ref: 038b1d6b1e2f30d0cc5168ee342b8b422b7d4818
dir: /test/uconinit.myr/
use std
type u = union
`A
`B
`C int
;;
const a = [`A, `B, `C 123]
const main = {
for v : a
match v
| `A: std.put("A ")
| `B: std.put("B ")
| `C x: std.put("C {}\n", x)
;;
;;
std.put("\n")
}