Swift Swift is a new programming language for iOS and OS X 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 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 software development. 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

line: 1 print("Hello, world!") 2 // Prints "Hello, world!" If you have written code in C or Objective-C, this syntax looks familiar to you—in Swift, this line of code is a complete program. You don’t of developing in C and Objective-C. Swift provides its own versions of all fundamental C and Objective-C types, including Int for integers, Double and Float for floating-point values, Bool for Boolean don’t need to change. In addition to familiar types, Swift introduces advanced types not found in Objective-C, such as tuples. Tuples enable you to create and pass around groupings of values. You can use a

6 ⽉月 • Swift 版本：Swift 2 • 依赖很重的 C++ 直播库 • 历史 Objective-C 代码⾏行行数：8 万⾏行行 • 团队 iOS 成员⼈人数：2 ⼈人 • ⼤大家都对使⽤用 Swift 抱有极⾼高的兴趣 决策⽅方案 混编，从此之后不不再写 Objective-C ! 混编进展 • 优势： • ⾯面向协议编程, Lazy Load, type infer • 当前项⽬目代码量量： • Objective-C 25万⾏行行 • Swift 5万⾏行行 • 2018 年年1⽉月开始，新的项⽬目代码⽤用 Objective-C 编写 猿辅导⽼老老师版 的 Swift 迁移之路路 决策回顾 • 背景 • 时间：2016 年年 7 ⽉月 • 全新的项⽬目，历史 Objective-C 代码⾏行行数：0 ⾏行行 • 需要依赖 在编写，但是感觉并不不太特别舒服 ⼩小猿搜题 的 Swift 迁移之路路 决策回顾 • 背景 • 时间：2016 年年 10 ⽉月 • Swift 版本：3.0 版本 • 历史 Objective-C 代码⾏行行数：8 万⾏行行 • 团队 iOS 成员⼈人数：3 ⼈人 • 挑战 • 产品迭代需求⽆无法保证团队有充⾜足时间换到 Swift • 兄弟产品混编 Swift 遇到了了很多问题

the iPhone and Mac today is based on Objective-C code, even for official Apple apps, although Swift usage is gaining traction year after year, and while Objective-C will be used for years to maintain new applications are likely going to be created with Swift. Before Apple introduced Swift, Objective-C was heavily developed to introduce new capabilities and features, but in the recent years this 5 This does not mean Objective-C is dead or not worth learning: Objective-C is still an essential tool for any Apple developer. That said, I am not going to cover Objective-C here, because we're focusing

OBJECTIVE-C TO SWIFT A BRIEF IMMERSION FROM INTRO WHO IS THIS GUY? ▸ ��� (Ruoyu Fu) ▸ A Mobile Developer from ThoughtWorks ▸ Author of SwiftyJSON ▸ A Geek with Drinking Problems WHY SWIFT? DESIGN PATTERNS DESIGN PATTERNS ▸ �������������������������� ���������������������� ▸ �����Objective-C��Swift������������ ��� DESIGN PATTERNS DESIGN PATTERNS ▸ Rule No.1������������� ▸ Rule No