anchor.diff:  
   (defmethod stream-draw-ast ((ast function-ast) stream)
     (format stream "   ~a [label = \"function\"];~%"
  -	  (id ast))
  -  (stream-draw-ast (body-ast ast) stream)
  -  (format stream "   ~a -> ~a~%"
  -	  (id ast)
  -	  (id (body-ast ast))))
  +	  (id ast)))
   
   (defmethod body-ast ((ast function-ast))
     (first (children ast)))
  
positive.code: 
  (defmethod stream-draw-ast ((ast store-contents-ast) stream)
    (format stream "   ~a [label = \"store-contents\"];~%"
  	  (id ast))
    (stream-draw-ast (form-ast ast) stream)
    (format stream "   ~a -> ~a~%"
  	  (id ast)
  	  (id (form-ast ast)))
    (stream-draw-ast (offset-ast ast) stream)
    (format stream "   ~a -> ~a~%"
  	  (id ast)
  	  (id (offset-ast ast)))
    (stream-draw-ast (value-ast ast) stream)
    (format stream "   ~a -> ~a~%"
  	  (id ast)
  	  (id (value-ast ast))))
  
  (defmethod form-ast ((ast store-contents-ast))
    (first (children ast)))
  
negative.code: 
  (defmethod stream-draw-ast ((ast neg-ast) stream)
    (format stream "   ~a [label = \"neg\"];~%"
  	  (id ast)))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  