<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>I don't like it either, as the "official" way to get that functionality, but that's not what I was suggesting. Those were just a couple off-top-of-my-head examples of what could be done if we had them.</div><div><br></div><div>They could also be used to facilitate "static sequences":</div><div>protocol StaticSequenceType {</div><div>// whatever's in SequenceType, but with "static" in front of everything</div><div>}</div><div>And then w<span style="background-color: rgba(255, 255, 255, 0);">ith a minor change to the "for-in" mechanism, this would become valid:</span></div><div>for foo in SomeType {</div><div>// do stuff</div><div>}</div><div><div><br></div><div id="AppleMailSignature">(Come to think of it, seems like that could help with the proposal to be able to iterate over all cases of an enum, since it'd probably decrease the chances of a naming collision between pre-existing properties and the automatically created code.)</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">Anyway, unless I'm misunderstanding your objection, aside from "letting people do something in an unaesthetic way", I can't really think of a downside.</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">Does anyone know why they're currently disallowed?</div><div id="AppleMailSignature"><br>- Dave Sweeris<br><br></div>On Jan 28, 2016, at 19:36, Félix Cloutier <<a href="mailto:felixcca@yahoo.ca">felixcca@yahoo.ca</a>> wrote:<br><br></div><blockquote type="cite"><div><meta http-equiv="Content-Type" content="text/html charset=utf-8">I don't like that the subscript essentially becomes a second call syntax. Can we solve these problems in a different way?<br class=""><div class="">
<br class="Apple-interchange-newline"><span style="color: rgb(0, 0, 0); font-family: 'Lucida Grande'; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none;" class="">Félix</span>
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<br class=""><div><blockquote type="cite" class=""><div class="">Le 28 janv. 2016 à 22:20:01, Dave via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> a écrit :</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="">What do we think about allowing types to have static subscripts?</div><div class=""><div style="margin: 0px; line-height: normal;" class=""><div style="font-size: 11px; margin: 0px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""><span style="color: rgb(211, 54, 130);" class="">struct</span> Foo {</font></div><div style="font-size: 11px; margin: 0px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">static</span> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">subscript</span>(bar: <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Bar</span>) -> <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">FooBar</span> {...}</font></div><div style="font-size: 11px; margin: 0px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class="">}</font></div><div class=""><br class=""></div><div class="">It could be used to implement umbrella class “initializers” that return subclasses (or anything, really) without relying on Objective-C tomfoolery, since it’s just another function and can return anything you want:</div><div class=""><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""><span style="color: rgb(211, 54, 130); font-size: 11px;" class="">class</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> Int8Class : </span></font><span style="color: rgb(41, 161, 152); font-size: 11px;" class="">SwiftInteger</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> {…}</span></font></font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">class</span> Int16Class : <span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">SwiftInteger</span> { <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">var</span> x: <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int16</span>; <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">override</span> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">init</span>() { <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">self</span>.<span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">x</span> = <span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">0</span> }; <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">init</span>(<span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">_</span> x: <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int16</span>) { <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">self</span>.<span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">x</span> = x } }</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""><span style="color: rgb(211, 54, 130); font-size: 11px;" class="">class</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> Int32Class : </span></font><span style="color: rgb(41, 161, 152); font-size: 11px;" class="">SwiftInteger</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> {…}</span></font></font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""><span style="color: rgb(211, 54, 130); font-size: 11px;" class="">class</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> IntClass : </span></font><span style="color: rgb(41, 161, 152); font-size: 11px;" class="">SwiftInteger</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> {…}</span></font></font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""><span style="color: rgb(211, 54, 130); font-size: 11px;" class="">class</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> BigIntClass : </span></font><span style="color: rgb(41, 161, 152); font-size: 11px;" class="">SwiftInteger</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> {…}</span></font></font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><span style="font-family: FiraMono-Regular; color: rgb(211, 54, 130);" class="">class</span><span style="font-family: FiraMono-Regular;" class=""> SwiftInteger </span><span style="font-family: FiraMono-Regular;" class="">{</span></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> </span></font><span style="color: rgb(211, 54, 130); font-size: 11px;" class="">static</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> </span></font><span style="color: rgb(211, 54, 130); font-size: 11px;" class="">subscript</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class="">() -> </span></font><span style="color: rgb(41, 161, 152); font-size: 11px;" class="">SwiftInteger</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> {…}</span></font></font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> </span></font><span style="color: rgb(211, 54, 130); font-size: 11px;" class="">static</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> </span></font><span style="color: rgb(211, 54, 130); font-size: 11px;" class="">subscript</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class="">(x: </span></font><span style="color: rgb(39, 139, 210); font-size: 11px;" class="">Int8</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class="">) -> </span></font><span style="color: rgb(41, 161, 152); font-size: 11px;" class="">SwiftInteger</span><font color="#93a1a1" class=""><span style="font-size: 11px;" class=""> {…}</span></font></font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" style="color: rgb(147, 161, 161); font-size: 11px;" class=""> <span style="color: rgb(211, 54, 130);" class="">static</span> <span style="color: rgb(211, 54, 130);" class="">subscript</span>(x: <span style="color: rgb(39, 139, 210);" class="">Int16</span>) -> <span style="color: rgb(41, 161, 152);" class="">SwiftInteger</span> {</font><font color="#93a1a1" face="FiraMono-Regular" class=""><span style="font-size: 11px;" class="">…}</span></font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" style="color: rgb(147, 161, 161); font-size: 11px;" class=""> <span style="color: rgb(211, 54, 130);" class="">static</span> <span style="color: rgb(211, 54, 130);" class="">subscript</span>(x: <span style="color: rgb(39, 139, 210);" class="">Int32</span>) -> <span style="color: rgb(41, 161, 152);" class="">SwiftInteger</span> {</font><font color="#93a1a1" face="FiraMono-Regular" class=""><span style="font-size: 11px;" class="">…}</span></font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""> <span style="color: rgb(211, 54, 130);" class="">static</span> <span style="color: rgb(211, 54, 130);" class="">subscript</span>(x: <span style="color: rgb(39, 139, 210);" class="">Int</span>) -> <span style="color: rgb(41, 161, 152);" class="">SwiftInteger</span> {</font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">switch</span> x {</font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">case</span> <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int</span>( <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int8</span>.min)...<span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int</span>( <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int8</span>.max): <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">return</span> <span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">Int8Class</span>(<span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int8</span>(x))</font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">case</span> <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int</span>(<span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int16</span>.min)...<span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int</span>(<span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int16</span>.max): <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">return</span> <span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">Int16Class</span>(<span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int16</span>(x))</font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">case</span> <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int</span>(<span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int32</span>.min)...<span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int</span>(<span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int32</span>.max): <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">return</span> <span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">Int32Class</span>(<span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">Int32</span>(x))</font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">default</span>: <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">return</span> <span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">IntClass</span>(x)</font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""> }</font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><font face="FiraMono-Regular" class=""> }</font></div><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(41, 161, 152);" class=""><span style="font-family: FiraMono-Regular; color: rgb(147, 161, 161);" class="">}</span></div></div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(41, 161, 152);" class=""><font face="FiraMono-Regular" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">let</span><span style="font-variant-ligatures: no-common-ligatures; color: #93a1a1" class=""> foo = </span>SwiftInteger[<span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">256</span>] <span style="color: rgb(203, 75, 22);" class="">//foo is a Int16Class</span></font></div></div><div class=""><br class=""></div><div class="">Or for creating “functions” that have properties:</div><div class=""><div style="margin: 0px; font-size: 11px; line-height: normal; color: rgb(147, 161, 161);" class=""><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""><span style="color: rgb(211, 54, 130);" class="">struct</span> add {</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">static</span> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">let</span> name: <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">String</span> = <span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">"add"</span></font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">static</span> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">var</span> logging = <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">false</span></font></div><div style="margin: 0px; line-height: normal; color: rgb(211, 54, 130);" class=""><font face="FiraMono-Regular" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #93a1a1" class=""> </span>static<span style="font-variant-ligatures: no-common-ligatures; color: #93a1a1" class=""> </span>private (set)<span style="font-variant-ligatures: no-common-ligatures; color: #93a1a1" class=""> </span>var<span style="font-variant-ligatures: no-common-ligatures; color: #93a1a1" class=""> callCount = </span><span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">0</span></font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> <span style="color: rgb(211, 54, 130);" class="">static</span> <span style="color: rgb(211, 54, 130);" class="">subscript</span>(arg1: <span style="color: rgb(39, 139, 210);" class="">Int</span>, arg2: <span style="color: rgb(39, 139, 210);" class="">Int</span>) -> <span style="color: rgb(39, 139, 210);" class="">Int</span> {</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">defer</span> {</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">if</span> <span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">add</span>.logging == <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">true</span> {</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #278bd2" class="">print</span>(<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">"callcount = </span>\<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">(</span><span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">add</span>.callCount<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">): </span>\<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">(</span><span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">add</span>.name<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">)(</span>\<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">(</span>arg1<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">), </span>\<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">(</span>arg2<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">)) -> </span>\<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">(</span>ret<span style="font-variant-ligatures: no-common-ligatures; color: #dc322f" class="">)"</span>)</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> }</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> }</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #29a198" class="">add</span>.callCount += <span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">1</span></font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">let</span> ret = arg1 + arg2</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #d33682" class="">return</span> ret</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""> }</font></div><div style="margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class="">}</font></div></div><div style="margin: 0px; line-height: normal;" class=""><div style="color: rgb(41, 161, 152); font-size: 11px; margin: 0px; line-height: normal;" class=""><span style="font-family: FiraMono-Regular; color: rgb(211, 54, 130);" class="">let</span><span style="font-family: FiraMono-Regular; color: rgb(147, 161, 161);" class=""> nine = </span><font face="FiraMono-Regular" class="">add[<span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">4</span><span style="font-variant-ligatures: no-common-ligatures; color: #93a1a1" class="">, </span><span style="font-variant-ligatures: no-common-ligatures; color: #6c71c4" class="">5</span>]</font></div><div style="color: rgb(147, 161, 161); font-size: 11px; margin: 0px; line-height: normal;" class=""><font face="FiraMono-Regular" class=""><span style="color: rgb(41, 161, 152);" class="">add</span>.logging = <span style="color: rgb(211, 54, 130);" class="">true</span></font></div><div style="margin: 0px; line-height: normal;" class=""><span style="color: rgb(211, 54, 130); font-size: 11px; font-family: FiraMono-Regular;" class="">let</span><span style="color: rgb(147, 161, 161); font-size: 11px; font-family: FiraMono-Regular;" class=""> ten = </span><font face="FiraMono-Regular" class=""><span style="color: rgb(41, 161, 152); font-size: 11px;" class="">add</span><span style="color: rgb(41, 161, 152); font-size: 11px;" class="">[</span><span style="color: rgb(108, 113, 196); font-size: 11px;" class="">4</span><span style="color: rgb(147, 161, 161); font-size: 11px;" class="">, </span><span style="color: rgb(108, 113, 196); font-size: 11px;" class="">6</span><span style="color: rgb(41, 161, 152); font-size: 11px;" class="">]</span><span style="color: rgb(147, 161, 161); font-size: 11px;" class=""> </span><font color="#cb4b16" class=""><span style="font-size: 11px;" class="">// prints “call count = 2: add(4, 6) -> 10"</span></font></font></div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">Thoughts?</div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div></div></div></div></div><div class="">
- Dave Sweeris
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<br class=""></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">https://lists.swift.org/mailman/listinfo/swift-evolution</a><br class=""></div></blockquote></div><br class=""></div></blockquote></body></html>