Subject: bug#58278: Add new function seq-keep

From: Lars Ingebrigtsen <[email-masked]>
Date: Tue, 04 Oct 2022 12:42:50 +0200

Robert Pluim <[email-masked]> writes:

> Well, cl-mapcan applies a function to the elements of a sequence and
> discards 'nil' results. Looks pretty similar to me.

No, it concatenates the results, so the values returned by the function
has to be lists.

But, yes, if you return lists, then nil return values will "disappear".