X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Ftactics%2FprimitiveTactics.ml;h=6646157240d93ab648ed54386908b03b51da1a28;hb=acc9067d3263ffced81c52539f918d47d418d5c7;hp=5fb8d4ae1eb56f88522cb14133c1a7c846a60e69;hpb=873f8a47b13fbf07df383f3b95d0f4994d2ce136;p=helm.git

diff --git a/helm/software/components/tactics/primitiveTactics.ml b/helm/software/components/tactics/primitiveTactics.ml
index 5fb8d4ae1..664615724 100644
--- a/helm/software/components/tactics/primitiveTactics.ml
+++ b/helm/software/components/tactics/primitiveTactics.ml
@@ -25,12 +25,12 @@
 
 (* $Id$ *)
 
-open ProofEngineHelpers
 open ProofEngineTypes
 
 exception TheTypeOfTheCurrentGoalIsAMetaICannotChooseTheRightElimiantionPrinciple
 exception NotAnInductiveTypeToEliminate
 exception WrongUriToVariable of string
+exception NotAnEliminator
 
 (* lambda_abstract newmeta ty *)
 (* returns a triple [bo],[context],[ty'] where              *)
@@ -41,7 +41,7 @@ exception WrongUriToVariable of string
 (* howmany = -1 means Intros, howmany > 0 means Intros n    *)
 let lambda_abstract ?(howmany=(-1)) metasenv context newmeta ty mk_fresh_name =
  let module C = Cic in
-  let rec collect_context context howmany ty =
+  let rec collect_context context howmany do_whd ty =
    match howmany with
    | 0 ->  
         let irl =
@@ -50,16 +50,16 @@ let lambda_abstract ?(howmany=(-1)) metasenv context newmeta ty mk_fresh_name =
          context, ty, (C.Meta (newmeta,irl))
    | _ -> 
       match ty with 
-        C.Cast (te,_)   -> collect_context context howmany te 
+        C.Cast (te,_)   -> collect_context context howmany do_whd te 
       | C.Prod (n,s,t)  ->
          let n' = mk_fresh_name metasenv context n ~typ:s in
           let (context',ty,bo) =
-           collect_context ((Some (n',(C.Decl s)))::context) (howmany - 1) t 
+           collect_context ((Some (n',(C.Decl s)))::context) (howmany - 1) do_whd t 
           in
            (context',ty,C.Lambda(n',s,bo))
       | C.LetIn (n,s,t) ->
          let (context',ty,bo) =
-          collect_context ((Some (n,(C.Def (s,None))))::context) (howmany - 1) t
+          collect_context ((Some (n,(C.Def (s,None))))::context) (howmany - 1) do_whd t
          in
           (context',ty,C.LetIn(n,s,bo))
       | _ as t ->
@@ -68,10 +68,13 @@ let lambda_abstract ?(howmany=(-1)) metasenv context newmeta ty mk_fresh_name =
           CicMkImplicit.identity_relocation_list_for_metavariable context
          in
           context, t, (C.Meta (newmeta,irl))
-        else
+        else if do_whd then
+	  let t = CicReduction.whd ~delta:true context t in
+	  collect_context context howmany false t
+	else
          raise (Fail (lazy "intro(s): not enough products or let-ins"))
   in
-   collect_context context howmany ty 
+   collect_context context howmany true ty 
 
 let eta_expand metasenv context t arg =
  let module T = CicTypeChecker in
@@ -232,7 +235,8 @@ let
 
 let new_metasenv_and_unify_and_t newmeta' metasenv' context term' ty termty goal_arity =
   let (consthead,newmetasenv,arguments,_) =
-   saturate_term newmeta' metasenv' context termty goal_arity in
+   TermUtil.saturate_term newmeta' metasenv' context termty
+    goal_arity in
   let subst,newmetasenv',_ = 
    CicUnification.fo_unif newmetasenv context consthead ty CicUniv.empty_ugraph
   in
@@ -246,14 +250,14 @@ let rec count_prods context ty =
     Cic.Prod (n,s,t) -> 1 + count_prods (Some (n,Cic.Decl s)::context) t
   | _ -> 0
 
