From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Heime Newsgroups: gmane.emacs.help Subject: RE: [External] : Re: cond construct for situation when a variable is t Date: Tue, 22 Aug 2023 20:21:22 +0000 Message-ID: References: <87o7j2d6yd.fsf@dataswamp.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="34487"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Emanuel Berg , "help-gnu-emacs@gnu.org" To: Drew Adams Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Tue Aug 22 22:22:22 2023 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 1qYXtO-0008py-6t for geh-help-gnu-emacs@m.gmane-mx.org; Tue, 22 Aug 2023 22:22:22 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qYXsr-0006eK-0r; Tue, 22 Aug 2023 16:21:49 -0400 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 1qYXsp-0006eA-MJ for help-gnu-emacs@gnu.org; Tue, 22 Aug 2023 16:21:48 -0400 Original-Received: from mail-40138.protonmail.ch ([185.70.40.138]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qYXsn-0002jY-35 for help-gnu-emacs@gnu.org; Tue, 22 Aug 2023 16:21:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1692735694; x=1692994894; bh=SK9z8Wc8HY0lKl7IPjZ8zlUXBxQctAE3xIbxVZUbn70=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=tOU0IGWW5o6Z68hkeq4svPhr5Mt6JiuQCJg+MnsZlTVWC2GAnD0/v3ZJga7Yguc3g PlcnbwqhNP+R0Um8XMySrqjth1eomwOH9o9XjQyZDUFPK07LfippVD4+5L0xRh0cCH NQJe53kzd5ex5K/9bEhT9c642nPMZ26VSeZ/jgT2d/QWGw+wN9cOeWa/veQv0/xtmg oZTSMsIFGMqqEW86RRiH+chAtsD2CHQEQWiFwzibUvy9za4TT8mD9ThDHBQsn1Psi/ ghvM+bSDC4hx2JvSc02bpjrvVpdaEGu0J0jCVedkh9qqISkLTy0mDvsnoFbrt88D1i pkV39MgoeY1zQ== In-Reply-To: Feedback-ID: 57735886:user:proton Received-SPF: pass client-ip=185.70.40.138; envelope-from=heimeborgia@protonmail.com; helo=mail-40138.protonmail.ch X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham 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:144921 Archived-At: Sent with Proton Mail secure email. ------- Original Message ------- On Wednesday, August 23rd, 2023 at 4:17 AM, Drew Adams wrote: > > There is no 'boolean datatype' in elisp. > > With nil and empty list () being false, > > anything else is true. >=20 >=20 > There's no real true or false in Lisp. But yes, > that's the convention, and that convention is > baked into primitive conditionals, such as `if' and` cond'. So sure, you = can think of it as > being more than a convention. >=20 > > That t is used for true, is that by convention ? > > Should t be used, or is it unreliable ? >=20 >=20 > Just like the "convention" described above, it's > a convention. But also just like it, it's baked > into primitives. So yes, the constant `t' is a > typical non-nil value used by conditionals to > represent "true". And it's the canonical way to > represent "true", meaning that it's the clearest > way to tell human readers of code that "true" is > meant. The canonical convention also stipulates that the symbol t is not to be modified to something else though, am I right ?