Functional Programming: A PragPub Anthology

Anatomy of Swift Functions

Let’s start with a simple “Hello, World!” Swift function:

func mySimpleFunction() {
    println("hello, world!")
}

If you’ve ever programmed in any other language aside from Objective-C, the preceding function should look very familiar:

• The func keyword denotes that this is a function.
• The name of this function is mySimpleFunction.
• There are no parameters passed in—hence, the empty ( ).
• There is no return value.
• The function execution happens between the { }.

Now on to a slightly more complex function:

func myFunctionName(param1: String, param2: Int) -> String {
    return "hello, world!"
}

This function takes in one parameter named param1 of type String and one parameter named param2 of type Int and returns a String ...