Many developers still tend to program PHP with their favorite editor and have developed their own preferred methods of debugging their code. But, with millions of developers using PHP, the fact that Integrated Development Environments (IDEs, sometimes abbreviated to Development Environment, or DE) are not as widely used as, say, Visual Studio .NET is for ASP .NET is a bit of a mystery. This may be down to the fact that many people still don't view PHP5 as a full-fledged programming language in its own right (we hope that from what you have seen in this book, you believe otherwise).
At any rate, PHP5 is a full-fledged programming language, and IDEs for it do exist. If you haven't been developing using an IDE that supports PHP5, this appendix is for you. There are a host of useful features packed into the IDEs that might make the investment worthwhile to you. One of their biggest uses, of course, is the sophisticated debugging facilities that most IDEs provide.
Although this appendix won't give you a fully comprehensive rundown of each IDE out there, it will give you an idea of what you can expect from some of the main ones, and an idea of what else is available. For the most part, you should be able to get a deeper understanding of the functionality of each of the DEs from their documentation. We cover the Zend Studio Client first, and in more detail, because this is the largest PHP-centric DE on the market. Following this, alternatives such as Komodo will briefly be explored.