From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: Easy to add with push but not to the end of a list Date: Tue, 06 Dec 2022 03:40:02 +0100 Message-ID: <871qpdgsql.fsf@dataswamp.org> References: <877czcid1d.fsf@web.de> <87a648kzov.fsf@dataswamp.org> <87cz93noqc.fsf@web.de> <87zgc76npf.fsf@dataswamp.org> <87k038npls.fsf@web.de> <87sfht8luq.fsf@dataswamp.org> <87h6y91ffg.fsf@web.de> <878rjlgvdd.fsf@dataswamp.org> <87bkoh1dix.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="29274"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:45uuXu39o9c/2/Pvh0I0LQMeZv4= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Tue Dec 06 07:43:15 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 1p2Rff-0007R6-99 for geh-help-gnu-emacs@m.gmane-mx.org; Tue, 06 Dec 2022 07:43:15 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p2Rf2-0001uA-IM; Tue, 06 Dec 2022 01:42:36 -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 1p2NsZ-0006VF-93 for help-gnu-emacs@gnu.org; Mon, 05 Dec 2022 21:40:19 -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 1p2NsX-0005kc-Je for help-gnu-emacs@gnu.org; Mon, 05 Dec 2022 21:40:19 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1p2NsR-0003GK-LD for help-gnu-emacs@gnu.org; Tue, 06 Dec 2022 03:40:11 +0100 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-Mailman-Approved-At: Tue, 06 Dec 2022 01:42:21 -0500 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:141431 Archived-At: Michael Heerdegen wrote: > What happens if you compile a file with these contents > for example? > > (defun test () > (let ((l (list 1 2))) > (push-last 2 l) > l)) Okay, this then? ;;; -*- lexical-binding: t -*- ;; ;; this file: ;; https://dataswamp.org/~incal/emacs-init/list.el (defmacro push-last (elem lst) "Push ELEM to be the last element of LST. Beware that this is O(n) while `push' is O(1)." `(if (and (symbolp ,lst) (not (symbol-value ,lst)) ) (setq ,lst (list ,elem)) (nconc ,lst (list ,elem)) )) >> Here is the `push' macro - TBH, I don't know what most of >> that means ... > > That supports generalized variables; you don't need to do > that (unless you want to). Just wonder why mine looks so different ... -- underground experts united https://dataswamp.org/~incal