<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><blockquote type="cite" style="font-family: Menlo-Regular; font-size: 11px;" class="">On Sep 2, 2016, at 17:50, Douglas Gregor <<a href="mailto:dgregor@apple.com" class="">dgregor@apple.com</a>> wrote:<br class=""><br class="">Hello Swift community,<br class=""><br class="">The review of SE-0140 "Bridge Optional As Its Payload Or NSNull" begins now and runs through September 8, 2016. The proposal is available here:<br class=""><br class=""><a href="https://github.com/apple/swift-evolution/blob/master/proposals/0140-bridge-optional-to-nsnull.md" class="">https://github.com/apple/swift-evolution/blob/master/proposals/0140-bridge-optional-to-nsnull.md</a><br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>• What is your evaluation of the proposal?<br class=""></blockquote><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">It seems like this would improve the utility of bridging collection types (and plist types in general), and I like that it does something more sensible than before with the disparate bridging behavior of Optional<>. But I do have a couple of questions:</span><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">Will specifying a nullable type parameter to collections now become legal in Objective-C? E.g.:</span><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">- (void)takeOptionalCollection:(NSArray<id _Nullable> * _Nullable)collection; // Bridge to [Any?]?</span><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">If not, is there any way to annotate “I want to be able to use (or not use) NSNull in this collection”? If there is, does doing so affect any behaviors on the Objective-C side? If there isn’t, wouldn’t it make more sense to treat passing an optional to Any as requiring forced unwrapping (including the implied runtime crash behavior), as is the case with other uses of optionals now? I can’t think offhand of any use case where I would want an object, even in pure Swift, where I didn’t know whether it was an optional or not, outside of debugging.</span><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">Depending on the answers to these questions, I’m tentatively in favor of this proposal.</span><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><blockquote type="cite" style="font-family: Menlo-Regular; font-size: 11px;" class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>• Is the problem being addressed significant enough to warrant a change to Swift?<br class=""></blockquote><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">Honestly, I don’t feel like it is, but my opinion may not be all that valid, since I’ve spent a great deal more time in pure Swift (and interop with pure C) than in interop with Objective-C.</span><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><blockquote type="cite" style="font-family: Menlo-Regular; font-size: 11px;" class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>• Does this proposal fit well with the feel and direction of Swift?<br class=""></blockquote><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">Yes, *IF* the semantics of Optional remain consistent, which I’m not yet entirely clear on.</span><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><blockquote type="cite" style="font-family: Menlo-Regular; font-size: 11px;" class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>• If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?<br class=""></blockquote><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">I haven’t worked with ObjC bridges in other languages.</span><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><blockquote type="cite" style="font-family: Menlo-Regular; font-size: 11px;" class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>• How much effort did you put into your review? A glance, a quick reading, or an in-depth study?<br class=""></blockquote><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">A quick reading. I was not part of any previous discussion on this topic.</span><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">-- Gwynne Raskind</span><br style="font-family: Menlo-Regular; font-size: 11px;" class=""><span style="font-family: Menlo-Regular; font-size: 11px;" class="">More magic than a mere signature can contain</span></div></body></html>