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Added Fredrik Lundh's sre module and its supporting cast. 

NOTE: THIS IS VERY ROUGH ALPHA CODE!
This commit is contained in:
Guido van Rossum 2000-03-31 14:58:54 +00:00
parent 7a5b796322
commit 7627c0de69
4 changed files with 856 additions and 0 deletions
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46
Lib/sre.py Normal file
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# -*- Mode: Python; tab-width: 4 -*-
#
# Secret Labs' Regular Expression Engine
# $Id$
#
# re-compatible interface for the sre matching engine
#
# Copyright (c) 1998-2000 by Secret Labs AB. All rights reserved.
#
# This code can only be used for 1.6 alpha testing. All other use
# require explicit permission from Secret Labs AB.
#
# Portions of this engine have been developed in cooperation with
# CNRI. Hewlett-Packard provided funding for 1.6 integration and
# other compatibility work.
#
"""
this is a long string
"""
import sre_compile
# --------------------------------------------------------------------
# public interface
def compile(pattern, flags=0):
return sre_compile.compile(pattern, _fixflags(flags))
def match(pattern, string, flags=0):
return compile(pattern, _fixflags(flags)).match(string)
def search(pattern, string, flags=0):
assert flags == 0
return compile(pattern, _fixflags(flags)).search(string)
# FIXME: etc
# --------------------------------------------------------------------
# helpers
def _fixflags(flags):
# convert flag bitmask to sequence
assert flags == 0
return ()

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#
# Secret Labs' Regular Expression Engine
# $Id$
#
# convert template to internal format
#
# Copyright (c) 1997-2000 by Secret Labs AB. All rights reserved.
#
# This code can only be used for 1.6 alpha testing. All other use
# require explicit permission from Secret Labs AB.
#
# Portions of this engine have been developed in cooperation with
# CNRI. Hewlett-Packard provided funding for 1.6 integration and
# other compatibility work.
#
# FIXME: <fl> formalize (objectify?) and document the compiler code
# format, so that other frontends can use this compiler
import array, string, sys
import _sre
from sre_constants import *
# find an array type code that matches the engine's code size
for WORDSIZE in "BHil":
if len(array.array(WORDSIZE, [0]).tostring()) == _sre.getcodesize():
break
else:
raise RuntimeError, "cannot find a useable array type"
# FIXME: <fl> should move some optimizations from the parser to here!
class Code:
def __init__(self):
self.data = []
def __len__(self):
return len(self.data)
def __getitem__(self, index):
return self.data[index]
def __setitem__(self, index, code):
self.data[index] = code
def append(self, code):
self.data.append(code)
def todata(self):
# print self.data
return array.array(WORDSIZE, self.data).tostring()
def _lower(literal):
# return _sre._lower(literal) # FIXME
return string.lower(literal)
def _compile(code, pattern, flags):
append = code.append
for op, av in pattern:
if op is ANY:
if "s" in flags:
append(CODES[op]) # any character at all!
else:
append(CODES[NOT_LITERAL])
append(10)
elif op in (SUCCESS, FAILURE):
append(CODES[op])
elif op is AT:
append(CODES[op])
append(POSITIONS[av])
elif op is BRANCH:
append(CODES[op])
tail = []
for av in av[1]:
skip = len(code); append(0)
_compile(code, av, flags)
append(CODES[JUMP])
tail.append(len(code)); append(0)
code[skip] = len(code) - skip
append(0) # end of branch
for tail in tail:
code[tail] = len(code) - tail
elif op is CALL:
append(CODES[op])
skip = len(code); append(0)
_compile(code, av, flags)
append(CODES[SUCCESS])
code[skip] = len(code) - skip
elif op is CATEGORY: # not used by current parser
append(CODES[op])
append(CATEGORIES[av])
elif op is GROUP:
if "i" in flags:
append(CODES[MAP_IGNORE[op]])
else:
append(CODES[op])
append(av)
elif op is IN:
if "i" in flags:
append(CODES[MAP_IGNORE[op]])
def fixup(literal):
return ord(_lower(literal))
else:
append(CODES[op])
fixup = ord
skip = len(code); append(0)
for op, av in av:
append(CODES[op])
if op is NEGATE:
pass
elif op is LITERAL:
append(fixup(av))
elif op is RANGE:
append(fixup(av[0]))
append(fixup(av[1]))
elif op is CATEGORY:
append(CATEGORIES[av])
else:
raise ValueError, "unsupported set operator"
append(CODES[FAILURE])
code[skip] = len(code) - skip
elif op in (LITERAL, NOT_LITERAL):
if "i" in flags:
append(CODES[MAP_IGNORE[op]])
append(ord(_lower(av)))
else:
append(CODES[op])
append(ord(av))
elif op is MARK:
append(CODES[op])
append(av)
elif op in (REPEAT, MIN_REPEAT, MAX_REPEAT):
lo, hi = av[2].getwidth()
if lo == 0:
raise SyntaxError, "cannot repeat zero-width items"
if lo == hi == 1 and op is MAX_REPEAT:
append(CODES[MAX_REPEAT_ONE])
skip = len(code); append(0)
append(av[0])
append(av[1])
_compile(code, av[2], flags)
append(CODES[SUCCESS])
code[skip] = len(code) - skip
else:
append(CODES[op])
skip = len(code); append(0)
append(av[0])
append(av[1])
_compile(code, av[2], flags)
if op is MIN_REPEAT:
append(CODES[MIN_UNTIL])
else:
