addElement('text', 'start', array( 'label' => 'Start', 'required' => true, 'description' => sprintf( $form->translate( 'Please see %s for detailled instructions of how start and and work' ), 'http://php.net/manual/en/function.substr.php' ) )); $form->addElement('text', 'length', array( 'label' => 'End', 'required' => true, )); } public function transform($value) { return substr($value, $this->getSetting('start'), $this->getSetting('length')); } }