public function setFunction($sFunction, $sArgs, $sScript)
    {
        return $this->addCommand(
            array(
                'cmd' => 'sf',
                'func' => trim((string)$sFunction, " \t"),
                'prop' => trim((string)$sArgs, " \t")
            ),
            trim((string)$sScript, " \t\n")
        );
    }