From: Lars Ingebrigtsen <larsi@gnus.org>
To: Jonas Bernoulli <jonas@bernoul.li>
Cc: 58278@debbugs.gnu.org
Subject: bug#58278: Add new function seq-keep
Date: Tue, 04 Oct 2022 01:47:59 +0200 [thread overview]
Message-ID: <87pmf84ggg.fsf@gnus.org> (raw)
In-Reply-To: <87y1twtx22.fsf@bernoul.li> (Jonas Bernoulli's message of "Mon, 03 Oct 2022 23:30:13 +0200")
Jonas Bernoulli <jonas@bernoul.li> writes:
> Unfortunately I cannot find a replacement for `-keep', which I have been
> using a lot. I propose that we add something like:
>
> (cl-defgeneric seq-keep (pred sequence)
> "Return a list of all non-nil results of (PRED element) for elements in SEQUENCE."
> (delq nil (seq-map (lambda (elt) (funcall pred elt))
> sequence)))
Hm... well, here PRED isn't a predicate, really, but a transforming
function? But you wish to filter out the nil results of that
transforming function.
That sounds useful -- there's more than a 100 matches for "delq
nil.*map" in-tree only -- but it's slightly confusing that the function
isn't altogether a predicate, but only kinda. Would a function
signature like
(cl-defgeneric seq-keep (function sequence &optional pred)
...)
make more sense for this combination of map/filter? (The default
predicate would, of course, be "not null".)
next prev parent reply other threads:[~2022-10-03 23:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-03 21:30 bug#58278: Add new function seq-keep Jonas Bernoulli
2022-10-03 23:47 ` Lars Ingebrigtsen [this message]
2022-10-04 10:05 ` Robert Pluim
2022-10-04 10:13 ` Lars Ingebrigtsen
2022-10-04 10:27 ` Robert Pluim
2022-10-04 10:42 ` Lars Ingebrigtsen
2022-10-04 10:50 ` Robert Pluim
2022-10-04 11:10 ` Lars Ingebrigtsen
2022-10-04 11:21 ` Robert Pluim
2022-10-04 11:23 ` Lars Ingebrigtsen
2022-10-04 11:37 ` Robert Pluim
2022-10-04 12:50 ` Jonas Bernoulli
2022-10-04 13:47 ` Lars Ingebrigtsen
2022-10-04 13:56 ` Lars Ingebrigtsen
2022-10-04 13:59 ` Lars Ingebrigtsen
2022-10-04 19:46 ` Lars Ingebrigtsen
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