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Book Overview & Buying
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Table Of Contents
Mastering Swift 6 - Seventh Edition
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Closures are self-contained blocks of code that can be passed around and used throughout our application. Like how the Int type holds an integer and the String type holds a string, a closure can be viewed as a type that holds a block of code. We can, therefore, assign closures to variables, pass them as arguments to functions, and return them from functions.
One of the key features of closures is that they can capture and retain references to any variable or constant from the context in which they were created, a process known as closing over variables or constants. Generally, Swift handles the memory management for us, except in cases where a strong reference cycle is created. We will show you how to resolve strong reference cycles in Chapter 15, Memory Management.
Closures in Swift are similar to blocks in Objective-C but are simpler to use and understand. The syntax for defining a closure in Swift is as follows:
{
(<#parameters#>) ->...