> On Dec 18, 2015, at 4:19 PM, Kevin Ballard <ke...@sb.org> wrote: > On Fri, Dec 18, 2015, at 04:11 PM, John McCall wrote: >> I think any storage-in-extensions proposal ought to be a special feature of >> classes; I would not support the ability to add stored properties to structs >> in extensions, even from within the module. > > Oh that's an interesting idea. My immediate reaction to "I don't want > unpredictable sizes" was upon reflection something that only applies to > structs. Classes are reference types already, so adding storage to them > doesn't really have much consequence (structs get copied around so their size > is important). Not only that, but we can already use associated objects with > classes, so adding proper stored properties to them doesn't actually change > the semantics of extensions, it just means avoiding the overhead of > associated objects (and of value wrappers for associated objects) when the > extension is part of the same module.
Right. And I think we’d also want to support some way to explicitly request the out-of-line representation even within the module. John. _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
