From 49483f71381ad32cdbe81b1c8ed2cc023329cc18 Mon Sep 17 00:00:00 2001
From: Ludovic Courtès <ludo@gnu.org>
Date: Wed, 8 Nov 2017 13:26:08 +0100
Subject: services: Add 'lookup-service-types'.

* gnu/services.scm (lookup-service-types): New procedure.
* tests/services.scm ("lookup-service-types"): New test.
---
 gnu/services.scm | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'gnu/services.scm')

diff --git a/gnu/services.scm b/gnu/services.scm
index df1bedeb9b..016ff08e0b 100644
--- a/gnu/services.scm
+++ b/gnu/services.scm
@@ -55,6 +55,7 @@
 
             %service-type-path
             fold-service-types
+            lookup-service-types
 
             service
             service?
@@ -192,6 +193,16 @@ is used as the initial value of RESULT."
                                 seed
                                 modules))
 
+(define lookup-service-types
+  (let ((table
+         (delay (fold-service-types (lambda (type result)
+                                      (vhash-consq (service-type-name type)
+                                                   type result))
+                                    vlist-null))))
+    (lambda (name)
+      "Return the list of services with the given NAME (a symbol)."
+      (vhash-foldq* cons '() name (force table)))))
+
 ;; Services of a given type.
 (define-record-type <service>
   (make-service type value)
-- 
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