ref: 03aaebc565cf8b99b2babb03120998ab3f5a6d31
dir: /test/matchunion_sl.myr/
use std /* checks pattern matching on unions with arguments. exits with 42. */ type u = union `Int int `Str byte[:] `Nil ;; const main = { var v v = `Str "foo" match v | `Int 127: std.exit(42) | `Str s: std.put("%s\n", s) | `Nil: ;; }