Learning Swift™ Programming

How Closures Work and Why They’re Awesome

Swift defines a closure syntax that is different from the regular function syntax. This syntax allows you to do a couple things: It allows you to infer the type of the object from the context, and it allows you to return a value without actually writing return. There are several different ways to write closures in Swift, and some of them take very little code. If you are used to replacing or rewriting Objective-C syntax, you may have seen blocks as the last parameter of a function. Swift allows you to write closures outside functions when they are the last parameters. This gives you a nice clean-looking syntax.

Let’s take a look at the sort function in Swift. For this example, you are going to pass two ...