GNU bug report logs - #16567
24.3.50; pcase should signal an error if no case matches

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Package: emacs;

Reported by: Helmut Eller <eller.helmut <at> gmail.com>

Date: Mon, 27 Jan 2014 09:24:01 UTC

Severity: wishlist

Found in version 24.3.50

Fixed in version 25.1

Done: Leo Liu <sdl.web <at> gmail.com>

Bug is archived. No further changes may be made.

Full log

Message #20 received at 16567 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
To: Helmut Eller <eller.helmut <at> gmail.com>
Cc: 16567 <at> debbugs.gnu.org
Subject: Re: bug#16567: 24.3.50;
 pcase should signal an error if no case matches
Date: Mon, 08 Sep 2014 15:19:06 -0400

> pcase returns nil for this example:
>  (pcase 3
>    (1 1)
>    (2 2))
> it would be more useful if it would signal an error instead.  Manually
> adding a "catch-all case" and inventing some error message is tedious
> and it's also easy to forget.

The "nil default" is also very handy at times and pcase has been in use
for long enough that we can't really change this easily.

But we could add a new pcase-exhaustive macro that does that.


        Stefan
This bug report was last modified 10 years and 289 days ago.

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