Can I simulate traits/mixins in Swift?

Question

Does Swift have a way of mixing in traits, a la Scala? The section of the Swift book on using extensions to add protocols to existing classes comes tantalizingly close. However,

Answer 1

Similar to Bryan Chen's answer:

import Foundation

protocol Named {
    var name : String { get }
}

protocol NamedExtension : Named { // NB extends Named
    var lowercaseName : String { get }
    var uppercaseName : String { get }
}

struct NamedExtensionDefault { // Put defaults inside a struct to keep name spaces seperate
    static func lowercaseName(named : NamedExtension) -> String {
        return (named.name as NSString).lowercaseString
    }
    static func uppercaseName(named : NamedExtension) -> String {
        return (named.name as NSString).uppercaseString
    }
}

extension Int : NamedExtension {
    var name : String {
    return "Int"
    }
    // Use default implementation
    var lowercaseName : String {
    return NamedExtensionDefault.lowercaseName(self)
    }
    var uppercaseName : String {
    return NamedExtensionDefault.uppercaseName(self)
    }
}

1.name // result Int
1.uppercaseName // result "INT"
1.lowercaseName // result "int"

The main difference from Bryan's answer is that I didn't use generics because I made NamedExtension extends Named, so that the default implementations can access name.