ref: 3a496c143eb8aad32c03c7067c54807256949c97
dir: /test/uconinit.myr/
use std
type u = union
	`A
	`B
	`C int
;;
const a = [`A, `B, `C 123]
const main = {
	for v in a
		match v
		| `A:	std.put("A ")
		| `B:	std.put("B ")
		| `C x:	std.put("C {}\n", x)
		;;
	;;
	std.put("\n")
}