# FIXME: MAX_REPEAT PROBABLY DOESN'T WORK (?)
append(CODES[MAX_UNTIL])
code[skip] = len(code) - skip
elif op is SUBPATTERN:
## group = av[0]
## if group:
## append(CODES[MARK])
## append((group-1)*2)
_compile(code, av[1], flags)
## if group:
## append(CODES[MARK])
## append((group-1)*2+1)
else:
raise ValueError, ("unsupported operand type", op)
def compile(p, flags=()):
# convert pattern list to internal format
if type(p) is type(""):
import sre_parse
pattern = p
p = sre_parse.parse(p)
else:
pattern = None
# print p.getwidth()
# print p
code = Code()
_compile(code, p.data, p.pattern.flags)
code.append(CODES[SUCCESS])
# print list(code.data)
data = code.todata()
if 0: # debugging
print
print "-" * 68
import sre_disasm
sre_disasm.disasm(data)
print "-" * 68
# print len(data), p.pattern.groups, len(p.pattern.groupdict)
return _sre.compile(pattern, data, p.pattern.groups-1, p.pattern.groupdict)

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#
# Secret Labs' Regular Expression Engine
# $Id$
#
# various symbols used by the regular expression engine.
# run this script to update the _sre include files!
#
# Copyright (c) 1998-2000 by Secret Labs AB. All rights reserved.
#
# This code can only be used for 1.6 alpha testing. All other use
# require explicit permission from Secret Labs AB.
#
# Portions of this engine have been developed in cooperation with
# CNRI. Hewlett-Packard provided funding for 1.6 integration and
# other compatibility work.
#
# operators
FAILURE = "failure"
SUCCESS = "success"
ANY = "any"
ASSERT = "assert"
AT = "at"
BRANCH = "branch"
CALL = "call"
CATEGORY = "category"
GROUP = "group"
GROUP_IGNORE = "group_ignore"
IN = "in"
IN_IGNORE = "in_ignore"
JUMP = "jump"
LITERAL = "literal"
LITERAL_IGNORE = "literal_ignore"
MARK = "mark"
MAX_REPEAT = "max_repeat"
MAX_REPEAT_ONE = "max_repeat_one"
MAX_UNTIL = "max_until"
MIN_REPEAT = "min_repeat"
MIN_UNTIL = "min_until"
NEGATE = "negate"
NOT_LITERAL = "not_literal"
NOT_LITERAL_IGNORE = "not_literal_ignore"
RANGE = "range"
REPEAT = "repeat"
SUBPATTERN = "subpattern"
# positions
AT_BEGINNING = "at_beginning"
AT_BOUNDARY = "at_boundary"
AT_NON_BOUNDARY = "at_non_boundary"
AT_END = "at_end"
# categories
CATEGORY_DIGIT = "category_digit"
CATEGORY_NOT_DIGIT = "category_not_digit"
CATEGORY_SPACE = "category_space"
CATEGORY_NOT_SPACE = "category_not_space"
CATEGORY_WORD = "category_word"
CATEGORY_NOT_WORD = "category_not_word"
CODES = [
# failure=0 success=1 (just because it looks better that way :-)
FAILURE, SUCCESS,
ANY,
ASSERT,
AT,
BRANCH,
CALL,
CATEGORY,
GROUP, GROUP_IGNORE,
