In response to this post on the ActsAsFlinn blog's comments on ActiveRecord in PHP, Arnold Daniels has some comments of his own on the subject - specifically about the need for more work on the object oriented side of things in PHP natively.

Today I read an article about how Active Record is implemented in Ruby. In this article he lays down how things are done in Ruby and how that is not possible on PHP. Though I agree with him on a large part, there are a few site notes to make here.

Arnold talks about a solution to an issue mentioned in the ActsAsFlinn blog - the addition of methods to a preexisting class - via the runkit extension. He gives a PHP translation of the Ruby code from the other post and includes a few proof of concepts to show it in action. You can download the code if you'd like to try it out yourself.

David Sklar points out an issue that keeps coming up over and over again in the course of object-oriented applications - why the static keyword doesn't know about inheritance.

There are plenty of good reasons why PHP 5 works this way and it seems that in PHP 6 the static keyword will be able to be used in place of self to get the dynamic behavior a lot of folks are looking for. [...] All well and good once PHP 6 is done.

In the meantime, I was noodling around with runkit and came up with some glue that lets you do something like this.

In his runkit example uses a glue class called MethodHelper that uses various things (including some reflection) to manually look into the classes and find the static information.

A fun proof of concept, but not something (for efficiency reasons) you'd probably want to run on a busy production site.

If you've ever really found a time when you needed to overwrite one of PHP's bult-in functions with your own custom one (maybe a custom handler or the like), you might want to check out this post on OpenIdeasCompany.com.

The author needed to redeclare session_start in a few files to change the place the default sessions are located at (spanned across three machines). He didn't want to rewrite the application to make this change, so he used the runkit extension out of pecl (and the php-devel package) to create a solution redefining functions to match his needs.

Of course, there are some easier ways to accomplish what he needed, but it's still an interesting method if there's really just no other way.