Re: Add a way to disable serialization support to (guix services configuration)

[Maxim Cournoyer]

Hello again,

Ludovic Courtès <ludo@gnu.org> writes:

[...]

> diff --git a/gnu/services/configuration.scm b/gnu/services/configuration.scm
> index 90f12a8d39..20e1647335 100644
> --- a/gnu/services/configuration.scm
> +++ b/gnu/services/configuration.scm
> @@ -109,6 +109,9 @@
>               (define (serialize-maybe-stem field-name val)
>                 (if (stem? val) (serialize-stem field-name val) ""))))))))
>
> +(define-syntax-parameter configuration-field-serialization?
> +  (identifier-syntax #t))
> +
>  (define-syntax define-configuration
>    (lambda (stx)
>      (syntax-case stx ()
> @@ -123,7 +126,8 @@
>                             #'(field-type ...)))
>                       ((field-serializer ...)
>                        (map (lambda (type)
> -                             (id #'stem #'serialize- type))
> +                             #`(and configuration-field-serialization?
> +                                    #,(id #'stem #'serialize- type)))
>                             #'(field-type ...))))
>             #`(begin
>                 (define-record-type* #,(id #'stem #'< #'stem #'>)
> @@ -152,6 +156,16 @@
>                                             #,(id #'stem #'stem #'-fields))
>                     conf))))))))
>
> +(define-syntax-rule (without-field-serialization definition)
> +  (syntax-parameterize ((configuration-field-serialization?
> +                         (identifier-syntax #f)))
> +    definition
> +    #t))
> +
> +(without-field-serialization
> +  (define-configuration foo
> +    (bar (integer 123) "doc")))
> +
>  (define (serialize-package field-name val)
>    "")

Actually, this doesn't seem to work; when exporting the
'without-field-serialization' from this module and using it in another
module (wrapping a (define-configuration ...) form), the compiler
complains that the 'foo' variable is not defined; perhaps because foo is
exported as part of the module definition?

If you have an idea why, hints welcome.

Maxim