From debbugs-submit-bounces@debbugs.gnu.org Mon Aug 01 09:49:44 2022 Received: (at 56799) by debbugs.gnu.org; 1 Aug 2022 13:49:44 +0000 Received: from localhost ([127.0.0.1]:39807 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1oIVnk-0006GZ-0e for submit@debbugs.gnu.org; Mon, 01 Aug 2022 09:49:44 -0400 Received: from eggs.gnu.org ([209.51.188.92]:52606) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1oIVni-0006GK-TG for 56799@debbugs.gnu.org; Mon, 01 Aug 2022 09:49:43 -0400 Received: from fencepost.gnu.org ([2001:470:142:3::e]:49968) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oIVnd-0005kN-2a; Mon, 01 Aug 2022 09:49:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-Version:In-Reply-To:Date:References:Subject:To: From; bh=2ekT+tTRENRxdGBSfhjt6g28WlZFWc2oPcP+lcokCTM=; b=erwOkQzSS8DbooHJ6ioE cr+Cpd3GBMdSKbf73tFtlfdi9Zbntwg43xiQuTc36Zz/NsjtaGZGUxsVnwBhKi7YBNaY20MIAoZz4 wkMK4Xvt+F7NwqLyZir4sEPMJe96f570Y2ZIRlLLDaC4rCLCgQFBFUwxjru8PJ0+1wOHNBjLs1jdJ JdhyHDrtP+0dTPVFjtmaajtwD9YYVPZ6KqaUXtRbxg+BKmexzz71wL3xf+VzhELzqT4mpkqV/MOIR 9EZ95QCWlxBNgXBi2bHZqxdx77jqMXSl1+DheNbU/eglnfLczQAefQ5XYj2PGoJNBtRFw7gQpJor8 tbTKY0wQQpqVsw==; Received: from [2001:660:6102:310:f6b5:dff0:8fea:f7c9] (port=48522 helo=ribbon) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oIVnb-0005Bh-Pt; Mon, 01 Aug 2022 09:49:36 -0400 From: =?utf-8?Q?Ludovic_Court=C3=A8s?= To: Maxim Cournoyer Subject: Re: bug#56799: (gnu services configuration) usage of *unspecified* is problematic References: <87o7xa8qxt.fsf@gmail.com> Date: Mon, 01 Aug 2022 15:49:32 +0200 In-Reply-To: <87o7xa8qxt.fsf@gmail.com> (Maxim Cournoyer's message of "Wed, 27 Jul 2022 12:23:58 -0400") Message-ID: <8735egxedv.fsf@gnu.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 56799 Cc: 56799@debbugs.gnu.org, attila@lendvai.name X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.3 (---) Hi! Maxim Cournoyer skribis: > Since commit 8cb1a49a3998c39f315a4199b7d4a121a6d66449, the > define-configuration machinery in (gnu services configuration) uses > *unspecified* instead of 'disabled for an unspecified field value. As Attila wrote, the rationale as discussed in was to specifically use a =E2=80=9Cspec= ial=E2=80=9D value without a read syntax in lieu of a symbol like 'disabled. > While this is indeed an improvement in readability, it introduces an > extra complication: because this new value is not self-quoting, it > cannot be used as is in G-Exps, and values using it must be carefully > expanded outside the gexp context, which is error prone. Could you give a simple example of how this can happen? In my experience, one would use =E2=80=98define-maybe=E2=80=99 and appropri= ate field serializers such that *unspecified* never goes through. Previously you=E2=80=99d check for (eq? x 'disabled) and now you just check for (unspecified? x). Thanks, Ludo=E2=80=99.