diff --git a/core/actor.lisp b/core/actor.lisp
index b86d40a..fdf98dd 100644
--- a/core/actor.lisp
+++ b/core/actor.lisp
@@ -47,12 +47,18 @@
 (defun stop (mb)
   (send mb +quit-message+))
 
+(defvar *self* nil)
+
 (defgeneric ac-loop (tsk bhv)
   (:method ((tsk async:mailbox) bhv)
-    (let ((msg (async:rcv tsk)))
+    (let ((*self* tsk)
+          (msg (async:rcv tsk)))
       (unless (eq (content msg) +quit-message+)
         (ac-loop tsk (or (funcall bhv msg) bhv))))))
 
+(defgeneric set-bhv (tsk bhv)
+  (:method ((tsk async:mailbox) bhv)))
+ 
 ;;;; the core (classical, i.e. Hewitt) actor API
 
 (defun create (bhv)
@@ -65,8 +71,9 @@
     ;(util:lgi msg)
     (async:snd tsk msg)))
 
-(defgeneric become (tsk bhv)
-  (:method ((tsk async:mailbox) bhv) bhv))
+(defun become (bhv)
+  (set-bhv *self* bhv)
+  bhv)
 
 ;;;; handling restartable tasks
 
@@ -76,9 +83,9 @@
     (if ok
       (if (eq (content msg) +quit-message+)
         (progn (async:set-status tsk :stopped) nil)
-        (progn 
+        (let ((*self* tsk)) 
           (async:set-status tsk :running)
-          (ac-vloop tsk (or (funcall bhv msg) bhv))))
+          (ac-loop tsk (or (funcall bhv msg) bhv))))
       (progn (async:set-status tsk :suspended) bhv))))
 
 (defmethod send ((tsk async:restartable-task) msg)
@@ -94,9 +101,8 @@
         tsk (lambda () (ac-loop tsk (async:behavior tsk)))))
     (async:set-status :running)))
 
-(defmethod become ((tsk async:task) bhv)
-  (setf (async:behavior tsk) bhv)
-  bhv)
+(defmethod set-bhv ((tsk async:task) bhv)
+  (setf (async:behavior tsk) bhv))
  
  ;;;; predefined behaviors
 
@@ -114,7 +120,7 @@
   (lambda (msg)
     ;(format t "calc ~a ~a~%" val (content msg))
     (destructuring-bind (fn &optional param) (content msg)
-      (funcall fn msg val param))))
+      (become (funcall fn msg val param)))))
 
 (defun plus (msg val param)
   (calculator (+ val param))) 
diff --git a/util/async.lisp b/util/async.lisp
index 50ff129..724b750 100644
--- a/util/async.lisp
+++ b/util/async.lisp
@@ -4,7 +4,7 @@
   (:use :common-lisp)
   (:local-nicknames (:lp :lparallel)
                     (:lpq :lparallel.queue))
-  (:export #:init #:finish #:make-ch #:make-mb #:make-task #:rcv #:try-rcv #:snd 
+  (:export #:init #:finish #:make-mb #:make-task #:rcv #:try-rcv #:snd 
            #:mailbox #:task #:restartable-task #:behavior #:get-status #:set-status
            #:submit-task #:receive-result #:try-receive-result))