public function renderSourceFragment($lines, $errline)
    {
        $output = '<div class="info"><h3>Source</h3>';
        $output .= '<pre>';
        foreach ($lines as $offset => $line) {
            $line = htmlentities($line, ENT_COMPAT, 'UTF-8');
            if ($offset == $errline) {
                $output .= "<span>$offset</span> <span class=\"error\">$line</span>";
            } else {
                $output .= "<span>$offset</span> $line";
            }
        }
        $output .= '</pre></div>';

        return $output;
    }