]> matita.cs.unibo.it Git - helm.git/blobdiff - helm/ocaml/tactics/discriminationTactics.ml
version 0.7.1
[helm.git] / helm / ocaml / tactics / discriminationTactics.ml
index 5523c137ce80c3f539b632ef41580a60e9b690f5..590b482c716db80b74b83429aa4808fbb804aa38 100644 (file)
  * http://cs.unibo.it/helm/.
  *)
 
-open HelmLibraryObjects
+let debug_print = fun _ -> ()
 
-let rec injection_tac ~term ~status:((proof, goal) as status) = 
+let rec injection_tac ~term =
+ let 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  
+  let _,metasenv,_,_ = proof in
+  let _,context,_ = CicUtil.lookup_meta goal metasenv in
+  let termty,_ = (* TASSI: FIXME *)
+    CicTypeChecker.type_of_aux' metasenv context term CicUniv.empty_ugraph in  
+    ProofEngineTypes.apply_tactic
       (match termty with
           (C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2])
-             when (U.eq equri Logic.eq_URI) -> (
+             when LibraryObjects.is_eq_URI equri -> (
            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) ->
+                         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)))
@@ -71,125 +76,125 @@ let rec injection_tac ~term ~status:((proof, goal) as status) =
             | _ -> raise (ProofEngineTypes.Fail "Injection: not a projectable equality")
            )
         | _ -> raise (ProofEngineTypes.Fail "Injection: not an equation")
-      ) ~status
-
-
-and injection1_tac ~term ~i ~status:((proof, goal) as status) = 
-(* 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
+      ) status
+ in 
+  ProofEngineTypes.mk_tactic (injection_tac ~term)
+
+and injection1_tac ~term ~i = 
+ let 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 *)
+   let _,context,_ = CicUtil.lookup_meta goal metasenv in
+   let termty,_ = (* TASSI: FIXME *)
+     CicTypeChecker.type_of_aux' metasenv context term CicUniv.empty_ugraph 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")
+             when LibraryObjects.is_eq_URI equri -> (
+           match tty with (* some inductive type *)
+              (C.MutInd (turi,typeno,exp_named_subst))
+            | (C.Appl (C.MutInd (turi,typeno,exp_named_subst)::_)) ->
+               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
+                 | _ -> assert false
                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:((proof,goal) as status) ->    
-                        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")
+                let tty',_ = 
+                 CicTypeChecker.type_of_aux' metasenv context t1' 
+                   CicUniv.empty_ugraph  in
+                let pattern =
+                      match fst(CicEnvironment.get_obj 
+                                 CicUniv.empty_ugraph 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
+                ProofEngineTypes.apply_tactic   
+                 (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:(ProofEngineTypes.mk_tactic 
+                       (fun status ->    
+                         let (proof, goal) = status in
+                         let _,metasenv,_,_ = proof in
+                          let _,context,gty = CicUtil.lookup_meta goal metasenv in
+                           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
+                            ProofEngineTypes.apply_tactic 
+                            (ReductionTactics.change_tac
+                               ~pattern:(ProofEngineTypes.conclusion_pattern (Some new_t1'))
+                               (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
+                             ~direction:`LeftToRight
+                             ~pattern:(ProofEngineTypes.conclusion_pattern None)
+                             term)
+                         ~continuation:EqualityTactics.reflexivity_tac
+                       )
+                   ])     
+                  status
+            | _ -> raise (ProofEngineTypes.Fail "Discriminate: not a discriminable equality")
+           )
+        | _ -> raise (ProofEngineTypes.Fail "Discriminate: not an equality")
+ in
+  ProofEngineTypes.mk_tactic (injection1_tac ~term ~i)
 ;;
 
 
@@ -199,17 +204,20 @@ 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:((proof, goal) as status) = 
+let discriminate'_tac ~term =
+ 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
+  let _,metasenv,_,_ = proof in
+  let _,context,_ = CicUtil.lookup_meta goal metasenv in
+  let termty,_ = 
+    CicTypeChecker.type_of_aux' metasenv context term CicUniv.empty_ugraph in
       match termty with
          (C.Appl [(C.MutInd (equri, 0, [])) ; tty ; t1 ; t2]) 
-          when (U.eq equri Logic.eq_URI) -> (
+          when LibraryObjects.is_eq_URI equri -> (
            match tty with
               (C.MutInd (turi,typeno,exp_named_subst))
             | (C.Appl (C.MutInd (turi,typeno,exp_named_subst)::_)) ->
@@ -217,8 +225,6 @@ let discriminate'_tac ~term ~status:((proof, goal) as status) =
                 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)))
@@ -248,20 +254,17 @@ prerr_endline ("XXXX t2 " ^ CicPp.ppterm t2) ;
                   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)) ;
+                     match fst(CicEnvironment.get_obj 
+                                CicUniv.empty_ugraph turi) with
+                        C.InductiveDefinition (ind_type_list,_,nr_ind_params,_)  ->
                          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 ??? *)
@@ -273,8 +276,8 @@ prerr_endline ("XXXX nth funzionano ") ;
                                     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,[]))
+                                     then (C.MutInd(LibraryObjects.false_URI (),0,[]))
+                                     else (C.MutInd(LibraryObjects.true_URI (),0,[]))
                                in aux red_ty 1
                             ) 
                             constructor_list
@@ -282,9 +285,10 @@ prerr_endline ("XXXX nth funzionano ") ;
                    in
 