-let apply_tac_verbose_with_subst ~term (proof, goal) =
+let apply_with_subst ~term ~subst ~maxmeta (proof, goal) =
   (* Assumption: The term "term" must be closed in the current context *)
  let module T = CicTypeChecker in
  let module R = CicReduction in
  let module C = Cic in
-  let (_,metasenv,_,_) = proof in
+  let (_,metasenv,_,_, _) = proof in
   let metano,context,ty = CicUtil.lookup_meta goal metasenv in
-  let newmeta = new_meta_of_proof ~proof in
+  let newmeta = max (CicMkImplicit.new_meta metasenv subst) maxmeta in
    let exp_named_subst_diff,newmeta',newmetasenvfragment,term' =
     match term with
        C.Var (uri,exp_named_subst) ->
@@ -318,27 +322,28 @@ let apply_tac_verbose_with_subst ~term (proof, goal) =
      CicMetaSubst.apply_subst ((metano,(context,bo',Cic.Implicit None))::subst)
    in
    let (newproof, newmetasenv''') = 
-     subst_meta_and_metasenv_in_proof proof metano subst_in newmetasenv''
+    ProofEngineHelpers.subst_meta_and_metasenv_in_proof proof metano subst_in
+     newmetasenv''
    in
-   (((metano,(context,bo',Cic.Implicit None))::subst)(* subst_in *), (* ALB *)
-    (newproof, 
-     List.map (function (i,_,_) -> i) new_uninstantiatedmetas))
+   let subst = ((metano,(context,bo',Cic.Implicit None))::subst) in
+   subst,
+   (newproof, List.map (function (i,_,_) -> i) new_uninstantiatedmetas),
+   max maxmeta (CicMkImplicit.new_meta newmetasenv''' subst)
 
 
 (* ALB *)
-let apply_tac_verbose_with_subst ~term status =
+let apply_with_subst ~term ?(subst=[]) ?(maxmeta=0) status =
   try
 (*     apply_tac_verbose ~term status *)
-    apply_tac_verbose_with_subst ~term status
+    apply_with_subst ~term ~subst ~maxmeta status
       (* TODO cacciare anche altre eccezioni? *)
   with 
   | CicUnification.UnificationFailure msg
-  | CicTypeChecker.TypeCheckerFailure msg ->
-      raise (Fail msg)
+  | CicTypeChecker.TypeCheckerFailure msg -> raise (Fail msg)
 
 (* ALB *)
 let apply_tac_verbose ~term status =
-  let subst, status = apply_tac_verbose_with_subst ~term status in
+  let subst, status, _ = apply_with_subst ~term status in
   (CicMetaSubst.apply_subst subst), status
 
