Re: cl-delete-if vs list of overlays

[Omar Polo]

Thien-Thi Nguyen <ttn@gnuvola.org> writes:

> () Omar Polo <op@omarpolo.com>
> () Wed, 09 Dec 2020 10:53:26 +0100
>
>    Why is cl-delete-if not removing items from the list?  (setq
>    delp t) evaluates to t, so it should delete.  cl-delete-if a
>    destructive function.  This is what I'm not getting.
>
> On my system, ‘C-h f cl-delete-if RET’ sez:
>
>  This is a destructive function; it reuses the storage of SEQ
>  whenever possible.
>
> So, your question becomes: When is it NOT possible to reuse the
> storage of SEQ in the process of deleting an item?

Oh my, I feel so stupid now...

I was under the (wrong) assumption that a destructive function will
always modify the list, when it's not the case.  I needed to setq the
result of cl-delete-if to the list itself to cover all the cases.

Thanks!