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Regexp linting scan
From: |
Mattias Engdegård |
Subject: |
Regexp linting scan |
Date: |
Thu, 30 Jan 2020 17:16:42 +0100 |
Here is a new scan of regexp irregularities in the Emacs tree (master at
1ed7cd41db), using relint 1.13, xr 1.15.
Relint now finds more regexps, and the xr linting engine has a new subsumption
check. This check finds pairs of repetitions, one made unnecessary by the
other, like [ab]+a* or a*a*. The check is somewhat experimental, but is
accurate enough and not only indicates possible mistakes and general waste but
also potential slow regexps.
As an example of the last point, the running time of
(string-match "a*a*b" (make-string N ?a))
is cubical in N. (Not all mistakes are exponential, but it's bad enough.)
relint.log
Description: Binary data
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