multi infix:<+> ($a, $b) is default { given ($a, $b) { when (Iterable, Iterable) { $a «+» $b } when (Iterable, Any) { $a.map(* + $b) } when (Any, Iterable) { $b.map(* + $a) } default { $a + $b } } } say (1, 2, 3) + 5; say 5 + (4, 5, 6); say (1, 2, 3) + (4, 5, 6);