1 # 2 # Secret Labs' Regular Expression Engine 3 # 4 # convert re-style regular expression to sre pattern 5 # 6 # Copyright (c) 1998-2001 by Secret Labs AB. All rights reserved. 7 # 8 # See the sre.py file for information on usage and redistribution. 9 # 10 11 """Internal support module for sre""" 12 13 # XXX: show string offset and offending character for all errors 14 15 import sys 16 17 from sre_constants import * 18 19 SPECIAL_CHARS = ".\\[{()*+?^$|" 20 REPEAT_CHARS = "*+?{" 21 22 DIGITS = set("0123456789") 23 24 OCTDIGITS = set("01234567") 25 HEXDIGITS = set("0123456789abcdefABCDEF") 26 ASCIILETTERS = set("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ") 27 28 WHITESPACE = set(" \t\n\r\v\f") 29 30 ESCAPES = { 31 r"\a": (LITERAL, ord("\a")), 32 r"\b": (LITERAL, ord("\b")), 33 r"\f": (LITERAL, ord("\f")), 34 r"\n": (LITERAL, ord("\n")), 35 r"\r": (LITERAL, ord("\r")), 36 r"\t": (LITERAL, ord("\t")), 37 r"\v": (LITERAL, ord("\v")), 38 r"\\": (LITERAL, ord("\\")) 39 } 40 41 CATEGORIES = { 42 r"\A": (AT, AT_BEGINNING_STRING), # start of string 43 r"\b": (AT, AT_BOUNDARY), 44 r"\B": (AT, AT_NON_BOUNDARY), 45 r"\d": (IN, [(CATEGORY, CATEGORY_DIGIT)]), 46 r"\D": (IN, [(CATEGORY, CATEGORY_NOT_DIGIT)]), 47 r"\s": (IN, [(CATEGORY, CATEGORY_SPACE)]), 48 r"\S": (IN, [(CATEGORY, CATEGORY_NOT_SPACE)]), 49 r"\w": (IN, [(CATEGORY, CATEGORY_WORD)]), 50 r"\W": (IN, [(CATEGORY, CATEGORY_NOT_WORD)]), 51 r"\Z": (AT, AT_END_STRING), # end of string 52 } 53 54 FLAGS = { 55 # standard flags 56 "i": SRE_FLAG_IGNORECASE, 57 "L": SRE_FLAG_LOCALE, 58 "m": SRE_FLAG_MULTILINE, 59 "s": SRE_FLAG_DOTALL, 60 "x": SRE_FLAG_VERBOSE, 61 # extensions 62 "t": SRE_FLAG_TEMPLATE, 63 "u": SRE_FLAG_UNICODE, 64 } 65 66 class Pattern: 67 # master pattern object. keeps track of global attributes 68 def __init__(self): 69 self.flags = 0 70 self.open = [] 71 self.groups = 1 72 self.groupdict = {} 73 self.lookbehind = 0 74 75 def opengroup(self, name=None): 76 gid = self.groups 77 self.groups = gid + 1 78 if name is not None: 79 ogid = self.groupdict.get(name, None) 80 if ogid is not None: 81 raise error, ("redefinition of group name %s as group %d; " 82 "was group %d" % (repr(name), gid, ogid)) 83 self.groupdict[name] = gid 84 self.open.append(gid) 85 return gid 86 def closegroup(self, gid): 87 self.open.remove(gid) 88 def checkgroup(self, gid): 89 return gid < self.groups and gid not in self.open 90 91 class SubPattern: 92 # a subpattern, in intermediate form 93 def __init__(self, pattern, data=None): 94 self.pattern = pattern 95 if data is None: 96 data = [] 97 self.data = data 98 self.width = None 99 def dump(self, level=0): 100 seqtypes = (tuple, list) 101 for op, av in self.data: 102 print level*" " + op, 103 if op == IN: 104 # member sublanguage 105 print 106 for op, a in av: 107 print (level+1)*" " + op, a 108 elif op == BRANCH: 109 print 110 for i, a in enumerate(av[1]): 111 if i: 112 print level*" " + "or" 113 a.dump(level+1) 114 elif op == GROUPREF_EXISTS: 115 condgroup, item_yes, item_no = av 116 print condgroup 117 item_yes.dump(level+1) 118 if item_no: 119 print level*" " + "else" 120 item_no.dump(level+1) 121 elif isinstance(av, seqtypes): 122 nl = 0 123 for a in av: 124 if isinstance(a, SubPattern): 125 if not nl: 126 print 127 a.dump(level+1) 128 nl = 1 129 else: 