V.I
val (<$>) : ('a -> 'b) -> 'a Arr.Alt.t -> 'b Arr.Alt.t
val (<@>) : 'a Arr.Alt.t -> ('a -> 'b) -> 'b Arr.Alt.t
val (<|>) : 'a Arr.Alt.t -> 'a Arr.Alt.t -> 'a Arr.Alt.t