As Jesse Donat mentioned the type will be infered automatically. To enforce some type you can use the callback facility like this:<?phpfunction cb_yaml_date($value, $tag, $flags) { return new DateTime($value);}$yaml = <<<YAMLevent1: name: My Event date: !date 25.05.2001YAML;$ndocs = 0;$data = yaml_parse($yaml, 0, $ndocs, array('!date' => 'cb_yaml_date'));print_r($data);?>The above example will output something similar to: Array ( [event1] => Array ( [name] => My Event [date] => DateTime Object ( [date] => 2001-05-25 00:00:00 [timezone_type] => 3 [timezone] => Europe/Berlin ) ) )BTW if you want to have large numbers you are probably using BC Math. Thus, you simple enclose your number in quotes:<?php$yaml = <<<YAMLlargenumber: '14695760472279668267313200104308'YAML;?>