The real problem that autoloaders solve is to load dependencies. [...] The normal logic that's used to justify autoloading over manual dependency loading in production is that it only loads the classes you need. Therefore you save the parsing costs of classes that you don't need. But surely that additional run-time loading has costs. So I decided to setup a test to see how expensive that additional run-time loading costs us, and to prove whether or not autoloading is worth it in production.

He gives an example of the two methods - using the spl_autoload_register method to define a loader and loading them with a defined file path instead. He found the autoloading version slower than the hard-coded (by quite a bit) but how, when the number of files is reduced, the performance gets much closer. He also briefly looks at two other pieces of file-related functionality: file_exists and require_once.

The latest, and last, release of the Zend Framework 1.x series is just around the corner as ZF 1.12.0RC1 was announced this week. As I still have projects running ZF1 I thought about giving the most interesting new feature (for me) a spin - the new autoloaders which are backported from ZF2. I decided using the classmap autoloader as the main autoloader, and the good ol' standard autoloader as the fallback autoloader.

He includes the changes to the Front Controller (index.php) to have it know about these new autoloaders and has a command that will go through your code any pull out any require_once statements out and let the autoloader handle it instead.

Autoloading in PHP is a great time saver. It lets you write concise scripts without the knowledge of the exact directory structure of the libraries you use. But with the arrival of namespaces in PHP 5.3, and the influence of Java over new generation PHP frameworks, autoloading is changing. In the near future, explicit autoloading will be ubiquitous, but with none of the advantages of the old style autoloading.

He talks about "the old days" when things were included manually through file paths, how that graduated to the SPL autoloading and, most recently, up to namespace autoloading. He shares code samples of how the namespace loading works and how you can abuse it to override current classes/functionality with your own. He points out one interesting correlation though - that the "use" keyword seems a lot like the "require_once" of way back when. He shows how the added verbosity of namespace usage can be a hinderance on frameworks, citing microframeworks specifically and showing one implementation that's non-namespaced next to another that is.

• Form validation with PHP
• Converting MySQL to XML
• require_once()-problem
• Search in different tables?
• Getting information out of an XML-file

Here at Smashing Magazine, we want to help out PHP programmers who are just getting started or who want to improve their programming chops. Our goal is to support our community by answering their questions and trying to find solutions to their problems.

You can submit your questions in one of two ways - either via their forum or by sending a tweet (that's on Twitter to him @jasonatennui.

There are numerous discussions in the blogosphere about whether to use echo versus print, if for() is faster than while(), etc. and though the gains are usually very small, I decided to add my thoughts to the debate. I found an article on optimization through coding habits in Ilia Alshanetsky's zend performance slides.

According to his results:

• Calling require_once() 10000 times in a for() loop with an empty file is 4x faster.
• With a simply autoload requiring a class and 10000 loops of new Foo() versus require_once('foo.php'); new Foo() shows that __autoload() is ~3.7 times faster.
• If a class method can be static, declare it static. Speed improvement is by a factor of 4.
• Avoid function calls within for() loop control blocks
• Always, always quote array keys.
• Get rid of 'harmless' error messages - they take time to generate and output.

I am not out to prove Ilia wrong - he knows PHP better than most - and for all I know, they could have optimized those very functions in PHP 5.2. [...] It would appear that there are improvements, albeit small, to achieve from minimal effort. Plus I was surprised by the discrepancies I found compared to Ilia's recommendations.