+let compare u1 u2 =
+ let su1 = string_of_uri u1 in
+ let su2 = string_of_uri u2 in
+ Pervasives.compare su1 su2
+
+module OrderedUri =
+struct
+ type t = uri
+ let compare = compare (* the one above, not Pervasives.compare *)
+end
+
+module UriSet = Set.Make (OrderedUri)
+