From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Michael Heerdegen Newsgroups: gmane.emacs.help Subject: Re: [External] : Closures - do you understand them well? Date: Thu, 08 Dec 2022 19:49:20 +0100 Message-ID: <87mt7xpw7j.fsf@web.de> References: <87lenh7vrn.fsf@web.de> <87cz8t7qh5.fsf@web.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="31910"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:KWAaI8p8+m3Aq8YafDG1Tg1OYBg= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Thu Dec 08 19:50:17 2022 Return-path: Envelope-to: geh-help-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 1p3LyJ-000859-U9 for geh-help-gnu-emacs@m.gmane-mx.org; Thu, 08 Dec 2022 19:50:15 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p3Lxn-0000GJ-JH; Thu, 08 Dec 2022 13:49:43 -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 1p3Lxh-0000Fl-6i for help-gnu-emacs@gnu.org; Thu, 08 Dec 2022 13:49:37 -0500 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p3Lxf-00085q-O1 for help-gnu-emacs@gnu.org; Thu, 08 Dec 2022 13:49:36 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1p3LxX-0006y0-Km for help-gnu-emacs@gnu.org; Thu, 08 Dec 2022 19:49:27 +0100 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -13 X-Spam_score: -1.4 X-Spam_bar: - X-Spam_report: (-1.4 / 5.0 requ) BAYES_00=-1.9, FREEMAIL_FORGED_FROMDOMAIN=0.229, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:141465 Archived-At: Drew Adams writes: > You say, "which accidentally happens to be > the same again in Lisp". To me it's not an > accident; it's by design. Sure it's by design, and it's convenient. But for readability purposes that doesn't matter that much. When the reader encounters "()" I expect it to construct an empty list. That's what I want, so I quote it to get exactly that when that expression is evaluated. If we do not limit ourselves to Emacs Lisp, the (not trivial) question would else be: what is the return value when evaluating an empty list? Not trivial because there can be Lisps where an empty list and a boolean "false" are different (AFAIR such Lisps exist). So the result of evaluating an empty list could be: - an empty list/ the same empty list (self-evaluating) - undefined - a Boolean value false - ...maybe something else? Because I don't want to tangent this question I prefer to quote the empty list. What are your reasons to prefer to evaluate it and use the result? Michael.