From: "Miguel V. S. Frasson" <mvsfrasson@gmail.com>
To: Michael Heerdegen <michael_heerdegen@web.de>
Cc: 34708@debbugs.gnu.org
Subject: bug#34708: alist-get has unclear documentation
Date: Sun, 3 Mar 2019 08:32:45 -0300 [thread overview]
Message-ID: <CAARdmY3tS0poY8nE1p3ysCazbbcWgxxLVmwGi+aATQ7JZmFKAg@mail.gmail.com> (raw)
In-Reply-To: <87y35xdu4w.fsf@web.de>
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Hi
I think the sentence below is a good and short explanation for the
doc-string.
The return value can be conveniently used as a generalized variable (a
place) to set the value associated with KEY in ALIST, like in the example
(setf (alist-get key alist) new-value)
Miguel
Em sáb, 2 de mar de 2019 15:10, Michael Heerdegen <michael_heerdegen@web.de>
escreveu:
> "Miguel V. S. Frasson" <mvsfrasson@gmail.com> writes:
>
> > I can't imagine how to *set* anything with alist-get. It seams to me
> > that it just use the value of ALIST for look up, so talk about
> > generalized variables is meaningless to me here.
>
> You use it like this: say variable V is bound to an alist, then you can
> do (setf (alist-get key V) value). After that, (alist-get key V) will
> evaluate to VALUE, so you have "set" that place. In the general case, V
> can also be a generalized variable, e.g. (car SOMETHING-ELSE).
>
> To replace the word "this" with something better is not so easy. We
> could write "The name of this function can be used to build expressions
> that can be used as a generalized variable", but I doubt it will make
> things clearer for somebody not familiar with the concept of generalized
> variables. Using this function name to build place expressions is not
> different from using other function names that allow to be used for
> generalized variables.
>
> I would rather go with an example, which I think is justified because
> using this function name in place expressions is the canonical way to
> modify alists and people need to use it (there is no `alist-put') no
> matter if they are familiar with generalized variables.
>
> Michael.
>
>
>
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next prev parent reply other threads:[~2019-03-03 11:32 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-02 4:50 bug#34708: alist-get has unclear documentation Miguel V. S. Frasson
2019-03-02 9:25 ` Michael Heerdegen
2019-03-02 15:40 ` Miguel V. S. Frasson
2019-03-02 18:10 ` Michael Heerdegen
2019-03-02 19:06 ` Eric Abrahamsen
2019-03-03 0:15 ` Phil Sainty
2019-03-03 12:50 ` Michael Heerdegen
2019-03-19 1:35 ` Michael Heerdegen
2019-03-02 19:51 ` Miguel V. S. Frasson
2019-03-02 20:32 ` Eric Abrahamsen
2019-03-03 11:32 ` Miguel V. S. Frasson [this message]
2019-03-03 12:21 ` Michael Heerdegen
2019-03-03 15:51 ` Drew Adams
2019-03-03 16:49 ` Eric Abrahamsen
2019-03-04 16:24 ` Eric Abrahamsen
2019-03-04 16:38 ` Michael Heerdegen
2019-03-04 17:16 ` Eric Abrahamsen
2019-03-04 18:22 ` Michael Heerdegen
2019-03-04 22:49 ` Eric Abrahamsen
2019-03-05 12:35 ` Michael Heerdegen
2019-03-05 22:50 ` Eric Abrahamsen
2019-03-06 0:16 ` Drew Adams
2019-03-11 13:39 ` Michael Heerdegen
2019-03-11 14:52 ` Drew Adams
2019-03-11 16:19 ` Michael Heerdegen
2019-03-11 17:48 ` Drew Adams
2019-03-12 13:04 ` Michael Heerdegen
2019-03-12 14:48 ` Drew Adams
2019-03-12 16:08 ` Michael Heerdegen
2019-03-12 16:48 ` Drew Adams
2019-03-12 17:45 ` Michael Heerdegen
2019-03-12 13:12 ` Michael Heerdegen
2019-03-12 14:53 ` Drew Adams
2019-03-12 15:38 ` Michael Heerdegen
2019-03-12 16:18 ` Drew Adams
2019-03-12 17:55 ` Michael Heerdegen
2019-03-15 15:54 ` Michael Heerdegen
2019-03-15 18:48 ` Eric Abrahamsen
2019-03-27 22:31 ` Michael Heerdegen
2019-04-19 1:33 ` Michael Heerdegen
2019-04-19 2:24 ` bug#34708: Thanks Miguel V. S. Frasson
2019-04-19 4:18 ` Michael Heerdegen
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