]> matita.cs.unibo.it Git - helm.git/blobdiff - helm/ocaml/tactics/discriminationTactics.ml
This commit was manufactured by cvs2svn to create branch 'moogle'.
[helm.git] / helm / ocaml / tactics / discriminationTactics.ml
diff --git a/helm/ocaml/tactics/discriminationTactics.ml b/helm/ocaml/tactics/discriminationTactics.ml
deleted file mode 100644 (file)
index dd2e68d..0000000
+++ /dev/null
@@ -1,562 +0,0 @@
-(* 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 HelmLibraryObjects
-
-let rec injection_tac ~term status = 
-  let (proof, goal) = status in
-  let module C = Cic in
-  let module U = UriManager in
-  let module P = PrimitiveTactics in
-  let module T = Tacticals in
-   let _,metasenv,_,_ = proof in
-    let _,context,_ = CicUtil.lookup_meta goal metasenv in
-     let termty = (CicTypeChecker.type_of_aux' metasenv context term) in  
-      (match termty with
-          (C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2])
-             when (U.eq equri Logic.eq_URI) -> (
-           match tty with
-              (C.MutInd (turi,typeno,exp_named_subst))
-            | (C.Appl (C.MutInd (turi,typeno,exp_named_subst)::_)) -> (
-                   match t1,t2 with
-                      ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1)),
-                       (C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2)))
-                         when (uri1 = uri2) && (typeno1 = typeno2) && (consno1 = consno2) && (exp_named_subst1 = exp_named_subst2) ->
-                       (* raise (ProofEngineTypes.Fail "Injection: nothing to do") ; *) T.id_tac
-                    | ((C.Appl ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1))::applist1)),
-                       (C.Appl ((C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2))::applist2)))
-                         when (uri1 = uri2) && (typeno1 = typeno2) && (consno1 = consno2) && (exp_named_subst1 = exp_named_subst2) ->
-                       let rec traverse_list i l1 l2 =
-                         match l1,l2 with
-                            [],[] -> T.id_tac
-                          | hd1::tl1,hd2::tl2 -> 
-                             T.then_ 
-                              ~start:(injection1_tac ~i ~term)
-                              ~continuation:(traverse_list (i+1) tl1 tl2)
-                          | _ -> raise (ProofEngineTypes.Fail "Discriminate: i 2 termini hanno in testa lo stesso costruttore, ma applicato a un numero diverso di termini. possibile???") ; T.id_tac
-                       in traverse_list 1 applist1 applist2
-                    | ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1)),
-                       (C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2)))
-                    | ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1)),
-                       (C.Appl ((C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2))::_)))
-                    | ((C.Appl ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1))::_)),
-                       (C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2)))
-                    | ((C.Appl ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1))::_)),
-                       (C.Appl ((C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2))::_)))
-                         when (consno1 <> consno2) || (exp_named_subst1 <> exp_named_subst2) ->
-                       (* raise (ProofEngineTypes.Fail "Injection: not a projectable equality but a discriminable one") ; *) T.id_tac
-                    | _ -> (* raise (ProofEngineTypes.Fail "Injection: not a projectable equality") ; *) T.id_tac
-                   )
-            | _ -> raise (ProofEngineTypes.Fail "Injection: not a projectable equality")
-           )
-        | _ -> raise (ProofEngineTypes.Fail "Injection: not an equation")
-      ) status
-
-
-and injection1_tac ~term ~i status = 
-let (proof, goal) = status in
-(* precondizione: t1 e t2 hanno in testa lo stesso costruttore ma differiscono (o potrebbero differire?) nell'i-esimo parametro del costruttore *)
-  let module C = Cic in
-  let module S = CicSubstitution in
-  let module U = UriManager in
-  let module P = PrimitiveTactics in
-  let module T = Tacticals in
-   let _,metasenv,_,_ = proof in
