | struct result | |
239 | { | |
240 | typedef typename match_result<ScannerT, nil_t>::type type; | |
241 | }; | |
242 | ||
243 | private: | |
244 | ||
245 | MinT m_min; | |
246 | }; | |
247 | ||
248 | template <typename ExactT> | |
249 | struct fixed_loop_gen | |
250 | { | |
251 | fixed_loop_gen (ExactT const & exact) | |
252 | : m_exact (exact) {} | |
253 | ||
254 | template <typename ParserT> | |
255 | fixed_loop <ParserT, ExactT> | |
256 | operator[](parser <ParserT> const & subject_) const | |
257 | { | |
258 | return fixed_loop <ParserT, ExactT> (subject_.derived (), m_exact); | |
259 | } | |
260 | ||
261 | ExactT m_exact; | |
262 | }; | |
263 | ||
264 | namespace impl { | |
265 | ||
266 | template <typename ParserT, typename MinT, typename MaxT> | |
267 | struct loop_traits | |
268 | { | |
269 | typedef typename mpl::if_< | |
270 | boost::is_same<MaxT, more_t>, | |
271 | infinite_loop<ParserT, MinT>, | |
272 | finite_loop<ParserT, MinT, MaxT> | |
273 | >::type type; | |
274 | }; | |
275 | ||
276 | } // namespace impl | |
277 | ||
278 | template <typename MinT, typename MaxT> | |
279 | struct nonfixed_loop_gen | |
280 | { | |
281 | nonfixed_loop_gen (MinT min, MaxT max) | |
282 | : m_min (min), m_max (max) {} | |
283 | ||
284 | template <typename ParserT> | |
285 | typename impl::loop_traits<ParserT, MinT, MaxT>::type | |
286 | operator[](parser <ParserT> const & subject_) const | |
287 | { | |
288 | typedef typename impl::loop_traits<ParserT, MinT, MaxT>::type ret_t; | |
289 | return ret_t( | |
290 | subject_.derived(), | |
291 | m_min, | |
292 | m_max); | |
293 | } | |
294 | ||
295 | MinT m_min; | |
296 | MaxT m_max; | |
297 | }; | |
298 | ||
299 | template <typename ExactT> | |
300 | fixed_loop_gen <ExactT> | |
301 | repeat_p(ExactT const & exact) | |
302 | { | |
303 | return fixed_loop_gen <ExactT> (exact); | |
304 | } | |
305 | ||
306 | template <typename MinT, typename MaxT> | |
307 | nonfixed_loop_gen <MinT, MaxT> | |
308 | repeat_p(MinT const & min, MaxT const & max) | |
309 | { | |
310 | return nonfixed_loop_gen <MinT, MaxT> (min, max); | |
311 | } | |
312 | ||
313 | BOOST_SPIRIT_CLASSIC_NAMESPACE_END | |
314 | ||
315 | }} // namespace BOOST_SPIRIT_CLASSIC_NS | |
316 | ||
317 | #endif // #if !defined(BOOST_SPIRIT_LOOPS_HPP) |