130 print a, 131 nl = 0 132 if not nl: 133 print 134 else: 135 print av 136 def __repr__(self): 137 return repr(self.data) 138 def __len__(self): 139 return len(self.data) 140 def __delitem__(self, index): 141 del self.data[index] 142 def __getitem__(self, index): 143 if isinstance(index, slice): 144 return SubPattern(self.pattern, self.data[index]) 145 return self.data[index] 146 def __setitem__(self, index, code): 147 self.data[index] = code 148 def insert(self, index, code): 149 self.data.insert(index, code) 150 def append(self, code): 151 self.data.append(code) 152 def getwidth(self): 153 # determine the width (min, max) for this subpattern 154 if self.width: 155 return self.width 156 lo = hi = 0 157 UNITCODES = (ANY, RANGE, IN, LITERAL, NOT_LITERAL, CATEGORY) 158 REPEATCODES = (MIN_REPEAT, MAX_REPEAT) 159 for op, av in self.data: 160 if op is BRANCH: 161 i = MAXREPEAT - 1 162 j = 0 163 for av in av[1]: 164 l, h = av.getwidth() 165 i = min(i, l) 166 j = max(j, h) 167 lo = lo + i 168 hi = hi + j 169 elif op is CALL: 170 i, j = av.getwidth() 171 lo = lo + i 172 hi = hi + j 173 elif op is SUBPATTERN: 174 i, j = av[1].getwidth() 175 lo = lo + i 176 hi = hi + j 177 elif op in REPEATCODES: 178 i, j = av[2].getwidth() 179 lo = lo + i * av[0] 180 hi = hi + j * av[1] 181 elif op in UNITCODES: 182 lo = lo + 1 183 hi = hi + 1 184 elif op == SUCCESS: 185 break 186 self.width = min(lo, MAXREPEAT - 1), min(hi, MAXREPEAT) 187 return self.width 188 189 class Tokenizer: 190 def __init__(self, string): 191 self.string = string 192 self.index = 0 193 self.__next() 194 def __next(self): 195 if self.index >= len(self.string): 196 self.next = None 197 return 198 char = self.string[self.index] 199 if char[0] == "\\": 200 try: 201 c = self.string[self.index + 1] 202 except IndexError: 203 raise error, "bogus escape (end of line)" 204 char = char + c 205 self.index = self.index + len(char) 206 self.next = char 207 def match(self, char, skip=1): 208 if char == self.next: 209 if skip: 210 self.__next() 211 return 1 212 return 0 213 def get(self): 214 this = self.next 215 self.__next() 216 return this 217 def tell(self): 218 return self.index, self.next 219 def seek(self, index): 220 self.index, self.next = index 221 222 def isident(char): 223 return "a" <= char <= "z" or "A" <= char <= "Z" or char == "_" 224 225 def isdigit(char): 226 return "0" <= char <= "9" 227 228 def isname(name): 229 # check that group name is a valid string 230 if not isident(name[0]): 231 return False 232 for char in name[1:]: 233 if not isident(char) and not isdigit(char): 234 return False 235 return True 236 237 def _class_escape(source, escape, nested): 238 # handle escape code inside character class 239 code = ESCAPES.get(escape) 240 if code: 241 return code 242 code = CATEGORIES.get(escape) 243 if code and code[0] == IN: 244 return code 245 try: 246 c = escape[1:2] 247 if c == "x": 248 # hexadecimal escape (exactly two digits) 249 while source.next in HEXDIGITS and len(escape) < 4: 250 escape = escape + source.get() 251 escape = escape[2:] 252 if len(escape) != 2: 253 raise error, "bogus escape: %s" % repr("\\" + escape) 254 return LITERAL, int(escape, 16) & 0xff 255 elif c in OCTDIGITS: 256 # octal escape (up to three digits) 257 while source.next in OCTDIGITS and len(escape) < 4: 258 