diff options
| -rw-r--r-- | doc/guix.texi | 7 | ||||
| -rw-r--r-- | gnu/services/configuration.scm | 15 |
2 files changed, 16 insertions, 6 deletions
diff --git a/doc/guix.texi b/doc/guix.texi index 023b48ae35..c8f18a1482 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -39003,7 +39003,7 @@ to be a string, or left unspecified. (name ;; If set to a string, the `serialize-string' procedure will be used ;; to serialize the string. Otherwise this field is not serialized. - maybe-string ; equivalent to (maybe-string *unspecified*) + maybe-string "The name of this module.")) @end lisp @@ -39034,6 +39034,11 @@ whether its value is set or not. @end lisp @end deffn +@deffn (Scheme Procedure) maybe-value-set? @var{value} +Predicate to check whether a user explicitly specified the value of a +maybe field. +@end deffn + @deffn {Scheme Procedure} serialize-configuration @var{configuration} @ @var{fields} Return a G-expression that contains the values corresponding to the diff --git a/gnu/services/configuration.scm b/gnu/services/configuration.scm index 3007e8de35..e2c4fe9998 100644 --- a/gnu/services/configuration.scm +++ b/gnu/services/configuration.scm @@ -57,6 +57,7 @@ serialize-configuration define-maybe define-maybe/no-serialization + maybe-value-set? generate-documentation configuration->documentation empty-serializer @@ -142,7 +143,8 @@ does not have a default value" field kind))) (id #'stem #'serialize-maybe- #'stem)))) #`(begin (define (maybe-stem? val) - (or (eq? val 'unset) (stem? val))) + (or (not (maybe-value-set? val)) + (stem? val))) #,@(if serialize? (list #'(define (serialize-maybe-stem field-name val) (if (stem? val) @@ -260,11 +262,10 @@ does not have a default value" field kind))) (default-value-thunk (lambda () (display '#,(id #'stem #'% #'stem)) - (if (eq? (syntax->datum field-default) - 'unset) + (if (maybe-value-set? (syntax->datum field-default)) + field-default (configuration-missing-default-value - '#,(id #'stem #'% #'stem) 'field) - field-default))) + '#,(id #'stem #'% #'stem) 'field)))) (documentation doc)) ...)))))))) @@ -300,6 +301,10 @@ does not have a default value" field kind))) (define (empty-serializer field-name val) "") (define serialize-package empty-serializer) +(define (maybe-value-set? value) + "Predicate to check whether a 'maybe' value was explicitly provided." + (not (eq? 'unset value))) + ;; A little helper to make it easier to document all those fields. (define (generate-documentation documentation documentation-name) (define (str x) (object->string x)) |