Yesterday Apple released the new beta4 with new changes in the Swift language. The big thing is the new acces control with three acces levels (private, internal and public). This will allow us to make better APIs for our code.

You should read the rest of the release notes for beta4 or this simpler post with the diff for the Swift language.

Swift is very young, still in beta and people keep publishing facts on how we should used it. I recommend you to wait until the language becomes more mature for that.