escape = escape + source.get() 259 escape = escape[1:] 260 return LITERAL, int(escape, 8) & 0xff 261 elif c in DIGITS: 262 raise error, "bogus escape: %s" % repr(escape) 263 if len(escape) == 2: 264 if sys.py3kwarning and c in ASCIILETTERS: 265 import warnings 266 if c in 'Uu': 267 warnings.warn('bad escape %s; Unicode escapes are ' 268 'supported only since Python 3.3' % escape, 269 FutureWarning, stacklevel=nested + 6) 270 else: 271 warnings.warnpy3k('bad escape %s' % escape, 272 DeprecationWarning, stacklevel=nested + 6) 273 return LITERAL, ord(escape[1]) 274 except ValueError: 275 pass 276 raise error, "bogus escape: %s" % repr(escape) 277 278 def _escape(source, escape, state, nested): 279 # handle escape code in expression 280 code = CATEGORIES.get(escape) 281 if code: 282 return code 283 code = ESCAPES.get(escape) 284 if code: 285 return code 286 try: 287 c = escape[1:2] 288 if c == "x": 289 # hexadecimal escape 290 while source.next in HEXDIGITS and len(escape) < 4: 291 escape = escape + source.get() 292 if len(escape) != 4: 293 raise ValueError 294 return LITERAL, int(escape[2:], 16) & 0xff 295 elif c == "0": 296 # octal escape 297 while source.next in OCTDIGITS and len(escape) < 4: 298 escape = escape + source.get() 299 return LITERAL, int(escape[1:], 8) & 0xff 300 elif c in DIGITS: 301 # octal escape *or* decimal group reference (sigh) 302 if source.next in DIGITS: 303 escape = escape + source.get() 304 if (escape[1] in OCTDIGITS and escape[2] in OCTDIGITS and 305 source.next in OCTDIGITS): 306 # got three octal digits; this is an octal escape 307 escape = escape + source.get() 308 return LITERAL, int(escape[1:], 8) & 0xff 309 # not an octal escape, so this is a group reference 310 group = int(escape[1:]) 311 if group < state.groups: 312 if not state.checkgroup(group): 313 raise error, "cannot refer to open group" 314 if state.lookbehind: 315 import warnings 316 warnings.warn('group references in lookbehind ' 317 'assertions are not supported', 318 RuntimeWarning, stacklevel=nested + 6) 319 return GROUPREF, group 320 raise ValueError 321 if len(escape) == 2: 322 if sys.py3kwarning and c in ASCIILETTERS: 323 import warnings 324 if c in 'Uu': 325 warnings.warn('bad escape %s; Unicode escapes are ' 326 'supported only since Python 3.3' % escape, 327 FutureWarning, stacklevel=nested + 6) 328 else: 329 warnings.warnpy3k('bad escape %s' % escape, 330 DeprecationWarning, stacklevel=nested + 6) 331 return LITERAL, ord(escape[1]) 332 except ValueError: 333 pass 334 raise error, "bogus escape: %s" % repr(escape) 335 336 def _parse_sub(source, state, nested): 337 # parse an alternation: a|b|c 338 339 items = [] 340 itemsappend = items.append 341 sourcematch = source.match 342 while 1: 343 itemsappend(_parse(source, state, nested + 1)) 344 if sourcematch("|"): 345 continue 346 if not nested: 347 break 348 if not source.next or sourcematch(")", 0): 349 break 350 else: 351 raise error, "pattern not properly closed" 352 353 if len(items) == 1: 354 return items[0] 355 356 subpattern = SubPattern(state) 357 subpatternappend = subpattern.append 358 359 # check if all items share a common prefix 360 while 1: 361 prefix = None 362 for item in items: 363 if not item: 364 break 365 if prefix is None: 366 prefix = item[0] 367 elif item[0] != prefix: 368 break 369 else: 370 # all subitems start with a common "prefix". 