[Spider]Swiftと似た?を使ったチェーンのメモ ref: http://qiita.com/iKichiemon/items/f240a89665f8e4ec4ce3

file0.swift

var name:String?

file1.swift

class Animal {
    func name()->Void{
        println("animal")
    }
}

var animal:Animal?

animal = Animal()

animal?.name()

file2.txt

func Animal() {
    this.name = () -> {
        return "Dog"
    }
}

var animal = new Animal()
animal.name()

var name = animal.name?() // "Dog"
var age = animal.age?()   // undefined