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bug#69108: false-positive warning "variable ‘_’ not left unused" in if-l
From: |
Michael Heerdegen |
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 |
User-agent: |
Gnus/5.13 (Gnus v5.13) |
I <michael_heerdegen@web.de> write:
> Would be a one liner to make both cases generate the same expansion.
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
Michael.
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Konstantin Kharlamov, 2024/02/13
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Michael Heerdegen, 2024/02/13
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let,
Michael Heerdegen <=
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Eli Zaretskii, 2024/02/17
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Konstantin Kharlamov, 2024/02/17
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Ihor Radchenko, 2024/02/17
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Konstantin Kharlamov, 2024/02/17
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Ihor Radchenko, 2024/02/19
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Konstantin Kharlamov, 2024/02/19
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Michael Heerdegen, 2024/02/17
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Michael Heerdegen, 2024/02/17
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Eli Zaretskii, 2024/02/18
- bug#69108: false-positive warning "variable ‘_’ not left unused" in if-let* and if-let, Michael Heerdegen, 2024/02/24