anchor.diff:  			:lambda-list '(new-value sheep)
   			:participants (list =t= sheep)
   			:body `(setf (property-value sheep ',prop-name) new-value)
  -			:function (eval (make-message-lambda '(new-value sheep) 
  +			:function (eval (make-message-lambda writer
  +							     '(new-value sheep) 
   							     `((setf (property-value sheep ',prop-name)
   								     new-value)))))))
   
  
positive.code: 			:lambda-list '(sheep)
  			:participants (list sheep)
  			:body `(property-value sheep ',prop-name)
  			:function (eval (make-message-lambda '(sheep) 
  							     `((property-value sheep ',prop-name)))))))
  
  (defun add-writers-to-sheep (writers prop-name sheep)
  
negative.code: 			      args)
  			  (cdr next-messages))))
  	  (declare (ignorable #'next-message-p #'call-next-message))
  	  (block ,(if (listp name)
  		      (cadr name)
  		      name)
  	    (apply
  	    (lambda ,(eval (extract-lambda-list lambda-list))
  	      ,@body) args)))))
  
  