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 18:30:30 +0100 Message-ID: <87cz8t7qh5.fsf@web.de> References: <87lenh7vrn.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="34787"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:EAxzIX/k6q50u2uhcDTz0oMdbxI= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Thu Dec 08 18:31:09 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 1p3Kjk-0008rT-RO for geh-help-gnu-emacs@m.gmane-mx.org; Thu, 08 Dec 2022 18:31:08 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p3KjM-0006JP-Ac; Thu, 08 Dec 2022 12:30:44 -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 1p3KjK-0006Iv-7R for help-gnu-emacs@gnu.org; Thu, 08 Dec 2022 12:30:42 -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 1p3KjI-0001im-AI for help-gnu-emacs@gnu.org; Thu, 08 Dec 2022 12:30:41 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1p3KjF-0008Mc-C2 for help-gnu-emacs@gnu.org; Thu, 08 Dec 2022 18:30:37 +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:141462 Archived-At: Drew Adams writes: > Just a mention for others, that '() == (). > No need to quote t or nil (including its > alter ego ()). You are lucky that your remark doesn't fulfill the "you better write this as ... and then it returns ..." answer property because it doesn't change the return value ;-) But yes, like explicitly specifying a nil binding (X nil) instead of (X) this is bout readability and personal preferences. (X '()) is my hint to the reader that X will be used as a list type accumulator in the BODY. I prefer that over (X ()), (X nil) and (X). It's a stylistic habit. Why? Because I want to make clear that the variable is initialized with an empty list, compared to what the evaluation of an empty list aka nil returns (which accidentally happens to be the same again in Lisp). Thanks for mentioning this point Drew, Michael.