anchor.diff:        (make-instance 'kell :name name))))
   
   (defmethod print-object ((obj kell) stream)
  -  (format stream "[~s ~s~:[ ~s~;~]]"
  +  (format stream "[~a ~s~:[ ~s~;~]]"
             (name obj) (state obj)
             (eql (continuation obj) null) (continuation obj)))
   
  
positive.code:      :names (if (consp ',names) ',names (list ',names)) :abstraction ,process))
  
  (defmethod print-object ((obj restriction) stream)
    (format stream "(new ~s ~s)" (names obj) (abstraction obj)))
  
  (defclass message (process)
    ((name :initarg :name :accessor name :type name)
  
negative.code:                  :accessor continuation)))
  
  (defmethod print-object ((obj message) stream)
    (format stream "{~a~:[ ~s~:[ ~s~;~]~;~]}"
            (name obj)
            (and (eql (argument obj) null)
                 (eql (continuation obj) null))
  