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

[Maxim Cournoyer]

Hello Guix!

I've rediscovered the little gem that is (guix services configurations),
and attempted to make it more generally useful by adding an option to
opt out of serialization (which is not well adapted for producing a list
of command line arguments from the configuration for example):

--8<---------------cut here---------------start------------->8---
1 file changed, 10 insertions(+), 1 deletion(-)
gnu/services/configuration.scm | 11 ++++++++++-

modified   gnu/services/configuration.scm
@@ -38,6 +38,9 @@
             configuration-field-getter
             configuration-field-default-value-thunk
             configuration-field-documentation
+
+            %with-serialization?
+
             serialize-configuration
             define-maybe
             define-configuration
@@ -51,6 +54,11 @@
 ;;;
 ;;; Code:
 
+;;; XXX: This doesn't actually work as a parameter with macros such as
+;;; define-configuration; it is to be used as a plain global variable.
+;;; Experiments with define-syntax-parameter did not work either.
+(define %with-serialization? (make-parameter #true))
+
 (define-condition-type &configuration-error &error
   configuration-error?)
 
@@ -123,7 +131,8 @@
                            #'(field-type ...)))
                      ((field-serializer ...)
                       (map (lambda (type)
-                             (id #'stem #'serialize- type))
+                             (and (%with-serialization?)
+                                  (id #'stem #'serialize- type)))
                            #'(field-type ...))))
            #`(begin
                (define-record-type* #,(id #'stem #'< #'stem #'>)
--8<---------------cut here---------------end--------------->8---

Unfortunately, it doesn't work, at least when using it from 'guix
system'.  I've also tried a version relying on syntax-parameter instead
of a parameter, with the same result.

Would someone know how it could be made to work?

Thanks,

Maxim