val empty : 'a tval fold : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'aval fold_while : ('a -> 'b -> 'a * [ `Stop | `Continue ]) -> 'a -> 'b t -> 'aval iter : ('a -> unit) -> 'a t -> unitval to_queue : 'a Stdlib.Queue.t -> 'a t -> unitval of_queue : 'a Stdlib.Queue.t -> 'a tval to_list : 'a t -> 'a listval of_list : 'a list -> 'a t