;; Because I don't (yet) have syntax for varargs, the body must be passed
;; to defun as a list of sexprs.
(set! defun!
      (nlambda
       form
       (cond ((symbolp (car form))
         (set (car form) (apply lambda (cdr form))))
         (t nil))))

(defun! square (x) (* x x))

(set! defsp!
      (nlambda
       form
       (cond (symbolp (car form))
         (set! (car form) (apply nlambda (cdr form))))))

(defsp! cube (x) ((* x x x)))

(set! p 5)

(square 5) ;; should work

(square p) ;; should work

(cube 5) ;; should work

(cube p) ;; should fail: unbound symbol