Interleaved processing example.

[actors.git] / actors.scm

diff --git a/actors.scm b/actors.scm
index b8e52a8..8a581b9 100644 (file)
--- a/actors.scm
+++ b/actors.scm
@@ -1,5 +1,7 @@
 (import srfi-69 matchable)
 
+(define trace-enabled #t)
+
 ;;;
 ;;; Actor creation
 ;;;
@@ -13,7 +15,7 @@
 (define next-actor-address 1)
 
 (define (make-actor behaviour)
-  (make-actor-with-id next-actor-address behaviour)
+  (make-actor-with-address next-actor-address behaviour)
   (let ((address next-actor-address))
     (set! next-actor-address (+ next-actor-address 1))
     address))
@@ -23,9 +25,17 @@
 ;;;
 
 (define (dispatch-message address message)
-  (let ((behaviour (hash-table-ref actor-table address)))
-    (unless (null? behaviour)
-      ((hash-table-ref actor-table address)))) message)
+  (if trace-enabled
+      (print "Dispatching message " message " to " address))
+  (let ((behaviour (hash-table-ref/default actor-table address '())))
+    (if (null? behaviour)
+        (print "Warning: discarded message " message " to unknown actor " address)
+        (let ((value (apply behaviour (cons address message))))
+          (match value
+            ('done (hash-table-delete! actor-table address))
+            ('sleep 'do-nothing)
+            (else
+             hash-table-set! actor-table address value))))))
 
 ;;;
 ;;; FIFO queue implementation
@@ -89,17 +99,45 @@
       '()
       (fifo-pop message-queue)))
 
-(define (send-message actor message)
+(define (send-message actor . message)
+  (if trace-enabled
+      (print "Queued message " message " to " actor))
   (fifo-push message-queue (cons actor message)))
 
-(define (run)
+(define (process-next-message)
   (let ((addressed-msg (next-addressed-msg)))
-    (if (null? msg)
-        'done
-        (begin
-          (apply dispatch-message addressed-msg)
-          (run)))))
+    (if (null? addressed-msg)
+        '()
+        (let ((address (car addressed-msg))
+              (message (cdr addressed-msg)))
+          (dispatch-message address message)))))
+
+(define (run)
+  (unless (null? (process-next-message))
+    (run)))
+
+(define (send-and-run actor . message)
+  (apply send-message (cons actor message))
+  (run))
 
 ;;;
-;;; Send
+;;; Testing
 ;;;
+
+(define factorial
+  (make-actor-with-address 'factorial
+   (lambda (self customer . message)
+     (match message
+       ((n) (send-message self customer n 1) 'sleep)
+       ((0 acc) (send-message customer acc) 'done)
+       ((n acc) (send-message self customer (- n 1) (* acc n)) 'sleep)))))
+
+(define println
+  (make-actor-with-address 'println
+   (lambda (self . message)
+     (apply print message)
+     'sleep)))
+
+(send-message factorial println 5)
+(send-message factorial println 7)
+(run)