On PHP 5.3, Lambda Functions, and Closures – Fabien Potencier

PHP 5.3 will have a lot of exciting new features. One of the most important one for me is the introduction of lambda functions and closures support. I won't talk too much about what lambda functions or closures are, as you can find many good blog posts describing them in great details. To sum up, a lambda function is an anonymous PHP function that can be stored in a variable and passed as an argument to other functions or methods. A closure is a lambda function that is aware of its surrounding context.