private function parseQuotedString()
    {
        $string = '';
        $delimiter = $this->current;

        // Skip first delimiter
        $this->next();

        while ($this->valid()) {
            if ($delimiter === $this->current) {
                // Skip last delimiter
                $this->next();

                break;
            }

            if ('\\' === $this->current) {
                $string .= $this->parseEscapeSequence();
            } elseif ('"' === $this->current) {
                $string .= '"'.$this->parseQuotedString().'"';
            } elseif ("'" === $this->current) {
                $string .= "'".$this->parseQuotedString()."'";
            } else {
                $string .= $this->current;
                $this->next();
            }
        }

        return $string;
    }