* bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly
@ 2011-05-11 20:54 Drew Adams
2011-05-12 3:05 ` Stefan Monnier
0 siblings, 1 reply; 8+ messages in thread
From: Drew Adams @ 2011-05-11 20:54 UTC (permalink / raw)
To: 8657
`(next|previous)-single-char-property-change' behaves differently in a
couple of ways from `(next|previous)-single-property-change', besides
the difference of overlay vs text properties.
In particular, IIUC, the return value can never be nil.
Yet I see code such as this:
gnus-summary-show-thread:
(or (next-single-char-property-change end 'invisible) (point-max))
comint-next-prompt:
(setq pos (next-single-char-property-change pos 'field))
(cond (or (null pos)...
Isn't this incorrect?
In GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600)
of 2011-05-10 on 3249CTO
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.5) --no-opt --cflags
-Ic:/build/include'
^ permalink raw reply [flat|nested] 8+ messages in thread
* bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly
2011-05-11 20:54 bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly Drew Adams
@ 2011-05-12 3:05 ` Stefan Monnier
2011-05-12 4:44 ` Eli Zaretskii
0 siblings, 1 reply; 8+ messages in thread
From: Stefan Monnier @ 2011-05-12 3:05 UTC (permalink / raw)
To: Drew Adams; +Cc: 8657
> In particular, IIUC, the return value can never be nil.
> Yet I see code such as this:
> gnus-summary-show-thread:
> (or (next-single-char-property-change end 'invisible) (point-max))
> comint-next-prompt:
> (setq pos (next-single-char-property-change pos 'field))
> (cond (or (null pos)...
> Isn't this incorrect?
The behavior might have changed at some point in time, explaining the
above code.
Stefan
^ permalink raw reply [flat|nested] 8+ messages in thread
* bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly
2011-05-12 3:05 ` Stefan Monnier
@ 2011-05-12 4:44 ` Eli Zaretskii
2011-05-12 13:44 ` bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change'incorrectly Drew Adams
2012-02-06 14:00 ` bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly Chong Yidong
0 siblings, 2 replies; 8+ messages in thread
From: Eli Zaretskii @ 2011-05-12 4:44 UTC (permalink / raw)
To: Stefan Monnier; +Cc: 8657
> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Date: Thu, 12 May 2011 00:05:46 -0300
> Cc: 8657@debbugs.gnu.org
>
> > In particular, IIUC, the return value can never be nil.
> > Yet I see code such as this:
>
> > gnus-summary-show-thread:
> > (or (next-single-char-property-change end 'invisible) (point-max))
>
> > comint-next-prompt:
> > (setq pos (next-single-char-property-change pos 'field))
> > (cond (or (null pos)...
>
> > Isn't this incorrect?
>
> The behavior might have changed at some point in time, explaining the
> above code.
Or maybe the author was confusing next-single-char-property-change
with next-single-property-change.
In any case, those tests are redundant, because
next-single-char-property-change already returns point-max when it
finds no change in properties.
^ permalink raw reply [flat|nested] 8+ messages in thread
* bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change'incorrectly
2011-05-12 4:44 ` Eli Zaretskii
@ 2011-05-12 13:44 ` Drew Adams
2012-02-06 14:00 ` bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly Chong Yidong
1 sibling, 0 replies; 8+ messages in thread
From: Drew Adams @ 2011-05-12 13:44 UTC (permalink / raw)
To: 'Eli Zaretskii', 'Stefan Monnier'; +Cc: 8657
> Or maybe the author was confusing next-single-char-property-change
> with next-single-property-change.
>
> In any case, those tests are redundant, because
> next-single-char-property-change already returns point-max when it
> finds no change in properties.
Yes, what Eli says is what I was suggesting; that's my guess too.
^ permalink raw reply [flat|nested] 8+ messages in thread
* bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly
2011-05-12 4:44 ` Eli Zaretskii
2011-05-12 13:44 ` bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change'incorrectly Drew Adams
@ 2012-02-06 14:00 ` Chong Yidong
2012-02-06 22:56 ` Katsumi Yamaoka
1 sibling, 1 reply; 8+ messages in thread
From: Chong Yidong @ 2012-02-06 14:00 UTC (permalink / raw)
To: Eli Zaretskii; +Cc: 8657
Eli Zaretskii <eliz@gnu.org> writes:
>> The behavior might have changed at some point in time, explaining the
>> above code.
>
> Or maybe the author was confusing next-single-char-property-change
> with next-single-property-change.
>
> In any case, those tests are redundant, because
> next-single-char-property-change already returns point-max when it
> finds no change in properties.
I went ahead and fixed them accordingly.
^ permalink raw reply [flat|nested] 8+ messages in thread
* bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly
2012-02-06 14:00 ` bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly Chong Yidong
@ 2012-02-06 22:56 ` Katsumi Yamaoka
2012-02-07 5:57 ` Chong Yidong
0 siblings, 1 reply; 8+ messages in thread
From: Katsumi Yamaoka @ 2012-02-06 22:56 UTC (permalink / raw)
To: Chong Yidong; +Cc: 8657
Chong Yidong wrote:
> Eli Zaretskii <eliz@gnu.org> writes:
>>> The behavior might have changed at some point in time, explaining the
>>> above code.
>>
>> Or maybe the author was confusing next-single-char-property-change
>> with next-single-property-change.
>>
>> In any case, those tests are redundant, because
>> next-single-char-property-change already returns point-max when it
>> finds no change in properties.
> I went ahead and fixed them accordingly.
But in XEmacs next-single-char-property-change will return nil
if no property change is found. So I've modified the gnus-sum.el
code into:
(if (featurep 'xemacs)
(or (next-single-char-property-change end 'invisible)
(point-max))
(next-single-char-property-change end 'invisible))
^ permalink raw reply [flat|nested] 8+ messages in thread
* bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly
2012-02-06 22:56 ` Katsumi Yamaoka
@ 2012-02-07 5:57 ` Chong Yidong
2012-02-07 6:34 ` Katsumi Yamaoka
0 siblings, 1 reply; 8+ messages in thread
From: Chong Yidong @ 2012-02-07 5:57 UTC (permalink / raw)
To: Katsumi Yamaoka; +Cc: 8657
Katsumi Yamaoka <yamaoka@jpl.org> writes:
> But in XEmacs next-single-char-property-change will return nil
> if no property change is found.
Ah OK, thanks for checking.
> So I've modified the gnus-sum.el code into:
>
> (if (featurep 'xemacs)
> (or (next-single-char-property-change end 'invisible)
> (point-max))
> (next-single-char-property-change end 'invisible))
I suggest just restoring the old code, and adding a comment about why
the `or' is there.
^ permalink raw reply [flat|nested] 8+ messages in thread
* bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly
2012-02-07 5:57 ` Chong Yidong
@ 2012-02-07 6:34 ` Katsumi Yamaoka
0 siblings, 0 replies; 8+ messages in thread
From: Katsumi Yamaoka @ 2012-02-07 6:34 UTC (permalink / raw)
To: Chong Yidong; +Cc: 8657
Chong Yidong wrote:
> Katsumi Yamaoka <yamaoka@jpl.org> writes:
>> But in XEmacs next-single-char-property-change will return nil
>> if no property change is found.
> Ah OK, thanks for checking.
>> So I've modified the gnus-sum.el code into:
>>
>> (if (featurep 'xemacs)
>> (or (next-single-char-property-change end 'invisible)
>> (point-max))
>> (next-single-char-property-change end 'invisible))
> I suggest just restoring the old code, and adding a comment about why
> the `or' is there.
Ok. Done.
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2012-02-07 6:34 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-05-11 20:54 bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly Drew Adams
2011-05-12 3:05 ` Stefan Monnier
2011-05-12 4:44 ` Eli Zaretskii
2011-05-12 13:44 ` bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change'incorrectly Drew Adams
2012-02-06 14:00 ` bug#8657: 24.0.50; Emacs code that seems to use `*-single-char-property-change' incorrectly Chong Yidong
2012-02-06 22:56 ` Katsumi Yamaoka
2012-02-07 5:57 ` Chong Yidong
2012-02-07 6:34 ` Katsumi Yamaoka
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