anchor.diff:  (defun rassoc-eq-key (item alist key)
     (loop for element in alist
           when (and (not (null element))
  -		  (eq (funcall key (cdr element)) item))
  +		  (eq item (funcall key (cdr element))))
             return element))
     
   ;;; Special version when test is eql and key is given.
  
positive.code: (defun rassoc-not-eq-key (item alist key)
    (loop for element in alist
          when (and (not (null element))
  		  (not (eq (funcall key (cdr element)) item)))
            return element))
    
  ;;; Special version when test-not is eql and key is given.
  
negative.code: (defun assoc-eq-key (item alist key)
    (loop for element in alist
          when (and (not (null element))
  		  (eq item (funcall key (car element))))
            return element))
    
  ;;; Special version when test is eql and key is given.
  