From: Drew Adams <drew.adams@oracle.com>
To: Emanuel Berg <embe8573@student.uu.se>, help-gnu-emacs@gnu.org
Subject: RE: member returns list (was: Re: To `boundp' or not to `boundp'?)
Date: Tue, 1 Sep 2015 17:10:56 -0700 (PDT) [thread overview]
Message-ID: <3c9412c3-3fff-446c-9e55-e8169b6a913d@default> (raw)
In-Reply-To: <87lhcpu2wb.fsf_-_@debian.uxu>
> Yes, and I have wondered about that. Is it useful,
> perhaps with the use of `car' (?) as in:
> (car (member 2 '(1 2 3))) ; 2
> (car (member 0 '(1 2 3))) ; nil
Yes, extremely useful.
> Or is it some "leftover optimization" thing where
> `cdr' is faster than returning `t', and can be used
> the same way? Or is it something else?
No and no.
It's an access function, like `assoc' or `elt'.
If no such member can be found then it returns nil,
which means that it can also function as a simple
membership test.
next prev parent reply other threads:[~2015-09-02 0:10 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-01 15:50 To `boundp' or not to `boundp'? Alexander Shukaev
2015-09-01 15:51 ` Dmitry Gutov
2015-09-01 15:53 ` Alexander Shukaev
2015-09-01 16:42 ` Drew Adams
2015-09-01 17:13 ` Michael Heerdegen
2015-09-01 18:00 ` Drew Adams
[not found] ` <mailman.331.1441125765.19560.help-gnu-emacs@gnu.org>
2015-09-01 20:20 ` Barry Margolin
2015-09-01 23:37 ` member returns list (was: Re: To `boundp' or not to `boundp'?) Emanuel Berg
2015-09-02 0:10 ` Drew Adams [this message]
2015-09-02 0:27 ` Emanuel Berg
2015-09-02 0:38 ` Drew Adams
2015-09-02 1:17 ` Emanuel Berg
2015-09-02 6:21 ` Drew Adams
2015-09-02 21:20 ` Emanuel Berg
[not found] ` <mailman.370.1441156160.19560.help-gnu-emacs@gnu.org>
2015-09-03 5:17 ` member returns list Pascal J. Bourguignon
2015-09-04 0:26 ` Emanuel Berg
2015-09-02 16:45 ` Michael Heerdegen
2015-09-02 21:47 ` Emanuel Berg
2015-09-02 22:09 ` Michael Heerdegen
2015-09-02 22:11 ` Drew Adams
2015-09-02 22:13 ` Marcin Borkowski
2015-09-04 1:03 ` Emanuel Berg
2015-09-04 6:50 ` Marcin Borkowski
2015-09-05 17:35 ` Emanuel Berg
2015-09-05 17:55 ` Random832
2015-09-05 18:09 ` Emanuel Berg
2015-09-05 21:04 ` Random832
2015-09-06 2:57 ` Emanuel Berg
[not found] ` <mailman.552.1441475739.19560.help-gnu-emacs@gnu.org>
2015-09-05 23:39 ` Pascal J. Bourguignon
2015-09-06 2:46 ` Emanuel Berg
2015-09-09 1:48 ` Robert Thorpe
2015-09-09 2:44 ` Pascal J. Bourguignon
2015-09-09 3:19 ` John Mastro
2015-09-10 0:25 ` Emanuel Berg
[not found] ` <mailman.557.1441507097.19560.help-gnu-emacs@gnu.org>
2015-09-06 21:20 ` Pascal J. Bourguignon
2015-09-06 23:33 ` Emanuel Berg
[not found] ` <mailman.598.1441581917.19560.help-gnu-emacs@gnu.org>
2015-09-06 23:47 ` Pascal J. Bourguignon
2015-09-07 1:29 ` Pascal J. Bourguignon
2015-09-07 2:25 ` Emanuel Berg
2015-09-09 1:44 ` Robert Thorpe
2015-09-10 0:23 ` Emanuel Berg
[not found] ` <mailman.793.1441844665.19560.help-gnu-emacs@gnu.org>
2015-09-10 2:01 ` Pascal J. Bourguignon
2015-09-10 2:32 ` Emanuel Berg
[not found] ` <ECCA0E56-A051-4D38-8CBB-6CE9208BB047@openmailbox.org>
2015-09-11 1:32 ` Emanuel Berg
2015-09-11 1:46 ` Emanuel Berg
[not found] ` <mailman.797.1441852386.19560.help-gnu-emacs@gnu.org>
