[swift-evolution] [Proposal] Make optional protocol methods first class citizens

[Andrey Tarantsov]

> I do not understand why an optional method should require a default value. That’s not how optional methods work in Objective-C where the caller will ask whether the method is implemented and calls it or does something else. With a default value it would be much more difficult to do something different if the method is not implemented.

Yes, and that's the best part. The way Obj-C optional methods currently work, they are very hard to wrap/proxy/etc. Swift has a lot more expressive power, so I'm sure that you can adjust the return value to express the “I don't care” case without making the absence of the method magical.

A.