An intro to currying functions in Swift

currying.swift

// Currying
func say (hello: String) (to: String) -> String {
    return "\(hello), \(to)."
}

// English
let helloWorld = say("Hello")(to: "world")                  //-- "Hello, world."

// Spanish
let hola      = say("Hola")                                 //-- function
let holaWorld = hola(to: "world")                           //-- "Hola, world."
let holaAmigo = hola(to: "amigo")                           //-- "Hola, amigo."

// Other way
func say (#nameFirst: Bool) -> String -> String -> String {
    func sayTo (to: String) (hello: String) -> String {
        return say(hello)(to: to)
    }
    return nameFirst ? sayTo : say
}

let konichiwaRob   = say(nameFirst: false)("Konichi wa")("Robato desu")//-- "Konichia wa, Robarto desu."
let bulaBulaSmiley = say(nameFirst: true)("Smiley Rob")("Bula Bula")   //-- "Bula Bula, Smiley Rob."