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: Fri, 23 Feb 2024 08:39:00 -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="3506"; 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 Fri Feb 23 14:43:20 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 1rdVpf-0000jv-D0 for ged-emacs-devel@m.gmane-mx.org; Fri, 23 Feb 2024 14:43:19 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rdVoo-00057j-8T; Fri, 23 Feb 2024 08:42:26 -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 1rdVld-0002ST-At for emacs-devel@gnu.org; Fri, 23 Feb 2024 08:39:09 -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 1rdVlb-00073W-CL; Fri, 23 Feb 2024 08:39:09 -0500 Original-Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 6983E80A6A; Fri, 23 Feb 2024 08:39:02 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1708695541; bh=ur1LKeG6V90yUI4czakGrwj1I21/ps6m4p7ljULDc6A=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=S0GT8RvpNCvw2m0rg4Moh9xZzDzT6NaqresDgmKdwZd/H+SUDtacdLb73xabhcSNP cxb0zj6cdtS6iCc7FQnYkpbN626UYWWHn9mRo/wHnoyDtyuvez4Vy9jgJD0Q/Aj3qN JGI3P2/cvhsckV7EppbCPYgNIAttPbf398MR2U+k3ortZEkHiBtjDdDsh3Sn9iBftH HTbimyFfBlsZ3xhGW7mgfp4V9vN41dee1brW9Q6UHrSqn4OjhpTrwXMx0STWQYyxn+ 1hGqB83rPpaLBNwTdSTd1a4c9havCqoJthFe82MWAPhs1RFBdtnjt3lQiCt9n1y+FX r+zVzYRcN/Enw== Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 4CB9E8090D; Fri, 23 Feb 2024 08:39:01 -0500 (EST) Original-Received: from pastel (unknown [45.72.205.238]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 2B61112016C; Fri, 23 Feb 2024 08:39:01 -0500 (EST) In-Reply-To: (Richard Stallman's message of "Thu, 22 Feb 2024 22:04:22 -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:316466 Archived-At: > > Your syntax (FUN VAR ARGS...) has two disadvantages in my view: > > - It fixes the argument to be checked as the first argument. > > - It does not syntactically distinguish the VAR from the normal > > arguments, making a bit too magical for my taste. > I think this is not a real disadvantage. What makes you think so? I doubt you'd consider coders' confusion as a feature, so what makes you think people won't find it confusing (and/or get confused, even when they may not realize it's confusing)? > The more general kind of constrained variable, with `constrain', does > not have those two limitations. Agreed. `constrain` is fine by me (I'd prefer a shorter word, but for the sake of avoiding bikeshedding, I'm fine with it). > The special nature of the first argument is something that users > will get used to as they see many instances of cond*. That could turn into "it's a pain they'll learn to live with". The question is whether introducing the risk of such problems is worth the expected upside. I suggest you grep for `(and.*(pred` to see which existing uses of Pcase's `pred` could take advantage of that shorthand, so we have a better idea of what's the expected upside. > > Of course, there remains the question whether this usage should be > > the one that gets the privilege of not needing a dedicated > > "keyword", i.e. to allowing using it without the surrounding > > `pred`: > > (FUN ,VAR ARGS...) > > If this syntax is easy to implement and doesn't cause difficulties, I'll > go along with it if people prefer it. That doesn't answer the important part of my question: Of course, there remains the question whether this usage should be the one that gets the privilege of not needing a dedicated "keyword", i.e. to allowing using it without the surrounding `pred`. -- Stefan