| msg11418 - (view) |
Author: Pedro Rodriguez (pedro_rodriguez) |
Date: 2002-07-01 18:22 |
| The following expression (?P.*) and (?P(.*)) don't behave in the same way. When the matching fails, the first group will be None, but the last one will contain an empty string. The problem occurs with python 2.1.1 and 2.2. (and latest CVS for 2.3) Python 1.5.2 OTH works fine. (example file attached) |
|
|
| msg11419 - (view) |
Author: Tim Peters (tim.peters) *  |
Date: 2002-07-01 18:36 |
| Logged In: YES user_id=31435 Here's a simpler example: import re pat1 = re.compile(r"((.*)x)?(y)") pat2 = re.compile(r"(((.*))x)?(y)") print pat1.match('y').groups() print pat2.match('y').groups() That prints (None, None, 'y') (None, '', None, 'y') If (y) in the regexps is changed to plain y: pat1 = re.compile(r"((.*)x)?y") pat2 = re.compile(r"(((.*))x)?y") print pat1.match('y').groups() print pat2.match('y').groups() the output changes to (the expected): (None, None) (None, None, None) So it's not *just* the extra level of parens -- whether there's a capturing group "to the right" also affects the outcome. FWIW, I agree it's a buglet. |
|
|
| msg11420 - (view) |
Author: Greg Chapman (glchapman) |
Date: 2002-07-07 16:09 |
| Logged In: YES user_id=86307 I believe this is another example of the bug at which Patch 527371 was aimed. With that patch applied to the 2.2.1 _sre.c, I get this: >>> pat2 = re.compile(r"(((.*))x)?(y)") >>> print pat2.match('y').groups() (None, None, None, 'y') I see that the patch is marked as accepted, but it does not yet appear to have made it into _sre.c even in CVS (at least it's not in version 2.80). Perhaps this is an oversight? |
|
|
| msg11421 - (view) |
Author: Pedro Rodriguez (pedro_rodriguez) |
Date: 2002-07-09 07:20 |
| Logged In: YES user_id=426450 Greg, I tried your patch and it fixes the problems as Tim and myself reported them. If each time the 'lastmark' field is set to a value which is less than the current one, the 'memset' operation should be performed, your patch makes sense IMO, and is consistent with other places in the code. |
|
|
| msg11422 - (view) |
Author: Fredrik Lundh (effbot) * |
Date: 2002-07-12 11:09 |
| Logged In: YES user_id=38376 Makes sense to me. I'll check it in soonish. Thanks /F |
|
|
| msg11423 - (view) |
Author: Michael Stone (mbrierst) |
Date: 2003-02-05 01:07 |
| Logged In: YES user_id=670441 This was fixed when patch 527371 was checked in. Someone close this bug. |
|
|
| msg11424 - (view) |
Author: Fredrik Lundh (effbot) * |
Date: 2003-02-05 08:06 |
| Logged In: YES user_id=38376 Done. Thanks /F |
|
|