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From: "Ludovic Courtès" <ludo@gnu.org>
To: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Cc: 56799@debbugs.gnu.org, attila@lendvai.name
Subject: bug#56799: (gnu services configuration) usage of *unspecified* is problematic
Date: Mon, 01 Aug 2022 15:49:32 +0200	[thread overview]
Message-ID: <8735egxedv.fsf@gnu.org> (raw)
In-Reply-To: <87o7xa8qxt.fsf@gmail.com> (Maxim Cournoyer's message of "Wed, 27 Jul 2022 12:23:58 -0400")

Hi!

Maxim Cournoyer <maxim.cournoyer@gmail.com> 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
<https://issues.guix.gnu.org/54674> was to specifically use a “special”
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 ‘define-maybe’ and appropriate field
serializers such that *unspecified* never goes through.  Previously
you’d check for (eq? x 'disabled) and now you just check for
(unspecified? x).

Thanks,
Ludo’.




  parent reply	other threads:[~2022-08-01 13:58 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-27 16:23 bug#56799: (gnu services configuration) usage of *unspecified* is problematic Maxim Cournoyer
2022-07-27 16:43 ` Tobias Geerinckx-Rice via Bug reports for GNU Guix
2022-07-27 18:27   ` Attila Lendvai
2022-07-28 15:15     ` Maxim Cournoyer
2022-07-27 18:31   ` Maxim Cournoyer
2022-07-27 18:45     ` Tobias Geerinckx-Rice via Bug reports for GNU Guix
2022-07-27 19:09       ` Maxim Cournoyer
2022-07-27 19:45         ` bug#56799: [PATCH] services: configuration: Step back from *unspecified* Maxim Cournoyer
2022-07-27 19:46         ` bug#56799: (gnu services configuration) usage of *unspecified* is problematic Maxim Cournoyer
2022-07-27 20:20           ` bug#56799: [PATCH v2] gexp: Handle *unspecified* as a gexp input Maxim Cournoyer
2022-07-27 21:43             ` Maxime Devos
2022-07-28 14:58               ` Maxim Cournoyer
2022-07-28  4:41           ` bug#56799: [PATCH v3] " Maxim Cournoyer
2022-08-01  5:08             ` bug#56799: (gnu services configuration) usage of *unspecified* is problematic Maxim Cournoyer
2022-08-01 10:00               ` Maxime Devos
2022-08-01 12:46                 ` Maxim Cournoyer
2022-08-01 13:44             ` Ludovic Courtès
2022-08-01 16:55       ` Maxim Cournoyer
2022-07-28  4:55     ` bokr
2022-07-28 10:26       ` Maxime Devos
2022-07-28 15:09         ` Maxim Cournoyer
2022-08-01 13:49 ` Ludovic Courtès [this message]
2022-08-01 15:55   ` Maxim Cournoyer
2022-08-02  7:31     ` Ludovic Courtès
2022-08-02  8:45       ` bokr
2022-08-02 15:06       ` Maxim Cournoyer
2022-08-04 12:19         ` Ludovic Courtès
2022-08-07 22:44           ` Ludovic Courtès
2022-08-08 22:27           ` Attila Lendvai
2022-08-08 23:35             ` Attila Lendvai
2022-08-10  2:17               ` Maxim Cournoyer
2022-08-10  3:26             ` Maxim Cournoyer
2022-08-11 10:15               ` Attila Lendvai
2022-08-13  6:31                 ` Maxim Cournoyer
2022-08-13 16:47                   ` Attila Lendvai
2022-08-14  2:57                     ` Maxim Cournoyer
2022-08-16 14:00                       ` Attila Lendvai
2022-08-17 13:16                         ` Maxim Cournoyer
2022-08-17 16:00                           ` paren--- via Bug reports for GNU Guix
2022-08-10  0:43           ` Maxim Cournoyer
2022-08-24 12:40 ` bug#56799: [PATCH 1/5] services: configuration: Add a 'maybe-value-set?' procedure Attila Lendvai
2022-08-24 12:40   ` bug#56799: [PATCH 2/5] services: configuration: Add %unset-value exported variable Attila Lendvai
2022-08-24 12:40   ` bug#56799: [PATCH 3/5] services: configuration: Add maybe-value exported procedure Attila Lendvai
2022-08-24 12:40   ` bug#56799: [PATCH 4/5] services: Use the new maybe/unset API Attila Lendvai
2022-08-25  4:18     ` bug#56799: (gnu services configuration) usage of *unspecified* is problematic Maxim Cournoyer
2022-08-24 12:40   ` bug#56799: [PATCH 5/5] services: configuration: Change the value of the unset marker Attila Lendvai
2022-08-25  4:14     ` bug#56799: (gnu services configuration) usage of *unspecified* is problematic Maxim Cournoyer

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