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3257aa99 DM |
1 | #\r |
2 | # Secret Labs' Regular Expression Engine\r | |
3 | #\r | |
4 | # convert re-style regular expression to sre pattern\r | |
5 | #\r | |
6 | # Copyright (c) 1998-2001 by Secret Labs AB. All rights reserved.\r | |
7 | #\r | |
8 | # See the sre.py file for information on usage and redistribution.\r | |
9 | #\r | |
10 | \r | |
11 | """Internal support module for sre"""\r | |
12 | \r | |
13 | # XXX: show string offset and offending character for all errors\r | |
14 | \r | |
15 | import sys\r | |
16 | \r | |
17 | from sre_constants import *\r | |
18 | \r | |
19 | SPECIAL_CHARS = ".\\[{()*+?^$|"\r | |
20 | REPEAT_CHARS = "*+?{"\r | |
21 | \r | |
22 | DIGITS = set("0123456789")\r | |
23 | \r | |
24 | OCTDIGITS = set("01234567")\r | |
25 | HEXDIGITS = set("0123456789abcdefABCDEF")\r | |
26 | \r | |
27 | WHITESPACE = set(" \t\n\r\v\f")\r | |
28 | \r | |
29 | ESCAPES = {\r | |
30 | r"\a": (LITERAL, ord("\a")),\r | |
31 | r"\b": (LITERAL, ord("\b")),\r | |
32 | r"\f": (LITERAL, ord("\f")),\r | |
33 | r"\n": (LITERAL, ord("\n")),\r | |
34 | r"\r": (LITERAL, ord("\r")),\r | |
35 | r"\t": (LITERAL, ord("\t")),\r | |
36 | r"\v": (LITERAL, ord("\v")),\r | |
37 | r"\\": (LITERAL, ord("\\"))\r | |
38 | }\r | |
39 | \r | |
40 | CATEGORIES = {\r | |
41 | r"\A": (AT, AT_BEGINNING_STRING), # start of string\r | |
42 | r"\b": (AT, AT_BOUNDARY),\r | |
43 | r"\B": (AT, AT_NON_BOUNDARY),\r | |
44 | r"\d": (IN, [(CATEGORY, CATEGORY_DIGIT)]),\r | |
45 | r"\D": (IN, [(CATEGORY, CATEGORY_NOT_DIGIT)]),\r | |
46 | r"\s": (IN, [(CATEGORY, CATEGORY_SPACE)]),\r | |
47 | r"\S": (IN, [(CATEGORY, CATEGORY_NOT_SPACE)]),\r | |
48 | r"\w": (IN, [(CATEGORY, CATEGORY_WORD)]),\r | |
49 | r"\W": (IN, [(CATEGORY, CATEGORY_NOT_WORD)]),\r | |
50 | r"\Z": (AT, AT_END_STRING), # end of string\r | |
51 | }\r | |
52 | \r | |
53 | FLAGS = {\r | |
54 | # standard flags\r | |
55 | "i": SRE_FLAG_IGNORECASE,\r | |
56 | "L": SRE_FLAG_LOCALE,\r | |
57 | "m": SRE_FLAG_MULTILINE,\r | |
58 | "s": SRE_FLAG_DOTALL,\r | |
59 | "x": SRE_FLAG_VERBOSE,\r | |
60 | # extensions\r | |
61 | "t": SRE_FLAG_TEMPLATE,\r | |
62 | "u": SRE_FLAG_UNICODE,\r | |
63 | }\r | |
64 | \r | |
65 | class Pattern:\r | |
66 | # master pattern object. keeps track of global attributes\r | |
67 | def __init__(self):\r | |
68 | self.flags = 0\r | |
69 | self.open = []\r | |
70 | self.groups = 1\r | |
71 | self.groupdict = {}\r | |
72 | self.lookbehind = 0\r | |
73 | \r | |
74 | def opengroup(self, name=None):\r | |
75 | gid = self.groups\r | |
76 | self.groups = gid + 1\r | |
77 | if name is not None:\r | |
78 | ogid = self.groupdict.get(name, None)\r | |
79 | if ogid is not None:\r | |
80 | raise error, ("redefinition of group name %s as group %d; "\r | |
81 | "was group %d" % (repr(name), gid, ogid))\r | |
82 | self.groupdict[name] = gid\r | |
83 | self.open.append(gid)\r | |
84 | return gid\r | |
85 | def closegroup(self, gid):\r | |
86 | self.open.remove(gid)\r | |
87 | def checkgroup(self, gid):\r | |
88 | return gid < self.groups and gid not in self.open\r | |
89 | \r | |
90 | class SubPattern:\r | |
91 | # a subpattern, in intermediate form\r | |
92 | def __init__(self, pattern, data=None):\r | |
93 | self.pattern = pattern\r | |
94 | if data is None:\r | |
95 | data = []\r | |
96 | self.data = data\r | |
97 | self.width = None\r | |
98 | def dump(self, level=0):\r | |
99 | seqtypes = (tuple, list)\r | |
100 | for op, av in self.data:\r | |
101 | print level*" " + op,\r | |
102 | if op == IN:\r | |
