;;;; A pointer and an untagged union take a byte fill. The union is filled
;;;; over its whole size, so its widest member reads back every byte; the
;;;; pointer is read back through a union that overlays it with a u64, since
;;;; there is no other way to see an address as a number.
(defunion U [a u32  b [8 u8]])
(defunion W [p (Ptr i32)  n u64])

(defn main [] i32
  (let [u (array 1 U)]
    (set u (filled 0xAB))
    (println (.a (at u 0)))                   ; 2880154539
    (println (at (.b (at u 0)) 7)))           ; 171
  (let [w (array 1 W)]
    (set (.p (at w 0)) (dead-beef))
    (println (.n (at w 0)))                   ; 17275436393656397278
    (set (at w 0) (filled 0x01))
    (println (.n (at w 0))))                  ; 72340172838076673
  0)