public function _process($val, $map) {
		foreach ($map as $m => $arg) {
			if (is_numeric($m)) {
				$m = $arg;
				$arg = null;
			}

			if ($arg !== null) {
				$ret = call_user_func($m, $val, $arg);
			} else {
				$ret = call_user_func($m, $val);
			}

			if ($ret !== false) {
				$val = $ret;
			}
		}
		return $val;
	}