Closure flavor

import Foundation

typealias NormalCallback = (AnyObject?) -> Void
typealias MultipleCallback = (AnyObject?...) -> Void

func on(callback:NormalCallback) {
    callback(1)
}

func onMultiple(callback:MultipleCallback) {
    callback(0, 1, 2)
}

on {println($0)}

onMultiple {data in
    for item in data {
        println(item)
    }
}

// What I wish I could do
//  func on(callback:MultipleCallback) {
//      callback(0, 1, 2)
//  }
//
//  on {data1, data2, data3 in
//    
//  }