 let apply_tac ~term status = snd (apply_tac_verbose ~term status)
@@ -364,14 +369,15 @@ let intros_tac ?howmany ?(mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_
  =
   let module C = Cic in
   let module R = CicReduction in
-   let (_,metasenv,_,_) = proof in
+   let (_,metasenv,_,_, _) = proof in
    let metano,context,ty = CicUtil.lookup_meta goal metasenv in
-    let newmeta = new_meta_of_proof ~proof in
+    let newmeta = ProofEngineHelpers.new_meta_of_proof ~proof in
      let (context',ty',bo') =
       lambda_abstract ?howmany metasenv context newmeta ty mk_fresh_name_callback
      in
       let (newproof, _) =
-        subst_meta_in_proof proof metano bo' [newmeta,context',ty']
+       ProofEngineHelpers.subst_meta_in_proof proof metano bo'
+        [newmeta,context',ty']
       in
        (newproof, [newmeta])
  in
@@ -383,9 +389,9 @@ let cut_tac ?(mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_name ~subst:
   term (proof, goal)
  =
   let module C = Cic in
-   let curi,metasenv,pbo,pty = proof in
+   let curi,metasenv,pbo,pty, attrs = proof in
    let metano,context,ty = CicUtil.lookup_meta goal metasenv in
-    let newmeta1 = new_meta_of_proof ~proof in
+    let newmeta1 = ProofEngineHelpers.new_meta_of_proof ~proof in
     let newmeta2 = newmeta1 + 1 in
     let fresh_name =
      mk_fresh_name_callback metasenv context (Cic.Name "Hcut") ~typ:term in
@@ -405,7 +411,7 @@ let cut_tac ?(mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_name ~subst:
         C.Meta (newmeta2,irl2)]
      in
       let (newproof, _) =
-       subst_meta_in_proof proof metano bo'
+       ProofEngineHelpers.subst_meta_in_proof proof metano bo'
         [newmeta2,context,term; newmeta1,context_for_newmeta1,newmeta1ty];
       in
        (newproof, [newmeta1 ; newmeta2])
@@ -418,11 +424,20 @@ let letin_tac ?(mk_fresh_name_callback=FreshNamesGenerator.mk_fresh_name ~subst:
   term (proof, goal)
  =
   let module C = Cic in
-   let curi,metasenv,pbo,pty = proof in
+   let curi,metasenv,pbo,pty, attrs = proof in
+   (* occur check *)
+   let occur i t =
+     let m = CicUtil.metas_of_term t in 
+     List.exists (fun (j,_) -> i=j) m
+   in
    let metano,context,ty = CicUtil.lookup_meta goal metasenv in
-    let _,_ = (* TASSI: FIXME *)
+   if occur metano term then
+     raise 
+       (ProofEngineTypes.Fail (lazy
+         "You can't letin a term containing the current goal"));
+    let _,_ =
       CicTypeChecker.type_of_aux' metasenv context term CicUniv.empty_ugraph in
-     let newmeta = new_meta_of_proof ~proof in
+     let newmeta = ProofEngineHelpers.new_meta_of_proof ~proof in
      let fresh_name =
       mk_fresh_name_callback metasenv context (Cic.Name "Hletin") ~typ:term in
      let context_for_newmeta =
@@ -434,7 +449,7 @@ let letin_tac ?(mk_fresh_name_callback=FreshNamesGenerator.mk_fresh_name ~subst:
       let newmetaty = CicSubstitution.lift 1 ty in
       let bo' = C.LetIn (fresh_name,term,C.Meta (newmeta,irl)) in
        let (newproof, _) =
-         subst_meta_in_proof
+         ProofEngineHelpers.subst_meta_in_proof
            proof metano bo'[newmeta,context_for_newmeta,newmetaty]
        in
         (newproof, [newmeta])
@@ -445,7 +460,7 @@ let letin_tac ?(mk_fresh_name_callback=FreshNamesGenerator.mk_fresh_name ~subst:
 let exact_tac ~term =
  let exact_tac ~term (proof, goal) =
   (* Assumption: the term bo must be closed in the current context *)
-  let (_,metasenv,_,_) = proof in
+  let (_,metasenv,_,_, _) = proof in
   let metano,context,ty = CicUtil.lookup_meta goal metasenv in
   let module T = CicTypeChecker in
   let module R = CicReduction in
@@ -454,7 +469,7 @@ let exact_tac ~term =
   if b then
    begin
     let (newproof, metasenv') =
-      subst_meta_in_proof proof metano term [] in
+      ProofEngineHelpers.subst_meta_in_proof proof metano term [] in
     (newproof, [])
    end
   else
@@ -463,18 +478,34 @@ let exact_tac ~term =
   mk_tactic (exact_tac ~term)
 