-    let _,context,_ = CicUtil.lookup_meta goal metasenv in
-     let termty = (CicTypeChecker.type_of_aux' metasenv context term) in
-      match termty with (* an equality *)
-         (C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2])
-            when (U.eq equri Logic.eq_URI) -> (
-          match tty with (* some inductive type *)
-             (C.MutInd (turi,typeno,exp_named_subst))
-           | (C.Appl (C.MutInd (turi,typeno,exp_named_subst)::_)) ->
-prerr_endline ("XXXX term " ^ CicPp.ppterm term) ;
-prerr_endline ("XXXX termty " ^ CicPp.ppterm termty) ;
-prerr_endline ("XXXX t1 " ^ CicPp.ppterm t1) ;
-prerr_endline ("XXXX t2 " ^ CicPp.ppterm t2) ;
-prerr_endline ("XXXX tty " ^ CicPp.ppterm tty) ;
-              let t1',t2',consno = (* sono i due sottotermini che differiscono *)
-               match t1,t2 with
-                  ((C.Appl ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1))::applist1)),
-                   (C.Appl ((C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2))::applist2)))
-                     when (uri1 = uri2) && (typeno1 = typeno2) && (consno1 = consno2) && (exp_named_subst1 = exp_named_subst2) -> (* controllo ridondante *)
-                   (List.nth applist1 (i-1)),(List.nth applist2 (i-1)),consno2
-                | _ -> raise (ProofEngineTypes.Fail "Injection: qui non dovrei capitarci mai")
-              in
-               let tty' = (CicTypeChecker.type_of_aux' metasenv context t1') in
-prerr_endline ("XXXX tty' " ^ CicPp.ppterm tty') ;
-prerr_endline ("XXXX t1' " ^ CicPp.ppterm t1') ;
-prerr_endline ("XXXX t2' " ^ CicPp.ppterm t2') ;
-prerr_endline ("XXXX consno " ^ string_of_int consno) ;
-               let pattern =
-                     match (CicEnvironment.get_obj turi) with
-                        C.InductiveDefinition (ind_type_list,_,nr_ind_params_dx)  ->
-                         let _,_,_,constructor_list = (List.nth ind_type_list typeno) in
-                          let i_constr_id,_ = List.nth constructor_list (consno - 1) in
-                           List.map
-                            (function (id,cty) ->
-                              let reduced_cty = CicReduction.whd context cty in
-                               let rec aux t k =
-                                match t with
-                                   C.Prod (_,_,target) when (k <= nr_ind_params_dx) ->
-                                    aux target (k+1)
-                                 | C.Prod (binder,source,target) when (k > nr_ind_params_dx) ->
-                                   let binder' =
-                                     match binder with
-                                        C.Name b -> C.Name b
-                                      | C.Anonymous -> C.Name "y"
-                                    in
-                                     C.Lambda (binder',source,(aux target (k+1)))
-                                 | _ ->
-                                    let nr_param_constr = k - 1 - nr_ind_params_dx in
-                                     if (id = i_constr_id)
-                                      then C.Rel (nr_param_constr - i + 1)
-                                      else S.lift (nr_param_constr + 1) t1' (* + 1 per liftare anche il lambda agguinto esternamente al case *)
-                               in aux reduced_cty 1
-                            )
-                            constructor_list
-                      | _ -> raise (ProofEngineTypes.Fail "Discriminate: object is not an Inductive Definition: it's imposible")
-               in
-prerr_endline ("XXXX cominciamo!") ;
-                T.thens 
-                 ~start:(P.cut_tac (C.Appl [(C.MutInd (equri,0,[])) ; tty' ; t1' ; t2']))
-                 ~continuations:[
-                   T.then_ 
-                    ~start:(injection_tac ~term:(C.Rel 1))
-                    ~continuation:T.id_tac (* !!! qui devo anche fare clear di term tranne al primo passaggio *) 
-                   ;
-                   T.then_ 
-                    ~start:
-                      (fun status ->    
-                        let (proof, goal) = status in
-                        let _,metasenv,_,_ = proof in
-                         let _,context,gty = CicUtil.lookup_meta goal metasenv in