103 | # member sublanguage\r | |
104 | print\r | |
105 | for op, a in av:\r | |
106 | print (level+1)*" " + op, a\r | |
107 | elif op == BRANCH:\r | |
108 | print\r | |
109 | for i, a in enumerate(av[1]):\r | |
110 | if i:\r | |
111 | print level*" " + "or"\r | |
112 | a.dump(level+1)\r | |
113 | elif op == GROUPREF_EXISTS:\r | |
114 | condgroup, item_yes, item_no = av\r | |
115 | print condgroup\r | |
116 | item_yes.dump(level+1)\r | |
117 | if item_no:\r | |
118 | print level*" " + "else"\r | |
119 | item_no.dump(level+1)\r | |
120 | elif isinstance(av, seqtypes):\r | |
121 | nl = 0\r | |
122 | for a in av:\r | |
123 | if isinstance(a, SubPattern):\r | |
124 | if not nl:\r | |
125 | print\r | |
126 | a.dump(level+1)\r | |
127 | nl = 1\r | |
128 | else:\r | |
129 | print a,\r | |
130 | nl = 0\r | |
131 | if not nl:\r | |
132 | print\r | |
133 | else:\r | |
134 | print av\r | |
135 | def __repr__(self):\r | |
136 | return repr(self.data)\r | |
137 | def __len__(self):\r | |
138 | return len(self.data)\r | |
139 | def __delitem__(self, index):\r | |
140 | del self.data[index]\r | |
141 | def __getitem__(self, index):\r | |
142 | if isinstance(index, slice):\r | |
143 | return SubPattern(self.pattern, self.data[index])\r | |
144 | return self.data[index]\r | |
145 | def __setitem__(self, index, code):\r | |
146 | self.data[index] = code\r | |
147 | def insert(self, index, code):\r | |
148 | self.data.insert(index, code)\r | |
149 | def append(self, code):\r | |
150 | self.data.append(code)\r | |
151 | def getwidth(self):\r | |
152 | # determine the width (min, max) for this subpattern\r | |
153 | if self.width:\r | |
154 | return self.width\r | |
155 | lo = hi = 0\r | |
156 | UNITCODES = (ANY, RANGE, IN, LITERAL, NOT_LITERAL, CATEGORY)\r | |
157 | REPEATCODES = (MIN_REPEAT, MAX_REPEAT)\r | |
158 | for op, av in self.data:\r | |
159 | if op is BRANCH:\r | |
160 | i = MAXREPEAT - 1\r | |
161 | j = 0\r | |
162 | for av in av[1]:\r | |
163 | l, h = av.getwidth()\r | |
164 | i = min(i, l)\r | |
165 | j = max(j, h)\r | |
166 | lo = lo + i\r | |
167 | hi = hi + j\r | |
168 | elif op is CALL:\r | |
169 | i, j = av.getwidth()\r | |
170 | lo = lo + i\r | |
171 | hi = hi + j\r | |
172 | elif op is SUBPATTERN:\r | |
173 | i, j = av[1].getwidth()\r | |
174 | lo = lo + i\r | |
175 | hi = hi + j\r | |
176 | elif op in REPEATCODES:\r | |
177 | i, j = av[2].getwidth()\r | |
178 | lo = lo + i * av[0]\r | |
179 | hi = hi + j * av[1]\r | |
180 | elif op in UNITCODES:\r | |
181 | lo = lo + 1\r | |
182 | hi = hi + 1\r | |
183 | elif op == SUCCESS:\r | |
184 | break\r | |
185 | self.width = min(lo, MAXREPEAT - 1), min(hi, MAXREPEAT)\r | |
186 | return self.width\r | |
187 | \r | |
188 | class Tokenizer:\r | |
189 | def __init__(self, string):\r | |
190 | self.string = string\r | |
191 | self.index = 0\r | |
192 | self.__next()\r | |
193 | def __next(self):\r | |
194 | if self.index >= len(self.string):\r | |
195 | self.next = None\r | |
196 | return\r | |
197 | char = self.string[self.index]\r | |
198 | if char[0] == "\\":\r | |
199 | try:\r | |
200 | c = self.string[self.index + 1]\r | |
201 | except IndexError:\r | |
202 | raise error, "bogus escape (end of line)"\r | |
203 | char = char + c\r | |
204 | self.index = self.index + len(char)\r | |
205 | self.next = char\r | |
206 | def match(self, char, skip=1):\r | |
207 | if char == self.next:\r | |
208 | if skip:\r | |
209 | self.__next()\r | |
210 | return 1\r | |
211 | return 0\r | |
212 | def get(self):\r | |
213 | this = self.next\r | |
214 | self.__next()\r | |
215 | return this\r | |
