* re-search-forward hangs
@ 2018-07-30 12:24 Andreas Röhler
2018-07-30 14:33 ` Eli Zaretskii
2018-07-30 17:53 ` Stefan Monnier
0 siblings, 2 replies; 8+ messages in thread
From: Andreas Röhler @ 2018-07-30 12:24 UTC (permalink / raw)
To: Help Gnu Emacs mailing list
Hi,
emacs -Q, when evaluating from in scratch-buffer
(while (re-search-forward "" nil t 1))
Emacs hangs.
Same with plain
(while (search-forward "" nil t 1))
Expect it terminating.
Are there reasons for this?
Thanks,
Andreas
GNU Emacs 27.0.50 (build 1, i686-pc-linux-gnu, GTK+ Version 3.14.5) of
2018-05-29
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: re-search-forward hangs
2018-07-30 12:24 Andreas Röhler
@ 2018-07-30 14:33 ` Eli Zaretskii
2018-07-30 19:29 ` Andreas Röhler
[not found] ` <mailman.4430.1532978809.1292.help-gnu-emacs@gnu.org>
2018-07-30 17:53 ` Stefan Monnier
1 sibling, 2 replies; 8+ messages in thread
From: Eli Zaretskii @ 2018-07-30 14:33 UTC (permalink / raw)
To: help-gnu-emacs
> From: Andreas Röhler <andreas.roehler@easy-emacs.de>
> Date: Mon, 30 Jul 2018 14:24:06 +0200
>
> (while (re-search-forward "" nil t 1))
>
> Emacs hangs.
>
> Same with plain
>
> (while (search-forward "" nil t 1))
>
> Expect it terminating.
>
> Are there reasons for this?
Why did you expect it to terminate?
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: re-search-forward hangs
2018-07-30 14:33 ` Eli Zaretskii
@ 2018-07-30 19:29 ` Andreas Röhler
[not found] ` <mailman.4430.1532978809.1292.help-gnu-emacs@gnu.org>
1 sibling, 0 replies; 8+ messages in thread
From: Andreas Röhler @ 2018-07-30 19:29 UTC (permalink / raw)
To: help-gnu-emacs
On 30.07.2018 16:33, Eli Zaretskii wrote:
>> From: Andreas Röhler <andreas.roehler@easy-emacs.de>
>> Date: Mon, 30 Jul 2018 14:24:06 +0200
>>
>> (while (re-search-forward "" nil t 1))
>>
>> Emacs hangs.
>>
>> Same with plain
>>
>> (while (search-forward "" nil t 1))
>>
>> Expect it terminating.
>>
>> Are there reasons for this?
>
> Why did you expect it to terminate?
>
Expect a call of search-forward from EOB not being successful.
^ permalink raw reply [flat|nested] 8+ messages in thread[parent not found: <mailman.4430.1532978809.1292.help-gnu-emacs@gnu.org>]
* Re: re-search-forward hangs
[not found] ` <mailman.4430.1532978809.1292.help-gnu-emacs@gnu.org>
@ 2018-07-30 19:35 ` Robert Girault
2018-07-30 20:15 ` Andreas Röhler
0 siblings, 1 reply; 8+ messages in thread
From: Robert Girault @ 2018-07-30 19:35 UTC (permalink / raw)
To: help-gnu-emacs
Andreas Röhler <andreas.roehler@easy-emacs.de> writes:
> On 30.07.2018 16:33, Eli Zaretskii wrote:
>>> From: Andreas Röhler <andreas.roehler@easy-emacs.de>
>>> Date: Mon, 30 Jul 2018 14:24:06 +0200
>>>
>>> (while (re-search-forward "" nil t 1))
>>>
>>> Emacs hangs.
>>>
>>> Same with plain
>>>
>>> (while (search-forward "" nil t 1))
>>>
>>> Expect it terminating.
>>>
>>> Are there reasons for this?
>>
>> Why did you expect it to terminate?
>
> Expect a call of search-forward from EOB not being successful.
I see. But searching for the empty string seems to be an always
successful operation as long as you have a string. The empty string is
before or after any character in a string, so I would expect it to be
always found by {re-}search-forward.
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: re-search-forward hangs
2018-07-30 19:35 ` Robert Girault
@ 2018-07-30 20:15 ` Andreas Röhler
0 siblings, 0 replies; 8+ messages in thread
From: Andreas Röhler @ 2018-07-30 20:15 UTC (permalink / raw)
To: help-gnu-emacs
On 30.07.2018 21:35, Robert Girault wrote:
> Andreas Röhler <andreas.roehler@easy-emacs.de> writes:
>
>> On 30.07.2018 16:33, Eli Zaretskii wrote:
>>>> From: Andreas Röhler <andreas.roehler@easy-emacs.de>
>>>> Date: Mon, 30 Jul 2018 14:24:06 +0200
>>>>
>>>> (while (re-search-forward "" nil t 1))
>>>>
>>>> Emacs hangs.
>>>>
>>>> Same with plain
>>>>
>>>> (while (search-forward "" nil t 1))
>>>>
>>>> Expect it terminating.
>>>>
>>>> Are there reasons for this?
>>>
>>> Why did you expect it to terminate?
>>
>> Expect a call of search-forward from EOB not being successful.
>
> I see. But searching for the empty string seems to be an always
> successful operation as long as you have a string. The empty string is
> before or after any character in a string, so I would expect it to be
> always found by {re-}search-forward.
>
Hmm, when trying at BOB with some content, changing the times argument
(message "%s" (search-forward "" nil t 1))
(message "%s" (search-forward "" nil t 2))
(message "%s" (search-forward "" nil t 3))
the result remains "43" - looks like the match is not regular.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: re-search-forward hangs
2018-07-30 12:24 Andreas Röhler
2018-07-30 14:33 ` Eli Zaretskii
@ 2018-07-30 17:53 ` Stefan Monnier
1 sibling, 0 replies; 8+ messages in thread
From: Stefan Monnier @ 2018-07-30 17:53 UTC (permalink / raw)
To: help-gnu-emacs
> emacs -Q, when evaluating from in scratch-buffer
> (while (re-search-forward "" nil t 1))
> Emacs hangs.
It doesn't hang for me. The command doesn't terminate, of course, but
you can interrupt it with C-g.
Stefan
^ permalink raw reply [flat|nested] 8+ messages in thread
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2018-07-30 13:22 ` re-search-forward hangs Robert Girault
2018-07-30 14:36 ` Ben Bacarisse
2018-07-30 12:24 Andreas Röhler
2018-07-30 14:33 ` Eli Zaretskii
2018-07-30 19:29 ` Andreas Röhler
[not found] ` <mailman.4430.1532978809.1292.help-gnu-emacs@gnu.org>
2018-07-30 19:35 ` Robert Girault
2018-07-30 20:15 ` Andreas Röhler
2018-07-30 17:53 ` Stefan Monnier
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