<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=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jan 16, 2017, at 10:28 AM, Karl Wagner <<a href="mailto:razielim@gmail.com" class="">razielim@gmail.com</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 dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On 13 Jan 2017, at 23:02, Joe Groff 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=""><br class=""><blockquote type="cite" class="">On Jan 13, 2017, at 1:10 PM, Anton Zhilin via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class=""><br class="">That seems pretty close to Rust’s derive. Why not invent a similar syntax in Swift? Otherwise it will make us look through all the sources to make sure deriving is used.<br class=""><br class="">enum Option: @derive Equatable {<br class=""> ...<br class="">}<br class=""></blockquote><br class="">My feeling on this is that it feels strange to treat compiler-provided default implementations as different from library-provided default implementations. If the library provides a protocol extension with an appropriate default implementation for your type, you get it without any work on your part. While the Equatable/Hashable/Comparable conformance would most practically compiler generated today, you could imagine a far future version of Swift having sufficiently powerful generic type traits to do this in the library.<br class=""><br class="">-Joe<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 class="">It would be helpful for synthesised RawRep conformance. The inheritance-like syntax we have now is awful - it makes people think that RawRepresentable is some kind of magic protocol that will allow special compiler jango to happen.</div><div class=""><br class=""></div><div class="">You could see why they think that. This looks very much like the enum is going to *be* an Int32:</div><div class=""><br class=""></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><div class=""><font face="Courier" class="">enum Something: Int32 {</font></div><div class=""><font face="Courier" class=""> case oneThing = 36</font></div><div class=""><font face="Courier" class=""> case anotherThing = 42</font></div><div class=""><font face="Courier" class="">}</font></div><div class=""><font face="Courier" class=""><br class=""></font></div></blockquote>This is also one of the icky parts to allowing tuples of integer/string literals (something people ask for quite a lot). It would look like you’re deriving your enum from a non-nominal type:<div class=""><br class=""></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><div class=""><div class=""><font face="Courier" class="">enum Something: (Int32, Int32) {</font></div></div><div class=""><div class=""><font face="Courier" class=""> case oneThing = (3, 12)</font></div></div><div class=""><div class=""><font face="Courier" class=""> case anotherThing = (5, 9)</font></div></div><div class=""><div class=""><font face="Courier" class="">}</font></div></div><div class=""><font face="Courier" class=""><br class=""></font></div></blockquote>Getting back to the topic: we should do this. We do it for plain enums. We do it for tuples of Equatables.</div></div></div></blockquote><br class=""></div><div>Tuples of Equatables are not themselves Equatable just yet, though that would be a reasonable thing to add. They just have a bunch of `==` overloads.</div><div><br class=""></div><div>-Joe</div></body></html>