Book Image

Swift High Performance

By : Kostiantyn Koval
Book Image

Swift High Performance

By: Kostiantyn Koval

Overview of this book

Swift is one of the most popular and powerful programming languages for building iOS and Mac OS applications, and continues to evolve with new features and capabilities. Swift is considered a replacement to Objective-C and has performance advantages over Objective-C and Python. Swift adopts safe programming patterns and adds modern features to make programming easier, more flexible, and more fun. Develop Swift and discover best practices that allow you to build solid applications and optimize their performance. First, a few of performance characteristics of Swift will be explained. You will implement new tools available in Swift, including Playgrounds and REPL. These will improve your code efficiency, enable you to analyse Swift code, and enhance performance. Next, the importance of building solid applications using multithreading concurrency and multi-core device architecture is covered, before moving on to best practices and techniques that you should utilize when building high performance applications, such as concurrency and lazy-loading. Finally, you will explore the underlying structure of Swift further, and learn how to disassemble and compile Swift code.
Table of Contents (15 chapters)
Swift High Performance
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Safety


Swift is designed for safety. It eliminates many issues of compile time. Here is a list of things that Swift handles for you:

  • Type safety: Swift is very strongly typed language. If a function has the Int parameter, you must pass Int as an argument when you call it. This rule also applies to operators. Swift doesn't allow use of the wrong type:

    func increase(x: Int) -> Int {
      return x + 1
    }
    
    let x = 10
    let percent = 0.3
    let name = "Sara"
    
    x + name //Error, can't apply + operator for Int and String
    x * percent //Error, can't apply * to Int and Double
    Double(x) * percent // 3
    
    increase(x) // 11
    increase(percent) // Wrong type
    increase(name) // Wrong type
  • Variables must always be initialized before use: Accessing non-initialized memory is a dangerous operation. Swift handles this problem in a very nice and safe way. It doesn't compile when you try to do that:

    var y: Int
    //y + 10 //Error, variable 'y' used before being initialized
    y = 1
    y + 10

    Constant values can't be changed after they...