Excerpt:
iOS 4 introduces one new feature that will fundamentally change the way you program in general: blocks. Blocks are an extension to the C language and thus fully supported in Objective-C. If you’re coming from a programming language such as Ruby, Python, or Lisp, then you know the power of blocks. Simply put, blocks let you encapsulate chunks of code and pass them around like any other object. It’s a different style of programming that you’ll want to become familiar with to take advantage of new APIs in iOS 4.
Let’s start by taking a look at two examples of where you might use blocks in iOS 4: view animations and enumeration.
