(* Copyright (C) 2004, 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://helm.cs.unibo.it/
 *)

open CicTextualParser2Ast
open CicTextualParser2

EXTEND
  term: LEVEL "add"
    [
      [ t1 = term; SYMBOL <:unicode<lor>> (* ∨ *); t2 = term ->
          return_term loc (Appl_symbol ("or", 0, [t1; t2]))
      ]
    ];
  term: LEVEL "mult"
    [
      [ t1 = term; SYMBOL <:unicode<land>> (* ∧ *); t2 = term ->
        return_term loc (Appl_symbol ("and", 0, [t1; t2]))
      ]
    ];
  term: LEVEL "inv"
    [
      [ SYMBOL <:unicode<lnot>> (* ¬ *); t = term ->
        return_term loc (Appl_symbol ("not", 0, [t])) ]
    ];
END

let _ =
  DisambiguateChoices.add_symbol_choice "eq"
    ("leibnitz's equality",
     (fun interp _ args ->
       let t1, t2 =
         match args with
         | [t1; t2] -> t1, t2
         | _ -> raise DisambiguateChoices.Invalid_choice
       in
       Cic.Appl [
         Cic.MutInd (HelmLibraryObjects.Logic.eq_URI, 0, []);
           Cic.Implicit; t1; t2
       ]))