anchor.diff:  	     supertypes)
   	(values t t)))))
   
  +(define-presentation-method present ((object list) (type sequence-enumerated)
  +				     stream
  +				     (view textual-view)
  +				     &key acceptably for-context-type)
  +  (declare (ignore for-context-type))
  +  (loop for tail on object
  +	for (obj) = tail
  +	for obj-type in types
  +	do (progn
  +	     (present obj obj-type
  +			:stream stream :view view
  +			:acceptably acceptably
  +			:sensitive nil)
  +	     (when (cdr tail)
  +	       (if acceptably
  +		   (princ separator stream)
  +		   (terpri stream))))))
  +
  +(define-presentation-method present ((object vector) (type sequence-enumerated)
  +				     stream
  +				     (view textual-view)
  +				     &key acceptably for-context-type)
  +  (declare (ignore for-context-type))
  +  (loop for i from 0 below (length object)
  +	for obj = (aref object i)
  +	for obj-type in types
  +	do (progn
  +	     (present obj obj-type
  +			:stream stream :view view
  +			:acceptably acceptably
  +			:sensitive nil)
  +	     (when (< i (1- (length object)))
  +	       (if acceptably
  +		   (princ separator stream)
  +		   (terpri stream))))))
  +
   (define-presentation-type or (&rest types)
     :parameters-are-types t)
   
  
positive.code:        (typep (realpart object) type)
         (typep (imagpart object) type)))
  
  
  (define-presentation-type real (&optional low high) :options ((base 10) radix)
  			  :inherit-from 'number)
  
negative.code: 
  (define-presentation-type expression ())
  
  (define-presentation-method present (object (type expression)
  				     stream
  				     (view textual-view)
  				     &key acceptably for-context-type)
    (declare (ignore for-context-type))
    (let ((*print-readably* acceptably))
      (princ object stream)))
  
  (define-presentation-type form ()
    :inherit-from `expression)
  
  