curried functions in Swift

curried_functions.swift

// Here is a manually curried function.
// maxA takes an int and returns a function, maxB, that takes an int and returns an int.
func maxA(a:Int) -> (Int) -> Int {
    func maxB(b:Int) -> Int {
        return a > b ? a : b
    }
    return maxB
}

// And here is the same function using Swift’s build-in curry fetaure.
// https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Declarations.html#//apple_ref/doc/uid/TP40014097-CH34-XID_615 -> Curried Functions

func maxN(a:Int)(_ b:Int) -> Int {
    return a > b ? a : b
}

let a = 50
let b = 6

maxA(a)(b)
maxN(a)(b)

// While contrived, this demonstrates partially executing max by storing
// the intermediate function and later calling it with the second paramater.
let getGreatestNumber = maxN(a)
getGreatestNumber(5)
getGreatestNumber(60)