Parsedown::blockFencedCode( $Line )

    protected function blockFencedCode($Line)
    {
        $marker = $Line['text'][0];

        $openerLength = strspn($Line['text'], $marker);

        if ($openerLength < 3)
        {
            return;
        }

        $infostring = trim(substr($Line['text'], $openerLength), "\t ");

        if (strpos($infostring, '`') !== false)
        {
            return;
        }

        $Element = array(
            'name' => 'code',
            'text' => '',
        );

        if ($infostring !== '')
        {
            /**
             * https://www.w3.org/TR/2011/WD-html5-20110525/elements.html#classes
             * Every HTML element may have a class attribute specified.
             * The attribute, if specified, must have a value that is a set
             * of space-separated tokens representing the various classes
             * that the element belongs to.
             * [...]
             * The space characters, for the purposes of this specification,
             * are U+0020 SPACE, U+0009 CHARACTER TABULATION (tab),
             * U+000A LINE FEED (LF), U+000C FORM FEED (FF), and
             * U+000D CARRIAGE RETURN (CR).
             */
            $language = substr($infostring, 0, strcspn($infostring, " \t\n\f\r"));

            $Element['attributes'] = array('class' => "language-$language");
        }

        $Block = array(
            'char' => $marker,
            'openerLength' => $openerLength,
            'element' => array(
                'name' => 'pre',
                'element' => $Element,
            ),
        );

        return $Block;
    }