[PATCH 2/5] service: Improve style of 'for-each-service'.

[Alex Kost <alezost@gmail.com>]

* modules/shepherd/service.scm (lookup-canonical-service): New procedure.
(for-each-service): Use it.  Use 'hash-for-each' instead of 'hash-fold'.
---
 modules/shepherd/service.scm | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/modules/shepherd/service.scm b/modules/shepherd/service.scm
index 808372c..7cf557f 100644
--- a/modules/shepherd/service.scm
+++ b/modules/shepherd/service.scm
@@ -2,6 +2,7 @@
 ;; Copyright (C) 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
 ;; Copyright (C) 2002, 2003 Wolfgang Järling <wolfgang@pro-linux.de>
 ;; Copyright (C) 2014 Alex Sassmannshausen <alex.sassmannshausen@gmail.com>
+;; Copyright (C) 2016 Alex Kost <alezost@gmail.com>
 ;;
 ;; This file is part of the GNU Shepherd.
 ;;
@@ -810,13 +811,19 @@ given USER and/or GROUP to run COMMAND."
 
 ;;; Perform actions with services:
 
-;; Call PROC once for each registered service.
+(define (lookup-canonical-service name services)
+  "Return service with canonical NAME from SERVICES list.
+Return #f if service is not found."
+  (find (lambda (service)
+          (eq? name (canonical-name service)))
+        services))
+
 (define (for-each-service proc)
-  (hash-fold (lambda (key value unused)
-	       (and (eq? key (canonical-name (car value)))
-		    (proc (car value))))
-	     #f ;; Unused
-	     %services))
+  "Call PROC for each registered service."
+  (hash-for-each (lambda (name services)
+                   (and=> (lookup-canonical-service name services)
+                          proc))
+                 %services))
 
 (define (service-list)
   "Return the list of services currently defined."
-- 
2.6.3