On Fri, May 13, 2016 at 12:55 PM, Vladimir.S <[email protected]> wrote:
> > I'm not convinced by this example.
>
> Probably my & Matthew's previous discussion in `[swift-evolution] [RFC]
> #Self` topic will help you. I was trying there to find out (in primitive
> examples) what Matthew is trying to achive with this `->StaticSelf` in
> protocol.
>
> In two words - he wants to achieve requirement 'return Self class or any
> of base classes', as current `->Self` requires 'strictly return Self class'
>
I think I understand what the request is, but I'm not sure if it's a
problem worth solving, and if this would be the right solution.
Going back to the example, let's say you have the requested
protocol Fooable {
func foo() -> StaticSelf
}
class A: Fooable {
func foo() -> A { return A() }
}
class B: A {
}
How would you use foo() in generic code?
func bar<T: Fooable>(_ x: T) -> X {
return x.foo()
}
What does bar() return? What do you put in place of X in its declaration?
You can't use T, you can't use T.StaticSelf. So what's the purpose of
having a protocol if you can't use it in generic code?
Nicola
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