From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg via Users list for the GNU Emacs text editor Newsgroups: gmane.emacs.help Subject: Re: Appending lists Date: Wed, 16 Jun 2021 18:54:18 +0200 Message-ID: <87im2dvjgl.fsf@zoho.eu> References: <4tl1yvylvg1fxx5eefjs9mnk.1623688568572@email.android.com> <87o8c8l32h.fsf@posteo.net> <87zgvs2bup.fsf@zoho.eu> <87y2bby1kr.fsf@zoho.eu> <20210615091834.GB24886@tuxteam.de> <87im2ewr3k.fsf@zoho.eu> <20210616072819.GB17919@tuxteam.de> Reply-To: Emanuel Berg Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="24144"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:kFj7vMY7Cyoxz1PQNF7ClAlM+qc= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Wed Jun 16 18:58:18 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 1ltYrq-00068i-8t for geh-help-gnu-emacs@m.gmane-mx.org; Wed, 16 Jun 2021 18:58:18 +0200 Original-Received: from localhost ([::1]:41868 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ltYro-0006Xn-Be for geh-help-gnu-emacs@m.gmane-mx.org; Wed, 16 Jun 2021 12:58:16 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:44632) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ltYoA-0003Gb-GO for help-gnu-emacs@gnu.org; Wed, 16 Jun 2021 12:54:31 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:60366) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ltYo8-000642-VT for help-gnu-emacs@gnu.org; Wed, 16 Jun 2021 12:54:30 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1ltYo7-00015t-CY for help-gnu-emacs@gnu.org; Wed, 16 Jun 2021 18:54:27 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Mail-Copies-To: never 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: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, 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: 2.1.23 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:130911 Archived-At: Jean Louis wrote: > You said vairable did not change, maybe it did not change > somewhere underground This is how I understand it: The variable has a reference to the first cons cell of the list. The cons cell has a car and a cdr as always, where the cdr is a reference to the second element of the list, which is also a cons cell, and so on. The car of the first element's cons cell remains the same but the cdr has changed as a side-effect of `nreverse' (or `nconc'). So when the variable seemingly holding the list, but actually only holding a reference to the first cons cell, when this variable is used one will have a different list as a result even tho the reference is the same, unchanged. tomas, is this correct? Maybe I won't have to draw the diagram after all... :) -- underground experts united https://dataswamp.org/~incal