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|
#
# Secret Labs' Regular Expression Engine
#
# re-compatible interface for the sre matching engine
#
# Copyright (c) 1998-2000 by Secret Labs AB. All rights reserved.
#
# Portions of this engine have been developed in cooperation with
# CNRI. Hewlett-Packard provided funding for 2.0 integration and
# other compatibility work.
#
import sre_compile
import sre_parse
# flags
I = IGNORECASE = sre_compile.SRE_FLAG_IGNORECASE
L = LOCALE = sre_compile.SRE_FLAG_LOCALE
M = MULTILINE = sre_compile.SRE_FLAG_MULTILINE
S = DOTALL = sre_compile.SRE_FLAG_DOTALL
X = VERBOSE = sre_compile.SRE_FLAG_VERBOSE
# sre extensions (may or may not be in 2.0 final)
T = TEMPLATE = sre_compile.SRE_FLAG_TEMPLATE
U = UNICODE = sre_compile.SRE_FLAG_UNICODE
# sre exception
error = sre_compile.error
# --------------------------------------------------------------------
# public interface
# FIXME: add docstrings
def match(pattern, string, flags=0):
return _compile(pattern, flags).match(string)
def search(pattern, string, flags=0):
return _compile(pattern, flags).search(string)
def sub(pattern, repl, string, count=0):
return _compile(pattern).sub(repl, string, count)
def subn(pattern, repl, string, count=0):
return _compile(pattern).subn(repl, string, count)
def split(pattern, string, maxsplit=0):
return _compile(pattern).split(string, maxsplit)
def findall(pattern, string, maxsplit=0):
return _compile(pattern).findall(string, maxsplit)
def compile(pattern, flags=0):
return _compile(pattern, flags)
def template(pattern, flags=0):
return _compile(pattern, flags|T)
def escape(pattern):
s = list(pattern)
for i in range(len(pattern)):
c = pattern[i]
if not ("a" <= c <= "z" or "A" <= c <= "Z" or "0" <= c <= "9"):
if c == "\000":
s[i] = "\\000"
else:
s[i] = "\\" + c
return pattern[:0].join(s)
# --------------------------------------------------------------------
# internals
_cache = {}
_MAXCACHE = 100
def _compile(pattern, flags=0):
# internal: compile pattern
tp = type(pattern)
if tp not in (type(""), type(u"")):
return pattern
key = (tp, pattern, flags)
try:
return _cache[key]
except KeyError:
pass
p = sre_compile.compile(pattern, flags)
if len(_cache) >= _MAXCACHE:
_cache.clear()
_cache[key] = p
return p
def purge():
# clear pattern cache
_cache.clear()
def _sub(pattern, template, string, count=0):
# internal: pattern.sub implementation hook
return _subn(pattern, template, string, count)[0]
def _subn(pattern, template, string, count=0):
# internal: pattern.subn implementation hook
if callable(template):
filter = template
else:
template = sre_parse.parse_template(template, pattern)
def filter(match, template=template):
return sre_parse.expand_template(template, match)
n = i = 0
s = []
append = s.append
c = pattern.scanner(string)
while not count or n < count:
m = c.search()
if not m:
break
b, e = m.span()
if i < b:
append(string[i:b])
append(filter(m))
i = e
n = n + 1
append(string[i:])
return string[:0].join(s), n
def _split(pattern, string, maxsplit=0):
# internal: pattern.split implementation hook
n = i = 0
s = []
append = s.append
extend = s.extend
c = pattern.scanner(string)
g = pattern.groups
while not maxsplit or n < maxsplit:
m = c.search()
if not m:
break
b, e = m.span()
if b == e:
if i >= len(string):
break
continue
append(string[i:b])
if g and b != e:
extend(m.groups())
i = e
n = n + 1
append(string[i:])
return s
# register myself for pickling
import copy_reg
def _pickle(p):
return _compile, (p.pattern, p.flags)
copy_reg.pickle(type(_compile("")), _pickle, _compile)
# --------------------------------------------------------------------
# experimental stuff (see python-dev discussions for details)
class Scanner:
def __init__(self, lexicon):
self.lexicon = lexicon
p = []
for phrase, action in lexicon:
p.append("(?:%s)(?P#%d)" % (phrase, len(p)))
self.scanner = _compile("|".join(p))
def scan(self, string):
result = []
append = result.append
match = self.scanner.match
i = 0
while 1:
m = match(string, i)
if not m:
break
j = m.end()
if i == j:
break
action = self.lexicon[m.lastindex][1]
if callable(action):
self.match = match
action = action(self, m.group())
if action is not None:
append(action)
i = j
return result, string[i:]
|