371 # move it out of the branch 372 for item in items: 373 del item[0] 374 subpatternappend(prefix) 375 continue # check next one 376 break 377 378 # check if the branch can be replaced by a character set 379 for item in items: 380 if len(item) != 1 or item[0][0] != LITERAL: 381 break 382 else: 383 # we can store this as a character set instead of a 384 # branch (the compiler may optimize this even more) 385 set = [] 386 setappend = set.append 387 for item in items: 388 setappend(item[0]) 389 subpatternappend((IN, set)) 390 return subpattern 391 392 subpattern.append((BRANCH, (None, items))) 393 return subpattern 394 395 def _parse_sub_cond(source, state, condgroup, nested): 396 item_yes = _parse(source, state, nested + 1) 397 if source.match("|"): 398 item_no = _parse(source, state, nested + 1) 399 if source.match("|"): 400 raise error, "conditional backref with more than two branches" 401 else: 402 item_no = None 403 if source.next and not source.match(")", 0): 404 raise error, "pattern not properly closed" 405 subpattern = SubPattern(state) 406 subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no))) 407 return subpattern 408 409 _PATTERNENDERS = set("|)") 410 _ASSERTCHARS = set("=!<") 411 _LOOKBEHINDASSERTCHARS = set("=!") 412 _REPEATCODES = set([MIN_REPEAT, MAX_REPEAT]) 413 414 def _parse(source, state, nested): 415 # parse a simple pattern 416 subpattern = SubPattern(state) 417 418 # precompute constants into local variables 419 subpatternappend = subpattern.append 420 sourceget = source.get 421 sourcematch = source.match 422 _len = len 423 PATTERNENDERS = _PATTERNENDERS 424 ASSERTCHARS = _ASSERTCHARS 425 LOOKBEHINDASSERTCHARS = _LOOKBEHINDASSERTCHARS 426 REPEATCODES = _REPEATCODES 427 428 while 1: 429 430 if source.next in PATTERNENDERS: 431 break # end of subpattern 432 this = sourceget() 433 if this is None: 434 break # end of pattern 435 436 if state.flags & SRE_FLAG_VERBOSE: 437 # skip whitespace and comments 438 if this in WHITESPACE: 439 continue 440 if this == "#": 441 while 1: 442 this = sourceget() 443 if this in (None, "\n"): 444 break 445 continue 446 447 if this and this[0] not in SPECIAL_CHARS: 448 subpatternappend((LITERAL, ord(this))) 449 450 elif this == "[": 451 # character set 452 set = [] 453 setappend = set.append 454 ## if sourcematch(":"): 455 ## pass # handle character classes 456 if sourcematch("^"): 457 setappend((NEGATE, None)) 458 # check remaining characters 459 start = set[:] 460 while 1: 461 this = sourceget() 462 if this == "]" and set != start: 463 break 464 elif this and this[0] == "\\": 465 code1 = _class_escape(source, this, nested + 1) 466 elif this: 467 code1 = LITERAL, ord(this) 468 else: 469 raise error, "unexpected end of regular expression" 470 if sourcematch("-"): 471 # potential range 472 this = sourceget() 473 if this == "]": 474 if code1[0] is IN: 475 code1 = code1[1][0] 476 setappend(code1) 477 setappend((LITERAL, ord("-"))) 478 break 479 elif this: 480 if this[0] == "\\": 481 code2 = _class_escape(source, this, nested + 1) 482 else: 483 code2 = LITERAL, ord(this) 484 if code1[0] != LITERAL or code2[0] != LITERAL: 485 raise error, "bad character range" 486 lo = code1[1] 487 hi = code2[1] 488 if hi < lo: 489 raise error, "bad character range" 490 setappend((RANGE, (lo, hi))) 491 else: 492 raise error, "unexpected end of regular expression" 493 else: 494 if code1[0] is IN: 495 code1 = code1[1][0] 496 setappend(code1) 497 498 # XXX: <fl> should move set optimization to compiler! 