 (* not really "primitive" tactics .... *)
-let elim_tac ~term = 
- let elim_tac ~term (proof, goal) =
-  let module T = CicTypeChecker in
-  let module U = UriManager in
-  let module R = CicReduction in
-  let module C = Cic in
-   let (curi,metasenv,proofbo,proofty) = proof in
-   let metano,context,ty = CicUtil.lookup_meta goal metasenv in
-    let termty,_ = T.type_of_aux' metasenv context term CicUniv.empty_ugraph in
+  
+module TC  = CicTypeChecker
+module U   = UriManager
+module R   = CicReduction
+module C   = Cic
+module PET = ProofEngineTypes
+module PEH = ProofEngineHelpers
+module PER = ProofEngineReduction
+module MS  = CicMetaSubst 
+module S   = CicSubstitution 
+module T   = Tacticals
+module RT  = ReductionTactics
+
+let elim_tac ?using ?(pattern = PET.conclusion_pattern None) term = 
+ let elim_tac (proof, goal) =
+   let ugraph = CicUniv.empty_ugraph in
+   let curi, metasenv, proofbo, proofty, attrs = proof in
+   let conjecture = CicUtil.lookup_meta goal metasenv in
+   let metano, context, ty = conjecture in
+(*    let (term, metasenv, _ugraph), cpatt = match pattern with 
+       | Some f, [], Some cpatt -> f context metasenv ugraph, cpatt
+       | _                      -> assert false
+    in
+*)    
+    let termty,_ugraph = TC.type_of_aux' metasenv context term ugraph in
     let termty = CicReduction.whd context termty in
-    let (termty,metasenv',arguments,fresh_meta) =
-     ProofEngineHelpers.saturate_term
+    let (termty,metasenv',arguments,_fresh_meta) =
+     TermUtil.saturate_term
       (ProofEngineHelpers.new_meta_of_proof proof) metasenv context termty 0 in
     let term = if arguments = [] then term else Cic.Appl (term::arguments) in
     let uri,exp_named_subst,typeno,args =
@@ -487,14 +518,14 @@ let elim_tac ~term =
      let eliminator_uri =
       let buri = U.buri_of_uri uri in
       let name = 
-        let o,_ = CicEnvironment.get_obj CicUniv.empty_ugraph uri in
+        let o,_ugraph = CicEnvironment.get_obj ugraph uri in
        match o with
           C.InductiveDefinition (tys,_,_,_) ->
            let (name,_,_,_) = List.nth tys typeno in
             name
         | _ -> assert false
       in
-      let ty_ty,_ = T.type_of_aux' metasenv' context ty CicUniv.empty_ugraph in
+      let ty_ty,_ugraph = TC.type_of_aux' metasenv' context ty ugraph in
       let ext =
        match ty_ty with
           C.Sort C.Prop -> "_ind"
@@ -506,59 +537,213 @@ let elim_tac ~term =
       in
        U.uri_of_string (buri ^ "/" ^ name ^ ext ^ ".con")
      in
-      let eliminator_ref = C.Const (eliminator_uri,exp_named_subst) in
-       let ety,_ = 
-         T.type_of_aux' metasenv' context eliminator_ref CicUniv.empty_ugraph in
-        let rec find_args_no =
-         function
-            C.Prod (_,_,t) -> 1 + find_args_no t
-          | C.Cast (s,_) -> find_args_no s
-          | C.LetIn (_,_,t) -> 0 + find_args_no t
-          | _ -> 0
-        in
-         let args_no = find_args_no ety in
-         let term_to_refine =
-          let rec make_tl base_case =
-           function
-              0 -> [base_case]
-            | n -> (C.Implicit None)::(make_tl base_case (n - 1))
-          in
-           C.Appl (eliminator_ref :: make_tl term (args_no - 1))
+      let eliminator_ref = match using with
+         | None   -> C.Const (eliminator_uri,exp_named_subst)
+         | Some t -> t 
+       in
+       let ety,_ugraph = 
+         TC.type_of_aux' metasenv' context eliminator_ref ugraph in
+(* FG: ADDED PART ***********************************************************)
+(* FG: we can not assume eliminator is the default eliminator ***************)
+   let add_lambdas n t =
+      let rec aux n t =
+         if n <= 0 then t 
+	 else C.Lambda (C.Anonymous, C.Implicit None, aux (pred n) t)
+      in
+      aux n (S.lift n t)
+   in
+   let rec args_init n f =
+      if n <= 0 then [] else f n :: args_init (pred n) f
+   in
+   let splits, args_no = PEH.split_with_whd (context, ety) in
+   let pred_pos = match List.hd splits with
+      | _, C.Rel i when i > 1 && i <= args_no -> i
+      | _, C.Appl (C.Rel i :: _) when i > 1 && i <= args_no -> i
+      | _ -> raise NotAnEliminator
+   in
+   let _, lambdas = PEH.split_with_whd (List.nth splits pred_pos) in
+   let termty_ty =
+      let termty_ty,_ugraph = TC.type_of_aux' metasenv' context termty ugraph in
+      CicReduction.whd context termty_ty
+   in
+(*   
+   let metasenv', term, pred, upto = match cpatt, termty_ty with
+      | C.Implicit (Some `Hole), _ 
+      | _, C.Sort C.Prop when lambdas = 0 -> metasenv', term, C.Implicit None, 0
+      | _                                 ->
+(* FG: we find the predicate for the eliminator as in the rewrite tactic ****)
+         let fresh_name = 
+             FreshNamesGenerator.mk_fresh_name 
+             ~subst:[] metasenv' context C.Anonymous ~typ:termty
+         in
+         let lazy_term c m u =  
+            let distance  = List.length c - List.length context in
+            S.lift distance term, m, u
          in
-          let refined_term,_,metasenv'',_ = 
+         let pattern = Some lazy_term, [], Some cpatt in
+         let subst, metasenv', _ugraph, _conjecture, selected_terms =
+            ProofEngineHelpers.select
+            ~metasenv:metasenv' ~ugraph ~conjecture ~pattern
+         in
+         let metasenv' = MS.apply_subst_metasenv subst metasenv' in  
+         let map (_context_of_t, t) l = t :: l in
+         let what = List.fold_right map selected_terms [] in
+         let ty = MS.apply_subst subst ty in
+         let term = MS.apply_subst subst term in
+         let termty = MS.apply_subst subst termty in
+         let abstr_ty = PER.replace_with_rel_1_from ~equality:(==) ~what 1 ty in
+         let abstr_ty = MS.apply_subst subst abstr_ty in
+         let pred_body = C.Lambda (fresh_name, termty, abstr_ty) in
+	 metasenv', term, add_lambdas (pred lambdas) pred_body, lambdas 
+   in
+(* FG: END OF ADDED PART ****************************************************)
+*)
+         let pred, upto = C.Implicit None, 0 in
+	 
+	 let term_to_refine =
+          let f n =
+	   if n = pred_pos then pred else
+	   if n = 1 then term else C.Implicit None
+	  in
+           C.Appl (eliminator_ref :: args_init args_no f)
+         in
+          let refined_term,_refined_termty,metasenv'',_ugraph = 
            CicRefine.type_of_aux' metasenv' context term_to_refine
-             CicUniv.empty_ugraph
+             ugraph
           in
            let new_goals =
             ProofEngineHelpers.compare_metasenvs
              ~oldmetasenv:metasenv ~newmetasenv:metasenv''
            in
-           let proof' = curi,metasenv'',proofbo,proofty in
+           let proof' = curi,metasenv'',proofbo,proofty, attrs in
             let proof'', new_goals' =
-             apply_tactic (apply_tac ~term:refined_term) (proof',goal)
+	     apply_tactic (apply_tac ~term:refined_term) (proof',goal)
             in
              (* The apply_tactic can have closed some of the new_goals *)
              let patched_new_goals =
-              let (_,metasenv''',_,_) = proof'' in
+              let (_,metasenv''',_,_, _) = proof'' in
                List.filter
                 (function i -> List.exists (function (j,_,_) -> j=i) metasenv'''
                 ) new_goals @ new_goals'
              in
-              proof'', patched_new_goals
+              let res = proof'', patched_new_goals in
+               if upto = 0 then res else 
+		let pattern = PET.conclusion_pattern None in
+	        let continuation =
+		 RT.simpl_tac ~pattern
+		 (* RT.head_beta_reduce_tac ~delta:false ~upto ~pattern *)
+		in
+		 let dummy_status = proof,goal in
+		  PET.apply_tactic
+		   (T.then_ ~start:(PET.mk_tactic (fun _ -> res)) ~continuation)
+                   dummy_status
  in
-  mk_tactic (elim_tac ~term)
+  mk_tactic elim_tac
 ;;
 
