module Ast :
sig
  type path = Absolute of step list | AbsoluteDoS of step list| Relative of step list
  and step = axis * test * predicate
  and axis = Self | Attribute | Child | Descendant | DescendantOrSelf | FollowingSibling
	     | Parent | Ancestor | AncestorOrSelf |PrecedingSibling | Preceding | Following
  and test =  Simple of TagSet.t
	     | Complex of TagSet.t * Tree.Predicate.t
  and predicate = Or of predicate*predicate
    		  | And of predicate*predicate
		    | Not of predicate
		    | Expr of expression
  and expression =  Path of path
		    | Function of string*expression list
		    | Int of int
		    | String of string
		    | True | False
  type t = path
  val print : Format.formatter -> path -> unit
  val print_step : Format.formatter -> step -> unit
  val print_axis : Format.formatter -> axis -> unit
  val print_test : Format.formatter -> test -> unit
  val print_predicate : Format.formatter -> predicate -> unit
  val print_expression : Format.formatter -> expression -> unit
end


val parse : string -> Ast.path