(push)
(datatype Math
  (Num i64))

(sort MathVec (Vec Math))

(let v1 (vec-of (Num 1) (Num 2)))
(let v2 (vec-of (Num 2) (Num 2)))

(union (Num 1) (Num 2))

(check (= v1 v2))

(function MyVec (MathVec) Math)

(MyVec v1)

(check (MyVec v2))

(check (= (MyVec v1) (MyVec v2)))

(let v3 (vec-of (Num 4) (Num 5)))

(union (Num 4) (Num 6))
(union (Num 5) (Num 7))

;; We don't have any (MyVec v3) yet
(fail (check (= (MyVec v3) (MyVec (vec-of (Num 6) (Num 7))))))

(MyVec v3)
(check (= (MyVec v3) (MyVec (vec-of (Num 6) (Num 7)))))

(pop)

(push)

(datatype Math
  (Num i64))

(sort MathVec (Vec Math))


(let v1 (vec-of (Num 1) (Num 2)))
(let v2 (vec-of (Num 2) (Num 2)))

(union (Num 1) (Num 2))

(function MyVec (MathVec) Math)

;; make a reference to v1
(MyVec v1)

(extract (MyVec v1))

;; rebuilding creates (MyVec v2)
(check (= (MyVec v1) (MyVec v2)))
(pop)

(push)
(datatype Math
  (Add i64 i64)
  (Expensive :cost 100))

(sort MathVec (Vec Math))

(let myvec (vec-of (Expensive)))
(let cheapvec (vec-of (Add 1 2)))

(function VecContainer (MathVec) Math)

(let myvecontainer (VecContainer cheapvec))


(union myvecontainer (Expensive))

;; (vec-push (vec-empty) (VecContainer (vec-push (vec-empty) (Add 1 2))))
;; should have cost 4
(extract myvec 0)

(pop)