val nth_opt : 'a t -> integer -> 'a optionval map : ('a -> 'b) -> 'a t -> 'b tval mapi : (integer -> 'a -> 'b) -> 'a t -> 'b tval fold_left : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'aval fold_right : ('b -> 'a -> 'a) -> 'b t -> 'a -> 'aval map2 : ('a -> 'b -> 'c) -> 'a t -> 'b t -> 'c tval for_all : ('a -> bool) -> 'a t -> boolval _exists : ('a -> bool) -> 'a t -> boolval for_all2 : ('a -> 'b -> bool) -> 'a t -> 'b t -> boolval _exists2 : ('a -> 'b -> bool) -> 'a t -> 'b t -> boolval mem : 'a -> 'a t -> bool