Matthew Barnett added the comment:
@Tim: the regex module includes some extra checks to reduce the chance of
excessive backtracking. In the case of the OP's example, they seem to be
working. However, it's difficult to know when adding such checks will help, and
your example is one case where
Tim Peters added the comment:
Sure! The OP was obviously asking about the engine that ships with Python, so
that's what I talked about.
Raphaël, Matthew develops an excellent replacement ("regex") for Python's re
module, which you can install via, e.g., "pip install regex" (or, on Windows,
Matthew Barnett added the comment:
You shouldn't assume that just because it takes a long time on one
implementation that it'll take a long time on all of the others, because it's
sometimes possible to include additional checks to reduce the problem. (I doubt
you could eliminate the problem e
Raphaël Riel added the comment:
Thanks Tim! Pretty nice answer that I can learn from! Thanks for your time.
I definitely knew my Regex was broken, yet I was surprised the
interpreter/library didn't gave up/error after some(several million) steps.
Some other language seems to just assume there
Tim Peters added the comment:
Well, the problem in the regexp is this part: "\d+,? ?". You're not
_requiring_ that strings of digits be separated by a comma or blank, you're
only _allowing_ them to be so separated. A solid string of digits is matched
by this, and so the enclosing + require
Raphaël Riel added the comment:
Results for my local computer:
```
Attempting test_01
Done in 0.12ms
Attempting test_02
Done in 1.52ms
Attempting test_03
Done in 26.24ms
Attempting test_04
Done in 432.32ms
Attempting test_05
Done in 886.3ms
Attempting test_06
Done in 1757.07ms
Attempting test_0
New submission from Raphaël Riel :
re won't raise nor return when working with Runaway Regular Expression.
It will compute "almost" indefinitely. Although I'm pretty sure it *may*
complete sometime, it's definetly looks like it's stuck.
```
> python -
Python 3.6.2 (default, Aug 23 2017, 14:
