gistfile1.swift

protocol Fooable {
    var foo: String { get }
}


extension Fooable {
    var foo: String {
        return "foo"
    }
}


extension Int: Fooable {}


extension SequenceType where Self.Generator.Element: Fooable {
    var foo: String {
        return "bar"
    }
}


print(1.foo)
print([1, 2, 3].foo)