-prerr_endline ("XXXX goal " ^ string_of_int goal) ;
-prerr_endline ("XXXX gty " ^ CicPp.ppterm gty) ;
-prerr_endline ("XXXX old t1' " ^ CicPp.ppterm t1') ;
-prerr_endline ("XXXX change " ^ CicPp.ppterm (C.Appl [ C.Lambda (C.Name "x", tty, C.MutCase (turi, typeno, (C.Lambda ((C.Name "x"),(S.lift 1 tty),(S.lift 2 tty'))), (C.Rel 1), pattern)); t1])) ;
-                          let new_t1' = 
-                           match gty with 
-                              (C.Appl (C.MutInd (_,_,_)::arglist)) -> 
-                               List.nth arglist 1
-                            | _ -> raise (ProofEngineTypes.Fail "Injection: goal after cut is not correct")
-                          in
-prerr_endline ("XXXX new t1' " ^ CicPp.ppterm new_t1') ;
-                           P.change_tac
-                              ~what:new_t1'
-                              ~with_what:
-                                (C.Appl [
-                                  C.Lambda (
-                                   C.Name "x", tty,
-                                   C.MutCase (
-                                    turi, typeno,
-                                    (C.Lambda (
-                                     (C.Name "x"),
-                                     (S.lift 1 tty),
-                                     (S.lift 2 tty'))),
-                                    (C.Rel 1), pattern
-                                   )
-                                  );
-                                  t1]
-                                )
-                       status
-                      )
-                    ~continuation:
-                      (T.then_
-                        ~start:(EqualityTactics.rewrite_simpl_tac ~term)
-                        ~continuation:EqualityTactics.reflexivity_tac
-                      )
-                  ]     
-                 status
-           | _ -> raise (ProofEngineTypes.Fail "Discriminate: not a discriminable equality")
-          )
-       | _ -> raise (ProofEngineTypes.Fail "Discriminate: not an equality")
-;;
-
-
-
-exception TwoDifferentSubtermsFound of int 
-
-(* term ha tipo t1=t2; funziona solo se t1 e t2 hanno in testa costruttori
-diversi *)
-
-let discriminate'_tac ~term status = 
-  let (proof, goal) = status in
-  let module C = Cic in
-  let module U = UriManager in
-  let module P = PrimitiveTactics in
-  let module T = Tacticals in
-   let _,metasenv,_,_ = proof in
-    let _,context,_ = CicUtil.lookup_meta goal metasenv in
-     let termty = (CicTypeChecker.type_of_aux' metasenv context term) in
-      match termty with
-         (C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2]) 
-          when (U.eq equri Logic.eq_URI) -> (
-           match tty with
-              (C.MutInd (turi,typeno,exp_named_subst))
-            | (C.Appl (C.MutInd (turi,typeno,exp_named_subst)::_)) ->
-
-                let consno2 = (* bruuutto: uso un eccezione per terminare con successo! buuu!! :-/ *)
-                 try
-                  let rec traverse t1 t2 =
-prerr_endline ("XXXX t1 " ^ CicPp.ppterm t1) ;
-prerr_endline ("XXXX t2 " ^ CicPp.ppterm t2) ;
-                   match t1,t2 with
-                      ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1)),
-                       (C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2)))
-                         when (uri1 = uri2) && (typeno1 = typeno2) && (consno1 = consno2) && (exp_named_subst1 = exp_named_subst2) ->
-                       0
-                    | ((C.Appl ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1))::applist1)),
-                       (C.Appl ((C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2))::applist2))) 
-                         when (uri1 = uri2) && (typeno1 = typeno2) && (consno1 = consno2) && (exp_named_subst1 = exp_named_subst2) ->
-                       let rec traverse_list l1 l2 =
-                         match l1,l2 with
-                            [],[] -> 0
-                          | hd1::tl1,hd2::tl2 -> traverse hd1 hd2; traverse_list tl1 tl2
-                          | _ -> raise (ProofEngineTypes.Fail "Discriminate: i 2 termini hanno in testa lo stesso costruttore, ma applicato a un numero diverso di termini. possibile???")
