I have to rectify my earlier words about the problems with the Zend Framework loadClass() method. Since posting this message I for a while did not have time to get a better look at this. Yesterday I posted my question about the Zend::loadClass() method to the Zend Framework mailinglist and pretty quickly I had a very useful response. On the train home, I decided to dive into the solution that was posted. And indeed. I had misunderstood the intention.
I was calling the method like this:
Zend::loadClass('Filter'); or Zend::loadClass('Filter', 'Zend'); or even Zend::loadClass('Zend_Filter', 'Zend'); and also Zend::loadClass('Filter', array('Zend'));
This last one after I finally found out the second parameter is meant to be an array. After I found out about that, I tried all combinations with the second parameter being an array but couldn't get it to work. But I was making it harder than I needed to, because it will work as simple as this:
This will work as long as the library directory (the directory where Zend.php is located) is in your include_path.
A classic case of RTFM, because I did read the documentation: