val fold: (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
val filter: (key -> 'a -> bool) -> 'a t -> 'a t
val bindings: 'a t -> (key * 'a) list
+
+ (* This is not the normal Map.merge function. *)
+ val merge : 'a t -> 'a t -> 'a t
end
(** Location where we parsed from $loc = $startpos, $endpos *)