(defmacro defun (name params body)
   (setq name (lambda params body)))

(defmacro def (name params body)
   (setq name (lambda params body)))
 
(defmacro or (a b)
   (if a a b))
 
(defmacro and (a b)
   (if a b nil))
 
(defun <= (x y)
   (or (< x y) (eq x y)))
 
(defun > (x y)
   (< y x))
 
(defun >= (x y)
   (<= y x))
 
(defun - (x y)
   (+ x (neg y)))
 
(defun nullp (x)
   (eq x nil))

(defmacro set (var val)
   (setq var val))

(defmacro head (cell)
   (car cell))

(defmacro tail (cell)
   (cdr cell))