bug#53663: closed ([PATCH] gnu: services: Also accept 'undefined in maybe-foo? constructs.)

[GNU bug Tracking System]

Your message dated Wed, 02 Feb 2022 11:47:02 +0000
with message-id 
<LZAnSJmgmdtLPRzpDhrfzSlilVJJq1MLXCWIIkE-yMLDeEXnFN5wPrWeMGAjZGo2vl1yUKPrilT3nCtusH9frolHVuqEM9boV1MLWgVr64U=@lendvai.name>
and subject line Fw: Re: bug#53663: [PATCH] gnu: services: Also accept 
'undefined in maybe-foo? constructs.
has caused the debbugs.gnu.org bug report #53663,
regarding [PATCH] gnu: services: Also accept 'undefined in maybe-foo? 
constructs.
to be marked as done.

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53663: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=53663
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> --- Begin Message ---
>
>
>
> Subject: 
>
> [PATCH] gnu: services: Also accept 'undefined in maybe-foo? constructs.
>
>
>
>
> Date: 
>
> Mon, 31 Jan 2022 16:27:54 +0100
>
>
>
>
> This is a temporary bandaid until a more explicit handling of maybe types is
> introduced for configurations (e.g. by using srfi-189). Until then, with this
> change it becomes possible to have definitions like:
>
> (define-maybe string (no-serialization))
>
> (define-configuration my-configuration
>   (my-field (maybe-string))
>   (no-serialization))
>
> i.e. without providing a default value for MY-FIELD.
> ---
>  gnu/services/configuration.scm | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/gnu/services/configuration.scm b/gnu/services/configuration.scm
> index 0de350a4df..c5f276eab5 100644
> --- a/gnu/services/configuration.scm
> +++ b/gnu/services/configuration.scm
> @@ -141,7 +141,9 @@ (define (define-maybe-helper serialize? prefix syn)
>                                      (id #'stem #'serialize-maybe- #'stem))))
>         #`(begin
>             (define (maybe-stem? val)
> -             (or (eq? val 'disabled) (stem? val)))
> +             (or (eq? val 'disabled)
> +                 (eq? val 'undefined)
> +                 (stem? val)))
>             #,@(if serialize?
>                    (list #'(define (serialize-maybe-stem field-name val)
>                              (if (stem? val)
> -- 
> 2.34.0
>
>
>
>
> --- End Message ---
> --- Begin Message ---
>
>
>
> Subject: 
>
> Fw: Re: bug#53663: [PATCH] gnu: services: Also accept 'undefined in maybe-foo? constructs.
>
>
>
>
> Date: 
>
> Wed, 02 Feb 2022 11:47:02 +0000
>
>
>
>
> > What would be different here?
>
> the possibility of writing:
>
> (define-configuration my-cfg
>   (my-field (maybe-string)))
>
> versus now having to write:
>
> (define-configuration my-cfg
>   (my-field (maybe-string 'disabled)))
>
> but now that i thought about it, i think everyone is better off if i
> deal with this on my side, instead of having a discussion about the
> exact shape of a bandaid.
>
> closing this for now; more later in the form of a proper cleanup
> proposal of the configuration code.
>
> --
> • attila lendvai
> • PGP: 963F 5D5F 45C7 DFCD 0A39
> --
> “There can be no greater stretch of arbitrary power than is required to seize 
> children from their parents, teach them whatever the authorities decree they 
> shall be taught, and expropriate from the parents the funds to pay for the 
> procedure.”
>         — Isabel Paterson (1886–1961), 'The God of the Machine' (1943)
>
>
>
> --- End Message ---