ref: c08505fb46fd8cdfee6b6f425709e5bc536f6a75
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")
}