We started the study of PHP magic methods by learning about __get() magic method. [...] PHP is loosely typed language and same variable can be used or referred as string, number or object. The __toString() method is called when the code attempts to treat an object like a string. This function does not accept any arguments and should return a string.

Some quick code is included showing how it works - returning a combined string made from two private class properties when the object ($obj) is echoed out. They also show multiple ways of using the method in both pre- and post-PHP 5.2.

The usage of getter and setter methods instead of public attributes became very popular in the PHP community, and it's going to become the standard coding convention of so many PHP libraries and frameworks. On the other hand many developers - including me too - strongly unrecommend such convention, because of its performance overhead. I wanted to make some performance comparison for years, and today I had time to do that. In this post I would like to show what I found.

He starts with a question every developer asks as their working in their application - why and when should they use getters and setters for their classes. He talks about using them as primary functionality or as fallbacks only when needed. He includes the simple benchmarking script he used to compare accessing/setting public attributes directly and using a getter/setter to do the same. The results aren't very surprising if you think about the "magic" that has to happen for getters and setters to work. See the rest of the post for those numbers.

In my previous post ( PHP Magic Functions ), I discussed about __construct, __destruct, __call and __callStatic. Lets explore a few more magic functions...

In this latest part of the series they look at three functions:

• __set/__get
• __invoke

There are some reserved function names in PHP class starting with __ ( double underscore ). These are __construct, __destruct, __isset, __unset, __call, __callStatic, __sleep, __wakeup, __get, __set, __toString, __set_state, __invoke and __clone. You cannot use these functions to serve your logical purpose but these are meant to be used for providing magic functionality.

They go through some of the above methods and talk about what role they can play in your code and, for some, a brief bit of code to explain how it works. This first part covers __construct/__destruct and __call/__callStatic.

I've been working on a proposal for including service locators and dependency injection containers in Zend Framework 2.0, and one issue I've had is trying to explain the basic concept to developers unfamiliar with the concepts -- or with pre-conceptions that diverge from the use cases I'm proposing.

Using his wife as a sample sounding board, he came up with a restaurant-based analogy to help explain the concept - asking for certain pre-planned things but wanting customizations. He reminds developers that there's not much "magic" to DI. Things are all well defined from the outset and you only have to use it when you want.

PHP version 5.3 introduced a new magic method designed __invoke, this method is called when a script tries to call an object as a function. [...] As php cannot accommodate pseudo-first-class functions, the __invoke method can be used to suppress this language limitation. On other hand you can use this for simpler things as pass a function around.

He includes a simple code example that shows a basic class being called via a variable name - $c('ford') - and the result of its __invoke method being called. He notes that the method, in his opinion, could make for less clean code.

PHP provides a number of 'magic' methods that allow you to do some pretty neat tricks in object oriented programming. These methods, identified by a two underscore prefix (__), function as interceptors that are automatically called when certain conditions are met. Magic methods provide some extremely useful functionality, and this tutorial will demonstrate each method's use.

They define a sample class so you can see them in context - a Device and a Battery. They cover constructors/destructors, get/set, isset/unset, toString, clone and more (including the callStatic that's only in the recent PHP 5.3 versions of the language).

The "magic" methods are ones with special names, starting with two underscores, which denote methods which will be triggered in response to particular PHP events. That might sound slightly automagical but actually it's pretty straightforward, we already saw an example of this in the last post, where we used a constructor - so we'll use this as our first example.

She talks about nine of these magic functions including:

• __get/__set for variable handling
• __sleep/__wakeup for serializing data
• __call/__callStatic for methods in a class
• __construct/__destruct for making and destroying classes

There are a few [other methods] that can be really useful for performing relatively complex tasks with a minimal amount of code. That's exactly the case with the "__destruct()" method, which will be called automatically by the PHP engine before destroying an instance of a particular class at the end of a script.

They update their example class with a new __destruct method that takes the user information inserted previously, serializes it and drops it into the current session.

PHP 5 offers yet another magic method that can be extremely useful for loading classes automatically, without having to use explicitly any "include()/include_once()" or "require()/require_once()" function. As the article's title suggests, I'm talking specifically about the "__autoload()" function, which deserves a deeper analysis.

Their example shows how to define the __authoload method for your application to load in libraries as they're needed, without having to specifically define them.