From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.help Subject: Re: EIEIO: A question about interfaces Date: Fri, 15 Jan 2021 11:21:42 -0500 Message-ID: References: <877dofee8e.fsf@web.de> <87turih1z8.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="30907"; 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:WdcBzKf4uuDrI5gwB+QHDibMg7Q= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Fri Jan 15 17:22:26 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 1l0Rrm-0007oT-2x for geh-help-gnu-emacs@m.gmane-mx.org; Fri, 15 Jan 2021 17:22:26 +0100 Original-Received: from localhost ([::1]:57912 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l0Rrl-0005gq-4F for geh-help-gnu-emacs@m.gmane-mx.org; Fri, 15 Jan 2021 11:22:25 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54144) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l0RrE-0005fS-A1 for help-gnu-emacs@gnu.org; Fri, 15 Jan 2021 11:21:52 -0500 Original-Received: from ciao.gmane.io ([116.202.254.214]:58096) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l0RrB-0000EN-VL for help-gnu-emacs@gnu.org; Fri, 15 Jan 2021 11:21:52 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1l0Rr9-00070k-Fa for help-gnu-emacs@gnu.org; Fri, 15 Jan 2021 17:21:47 +0100 X-Injected-Via-Gmane: http://gmane.org/ 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:127260 Archived-At: >> In your example, that might mean you'd create a new class that inherits >> from both `my-1` and `my-foo-interface`. > But in the general case, when I have a hierarchy of N classes instead of > only one `my-1`, does that mean that I have to create a parallel > hierarchy of N classes? If you really might use all combinations, then maybe you should rather look at `my-foo-interface` as a separate type where one of its fields might be of type `my-1`, `my-2`, ... Stefan