When you are working with Apples Foundation framework you have probably stumbled across NS_ENUM and NS_OPTIONS (since iOS 6 and OS X Mountain Lion). Both NS_ENUM and NS_OPTIONS are marcros that use the C enum under the hood, and if you have used C enums before you will probably understand these macros, kind of, right away.
Last year at WWDC, Apple released their new programming language, Swift. The development of the language has progressed real quick since the release, and by now Swift 2 is in Beta and available to developers through Apples Developer Portal. The release has been a great success and Swift has become one of the most beloved programming languages out there! As a twist, the language is also expected to be released as open-source this fall.