Spice up the example a little

os-big-bang-example.rkt

@@ -1,5 +1,6 @@
 #lang racket/base
 
+(require racket/match)
 (require racket/port)
 (require "os-big-bang.rkt")
 
@@ -40,8 +41,13 @@
 	     (subscribe 'display-driver display-driver-handler)
 	     (subscribe 'read-line-driver read-line-driver-handler)
 	     (tick-driver 'ticker 1000)
-	     (send-message `(display "Hello! Enter your name:\n"))
-	     (send-message `(request read-name read-line))
+	     (send-message 'greet-loop)
+	     (subscribe 'greet-loop-handler
+			(message-handlers w
+			 ['greet-loop
+			  (transition w
+				      (send-message `(display "Hello! Enter your name:\n"))
+				      (send-message `(request read-name read-line)))]))
 	     (subscribe 'ticker-handler
 			(message-handlers w
 			 [`(tick ,counter ,_)
@@ -50,12 +56,16 @@
 				       `(display ,(string-append "TICK "
 								 (number->string counter)
 								 "\n"))))]))
-	     (subscribe 'greet
+	     (subscribe 'read-line-result-handler
 			(message-handlers w
+			 [`(reply read-name ,(== eof))
+			  (transition w
+				      (send-message `(display "Goodbye!\n")))]
 			 [`(reply read-name ,name)
 			  (transition w
 				      (send-message `(display "Hello, "))
 				      (send-message `(display ,name))
 				      (send-message `(display "!\n"))
 				      (unsubscribe 'ticker)
+				      (send-message 'greet-loop)
 				      )])))