anchor.diff:  % got undefined message with standart format
   -define(undefined(Arg),
           {current_function, {M, F, A}} = process_info(self(), current_function),
  -        RegisteredName = case process_info(self(), registered_name) of 
  +        RegisteredName = case process_info(self(), registered_name) of
               [] -> unregistered;
               {registered_name, Name} -> Name
           end,
  
positive.code: % got undefined message with custom format
  -define(undefined(Msg,Arg),
          {current_function, {M, F, A}} = process_info(self(), current_function),
          RegisteredName = case process_info(self(), registered_name) of 
              [] -> unregistered;
              {registered_name, Name} -> Name
          end,
  
negative.code:     ).
  -else.
      -define(here, true).
      -define(dump2file(Data, Filename), true).
      -define(debug(Msg), true).
      -define(debug(Msg,Arg), true).
  -endif.
  