+(* Copyright (C) 2005, 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/
+ *)
+
+module Make :
+ functor (M : Map.S) ->
+ sig
+ type key = M.key list
+ type 'a t = Node of 'a option * 'a t M.t
+ val empty : 'a t
+ val find : M.key list -> 'a t -> 'a
+ val mem : M.key list -> 'a t -> bool
+ val add : M.key list -> 'a -> 'a t -> 'a t
+ val remove : M.key list -> 'a t -> 'a t
+ val map : ('a -> 'b) -> 'a t -> 'b t
+ val mapi : (M.key list -> 'a -> 'b) -> 'a t -> 'b t
+ val iter : (M.key list -> 'a -> 'b) -> 'a t -> unit
+ val fold : (M.key list -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
+ val compare : ('a -> 'a -> int) -> 'a t -> 'a t -> int
+ val equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> bool
+ val is_empty : 'a t -> bool
+ end