<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="">Ditto. It's way too early to be doing this. This is something to be done when most major APIs are converted to Swift. This would make Swift hard to use for any interaction with JSON if you use NSJSONSerialization and pretty much with any NSDictionary...<div class=""><br class=""><div class="">
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<br class=""><div><blockquote type="cite" class=""><div class="">On May 25, 2016, at 6:49 AM, Douglas Gregor 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=""><div style="font-family: Helvetica; font-size: 10px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><blockquote type="cite" class=""><div class=""><br class="Apple-interchange-newline">On May 23, 2016, at 5:26 PM, Jordan Rose 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=""><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="">I am way late, but I share Brent’s concerns. I don’t think this addresses the very common case of “getting a String out of a heterogeneous dictionary”.</div><div class=""><br class=""></div><blockquote class="" style="margin: 0px 0px 0px 40px; border: none; padding: 0px;">let name = plist[“name”] as! String</blockquote><div class=""><br class=""></div>becomes one of these:<div class=""><br class=""><blockquote class="" style="margin: 0px 0px 0px 40px; border: none; padding: 0px;">let name = plist[“name”] as! NSString as String</blockquote><blockquote class="" style="margin: 0px 0px 0px 40px; border: none; padding: 0px;">let name = String(plist[“name”] as! NSString)</blockquote><blockquote class="" style="margin: 0px 0px 0px 40px; border: none; padding: 0px;">let name = String(forceBridging: plist[“name”]) // not in the proposal</blockquote><div class=""><br class=""></div>none of which I’m particularly happy with. <br class=""></div></div></div></blockquote><div class=""><br class=""></div><div class="">I am also way, way late, here, but this ties into a philosophical concern I have. The bridging that we have in place was designed to put Swift’s value types front-and-center in the Swift experience, even when interoperating with Objective-C APIs using reference-semantic types. It was a specific goal that one should not have to juggle between Swift.Array and NSArray—NSArray is bridged away in imported APIs, Swift arrays implicitly convert to AnyObject when working an AnyObject-based API, dynamic bridging conversions would pass through NSArray to get to Swift arrays, etc. So while one can certainly reach for NS(Mutable)Array in Swift, one should not *have* to do so in Swift.</div><div class=""><br class=""></div><div class="">This proposal and SE-0072 are chipping away at that bridging story, making the explicit use of NSArray/NSString/etc. required for interoperability with Objective-C APIs. While it does make the language more explicit and predictable (and dynamic casting more efficient!), it makes the use of these bridged reference-semantic more prevalent, which may lead to more overall confusion about which set of types to use. There might even be a portability argument: the current scheme lets you gloss over Any vs. AnyObject (which is a current difference we see in ObjC Foundation vs. corelibs Foundation).</div><div class=""><br class=""></div><span class="Apple-tab-span" style="white-space: pre;"> </span>- Doug</div><div style="font-family: Helvetica; font-size: 10px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""><blockquote type="cite" class=""><div class=""><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class=""><div class=""><br class=""></div><div class="">Jordan</div><div class=""><br class=""></div><br class=""><div class=""><blockquote type="cite" class=""><div class="">On May 19, 2016, at 02:31, Brent Royal-Gordon 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=""><div class=""><blockquote type="cite" class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>* What is your evaluation of the proposal?<br class=""></blockquote><br class="">The review is technically over, but I don't believe a decision has been announced yet, so...<br class=""><br class="">I am generally in favor, but I have a serious concern about the readability of certain conversions with this change. To wit, conversions like these:<br class=""><br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>myArray as! [NSView]<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>myDictionary as! [String: NSView]<br class=""><br class="">Are about to become something more like these:<br class=""><br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>[NSView](forcedLazyBridging: myArray)<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>[String: NSView](forcedLazyBridging: myDictionary)<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span><br class="">Or these:<br class=""><br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>Array<NSView>(forcedLazyBridging: myArray)<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>Dictionary<String, NSView>(forcedLazyBridging: myDictionary)<br class=""><br class="">Either option is a significant regression in code readability compared to the status quo.<br class=""><br class="">It's enough to make me wonder if we shouldn't have special-cased conversion methods for NSArray, NSDictionary, and NSSet:<br class=""><br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>myArray.of(NSView)<span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span>// returns [NSView]<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>myDictionary.of(NSView, for: String)<span class="Apple-converted-space"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span>// returns [String: NSView]<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>mySet.of(NSView)<span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span>// returns Set<NSView><br class=""><br class="">On the other hand, if you *don't* have to specify an element type, these aren't so bad:<br class=""><br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>Array(forcedLazyBridging: myArray)<br class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>Dictionary(forcedLazyBridging: myDictionary)<br class=""><br class="">And it gets even better if you use something a little saner than `forcedLazyBridging` for the label.<br class=""><br class=""><blockquote type="cite" 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 class="">Yes. Conversions are a mess, and it'll be nice to clean them up.<br class=""><br class=""><blockquote type="cite" 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 class="">Yes.<br class=""><br class=""><blockquote type="cite" 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 class="">Most languages I've used have had much simpler cast systems with nothing particularly close to Swift's bridging casts.<br class=""><br class=""><blockquote type="cite" 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 class="">Quick reading.<br class=""><br class="">--<span class="Apple-converted-space"> </span><br class="">Brent Royal-Gordon<br class="">Architechies<br class=""><br class="">_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class=""><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a><br class=""></div></div></blockquote></div><br class=""></div></div>_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class=""><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a><br class=""></div></blockquote></div><br class="" style="font-family: Helvetica; font-size: 10px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><span style="font-family: Helvetica; font-size: 10px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">_______________________________________________</span><br style="font-family: Helvetica; font-size: 10px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 10px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">swift-evolution mailing list</span><br style="font-family: Helvetica; font-size: 10px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><a href="mailto:swift-evolution@swift.org" style="font-family: Helvetica; font-size: 10px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">swift-evolution@swift.org</a><br style="font-family: Helvetica; font-size: 10px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" style="font-family: Helvetica; font-size: 10px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a></div></blockquote></div><br class=""></div></body></html>