Introduction to automated, static code analysis in PHP

In my daily work one of my jobs is to assure code quality of our web applications written in PHP. Beside the usual checks like manual code review, training (e.g. using XP programming sessions) and automated unit tests using PHPUnit, there are some metrics that can be measured automatically making my work easier and helping to reduce error rates in the review process. In the following article I want to introduce the most common methods and tools addressing static code analysis in PHP.