diff --git a/simulator-prims.rkt b/simulator-prims.rkt
index edc3752..0755bef 100644
--- a/simulator-prims.rkt
+++ b/simulator-prims.rkt
@@ -32,5 +32,9 @@
 (provide lookup-primitive)
 (define lookup-primitive (make-lookup #:functions (+ - * / = < <= > >= cons list car cdr
                                                      sub1
-                                                     display newline displayln)
+                                                     display newline displayln
+                                                     not
+                                                     pair?
+                                                     eq?
+                                                     null?)
                                       #:constants (null pi e)))
diff --git a/test-compiler.rkt b/test-compiler.rkt
index 0f140c5..ccd9f71 100644
--- a/test-compiler.rkt
+++ b/test-compiler.rkt
@@ -206,6 +206,7 @@
         (f 1000))
       #:stack-limit 8)
 
+
 ;; And from experimental testing, anything below 7 will break.
 (test/exn (begin (define (f x acc)
                    (if (= x 0)
@@ -233,6 +234,42 @@
       7)
       
 
+;; deriv
+(test (begin (define (deriv-aux a) (list '/ (deriv a) a))
+             (define (map f l)
+               (if (null? l)
+                   l
+                   (cons (f (car l))
+                         (map f (cdr l)))))
+             (define (deriv a)
+               (if (not (pair? a))
+                   (if (eq? a 'x) 1  0)
+                   (if (eq? (car a) '+)
+                       (cons '+ (map deriv (cdr a)))
+                       (if (eq? (car a) '-)
+                           (cons '- (map deriv
+                                         (cdr a)))
+                           (if (eq? (car a) '*)
+                               (list '*
+                                     a
+                                     (cons '+ (map deriv-aux (cdr a))))
+                               (if (eq? (car a) '/)
+                                   (list '-
+                                         (list '/
+                                               (deriv (cadr a))
+                                               (caddr a))
+                                         (list '/
+                                               (cadr a)
+                                               (list '*
+                                                     (caddr a)
+                                                     (caddr a)
+                                                     (deriv (caddr a)))))
+                                   'error))))))
+             (deriv '(+ (* 3 x x) (* a x x) (* b x) 5)))
+      '(+ (* (* 3 x x) (+ (/ 0 3) (/ 1 x) (/ 1 x)))
+          (* (* a x x) (+ (/ 0 a) (/ 1 x) (/ 1 x)))
+          (* (* b x) (+ (/ 0 b) (/ 1 x)))
+          0))
 
 
 ;(simulate (compile (parse '42) 'val 'next))