Although this is the "better" method, as no dirty hacks have to be made, it can be very frustrating as well as energy - and time-consuming, which is why we've decided on the direct approach.
Note that even though this chapter tries to impart as much knowledge as possible about the inner workings of PHP, it's impossible to really give a complete guide to extending PHP that works 100% of the time in all cases. PHP is such a huge and complex package that its inner workings can only be understood if you make yourself familiar with it by practicing, so we encourage you to work with the source.