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From: Konstantin Kharlamov <Hi-Angel@yandex.ru>
To: Eli Zaretskii <eliz@gnu.org>,
	Michael Heerdegen <michael_heerdegen@web.de>
Cc: 69108@debbugs.gnu.org
Subject: bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let
Date: Sat, 17 Feb 2024 12:20:16 +0300	[thread overview]
Message-ID: <78798be7b3bc7a7bb477d4ec952734b199588d00.camel@yandex.ru> (raw)
In-Reply-To: <86eddbv7no.fsf@gnu.org>

On Sat, 2024-02-17 at 10:04 +0200, Eli Zaretskii wrote:
> > Cc: 69108@debbugs.gnu.org
> > Date: Sat, 17 Feb 2024 01:28:55 +0100
> > From:  Michael Heerdegen via "Bug reports for GNU Emacs,
> >  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> > 
> > --- a/lisp/subr.el
> > +++ b/lisp/subr.el
> > @@ -2575,12 +2575,12 @@ delay-mode-hooks
> >  (defun internal--build-binding (binding prev-var)
> >    "Check and build a single BINDING with PREV-VAR."
> >    (setq binding
> > -        (cond
> > -         ((symbolp binding)
> > +        (pcase binding
> > +         ((pred symbolp)
> >            (list binding binding))
> > -         ((null (cdr binding))
> > -          (list (make-symbol "s") (car binding)))
> > -         (t binding)))
> > +         ((or `(,test) `(_ ,test))
> > +          (list (make-symbol "s") test))
> > +         (_ binding)))
> 
> Thanks, but can we please leave this as 'cond', instead of converting
> it to a 'pcase'?  It doesn't seem to be justified here, and even less
> so since you need to rewrite all the existing conditions.

Just a side note, from my experience pcase is very slow¹, so if a
function supposed to be called often, I presume it's better to avoid
`pcase`. Although, Idk how it compares to `cond`. But judging from the
fact `cond` is implemented in C, it is likely faster.

1:
https://github.com/ankurdave/color-identifiers-mode/commit/bc566bcdbd79f230b35eafd2b6c4f8428402ec09





  reply	other threads:[~2024-02-17  9:20 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-13 21:21 bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let Konstantin Kharlamov
2024-02-14  1:01 ` Michael Heerdegen via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-02-17  0:28   ` Michael Heerdegen via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-02-17  8:04     ` Eli Zaretskii
2024-02-17  9:20       ` Konstantin Kharlamov [this message]
2024-02-17 11:45         ` Ihor Radchenko
2024-02-17 10:09           ` Konstantin Kharlamov
2024-02-19 12:37             ` Ihor Radchenko
2024-02-19 13:44               ` Konstantin Kharlamov
2024-02-17 21:46         ` Michael Heerdegen via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-02-17 22:02       ` Michael Heerdegen via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-02-18  6:53         ` Eli Zaretskii
2024-02-25  1:54           ` Michael Heerdegen via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-02-25  7:42             ` Eli Zaretskii

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