(* 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/.
 *)

type id = string (* identifier *)

type qid = id * bool * id list (* qualified identifier: name, is local?, qualifiers *)

type term = Sort of bool              (* sorts: true = TYPE, false = PROP *)
	  | GRef of qid * term list   (* reference: name, arguments *)
	  | Appl of term * term       (* application: argument, function *)
	  | Abst of id * term * term  (* abstraction: name, type, body *)
	  
type item = Section of id option           (* section: Some = open/reopen, None = close last *)
	  | Context of qid option          (* context: Some = last node, None = root *)
	  | Block of id * term             (* block opener: name, type *)
	  | Decl of id * term              (* declaration: name, type *)
	  | Def of id * term * bool * term (* definition: name, type, transparent?, body *)
	  
type book = item list (* book *)