; let’s make inc and dec derivable
(make-update-deriver 'inc)
(make-update-deriver 'dec)

(deftype T [x Int y Int z Int])
(derive T inc)
(derive T dec)
(derive T zero)
(derive T str)
(derive T = eq)

(defn main []
  (do
    (println* &(T.inc (T.init 1 2 3)))
    (println* &(T.dec (T.init 1 2 3)))
    (println* &(T.zero))
    (println* (= &(T.init 1 2 3) &(T.init 1 2 3)))
    (println* (= &(T.init 1 2 3) &(T.init 1 3 2)))))