Number notation for NG

diff --git a/helm/software/components/ng_cic_content/nTermCicContent.ml b/helm/software/components/ng_cic_content/nTermCicContent.ml
index e36a1290c949ed8bdc5549546228fb82efff9ea3..5cfda009c26bb564af3a45205860d931c320befb 100644 (file)
--- a/helm/software/components/ng_cic_content/nTermCicContent.ml
+++ b/helm/software/components/ng_cic_content/nTermCicContent.ml
@@ -64,6 +64,26 @@ let level_of_uri u =
   String.sub name 4 (String.length name - 4)
 ;;
 
+let destroy_nat =
+  let is_nat_URI = NUri.eq (NUri.uri_of_string
+  "cic:/matita/ng/arithmetics/nat/nat.ind") in
+  let is_zero = function
+    | NCic.Const (NReference.Ref (uri, NReference.Con (0, 1, 0))) when
+       is_nat_URI uri -> true
+    | _ -> false
+  in
+  let is_succ = function
+    | NCic.Const (NReference.Ref (uri, NReference.Con (0, 2, 0))) when
+       is_nat_URI uri -> true
+    | _ -> false
+  in
+  let rec aux acc = function
+    | NCic.Appl [he ; tl] when is_succ he -> aux (acc + 1) tl
+    | t when is_zero t -> Some acc
+    | _ -> None
+  in
+   aux 0
+
 (* CODICE c&p da NCicPp *)
 let nast_of_cic0 status
  ~(idref:
@@ -119,25 +139,29 @@ let nast_of_cic0 status
            | NCic.Appl l -> NCic.Appl (l@args)
            | _ -> NCic.Appl (hd :: args)))
     | NCic.Appl args as t ->
-       let args =
-        if not !Acic2content.hide_coercions then args
-        else
-         match
-          NCicCoercion.match_coercion status ~metasenv ~context ~subst t
-         with
-          | None -> args
-          | Some (_,sats,cpos) -> 
+       (match destroy_nat t with
+         | Some n -> idref (Ast.Num (string_of_int n, -1))
+         | None ->
+            let args =
+             if not !Acic2content.hide_coercions then args
+             else
+              match
+               NCicCoercion.match_coercion status ~metasenv ~context ~subst t
+              with
+               | None -> args
+               | Some (_,sats,cpos) -> 
 (* CSC: sats e' il numero di pi, ma non so cosa farmene! voglio il numero di
    argomenti da saltare, come prima! *)
-             if cpos < List.length args - 1 then
-              List.nth args (cpos + 1) ::
-               try snd (HExtlib.split_nth (cpos+sats+2) args) with Failure _->[]
-             else
-              args
-       in
-        (match args with
-            [arg] -> idref (k ~context arg)
-          | _ -> idref (Ast.Appl (List.map (k ~context) args)))
+                  if cpos < List.length args - 1 then
+                   List.nth args (cpos + 1) ::
+                    try snd (HExtlib.split_nth (cpos+sats+2) args)
+                    with Failure _->[]
+                  else
+                   args
+            in
+             (match args with
+                 [arg] -> idref (k ~context arg)
+               | _ -> idref (Ast.Appl (List.map (k ~context) args))))
     | NCic.Match (NReference.Ref (uri,_) as r,outty,te,patterns) ->
         let name = NUri.name_of_uri uri in
 (* CSC