Swift Tutorial - Swift Closures

Closures are blocks of code that you can pass to functions as parameters or store as variables or constants.

Closures capture the state of the other variables around them.

var alpha = ["D", "E", "A", "C", "B"]
let alpha_sorted = sorted(alpha, { (s1: String, s2: String) -> Bool in
   return s1 < s2
})

Closures can be stored in variables or constants and used later as parameters.

let closure = { (s1: String, s2: String) -> Bool in
   return s1 < s2
};

let alpha_sorted_2 = sorted(alpha, closure)

The following code shows how to call Closures

let closure = { (s1: String, s2: String) -> Bool in
   return s1 < s2
};

let b = closure("B", "A")