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(***********************************************************************)
(* v * The Coq Proof Assistant / The Coq Development Team *)
(* <O___,, * INRIA-Rocquencourt & LRI-CNRS-Orsay *)
(* \VV/ *************************************************************)
(* // * The HELM Project / The EU MoWGLI Project *)
(* * University of Bologna *)
(***********************************************************************)
(* Copyright (C) 2000-2004, 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.unibo.it/.
*)
exception CanNotUnshare;;
(* [unshare t] gives back a copy of t where all sharing has been removed *)
(* Physical equality becomes meaningful on unshared terms. Hashtables that *)
(* use physical equality can now be used to associate information to evey *)
(* node of the term. *)
let unshare ?(already_unshared = function _ -> false) t =
let obj = Obj.repr t in
let rec aux obj =
if already_unshared (Obj.obj obj) then
obj
else
(if Obj.is_int obj then
obj
else if Obj.is_block obj then
begin
let tag = Obj.tag obj in
if tag < Obj.no_scan_tag then
begin
let size = Obj.size obj in
let new_obj = Obj.new_block 0 size in
Obj.set_tag new_obj tag ;
for i = 0 to size - 1 do
Obj.set_field new_obj i (aux (Obj.field obj i))
done ;
new_obj
end
else if tag = Obj.string_tag then
obj
else
raise CanNotUnshare
end
else
raise CanNotUnshare
)
in
Obj.obj (aux obj)
;;
|