                     let (proof',goals') = 
-                     EliminationTactics.elim_type_tac 
-                      ~term:(C.MutInd(Logic.false_URI,0,[]))
-                      ~status 
+                    ProofEngineTypes.apply_tactic 
+                      (EliminationTactics.elim_type_tac 
+                       (C.MutInd(LibraryObjects.false_URI (),0,[])))
+                      status 
                     in
                      (match goals' with
                          [goal'] -> 
@@ -292,54 +296,52 @@ prerr_endline ("XXXX nth funzionano ") ;
                            let _,context',gty' =
                              CicUtil.lookup_meta goal' metasenv'
                            in
-                            T.then_
+                           ProofEngineTypes.apply_tactic
+                            (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]
-                                )
+                              (ReductionTactics.change_tac 
+                               ~pattern:(ProofEngineTypes.conclusion_pattern (Some gty'))
+                               (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)
+                                   ~start:
+                                     (EqualityTactics.rewrite_simpl_tac
+                                       ~direction:`RightToLeft
+                                       ~pattern:(ProofEngineTypes.conclusion_pattern None)
+                                       term)
                                    ~continuation:(IntroductionTactics.constructor_tac ~n:1) 
-                              )
-                             ~status:(proof',goal')
+                              ))
+                             (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")
+ in
+  ProofEngineTypes.mk_tactic (discriminate'_tac ~term)
 ;;
 
-
-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 discriminate_tac ~term = 
+ let discriminate_tac ~term status =
+  ProofEngineTypes.apply_tactic 
+  (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
+ in
+  ProofEngineTypes.mk_tactic (discriminate_tac ~term)
 ;;
 
 
@@ -352,8 +354,8 @@ e' vera o no e lo risolve *)
 
 
 
-let compare_tac ~term ~status:((proof, goal) as status) = Tacticals.id_tac ~status
-(*
+let compare_tac ~term = Tacticals.id_tac
+ (*
 (* 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
@@ -382,7 +384,7 @@ let compare_tac ~term ~status:((proof, goal) as status) = Tacticals.id_tac ~stat
                ~continuations:[
                  T.then_ ~start:(P.intros_tac) ~continuation:(P.elim_intros_simpl_tac ~term:(C.Rel 1)) ; 
                  decide_equality_tac]  
-               ~status
+               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 [
@@ -400,7 +402,7 @@ let compare_tac ~term ~status:((proof, goal) as status) = Tacticals.id_tac ~stat
                ~continuations:[
                  T.then_ ~start:(P.intros_tac) ~continuation:(P.elim_intros_simpl_tac ~term:(C.Rel 1)) ; 
                  decide_equality_tac]  
-               ~status
+               status
       | _ -> raise (ProofEngineTypes.Fail "Compare: Not an equality") 
 *)
 ;;
@@ -411,11 +413,12 @@ let compare_tac ~term ~status:((proof, goal) as status) = Tacticals.id_tac ~stat
 
 exception TwoDifferentSubtermsFound of (Cic.term * Cic.term * int) 
 
-let discriminate_tac ~term ~status:((proof, goal) as status) =
+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
@@ -430,8 +433,8 @@ let discriminate_tac ~term ~status:((proof, goal) as status) =
                 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) ;
+debug_print ("XXXX t1 " ^ CicPp.ppterm t1) ;
+debug_print ("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)))
@@ -461,20 +464,21 @@ prerr_endline ("XXXX t2 " ^ CicPp.ppterm t2) ;
                   in traverse t1 t2
                  with (TwoDifferentSubtermsFound (t1,t2,consno2)) -> (t1,t2,consno2)
                 in
-prerr_endline ("XXXX consno2' " ^ (string_of_int consno2')) ;
+debug_print ("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
+                     match fst(CicEnvironment.get_obj turi 
+                                 CicUniv.empty_ugraph) 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)) ;
+debug_print ("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')) ;
+debug_print ("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 ") ;
+debug_print ("XXXX nth funzionano ") ;
                            List.map 
                             (function (id,cty) ->
                               let red_ty = CicReduction.whd context cty in (* dubbio: e' corretto ridurre in questo context ??? *)
@@ -497,7 +501,7 @@ prerr_endline ("XXXX nth funzionano ") ;
                     let (proof',goals') = 
                      EliminationTactics.elim_type_tac 
                       ~term:(C.MutInd (U.uri_of_string "cic:/Coq/Init/Logic/False.ind") 0 [] ) 
-                      ~status 
+                      status 
                     in
                      (match goals' with
                          [goal'] -> 
@@ -524,26 +528,27 @@ prerr_endline ("XXXX nth funzionano ") ;
                               )
                              ~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')) ;
+debug_print ("XXXX rewrite<-: " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' (C.Appl [(C.MutInd (equri,0,[])) ; tty ; t1' ; t2'])));
+debug_print ("XXXX rewrite<-: " ^ CicPp.ppterm (C.Appl [(C.MutInd (equri,0,[])) ; tty ; t1' ; t2'])) ;
+debug_print ("XXXX equri: " ^ U.string_of_uri equri) ;
+debug_print ("XXXX tty : " ^ CicPp.ppterm tty) ;
+debug_print ("XXXX tt1': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t1')) ;
+debug_print ("XXXX tt2': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t2')) ;
+if (CicTypeChecker.type_of_aux' metasenv' context' t1') <> tty then debug_print ("XXXX tt1': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux' metasenv' context' t1')) ;
+if (CicTypeChecker.type_of_aux' metasenv' context' t2') <> tty then debug_print ("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')) ;
+ then debug_print ("XXXX tt1': " ^ CicPp.ppterm (CicTypeChecker.type_of_aux'
+ metasenv' context' t1')) ; debug_print ("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));
+debug_print ("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) 
                               )
-                             ~status:(proof',goal')
+                             (proof',goal')
                        | _ -> raise (ProofEngineTypes.Fail "Discriminate: ElimType False left more (or less) than one goal")
                      )    
             | _ -> raise (ProofEngineTypes.Fail "Discriminate: not a discriminable equality")