They're mentioned in passing in the Zend_View documentation, but not reviewed in detail anywhere in the Reference Guide as of version 1.5.2. I was curious enough about how to implement markup minification that I decided to trace through the Zend_View source code in attempt to discern how output filters actually worked. As it turns out, it's actually pretty simple.

He explains a simple example of how they work, using a Zend_View object to build the filters on (addFilterPath/setFilterPath), and how he created his own output filter - the Minify filter. A minifier removes the comments and whitespace in the output to help reduce its size.

We decided that this one package should be split into subpackages: one subpackage per region/country. Some advantages of this approach are that each driver / filter / subpackage gets it's own stability and version number - we wouldn't have to keep increasing the version number of Date_Holidays each time a new driver is added or when an existing driver gets a significant number of fixes.

To replace your current version of the package (with all of the regions built in) with a new version that still contains all versions, uninstall the Date_Holidays and grab the "Date_Holidays#all" package. Otherwise, you can check out the PEAR page for the main package and see the subpackage list if you only need one for your area.

HTMLPurifer is possibly the most understated underpublicised quality library in PHP today. I consider it a fundamental standard library that is automatically included in every PHP web application I start these days.

This latest release candidate (their first!) includes updates on two major features - the use of autoloading and a change to the way you use the filters. Check out a demo of it in action or just download this latest release and try it out for yourself.

I've uploaded the 0.3 release of Inspekt, the input filtering and validation library for PHP4 and 5. With this release, Inspekt completes the goals of the original specification for the OWASP SpoC007 project. I believe it is ready for "real-world" use.

Along with the new code being released there's also more documentation, API docs, a PEAR channel and a mailing list.