From: Michael Heerdegen via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
To: Konstantin Kharlamov <Hi-Angel@yandex.ru>
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 01:28:55 +0100 [thread overview]
Message-ID: <87mss09bnc.fsf@web.de> (raw)
In-Reply-To: <87il2ryi30.fsf@web.de> (Michael Heerdegen's message of "Wed, 14 Feb 2024 02:01:39 +0100")
[-- Attachment #1: Type: text/plain, Size: 109 bytes --]
I <michael_heerdegen@web.de> write:
> Would be a one liner to make both cases generate the same expansion.
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-Don-t-warn-about-_-not-left-unused-in-if-let-and-ali.patch --]
[-- Type: text/x-diff, Size: 3024 bytes --]
From 906355a716864c87aa0ea112ac890ec9f59d0089 Mon Sep 17 00:00:00 2001
From: Michael Heerdegen <michael_heerdegen@web.de>
Date: Fri, 16 Feb 2024 22:07:18 +0100
Subject: [PATCH] Don't warn about _ not left unused in if-let and alike
Fix Bug#69108: The macro expansions did not leave a variable _ unused;
this triggered a compiler warning.
* lisp/subr.el (internal--build-binding): Handle (_ FORM) separately.
(if-let, and-let*): Tweak doc.
---
lisp/subr.el | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/lisp/subr.el b/lisp/subr.el
index c317d558e24..4f22f0c6b3f 100644
--- 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)))
(when (> (length binding) 2)
(signal 'error
(cons "`let' bindings can have only one value-form" binding)))
@@ -2620,7 +2620,7 @@ when-let*
(defmacro and-let* (varlist &rest body)
"Bind variables according to VARLIST and conditionally evaluate BODY.
Like `when-let*', except if BODY is empty and all the bindings
-are non-nil, then the result is non-nil."
+are non-nil, then the result is the value of the last binding."
(declare (indent 1) (debug if-let*))
(let (res)
(if varlist
@@ -2631,9 +2631,9 @@ and-let*
(defmacro if-let (spec then &rest else)
"Bind variables according to SPEC and evaluate THEN or ELSE.
-Evaluate each binding in turn, as in `let*', stopping if a
-binding value is nil. If all are non-nil return the value of
-THEN, otherwise the last form in ELSE.
+Evaluate each binding in turn, as in `let*', stopping if a binding value
+is nil. If all are non-nil return the value of THEN, otherwise the
+value of the last ELSE form or nil if there are none.
Each element of SPEC is a list (SYMBOL VALUEFORM) that binds
SYMBOL to the value of VALUEFORM. An element can additionally be
@@ -2642,9 +2642,9 @@ if-let
interest. It can also be of the form SYMBOL, then the binding of
SYMBOL is checked for nil.
-As a special case, interprets a SPEC of the form \(SYMBOL SOMETHING)
-like \((SYMBOL SOMETHING)). This exists for backward compatibility
-with an old syntax that accepted only one binding."
+As a special case that exists for backward compatibility only, a
+complete SPEC of the form \(SYMBOL SOMETHING) is interpreted like
+\((SYMBOL SOMETHING))."
(declare (indent 2)
(debug ([&or (symbolp form) ; must be first, Bug#48489
(&rest [&or symbolp (symbolp form) (form)])]
--
2.39.2
[-- Attachment #3: Type: text/plain, Size: 11 bytes --]
Michael.
next prev parent reply other threads:[~2024-02-17 0:28 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 [this message]
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
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
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87mss09bnc.fsf@web.de \
--to=bug-gnu-emacs@gnu.org \
--cc=69108@debbugs.gnu.org \
--cc=Hi-Angel@yandex.ru \
--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 external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.