协议的检查与转换

protocol Slogan {
    var desc:String {get}
}

protocol Coder:Slogan {
    var name:String {get}
}


struct JavaCoder:Coder {
    var name:String
    var desc:String {
        return "会Java"
    }
}

struct JsCoder:Coder {
    var name:String
    var desc:String {
        return "会Js"
    }
}


struct NewBie {
    var name:String
    var desc:String {
        return "新手"
    }
}


let java = JavaCoder(name:"张三")
let js = JsCoder(name:"李四")
let newBie = NewBie(name:"王五")

let array = [java,js,newBie] as [Any]

for elements in array {
    
    if let element = elements as? Coder {
        print(element.name,element.desc)
    }
    
    if let element = elements as? NewBie {
        print("\(element.name)是一个新手")
    }
}

for element in array {
    if element is Coder {
        print("程序员")
    }
    
    if element is NewBie {
        print("新手")
    }
}