> On Jan 26, 2017, at 3:10 PM, Dave Abrahams via swift-evolution > <swift-evolution@swift.org> wrote: > > > on Thu Jan 26 2017, David Hart <swift-evolution@swift.org> wrote: > >> Thanks Michael for the manifesto. It definitely made quite a few things >> clearer for me. >> >> Concerning the topic of when ABI stability should happen, I still have >> a strong feelings that Swift 4 might not be the best time for >> it. Concerning Data Layout, Type Metadata, Mangling, the Calling >> Convention and the Runtime, I don’t know enough about them to >> comment. I’m really centring my discussion on the Standard Library. >> >> If we look back at the evolution of the Standard Library for Swift 3, >> they were many changes. And I’m personally very happy with the >> thoughtful design that went into those. But they are still a few >> gotchas, which is to be expected when so many changes are made at >> once. But we only discover them once the thousands of Swift developers >> start using those APIs. >> >> I just worry that all the big changes that will come for Swift 4 won’t >> have time to mature. Furthermore, it seems like several extra compiler >> features which won’t happen in Swift 4 are really necessary to >> simplify the Standard Library surface area. I’m specifically thinking >> of type constraints on Existentials which would allow us to get rid of >> all the Any* structs and replace them with typedefs. But I’m sure >> there are more examples like those which are just waiting for the >> generics to become powerful enough to express APIs more elegantly. >> >> Perhaps someone from the Standard Library team can chime in to give us >> their opinion on this topic. > > I have had exactly the same worry for quite some time. We're still > waiting for many basic components of the generics system, and, if our > experience with protocol extensions is any guide, before we have those > features in hand, it will be impossible to anticipate the design changes > we'd want to make to the standard library... and that cuts against the > grain of *source* (to say nothing of ABI) stability. > > So far I've been unable to form a mental model for what source and/or > ABI stability actually means for our ability to make changes to the > standard library in the future. It's possible that we discover a > workable path forward, but it's equally possible that we find ourselves > painted into a corner.
I hope we can all agree that the last thing we want to do is get painted into a corner. IMO we should be very sure that won’t happen before making a firm commitment to lock down ABI stability. > > -- > -Dave > > _______________________________________________ > swift-evolution mailing list > swift-evolution@swift.org > https://lists.swift.org/mailman/listinfo/swift-evolution _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