216 | def tell(self):\r | |
217 | return self.index, self.next\r | |
218 | def seek(self, index):\r | |
219 | self.index, self.next = index\r | |
220 | \r | |
221 | def isident(char):\r | |
222 | return "a" <= char <= "z" or "A" <= char <= "Z" or char == "_"\r | |
223 | \r | |
224 | def isdigit(char):\r | |
225 | return "0" <= char <= "9"\r | |
226 | \r | |
227 | def isname(name):\r | |
228 | # check that group name is a valid string\r | |
229 | if not isident(name[0]):\r | |
230 | return False\r | |
231 | for char in name[1:]:\r | |
232 | if not isident(char) and not isdigit(char):\r | |
233 | return False\r | |
234 | return True\r | |
235 | \r | |
236 | def _class_escape(source, escape):\r | |
237 | # handle escape code inside character class\r | |
238 | code = ESCAPES.get(escape)\r | |
239 | if code:\r | |
240 | return code\r | |
241 | code = CATEGORIES.get(escape)\r | |
242 | if code and code[0] == IN:\r | |
243 | return code\r | |
244 | try:\r | |
245 | c = escape[1:2]\r | |
246 | if c == "x":\r | |
247 | # hexadecimal escape (exactly two digits)\r | |
248 | while source.next in HEXDIGITS and len(escape) < 4:\r | |
249 | escape = escape + source.get()\r | |
250 | escape = escape[2:]\r | |
251 | if len(escape) != 2:\r | |
252 | raise error, "bogus escape: %s" % repr("\\" + escape)\r | |
253 | return LITERAL, int(escape, 16) & 0xff\r | |
254 | elif c in OCTDIGITS:\r | |
255 | # octal escape (up to three digits)\r | |
256 | while source.next in OCTDIGITS and len(escape) < 4:\r | |
257 | escape = escape + source.get()\r | |
258 | escape = escape[1:]\r | |
259 | return LITERAL, int(escape, 8) & 0xff\r | |
260 | elif c in DIGITS:\r | |
261 | raise error, "bogus escape: %s" % repr(escape)\r | |
262 | if len(escape) == 2:\r | |
263 | return LITERAL, ord(escape[1])\r | |
264 | except ValueError:\r | |
265 | pass\r | |
266 | raise error, "bogus escape: %s" % repr(escape)\r | |
267 | \r | |
268 | def _escape(source, escape, state):\r | |
269 | # handle escape code in expression\r | |
270 | code = CATEGORIES.get(escape)\r | |
271 | if code:\r | |
272 | return code\r | |
273 | code = ESCAPES.get(escape)\r | |
274 | if code:\r | |
275 | return code\r | |
276 | try:\r | |
277 | c = escape[1:2]\r | |
278 | if c == "x":\r | |
279 | # hexadecimal escape\r | |
280 | while source.next in HEXDIGITS and len(escape) < 4:\r | |
281 | escape = escape + source.get()\r | |
282 | if len(escape) != 4:\r | |
283 | raise ValueError\r | |
284 | return LITERAL, int(escape[2:], 16) & 0xff\r | |
285 | elif c == "0":\r | |
286 | # octal escape\r | |
287 | while source.next in OCTDIGITS and len(escape) < 4:\r | |
288 | escape = escape + source.get()\r | |
289 | return LITERAL, int(escape[1:], 8) & 0xff\r | |
290 | elif c in DIGITS:\r | |
291 | # octal escape *or* decimal group reference (sigh)\r | |
292 | if source.next in DIGITS:\r | |
293 | escape = escape + source.get()\r | |
294 | if (escape[1] in OCTDIGITS and escape[2] in OCTDIGITS and\r | |
295 | source.next in OCTDIGITS):\r | |
296 | # got three octal digits; this is an octal escape\r | |
297 | escape = escape + source.get()\r | |
298 | return LITERAL, int(escape[1:], 8) & 0xff\r | |
299 | # not an octal escape, so this is a group reference\r | |
300 | group = int(escape[1:])\r | |
301 | if group < state.groups:\r | |
302 | if not state.checkgroup(group):\r | |
303 | raise error, "cannot refer to open group"\r | |
304 | if state.lookbehind:\r | |
305 | import warnings\r | |
306 | warnings.warn('group references in lookbehind '\r | |
307 | 'assertions are not supported',\r | |
