anchor.diff:    (fmt "An error of type TYPE-ERROR might be signaled if SEQUENCE is not a~@
           proper sequence."))
   
  -(defparameter *error-bounding-indexes*
  +(defparameter *error-not-valid-index*
  +  (fmt "An error of type TYPE-ERROR is signaled if INDEX is not a~@
  +        valid sequence index for SEQUENCE"))
  +
  +(defparameter *maybe-error-bounding-indexes*
     (fmt "An error might be signaled if START and END are not valid bounding~@
  +	index designators for SEQUENCE, which means that 0 <= START <= L, and~@
  +	either END is NIL or 0 <= END <= L where L is the length of SEQUENCE."))
  +
  +(defparameter *definitely-error-bounding-indexes*
  +  (fmt "An error is signaled if START and END are not valid bounding~@
   	index designators for SEQUENCE, which means that 0 <= START <= L, and~@
   	either END is NIL or 0 <= END <= L where L is the length of SEQUENCE."))
   
  
positive.code: 	     *predicate-sequence* *key* *bounding-indexes* *from-end*
  	     *satisfy-a-one-argument-negative-test*
  	     *error-not-proper-sequence*
  	     *error-bounding-indexes*))
  
  (defparameter *remove-description*
    (fmt "Returns a sequence that is like SEQUENCE, except that the elements in~@
  
negative.code:   (defun fmt (&rest args)
      (apply #'format nil args)))
  
  (defparameter *sequence*
    (fmt "SEQUENCE is a proper sequence"))
  
  (defparameter *index*
    (fmt "INDEX is a valid sequence index for SEQUENCE"))
  
  (defparameter *item-sequence*
    (fmt "ITEM is any object, and SEQUENCE is a proper sequence."))
  
  