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Implemented non-recursive SRE matching.

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This commit is contained in:
Gustavo Niemeyer 2003-10-17 22:13:16 +00:00
parent 41e2809feb
commit ad3fc44ccb
9 changed files with 844 additions and 474 deletions
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40
Lib/sre_parse.py
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@ -364,6 +364,20 @@ def _parse_sub(source, state, nested=1):
subpattern.append((BRANCH, (None, items)))
return subpattern
def _parse_sub_cond(source, state, condgroup):
item_yes = _parse(source, state)
if source.match("|"):
item_no = _parse(source, state)
if source.match("|"):
raise error, "conditional backref with more than two branches"
else:
item_no = None
if source.next and not source.match(")", 0):
raise error, "pattern not properly closed"
subpattern = SubPattern(state)
subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))
return subpattern
def _parse(source, state):
# parse a simple pattern
@ -499,6 +513,7 @@ def _parse(source, state):
elif this == "(":
group = 1
name = None
condgroup = None
if source.match("?"):
group = 0
# options
@ -568,6 +583,26 @@ def _parse(source, state):
else:
subpattern.append((ASSERT_NOT, (dir, p)))
continue
elif source.match("("):
# conditional backreference group
condname = ""
while 1:
char = source.get()
if char is None:
raise error, "unterminated name"
if char == ")":
break
condname = condname + char
group = 2
if isname(condname):
condgroup = state.groupdict.get(condname)
if condgroup is None:
raise error, "unknown group name"
else:
try:
condgroup = atoi(condname)
except ValueError:
raise error, "bad character in group name"
else:
# flags
if not source.next in FLAGS:
@ -581,7 +616,10 @@ def _parse(source, state):
group = None
else:
group = state.opengroup(name)
p = _parse_sub(source, state)
if condgroup:
p = _parse_sub_cond(source, state, condgroup)
else:
p = _parse_sub(source, state)
if not source.match(")"):
raise error, "unbalanced parenthesis"
if group is not None: