Am 10. Mai 2016 um 20:11 schrieb Matthew Johnson <matt...@anandabits.com>:
Sent from my iPad
On May 10, 2016, at 12:59 PM, Thorsten Seitz <tseit...@icloud.com> wrote:
Am 10.05.2016 um 18:41 schrieb Timothy Wood via swift-evolution
<swift-evolution@swift.org>:
On May 10, 2016, at 9:28 AM, Matthew Johnson <matt...@anandabits.com> wrote:
Yep, understood. It's perfectly clear to me but I understand why Chris is
concerned about it having potential to confuse people. It is a pretty subtle
difference especially since Self and #Self are the same in some contexts. In
any case, I would be content to live with any name that wins out.
Ah, OK -- it sounds like we just differ on what would be least confusing =)
The other proposed name of #StaticSelf, seems like it would be very clear (if a
bit redundant and longer than needed, once you’ve come across it once or
twice). I could certainly live with #StaticSelf.
In that case StaticSelf would be sufficient IMHO. The # should only be needed
to distinguish between Self and #Self.
So:
Self, #Self
Self, StaticSelf
DynamicSelf, StaticSelf
As far as I understand #Self should be the type of the implementor
(ImplementorSelf?) or conforming type (ConformingSelf?).
How would this work with default methods?
protocol A {
func f() -> #Self
init()
}
extension A {
func f() -> #Self { return init() } // what type has #Self here?
}
The conforming type. C in your example. If we have 'class D: C' and it
overrides 'f' the override would have a return type of C, not D. The returned
instance could be of type D since it is a subtype of C. We could also explore
allowing overrides to have a covariant return type, it just wouldn't be visible
when accessed via the protocol through a generic constraint or an existential
(those would only guarantee C, the type that declared the conformance.
Thanks, that makes sense.
So within a default method like in extension A above the (concrete) type of
#Self is still unknown and I only know that it will conform to A. That's fine.
As soon as a non protocol type like a class conforms to the protocol #Self gets
fixed to that type and because we have no multiple inheritance for non
protocols there is no possibility to create conflicts.
-Thorsten_______________________________________________
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