308 | RuntimeWarning)\r | |
309 | return GROUPREF, group\r | |
310 | raise ValueError\r | |
311 | if len(escape) == 2:\r | |
312 | return LITERAL, ord(escape[1])\r | |
313 | except ValueError:\r | |
314 | pass\r | |
315 | raise error, "bogus escape: %s" % repr(escape)\r | |
316 | \r | |
317 | def _parse_sub(source, state, nested=1):\r | |
318 | # parse an alternation: a|b|c\r | |
319 | \r | |
320 | items = []\r | |
321 | itemsappend = items.append\r | |
322 | sourcematch = source.match\r | |
323 | while 1:\r | |
324 | itemsappend(_parse(source, state))\r | |
325 | if sourcematch("|"):\r | |
326 | continue\r | |
327 | if not nested:\r | |
328 | break\r | |
329 | if not source.next or sourcematch(")", 0):\r | |
330 | break\r | |
331 | else:\r | |
332 | raise error, "pattern not properly closed"\r | |
333 | \r | |
334 | if len(items) == 1:\r | |
335 | return items[0]\r | |
336 | \r | |
337 | subpattern = SubPattern(state)\r | |
338 | subpatternappend = subpattern.append\r | |
339 | \r | |
340 | # check if all items share a common prefix\r | |
341 | while 1:\r | |
342 | prefix = None\r | |
343 | for item in items:\r | |
344 | if not item:\r | |
345 | break\r | |
346 | if prefix is None:\r | |
347 | prefix = item[0]\r | |
348 | elif item[0] != prefix:\r | |
349 | break\r | |
350 | else:\r | |
351 | # all subitems start with a common "prefix".\r | |
352 | # move it out of the branch\r | |
353 | for item in items:\r | |
354 | del item[0]\r | |
355 | subpatternappend(prefix)\r | |
356 | continue # check next one\r | |
357 | break\r | |
358 | \r | |
359 | # check if the branch can be replaced by a character set\r | |
360 | for item in items:\r | |
361 | if len(item) != 1 or item[0][0] != LITERAL:\r | |
362 | break\r | |
363 | else:\r | |
364 | # we can store this as a character set instead of a\r | |
365 | # branch (the compiler may optimize this even more)\r | |
366 | set = []\r | |
367 | setappend = set.append\r | |
368 | for item in items:\r | |
369 | setappend(item[0])\r | |
370 | subpatternappend((IN, set))\r | |
371 | return subpattern\r | |
372 | \r | |
373 | subpattern.append((BRANCH, (None, items)))\r | |
374 | return subpattern\r | |
375 | \r | |
376 | def _parse_sub_cond(source, state, condgroup):\r | |
377 | item_yes = _parse(source, state)\r | |
378 | if source.match("|"):\r | |
379 | item_no = _parse(source, state)\r | |
380 | if source.match("|"):\r | |
381 | raise error, "conditional backref with more than two branches"\r | |
382 | else:\r | |
383 | item_no = None\r | |
384 | if source.next and not source.match(")", 0):\r | |
385 | raise error, "pattern not properly closed"\r | |
386 | subpattern = SubPattern(state)\r | |
387 | subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))\r | |
388 | return subpattern\r | |
389 | \r | |
390 | _PATTERNENDERS = set("|)")\r | |
391 | _ASSERTCHARS = set("=!<")\r | |
392 | _LOOKBEHINDASSERTCHARS = set("=!")\r | |
393 | _REPEATCODES = set([MIN_REPEAT, MAX_REPEAT])\r | |
394 | \r | |
395 | def _parse(source, state):\r | |
396 | # parse a simple pattern\r | |
397 | subpattern = SubPattern(state)\r | |
398 | \r | |
399 | # precompute constants into local variables\r | |
400 | subpatternappend = subpattern.append\r | |
401 | sourceget = source.get\r | |
402 | sourcematch = source.match\r | |
403 | _len = len\r | |
404 | PATTERNENDERS = _PATTERNENDERS\r | |
405 | ASSERTCHARS = _ASSERTCHARS\r | |
406 | LOOKBEHINDASSERTCHARS = _LOOKBEHINDASSERTCHARS\r | |
407 | REPEATCODES = _REPEATCODES\r | |
408 | \r | |
409 | while 1:\r | |
410 | \r | |
411 | if source.next in PATTERNENDERS:\r | |
