<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="">When I call such a mapped Swift API that expects an Int? parameter from Objc with a NSNumber initialized with 3.5, what should happen? <div class=""><br class=""></div><div class="">[NSNumber uint64value: UINT64_MAX] ?<br class=""><div class=""><br class=""></div><div class="">What about the float 1e100? </div><div class=""><br class=""></div><div class="">What about boolean 'true’? </div><div class=""><br class=""></div><div class="">NaN?<div class=""><div class=""><br class=""></div><div class="">-DW</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On May 19, 2017, at 8:54 PM, Jonathan Hull via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">I have to side with Kenny on this one. I would find losing nil vs 0 more surprising than NSInteger vs NSNumber. In fact, I was surprised that this doesn’t already cross to a NSNumber. That would be the behavior I expect.<div class=""><br class=""></div><div class="">Thanks,</div><div class="">Jon<br class=""><div class=""><br class=""></div><div class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On May 16, 2017, at 11:51 AM, Kenny Leung via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">But my argument *is* that optionality is an obvious way to make that decision.</div><div class=""><br class=""></div><div class="">If I was writing in pure Objective-C (outside the context of Swift), sometimes I would have methods that take or return int, and sometimes I would have methods that take or return NSNumber. There is never really a surprise as to why. So why would there be a surprise when bridging from Swift?</div><div class=""><br class=""></div><div class="">-Kenny</div><div class=""><br class=""></div><br class=""><div class=""><blockquote type="cite" class=""><div class="">On May 15, 2017, at 7:24 AM, T.J. Usiyan <<a href="mailto:griotspeak@gmail.com" class="">griotspeak@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">The argument is not about whether or not it should come through as an object. The argument is about the fact that *sometimes* it would come through as an object and other times it would not. Optionality isn't an obvious way to make that decision.<div class=""><br class=""></div><div class="">TJ</div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Mon, May 15, 2017 at 3:03 PM, Charlie Monroe <span dir="ltr" class=""><<a href="mailto:charlie@charliemonroe.net" target="_blank" class="">charlie@charliemonroe.net</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word" class="">This is not much of an argument given that NSString is an object in ObjC (heap-allocated), String in Swift is an struct and also given that most NSNumber's nowadays are not really allocated, but just tagged pointers.<div class=""><br class=""></div><div class="">Given that NSNumber is immutable, you get the value semantics anyway...</div><div class=""><div class="h5"><div class=""><div class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On May 15, 2017, at 1:09 PM, T.J. Usiyan via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>> wrote:</div><br class="m_3753337135911845543Apple-interchange-newline"><div class=""><div dir="ltr" class="">My understanding of the reasoning is that `NSNumber` is an object in Objective-C and not a struct. There is already one level of decision when translating to objc in that regard. Switching between reference semantics/class and value semantics because of optionality is surprising.</div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Mon, May 15, 2017 at 5:52 AM, Kenny Leung via swift-evolution <span dir="ltr" class=""><<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">> On May 12, 2017, at 9:56 AM, John McCall via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>> wrote:<br class="">
<br class="">
> Exporting Int? as an optional NSNumber does not feel obvious and idiomatic when we would export Int as NSInteger. It feels like reaching for an arbitrary solution.<br class="">
<br class="">
</span>I don’t understand this reasoning. I’ve had cause to distinguish 0 from null in both Objective-C and Java, and I would do exactly the same thing.<br class="">
<br class="">
-Kenny<br class="">
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