#lang prospect version of example

prospect/examples/example-lang.rkt

@@ -0,0 +1,70 @@
+#lang prospect
+
+(require (only-in racket/port read-line-evt))
+(require "../drivers/timer.rkt")
+
+(define (quasi-spy e s)
+  (printf "----------------------------------------\n")
+  (printf "QUASI-SPY:\n")
+  (match e
+    [(? patch? p) (pretty-print-patch p)]
+    [other
+     (write other)
+     (newline)])
+  (printf "========================================\n")
+  #f)
+(spawn quasi-spy (void) (sub ?))
+
+(define (r e s)
+  (match e
+    [(message body) (transition s (message (at-meta `(print (got ,body)))))]
+    [_ #f]))
+
+(define (b e n)
+  (match e
+    [#f (if (< n 10)
+	    (transition (+ n 1) (message `(hello ,n)))
+	    #f)]
+    [_ #f]))
+
+(spawn-world (spawn r (void) (sub ?))
+             (spawn b 0))
+
+(define (echoer e s)
+  (match e
+    [(message (at-meta (external-event _ (list (? eof-object?)))))
+     (transition s (quit))]
+    [(message (at-meta (external-event _ (list line))))
+     (transition s (message `(print (got-line ,line))))]
+    [_ #f]))
+
+(spawn echoer (void)
+       (sub (external-event (read-line-evt (current-input-port) 'any) ?) #:meta-level 1))
+
+(define (ticker e s)
+  (match e
+    [(? patch? p)
+     (printf "TICKER PATCH RECEIVED:\n")
+     (pretty-print-patch p)
+     #f]
+    [(message (timer-expired 'tick now))
+     (printf "TICK ~v\n" now)
+     (transition (+ s 1) (if (< s 3)
+			     (message (set-timer 'tick 1000 'relative))
+			     (quit)))]
+    [_ #f]))
+
+(spawn-timer-driver)
+(message (set-timer 'tick 1000 'relative))
+(spawn ticker 1
+       (sub (observe (set-timer ? ? ?)))
+       (sub (timer-expired 'tick ?)))
+
+(define (printer e s)
+  (match e
+    [(message (list 'print v))
+     (log-info "PRINTER: ~a" v)
+     #f]
+    [_ #f]))
+
+(spawn printer (void) (sub `(print ,?)))