From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Ihor Radchenko Newsgroups: gmane.emacs.devel Subject: defcustom :set vs. add-variable-watcher Date: Thu, 05 Jan 2023 08:06:45 +0000 Message-ID: <87a62xiewa.fsf@localhost> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="24950"; mail-complaints-to="usenet@ciao.gmane.io" To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Thu Jan 05 09:07:17 2023 Return-path: Envelope-to: ged-emacs-devel@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 1pDLHR-0006Hk-DK for ged-emacs-devel@m.gmane-mx.org; Thu, 05 Jan 2023 09:07:17 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pDLGa-0006nz-E3; Thu, 05 Jan 2023 03:06:24 -0500 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 1pDLGW-0006n1-Us for emacs-devel@gnu.org; Thu, 05 Jan 2023 03:06:20 -0500 Original-Received: from mout02.posteo.de ([185.67.36.66]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pDLGV-0006pB-32 for emacs-devel@gnu.org; Thu, 05 Jan 2023 03:06:20 -0500 Original-Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 96E1024032B for ; Thu, 5 Jan 2023 09:06:14 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1672905976; bh=4X/Xu4VTz+C89e7MNUw6Lexo28w18FuYcjTQ772VY2E=; h=From:To:Subject:Date:From; b=Qa1XymUHudAdu5K9EuaC+ua4ojlUSgPcpEUnyQFPAGFVu+G7DqIFQcsnWrLvpzOzt d53bMLdCx59g7603Si2VD4RJ+R2zsrGB9g1DcRlcdQgIjcwnWtOpG4kS+1nQRp06AX U4wFZOJ0ssCSde0wSlwfOo3XLqjaoigoDGJu2HeingAqaLQm2nYkn+sH/9v6JZNfvc XLyqCLfBJg0fjmCK2VWWx9BrBtsBn/3lXev0HTOhgOtUzTkbuoxNtmYZmRJME7BWzi LdAoEhQ8vnh11JQQeWSSCKbQ4wFHqBPeJIDP01g3KN2/MkOY2KDQv8KYAEvn9eS6I9 i+u1sxObj/GPw== Original-Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4NnfDj4ltRz9rxF for ; Thu, 5 Jan 2023 09:06:13 +0100 (CET) Received-SPF: pass client-ip=185.67.36.66; envelope-from=yantar92@posteo.net; helo=mout02.posteo.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 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, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:302235 Archived-At: Hi, AFAIK, the traditional way to provide side effects to customization value changes if :set option in `defcustom' definition. However, it has been suggested [1] that one might also utilize `add-variable-watcher' for the same purpose. Given that many users don't actually use customize interface and instead tend to set variables directly, `add-variable-watcher' looks like a more reliable option compared to :set. Are there any reasons to prefer :set over `add-variable-watcher'? Maybe some non-obvious pitfalls? [1] https://orgmode.org/list/87h6x8kluc.fsf@localhost -- Ihor Radchenko // yantar92, Org mode contributor, Learn more about Org mode at . Support Org development at , or support my work at