class Note does Callable { has $.note; multi method CALL-ME(UInt $oct) { "$!note$oct" } multi method CALL-ME { self } } my &G = Note.new: :note<G>; sub infix:<♯>(Note $note, UInt $oct) { $note.clone(:note($note.note ~ "#")).($oct) } sub infix:<♭>(Note $note, UInt $oct) { $note.clone(:note($note.note ~ "b")).($oct) } say G 4; say G♯ 4; say G♭ 4;