Natools

   overriding procedure Next
     (Object : in out Cursor;
      Event : out Events.Event) is
   begin
      if Object.Position = null then
         Event := Events.Error;
         Event := Events.End_Of_Input;
         return;
      end if;

      if Object.Opening then
         pragma Assert (Object.Position.Kind = List_Node);
         if Object.Position.Child = null then
            Object.Opening := False;