g a pathological regular expression, but rather a problem of
the RE engine that is not optimized to use the faster approach when
possible.
This is well known problem very well explained on:
http://swtch.com/~rsc/regexp/regexp1.html
Cheers,
Franck
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http://mail.python.org/mailman/listinfo/python-list
On Apr 12, 10:31 am, Steven D'Aprano wrote:
> On Sat, 11 Apr 2009 16:46:20 -0700, John Machin wrote:
> > On Apr 12, 3:40 am, Steven D'Aprano > cybersource.com.au> wrote:
> >> On Sat, 11 Apr 2009 08:40:03 -0700, John Machin wrote:
> >> >> To my mind, this is a bug in the RE engine. Is there any re
On Apr 11, 7:31 pm, Steven D'Aprano wrote:
_
> My original test has now been running for close to ten hours now, and
> still can't be interrupted with ctrl-C. However that's in Python 2.5,
> having tried it in Python 2.6.2 they can be interrupted, so I'm satisfied
> that this bug of "regex hangs t
On Sat, 11 Apr 2009 16:46:20 -0700, John Machin wrote:
> On Apr 12, 3:40 am, Steven D'Aprano cybersource.com.au> wrote:
>> On Sat, 11 Apr 2009 08:40:03 -0700, John Machin wrote:
>> >> To my mind, this is a bug in the RE engine. Is there any reason to
>> >> not treat it as a bug?
>>
>> > IMHO it's
On Apr 12, 9:46 am, John Machin wrote:
> result = _re_comments_nc.sub(r"\1", line)
s/_nc// ... that's an artifact of timing it with Non-Capture groups
(?:blahblah) on the two internal groups that don't need to be
capturing (results identical, and no perceptible effect on running
time
On Apr 12, 3:40 am, Steven D'Aprano wrote:
> On Sat, 11 Apr 2009 08:40:03 -0700, John Machin wrote:
> >> To my mind, this is a bug in the RE engine. Is there any reason to not
> >> treat it as a bug?
>
> > IMHO it's not a bug -- s/hang/takes a long time to compute/
>
> > Just look at it: 2 + opera
Steven D'Aprano wrote:
On Sat, 11 Apr 2009 08:40:03 -0700, John Machin wrote:
To my mind, this is a bug in the RE engine. Is there any reason to not
treat it as a bug?
IMHO it's not a bug -- s/hang/takes a long time to compute/
Just look at it: 2 + operators and 3 * operators ... It's one of
On Apr 11, 12:40 pm, Steven D'Aprano wrote:
> On Sat, 11 Apr 2009 08:40:03 -0700, John Machin wrote:
> >> To my mind, this is a bug in the RE engine. Is there any reason to not
> >> treat it as a bug?
>
> > IMHO it's not a bug -- s/hang/takes a long time to compute/
>
> > Just look at it: 2 + oper
> Well, it's been running now for about two and a half hours, that's a
> rather long lunch.
I'd also like a pony!
--
Dotan Cohen
http://what-is-what.com
http://gibberish.co.il
--
http://mail.python.org/mailman/listinfo/python-list
On Sat, 11 Apr 2009 08:40:03 -0700, John Machin wrote:
>> To my mind, this is a bug in the RE engine. Is there any reason to not
>> treat it as a bug?
>
> IMHO it's not a bug -- s/hang/takes a long time to compute/
>
> Just look at it: 2 + operators and 3 * operators ... It's one of those
> "com
On Apr 11, 10:07 am, Steven D'Aprano wrote:
> On Thu, 09 Apr 2009 02:56:00 -0700, David Liang wrote:
> > Hi all,
> > I'm having a weird problem with a regular expression (tested in 2.6 and
> > 3.0):
>
> > Basically, any of these:
> > _re_comments = re.compile(r'^(([^\\]+|\\.|"([^"\\]+|\\.)*")*)#.*
Dotan Cohen wrote:
IMHO it's not a bug -- s/hang/takes a long time to compute/
That is quite what a hang is, and why the timeout was invented. The
real bug is that there is no timeout mechanism.
I wouldn't call it a "hang" because it is actually doing work. If it was
'stuck' on a certain pa
> IMHO it's not a bug -- s/hang/takes a long time to compute/
>
That is quite what a hang is, and why the timeout was invented. The
real bug is that there is no timeout mechanism.
> Just look at it: 2 + operators and 3 * operators ... It's one of those
> "come back after lunch" REs.
>
Some user
On Apr 12, 1:07 am, Steven D'Aprano wrote:
> On Thu, 09 Apr 2009 02:56:00 -0700, David Liang wrote:
> > Hi all,
> > I'm having a weird problem with a regular expression (tested in 2.6 and
> > 3.0):
>
> > Basically, any of these:
> > _re_comments = re.compile(r'^(([^\\]+|\\.|"([^"\\]+|\\.)*")*)#.*$
Steven D'Aprano wrote:
On Thu, 09 Apr 2009 02:56:00 -0700, David Liang wrote:
Hi all,
I'm having a weird problem with a regular expression (tested in 2.6 and
3.0):
Basically, any of these:
_re_comments = re.compile(r'^(([^\\]+|\\.|"([^"\\]+|\\.)*")*)#.*$')
_re_comments = re.compile(r'^(([^#]+|
On Thu, 09 Apr 2009 02:56:00 -0700, David Liang wrote:
> Hi all,
> I'm having a weird problem with a regular expression (tested in 2.6 and
> 3.0):
>
> Basically, any of these:
> _re_comments = re.compile(r'^(([^\\]+|\\.|"([^"\\]+|\\.)*")*)#.*$')
> _re_comments = re.compile(r'^(([^#]+|\\.|"([^"\\]
On Apr 9, 2:56 am, David Liang wrote:
> Hi all,
> I'm having a weird problem with a regular expression (tested in 2.6
> and 3.0):
>
> Basically, any of these:
> _re_comments = re.compile(r'^(([^\\]+|\\.|"([^"\\]+|\\.)*")*)#.*$')
> _re_comments = re.compile(r'^(([^#]+|\\.|"([^"\\]+|\\.)*")*)#.*$')
On Apr 9, 2:56 am, David Liang wrote:
> Hi all,
> I'm having a weird problem with a regular expression (tested in 2.6
> and 3.0):
>
> Basically, any of these:
> _re_comments = re.compile(r'^(([^\\]+|\\.|"([^"\\]+|\\.)*")*)#.*$')
> _re_comments = re.compile(r'^(([^#]+|\\.|"([^"\\]+|\\.)*")*)#.*$')
Hi all,
I'm having a weird problem with a regular expression (tested in 2.6
and 3.0):
Basically, any of these:
_re_comments = re.compile(r'^(([^\\]+|\\.|"([^"\\]+|\\.)*")*)#.*$')
_re_comments = re.compile(r'^(([^#]+|\\.|"([^"\\]+|\\.)*")*)#.*$')
_re_comments = re.compile(r'^(([^"]+|\\.|"([^"\\]+|\
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