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From: "Basil L. Contovounesios" <contovob@tcd.ie>
To: dalanicolai <dalanicolai@gmail.com>
Cc: 47368@debbugs.gnu.org
Subject: bug#47368: 28.0.50; map-elt returns nil without "deprecated" TESTFN
Date: Wed, 24 Mar 2021 23:24:49 +0000	[thread overview]
Message-ID: <87sg4kyw1q.fsf@tcd.ie> (raw)
In-Reply-To: <CACJP=3k08VBaj-O5KzqJyDbbkSpsOKLMFHtS5tEJfuSU2Wkmqg@mail.gmail.com> (dalanicolai's message of "Wed, 24 Mar 2021 23:52:57 +0100")

dalanicolai <dalanicolai@gmail.com> writes:

> The docstring of the map-elt function from the map.el package (version
> 3.0) mentions that TESTFN is deprecated because "its default depends on
> the MAP argument". However when I try e.g.
>
> (map-elt '(("A1" . 3)) "A1")
>
> it returns nil.

This is expected, as alist keys are tested with eq by default.

That's what the docstring is trying to warn about: alists default to
testing with eq, but can also use eql, equal, or anything else.

Hash tables, OTOH, are limited to the test function that they were
created with.

So TESTFN doesn't always work as expected depending on the map type.

> When I add the correct TESTFN
>
> (map-elt '(("A1" . 3)) "A1" nil 'string=)
>
> it does correctly return 3.
>
> So it seems to me that TESTFN is not yet deprecated, or that otherwise I
> am understanding it incorrectly.

Deprecation means "this is not recommended" and "support for this may be
removed in a future version".

So to me TESTFN seems to be working as intended.

> In that case I would label this as a documentation bug.

What would you like to see clarified in the documentation?

Thanks,

-- 
Basil





  reply	other threads:[~2021-03-24 23:24 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-24 22:52 bug#47368: 28.0.50; map-elt returns nil without "deprecated" TESTFN dalanicolai
2021-03-24 23:24 ` Basil L. Contovounesios [this message]
2021-03-25  2:39   ` Michael Heerdegen
2021-03-25 14:48     ` dalanicolai
2021-03-25 15:33     ` bug#47368: [External] : " Drew Adams
2021-03-26 18:47       ` Basil L. Contovounesios
2021-03-26 20:04         ` Drew Adams
2021-03-26 20:23           ` Basil L. Contovounesios
2021-03-26 22:40             ` Drew Adams
2021-03-26 22:59               ` Basil L. Contovounesios
2021-03-26  3:59     ` Michael Heerdegen
2021-03-26  7:38       ` dalanicolai
2021-03-26 13:31       ` Stefan Monnier
2021-03-26 15:32         ` dalanicolai
2021-03-26 18:57         ` Basil L. Contovounesios
2021-03-26 23:18           ` Michael Heerdegen
2021-03-27 20:37           ` Basil L. Contovounesios
2021-03-26 23:23         ` Michael Heerdegen
2021-03-26 18:58     ` Basil L. Contovounesios
2021-07-21 15:34 ` Adam Porter
2021-07-22  2:15   ` Michael Heerdegen
2021-07-31  2:15     ` Michael Heerdegen
2021-09-13 14:06       ` Adam Porter
2021-09-14 14:40         ` Michael Heerdegen
2021-09-14 20:22           ` Basil L. Contovounesios via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-09-15  0:48             ` Michael Heerdegen
2021-09-15  9:26               ` Basil L. Contovounesios via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-09-15 12:39               ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-09-15 21:53                 ` Michael Heerdegen
2021-09-15 12:50             ` Basil L. Contovounesios via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-09-15 21:55               ` Michael Heerdegen
2021-09-21 12:42                 ` Basil L. Contovounesios via Bug reports for GNU Emacs, the Swiss army knife of text editors

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