val compteur : int ref
(**the counter of nodes*)

val element_by_tag : Naive_tree.t -> QNameSet.t -> Tree.NodeKind.t -> Bitvector.t
(** [element_by_tag t tag] returns all the nodes whose tag equal to [tag] in the tree [t]. *)

val compile_single_path : Xpath.Ast.single_path -> Table.query_tree 
(** il y a un cycle si on met la definition de query_tree dans le fichier [Query_tree.ml]
    [compile_single_path spath] returns un query_tree built with [spath]
*)

val compile_xpath : Xpath.Ast.path -> Table.query_tree 
(** [compile_xpath path] returns un query_tree built with [xpath]
*)

val minimize_qtree : Table.query_tree -> Table.query_tree
(** [minimize_qtree q] returns the minimum query_tree of [q]
    [q] query_tree
*)

val eval_qtree : Naive_tree.t -> Bitvector.t ->Table.query_tree -> Bitvector.t
(** [eval_qtree tree start q] returns the set of nodes that evaluate by the query_tree [q].
    [start] the set of nodes departing.
    [q] query_tree
*)