-                       in traverse_list applist1 applist2
-
-                    | ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1)),
-                       (C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2)))
-                    | ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1)),
-                       (C.Appl ((C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2))::_)))
-                    | ((C.Appl ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1))::_)),
-                       (C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2)))
-                    | ((C.Appl ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1))::_)),
-                       (C.Appl ((C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2))::_)))
-                         when (consno1 <> consno2) || (exp_named_subst1 <> exp_named_subst2) ->
-                       raise (TwoDifferentSubtermsFound consno2)
-                    | _ -> raise (ProofEngineTypes.Fail "Discriminate: not a discriminable equality")
-                  in traverse t1 t2
-                 with (TwoDifferentSubtermsFound consno2) -> consno2
-                in
-prerr_endline ("XXXX consno2 " ^ (string_of_int consno2)) ;
-                 if consno2 = 0 
-                  then raise (ProofEngineTypes.Fail "Discriminate: Discriminating terms are structurally equal")
-                  else
-
-                   let pattern = 
-                     (* a list of "True" except for the element in position consno2 which is "False" *)
-                     match (CicEnvironment.get_obj turi) with
-                        C.InductiveDefinition (ind_type_list,_,nr_ind_params)  ->
-prerr_endline ("XXXX nth " ^ (string_of_int (List.length ind_type_list)) ^ " " ^ (string_of_int typeno)) ;
-                         let _,_,_,constructor_list = (List.nth ind_type_list typeno) in 
-prerr_endline ("XXXX nth " ^ (string_of_int (List.length constructor_list)) ^ " " ^ (string_of_int consno2)) ;
-                          let false_constr_id,_ = List.nth constructor_list (consno2 - 1) in
-prerr_endline ("XXXX nth funzionano ") ;
-                           List.map 
-                            (function (id,cty) ->
-                              let red_ty = CicReduction.whd context cty in (* dubbio: e' corretto ridurre in questo context ??? *)
-                               let rec aux t k =
-                                match t with
-                                   C.Prod (_,_,target) when (k <= nr_ind_params) ->
-                                    aux target (k+1)
-                                 | C.Prod (binder,source,target) when (k > nr_ind_params) -> 
-                                    C.Lambda (binder,source,(aux target (k+1)))
-                                 | _ -> 
-                                    if (id = false_constr_id)
-                                     then (C.MutInd(Logic.false_URI,0,[]))
-                                     else (C.MutInd(Logic.true_URI,0,[]))
-                               in aux red_ty 1
-                            ) 
-                            constructor_list
-                      | _ -> raise (ProofEngineTypes.Fail "Discriminate: object is not an Inductive Definition: it's imposible")
-                   in
-
-                    let (proof',goals') = 
-                     EliminationTactics.elim_type_tac 
-                      ~term:(C.MutInd(Logic.false_URI,0,[]))
-                      status 
-                    in
-                     (match goals' with
-                         [goal'] -> 
-                          let _,metasenv',_,_ = proof' in
-                           let _,context',gty' =
-                             CicUtil.lookup_meta goal' metasenv'
-                           in
-                            T.then_
-                             ~start:
-                              (P.change_tac 
-                               ~what:gty' 
-                               ~with_what:
-                                (C.Appl [
-                                  C.Lambda (
-                                   C.Name "x", tty, 
-                                   C.MutCase (
-                                    turi, typeno,
-                                    (C.Lambda ((C.Name "x"),tty,(C.Sort C.Prop))),
-                                    (C.Rel 1), pattern
-                                   )
-                                  ); 
-                                  t2]
-                                )
-                              )
-                             ~continuation:
-                              (
