I thought I'd share a PHP library implementing this idea by Evans and Fowler. Written for PHP5, it's a library for defining custom specifications using composition and inheritance.

He gives the example of "Person" objects with name and age properties. A search might involve looking directly at the properties to location one that's, say, younger than 35 and has a last name of Johnson. His specification class replaces this and makes it more reusable by applying things like GreaterOrEqualSpecifications and EqualSpecifications to standardize the evaluation. Then its just a quick call to the isSatisfiedBy method to check for correctness.

Today Microsoft announced a significant initiative which aims to provide the developer community with access to a large number of Microsoft protocols and file formats. [...] With Microsoft opening up their specifications under the OSP, open-source communities like Zend Framework are now able to build such solutions without fear of litigation. There are many other areas where it will benefit open-source projects including Samba (SMB), FreeTDS (SQL Server), Mono (.NET), and others...

He shares his thoughts on the winners (Microsoft themselves, Open Source community) and losers (Microsoft's competitors, Linux) on the deal and the beneficial impact he thinks it will all have on the PHP.

Because I love all things OpenID related and am an OpenID "pusher" in Europe (blame the OpenID Europe Foundation membership on Snorri Giorgetti), I'll be proposing a PHP5 implementation of OAuth to the Zend Framework (assuming no other OAuth proposal) and PEAR (PEAR because that's now the home of my OpenID For PHP library under proposal).

You can get more information about OAuth from the project's website.