Natools

      Previous_Level : constant Natural
        := Lockable.Current_Level (Object.Stack);
   begin
      Lockable.Pop_Level (Object.Stack, State);
      State := Lockable.Null_State;
      Object.Locked := False;

      if Finish then
      if Finish and Object.Position /= null then
         declare
            Event : Events.Event := Object.Current_Event;
         begin
         if Object.Position.Kind = List_Node and then Object.Opening then
            Object.Opening := False;
            loop
               case Event is
                  when Events.Add_Atom | Events.Open_List =>
                     null;
         end if;
         pragma Assert (not Object.Opening);

                  when Events.Close_List =>
                     exit when Object.Absolute_Level < Previous_Level;
         for I in 1 .. Object.Absolute_Level - Previous_Level + 1 loop
                  when Events.Error | Events.End_Of_Input =>
                     exit;
               end case;
               Object.Next (Event);
            end loop;
            Object.Position := Object.Position.Parent;
         end loop;
         end;
      end if;

      Object.Locked
        := Object.Absolute_Level < Lockable.Current_Level (Object.Stack);
   end Unlock;

end Natools.S_Expressions.Generic_Caches;