> It is 12 years old - these were just before the first versions that had any kind of serious OO capability
PHP5 is the release where most of the OO improvements happened (but even PHP 4.3 had a bunch) and PHP 5.0 was released 3+ years before this code snippet leaked.
I wrote a heavily OO based version of Yahoo! Address Book using PHP 5.1 in 2005-2006, so it was definitely doable and fairly common to do so by that time.
PHP5 is the release where most of the OO improvements happened (but even PHP 4.3 had a bunch) and PHP 5.0 was released 3+ years before this code snippet leaked.
I wrote a heavily OO based version of Yahoo! Address Book using PHP 5.1 in 2005-2006, so it was definitely doable and fairly common to do so by that time.