From: phs <phs@lsv.fr>
To: "Mattias Engdegård" <mattiase@acm.org>
Cc: Michael Heerdegen <michael_heerdegen@web.de>,
Stefan Monnier <monnier@iro.umontreal.ca>,
emacs-devel@gnu.org
Subject: More re odditie [Was: regular expressions that match nothing]
Date: Thu, 16 May 2019 08:57:18 +0200 [thread overview]
Message-ID: <84fcfdce-39d7-1ebb-c0c7-98aa05854646@lsv.fr> (raw)
In-Reply-To: <128EBFB8-78FF-47C3-8F28-C1EF91BFC4BB@acm.org>
While testing how rx handles the new regexp-unmatchable construct, I
stumbled on some odd emacs behavior.
The regular expression "*", instead of matching zero-or-more occurrences
of the empty string, behaves as "\*" or "[*]" and only matches the *
character.
I believe this is a bug, not a feature, and in any case the Emacs manual
does not document this behavior.
Perhaps it is not a bug in Emacs per se, rather a bug in the gnulib
regex library so I'll wait for comments before submitting a bug report...
If this behavior is the expected one, then (rx (0+ "")) should not
return "*".
We have the same problem with "+" and (rx (1+ "")).
-phs
On 2019/05/15 23:07, Mattias Engdegård wrote:
> 15 maj 2019 kl. 22.17 skrev Michael Heerdegen <michael_heerdegen@web.de>:
>> Should there be an rx regexp form for this?
> We don't necessarily need a special form for it; we can just make `(or)' work.
>
> Proposed patch attached. (I also added its dual, (seq), since it would be silly not to.)
>
next prev parent reply other threads:[~2019-05-16 6:57 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-14 7:25 regular expressions that match nothing philippe schnoebelen
2019-05-14 10:14 ` Mattias Engdegård
2019-05-14 19:41 ` Stefan Monnier
2019-05-15 16:21 ` Mattias Engdegård
2019-05-15 19:41 ` Alan Mackenzie
2019-05-16 10:54 ` Mattias Engdegård
2019-05-16 23:18 ` Phil Sainty
2019-05-17 9:43 ` Alan Mackenzie
2019-05-17 10:17 ` Mattias Engdegård
2019-05-17 12:53 ` Stefan Monnier
2019-05-15 20:17 ` Michael Heerdegen
2019-05-15 21:06 ` Stefan Monnier
2019-05-15 21:07 ` Mattias Engdegård
2019-05-15 21:38 ` Michael Heerdegen
2019-05-16 6:57 ` phs [this message]
2019-05-16 9:29 ` More re odditie [Was: regular expressions that match nothing] Mattias Engdegård
2019-05-16 10:59 ` phs
2019-05-16 12:31 ` Stefan Monnier
2019-05-16 18:35 ` Michael Heerdegen
2019-05-16 20:31 ` Mattias Engdegård
2019-05-16 21:01 ` Global and local definitions of non-functions/variable (was: More re odditie [Was: regular expressions that match nothing]) Stefan Monnier
2019-05-20 16:26 ` Bootstrap/autoload policy (was Re: regular expressions that match nothing) Mattias Engdegård
2019-05-22 14:02 ` Stefan Monnier
2019-05-22 14:07 ` Mattias Engdegård
2019-05-22 14:24 ` Stefan Monnier
2019-05-22 15:06 ` Mattias Engdegård
2019-05-22 15:53 ` Stefan Monnier
2019-05-22 16:40 ` Mattias Engdegård
2019-05-22 19:08 ` Stefan Monnier
2019-05-26 12:05 ` Basil L. Contovounesios
2019-05-16 18:12 ` regular expressions that match nothing Eric Abrahamsen
2019-05-19 4:30 ` 回复: " net june
2019-05-19 5:00 ` HaiJun Zhang
2019-05-19 7:32 ` Mattias Engdegård
2019-05-20 7:56 ` philippe schnoebelen
2019-05-20 23:19 ` Richard Stallman
2019-05-19 14:12 ` 回复: " Drew Adams
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