_MarkdownExtra_TmpImpl::doExtraAttributes PHP Method

    protected function doExtraAttributes($tag_name, $attr)
    {
        #
        # Parse attributes caught by the $this->id_class_attr_catch_re expression
        # and return the HTML-formatted list of attributes.
        #
        # Currently supported attributes are .class and #id.
        #
        if (empty($attr)) {
            return "";
        }
        # Split on components
        preg_match_all('/[#.a-z][-_:a-zA-Z0-9=]+/', $attr, $matches);
        $elements = $matches[0];
        # handle classes and ids (only first id taken into account)
        $classes = array();
        $attributes = array();
        $id = false;
        foreach ($elements as $element) {
            if ($element[0] == '.') {
                $classes[] = substr($element, 1);
            } elseif ($element[0] == '#') {
                if ($id === false) {
                    $id = substr($element, 1);
                }
            } elseif (strpos($element, '=') > 0) {
                $parts = explode('=', $element, 2);
                $attributes[] = $parts[0] . '="' . $parts[1] . '"';
            }
        }
        # compose attributes as string
        $attr_str = "";
        if (!empty($id)) {
            $attr_str .= ' id="' . $id . '"';
        }
        if (!empty($classes)) {
            $attr_str .= ' class="' . implode(" ", $classes) . '"';
        }
        if (!$this->no_markup && !empty($attributes)) {
            $attr_str .= ' ' . implode(" ", $attributes);
        }
        return $attr_str;
    }