Currently, the HAppS.DBMS lib requires the user to provide a Show instance for their table types. An example might be: instance (Show item) => Show (MyTable item) where showsPrec d table = showsPrec d $ Set.toList $ myTableSet table But the Table class itself defines a toSet function so I think I should be able to do this once for all Table instances: instance (Show item,Ord item, Table table item p) => Show (table item) where showsPrec d table = showsPrec d $ Set.toList $ toSet table But I get an error telling me I am overlapping with Show [a]. Since [] is not an instance of Table, I don't see why there should be an overlap. -Alex- ______________________________________________________________ S. Alexander Jacobson tel:917-770-6565 http://alexjacobson.com