Re: Is it ok to sort a list of overlays destructively?

[Marcin Borkowski <mbork@mbork.pl>]

On 2021-07-27, at 11:40, tomas@tuxteam.de wrote:

> On Tue, Jul 27, 2021 at 07:22:42AM +0200, Marcin Borkowski wrote:
>> Hi all,
>> 
>> I need to sort the list of overlays returned by `overlays-in'.  The docs
>> for that function do not says explicitly that it creates a new list
>> every time, although a cursory glance at its source says that it
>> apparently does.  (Also,
>> 
>> (eq (overlays-in (point-min) (point-max)) (overlays-in (point-min) (point-max)))
>> 
>> is nil also when there are overlays in the buffer, so it seems to be the
>> case.)  OTOH, if creating a new list every time isn't in the docs, one
>> shouldn't rely on it, no?
>> 
>> So, is it a good practice to
>> 
>> (sort (overlays-in (point-min) (point-max))
>>       (lambda (o1 o2)
>> 	(< (overlay-start o1) (overlay-start o2))))
>> 
>> ?
>
> Heh. Good question. I wouldn't, unless the docs said explicitly that it
> makes a fresh list.

Precisely my attitude, but I was curious if it's a good one or only my
OCTD kicking in.

Best,

-- 
Marcin Borkowski
http://mbork.pl