-prerr_endline ("XXXX rewrite<-: " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' (C.Appl [(C.MutInd (equri,0,[])) ; tty ; t1 ; t2])));
-prerr_endline ("XXXX rewrite<-: " ^ CicPp.ppterm (C.Appl [(C.MutInd (equri,0,[])) ; tty ; t1 ; t2])) ;
-prerr_endline ("XXXX equri: " ^ U.string_of_uri equri) ;
-prerr_endline ("XXXX tty : " ^ CicPp.ppterm tty) ;
-prerr_endline ("XXXX tt1': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t1)) ;
-prerr_endline ("XXXX tt2': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t2)) ;
-if (CicTypeChecker.type_of_aux' metasenv' context' t1) <> tty then prerr_endline ("XXXX tt1': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t1)) ;
-if (CicTypeChecker.type_of_aux' metasenv' context' t2) <> tty then prerr_endline ("XXXX tt2': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t2)) ;
-if (CicTypeChecker.type_of_aux' metasenv' context' t1) <> (CicTypeChecker.type_of_aux' metasenv' context' t2) 
- then prerr_endline ("XXXX tt1': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t1)) ; prerr_endline ("XXXX tt2': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t2)) ;
-prerr_endline ("XXXX rewrite<- " ^ CicPp.ppterm term ^ " : " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' term));
-                                 T.then_
-                                   ~start:(EqualityTactics.rewrite_back_simpl_tac ~term)
-                                   ~continuation:(IntroductionTactics.constructor_tac ~n:1) 
-                              )
-                             (proof',goal')
-                       | _ -> raise (ProofEngineTypes.Fail "Discriminate: ElimType False left more (or less) than one goal")
-                     )    
-            | _ -> raise (ProofEngineTypes.Fail "Discriminate: not a discriminable equality")
-           )
-       | _ -> raise (ProofEngineTypes.Fail "Discriminate: not an equality")
-;;
-
-
-let discriminate_tac ~term status =
-  Tacticals.then_
-   ~start:(* (injection_tac ~term) *) Tacticals.id_tac
-   ~continuation:(discriminate'_tac ~term) (* NOOO!!! non term ma una (qualunque) delle nuove hyp introdotte da inject *)
-   status
-;;
-
-
-
-let decide_equality_tac =
-(* il goal e' un termine della forma t1=t2\/~t1=t2; la tattica decide se l'uguaglianza
-e' vera o no e lo risolve *)
-  Tacticals.id_tac
-;;
-
-
-
-let compare_tac ~term status = Tacticals.id_tac status
-(*
-(* term is in the form t1=t2; the tactic leaves two goals: in the first you have to          *)
-(* demonstrate the goal with the additional hyp that t1=t2, in the second the hyp is ~t1=t2  *)
-  let module C = Cic in
-  let module U = UriManager in
-  let module P = PrimitiveTactics in
-  let module T = Tacticals in
-   let _,metasenv,_,_ = proof in
-    let _,context,gty = CicUtil.lookup_meta goal metasenv in
-     let termty = (CicTypeChecker.type_of_aux' metasenv context term) in
-      match termty with
-         (C.Appl [(C.MutInd (uri, 0, [])); _; t1; t2]) when (uri = (U.uri_of_string "cic:/Coq/Init/Logic/eq.ind")) ->
-          
-          let term' = (* (t1=t2)\/~(t1=t2) *)
-           C.Appl [
-            (C.MutInd ((U.uri_of_string "cic:/Coq/Init/Logic/or.ind"), 0, [])) ; 
-            term ; 
-            C.Appl [
-             (C.MutInd ((U.uri_of_string "cic:/Coq/Init/Logic/eq.ind"), 1, [])) ; 
-             t1 ; 
-             C.Appl [C.Const ((U.uri_of_string "cic:/Coq/Init/Logic/not.con"), []) ; t2]
-            ]
-           ] 
-          in
-            T.thens 
-               ~start:(P.cut_tac ~term:term')
-               ~continuations:[
-                 T.then_ ~start:(P.intros_tac) ~continuation:(P.elim_intros_simpl_tac ~term:(C.Rel 1)) ; 
-                 decide_equality_tac]  
-               status
-      | (C.Appl [(C.MutInd (uri, 0, [])); _; t1; t2]) when (uri = (U.uri_of_string "cic:/Coq/Init/Logic_Type/eqT.ind")) ->
-          let term' = (* (t1=t2) \/ ~(t1=t2) *)
-           C.Appl [
-            (C.MutInd ((U.uri_of_string "cic:/Coq/Init/Logic/or.ind"), 0, [])) ; 
-            term ; 
-            C.Appl [
-             (C.MutInd ((U.uri_of_string "cic:/Coq/Init/Logic_Type/eqT.ind"), 1, [])) ; 
-             t1 ; 
-             C.Appl [C.Const ((U.uri_of_string "cic:/Coq/Init/Logic/not.con"), []) ; t2]
-            ]
-           ] 
-          in
-            T.thens 
-               ~start:(P.cut_tac ~term:term')
-               ~continuations:[
-                 T.then_ ~start:(P.intros_tac) ~continuation:(P.elim_intros_simpl_tac ~term:(C.Rel 1)) ; 
-                 decide_equality_tac]  
-               status
-      | _ -> raise (ProofEngineTypes.Fail "Compare: Not an equality") 