IN, IN_IGNORE,
JUMP,
LITERAL, LITERAL_IGNORE,
MARK,
MAX_REPEAT, MAX_UNTIL,
MAX_REPEAT_ONE,
MIN_REPEAT, MIN_UNTIL,
NOT_LITERAL, NOT_LITERAL_IGNORE,
NEGATE,
RANGE,
REPEAT
]
# convert to dictionary
c = {}
i = 0
for code in CODES:
c[code] = i
i = i + 1
CODES = c
# replacement operations for "ignore case" mode
MAP_IGNORE = {
GROUP: GROUP_IGNORE,
IN: IN_IGNORE,
LITERAL: LITERAL_IGNORE,
NOT_LITERAL: NOT_LITERAL_IGNORE
}
POSITIONS = {
AT_BEGINNING: ord("a"),
AT_BOUNDARY: ord("b"),
AT_NON_BOUNDARY: ord("B"),
AT_END: ord("z"),
}
CATEGORIES = {
CATEGORY_DIGIT: ord("d"),
CATEGORY_NOT_DIGIT: ord("D"),
CATEGORY_SPACE: ord("s"),
CATEGORY_NOT_SPACE: ord("S"),
CATEGORY_WORD: ord("w"),
CATEGORY_NOT_WORD: ord("W"),
}
if __name__ == "__main__":
import string
items = CODES.items()
items.sort(lambda a, b: cmp(a[1], b[1]))
f = open("sre_constants.h", "w")
f.write("/* generated by sre_constants.py */\n")
for k, v in items:
f.write("#define SRE_OP_" + string.upper(k) + " " + str(v) + "\n")
f.close()
print "done"

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#
# Secret Labs' Regular Expression Engine
# $Id$
#
# convert re-style regular expression to SRE template. the current
# implementation is somewhat incomplete, and not very fast. should
# definitely be rewritten before Python 1.6 goes beta.
#
# Copyright (c) 1998-2000 by Secret Labs AB. All rights reserved.
#
# This code can only be used for 1.6 alpha testing. All other use
# require explicit permission from Secret Labs AB.
#
# Portions of this engine have been developed in cooperation with
# CNRI. Hewlett-Packard provided funding for 1.6 integration and
# other compatibility work.
#
# FIXME: comments marked with the FIXME tag are open issues. all such
# issues should be closed before the final beta.
import string, sys
from sre_constants import *
SPECIAL_CHARS = ".\\[{()*+?^$|"
REPEAT_CHARS = "*+?{"
OCTDIGITS = "01234567"
HEXDIGITS = "0123456789abcdefABCDEF"
ESCAPES = {
"\\a": (LITERAL, chr(7)),
"\\b": (LITERAL, chr(8)),
"\\f": (LITERAL, chr(12)),
"\\n": (LITERAL, chr(10)),
"\\r": (LITERAL, chr(13)),
"\\t": (LITERAL, chr(9)),
"\\v": (LITERAL, chr(11))
}
CATEGORIES = {
"\\A": (AT, AT_BEGINNING), # start of string
"\\b": (AT, AT_BOUNDARY),
"\\B": (AT, AT_NON_BOUNDARY),
"\\d": (IN, [(CATEGORY, CATEGORY_DIGIT)]),
"\\D": (IN, [(CATEGORY, CATEGORY_NOT_DIGIT)]),
"\\s": (IN, [(CATEGORY, CATEGORY_SPACE)]),
"\\S": (IN, [(CATEGORY, CATEGORY_NOT_SPACE)]),
"\\w": (IN, [(CATEGORY, CATEGORY_WORD)]),
"\\W": (IN, [(CATEGORY, CATEGORY_NOT_WORD)]),
"\\Z": (AT, AT_END), # end of string
}
class Pattern:
