Swift is a new object-oriented programming language for iOS and OS X development. Swift is modern, powerful, and easy to use.这是苹果官方网站上Swift的第一句寄语，这句话的意思Swift是一门用于IOS和OS X 的面向对象编程语言。它是现代的，强大的，并且容易使用的语言。
按它这么说，苹果肯定是主推Swift的，并且出来不到一个月，就蹦到语言类排名的16名了，前景一片大好啊。
1.safe
Swift pairs increased type safety with type inference, restricts direct access to pointers, and automatically manages memory—making it easy to create secure, stable software.
2.modern
Swift includes optionals, generics, tuples, and other modern language features. Inspired by and improving upon Objective-C, Swift code feels natural to read and write.
3.powerful
Take advantage of powerful pattern matching in Swift to write simple, expressive code. Format strings naturally with string interpolation. Use frameworks like Foundation and UIKit directly from Swift.
4.interactive
Use playgrounds to experiment with new technologies, analyze problems, and prototype user interfaces.
5.fast
The Swift compiler applies advanced code analysis to tune your code for performance, letting you focus on writing great apps instead of on implementing complex optimizations.
