anchor.diff:  
   -module(wrangler_distel).
   
  --export([ rename_fun/5, rename_var/5, rename_mod/3, generalise/7, move_fun/6, tuple_to_record/8,
  +-export([ rename_fun/5, rename_var/5, rename_mod/3, rename_process/5, 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,
  -	 start_processes/1, stop_processes/0, 
  -         undo/0]).
  +	 instrument_prog/2, uninstrument_prog/2, add_a_tag/5,register_pid/7, fun_to_process/5]).
  +	 
   
   -include("../hrl/wrangler.hrl").
   
  
positive.code: 	     {error, string()} | {ok, string()}).
  rename_var(Fname, Line, Col, NewName, SearchPaths) ->
      case check_undo_process() of
  	ok -> Res=wrangler:rename_var(Fname, Line, Col, NewName, SearchPaths),
  	      case Res of 
  		  {ok, _} ->
  		      check_wrangler_error_logger();
  		  {error, _} -> ok
  	      end,
  	      Res;		
  	{error, Reason} ->
  	    {error, Reason}
      end.
  
  -spec(rename_fun/5::(string(), integer(), integer(), string(), [dir()]) ->
  	     {error, string()} | {ok, [filename()]}).
  rename_fun(Fname, Line, Col, NewName,SearchPaths) ->
      case check_undo_process() of
  	ok -> wrangler:rename_fun(Fname, Line, Col, NewName,SearchPaths);
  	{error, Reason} ->
  	   {error, Reason}
      end.
  
  -spec(rename_mod/3::(filename(), string(), [dir()]) -> {error, string()} | {ok, [filename()]}).	  
  rename_mod(Fname, NewName,SearchPaths) ->
      case check_undo_process() of 
  	ok ->  wrangler:rename_mod(Fname, NewName,SearchPaths);
  	{error, Reason} ->
  	    {error, Reason}
      end.
  
negative.code:     end.
  
  -spec(fun_to_process/5::(filename(), integer(), integer(), string(), [dir()])->
  	     {error, string()} | undecidables | {ok, [filename()]}).
  fun_to_process(Fname, Line, Col, ProcessName,SearchPaths) ->
      case check_undo_process() of
  	ok -> Res = wrangler:fun_to_process(Fname, Line, Col, ProcessName,SearchPaths),
  	      case Res of 
  		  {ok, _} ->
  		      check_wrangler_error_logger();
  		  _ -> ok
  	      end,
  	      Res;
  	{error, Reason} ->
  	   {error, Reason}
      end.
  
  
  check_undo_process() ->
  