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: Is there any difference between `equal' and `string=' for strings? Date: Fri, 20 Aug 2021 08:35:33 +0300 Message-ID: References: <875yw2vxqh.fsf@mbork.pl> <87r1epdo2q.fsf@zoho.eu> 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="10529"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mutt/2.0.7+183 (3d24855) (2021-05-28) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Fri Aug 20 07:36:56 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 1mGxD5-0002TV-Ri for geh-help-gnu-emacs@m.gmane-mx.org; Fri, 20 Aug 2021 07:36:55 +0200 Original-Received: from localhost ([::1]:37684 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mGxD3-0000w8-LS for geh-help-gnu-emacs@m.gmane-mx.org; Fri, 20 Aug 2021 01:36:53 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:58058) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mGxCi-0000w0-2j for help-gnu-emacs@gnu.org; Fri, 20 Aug 2021 01:36:32 -0400 Original-Received: from stw1.rcdrun.com ([217.170.207.13]:51957) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mGxCg-0006n2-HL for help-gnu-emacs@gnu.org; Fri, 20 Aug 2021 01:36:31 -0400 Original-Received: from localhost ([::ffff:154.230.131.13]) (AUTH: PLAIN admin, TLS: TLS1.3,256bits,ECDHE_RSA_AES_256_GCM_SHA384) by stw1.rcdrun.com with ESMTPSA id 0000000000069CB1.00000000611F3F5C.00004DFA; Thu, 19 Aug 2021 22:36:27 -0700 Mail-Followup-To: help-gnu-emacs@gnu.org Content-Disposition: inline In-Reply-To: <87r1epdo2q.fsf@zoho.eu> Received-SPF: pass client-ip=217.170.207.13; envelope-from=bugs@gnu.support; helo=stw1.rcdrun.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, 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: 2.1.23 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:132621 Archived-At: * Emanuel Berg via Users list for the GNU Emacs text editor [2021-08-20 02:16]: > Jean Louis wrote: > > > (string-equal 123 "123") -- gives error, as string= is alias > > for string-equal that is to handle exclusively strings. > > Nope, you can pass symbols as well: > > (string= "hi" "hi") ; t > (string= 'hi "hi") ; t > (string= 'hi 'hi ) ; t > > > (equalp 123 "123") > > `equalp'? Aren't you the one who doesn't like Elisp CL? You eagle eye! I really did not notice it. Maybe it is due to Common Lisp handy habit. I have (almost) no "equalp" in my Emacs Lisp, just in comments. > Anyway careful with `equalp' for strings, note that > > (cl-equalp "Hi" "hi") ; t On the other hand that is handy when testing for file extensions like .jpg and .JPG otherwise I downcase it all before the test. > > Sometimes program outputs different types, could be `nil' or > > `string' and those outputs maybe need to be expected as any > > type or as exclusively strings. That is where the difference > > comes handy, as sometimes I do want to get error report. > > If I wish to test strings I better use `string=' > > It is a jungle, the rule of thumb I think is > > `eq' to answer the question "is it the same Lisp object"? > > `=' to compare numbers in the math sense > > `string=' for strings only > > `equal' for everything else, except ... > > `cl-equalp' I give up ;) Equalp is very handy. -- Jean Take action in Free Software Foundation campaigns: https://www.fsf.org/campaigns In support of Richard M. Stallman https://stallmansupport.org/