From: Michael Heerdegen via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
To: Eli Zaretskii <eliz@gnu.org>
Cc: Hi-Angel@yandex.ru, 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 23:02:07 +0100 [thread overview]
Message-ID: <874je6agww.fsf@web.de> (raw)
In-Reply-To: <86eddbv7no.fsf@gnu.org> (Eli Zaretskii's message of "Sat, 17 Feb 2024 10:04:11 +0200")
Eli Zaretskii <eliz@gnu.org> writes:
> > 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.
Oh no.
If I don't rewrite this with `pcase', we would either artificially split
this case:
((or `(,test) `(_ ,test))
(list (make-symbol "s") test))
into two separate `cond' branches, or we had to merge them into a one branch
like this:
((or (null (cdr binding))
(eq '_ (car binding)))
(list (make-symbol "s")
(if (null (cdr binding))
(car binding)
(cadr binding))))
repeating a test. Is this what you prefer?
We could also move the test for _ to the beginning, destroying the logic
of the code. All of those alternatives seems worse wrt readability.
Please to everyone: let's avoid a new discussion about `pcase'. Please,
not again.
> > [My doc tweaks]
> This hunk seems to be unrelated?
Yes, I can make it a separate commit it drop it entirely if you prefer.
> And it is not necessarily for the better, IMO, at least not all of it
> (replaces active tense with passive, refills text that doesn't need
> refilling, and other minor issues,
I can try to improve that of course.
> like the confusing use of construct state in "last ELSE form").
Dunno what a "construct state" is. The doc missed to tell what `if-let'
returns when optional ELSE forms are omitted (which is allowed, and then
there is no last ELSE form return value), so I tried to add that. Did I
mess up the grammar?
Michael.
next prev parent reply other threads:[~2024-02-17 22:02 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=874je6agww.fsf@web.de \
--to=bug-gnu-emacs@gnu.org \
--cc=69108@debbugs.gnu.org \
--cc=Hi-Angel@yandex.ru \
--cc=eliz@gnu.org \
--cc=michael_heerdegen@web.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).