GNU bug report logs - #36035
26.2; doc string of `add-to-list'

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Drew Adams <drew.adams <at> oracle.com>
To: bug-gnu-emacs <at> gnu.org
Subject: 26.2; doc string of `add-to-list'
Date: Fri, 31 May 2019 13:46:16 -0700 (PDT)

The doc in (elisp) `List Variables' is OK.  The doc string is not.

The doc string says this:

  Add ELEMENT to the value of LIST-VAR if it isn't there yet.

That doesn't say what it does it ELEMENT _is_ already there (and it
should).

But one might easily get the impression that it does NOT add ELEMENT if
it is already present.  And that's just plain wrong.

(setq foo '((a . "aaa") (b . "bbb"))) ; => ((a . "aaa") (b . "bbb"))

(add-to-list 'foo '(a . "@@@@")) ; => ((a . "@@@@") (a . "aaa") (b . "bbb"))

In GNU Emacs 26.2 (build 1, x86_64-w64-mingw32)
 of 2019-04-13
Repository revision: fd1b34bfba8f3f6298df47c8e10b61530426f749
Windowing system distributor `Microsoft Corp.', version 10.0.17134
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''

Message #8 received at 36035 <at> debbugs.gnu.org (full text, mbox):

From: npostavs <at> gmail.com
To: Drew Adams <drew.adams <at> oracle.com>
Cc: 36035 <at> debbugs.gnu.org
Subject: Re: bug#36035: 26.2; doc string of `add-to-list'
Date: Fri, 31 May 2019 16:51:02 -0400

Drew Adams <drew.adams <at> oracle.com> writes:

> But one might easily get the impression that it does NOT add ELEMENT if
> it is already present.  And that's just plain wrong.
>
> (setq foo '((a . "aaa") (b . "bbb"))) ; => ((a . "aaa") (b . "bbb"))
>
> (add-to-list 'foo '(a . "@@@@")) ; => ((a . "@@@@") (a . "aaa") (b . "bbb"))

Have you mixed up add-to-list with some hypothetical add-to-alist?

(setq foo '((a . "aaa") (b . "bbb"))) ; => ((a . "aaa") (b . "bbb"))

(add-to-list 'foo '(a . "aaa")) ; => ((a . "aaa") (b . "bbb"))

Message #11 received at 36035 <at> debbugs.gnu.org (full text, mbox):

From: Drew Adams <drew.adams <at> oracle.com>
To: npostavs <at> gmail.com
Cc: 36035 <at> debbugs.gnu.org
Subject: RE: bug#36035: 26.2; doc string of `add-to-list'
Date: Fri, 31 May 2019 14:02:38 -0700 (PDT)

> Have you mixed up add-to-list with some hypothetical add-to-alist?
> 
> (setq foo '((a . "aaa") (b . "bbb"))) ; => ((a . "aaa") (b . "bbb"))
> (add-to-list 'foo '(a . "aaa")) ; => ((a . "aaa") (b . "bbb"))

Duh. ;-)  Need more coffee, for sure.
Sorry about that.  I'll close it.

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