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Issue #433028: Added support of modifier spans in regular expressions.
This commit is contained in:
Serhiy Storchaka
parent
ee73a65745
commit
be9a4e5c85
7 changed files with 180 additions and 66 deletions
114
Lib/sre_parse.py
114
Lib/sre_parse.py
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@ -65,6 +65,12 @@ FLAGS = {
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"u": SRE_FLAG_UNICODE,
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}
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GLOBAL_FLAGS = (SRE_FLAG_ASCII | SRE_FLAG_LOCALE | SRE_FLAG_UNICODE |
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SRE_FLAG_DEBUG | SRE_FLAG_TEMPLATE)
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class Verbose(Exception):
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pass
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class Pattern:
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# master pattern object. keeps track of global attributes
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def __init__(self):
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@ -184,7 +190,7 @@ class SubPattern:
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lo = lo + i
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hi = hi + j
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elif op is SUBPATTERN:
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i, j = av[1].getwidth()
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i, j = av[-1].getwidth()
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lo = lo + i
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hi = hi + j
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elif op in _REPEATCODES:
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@ -395,7 +401,7 @@ def _escape(source, escape, state):
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pass
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raise source.error("bad escape %s" % escape, len(escape))
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def _parse_sub(source, state, nested=True):
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def _parse_sub(source, state, verbose, nested=True):
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# parse an alternation: a|b|c
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items = []
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@ -403,7 +409,7 @@ def _parse_sub(source, state, nested=True):
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sourcematch = source.match
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start = source.tell()
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while True:
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itemsappend(_parse(source, state))
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itemsappend(_parse(source, state, verbose))
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if not sourcematch("|"):
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break
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@ -445,10 +451,10 @@ def _parse_sub(source, state, nested=True):
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subpattern.append((BRANCH, (None, items)))
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return subpattern
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def _parse_sub_cond(source, state, condgroup):
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item_yes = _parse(source, state)
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def _parse_sub_cond(source, state, condgroup, verbose):
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item_yes = _parse(source, state, verbose)
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if source.match("|"):
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item_no = _parse(source, state)
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item_no = _parse(source, state, verbose)
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if source.next == "|":
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raise source.error("conditional backref with more than two branches")
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else:
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@ -457,7 +463,7 @@ def _parse_sub_cond(source, state, condgroup):
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subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))
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return subpattern
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def _parse(source, state):
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def _parse(source, state, verbose):
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# parse a simple pattern
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subpattern = SubPattern(state)
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@ -467,7 +473,6 @@ def _parse(source, state):
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sourcematch = source.match
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_len = len
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_ord = ord
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verbose = state.flags & SRE_FLAG_VERBOSE
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while True:
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@ -621,6 +626,8 @@ def _parse(source, state):
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group = True
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name = None
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condgroup = None
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add_flags = 0
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del_flags = 0
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if sourcematch("?"):
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# options
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char = sourceget()
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@ -682,7 +689,7 @@ def _parse(source, state):
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lookbehindgroups = state.lookbehindgroups
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if lookbehindgroups is None:
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state.lookbehindgroups = state.groups
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p = _parse_sub(source, state)
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p = _parse_sub(source, state, verbose)
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if dir < 0:
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if lookbehindgroups is None:
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state.lookbehindgroups = None
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@ -718,19 +725,13 @@ def _parse(source, state):
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raise source.error("invalid group reference",
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len(condname) + 1)
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state.checklookbehindgroup(condgroup, source)
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elif char in FLAGS:
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elif char in FLAGS or char == "-":
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# flags
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while True:
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state.flags |= FLAGS[char]
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char = sourceget()
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if char is None:
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raise source.error("missing )")
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if char == ")":
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break
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if char not in FLAGS:
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raise source.error("unknown flag", len(char))
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verbose = state.flags & SRE_FLAG_VERBOSE
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continue
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flags = _parse_flags(source, state, char)
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if flags is None: # global flags
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continue