+let cases_intros_tac ?(mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_name ~subst:[]) term =
+ let cases_tac ~term (proof, goal) =
+  let module TC = CicTypeChecker in
+  let module U = UriManager in
+  let module R = CicReduction in
+  let module C = Cic in
+   let (curi,metasenv,proofbo,proofty, attrs) = proof in
+   let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+    let termty,_ = TC.type_of_aux' metasenv context term CicUniv.empty_ugraph in
+    let termty = CicReduction.whd context termty in
+    let (termty,metasenv',arguments,fresh_meta) =
+     TermUtil.saturate_term
+      (ProofEngineHelpers.new_meta_of_proof proof) metasenv context termty 0 in
+    let term = if arguments = [] then term else Cic.Appl (term::arguments) in
+    let uri,exp_named_subst,typeno,args =
+     match termty with
+        C.MutInd (uri,typeno,exp_named_subst) -> (uri,exp_named_subst,typeno,[])
+      | C.Appl ((C.MutInd (uri,typeno,exp_named_subst))::args) ->
+          (uri,exp_named_subst,typeno,args)
+      | _ -> raise NotAnInductiveTypeToEliminate
+    in
+     let paramsno,itty,patterns =
+      match CicEnvironment.get_obj CicUniv.empty_ugraph uri with
+         C.InductiveDefinition (tys,_,paramsno,_),_ ->
+          let _,_,itty,cl = List.nth tys typeno in
+          let rec aux n context t =
+           match n,CicReduction.whd context t with
+              0,C.Prod (name,source,target) ->
+               let fresh_name =
+                mk_fresh_name_callback metasenv' context name
+                 (*CSC: WRONG TYPE HERE: I can get a "bad" name*)
+                 ~typ:source
+               in
+                C.Lambda (fresh_name,C.Implicit None,
+                 aux 0 (Some (fresh_name,C.Decl source)::context) target)
+            | n,C.Prod (name,source,target) ->
+               let fresh_name =
+                mk_fresh_name_callback metasenv' context name
+                 (*CSC: WRONG TYPE HERE: I can get a "bad" name*)
+                 ~typ:source
+               in
+                aux (n-1) (Some (fresh_name,C.Decl source)::context) target
+            | 0,_ -> C.Implicit None
+            | _,_ -> assert false
+          in
+           paramsno,itty,
+           List.map (function (_,cty) -> aux paramsno context cty) cl 
+       | _ -> assert false
+     in
+      let outtype =
+       let target =
+        C.Lambda (C.Name "fixme",C.Implicit None,
+         ProofEngineReduction.replace_lifting
+          ~equality:(ProofEngineReduction.alpha_equivalence)
+          ~what:[CicSubstitution.lift (paramsno+1) term]
+          ~with_what:[C.Rel (paramsno+1)]
+          ~where:(CicSubstitution.lift (paramsno+1) ty))
+       in
+        let rec add_lambdas =
+         function
+            0 -> target
+          | n -> C.Lambda (C.Name "fixme",C.Implicit None,add_lambdas (n-1))
+        in
+         add_lambdas (count_prods context itty - paramsno)
+      in
+       let term_to_refine =
+        C.MutCase (uri,typeno,outtype,term,patterns)
+       in
+        let refined_term,_,metasenv'',_ = 
+         CicRefine.type_of_aux' metasenv' context term_to_refine
+           CicUniv.empty_ugraph
+        in
+         let new_goals =
+          ProofEngineHelpers.compare_metasenvs
+           ~oldmetasenv:metasenv ~newmetasenv:metasenv''
+         in
+         let proof' = curi,metasenv'',proofbo,proofty, attrs in
+          let proof'', new_goals' =
+           apply_tactic (apply_tac ~term:refined_term) (proof',goal)
+          in
+           (* The apply_tactic can have closed some of the new_goals *)
+           let patched_new_goals =
+            let (_,metasenv''',_,_,_) = proof'' in
+             List.filter
+              (function i -> List.exists (function (j,_,_) -> j=i) metasenv'''
+              ) new_goals @ new_goals'
+           in
+            proof'', patched_new_goals
+ in
+  mk_tactic (cases_tac ~term)
+;;
+
+
 let elim_intros_tac ?(mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_name ~subst:[]) 
-                    ?depth ?using what =
- Tacticals.then_ ~start:(elim_tac ~term:what)
+                    ?depth ?using ?pattern what =
+ Tacticals.then_ ~start:(elim_tac ?using ?pattern what)
   ~continuation:(intros_tac ~mk_fresh_name_callback ?howmany:depth ())
 ;;
 
 (* The simplification is performed only on the conclusion *)
 let elim_intros_simpl_tac ?(mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_name ~subst:[])
-                          ?depth ?using what =
- Tacticals.then_ ~start:(elim_tac ~term:what)
+                          ?depth ?using ?pattern what =
+ Tacticals.then_ ~start:(elim_tac ?using ?pattern what)
   ~continuation:
    (Tacticals.thens
      ~start:(intros_tac ~mk_fresh_name_callback ?howmany:depth ())
@@ -569,21 +754,19 @@ let elim_intros_simpl_tac ?(mk_fresh_name_callback = FreshNamesGenerator.mk_fres
 
 (* FG: insetrts a "hole" in the context (derived from letin_tac) *)
 
-module C = Cic
-
-let letout_tac () =
+let letout_tac =
    let mk_fresh_name_callback = FreshNamesGenerator.mk_fresh_name ~subst:[] in
    let term = C.Sort C.Set in
    let letout_tac (proof, goal) =
-      let curi, metasenv, pbo, pty = proof in
+      let curi, metasenv, pbo, pty, attrs = proof in
       let metano, context, ty = CicUtil.lookup_meta goal metasenv in
-      let newmeta = new_meta_of_proof ~proof in
+      let newmeta = ProofEngineHelpers.new_meta_of_proof ~proof in
       let fresh_name = mk_fresh_name_callback metasenv context (Cic.Name "hole") ~typ:term in
       let context_for_newmeta = None :: context in
       let irl = CicMkImplicit.identity_relocation_list_for_metavariable context_for_newmeta in
       let newmetaty = CicSubstitution.lift 1 ty in
       let bo' = C.LetIn (fresh_name, term, C.Meta (newmeta,irl)) in
-      let newproof, _ = subst_meta_in_proof proof metano bo'[newmeta,context_for_newmeta,newmetaty] in
+      let newproof, _ = ProofEngineHelpers.subst_meta_in_proof proof metano bo'[newmeta,context_for_newmeta,newmetaty] in
       newproof, [newmeta]
    in
    mk_tactic letout_tac