From mboxrd@z Thu Jan 1 00:00:00 1970 From: "pelzflorian (Florian Pelz)" Subject: bug#34955: Manual: Service extensions not clear Date: Sat, 23 Mar 2019 16:46:21 +0100 Message-ID: <20190323154621.u5kjvvgcci7ikrbt@pelzflorian.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Return-path: Received: from eggs.gnu.org ([209.51.188.92]:47829) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h7irP-00071p-Vz for bug-guix@gnu.org; Sat, 23 Mar 2019 11:47:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h7irP-0005K6-0f for bug-guix@gnu.org; Sat, 23 Mar 2019 11:47:03 -0400 Received: from debbugs.gnu.org ([209.51.188.43]:42146) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1h7irO-0005Jz-Qf for bug-guix@gnu.org; Sat, 23 Mar 2019 11:47:02 -0400 Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1h7irO-0006wC-N3 for bug-guix@gnu.org; Sat, 23 Mar 2019 11:47:02 -0400 Sender: "Debbugs-submit" Resent-Message-ID: Received: from eggs.gnu.org ([209.51.188.92]:47694) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h7iqn-00071J-2u for bug-guix@gnu.org; Sat, 23 Mar 2019 11:46:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h7iqm-0004p0-2A for bug-guix@gnu.org; Sat, 23 Mar 2019 11:46:25 -0400 Received: from pelzflorian.de ([5.45.111.108]:53164 helo=mail.pelzflorian.de) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1h7iql-0004lv-HW for bug-guix@gnu.org; Sat, 23 Mar 2019 11:46:23 -0400 Received: from pelzflorian.localdomain (unknown [5.45.111.108]) by mail.pelzflorian.de (Postfix) with ESMTPSA id 84AFC360038 for ; Sat, 23 Mar 2019 16:46:21 +0100 (CET) Content-Disposition: inline List-Id: Bug reports for GNU Guix List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-guix-bounces+gcggb-bug-guix=m.gmane.org@gnu.org Sender: "bug-Guix" To: 34955@debbugs.gnu.org The Guix manual (section Defining services) says about service extensions: [The example guix-service-type definition] defines three things: 1. [=E2=80=A6] 2. A list of =E2=80=9Cservice extensions=E2=80=9D, where each extension= designates the target service type and a procedure that, given the parameters of the service, returns a list of objects to extend the service of that type. Every service type has at least one service extension. The only exception is the =E2=80=9Cboot service type=E2=80=9D, which is the u= ltimate service. This is confusing to me because previously it was explained that services extend services but now it says types extend types which does not fit the previous explanation. Later it says: There can be only one instance of an extensible service type such as UDEV-SERVICE-TYPE. If there were more, the =E2=80=98service-extension=E2= =80=99 specifications would be ambiguous. I believe before the example for the definition of service types, service extensions should be explained. E.g. A service type definition specifies which services can be extended by an instance of the service type. For each service extension, exactly one service of the target service type of the extension must appear in the services field of the operating-system declaration. Regards, Florian