# FIXME: <fl> rename class, and store flags in here too!
def __init__(self):
self.flags = []
self.groups = 1
self.groupdict = {}
def getgroup(self, name=None):
gid = self.groups
self.groups = gid + 1
if name:
self.groupdict[name] = gid
return gid
def setflag(self, flag):
if flag not in self.flags:
self.flags.append(flag)
class SubPattern:
# a subpattern, in intermediate form
def __init__(self, pattern, data=None):
self.pattern = pattern
if not data:
data = []
self.data = data
self.flags = []
self.width = None
def __repr__(self):
return repr(self.data)
def __len__(self):
return len(self.data)
def __delitem__(self, index):
del self.data[index]
def __getitem__(self, index):
return self.data[index]
def __setitem__(self, index, code):
self.data[index] = code
def __getslice__(self, start, stop):
return SubPattern(self.pattern, self.data[start:stop])
def insert(self, index, code):
self.data.insert(index, code)
def append(self, code):
self.data.append(code)
def getwidth(self):
# determine the width (min, max) for this subpattern
if self.width:
return self.width
lo = hi = 0L
for op, av in self.data:
if op is BRANCH:
l = sys.maxint
h = 0
for av in av[1]:
i, j = av.getwidth()
l = min(l, i)
h = min(h, j)
lo = lo + i
hi = hi + j
elif op is CALL:
i, j = av.getwidth()
lo = lo + i
hi = hi + j
elif op is SUBPATTERN:
i, j = av[1].getwidth()
lo = lo + i
hi = hi + j
elif op in (MIN_REPEAT, MAX_REPEAT):
i, j = av[2].getwidth()
lo = lo + i * av[0]
hi = hi + j * av[1]
elif op in (ANY, RANGE, IN, LITERAL, NOT_LITERAL, CATEGORY):
lo = lo + 1
hi = hi + 1
elif op == SUCCESS:
break
self.width = int(min(lo, sys.maxint)), int(min(hi, sys.maxint))
return self.width
def set(self, flag):
if not flag in self.flags:
self.flags.append(flag)
def reset(self, flag):
if flag in self.flags:
self.flags.remove(flag)
class Tokenizer:
def __init__(self, string):
self.string = list(string)
self.next = self.__next()
def __next(self):
if not self.string:
return None
char = self.string[0]
if char[0] == "\\":
try:
c = self.string[1]
except IndexError:
raise SyntaxError, "bogus escape"
char = char + c
try:
if c == "x":
# hexadecimal constant
for i in xrange(2, sys.maxint):
c = self.string[i]
if c not in HEXDIGITS:
break
char = char + c
elif c in string.digits:
# decimal (or octal) number
for i in xrange(2, sys.maxint):
c = self.string[i]
# FIXME: if larger than current number of
# groups, interpret as an octal number
if c not in string.digits:
break
char = char + c
except IndexError:
pass # use what we've got this far
del self.string[0:len(char)]
return char
def match(self, char):
if char == self.next:
self.next = self.__next()
return 1
return 0
def match_set(self, set):
if self.next in set:
self.next = self.__next()
return 1
return 0
def get(self):
this = self.next
self.next = self.__next()
return this
def _fixescape(escape, character_class=0):
# convert escape to (type, value)
if character_class:
# inside a character class, we'll look in the character
# escapes dictionary first
code = ESCAPES.get(escape)
if code:
return code
code = CATEGORIES.get(escape)
else:
code = CATEGORIES.get(escape)
if code:
return code
code = ESCAPES.get(escape)
if code:
return code
if not character_class:
try:
group = int(escape[1:])
# FIXME: only valid if group <= current number of groups
return GROUP, group
except ValueError:
pass
try:
if escape[1:2] == "x":
escape = escape[2:]
return LITERAL, chr(string.atoi(escape[-2:], 16) & 0xff)
elif escape[1:2] in string.digits:
return LITERAL, chr(string.atoi(escape[1:], 8) & 0xff)
elif len(escape) == 2:
return LITERAL, escape[1]
except ValueError:
pass
raise SyntaxError, "bogus escape: %s" % repr(escape)
def _branch(subpattern, items):
# form a branch operator from a set of items (FIXME: move this
# optimization to the compiler module!)
# check if all items share a common prefix
while 1:
prefix = None
for item in items:
if not item:
break
if prefix is None:
prefix = item[0]
elif item[0] != prefix:
break
else:
# all subitems start with a common "prefix".
# move it out of the branch
for item in items:
del item[0]
subpattern.append(prefix)
continue # check next one
break
# check if the branch can be replaced by a character set
for item in items:
if len(item) != 1 or item[0][0] != LITERAL:
break
else:
# we can store this as a character set instead of a
# branch (FIXME: use a range if possible)
set = []
for item in items:
set.append(item[0])
subpattern.append((IN, set))
return
subpattern.append((BRANCH, (None, items)))
def _parse(source, pattern, flags=()):
