; (the-op 3 - 2 - 4)
; ==> -3

(defmacro the-op (&body body)
  `(if ',body (op ,@(reverse body))))

(defmacro op (x &optional y &rest z)
  `(if ,y (if ',z (op (,y (op ,@z) ,x)) (,y ,x)) ,x))

(defmacro the-op (&body body)
  `(if ',body (op ,@(reverse body))))

(defmacro op (x &optional y &rest z)
  (with-gensyms (a b c)
    `(let ((,a ,x)
 	   (,b ,y)
	   (,c ',z))
       (if ,b (if ',z (op (,b (op ,@c) ,a)) (,b ,a)) ,a))))


;; from practical common lisp
(defmacro with-gensyms ((&rest names) &body body)
  `(let ,(loop for n in names collect `(,n (gensym)))
     ,@body))