From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Jean Louis Newsgroups: gmane.emacs.help Subject: Re: append, push, and add-to-list. Date: Sun, 4 Jul 2021 14:28:24 +0300 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="29155"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mutt/2.0.7+183 (3d24855) (2021-05-28) Cc: help-gnu-emacs To: Hongyi Zhao Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sun Jul 04 13:32:25 2021 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 1m00MK-0007Tn-SP for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 04 Jul 2021 13:32:24 +0200 Original-Received: from localhost ([::1]:55442 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m00MJ-0007rZ-PF for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 04 Jul 2021 07:32:23 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:47246) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m00M0-0007rN-N9 for help-gnu-emacs@gnu.org; Sun, 04 Jul 2021 07:32:04 -0400 Original-Received: from stw1.rcdrun.com ([217.170.207.13]:59811) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m00Lz-0004A8-1g for help-gnu-emacs@gnu.org; Sun, 04 Jul 2021 07:32:04 -0400 Original-Received: from localhost ([::ffff:197.157.34.164]) (AUTH: PLAIN admin, TLS: TLS1.3,256bits,ECDHE_RSA_AES_256_GCM_SHA384) by stw1.rcdrun.com with ESMTPSA id 0000000000057EA3.0000000060E19C2E.00006A7F; Sun, 04 Jul 2021 04:31:58 -0700 Mail-Followup-To: Hongyi Zhao , help-gnu-emacs Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=217.170.207.13; envelope-from=bugs@gnu.support; helo=stw1.rcdrun.com X-Spam_score_int: 1 X-Spam_score: 0.1 X-Spam_bar: / X-Spam_report: (0.1 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, URI_DOTEDU=1.999 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 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" Xref: news.gmane.io gmane.emacs.help:131451 Archived-At: * Hongyi Zhao [2021-07-04 08:12]: > Thank you. I listed the usages below for all above-mentioned functions > by {C-h f} function-name: > > (add-to-list LIST-VAR ELEMENT &optional APPEND COMPARE-FN) > (push NEWELT PLACE) > (cl-pushnew X PLACE [KEYWORD VALUE]...) > (append &rest SEQUENCES) Good, I can also see some possible inconsistencies with X and NEWELT, as it would be better to call X also NEWELT. I can also see that documentation for `cl-pushnew' is not adequate enough. You are probably expected to learn definition from Common Lisp to understand the KEYWORDs: http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/HyperSpec/Body/mac_pushnew.html#pushnew Function `append' will work with various sequences not just lists. Please see manual: (info "(elisp) Sequences Arrays Vectors") > > Because you use it more for configurations, then add-to-list would be: > > > > (add-to-list 'company-backends '(company-capf company-ispell)) > > Why can't this be written as follows, just like the other two? > > (add-to-list company-backends '(company-capf company-ispell)) > > > > > and with append > > > > (append company-backends '(company-capf company-ispell)) Functions `add-to-list' and `append' do different things, though similar. -- Jean Take action in Free Software Foundation campaigns: https://www.fsf.org/campaigns In support of Richard M. Stallman https://stallmansupport.org/