anchor.diff:      (let ((key-iterator (make-hash-key-iterator h)))
         (lambda ()
           (let ((key (funcall key-iterator)))
  -          (cons key (gethash key h)))))))
  +          (cons key (gethash key h))))))
  +
  +  (:method ((s stream))
  +    (etypecase (stream-element-type s)
  +      (character (make-character-stream-iterator s))
  +      (integer   (make-byte-stream-iterator s)))))
   
   (defun make-hash-key-iterator (h)
     (declare (hash-table h))
  
positive.code:   (let ((vals (loop for v being the hash-values of h
                    collect v)))
      (get-iterator vals)))
  
  (defun inext (iterator &rest args)
    "Return the next value of an iterator and whether or not an actual value was
  
negative.code:   (:export #:get-iterator
             #:make-hash-key-iterator
             #:make-hash-value-iterator
             #:make-character-stream-iterator
             #:make-byte-stream-iterator
             #:make-line-iterator
             #:iteration-ended #:end-iteration
             #:do-iterator #:do-iterable
             #:inext
  