array( * 'groupname' => array( * 'type' => 'error' | 'warning', * 'message' => 'Dont use this one please!', * 'keys' => array( 'key1', 'another_key' ), * 'callback' => array( 'class', 'method' ), // Optional. * ) * ) * * @return array */ public function getGroups() { return array(); } /** * Callback to process each confirmed key, to check value. * * @param string $key Array index / key. * @param mixed $val Assigned value. * @param int $line Token line. * @param array $group Group definition. * @return mixed FALSE if no match, TRUE if matches, STRING if matches * with custom error message passed to ->process(). */ public function callback( $key, $val, $line, $group ) { return true; } }