val fold : (elt -> 'a -> 'a) -> t -> 'a -> 'a
val map : (elt -> elt) -> t -> t
val length : t -> int
- val merge : bool -> bool -> bool -> bool -> elt -> t -> t -> t
+ val merge : (bool*bool*bool*bool)-> elt -> t -> t -> t
end
module IdSet : ResultSet