Message304197
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, "python -m pip install regex"). More info here:
https://pypi.python.org/pypi/regex/
Matthew, will that become Python's standard offering some day? I'd be in favor of that! It has many advantages, although it doesn't always avoid exponential-time backtracking in failing cases. For example, `re` and `regex` both take exponential time to fail to match the regexp:
"((xy)+)+$"
against strings of the form:
"xy" * i + "y"
Increase `i` by 1, and both take about twice as long to fail to match (meaning either .match or .search), and `re` is actually quicker on my box (3.6.3 on 64-bit Win10).
In any case, I'm closing this, since there's no concrete idea on the table for a change to `re` that would actually help (e.g., people ignore warnings, and there's really no way to _guess_ whether a regexp is "taking too long" to begin with - if it's taking minutes, people immediately discover the hangup already when they interrupt the program and see that it's trying to match a regexp). |
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| Date |
User |
Action |
Args |
| 2017-10-12 01:52:17 | tim.peters | set | recipients:
+ tim.peters, ezio.melotti, mrabarnett, Raphaël Riel |
| 2017-10-12 01:52:17 | tim.peters | set | messageid: <1507773137.38.0.213398074469.issue31759@psf.upfronthosting.co.za> |
| 2017-10-12 01:52:17 | tim.peters | link | issue31759 messages |
| 2017-10-12 01:52:16 | tim.peters | create | |
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