Online PHP editor | output for WpBS5

<?php class SerialDateTime extends DateTime implements JsonSerializable{ public function jsonSerialize(){ return ['timestamp' => $this->getTimestamp()]; } public function __toString(){ return $this->getTimestamp(); } // TODO: Is this the best way, or is there a better way? public static function createFromFormat($f, $t, $tz=NULL){ $dateTime = call_user_func( array('SerialDateTime', 'parent::createFromFormat'), $f, $t, $tz ); $ret = new self(); return $ret->setTimestamp($dateTime->getTimestamp()); } } echo(strnatcasecmp(new SerialDateTime, new SerialDateTime('January 1, 2013'));