    public static function mod($vars)
    {
        switch (SMART_URL) {
            case true:
                # code...
                $inFold = (Options::v('permalink_use_index_php') == 'on') ? '/index.php' : '';
                $url = Site::$url.$inFold.'/mod/'.$vars.GX_URL_PREFIX;
                break;

            default:
                # code...
                $url = Site::$url."/?mod={$vars}";
                break;
        }

        return $url;
    }
The software constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component.