]> Bonjour, > After your remarks and Brian's, I'm starting to wonder if it is > possible at all to do what I want. Maybe I should be looking for an > impossibility proof instead... Patricia sets seem to be what you are looking for. (1). Efficient usual operations (lookup, insertion, union) (2). Structural equality Their only problem is that they cannot handle polymorphic orderable types but only integers... Hash the data, use this key to insert it in a patricia map and solve the collisions by chaining in an ordered list (with the polymorphic [compare] function). (1) and (2) still hold under usual hypothesis on the rate of collisions. A few changes to JCF's implementation should be enough. Diego Olivier ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners