<div dir="ltr">My apologies for the double post but 2.2 (no need for backticks around 'else' as a parameter name) allows a slightly different approach right now (I am not exactly suggesting that this solves the problem completely, just seeing what it looks like.)<div><br></div><div> func unwrap<Wrapped>(wrapped: Wrapped?, _ unwrapHandler: Wrapped -> Void, else failureHandler: Void -> Void) {</div><div><span class="" style="white-space:pre"> </span> switch wrapped {</div><div><span class="" style="white-space:pre"> </span> case let .Some(value):</div><div><span class="" style="white-space:pre"> </span> unwrapHandler(value)</div><div><span class="" style="white-space:pre"> </span> case .None:</div><div><span class="" style="white-space:pre"> </span> failureHandler()</div><div><span class="" style="white-space:pre"> </span> }</div><div><span class="" style="white-space:pre"> </span>}</div><div><br></div><div><span class="" style="white-space:pre"> </span>// allows</div><div><br></div><div><span class="" style="white-space:pre"> </span>let theBox:Int? = 4</div><div><br></div><div><span class="" style="white-space:pre"> </span>unwrap(theBox, { print("the value is \($0)") }</div><div><span class="" style="white-space:pre"> </span> , else: {</div><div><span class="" style="white-space:pre"> </span> print ("Nothing in the box!")</div><div><span class="" style="white-space:pre"> </span>})</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Feb 1, 2016 at 3:14 PM, T.J. Usiyan <span dir="ltr"><<a href="mailto:griotspeak@gmail.com" target="_blank">griotspeak@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">Ok, would that mean that we could use closure syntax to …associate the value with a name?<div> </div><div><div style="font-size:13px"><font face="Menlo"> if bind foo.somethingReturningAnOptional { foo in</font></div><div style="font-size:13px"><font face="Menlo"> // ???</font></div><div style="font-size:13px"><font face="Menlo"> }</font></div></div><div style="font-size:13px"><font face="Menlo"><br></font></div><div><font face="Menlo">I think that the question brings me back to my initial thought when reading this that it is dangerously "close but not quite the same as" the 'other' meaning of `bind`. I don't thank that the closeness should shut down discussion of this but I would like to float the name `unwrap` instead. This makes a near-implementation that is currently possible make more sense.</font></div><div><font face="Menlo"><br></font></div><div><font face="Menlo">func unwrap<Wrapped>(wrapped: Wrapped?, handler: Wrapped -> Void) -> Bool</font><span style="font-family:Menlo"> </span></div><div><font face="Menlo"><br></font></div><div><font face="Menlo"><br></font></div><div><font face="Menlo">The `Bool` represents whether or not the unwrap was successful and the `else` flows from that thought without issue. (`bind` works in this regard as well but becomes, in my opinion, it becomes even more confusing to have a bind with the suggested signature.)</font></div><span class="HOEnZb"><font color="#888888"><div><font face="Menlo"><br></font></div><div><font face="Menlo">TJ</font></div><div><font face="Menlo"><br></font></div></font></span></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Feb 1, 2016 at 2:27 PM, Erica Sadun <span dir="ltr"><<a href="mailto:erica@ericasadun.com" target="_blank">erica@ericasadun.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"><div>It would have to be something along the lines of $0 wouldn't it? If there was no clear single symbol to shadow?</div><div><br></div><div>That's a very good point, and thank you for bringing it up.</div><span><font color="#888888"><div><br></div><div>-- Erica</div></font></span><div><div><br><div><blockquote type="cite"><div>On Feb 1, 2016, at 12:22 PM, T.J. Usiyan <<a href="mailto:griotspeak@gmail.com" target="_blank">griotspeak@gmail.com</a>> wrote:</div><br><div><div dir="ltr"><div>This is interesting. What name is created by </div><div><br></div><div><div style="font-size:13px"><font face="Menlo"> if bind foo.somethingReturningAnOptional {</font></div><div style="font-size:13px"><font face="Menlo"> // ???</font></div><div style="font-size:13px"><font face="Menlo"> }</font></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Feb 1, 2016 at 2:18 PM, Erica Sadun via swift-evolution <span dir="ltr"><<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</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">Joe says "<span style="font-family:Palatino-Roman">If you all are serious about this, I think you should start a new thread about it." </span><div>I think it's worth a serious discussion just so it can be evaluated and either adopted or discarded</div><div>and dropped forever. Here goes.</div><div><br></div><div>INTRO</div><div><br><div>The <font face="Menlo">if let x = x {...}</font> and <font face="Menlo">guard let x = x else {...}</font> constructs do something with <font face="Menlo">let</font> (and <font face="Menlo">var</font>) that's </div><div>fundamentally different from <font face="Menlo">let</font> (and <font face="Menlo">var</font>) elsewhere in the language. The same keywords are used to conditionally unwrap</div><div>and bind an item, not just shadow that item's current value.</div><div><br></div><div>Introducing a new <font face="Menlo">bind</font> keyword to indicate unwrapping and binding would disambiguate these uses.</div><div><br></div><div>DETAIL DESIGN:</div><div><br></div><div>Jacob Bandes-Storch offers two common use-cases. I prefer his "if bind foo" to my original "if bind foo = foo":</div><div><br></div><div><div><font face="Menlo"> if bind foo {</font></div><div><font face="Menlo"> // foo is non-optional in here</font></div><div><font face="Menlo"> }</font></div><div><font face="Menlo"><br></font></div><div><font face="Menlo"> somethingAsync { [weak self] in</font></div><div><font face="Menlo"> guard bind self else { return }</font></div><div><font face="Menlo"> // ...</font></div><div><font face="Menlo"> }</font></div></div><div><br></div></div><div>JBS's approach offers my original "bind" keyword to unwrap and shadow bind, but also provides a way to </div><div>strongly bind a weak reference to self, which (presumably) would allow self semantics in the remaining</div><div>lifetime of that scope.</div><div><br></div><div>ALTERNATIVE PROPOSALS:</div><div><br></div><div>Tino Heth proposes a second use-case one with different semantics. This case, it seems to make an</div><div>alias rather than using binding for shadowing:</div><div><br></div><div><font face="Menlo">bind x = a.property.with.a.long.path<br>print x // 42<br>print(a.property.with.a.long.path == 42) => true</font></div><div><span style="font-family:Palatino-Roman"><br></span></div><div><span style="font-family:Palatino-Roman">presumably this means:</span></div><div><span style="font-family:Palatino-Roman"><br></span></div><div><font face="Menlo">x += 1</font></div><div><font face="Menlo">print(a.property.with.a.long.path) // 43</font></div><div><font face="Palatino-Roman"><br></font></div><div><font face="Palatino-Roman">DISCUSSION</font></div><div><font face="Palatino-Roman"><br></font></div><div><font face="Palatino-Roman">I'm throwing these both out there. I have nothing to really say about Tino's but I do think my and Jacob's </font></div><div><font face="Palatino-Roman">proposal has the advantages of:</font></div><div><font face="Palatino-Roman"><br></font></div><div><font face="Palatino-Roman">* Simplifying an mildly complex and potentially misleading statement </font></div><div><font face="Palatino-Roman">* Creating a deliberate and controlled rather than accidental shadowing style</font></div><div><font face="Palatino-Roman"><br></font></div><div><font face="Palatino-Roman">Have at it.</font></div><span><font color="#888888"><div><font face="Palatino-Roman"><br></font></div><div><font face="Palatino-Roman">-- Erica</font></div><div><font face="Palatino-Roman"><br></font></div><div><font face="Palatino-Roman"><br></font></div></font></span></div><br>_______________________________________________<br>
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