Currying in Swift

gistfile1.swift

func curry<A,B>(fun: (A)->B, arg: A) -> (() -> B) {
    return { return fun(arg) }
}
func curry<A,B,C>(fun: (A,B)->C, arg: A) -> ((B) -> C) {
    return { return fun(arg, $0) }
}

func square(i: Int) -> Int { return i * i }
let sq2 = curry(square, 2)
let res = sq2()
// => 4

func log(what: String) {
    println(what)
}
let lg = curry(log, "foo")
lg()
// logs "foo"

func foo(a: Int, b:Int) -> Int {
    return a * b
}

let fo = curry(foo, 2)
fo(3)
// => 6

func kw(some a:Int, other b:Int) -> Int {
    return a - b
}
kw(some: 2, other: 1)
let kwa = curry(kw, 10)
kwa(50)
// => -40

class Adder {
    var base = 5
    func add(a: Int, b: Int) -> Int {
        return base + a + b
    }
}

let adder = Adder()
adder.add(2, b: 1)
let bla = curry(adder.add, 2)
bla(1) // => 8
adder.base = 0
bla(1) // => 3