ref: 02efc3a7d15eb97ec7b80be68474d112f65493c8
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") }