From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Code for cond* Date: Mon, 12 Feb 2024 19:48:55 -0500 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="7921"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Cc: emacs-devel@gnu.org To: Richard Stallman Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Feb 13 01:49:54 2024 Return-path: Envelope-to: ged-emacs-devel@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 1rZgzh-0001l2-Lx for ged-emacs-devel@m.gmane-mx.org; Tue, 13 Feb 2024 01:49:53 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rZgyt-0005HM-Nq; Mon, 12 Feb 2024 19:49:03 -0500 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 1rZgys-0005Gn-CR for emacs-devel@gnu.org; Mon, 12 Feb 2024 19:49:02 -0500 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rZgyq-0001CT-DB; Mon, 12 Feb 2024 19:49:02 -0500 Original-Received: from pmg3.iro.umontreal.ca (localhost [127.0.0.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id 38A33442DD1; Mon, 12 Feb 2024 19:48:58 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1707785336; bh=DpuYhmogHEjMwHT/dDTU4Qun6h236hnPlKqlBjHXMEo=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=KY/sdaORLY67INZHRXco5iScrmnybPCaZ29fhRbZ6bfn8e0j0bAzEybGEFDVIJAQP 3d6Yzj57dXMldwSt6t6uBOXTWvse0RC9KYFIF1BsDw/AqOKkFS8r9wWu7GmgNYFH7E olP9Bi/BqGpC3+BOjOFbVac0ts86rQm6py1FXPmtrxPfMiXqPEtSNV/48JVblm39Ir TzDBEyl2LF4O+webg5GwZzmGtUG3PgIdEDl05jUHoxZdJMH9XYUO0nZQs06g5Vq7R6 eBoaP8V6yaz2SKeEQKyjlJJZyK5q72QtJK6SG7S2ZmyaSYGg86p8xu/a+SxxbC5ZBA Hbvc32WGrw4Zg== Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id E3A63442DB8; Mon, 12 Feb 2024 19:48:56 -0500 (EST) Original-Received: from pastel (unknown [104.247.238.113]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id BCC95120CC2; Mon, 12 Feb 2024 19:48:56 -0500 (EST) In-Reply-To: (Richard Stallman's message of "Sat, 03 Feb 2024 23:46:29 -0500") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:316155 Archived-At: > > Admittedly, for `cdr-ignore` it would take more than a one-liner, > > because it affects the interpretation of all the patterns within it > > (which makes its meaning somewhat unclear: should `(constrain x (null > > (cdr x)))` be ignored if it appears within a `cdr-ignore`?). > It affects only the built-in patterns that destructure cons cells > and lists That still doesn't clarify its meaning. E.g. I understand that `(head ,b) should match (head 1 2), but what about matching a value like (head) ? The code I have found so far makes it not match (head). How should this be documented? Why was this chosen? The main use-case I can think of for `cdr-ignore` is when matching against things like Lisp code, where a pattern like `(lambda ,args . ,body) should also match (lambda) because (lambda) is a (broken) lambda expression rather than being something *else* than a lambda expression. So I'm not sure the behavior you chose for `cdr-ignore` is the one we want. Stefan