499 if _len(set)==1 and set[0][0] is LITERAL: 500 subpatternappend(set[0]) # optimization 501 elif _len(set)==2 and set[0][0] is NEGATE and set[1][0] is LITERAL: 502 subpatternappend((NOT_LITERAL, set[1][1])) # optimization 503 else: 504 # XXX: <fl> should add charmap optimization here 505 subpatternappend((IN, set)) 506 507 elif this and this[0] in REPEAT_CHARS: 508 # repeat previous item 509 if this == "?": 510 min, max = 0, 1 511 elif this == "*": 512 min, max = 0, MAXREPEAT 513 514 elif this == "+": 515 min, max = 1, MAXREPEAT 516 elif this == "{": 517 if source.next == "}": 518 subpatternappend((LITERAL, ord(this))) 519 continue 520 here = source.tell() 521 min, max = 0, MAXREPEAT 522 lo = hi = "" 523 while source.next in DIGITS: 524 lo = lo + source.get() 525 if sourcematch(","): 526 while source.next in DIGITS: 527 hi = hi + sourceget() 528 else: 529 hi = lo 530 if not sourcematch("}"): 531 subpatternappend((LITERAL, ord(this))) 532 source.seek(here) 533 continue 534 if lo: 535 min = int(lo) 536 if min >= MAXREPEAT: 537 raise OverflowError("the repetition number is too large") 538 if hi: 539 max = int(hi) 540 if max >= MAXREPEAT: 541 raise OverflowError("the repetition number is too large") 542 if max < min: 543 raise error("bad repeat interval") 544 else: 545 raise error, "not supported" 546 # figure out which item to repeat 547 if subpattern: 548 item = subpattern[-1:] 549 else: 550 item = None 551 if not item or (_len(item) == 1 and item[0][0] == AT): 552 raise error, "nothing to repeat" 553 if item[0][0] in REPEATCODES: 554 raise error, "multiple repeat" 555 if sourcematch("?"): 556 subpattern[-1] = (MIN_REPEAT, (min, max, item)) 557 else: 558 subpattern[-1] = (MAX_REPEAT, (min, max, item)) 559 560 elif this == ".": 561 subpatternappend((ANY, None)) 562 563 elif this == "(": 564 group = 1 565 name = None 566 condgroup = None 567 if sourcematch("?"): 568 group = 0 569 # options 570 if sourcematch("P"): 571 # python extensions 572 if sourcematch("<"): 573 # named group: skip forward to end of name 574 name = "" 575 while 1: 576 char = sourceget() 577 if char is None: 578 raise error, "unterminated name" 579 if char == ">": 580 break 581 name = name + char 582 group = 1 583 if not name: 584 raise error("missing group name") 585 if not isname(name): 586 raise error("bad character in group name %r" % 587 name) 588 elif sourcematch("="): 589 # named backreference 590 name = "" 591 while 1: 592 char = sourceget() 593 if char is None: 594 raise error, "unterminated name" 595 if char == ")": 596 break 597 name = name + char 598 if not name: 599 raise error("missing group name") 600 if not isname(name): 601 raise error("bad character in backref group name " 602 "%r" % name) 603 gid = state.groupdict.get(name) 604 if gid is None: 605 msg = "unknown group name: {0!r}".format(name) 606 raise error(msg) 607 if state.lookbehind: 608 import warnings 609 warnings.warn('group references in lookbehind ' 610 'assertions are not supported', 611 RuntimeWarning, stacklevel=nested + 6) 612 