PHP provides two built-in functions to retrieve properties of a given class '" get_object_vars and get_class_vars. Both these functions behave the same exact way, one taking an object as a variable and the other taking a string class name. The tricky thing about the two functions is that they behave differently depending on the call scope, returning all of the class variables available within the called scope.

As a bit of a hack (in lower than PHP 5.3) he shows how to use the create_function function to create a small statement in a different scope that returns the only the variables seen from the "outside" - just the public ones. PHP 5.3 users can do it much more cleanly with closures. Code examples for both are included.

In the short post she lists just a few of the issues surrounding the use of the function including that it:

• is prone to critical abuse by user-supplied code
• skips opcode cache optimizations
• encourages not using comments (evil)
• 100% blind to reflection or PHPDoc style documentation generation

His name is 'create_function' and he's a really useful co-worker. For those of you who just vaguely know him - don't worry, he's not so much like his ev(a|i)l cousin. Well, that doesn't mean he can't be harmful, but he's more likely to help you instead.

To show why he's such a good friend, Felix includes some example code to help solve a fictional problem of a manager wanting to filter down the information about a few perspective programmers. The create_function function gives the code the ability to run various bits of code (like a call to in_array or counting the values in an array).

I should just get this straight right off the bat: you can't really do much functional programing in PHP. Functions are not first class citizens and the equivalent of passing functions around is passing around strings or arrays and relying on convention. No really.

He goes on by illustrating the point that PHP can do this sort of thing but only up to a point. Once you start to get into anonymous functions and moving past things like the array_map function, you start to loose a foothold. The create_function function allows for a bit more flexibility, but still doesn't fulfill the requirements needed for full support.