+(* 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://www.cs.unibo.it/helm/.
+ *)
+
+(*
+ * implementazione dei comandi LETIN e REF
+ *)
+
+open MathQL;;
+
+let letin_pool = ref None;;
+
+let see_pool () =
+ match !letin_pool with
+ None -> print_endline "None"
+ | Some c -> List.iter (fun elem -> print_endline (fst elem)) c
+;;
+
+let letin_ex rvar alist =
+ let _ =
+ match !letin_pool with
+ Some pool -> letin_pool := Some ((rvar,alist)::(List.remove_assoc rvar pool))
+ | None -> letin_pool := Some ([(rvar,alist)])
+ in
+(* let _ = see_pool () in*)
+ []
+;;
+
+let letref_ex rvar =
+ match !letin_pool with
+ None -> []
+ | Some pool ->
+ (
+ try
+ List.assoc rvar pool
+ with
+ Not_found -> let _ = print_endline "nun ce sta" in []
+ )
+;;
+