swift3.0移除了函数的柯里化

func add(a: Int, b: Int, c: Int) -> Int {
    return a + b + c
}

let d = add(a: 1, b: 2, c: 3)

// swift3.0中支持的柯里化
func addCur(a: Int) -> (_ b: Int) -> (_ c: Int) -> Int {
    return {
        (_ b: Int) -> (_ c: Int) -> Int  in
        return {
            (_ c: Int) -> Int in
            return a + b + c
        }
    }
}