412 | break # end of subpattern\r | |
413 | this = sourceget()\r | |
414 | if this is None:\r | |
415 | break # end of pattern\r | |
416 | \r | |
417 | if state.flags & SRE_FLAG_VERBOSE:\r | |
418 | # skip whitespace and comments\r | |
419 | if this in WHITESPACE:\r | |
420 | continue\r | |
421 | if this == "#":\r | |
422 | while 1:\r | |
423 | this = sourceget()\r | |
424 | if this in (None, "\n"):\r | |
425 | break\r | |
426 | continue\r | |
427 | \r | |
428 | if this and this[0] not in SPECIAL_CHARS:\r | |
429 | subpatternappend((LITERAL, ord(this)))\r | |
430 | \r | |
431 | elif this == "[":\r | |
432 | # character set\r | |
433 | set = []\r | |
434 | setappend = set.append\r | |
435 | ## if sourcematch(":"):\r | |
436 | ## pass # handle character classes\r | |
437 | if sourcematch("^"):\r | |
438 | setappend((NEGATE, None))\r | |
439 | # check remaining characters\r | |
440 | start = set[:]\r | |
441 | while 1:\r | |
442 | this = sourceget()\r | |
443 | if this == "]" and set != start:\r | |
444 | break\r | |
445 | elif this and this[0] == "\\":\r | |
446 | code1 = _class_escape(source, this)\r | |
447 | elif this:\r | |
448 | code1 = LITERAL, ord(this)\r | |
449 | else:\r | |
450 | raise error, "unexpected end of regular expression"\r | |
451 | if sourcematch("-"):\r | |
452 | # potential range\r | |
453 | this = sourceget()\r | |
454 | if this == "]":\r | |
455 | if code1[0] is IN:\r | |
456 | code1 = code1[1][0]\r | |
457 | setappend(code1)\r | |
458 | setappend((LITERAL, ord("-")))\r | |
459 | break\r | |
460 | elif this:\r | |
461 | if this[0] == "\\":\r | |
462 | code2 = _class_escape(source, this)\r | |
463 | else:\r | |
464 | code2 = LITERAL, ord(this)\r | |
465 | if code1[0] != LITERAL or code2[0] != LITERAL:\r | |
466 | raise error, "bad character range"\r | |
467 | lo = code1[1]\r | |
468 | hi = code2[1]\r | |
469 | if hi < lo:\r | |
470 | raise error, "bad character range"\r | |
471 | setappend((RANGE, (lo, hi)))\r | |
472 | else:\r | |
473 | raise error, "unexpected end of regular expression"\r | |
474 | else:\r | |
475 | if code1[0] is IN:\r | |
476 | code1 = code1[1][0]\r | |
477 | setappend(code1)\r | |
478 | \r | |
479 | # XXX: <fl> should move set optimization to compiler!\r | |
480 | if _len(set)==1 and set[0][0] is LITERAL:\r | |
481 | subpatternappend(set[0]) # optimization\r | |
482 | elif _len(set)==2 and set[0][0] is NEGATE and set[1][0] is LITERAL:\r | |
483 | subpatternappend((NOT_LITERAL, set[1][1])) # optimization\r | |
484 | else:\r | |
485 | # XXX: <fl> should add charmap optimization here\r | |
486 | subpatternappend((IN, set))\r | |
487 | \r | |
488 | elif this and this[0] in REPEAT_CHARS:\r | |
489 | # repeat previous item\r | |
490 | if this == "?":\r | |
491 | min, max = 0, 1\r | |
492 | elif this == "*":\r | |
493 | min, max = 0, MAXREPEAT\r | |
494 | \r | |
495 | elif this == "+":\r | |
496 | min, max = 1, MAXREPEAT\r | |
497 | elif this == "{":\r | |
498 | if source.next == "}":\r | |
499 | subpatternappend((LITERAL, ord(this)))\r | |
500 | continue\r | |
501 | here = source.tell()\r | |
502 | min, max = 0, MAXREPEAT\r | |
503 | lo = hi = ""\r | |
504 | while source.next in DIGITS:\r | |
505 | lo = lo + source.get()\r | |
506 | if sourcematch(","):\r | |
507 | while source.next in DIGITS:\r | |
508 | hi = hi + sourceget()\r | |
509 | else:\r | |
510 | hi = lo\r | |
511 | if not sourcematch("}"):\r | |
512 | subpatternappend((LITERAL, ord(this)))\r | |
513 | source.seek(here)\r | |
514 | continue\r | |
515 | if lo:\r | |
516 | min = int(lo)\r | |
