(***********************************************************************)
(*                                                                     *)
(*                               TAToo                                 *)
(*                                                                     *)
(*                  Lucca Hirschi, ?   *)
(*                  ?   *)
(*                                                                     *)
(*  Copyright 2010-2012 Université Paris-Sud and Centre National de la *)
(*  Recherche Scientifique. All rights reserved.  This file is         *)
(*  distributed under the terms of the GNU Lesser General Public       *)
(*  License, with the special exception on linking described in file   *)
(*  ../LICENSE.                                                        *)
(*                                                                     *)
(***********************************************************************)

open XPath.Ast
open Formula.Infix

exception Not_core_XPath of path
(** Raised whenever the XPath query contains not implemented structures *)

let trans query =
  let asta = Asta.empty in
  let rec trans = function
    | [s] -> trans_last s
    | s :: tl -> trans_step s; trans tl
    | [] -> ()
      
  and trans_init () = 			(* add THE top state  *)
    let top_st = Asta.new_state () in
    let or_top = 
      List.fold_left (fun acc x -> (`Left *+ x +| acc))
	Formula.true_ (Asta.top_states asta)
    in
    Asta.add_tr asta (top_st, Asta.any_label, or_top)
      
  and trans_last (ax,test,pred) =	(* a selecting state is needed *)
    ()
      
  and trans_step (ax,test,pred) =
    ()
      
  and trans_pr p = ()

  in
  match query with
    | Absolute steps -> trans_init(); trans steps; asta
    | AbsoluteDoS steps as x -> raise (Not_core_XPath x)
    | Relative steps as x -> raise (Not_core_XPath x)