<div dir="ltr">Personally I think we should just remove these optional-taking variants of the comparison operators. Does anyone agree/disagree?<div><br></div><div>It does make sense to keep ==(T?, T?) and !=(T?, T?), and if coercion were removed, we might want to add (T, T?) and (T?, T) versions. Are there any other operators that would be affected by your proposal? If not, removing the optional </<=/>/>= would obviate the need to remove coercion.</div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div>Jacob<br></div></div></div></div>
<br><div class="gmail_quote">On Mon, Jul 11, 2016 at 4:45 PM, Mark Lacey <span dir="ltr"><<a href="mailto:mark.lacey@apple.com" target="_blank">mark.lacey@apple.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><br><div><span class=""><blockquote type="cite"><div>On Jul 11, 2016, at 4:32 PM, Jacob Bandes-Storch <<a href="mailto:jtbandes@gmail.com" target="_blank">jtbandes@gmail.com</a>> wrote:</div><br><div><div dir="ltr">Great, thanks Mark! I look forward to it.</div></div></blockquote><div><br></div></span>To be clear, I’m specifically looking at making the change to remove the coercion from T to T? for operator arguments.</div><div><br></div><div>I agree there might be other things worth looking at regarding operators that take optionals, but I’m not currently looking at those issues.</div><span class="HOEnZb"><font color="#888888"><div><br></div><div>Mark</div></font></span><span class=""><div><br><blockquote type="cite"><div><div dir="ltr"><div class="gmail_extra">
<br><div class="gmail_quote">On Mon, Jul 11, 2016 at 4:31 PM, Mark Lacey <span dir="ltr"><<a href="mailto:mark.lacey@apple.com" target="_blank">mark.lacey@apple.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">Hi Jacob,<div><br><div><span><blockquote type="cite"><div>On Jul 11, 2016, at 4:23 PM, Jacob Bandes-Storch via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>> wrote:</div><br><div><div dir="ltr">Bump for Swift 3.<div class="gmail_extra">
<br><div class="gmail_quote">On Thu, Jul 7, 2016 at 2:37 PM, Jacob Bandes-Storch <span dir="ltr"><<a href="mailto:jtbandes@gmail.com" target="_blank">jtbandes@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>These operators cause some potential for confusion:</div><div><br></div><div><div> public func <<T : Comparable>(lhs: T?, rhs: T?) -> Bool</div><div> public func ><T : Comparable>(lhs: T?, rhs: T?) -> Bool<br></div><div> public func <=<T : Comparable>(lhs: T?, rhs: T?) -> Bool<br></div><div> public func >=<T : Comparable>(lhs: T?, rhs: T?) -> Bool</div><div><br></div><div>1. The meaning of T? < T? is not immediately obvious (Why is nil < .some(x) for any x? Personally, my intuition says that Optional should only provide a partial order, with .none not being ordered w.r.t. .some(x).)</div><div><br></div><div>2. Even if the meaning is understood, it can be surprising when the (T?, T?) -> Bool version is used instead of (T, T) -> Bool.</div><div><br></div><div>Prior discussion:</div><div>- <a href="http://thread.gmane.org/gmane.comp.lang.swift.devel/2089" target="_blank">http://thread.gmane.org/gmane.comp.lang.swift.devel/2089</a><br></div><div>- <a href="http://thread.gmane.org/gmane.comp.lang.swift.evolution/10095" target="_blank">http://thread.gmane.org/gmane.comp.lang.swift.evolution/10095</a></div></div><div><span style="font-size:12.8px">- <a>rdar://</a></span><span style="font-size:12.8px">16966712&</span><span style="font-size:12.8px">22833869</span></div><div><span style="font-size:12.8px">- Replies to <a href="https://twitter.com/jtbandes/status/646914031433871364" target="_blank">https://twitter.com/jtbandes/status/646914031433871364</a></span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">In the swift-dev thread from May, Chris said:</span></div><div><span style="font-size:12.8px"><br></span></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span style="font-size:12.8px">One of the ideas that Joe Pamer has been discussing is whether the implicit promotion from T to T? should be disabled when in an operator context. Doing so would fix problems like this, but making the code invalid.</span></blockquote><div style="font-size:12.8px"><br></div></blockquote><div><br></div><div>A change like this would be source-breaking, so if the core team has recommendations for how to handle these issues, now is probably the time to get it done.</div></div></blockquote></div></div></div></div></blockquote><div><br></div></span>I overlooked your previous message on this.</div><div><br></div><div>I’m actually writing up a proposal for this now, and have an implementation that I’ve done a bit of testing with.</div><div><br></div><div>I’m hoping to get the proposal out in the next couple days.</div><span><font color="#888888"><div><br></div><div>Mark</div><div><br></div></font></span></div></div></blockquote></div><br></div></div>
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