diff options
Diffstat (limited to 'Lib/sre_parse.py')
| -rw-r--r-- | Lib/sre_parse.py | 155 |
1 files changed, 79 insertions, 76 deletions
diff --git a/Lib/sre_parse.py b/Lib/sre_parse.py index 053335a..1b56352 100644 --- a/Lib/sre_parse.py +++ b/Lib/sre_parse.py @@ -25,12 +25,12 @@ CHARMASK = 0xff SPECIAL_CHARS = ".\\[{()*+?^$|" REPEAT_CHARS = "*+?{" -DIGITS = tuple(string.digits) +DIGITS = tuple("012345689") OCTDIGITS = tuple("01234567") HEXDIGITS = tuple("0123456789abcdefABCDEF") -WHITESPACE = tuple(string.whitespace) +WHITESPACE = tuple(" \t\n\r\v\f") ESCAPES = { r"\a": (LITERAL, 7), @@ -68,7 +68,8 @@ FLAGS = { "u": SRE_FLAG_UNICODE, } -class State: +class Pattern: + # master pattern object. keeps track of global attributes def __init__(self): self.flags = 0 self.groups = 1 @@ -88,6 +89,33 @@ class SubPattern: data = [] self.data = data self.width = None + def dump(self, level=0): + nl = 1 + for op, av in self.data: + print level*" " + op,; nl = 0 + if op == "in": + # member sublanguage + print; nl = 1 + for op, a in av: + print (level+1)*" " + op, a + elif op == "branch": + print; nl = 1 + i = 0 + for a in av[1]: + if i > 0: + print level*" " + "or" + a.dump(level+1); nl = 1 + i = i + 1 + elif type(av) in (type(()), type([])): + for a in av: + if isinstance(a, SubPattern): + if not nl: print + a.dump(level+1); nl = 1 + else: + print a, ; nl = 0 + else: + print av, ; nl = 0 + if not nl: print def __repr__(self): return repr(self.data) def __len__(self): @@ -255,10 +283,25 @@ def _escape(source, escape, state): pass raise error, "bogus escape: %s" % repr(escape) -def _branch(pattern, items): - # form a branch operator from a set of items +def _parse_sub(source, state, nested=1): + # parse an alternation: a|b|c - subpattern = SubPattern(pattern) + items = [] + while 1: + items.append(_parse(source, state)) + if source.match("|"): + continue + if not nested: + break + if not source.next or source.match(")"): + break + else: + raise error, "pattern not properly closed" + + if len(items) == 1: + return items[0] + + subpattern = SubPattern(state) # check if all items share a common prefix while 1: @@ -285,7 +328,7 @@ def _branch(pattern, items): break else: # we can store this as a character set instead of a - # branch (FIXME: use a range if possible) + # branch (the compiler may optimize this even more) set = [] for item in items: set.append(item[0]) @@ -296,8 +339,7 @@ def _branch(pattern, items): return subpattern def _parse(source, state): - - # parse regular expression pattern into an operator list. + # parse a simple pattern subpattern = SubPattern(state) @@ -451,22 +493,6 @@ def _parse(source, state): if gid is None: raise error, "unknown group name" subpattern.append((GROUPREF, gid)) - elif source.match("#"): - index = "" - while 1: - char = source.get() - if char is None: - raise error, "unterminated index" - if char == ")": - break - index = index + char - try: - index = int(index) - if index < 0 or index > MAXREPEAT: - raise ValueError - except ValueError: - raise error, "illegal index" - subpattern.append((INDEX, index)) continue else: char = source.get() @@ -491,48 +517,27 @@ def _parse(source, state): raise error, "syntax error" dir = -1 # lookbehind char = source.get() - b = [] - while 1: - p = _parse(source, state) - if source.next == ")": - if b: - b.append(p) - p = _branch(state, b) - if char == "=": - subpattern.append((ASSERT, (dir, p))) - else: - subpattern.append((ASSERT_NOT, (dir, p))) - break - elif source.match("|"): - b.append(p) - else: - raise error, "pattern not properly closed" + p = _parse_sub(source, state) + if char == "=": + subpattern.append((ASSERT, (dir, p))) + else: + subpattern.append((ASSERT_NOT, (dir, p))) + continue else: # flags while FLAGS.has_key(source.next): state.flags = state.flags | FLAGS[source.get()] if group: # parse group contents - b = [] if group == 2: # anonymous group group = None else: group = state.getgroup(name) - while 1: - p = _parse(source, state) - if group is not None: - p.append((INDEX, group)) - if source.match(")"): - if b: - b.append(p) - p = _branch(state, b) - subpattern.append((SUBPATTERN, (group, p))) - break - elif source.match("|"): - b.append(p) - else: - raise error, "group not properly closed" + p = _parse_sub(source, state) + subpattern.append((SUBPATTERN, (group, p))) + if group is not None: + p.append((INDEX, group)) else: while 1: char = source.get() @@ -555,26 +560,24 @@ def _parse(source, state): return subpattern -def parse(pattern, flags=0): +def parse(str, flags=0): # parse 're' pattern into list of (opcode, argument) tuples - source = Tokenizer(pattern) - state = State() - state.flags = flags - b = [] - while 1: - p = _parse(source, state) - tail = source.get() - if tail == "|": - b.append(p) - elif tail == ")": - raise error, "unbalanced parenthesis" - elif tail is None: - if b: - b.append(p) - p = _branch(state, b) - break - else: - raise error, "bogus characters at end of regular expression" + + source = Tokenizer(str) + + pattern = Pattern() + pattern.flags = flags + + p = _parse_sub(source, pattern, 0) + + tail = source.get() + if tail == ")": + raise error, "unbalanced parenthesis" + elif tail: + raise error, "bogus characters at end of regular expression" + + # p.dump() + return p def parse_template(source, pattern): @@ -656,4 +659,4 @@ def expand_template(template, match): if s is None: raise error, "empty group" a(s) - return sep.join(p) + return string.join(p, sep) |