X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_tactics%2FnTactics.ml;h=67568154088e1d54f47c7b6de7662044166354ce;hb=81e3d11cbb2a7a6498b4b19876bbb5ababc8942b;hp=10fa168d492517123eff7b4b18861cb9827cfa47;hpb=2dd6e8f11fa3ac2995f326ecb742d9b4e8948fce;p=helm.git

diff --git a/helm/software/components/ng_tactics/nTactics.ml b/helm/software/components/ng_tactics/nTactics.ml
index 10fa168d4..675681540 100644
--- a/helm/software/components/ng_tactics/nTactics.ml
+++ b/helm/software/components/ng_tactics/nTactics.ml
@@ -46,13 +46,14 @@ let dot_tac status =
    status#set_stack gstatus
 ;;
 
-let branch_tac status =
+let branch_tac ?(force=false) status =
   let gstatus = 
     match status#stack with
     | [] -> assert false
     | (g, t, k, tag) :: s ->
           match init_pos g with (* TODO *)
-          | [] | [ _ ] -> fail (lazy "too few goals to branch")
+          | [] -> fail (lazy "empty goals")
+	  | [_] when (not force) -> fail (lazy "too few goals to branch")
           | loc :: loc_tl ->
                ([ loc ], [], [], `BranchTag) :: (loc_tl, t, k, tag) :: s
   in
@@ -644,10 +645,33 @@ let assert_tac seqs status =
        | [seq] -> assert0_tac seq
        | _ ->
          block_tac
-          (branch_tac::
+          ((branch_tac ~force:false)::
           HExtlib.list_concat ~sep:[shift_tac]
             (List.map (fun seq -> [assert0_tac seq]) seqs)@
           [merge_tac])
      ) status
 ;;
 
+let inversion_tac ~what:(txt,len,what) ~where = 
+  let what = txt, len, Ast.Appl [what; Ast.Implicit `Vector] in
+  let indtyinfo = ref None in
+  let sort = ref (NCic.Rel 1) in
+  atomic_tac (block_tac [
+    analyze_indty_tac ~what indtyinfo;    
+    (fun s -> select_tac 
+      ~where ~job:(`Substexpand ((HExtlib.unopt !indtyinfo).rightno+1)) true s);
+    sort_of_goal_tac sort;
+    (fun status ->
+     let ity = HExtlib.unopt !indtyinfo in
+     let NReference.Ref (uri, _) = ity.reference in
+     let name = 
+       NUri.name_of_uri uri ^ "_inv_" ^
+        snd (NCicElim.ast_of_sort 
+          (match !sort with NCic.Sort x -> x | _ -> assert false))
+     in
+     let eliminator = 
+       let _,_,w = what in
+       Ast.Appl [ Ast.Ident (name,None) ; Ast.Implicit `Vector ; w ]
+     in
+     exact_tac ("",0,eliminator) status) ]) 
+;;