[use keysSet to turn IdMap's to IdSet's.
John Meacham <john@repetae.net>**20080222125426] hunk ./Name/Id.hs 18
+    idToInt,
hunk ./Name/Id.hs 83
-idMapToIdSet (IdMap im) = IdSet $ IS.fromDistinctAscList (IM.keys im)
+idMapToIdSet (IdMap im) = IdSet $ (IM.keysSet im)