+(* Copyright (C) 2002, 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/.
+ *)
+
+open CicReduction
+open PrimitiveTactics
+open ProofEngineTypes
+open UriManager
+
+(** DEBUGGING *)
+
+ (** perform debugging output? *)
+let debug = false
+
+ (** debugging print *)
+let warn s =
+ if debug then
+ prerr_endline ("TACTICALS WARNING: " ^ s)
+
+(** AUX TACTIC{,AL}S *)
+
+ (**
+ naive implementation of ORELSE tactical, try a sequence of tactics in turn:
+ if one fails pass to the next one and so on, eventually raises (failure "no
+ tactics left")
+ TODO warning: not tail recursive due to "try .. with" boxing
+ *)
+let rec try_tactics ~(tactics: (string * tactic) list) ~status =
+ warn "in Ring.try_tactics";
+ match tactics with
+ | (descr, tac)::tactics ->
+ warn ("Ring.try_tactics IS TRYING " ^ descr);
+ (try
+ let res = tac ~status in
+ warn ("Ring.try_tactics: " ^ descr ^ " succedeed!!!");
+ res
+ with
+ e ->
+ match e with
+ (Fail _)
+ | (CicTypeChecker.NotWellTyped _)
+ | (CicUnification.UnificationFailed) ->
+ warn (
+ "Ring.try_tactics failed with exn: " ^
+ Printexc.to_string e);
+ try_tactics ~tactics ~status
+ | _ -> raise e (* [e] must not be caught ; let's re-raise it *)
+ )
+ | [] -> raise (Fail "try_tactics: no tactics left")
+
+let thens ~start ~continuations ~status =
+ let (proof,new_goals) = start ~status in
+ try
+ List.fold_left2
+ (fun (proof,goals) goal tactic ->
+ let (proof',new_goals') = tactic ~status:(proof,goal) in
+ (proof',goals@new_goals')
+ ) (proof,[]) new_goals continuations
+ with
+ Invalid_argument _ -> raise (Fail "thens: wrong number of new goals")
+
+let then_ ~start ~continuation ~status =
+ let (proof,new_goals) = start ~status in
+ List.fold_left
+ (fun (proof,goals) goal ->
+ let (proof',new_goals') = continuation ~status:(proof,goal) in
+ (proof',goals@new_goals')
+ ) (proof,[]) new_goals