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add_flags, del_flags = flags
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group = None
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else:
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raise source.error("unknown extension ?" + char,
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len(char) + 1)
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@ -742,15 +743,17 @@ def _parse(source, state):
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except error as err:
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raise source.error(err.msg, len(name) + 1) from None
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if condgroup:
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p = _parse_sub_cond(source, state, condgroup)
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p = _parse_sub_cond(source, state, condgroup, verbose)
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else:
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p = _parse_sub(source, state)
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sub_verbose = ((verbose or (add_flags & SRE_FLAG_VERBOSE)) and
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not (del_flags & SRE_FLAG_VERBOSE))
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p = _parse_sub(source, state, sub_verbose)
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if not source.match(")"):
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raise source.error("missing ), unterminated subpattern",
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source.tell() - start)
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if group is not None:
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state.closegroup(group, p)
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subpatternappend((SUBPATTERN, (group, p)))
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subpatternappend((SUBPATTERN, (group, add_flags, del_flags, p)))
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elif this == "^":
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subpatternappend((AT, AT_BEGINNING))
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@ -763,6 +766,53 @@ def _parse(source, state):
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return subpattern
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def _parse_flags(source, state, char):
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sourceget = source.get
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add_flags = 0
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del_flags = 0
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if char != "-":
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while True:
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add_flags |= FLAGS[char]
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char = sourceget()
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if char is None:
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raise source.error("missing -, : or )")
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if char in ")-:":
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break
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if char not in FLAGS:
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msg = "unknown flag" if char.isalpha() else "missing -, : or )"
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raise source.error(msg, len(char))
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if char == ")":
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if ((add_flags & SRE_FLAG_VERBOSE) and
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not (state.flags & SRE_FLAG_VERBOSE)):
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raise Verbose
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state.flags |= add_flags
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return None
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if add_flags & GLOBAL_FLAGS:
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raise source.error("bad inline flags: cannot turn on global flag", 1)
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if char == "-":
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char = sourceget()
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if char is None:
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raise source.error("missing flag")
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if char not in FLAGS:
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msg = "unknown flag" if char.isalpha() else "missing flag"
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raise source.error(msg, len(char))
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while True:
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del_flags |= FLAGS[char]
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char = sourceget()
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if char is None:
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raise source.error("missing :")
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if char == ":":
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break
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if char not in FLAGS:
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msg = "unknown flag" if char.isalpha() else "missing :"
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raise source.error(msg, len(char))
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assert char == ":"
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if del_flags & GLOBAL_FLAGS:
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raise source.error("bad inline flags: cannot turn off global flag", 1)
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if add_flags & del_flags:
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raise source.error("bad inline flags: flag turned on and off", 1)
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return add_flags, del_flags
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def fix_flags(src, flags):
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# Check and fix flags according to the type of pattern (str or bytes)
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if isinstance(src, str):
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@ -789,18 +839,22 @@ def parse(str, flags=0, pattern=None):
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pattern.flags = flags
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pattern.str = str
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p = _parse_sub(source, pattern, 0)
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try:
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p = _parse_sub(source, pattern, flags & SRE_FLAG_VERBOSE, False)
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except Verbose:
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# the VERBOSE flag was switched on inside the pattern. to be
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# on the safe side, we'll parse the whole thing again...
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pattern = Pattern()
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pattern.flags = flags | SRE_FLAG_VERBOSE
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pattern.str = str
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p = _parse_sub(source, pattern, True, False)
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p.pattern.flags = fix_flags(str, p.pattern.flags)
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if source.next is not None:
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assert source.next == ")"
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raise source.error("unbalanced parenthesis")
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if not (flags & SRE_FLAG_VERBOSE) and p.pattern.flags & SRE_FLAG_VERBOSE:
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# the VERBOSE flag was switched on inside the pattern. to be
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# on the safe side, we'll parse the whole thing again...
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return parse(str, p.pattern.flags)
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if flags & SRE_FLAG_DEBUG:
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p.dump()
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