+let rec minimize_qtree q =
+ if q.id != -1 then q
+ else
+ try
+ QTreeHash.find mini_table q
+ with Not_found ->
+ let mdesc =
+ match q.desc with
+ (Start | Dom | Tag _) as d -> d
+ | Binop(op,q1,q2) -> let mq1 = minimize_qtree q1 in
+ let mq2 = minimize_qtree q2 in
+ Binop(op,mq1,mq2)
+ | Axis(a,q1) -> let mq1 = minimize_qtree q1 in
+ Axis(a,mq1)
+ in
+ q.desc <- mdesc;
+ q.hash <- QTree.hash q;
+ q.id <- !mini_id;
+ incr mini_id;
+ QTreeHash.add mini_table q q;
+ q
+
+
+
+let rec eval_qtree tree start q =