From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Philip Kaludercic Newsgroups: gmane.emacs.bugs Subject: bug#71503: 30.0.50; pcase-lambda (with "and" and "guard") does not work as expected Date: Fri, 14 Jun 2024 08:42:25 +0000 Message-ID: <87h6dvud8u.fsf@posteo.net> References: <87r0d2lfjd.fsf@posteo.de> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="32569"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 71503@debbugs.gnu.org To: Mekeor Melire Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Fri Jun 14 10:43:17 2024 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1sI2Wj-0008Ja-MS for geb-bug-gnu-emacs@m.gmane-mx.org; Fri, 14 Jun 2024 10:43:17 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sI2WX-0001XI-6f; Fri, 14 Jun 2024 04:43:05 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sI2WU-0001Tb-Tm for bug-gnu-emacs@gnu.org; Fri, 14 Jun 2024 04:43:03 -0400 Original-Received: from debbugs.gnu.org ([2001:470:142:5::43]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1sI2WU-0006ZV-MK for bug-gnu-emacs@gnu.org; Fri, 14 Jun 2024 04:43:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1sI2WU-0003jq-Ek for bug-gnu-emacs@gnu.org; Fri, 14 Jun 2024 04:43:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Philip Kaludercic Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Fri, 14 Jun 2024 08:43:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 71503 X-GNU-PR-Package: emacs Original-Received: via spool by 71503-submit@debbugs.gnu.org id=B71503.171835455714334 (code B ref 71503); Fri, 14 Jun 2024 08:43:02 +0000 Original-Received: (at 71503) by debbugs.gnu.org; 14 Jun 2024 08:42:37 +0000 Original-Received: from localhost ([127.0.0.1]:39903 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1sI2W5-0003j8-8r for submit@debbugs.gnu.org; Fri, 14 Jun 2024 04:42:37 -0400 Original-Received: from mout02.posteo.de ([185.67.36.66]:56037) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1sI2W1-0003is-Bz for 71503@debbugs.gnu.org; Fri, 14 Jun 2024 04:42:35 -0400 Original-Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 1E87A240104 for <71503@debbugs.gnu.org>; Fri, 14 Jun 2024 10:42:26 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1718354547; bh=0+fBUuPqMbugK6MqULc2J3dIzsoys3+Zi+7ltTaNuNA=; h=From:To:Cc:Subject:OpenPGP:Date:Message-ID:MIME-Version: Content-Type:From; b=q1AWFNmV7tGwsi+5Ls+hIeG08aAInFOt2W9afH0jPQR1r3Qz1tZTXHQOL5Qa77i29 EIVowGTWIHZ6IzVOh9LdskCQiMWblzSBMz5ps4ZX+c3Cq+shsIf5pEETb7CmhPnHyn /qpLJ1JtbDQEQeTlVqnolRFuneLZ1dhEejeve2BkGaYCmzwKD0PAkzvtSCqBC21Ecz Qrox8k7oP6JZngAbXDi2GMR4UkTNruHQo/gXoQ/su8W3hzSqTBJZjQq1UUuE8AlWBY Gh3aumrt65LQOVICnwXk/Z/eG/5nvIFrKjzom5m8ZFqfp8QAtF7iM5KKa13oMnh3n2 93W6qYFV8aDlg== Original-Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4W0t7k16bDz9rxL; Fri, 14 Jun 2024 10:42:26 +0200 (CEST) In-Reply-To: <87r0d2lfjd.fsf@posteo.de> (Mekeor Melire's message of "Wed, 12 Jun 2024 08:40:54 +0000") OpenPGP: id=7126E1DE2F0CE35C770BED01F2C3CC513DB89F66; url="https://keys.openpgp.org/vks/v1/by-fingerprint/7126E1DE2F0CE35C770BED01F2C3CC513DB89F66"; preference=signencrypt X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.bugs:287219 Archived-At: Mekeor Melire writes: > I was expecting these two expressions to evaluate to the same value. > First, we call `pcase' on a value with a pattern involving `and' and > `guard': > > (pcase "value" > ((and v (guard (string= "not-value" v))) v)) > ;; => nil > > Second, let's use the same value and pattern, but this time using > `pcase-lambda': > > (funcall > (pcase-lambda > ((and v (guard (string= "not-value" v)))) v) > "value") > ;; => "value" > > Am I missing something or is this a bug? The difference is that pcase-lambda doesn't do case-distinction, but just pattern matching/destruncting. So if the pattern-matching fails, then the variable is just not bound, instead of the entire expression falling back to returning no value/nil. I am guessing you wanted to have something like Scheme's `case-lambda'[0]? Or we could clarify this point in the docstring. > In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version > 3.24.41, cairo version 1.16.0). [0] https://index.scheme.org/filterset/r7rs_small/%28scheme%2520case-lambda%29/case-lambda -- Philip Kaludercic on peregrine