anchor.diff:                              (cons (rec (car symbol))
                                     (rec (cdr symbol)))))))))
         (rec tree))))
  +
  +
   
   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   ;; HIGHER ORDER FUNCTIONS ;;
  
positive.code:   (or (null symbol)
        (eq symbol :epsilon)
        (equal symbol '(:epsilon))))
  
  ;;;;;;;;;
  ;; I/O ;;
  
negative.code:                   b))
         a))
  
  (defun multiple-value-reduce (function sequence &key initial-value-list)
    (let ((result initial-value-list))
      (map nil
  