anchor.diff:  -export([ rename_fun/5, rename_var/5, rename_mod/3, generalise/7, move_fun/6, tuple_to_record/8,
            duplicated_code_in_buffer/3, duplicated_code_in_dirs/3, expression_search/5, fun_extraction/6, fold_expression/3, tuple_funpar/5,
   	 instrument_prog/2, uninstrument_prog/2, add_a_tag/5,register_pid/7, fun_to_process/5,
  -         undo/0, start_undo_process/0, stop_undo_process/0, undo_init/0]).
  +	 start_processes/1, stop_processes/0, error_logger/1,
  +         undo/0, undo_init/0]).
   
   
   rename_var(Fname, Line, Col, NewName, SearchPaths) ->
       case check_undo_process() of
  -	ok -> wrangler:rename_var(Fname, Line, Col, NewName, SearchPaths);
  +	ok -> Res=wrangler:rename_var(Fname, Line, Col, NewName, SearchPaths),
  +	      case Res of 
  +		  {ok, _} ->
  +		      check_error_logger();
  +		  {error, _} -> ok
  +	      end,
  +	      Res;		
   	{error, Reason} ->
   	    {error, Reason}
       end.
  
positive.code: 		       undo_loop(lists:sublist(History1,15)); %%KEEP 15 HISTORY VERSIONS. IS THIS ENOUGH?
  	stop -> ok    
      end.
  		       
  
negative.code: 	{refactor_undo, Reply} ->
  	    Reply
      end.
      
  
  start_processes(SearchPaths) ->
      start_undo_process(),
      start_error_logger(),
      refac_ast_server:start_ast_server(SearchPaths).
      
  stop_processes() ->
      stop_undo_process(),
      unregister(refactor_undo),
      stop_error_logger(),
      unregister(error_logger),
      refac_ast_server:stop_ast_server(),
      unregister(ast_server).
  
      
  start_undo_process() ->
      spawn_link(wrangler_distel, undo_init, []).
  