-*)
-;;
-
-
-
-(* DISCRIMINTATE SENZA INJECTION 
-
-exception TwoDifferentSubtermsFound of (Cic.term * Cic.term * int) 
-
-let discriminate_tac ~term status =
-  let module C = Cic in
-  let module U = UriManager in
-  let module P = PrimitiveTactics in
-  let module T = Tacticals in
-  let (proof, goal) = status in
-   let _,metasenv,_,_ = proof in
-    let _,context,_ = CicUtil.lookup_meta goal metasenv in
-     let termty = (CicTypeChecker.type_of_aux' metasenv context term) in
-      match termty with
-         (C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2]) 
-          when (U.eq equri (U.uri_of_string "cic:/Coq/Init/Logic/eq.ind")) 
-            or (U.eq equri (U.uri_of_string "cic:/Coq/Init/Logic_Type/eqT.ind")) -> (
-           match tty with
-              (C.MutInd (turi,typeno,exp_named_subst))
-            | (C.Appl (C.MutInd (turi,typeno,exp_named_subst)::_)) ->
-
-                let (t1',t2',consno2') = (* bruuutto: uso un eccezione per terminare con successo! buuu!! :-/ *)
-                 try
-                  let rec traverse t1 t2 =
-prerr_endline ("XXXX t1 " ^ CicPp.ppterm t1) ;
-prerr_endline ("XXXX t2 " ^ CicPp.ppterm t2) ;
-                   match t1,t2 with
-                      ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1)),
-                       (C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2)))
-                         when (uri1 = uri2) && (typeno1 = typeno2) && (consno1 = consno2) && (exp_named_subst1 = exp_named_subst2) ->
-                       t1,t2,0
-                    | ((C.Appl ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1))::applist1)),
-                       (C.Appl ((C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2))::applist2))) 
-                         when (uri1 = uri2) && (typeno1 = typeno2) && (consno1 = consno2) && (exp_named_subst1 = exp_named_subst2) ->
-                       let rec traverse_list l1 l2 =
-                         match l1,l2 with
-                            [],[] -> t1,t2,0
-                          | hd1::tl1,hd2::tl2 -> traverse hd1 hd2; traverse_list tl1 tl2
-                          | _ -> raise (ProofEngineTypes.Fail "Discriminate: i 2 termini hanno in testa lo stesso costruttore, ma applicato a un numero diverso di termini. possibile???")
-                       in traverse_list applist1 applist2
-
-                    | ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1)),
-                       (C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2)))
-                    | ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1)),
-                       (C.Appl ((C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2))::_)))
-                    | ((C.Appl ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1))::_)),
-                       (C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2)))
-                    | ((C.Appl ((C.MutConstruct (uri1,typeno1,consno1,exp_named_subst1))::_)),
-                       (C.Appl ((C.MutConstruct (uri2,typeno2,consno2,exp_named_subst2))::_)))
-                         when (consno1 <> consno2) || (exp_named_subst1 <> exp_named_subst2) ->
-                       raise (TwoDifferentSubtermsFound (t1,t2,consno2))
-                    | _ -> raise (ProofEngineTypes.Fail "Discriminate: not a discriminable equality")
-                  in traverse t1 t2
-                 with (TwoDifferentSubtermsFound (t1,t2,consno2)) -> (t1,t2,consno2)
-                in
-prerr_endline ("XXXX consno2' " ^ (string_of_int consno2')) ;
-                 if consno2' = 0 
-                  then raise (ProofEngineTypes.Fail "Discriminate: Discriminating terms are structurally equal")
-                  else
-
-                   let pattern = 
-                     (* a list of "True" except for the element in position consno2' which is "False" *)
-                     match (CicEnvironment.get_obj turi) with
-                        C.InductiveDefinition (ind_type_list,_,nr_ind_params)  ->
-prerr_endline ("XXXX nth " ^ (string_of_int (List.length ind_type_list)) ^ " " ^ (string_of_int typeno)) ;
-                         let _,_,_,constructor_list = (List.nth ind_type_list typeno) in 
-prerr_endline ("XXXX nth " ^ (string_of_int (List.length constructor_list)) ^ " " ^ (string_of_int consno2')) ;
-                          let false_constr_id,_ = List.nth constructor_list (consno2' - 1) in
-prerr_endline ("XXXX nth funzionano ") ;
-                           List.map 
-                            (function (id,cty) ->
-                              let red_ty = CicReduction.whd context cty in (* dubbio: e' corretto ridurre in questo context ??? *)
