(* Copyright (C) 2000, HELM Team.
 * 
 * This file is part of HELM, an Hypertextual, Electronic
 * Library of Mathematics, developed at the Computer Science
 * Department, University of Bologna, Italy.
 * 
 * HELM is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * HELM is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HELM; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA  02111-1307, USA.
 * 
 * For details, see the HELM World-Wide-Web page,
 * http://cs.unibo.it/helm/.
 *)

(******************************************************************************)
(*                                                                            *)
(*                               PROJECT HELM                                 *)
(*                                                                            *)
(*                     Ferruccio Guidi <fguidi@cs.unibo.it>                   *)
(*                     Domenico Lordi  <lordi@cs.unibo.it>                    *)
(*                                 30/04/2002                                 *)
(*                                                                            *)
(*                                                                            *)
(******************************************************************************)

exception MQInvalidURI of string
exception MQConnectionFailed of string
exception MQInvalidConnection of string

(* Input types **************************************************************)
(* main type is mquery                                                      *)

type mqrvar = string                       (* name *)

type mqsvar = string                       (* name *)

type mquptoken =
   | MQString of string                     (* a constant string *)
   | MQSlash                                (* a slash: '/' *)
   | MQAnyChr                               (* Any single character: '?' *)
   | MQAst                                  (* single asterisk: '*' *)
   | MQAstAst                               (* double asterisk: '**' *)

type mqup = mquptoken list                  (* uri pattern (helper) *)

type mqfi = int option * int option

type mqtref = string * mqup * string * mqfi (* HELM preamble,
                                              uri pattern, 
                                              extension, 
					      fragment identifier *)

type mqpattern = mqtref                     (* constant pattern *)

type mqfunc =
   | MQName                                 (* NAME *)

type mqstring =
   | MQCons of string                       (* constant *)
   | MQFunc of mqfunc * mqrvar              (* function, rvar *)
   | MQRVar of mqrvar                       (* rvar *)
   | MQSVar of mqsvar                       (* svar *)
   | MQMConclusion                          (* main conclusion *)
   | MQConclusion                           (* inner conclusion *)

type mqbool =
   | MQTrue
   | MQFalse
   | MQAnd of mqbool * mqbool
   | MQOr of mqbool * mqbool
   | MQNot of mqbool
   | MQIs of mqstring * mqstring            (* operands *)

type mqlist =
   | MQSelect of mqrvar * mqlist * mqbool   (* rvar, list, boolean *) 
   | MQUse of mqlist * mqsvar               (* list, Position attribute *)
   | MQUsedBy of mqlist * mqsvar            (* list, Position attribute *)
   | MQPattern of mqpattern                 (* pattern *)
   | MQUnion of mqlist * mqlist             (*  *)
   | MQIntersect of mqlist * mqlist         (*  *)

type mquery =
   | MQList of mqlist
   
(* Output types *************************************************************)
(* main type is mqresult                                                    *)

(* TODO: usare le uri in questo formato *)
type mquref = UriManager.uri * mqfi         (* uri, fragment identifier *)

type mqrefs = mqtref list                   (* list of references (helper) *)

type mqresult =                         
   | MQStrUri of string list
   | MQRefs of mqrefs