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: Is there any difference between `equal' and `string=' for strings? Date: Sat, 21 Aug 2021 01:42:14 +0200 Message-ID: <87h7fj8yzt.fsf@zoho.eu> References: <875yw2vxqh.fsf@mbork.pl> <87v941domi.fsf@zoho.eu> <87tujkd46u.fsf@zoho.eu> <87lf4wd3dz.fsf@zoho.eu> <87lf4v90e2.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="645"; 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:pfSJB+mfsNHY4wwpw0JchO6B/SI= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sat Aug 21 01:43:02 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 1mHEAA-000AXQ-1h for geh-help-gnu-emacs@m.gmane-mx.org; Sat, 21 Aug 2021 01:43:02 +0200 Original-Received: from localhost ([::1]:34284 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mHEA8-0008C6-DI for geh-help-gnu-emacs@m.gmane-mx.org; Fri, 20 Aug 2021 19:43:00 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:48710) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mHE9c-0008Bx-ET for help-gnu-emacs@gnu.org; Fri, 20 Aug 2021 19:42:28 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:54158) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mHE9a-0001TW-PY for help-gnu-emacs@gnu.org; Fri, 20 Aug 2021 19:42:28 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1mHE9Y-0009xf-SD for help-gnu-emacs@gnu.org; Sat, 21 Aug 2021 01:42:24 +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:132630 Archived-At: >> (defun do-something (method) >> (when (string= method "now") >> (message "I'm all over it") )) > > What about > > (defun get-string (s) > (if (stringp s) > s > (let ((val (symbol-value s))) > (or (and (stringp val) val) > (symbol-name s) )))) > > (defun string== (s1 s2) > (string= (get-string s1) > (get-string s2) )) Maybe one should rationalize everything down into "same" - same object is t, else nil "equal-all" - same type _and_ equal data is t, else nil (for this purpose, the predicates, e.g., `stringp' would imply the existence of a type) "equal-data" - equal data, here it would have to be set up on a case-by-case basis for all the types, so while obviously for `integerp' and `floatp' (equal-data 2 2.0) but one can think of a lot more, for example (equal-data "data" '(?d ?a ?t ?a)) ; t and so on. Not saying one should change Lisp tho, just to theorize what it could be I mean ... What does the computer science (or perhaps login/math science?) of "type theory" have to say about all this? :) No, really? Did all the equality functions arrive little by little or was there a plane? A little bit of both perhaps? All the overlap are implementation/optimization derived things, right? -- underground experts united https://dataswamp.org/~incal