About Swift(关于Swift)
Important(提示)
This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.
本文档包含有关开发中的API或技术的初步信息。此信息可能会更改，根据此文档编写的软件应使用最终操作系统软件进行测试。
Swift is a new programming language for iOS, macOS, watchOS, and tvOS apps that builds on the best of C and Objective-C, without the constraints of C compatibility. Swift adopts safe programming patterns and adds modern features to make programming easier, more flexible, and more fun. Swift’s clean slate, backed by the mature and much-loved Cocoa and Cocoa Touch frameworks, is an opportunity to reimagine how softwaredevelopment works.
Swift 是一种新的编程语言，用于编写 iOS，macOS，watchOS 和 tvOS 的应用程序。Swift 结合了 C 和Objective-C 的优点并且不受 C 兼容性的限制。Swift采用安全的编程模式并添加了很多新特性，这将使编程更简单，更灵活，也更有趣。Swift 是基于成熟而且倍受喜爱的 Cocoa 和 CocoaTouch 框架，它的降临将重新定义软件开发。
Swift has been years in the making. Apple laid the foundation for Swift by advancing our existing compiler, debugger, and framework infrastructure. We simplified memory management with Automatic Reference Counting (ARC). Our framework stack, built on the solid base of Foundation and Cocoa, has been modernized and standardized throughout. Objective-C itself has evolved to support blocks, collection literals,and modules, enabling framework adoption of modern language technologies without disruption. Thanks to this groundwork, we can now introduce a new language for the future of Apple software development.
Swift 的开发从很久之前就开始了。为了给 Swift打好基础，苹果公司改进了编译器，调试器和框架结构。我们使用自动引用计数（Automatic Reference Counting,ARC）来简化内存管理。我们在 Foundation 和 Cocoa 的基础上构建框架栈使其完全现代化和标准化。Objective-C本身支持块、集合语法和模块，所以框架可以轻松支持现代编程语言技术。正是得益于这些基础工作，我们现在才能发布这样一个用于未来苹果软件开发的新语言。
Swift feels familiar to Objective-C developers. It adopts the readability of Objective-C’s named parameters and the power of Objective-C’s dynamic object model. It provides seamless access to existing Cocoa frameworks and mix-and-match interoperability with Objective-C code. Building from this common ground, Swift introduces many new features and unifies the procedural and object-oriented portions of the language.
Objective-C 开发者对 Swift 并不会感到陌生。它采用了 Objective-C 的命名参数以及动态对象模型，可以无缝对接到现有的Cocoa 框架，并且可以兼容 Objective-C 代码。在此基础之上，Swift 还有许多新特性并且支持过程式编程和面向对象编程。
Swift is friendly to new programmers. It is the first industrial-quality systems programming language that is as expressive and enjoyable as a scripting language. It supports playgrounds, an innovative feature that allows programmers to experiment with Swift code and see the results immediately, without the overhead of building and running an app.
Swift 对于初学者来说也很友好。它是第一个既满足工业标准又像脚本语言一样充满表现力和趣味的系统编程语言。它支持代码预览(playgrounds)，这个革命性的特性可以允许程序员在不编译和运行应用程序的前提下运行 Swift 代码并实时查看结果。
Swift combines the best in modern language thinking with wisdom from the wider Apple engineering culture. The compiler is optimized for performance, and the language is optimized for development, without compromising on either. It’s designed to scale from “hello, world” to an entire operating system. All this makes Swift a sound future investment for developers and for Apple.
Swift将现代编程语言的精华和苹果工程师文化的智慧结合了起来。编译器对性能进行了优化，编程语言对开发进行了优化，两者互不干扰，鱼与熊掌兼得。Swift既可以用于开发 “hello, world” 这样的小程序，也可以用于开发一套完整的操作系统。所有的这些特性让 Swift对于开发者和苹果来说都是一项值得的投资。
Swift is a fantastic way to write iOS, macOS, watchOS, and tvOS apps, and will continue to evolve with new features and capabilities. Our goals for Swift are ambitious. We can’t wait to see what you create with it.
Swift 是编写 iOS，macOS，watchOS 和 tvOS 应用的极佳手段，并将伴随着新的特性和功能持续演进。我们对 Swift 充满信心，你还在等什么！
注:
本文中文翻译几乎来自极客学院 ,由于翻译质量非常高,所以直接引入,而且仅仅作为个人学习Swift语法和提高英文水平之用,对此非常感谢,如果想直接查看中文文档,请跳转链接!