From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andy Wingo <wingo@igalia.com>
Subject: Re: Service refactoring
Date: Tue, 08 Sep 2015 10:47:34 +0200
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In-Reply-To: <87vbbn44zi.fsf_-_@gnu.org> ("Ludovic =?utf-8?Q?Court=C3=A8s?=
	=?utf-8?Q?=22's?= message of "Sun, 06 Sep 2015 23:23:13 +0200")
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To: Ludovic =?utf-8?Q?Court=C3=A8s?= <ludo@gnu.org>
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On Sun 06 Sep 2015 23:23, ludo@gnu.org (Ludovic Court=C3=A8s) writes:

> Service types and their =E2=80=9Cextends=E2=80=9D relations form a DAG

I am not sure how much ordering matters.  The reason is that the
"extends" relations actually proceed from packages associated with a
service, not the service itself.  It's enough to know the set of
services and their associated extends; ordering does not appear to be
important.  Of course we could do a topological sort on services for
some other reason, but we don't actually need to for these purposes.

I think a two-phase configuration can work: one, in which we specify
services like this:

  (operating-system
   ...
   (services SERVICES))

and a second in which the services are "finalized".  Finalization is a
monadic procedure of type SERVICE SERVICES -> SERVICE.  Finalization is
where e.g. udev would grovel the SERVICES to collect all udev extends.

Andy