Sean Coates has posted a new article today about one of the features that will be included in the next major release of PHP (5.3) - late static bindings.

Late Static Binding (LSB) is a topic that's been brought up numerous times in the past three years in various PHP development discussion circles (and we're finally getting it in PHP 5.3)'"but what does it really do, and why should you care? Here's a simple practical example of how it can greatly simplify your code's design.

He shows its usefulness in an example of how it works, letting classes/objects access static methods, constants and properties of inherited classes (besides their own). His example (using beer, of course) shows how an extended class (Ale) can reference the constant (NAME) in the parent class (Beer). Thanks to a new keyword in PHP 5.3 - "static::" - helps define the difference even clearer.

Check out the rest of the article for a more practical usage too.

Taking full advantage of the upcoming features in the PHP 5.3.x series (and in PHP6 for that matter), Joshua Thompson has come up with a way to accomplish some prototype-based programming in a PHP application:

With the implementation of the get_called_class() function in PHP, prototype based programming in PHP is possible. The new function is in both PHP5.3 and PHP6 snapshots. So, I went back to the drawing board and came up with a fully capable class. The $this keyword is usable, as well as being able to use the self, parent, and static (new with the late static binding patch) keywords.

Prototype-based programming is (basically) a method where classes aren't prebuilt. Instead they are created on the fly based on other objects and interfaces. Joshua's post is a huge code dump of a prototype class and an example of it in use, dynamically creating two methods and making the three objects available.

Mike Lively is happy about one thing - that late static binding (definition) has been committed and will be included with PHP 5.3. Unfortunately, he has a downside too:

The good news is late static binding has been introduced into head and looks like it will be merged into 5.3 before it is released. The horrible news is I really don't think the patch went as far as it needs to.

He talks about the original intention of the functionality (flexible inheritance for static methods/properties/constants) and how it was implemented, but with one small issue - that "static will ALWAYS return the 'resolved' name of the class used to call the current function". He illustrates with a code example showing an extended class returning a static property.

He also mentions two suggestions to help fix this issue:

• setting the behavior of parent:: such that it forwards the calling class through the next function call.
• introducing another scope [...] using a new keyword so parent:: could remain the same

Etienne Kneuss has a new article posted about and introducing a feature that will be implemented in PHP6 - late static bindings.

Late Static Binding (LSB, yes, not LSD) is an OO feature that is meant to be implemented in PHP 6, and maybe even backported to PHP 5. This article will describe what LSB is, what problems it's supposed to solve and how. The patch this article talks about can be found here: late_static_bindings_take6.patch

Etienne explains what they are and includes several code examples to show how they'll work. There's also a mention of "edge cases" where special circumstances might cause the script to fall back on the "magic" functions (__get, __post, etc).

On the LivePipe blog, there's a whishlist that Ryan has posted for some of the things he'd like to see in PHP6.

His list consists of:

• Closures
• { } is the new array()
• Parameter Collection in Functions
• Late Static Binding
• Backwards Compatibility

Each is explained, some with code to illustrate.

From DevShed, there's a more advanced tutorial that might interest PHP developers out there looking for more info on "polymorphism" for their apps.

This article explains what polymorphism is and how it applies to object oriented design in particular. It also explains the pros and cons of polymorphism when working with certain versions of PHP.

They start with a definition on the topic that doesn't seem to help much: "The occurrence of different forms, stages, or types in individual organisms or in organisms of the same species, independent of sexual variations." They do, however, follow that with what it means to programming: "...an interface or base class without regard to an object's concrete class." They also include a simple example (no code, that's later).

With that concept in place, they move to the next step - working with the example to create code that can be used as a reference point. They talk about using a switch to make the script respond differently to different inputs and the lack of "late binding" support in PHP5.