If Mr. Nix is interested he will respond, thanks for posting your opinions on his code but it was merely an example likely based on a common template (in his mind or otherwise) he uses to demonstrate the more advanced features in the Zend-2 engine (OOP in PHP5) and everyone has their own naming conventions. Since it's a child class that extends another, conceptually, using an underscore is understandable to distinguish the parent_child relationship. I see your point on that, but I also fully comprehended Mr. Nix's concept based solely on his code without any guesswork or confusion. I'm not saying it could not be improved, that process could go on forever, of course.
-jim
-jim