[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
bug#19873: Ill-formed regular expression is constructed in forward-parag
From: |
Lars Ingebrigtsen |
Subject: |
bug#19873: Ill-formed regular expression is constructed in forward-paragraph. |
Date: |
Fri, 03 Dec 2021 17:15:18 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) |
Alan Mackenzie <acm@muc.de> writes:
> Back when the bug was new, I started writing a library to analyse a
> regular expression and convert it into an equivalent well formed regular
> expression. It's actually working, but is incomplete. It's currently
> 2757 lines long, including pretty complete unit testing. I actually
> looked at it again at the start of November.
Interesting.
> It strikes me as one of these things which needs to be done
> systematically, which, as I said, I've already tried (and not yet given
> up). The question presents itself, would the effort be better spent
> improving Emacs's regexp engine?
Indeed -- making the Emacs regexp engine transform these complex regexps
into simpler, equivalent forms would be great. We wouldn't have to use
it on all regexps -- the problem usually rears its head when we're
combining several user-defined regexps into a large one, so if we had a
`simplify-regexp' function that we could stick in here, that'd solve the
issue here (and in similar circumstances elsewhere).
--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog: http://lars.ingebrigtsen.no