类似 java中的接口，用来实现多种不同方式的多态
import Foundation
protocol baseClass {
}
protocol Action {
var myName:String{
get set
}
var myAge:Int{
get
}
func getMyname()->String
}
protocol child{
func getMyAge()->Int
}
class Inuse:Action,baseClass{
var m_name:String=""
var myName:String{
get{
return "111"
}
set{
m_name=newValue
}
}
var myAge:Int{
get{
return 30
}
}
func getMyname() -> String {
return "my name"
}
}
var sundy:Action=Inuse()
func hello(s:protocol<Action,child>){
}
原文：http://www.cnblogs.com/daochong/p/4836418.html