517 | if min >= MAXREPEAT:\r | |
518 | raise OverflowError("the repetition number is too large")\r | |
519 | if hi:\r | |
520 | max = int(hi)\r | |
521 | if max >= MAXREPEAT:\r | |
522 | raise OverflowError("the repetition number is too large")\r | |
523 | if max < min:\r | |
524 | raise error("bad repeat interval")\r | |
525 | else:\r | |
526 | raise error, "not supported"\r | |
527 | # figure out which item to repeat\r | |
528 | if subpattern:\r | |
529 | item = subpattern[-1:]\r | |
530 | else:\r | |
531 | item = None\r | |
532 | if not item or (_len(item) == 1 and item[0][0] == AT):\r | |
533 | raise error, "nothing to repeat"\r | |
534 | if item[0][0] in REPEATCODES:\r | |
535 | raise error, "multiple repeat"\r | |
536 | if sourcematch("?"):\r | |
537 | subpattern[-1] = (MIN_REPEAT, (min, max, item))\r | |
538 | else:\r | |
539 | subpattern[-1] = (MAX_REPEAT, (min, max, item))\r | |
540 | \r | |
541 | elif this == ".":\r | |
542 | subpatternappend((ANY, None))\r | |
543 | \r | |
544 | elif this == "(":\r | |
545 | group = 1\r | |
546 | name = None\r | |
547 | condgroup = None\r | |
548 | if sourcematch("?"):\r | |
549 | group = 0\r | |
550 | # options\r | |
551 | if sourcematch("P"):\r | |
552 | # python extensions\r | |
553 | if sourcematch("<"):\r | |
554 | # named group: skip forward to end of name\r | |
555 | name = ""\r | |
556 | while 1:\r | |
557 | char = sourceget()\r | |
558 | if char is None:\r | |
559 | raise error, "unterminated name"\r | |
560 | if char == ">":\r | |
561 | break\r | |
562 | name = name + char\r | |
563 | group = 1\r | |
564 | if not name:\r | |
565 | raise error("missing group name")\r | |
566 | if not isname(name):\r | |
567 | raise error("bad character in group name %r" %\r | |
568 | name)\r | |
569 | elif sourcematch("="):\r | |
570 | # named backreference\r | |
571 | name = ""\r | |
572 | while 1:\r | |
573 | char = sourceget()\r | |
574 | if char is None:\r | |
575 | raise error, "unterminated name"\r | |
576 | if char == ")":\r | |
577 | break\r | |
578 | name = name + char\r | |
579 | if not name:\r | |
580 | raise error("missing group name")\r | |
581 | if not isname(name):\r | |
582 | raise error("bad character in backref group name "\r | |
583 | "%r" % name)\r | |
584 | gid = state.groupdict.get(name)\r | |
585 | if gid is None:\r | |
586 | msg = "unknown group name: {0!r}".format(name)\r | |
587 | raise error(msg)\r | |
588 | if state.lookbehind:\r | |
589 | import warnings\r | |
590 | warnings.warn('group references in lookbehind '\r | |
591 | 'assertions are not supported',\r | |
592 | RuntimeWarning)\r | |
593 | subpatternappend((GROUPREF, gid))\r | |
594 | continue\r | |
595 | else:\r | |
596 | char = sourceget()\r | |
597 | if char is None:\r | |
598 | raise error, "unexpected end of pattern"\r | |
599 | raise error, "unknown specifier: ?P%s" % char\r | |
600 | elif sourcematch(":"):\r | |
601 | # non-capturing group\r | |
602 | group = 2\r | |
603 | elif sourcematch("#"):\r | |
604 | # comment\r | |
605 | while 1:\r | |
606 | if source.next is None or source.next == ")":\r | |
607 | break\r | |
608 | sourceget()\r | |
609 | if not sourcematch(")"):\r | |
610 | raise error, "unbalanced parenthesis"\r | |
611 | continue\r | |
612 | elif source.next in ASSERTCHARS:\r | |
613 | # lookahead assertions\r | |
614 | char = sourceget()\r | |
615 | dir = 1\r | |
616 | if char == "<":\r | |
617 | if source.next not in LOOKBEHINDASSERTCHARS:\r | |
618 | raise error, "syntax error"\r | |
619 | dir = -1 # lookbehind\r | |
620 | char = sourceget()\r | |
621 | state.lookbehind += 1\r | |
