module type Basic = sig .. end
sig
end
type '_ t
'_
val foldl : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'a
('a -> 'b -> 'a) -> 'a -> 'b t -> 'a
val foldr : ('a -> (unit -> 'b) -> 'b) -> (unit -> 'b) -> 'a t -> 'b
('a -> (unit -> 'b) -> 'b) -> (unit -> 'b) -> 'a t -> 'b