Concision.

os.rkt

@@ -174,9 +174,7 @@
 	 (vm-suspensions state)))
 
 (define (run-runnables state)
-  (foldl (lambda (r state)
-	   (match-define (runnable process-state k) r)
-	   (perform-transition (k process-state) state))
+  (foldl (lambda (r state) (perform-transition ((runnable-k r) (runnable-state r)) state))
 	 (struct-copy vm state [pending-processes (make-queue)])
 	 (queue->list (vm-pending-processes state))))
 
@@ -286,22 +284,11 @@
 
 ;;---------------------------------------------------------------------------
 
-(define (nested-vm-inert? transition)
-  (match transition
-    [(kernel-mode-transition (subscription (vm _
-					       (? queue-empty?)
-					       (? queue-empty?)
-					       (? queue-empty?)
-					       _)
-					   #f
-					   '()
-					   '())
-			     _
-			     _
-			     '())
-     ;; No pending-messages within the nested VM, so no internal
-     ;; activity is possible, and furthermore it is not waiting for
-     ;; any outside messages.
+(define (nested-vm-inert? sub)
+  (match sub
+    [(subscription (vm _ (? queue-empty?) (? queue-empty?) (? queue-empty?) _) #f '() '())
+     ;; Inert iff not waiting for any messages or metamessages, and
+     ;; with no internal work left to do.
      #t]
     [_ #f]))
 
@@ -313,7 +300,7 @@
 ;; Runs its argument VM until it becomes (provably) inert.
 (define (ground-vm pattern-predicate boot)
   (let loop ((transition (run-vm (make-vm pattern-predicate boot))))
-    (when (not (nested-vm-inert? transition))
+    (when (not (nested-vm-inert? (kernel-mode-transition-subscription transition)))
       (match transition
 	[(kernel-mode-transition (subscription new-state
 					       polling-k