The new hype in programming is all about functional programming
paradigms. Functional languages are used more and more in greater and
better applications. Scala, Haskel, etc. are thriving and other, more
conservative languages like Java started to adopt some of the functional
programming paradigms (see closures in Java7 and lazy eval for lists in
However, what only few people know is that PHP is quite versatile when it comes to functional programming. All the main functional programming concepts can be expressed in PHP. So, if you are new to functional programming, be prepared to have your mind blown, and if you are already familiar with functional programming, be prepared to have great fun with this tutorial.