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v0.8.1
v0.8.1
https://github.com/python/cpython
Tip revision: 74f4bd53e03ded8408bcc2de67cf0f5a4ac5b1a1 authored by Barry Warsaw on 23 February 2012, 15:59:38 UTC
Bump some more copyright years (as per PEP 101), since this is the first
Bump some more copyright years (as per PEP 101), since this is the first
Tip revision: 74f4bd5
scanner.py
"""Iterator based sre token scanner
"""
import re
import sre_parse
import sre_compile
import sre_constants
from re import VERBOSE, MULTILINE, DOTALL
from sre_constants import BRANCH, SUBPATTERN
__all__ = ['Scanner', 'pattern']
FLAGS = (VERBOSE | MULTILINE | DOTALL)
class Scanner(object):
def __init__(self, lexicon, flags=FLAGS):
self.actions = [None]
# Combine phrases into a compound pattern
s = sre_parse.Pattern()
s.flags = flags
p = []
for idx, token in enumerate(lexicon):
phrase = token.pattern
try:
subpattern = sre_parse.SubPattern(s,
[(SUBPATTERN, (idx + 1, sre_parse.parse(phrase, flags)))])
except sre_constants.error:
raise
p.append(subpattern)
self.actions.append(token)
s.groups = len(p) + 1 # NOTE(guido): Added to make SRE validation work
p = sre_parse.SubPattern(s, [(BRANCH, (None, p))])
self.scanner = sre_compile.compile(p)
def iterscan(self, string, idx=0, context=None):
"""Yield match, end_idx for each match
"""
match = self.scanner.scanner(string, idx).match
actions = self.actions
lastend = idx
end = len(string)
while True:
m = match()
if m is None:
break
matchbegin, matchend = m.span()
if lastend == matchend:
break
action = actions[m.lastindex]
if action is not None:
rval, next_pos = action(m, context)
if next_pos is not None and next_pos != matchend:
# "fast forward" the scanner
matchend = next_pos
match = self.scanner.scanner(string, matchend).match
yield rval, matchend
lastend = matchend
def pattern(pattern, flags=FLAGS):
def decorator(fn):
fn.pattern = pattern
fn.regex = re.compile(pattern, flags)
return fn
return decorator