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From: Maxim Cournoyer <maxim.cournoyer@gmail.com>
To: Tobias Geerinckx-Rice <me@tobias.gr>
Cc: 56799@debbugs.gnu.org, attila@lendvai.name
Subject: bug#56799: (gnu services configuration) usage of *unspecified* is problematic
Date: Wed, 27 Jul 2022 14:31:32 -0400	[thread overview]
Message-ID: <87fsim8l17.fsf@gmail.com> (raw)
In-Reply-To: <87a68uqz9r@nckx> (Tobias Geerinckx-Rice's message of "Wed, 27 Jul 2022 18:43:25 +0200")

Hi,

Tobias Geerinckx-Rice <me@tobias.gr> writes:

> Hi Maxim,
>
> Maxim Cournoyer 写道:
>> I'd suggest we revisit 8cb1a49a3998c39f315a4199b7d4a121a6d66449 to
>> use
>> 'unspecified (the symbol) instead of *unspecified*, which *can* be
>> serialized without any fuss in gexps.
>
> Bah.  Could we provide our own reader?
>
> I'd much rather this be addressed in Guile (or failing that,
> transparently by Guix) than have to deal with some magical
> symbol. IIRC that was the argument for using *unspecified* in the
> first place, and I think it makes sense.
>
> This looks more like an unexplored oversight than a well-reasoned
> restriction to me.

This was my original impression, but thinking more about it, it became
apparent that *unspecified* is well, unspecified and shouldn't be relied
on by people to be something well defined.  For some background reading,
see [0].  So it seems wrong in Scheme to actively set things to
*unspecified*, and give a specific meaning to that.

I think the semantic of the language is that it is to be used as the
lack of a return value from a procedure or syntax, e.g.:

(unspecified? (if #f 'one-arm-if)) -> #t

Having 'unspecified?' even defined in Guile seems to go against that
idea; perhaps because Wingo themselves seems to disagree in [0].

I'm also thinking 'unspecified being too close to *unspecified* is
probably going to cause confusion down the line.  Reverting to the
originally used 'disabled may be the lesser evil.

Other thoughts?

Thanks,

Maxim

[0]  https://scheme-reports.scheme-reports.narkive.com/QSQtJSAh/unspecified-values




  parent reply	other threads:[~2022-07-27 19:13 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 [this message]
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
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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