-                               let rec aux t k =
-                                match t with
-                                   C.Prod (_,_,target) when (k <= nr_ind_params) ->
-                                    aux target (k+1)
-                                 | C.Prod (binder,source,target) when (k > nr_ind_params) -> 
-                                    C.Lambda (binder,source,(aux target (k+1)))
-                                 | _ -> 
-                                    if (id = false_constr_id)
-                                     then (C.MutInd (U.uri_of_string "cic:/Coq/Init/Logic/False.ind") 0 [])
-                                     else (C.MutInd (U.uri_of_string "cic:/Coq/Init/Logic/True.ind") 0 [])
-                               in aux red_ty 1
-                            ) 
-                            constructor_list
-                      | _ -> raise (ProofEngineTypes.Fail "Discriminate: object is not an Inductive Definition: it's imposible")
-                   in
-
-                    let (proof',goals') = 
-                     EliminationTactics.elim_type_tac 
-                      ~term:(C.MutInd (U.uri_of_string "cic:/Coq/Init/Logic/False.ind") 0 [] ) 
-                      status 
-                    in
-                     (match goals' with
-                         [goal'] -> 
-                          let _,metasenv',_,_ = proof' in
-                           let _,context',gty' =
-                             CicUtil.lookup_meta goal' metasenv'
-                           in
-                            T.then_
-                             ~start:
-                              (P.change_tac 
-                               ~what:gty' 
-                               ~with_what:
-                                (C.Appl [
-                                  C.Lambda (
-                                   C.Name "x", tty, 
-                                   C.MutCase (
-                                    turi, typeno,
-                                    (C.Lambda ((C.Name "x"),tty,(C.Sort C.Prop))),
-                                    (C.Rel 1), pattern
-                                   )
-                                  ); 
-                                  t2']
-                                )
-                              )
-                             ~continuation:
-                              (
-prerr_endline ("XXXX rewrite<-: " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' (C.Appl [(C.MutInd (equri,0,[])) ; tty ; t1' ; t2'])));
-prerr_endline ("XXXX rewrite<-: " ^ CicPp.ppterm (C.Appl [(C.MutInd (equri,0,[])) ; tty ; t1' ; t2'])) ;
-prerr_endline ("XXXX equri: " ^ U.string_of_uri equri) ;
-prerr_endline ("XXXX tty : " ^ CicPp.ppterm tty) ;
-prerr_endline ("XXXX tt1': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t1')) ;
-prerr_endline ("XXXX tt2': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t2')) ;
-if (CicTypeChecker.type_of_aux' metasenv' context' t1') <> tty then prerr_endline ("XXXX tt1': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t1')) ;
-if (CicTypeChecker.type_of_aux' metasenv' context' t2') <> tty then prerr_endline ("XXXX tt2': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t2')) ;
-if (CicTypeChecker.type_of_aux' metasenv' context' t1') <> (CicTypeChecker.type_of_aux' metasenv' context' t2') 
- then prerr_endline ("XXXX tt1': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t1')) ; prerr_endline ("XXXX tt2': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t2')) ;
-
-                               let termty' = ProofEngineReduction.replace_lifting ~equality:(==) ~what:t1 ~with_what:t1' ~where:termty in
-                                let termty'' = ProofEngineReduction.replace_lifting ~equality:(==) ~what:t2 ~with_what:t2' ~where:termty' in
-
-prerr_endline ("XXXX rewrite<- " ^ CicPp.ppterm term ^ " : " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' term));
-                                 T.then_
-                                   ~start:(EqualityTactics.rewrite_back_simpl_tac ~term:term)
-                                   ~continuation:(IntroductionTactics.constructor_tac ~n:1) 
-                              )
-                             (proof',goal')
-                       | _ -> raise (ProofEngineTypes.Fail "Discriminate: ElimType False left more (or less) than one goal")
-                     )    
-            | _ -> raise (ProofEngineTypes.Fail "Discriminate: not a discriminable equality")
-           )
-       | _ -> raise (ProofEngineTypes.Fail "Discriminate: not an equality")
-;;
-
-*)
-
-
-