On the PHP::Impact blog today there's a new post showing how to use annotations in your application's code that can be used by the Addendum library.

Annotations provide data about a program that is not part of the program itself. They have no direct effect on the operation of the code they annotate. In PHP, annotations can only be read reflectively at run time.

They allow you to document, with meta-data, information about the classes, methods and variables inside the script. They show three of the annotation types - a marker, a single-value and a multi-value.