622 | p = _parse_sub(source, state)\r | |
623 | if dir < 0:\r | |
624 | state.lookbehind -= 1\r | |
625 | if not sourcematch(")"):\r | |
626 | raise error, "unbalanced parenthesis"\r | |
627 | if char == "=":\r | |
628 | subpatternappend((ASSERT, (dir, p)))\r | |
629 | else:\r | |
630 | subpatternappend((ASSERT_NOT, (dir, p)))\r | |
631 | continue\r | |
632 | elif sourcematch("("):\r | |
633 | # conditional backreference group\r | |
634 | condname = ""\r | |
635 | while 1:\r | |
636 | char = sourceget()\r | |
637 | if char is None:\r | |
638 | raise error, "unterminated name"\r | |
639 | if char == ")":\r | |
640 | break\r | |
641 | condname = condname + char\r | |
642 | group = 2\r | |
643 | if not condname:\r | |
644 | raise error("missing group name")\r | |
645 | if isname(condname):\r | |
646 | condgroup = state.groupdict.get(condname)\r | |
647 | if condgroup is None:\r | |
648 | msg = "unknown group name: {0!r}".format(condname)\r | |
649 | raise error(msg)\r | |
650 | else:\r | |
651 | try:\r | |
652 | condgroup = int(condname)\r | |
653 | except ValueError:\r | |
654 | raise error, "bad character in group name"\r | |
655 | if state.lookbehind:\r | |
656 | import warnings\r | |
657 | warnings.warn('group references in lookbehind '\r | |
658 | 'assertions are not supported',\r | |
659 | RuntimeWarning)\r | |
660 | else:\r | |
661 | # flags\r | |
662 | if not source.next in FLAGS:\r | |
663 | raise error, "unexpected end of pattern"\r | |
664 | while source.next in FLAGS:\r | |
665 | state.flags = state.flags | FLAGS[sourceget()]\r | |
666 | if group:\r | |
667 | # parse group contents\r | |
668 | if group == 2:\r | |
669 | # anonymous group\r | |
670 | group = None\r | |
671 | else:\r | |
672 | group = state.opengroup(name)\r | |
673 | if condgroup:\r | |
674 | p = _parse_sub_cond(source, state, condgroup)\r | |
675 | else:\r | |
676 | p = _parse_sub(source, state)\r | |
677 | if not sourcematch(")"):\r | |
678 | raise error, "unbalanced parenthesis"\r | |
679 | if group is not None:\r | |
680 | state.closegroup(group)\r | |
681 | subpatternappend((SUBPATTERN, (group, p)))\r | |
682 | else:\r | |
683 | while 1:\r | |
684 | char = sourceget()\r | |
685 | if char is None:\r | |
686 | raise error, "unexpected end of pattern"\r | |
687 | if char == ")":\r | |
688 | break\r | |
689 | raise error, "unknown extension"\r | |
690 | \r | |
691 | elif this == "^":\r | |
692 | subpatternappend((AT, AT_BEGINNING))\r | |
693 | \r | |
694 | elif this == "$":\r | |
695 | subpattern.append((AT, AT_END))\r | |
696 | \r | |
697 | elif this and this[0] == "\\":\r | |
698 | code = _escape(source, this, state)\r | |
699 | subpatternappend(code)\r | |
700 | \r | |
701 | else:\r | |
702 | raise error, "parser error"\r | |
703 | \r | |
704 | return subpattern\r | |
705 | \r | |
706 | def parse(str, flags=0, pattern=None):\r | |
707 | # parse 're' pattern into list of (opcode, argument) tuples\r | |
708 | \r | |
709 | source = Tokenizer(str)\r | |
710 | \r | |
711 | if pattern is None:\r | |
712 | pattern = Pattern()\r | |
713 | pattern.flags = flags\r | |
714 | pattern.str = str\r | |
715 | \r | |
716 | p = _parse_sub(source, pattern, 0)\r | |
717 | \r | |
718 | tail = source.get()\r | |
719 | if tail == ")":\r | |
720 | raise error, "unbalanced parenthesis"\r | |
721 | elif tail:\r | |
722 | raise error, "bogus characters at end of regular expression"\r | |
723 | \r | |
724 | if flags & SRE_FLAG_DEBUG:\r | |
725 | p.dump()\r | |
726 | \r | |
727 | if not (flags & SRE_FLAG_VERBOSE) and p.pattern.flags & SRE_FLAG_VERBOSE:\r | |
