anchor.diff:      case Initializer(Port) of
           ok ->
               {ok, Port};
  -        Error ->
  +        {error, Error} ->
               error_logger:error_report(Error),
               throw({error, init_failed})
       end;
  
positive.code:     case InitMod:InitFun(Port) of
          ok ->
              {ok, Port};
          Error ->
              error_logger:error_report(Error),
              throw({error, init_failed})
      end.
  
negative.code:         {error, ErrorJson} when is_binary(ErrorJson) ->
              {struct, [{<<"error">>, {struct, Error}}]} = mochijson2:decode(ErrorJson),
              {error, Error};
          ok ->
              ok
      end.
  
  eval_js(Ctx, Js) ->
  