services: Move configuration functions that shouldn't be factorized.

* gnu/services/configuration.scm (serialize-field, serialize-string)
(serialize-space-separated-string-list, space-separated-string-list?)
(serialize-file-name, file-name?, serialize-boolean): Move these functions...
* gnu/services/cups.scm: ...to this file.
* gnu/services/kerberos.scm: ...to this file.

Configuration syntaxes are very specific to services.  Some services may have
the same configuration syntax, but none of them is common enough to be
abstracted in configuration.scm.

Signed-off-by: Clément Lassieur <clement@lassieur.org>

gnu/services/configuration.scm

@@ -39,14 +39,6 @@
             define-configuration
             validate-configuration
             generate-documentation
-            serialize-field
-            serialize-string
-            serialize-name
-            serialize-space-separated-string-list
-            space-separated-string-list?
-            serialize-file-name
-            file-name?
-            serialize-boolean
             serialize-package))
 
 ;;; Commentary:
@@ -140,41 +132,9 @@
                                            #,(id #'stem #'stem #'-fields))
                    conf))))))))
 
-(define (uglify-field-name field-name)
-  (let ((str (symbol->string field-name)))
-    (string-concatenate
-     (map string-titlecase
-          (string-split (if (string-suffix? "?" str)
-                            (substring str 0 (1- (string-length str)))
-                            str)
-                        #\-)))))
-
-(define (serialize-field field-name val)
-  (format #t "~a ~a\n" (uglify-field-name field-name) val))
-
 (define (serialize-package field-name val)
   #f)
 
-(define (serialize-string field-name val)
-  (serialize-field field-name val))
-
-(define (space-separated-string-list? val)
-  (and (list? val)
-       (and-map (lambda (x)
-                  (and (string? x) (not (string-index x #\space))))
-                val)))
-(define (serialize-space-separated-string-list field-name val)
-  (serialize-field field-name (string-join val " ")))
-
-(define (file-name? val)
-  (and (string? val)
-       (string-prefix? "/" val)))
-(define (serialize-file-name field-name val)
-  (serialize-string field-name val))
-
-(define (serialize-boolean field-name val)
-  (serialize-string field-name (if val "yes" "no")))
-
 ;; A little helper to make it easier to document all those fields.
 (define (generate-documentation documentation documentation-name)
   (define (str x) (object->string x))

gnu/services/cups.scm

@@ -57,6 +57,21 @@
          (home-directory "/var/empty")
          (shell (file-append shadow "/sbin/nologin")))))
 
+(define (uglify-field-name field-name)
+  (let ((str (symbol->string field-name)))
+    (string-concatenate
+     (map string-titlecase
+          (string-split (if (string-suffix? "?" str)
+                            (substring str 0 (1- (string-length str)))
+                            str)
+                        #\-)))))
+
+(define (serialize-field field-name val)
+  (format #t "~a ~a\n" (uglify-field-name field-name) val))
+
+(define (serialize-string field-name val)
+  (serialize-field field-name val))
+
 (define (multiline-string-list? val)
   (and (list? val)
        (and-map (lambda (x)
@@ -65,11 +80,28 @@
 (define (serialize-multiline-string-list field-name val)
   (for-each (lambda (str) (serialize-field field-name str)) val))
 
+(define (space-separated-string-list? val)
+  (and (list? val)
+       (and-map (lambda (x)
+                  (and (string? x) (not (string-index x #\space))))
+                val)))
+(define (serialize-space-separated-string-list field-name val)
+  (serialize-field field-name (string-join val " ")))
+
 (define (space-separated-symbol-list? val)
   (and (list? val) (and-map symbol? val)))
 (define (serialize-space-separated-symbol-list field-name val)
   (serialize-field field-name (string-join (map symbol->string val) " ")))
 
+(define (file-name? val)
+  (and (string? val)
+       (string-prefix? "/" val)))
+(define (serialize-file-name field-name val)
+  (serialize-string field-name val))
+
+(define (serialize-boolean field-name val)
+  (serialize-string field-name (if val "yes" "no")))
+
 (define (non-negative-integer? val)
   (and (exact-integer? val) (not (negative? val))))
 (define (serialize-non-negative-integer field-name val)

gnu/services/kerberos.scm

@@ -96,6 +96,12 @@ trailing '?' removed."
   (unless (eq? val unset-field)
       (serialize-field* field-name (string-join val " "))))
 
+(define (space-separated-string-list? val)
+  (and (list? val)
+       (and-map (lambda (x)
+                  (and (string? x) (not (string-index x #\space))))
+                val)))
+
 (define space-separated-string-list/unset?
   (predicate/unset space-separated-string-list?))
 
@@ -118,10 +124,19 @@ trailing '?' removed."
                     (lambda (val)
                       (string-prefix? "/" val))))
 
+(define (serialize-field field-name val)
+  (format #t "~a ~a\n" (uglify-field-name field-name) val))
+
+(define (serialize-string field-name val)
+  (serialize-field field-name val))
+
 (define (serialize-file-name field-name val)
   (unless (eq? val unset-field)
     (serialize-string field-name val)))
 
+(define (serialize-space-separated-string-list field-name val)
+  (serialize-field field-name (string-join val " ")))
+
 (define (non-negative-integer? val)
   (and (exact-integer? val) (not (negative? val))))