branch for universe

[helm.git] / components / tactics / paramodulation / equality_indexing.ml

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+(* 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://cs.unibo.it/helm/.
+ *)
+
+(* $Id$ *)
+
+module type EqualityIndex =
+  sig
+    module PosEqSet : Set.S with type elt = Utils.pos * Equality.equality
+    type t = Discrimination_tree.DiscriminationTreeIndexing(PosEqSet).t
+    val empty : t
+    val retrieve_generalizations : t -> Cic.term -> PosEqSet.t
+    val retrieve_unifiables : t -> Cic.term -> PosEqSet.t
+    val init_index : unit -> unit
+    val remove_index : t -> Equality.equality -> t
+    val index : t -> Equality.equality -> t
+    val in_index : t -> Equality.equality -> bool
+  end
+
+module DT = 
+struct
+    module OrderedPosEquality = struct
+       type t = Utils.pos * Equality.equality
+       let compare (p1,e1) (p2,e2) = 
+         let rc = Pervasives.compare p1 p2 in
+           if rc = 0 then Equality.compare e1 e2 else rc
+      end
+
+    module PosEqSet = Set.Make(OrderedPosEquality);;
+    
+    include Discrimination_tree.DiscriminationTreeIndexing(PosEqSet)
+    
+
+    (* DISCRIMINATION TREES *)
+    let init_index () = () ;;
+
+    let remove_index tree equality = 
+      let _, _, (_, l, r, ordering), _,_ = Equality.open_equality equality in
+       match ordering with
+         | Utils.Gt -> remove_index tree l (Utils.Left, equality)
+         | Utils.Lt -> remove_index tree r (Utils.Right, equality)
+         | _ -> 
+             let tree = remove_index tree r (Utils.Right, equality) in
+               remove_index tree l (Utils.Left, equality)
+
+    let index tree equality = 
+      let _, _, (_, l, r, ordering), _,_ = Equality.open_equality equality in
+       match ordering with
+         | Utils.Gt -> index tree l (Utils.Left, equality)
+         | Utils.Lt -> index tree r (Utils.Right, equality)
+         | _ -> 
+             let tree = index tree r (Utils.Right, equality) in
+               index tree l (Utils.Left, equality)
+  
+
+    let in_index tree equality = 
+      let _, _, (_, l, r, ordering), _,_ = Equality.open_equality equality in
+      let meta_convertibility (pos,equality') = 
+       Equality.meta_convertibility_eq equality equality' 
+      in
+       in_index tree l meta_convertibility || in_index tree r meta_convertibility
+
+  end
+
+module PT = 
+  struct
+    module OrderedPosEquality = struct
+       type t = Utils.pos * Equality.equality
+       let compare (p1,e1) (p2,e2) = 
+         let rc = Pervasives.compare p1 p2 in
+           if rc = 0 then Equality.compare e1 e2 else rc
+      end
+
+    module PosEqSet = Set.Make(OrderedPosEquality);;
+    
+    include Discrimination_tree.DiscriminationTreeIndexing(PosEqSet)
+    
+
+    (* DISCRIMINATION TREES *)
+    let init_index () = () ;;
+
+    let remove_index tree equality = 
+      let _, _, (_, l, r, ordering), _,_ = Equality.open_equality equality in
+         match ordering with
+         | Utils.Gt -> remove_index tree l (Utils.Left, equality)
+         | Utils.Lt -> remove_index tree r (Utils.Right, equality)
+         | _ -> 
+             let tree = remove_index tree r (Utils.Right, equality) in
+               remove_index tree l (Utils.Left, equality)
+
+    let index tree equality = 
+      let _, _, (_, l, r, ordering), _,_ = Equality.open_equality equality in
+       match ordering with
+         | Utils.Gt -> index tree l (Utils.Left, equality)
+         | Utils.Lt -> index tree r (Utils.Right, equality)
+         | _ -> 
+             let tree = index tree r (Utils.Right, equality) in
+               index tree l (Utils.Left, equality)
+  
+
+    let in_index tree equality = 
+      let _, _, (_, l, r, ordering), _,_ = Equality.open_equality equality in
+      let meta_convertibility (pos,equality') = 
+       Equality.meta_convertibility_eq equality equality' 
+      in
+       in_index tree l meta_convertibility || in_index tree r meta_convertibility
+end
+