subpatternappend((GROUPREF, gid)) 613 continue 614 else: 615 char = sourceget() 616 if char is None: 617 raise error, "unexpected end of pattern" 618 raise error, "unknown specifier: ?P%s" % char 619 elif sourcematch(":"): 620 # non-capturing group 621 group = 2 622 elif sourcematch("#"): 623 # comment 624 while 1: 625 if source.next is None or source.next == ")": 626 break 627 sourceget() 628 if not sourcematch(")"): 629 raise error, "unbalanced parenthesis" 630 continue 631 elif source.next in ASSERTCHARS: 632 # lookahead assertions 633 char = sourceget() 634 dir = 1 635 if char == "<": 636 if source.next not in LOOKBEHINDASSERTCHARS: 637 raise error, "syntax error" 638 dir = -1 # lookbehind 639 char = sourceget() 640 state.lookbehind += 1 641 p = _parse_sub(source, state, nested + 1) 642 if dir < 0: 643 state.lookbehind -= 1 644 if not sourcematch(")"): 645 raise error, "unbalanced parenthesis" 646 if char == "=": 647 subpatternappend((ASSERT, (dir, p))) 648 else: 649 subpatternappend((ASSERT_NOT, (dir, p))) 650 continue 651 elif sourcematch("("): 652 # conditional backreference group 653 condname = "" 654 while 1: 655 char = sourceget() 656 if char is None: 657 raise error, "unterminated name" 658 if char == ")": 659 break 660 condname = condname + char 661 group = 2 662 if not condname: 663 raise error("missing group name") 664 if isname(condname): 665 condgroup = state.groupdict.get(condname) 666 if condgroup is None: 667 msg = "unknown group name: {0!r}".format(condname) 668 raise error(msg) 669 else: 670 try: 671 condgroup = int(condname) 672 except ValueError: 673 raise error, "bad character in group name" 674 if state.lookbehind: 675 import warnings 676 warnings.warn('group references in lookbehind ' 677 'assertions are not supported', 678 RuntimeWarning, stacklevel=nested + 6) 679 else: 680 # flags 681 if not source.next in FLAGS: 682 raise error, "unexpected end of pattern" 683 while source.next in FLAGS: 684 state.flags = state.flags | FLAGS[sourceget()] 685 if group: 686 # parse group contents 687 if group == 2: 688 # anonymous group 689 group = None 690 else: 691 group = state.opengroup(name) 692 if condgroup: 693 p = _parse_sub_cond(source, state, condgroup, nested + 1) 694 else: 695 p = _parse_sub(source, state, nested + 1) 696 if not sourcematch(")"): 697 raise error, "unbalanced parenthesis" 698 if group is not None: 699 state.closegroup(group) 700 subpatternappend((SUBPATTERN, (group, p))) 701 else: 702 while 1: 703 char = sourceget() 704 if char is None: 705 raise error, "unexpected end of pattern" 706 if char == ")": 707 break 708 raise error, "unknown extension" 709 710 elif this == "^": 711 subpatternappend((AT, AT_BEGINNING)) 712 713 elif this == "$": 714 subpattern.append((AT, AT_END)) 715 716 elif this and this[0] == "\\": 717 code = _escape(source, this, state, nested + 1) 718 subpatternappend(code) 719 720 else: 721 raise error, "parser error" 722 723 return subpattern 724 725 def parse(str, flags=0, pattern=None): 726 # parse 're' pattern into list of (opcode, argument) tuples 727 728 source = Tokenizer(str) 729 730 if pattern is None: 731 pattern = Pattern() 732 pattern.flags = flags 733 pattern.str = str 734 735 p = _parse_sub(source, pattern, 0) 736 if (sys.py3kwarning and 737 (p.pattern.flags & SRE_FLAG_LOCALE) and 738 (p.pattern.flags & SRE_FLAG_UNICODE)): 739 import warnings 740 warnings.warnpy3k("LOCALE and UNICODE flags are incompatible", 741 DeprecationWarning, stacklevel=5) 742 743 tail = source.get() 744 if tail == ")": 745 raise error, "unbalanced parenthesis" 746 elif tail: 747 raise error, "bogus characters at end of regular expression" 748 749 if not (flags & SRE_FLAG_VERBOSE) and p.pattern.flags & SRE_FLAG_VERBOSE: 750 # the VERBOSE flag was switched on inside the pattern. to be 751 # on the safe side, we'll parse the whole thing again... 752 return parse(str, p.pattern.flags) 753 754 if flags & SRE_FLAG_DEBUG: 755 p.dump() 756 757 return p 758 759 def parse_template(source, pattern): 760 # parse 're' replacement string into list of literals and 761 # group references 762 s = Tokenizer(source) 763 sget = s.get 764 p = [] 765 a = p.append 766 def literal(literal, p=p, pappend=a): 767 if p and p[-1][0] is LITERAL: 768 p[-1] = LITERAL, p[-1][1] + literal 769 else: 770 pappend((LITERAL, literal)) 771 sep = source[:0] 772 if type(sep) is type(""): 773 makechar = chr 774 else: 775 makechar = unichr 776 while 1: 777 this = sget() 778 if this is None: 779 break # end of replacement string 780 if this and this[0] == "\\": 781 # group 782 c = this[1:2] 783 if c == "g": 784 name = "" 785 if s.match("<"): 786 while 1: 787 char = sget() 788 if char is None: 789 raise error, "unterminated group name" 790 if char == ">": 791 break 792 name = name + char 793 if not name: 794 raise error, "missing group name" 795 try: 796 index = int(name) 797 if index < 0: 798 raise error, "negative group number" 799 except ValueError: 800 if not isname(name): 801 raise error, "bad character in group name" 802 try: 803 index = pattern.groupindex[name] 804 except KeyError: 805 msg = "unknown group name: {0!r}".format(name) 806 raise IndexError(msg) 807 a((MARK, index)) 808 elif c == "0": 809 if s.next in OCTDIGITS: 810 this = this + sget() 811 if s.next in OCTDIGITS: 812 this = this + sget() 813 literal(makechar(int(this[1:], 8) & 0xff)) 814 elif c in DIGITS: 815 isoctal = False 816 if s.next in DIGITS: 817 this = this + sget() 818 if (c in OCTDIGITS and this[2] in OCTDIGITS and 819 s.next in OCTDIGITS): 820 this = this + sget() 821 isoctal = True 822 literal(makechar(int(this[1:], 8) & 0xff)) 823 if not isoctal: 824 a((MARK, int(this[1:]))) 825 else: 826 try: 827 this = makechar(ESCAPES[this][1]) 828 except KeyError: 829 if sys.py3kwarning and c in ASCIILETTERS: 830 import warnings 831 warnings.warnpy3k('bad escape %s' % this, 832 DeprecationWarning, stacklevel=4) 833 literal(this) 834 else: 835 literal(this) 836 # convert template to groups and literals lists 837 i = 0 838 groups = [] 839 groupsappend = groups.append 840 literals = [None] * len(p) 841 for c, s in p: 842 if c is MARK: 843 groupsappend((i, s)) 844 # literal[i] is already None 845 else: 846 literals[i] = s 847 i = i + 1 848 return groups, literals 849 850 def expand_template(template, match): 851 g = match.group 852 sep = match.string[:0] 853 groups, literals = template 854 literals = literals[:] 855 try: 856 for index, group in groups: 857 literals[index] = s = g(group) 858 if s is None: 859 raise error, "unmatched group" 860 except IndexError: 861 raise error, "invalid group reference" 862 return sep.join(literals) 863