728 | # the VERBOSE flag was switched on inside the pattern. to be\r | |
729 | # on the safe side, we'll parse the whole thing again...\r | |
730 | return parse(str, p.pattern.flags)\r | |
731 | \r | |
732 | return p\r | |
733 | \r | |
734 | def parse_template(source, pattern):\r | |
735 | # parse 're' replacement string into list of literals and\r | |
736 | # group references\r | |
737 | s = Tokenizer(source)\r | |
738 | sget = s.get\r | |
739 | p = []\r | |
740 | a = p.append\r | |
741 | def literal(literal, p=p, pappend=a):\r | |
742 | if p and p[-1][0] is LITERAL:\r | |
743 | p[-1] = LITERAL, p[-1][1] + literal\r | |
744 | else:\r | |
745 | pappend((LITERAL, literal))\r | |
746 | sep = source[:0]\r | |
747 | if type(sep) is type(""):\r | |
748 | makechar = chr\r | |
749 | else:\r | |
750 | makechar = unichr\r | |
751 | while 1:\r | |
752 | this = sget()\r | |
753 | if this is None:\r | |
754 | break # end of replacement string\r | |
755 | if this and this[0] == "\\":\r | |
756 | # group\r | |
757 | c = this[1:2]\r | |
758 | if c == "g":\r | |
759 | name = ""\r | |
760 | if s.match("<"):\r | |
761 | while 1:\r | |
762 | char = sget()\r | |
763 | if char is None:\r | |
764 | raise error, "unterminated group name"\r | |
765 | if char == ">":\r | |
766 | break\r | |
767 | name = name + char\r | |
768 | if not name:\r | |
769 | raise error, "missing group name"\r | |
770 | try:\r | |
771 | index = int(name)\r | |
772 | if index < 0:\r | |
773 | raise error, "negative group number"\r | |
774 | except ValueError:\r | |
775 | if not isname(name):\r | |
776 | raise error, "bad character in group name"\r | |
777 | try:\r | |
778 | index = pattern.groupindex[name]\r | |
779 | except KeyError:\r | |
780 | msg = "unknown group name: {0!r}".format(name)\r | |
781 | raise IndexError(msg)\r | |
782 | a((MARK, index))\r | |
783 | elif c == "0":\r | |
784 | if s.next in OCTDIGITS:\r | |
785 | this = this + sget()\r | |
786 | if s.next in OCTDIGITS:\r | |
787 | this = this + sget()\r | |
788 | literal(makechar(int(this[1:], 8) & 0xff))\r | |
789 | elif c in DIGITS:\r | |
790 | isoctal = False\r | |
791 | if s.next in DIGITS:\r | |
792 | this = this + sget()\r | |
793 | if (c in OCTDIGITS and this[2] in OCTDIGITS and\r | |
794 | s.next in OCTDIGITS):\r | |
795 | this = this + sget()\r | |
796 | isoctal = True\r | |
797 | literal(makechar(int(this[1:], 8) & 0xff))\r | |
798 | if not isoctal:\r | |
799 | a((MARK, int(this[1:])))\r | |
800 | else:\r | |
801 | try:\r | |
802 | this = makechar(ESCAPES[this][1])\r | |
803 | except KeyError:\r | |
804 | pass\r | |
805 | literal(this)\r | |
806 | else:\r | |
807 | literal(this)\r | |
808 | # convert template to groups and literals lists\r | |
809 | i = 0\r | |
810 | groups = []\r | |
811 | groupsappend = groups.append\r | |
812 | literals = [None] * len(p)\r | |
813 | for c, s in p:\r | |
814 | if c is MARK:\r | |
815 | groupsappend((i, s))\r | |
816 | # literal[i] is already None\r | |
817 | else:\r | |
818 | literals[i] = s\r | |
819 | i = i + 1\r | |
820 | return groups, literals\r | |
821 | \r | |
822 | def expand_template(template, match):\r | |
823 | g = match.group\r | |
824 | sep = match.string[:0]\r | |
825 | groups, literals = template\r | |
826 | literals = literals[:]\r | |
827 | try:\r | |
828 | for index, group in groups:\r | |
829 | literals[index] = s = g(group)\r | |
830 | if s is None:\r | |
831 | raise error, "unmatched group"\r | |
832 | except IndexError:\r | |
833 | raise error, "invalid group reference"\r | |
834 | return sep.join(literals)\r |