private static function setLineIfPrevious(&$line)
    {
        static $previousLine = '';

        if ($previousLine) {
            $line = $previousLine.' '.trim($line);
            $previousLine = '';
        }

        if (preg_match('/(.+)\\\$/', $line, $container)) {
            $previousLine = $container[1];
        }

        return $previousLine;
    }