YamlInline::getTimestampRegex PHP Method

    protected static function getTimestampRegex()
    {
        return <<<EOF
    ~^
    (?P<year>[0-9][0-9][0-9][0-9])
    -(?P<month>[0-9][0-9]?)
    -(?P<day>[0-9][0-9]?)
    (?:(?:[Tt]|[ \t]+)
    (?P<hour>[0-9][0-9]?)
    :(?P<minute>[0-9][0-9])
    :(?P<second>[0-9][0-9])
    (?:\\.(?P<fraction>[0-9]*))?
    (?:[ \t]*(?P<tz>Z|(?P<tz_sign>[-+])(?P<tz_hour>[0-9][0-9]?)
    (?::(?P<tz_minute>[0-9][0-9]))?))?)?
    \$~x
EOF;
    }