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

[tomas]

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.

But perhaps I'm too timid :)

Cheers
 - t

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