; Test that can run rule matching on rational

(datatype Pretty
    (pretty-str String)
    (pretty-rational Rational))

; This will fail with `Unbound variable x in primitive computation` currently:
; (rewrite (pretty-rational (rational x y)) (pretty-str (+ (to-string x) "/" (to-string y))))

(rewrite (pretty-rational r) (pretty-str (+ (to-string (numer r)) "/" (to-string (denom r)))))

(let z (pretty-rational (rational 1 2)))
(run 1)
(check (= z (pretty-str "1/2")))