# parse regular expression pattern into an operator list.
subpattern = SubPattern(pattern)
this = None
while 1:
if source.next in ("|", ")"):
break # end of subpattern
this = source.get()
if this is None:
break # end of pattern
if this and this[0] not in SPECIAL_CHARS:
subpattern.append((LITERAL, this))
elif this == "[":
# character set
set = []
## if source.match(":"):
## pass # handle character classes
if source.match("^"):
set.append((NEGATE, None))
# check remaining characters
start = set[:]
while 1:
this = source.get()
if this == "]" and set != start:
break
elif this and this[0] == "\\":
code1 = _fixescape(this, 1)
elif this:
code1 = LITERAL, this
else:
raise SyntaxError, "unexpected end of regular expression"
if source.match("-"):
# potential range
this = source.get()
if this == "]":
set.append(code1)
set.append((LITERAL, "-"))
break
else:
if this[0] == "\\":
code2 = _fixescape(this, 1)
else:
code2 = LITERAL, this
if code1[0] != LITERAL or code2[0] != LITERAL:
raise SyntaxError, "illegal range"
if len(code1[1]) != 1 or len(code2[1]) != 1:
raise SyntaxError, "illegal range"
set.append((RANGE, (code1[1], code2[1])))
else:
if code1[0] is IN:
code1 = code1[1][0]
set.append(code1)
# FIXME: <fl> move set optimization to support function
if len(set)==1 and set[0][0] is LITERAL:
subpattern.append(set[0]) # optimization
elif len(set)==2 and set[0][0] is NEGATE and set[1][0] is LITERAL:
subpattern.append((NOT_LITERAL, set[1][1])) # optimization
else:
# FIXME: <fl> add charmap optimization
subpattern.append((IN, set))
elif this and this[0] in REPEAT_CHARS:
# repeat previous item
if this == "?":
min, max = 0, 1
elif this == "*":
min, max = 0, sys.maxint
elif this == "+":
min, max = 1, sys.maxint
elif this == "{":
min, max = 0, sys.maxint
lo = hi = ""
while source.next in string.digits:
lo = lo + source.get()
if source.match(","):
while source.next in string.digits:
hi = hi + source.get()
else:
hi = lo
if not source.match("}"):
raise SyntaxError, "bogus range"
if lo:
min = int(lo)
if hi:
max = int(hi)
# FIXME: <fl> check that hi >= lo!
else:
raise SyntaxError, "not supported"
# figure out which item to repeat
# FIXME: should back up to the right mark, right?
if subpattern:
index = len(subpattern)-1
while subpattern[index][0] is MARK:
index = index - 1
item = subpattern[index:index+1]
else:
raise SyntaxError, "nothing to repeat"
if source.match("?"):
subpattern[index] = (MIN_REPEAT, (min, max, item))
else:
subpattern[index] = (MAX_REPEAT, (min, max, item))
elif this == ".":
subpattern.append((ANY, None))
elif this == "(":
group = 1
name = None
if source.match("?"):
group = 0
# options
if source.match("P"):
# named group: skip forward to end of name
if source.match("<"):
name = ""
while 1:
char = source.get()
if char in (">", None):
break
name = name + char
group = 1
elif source.match(":"):
# non-capturing group
group = 2
elif source.match_set("iI"):
pattern.setflag("i")
elif source.match_set("lL"):
pattern.setflag("l")
elif source.match_set("mM"):
pattern.setflag("m")
elif source.match_set("sS"):
pattern.setflag("s")
elif source.match_set("xX"):
pattern.setflag("x")
if group:
# parse group contents
b = []
if group == 2:
# anonymous group
group = None
else:
group = pattern.getgroup(name)
if group:
subpattern.append((MARK, (group-1)*2))
while 1:
p = _parse(source, pattern, flags)
if source.match(")"):
if b:
b.append(p)
_branch(subpattern, b)
else:
subpattern.append((SUBPATTERN, (group, p)))
break
elif source.match("|"):
b.append(p)
else:
raise SyntaxError, "group not properly closed"
if group:
subpattern.append((MARK, (group-1)*2+1))
else:
# FIXME: should this really be a while loop?
while source.get() not in (")", None):
pass
elif this == "^":
subpattern.append((AT, AT_BEGINNING))
elif this == "$":
subpattern.append((AT, AT_END))
elif this and this[0] == "\\":
code =_fixescape(this)
subpattern.append(code)
else:
raise SyntaxError, "parser error"
return subpattern
def parse(source, flags=()):
s = Tokenizer(source)
g = Pattern()
b = []
while 1:
p = _parse(s, g, flags)
tail = s.get()
if tail == "|":
b.append(p)
elif tail == ")":
raise SyntaxError, "unbalanced parenthesis"
elif tail is None:
if b:
b.append(p)
p = SubPattern(g)
_branch(p, b)
break
else:
raise SyntaxError, "bogus characters at end of regular expression"
return p
if __name__ == "__main__":
from pprint import pprint
from testpatterns import PATTERNS
a = b = c = 0
for pattern, flags in PATTERNS:
if flags:
continue
print "-"*68
try:
p = parse(pattern)
print repr(pattern), "->"
pprint(p.data)
import sre_compile
try:
code = sre_compile.compile(p)
c = c + 1
except:
pass
a = a + 1
except SyntaxError, v:
print "**", repr(pattern), v
b = b + 1
print "-"*68
print a, "of", b, "patterns successfully parsed"
print c, "of", b, "patterns successfully compiled"