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: Elisp string function question Date: Sun, 20 Jun 2021 03:26:32 +0200 Message-ID: <878s354987.fsf@zoho.eu> References: <20210618121807.xsjdbv4ouqbv4uex.ref@Ergus> <20210618121807.xsjdbv4ouqbv4uex@Ergus> <87pmwi50hn.fsf@zoho.eu> <87h7ht4a11.fsf@zoho.eu> <87czsh49qy.fsf@zoho.eu> 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="25898"; 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:YzAUy7l7IB9bGHFWdR/Pa4UhI18= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sun Jun 20 03:27:13 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 1lumEz-0006ZS-1x for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 20 Jun 2021 03:27:13 +0200 Original-Received: from localhost ([::1]:58860 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lumEy-0006f1-3b for geh-help-gnu-emacs@m.gmane-mx.org; Sat, 19 Jun 2021 21:27:12 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54620) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lumEV-0006ep-TR for help-gnu-emacs@gnu.org; Sat, 19 Jun 2021 21:26:43 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:41506) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lumEU-0003YZ-Hq for help-gnu-emacs@gnu.org; Sat, 19 Jun 2021 21:26:43 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1lumES-0005rM-S6 for help-gnu-emacs@gnu.org; Sun, 20 Jun 2021 03:26:40 +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:131060 Archived-At: > What I want is > > (defun string-data-p (str) > (and (stringp str) > (not (string= str "")) )) > > Is it a string? > > Does it have data? (string-data-p nil) ; nil (string-data-p "") ; nil (string-data-p "ready for takeoff") ; t But that is actually much better! It is much clearer to ask if something is ready than to ask if something isn't empty! Now I can use `when' instead of `unless', or have it as the first branch of `if's without an`not'! Much better! -- underground experts united https://dataswamp.org/~incal