2015-09-10 4:21 ` Pascal J. Bourguignon
2015-09-10 18:09 ` Alex Kost
2015-09-11 1:01 ` Random832
2015-09-11 1:28 ` Emanuel Berg
2015-09-11 2:01 ` Emanuel Berg
2015-09-11 2:52 ` Random832
[not found] ` <mailman.890.1441936900.19560.help-gnu-emacs@gnu.org>
2015-09-11 2:27 ` Pascal J. Bourguignon
2015-09-12 0:10 ` Emanuel Berg
2015-09-11 2:37 ` Ian Zimmerman
2015-09-11 1:03 ` Emanuel Berg
2015-09-11 0:57 ` Emanuel Berg
2015-09-11 5:42 ` tomas
2015-09-12 0:18 ` Emanuel Berg
2015-09-13 8:12 ` tomas
[not found] ` <mailman.897.1441950163.19560.help-gnu-emacs@gnu.org>
2015-09-11 23:29 ` Pascal J. Bourguignon
2015-09-12 0:20 ` Emanuel Berg
[not found] ` <mailman.966.1442016910.19560.help-gnu-emacs@gnu.org>
2015-09-12 2:01 ` Pascal J. Bourguignon
2015-09-12 3:26 ` Emanuel Berg
2015-09-13 7:50 ` tomas
2015-09-12 2:03 ` Pascal J. Bourguignon
2015-09-12 2:45 ` Stefan Monnier
2015-09-12 3:12 ` Emanuel Berg
2015-09-12 3:31 ` Emanuel Berg
[not found] ` <mailman.972.1442025961.19560.help-gnu-emacs@gnu.org>
2015-09-12 6:16 ` Pascal J. Bourguignon
2015-09-12 23:38 ` Emanuel Berg
2015-09-13 8:03 ` tomas
2015-09-14 1:31 ` Emanuel Berg
[not found] ` <mailman.1016.1442100597.19560.help-gnu-emacs@gnu.org>
2015-09-13 0:09 ` Pascal J. Bourguignon
2015-09-13 0:24 ` John Mastro
[not found] ` <mailman.1019.1442103883.19560.help-gnu-emacs@gnu.org>
2015-09-13 4:29 ` Pascal J. Bourguignon
2015-09-16 0:01 ` computer history (was: Re: member returns list) Emanuel Berg
[not found] ` <mailman.978.1442028310.19560.help-gnu-emacs@gnu.org>
2015-09-12 6:18 ` member returns list Pascal J. Bourguignon
2015-09-12 23:56 ` Emanuel Berg
[not found] ` <mailman.1018.1442101697.19560.help-gnu-emacs@gnu.org>
2015-09-13 0:20 ` Pascal J. Bourguignon
2015-09-14 1:24 ` Emanuel Berg
2015-09-12 2:04 ` Pascal J. Bourguignon
2015-09-12 3:15 ` Emanuel Berg
2015-09-12 7:40 ` Eli Zaretskii
[not found] ` <mailman.884.1441933051.19560.help-gnu-emacs@gnu.org>
2015-09-11 2:26 ` Pascal J. Bourguignon
2015-09-12 0:16 ` Emanuel Berg
2015-09-07 2:38 ` Drew Adams
2015-09-07 2:37 ` Drew Adams
[not found] ` <mailman.502.1441349470.19560.help-gnu-emacs@gnu.org>
2015-09-04 17:26 ` Barry Margolin
2015-09-05 17:40 ` Emanuel Berg
2015-09-02 0:40 ` member (was: Re: To `boundp' or not to `boundp'?) Emanuel Berg
[not found] ` <mailman.363.1441150201.19560.help-gnu-emacs@gnu.org>
2015-09-02 16:25 ` member returns list " Barry Margolin
2015-09-02 21:35 ` Emanuel Berg
[not found] ` <mailman.426.1441229773.19560.help-gnu-emacs@gnu.org>
2015-09-02 22:56 ` Barry Margolin
2015-09-02 23:23 ` Emanuel Berg
[not found] ` <mailman.368.1441153951.19560.help-gnu-emacs@gnu.org>
2015-09-03 5:19 ` member Pascal J. Bourguignon
2015-09-04 0:24 ` member Emanuel Berg
[not found] ` <<barmar-B5D67F.16201001092015@88-209-239-213.giganet.hu>
2015-09-01 20:42 ` To `boundp' or not to `boundp'? Drew Adams
2015-09-02 2:12 ` Stefan Monnier
2015-09-02 15:26 ` Alexander Shukaev
2015-09-02 16:51 ` Michael Heerdegen
[not found] ` <mailman.410.1441212753.19560.help-gnu-emacs@gnu.org>
2015-09-02 20:00 ` Barry Margolin
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