<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>It seem to me we are debating the <i>how</i> of a <i><b>what</b></i> that has not been defined. The root question behind all these alternatives seems to be to decide if the existential-ness should be carried by a 'container' that is then refined internally, or derived from the presence of the <i>free-floating</i> refinements. This is the question that splits the possible syntaxes into these 2 groups:</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">Any<> Any[]</div><div id="AppleMailSignature">Type<> Type<> </div><div id="AppleMailSignature">Existential<></div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">and the (these are all straw man representations that should not limit the thinking)</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">P & Q</div><div id="AppleMailSignature">@P and @Q</div><div id="AppleMailSignature">is P , Q</div><div id="AppleMailSignature">P & Q typed</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">If the answer is to use a 'container' then the next question is to see its relationship to the other existing containers: is it the result of a transformation, is it a superset, or a super type; it is obviously lossy, but not entirely if the solution follows in some of Brent's past suggestion to make some existential types instantiate-able (which opens a very similar problem to what java faced for several years when trying to identify a universal collection literal syntax).</div><div id="AppleMailSignature">That will narrow down the field of possible matches... until one syntax emerges as conveying the meaning that is reflected by the answers to each question.</div><div><br>On May 27, 2016, at 10:55 AM, Thorsten Seitz via swift-evolution <<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>> wrote:<br><br></div><blockquote type="cite"><div><meta http-equiv="Content-Type" content="text/html charset=utf-8">We could just write<div class=""><br class=""></div><div class="">let x: P & Q</div><div class="">instead of</div><div class="">let x: Any<P, Q></div><div class=""><br class=""></div><div class="">let x: Collection where .Element: P</div><div class="">instead of</div><div class="">let x: Any<Collection where .Element: P></div><div class=""><br class=""></div><div class="">let x: P & Q where P.T == Q.T</div><div class="">instead of</div><div class="">let x: Any<P, Q where P.T == Q.T></div><div class=""><br class=""></div><div class="">let x: P & Q & R</div><div class="">instead of</div><div class="">let x: Any<P, Q, R></div><div class=""><br class=""></div><div class="">let x: Collection</div><div class="">instead of</div><div class="">let x: Any<Collection></div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">This would avoid the confusion of Any<T1, T2> being something completely different than a generic type (i.e. order of T1, T2 does not matter whereas for generic types it is essential).</div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">-Thorsten</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">Am 26.05.2016 um 20:11 schrieb Adrian Zubarev via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>>:</div><br class="Apple-interchange-newline"><div class=""><div class="bloop_markdown" style="font-family: Helvetica, Arial; font-size: 13px; 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; background-color: rgb(254, 254, 254);"><p style="margin: 15px 0px; -webkit-margin-before: 0px;" class="">Something like<span class="Apple-converted-space"> </span><code style="font-family: Menlo, Consolas, 'Liberation Mono', Courier, monospace; font-size: 10pt; border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; background-color: rgb(248, 248, 248); color: inherit; border: 1px solid rgb(234, 234, 234); margin: 0px 2px; padding: 0px 5px; word-break: normal; word-wrap: normal; -webkit-margin-before: 0px;" class="">type<…></code><span class="Apple-converted-space"> </span>was considered at the very start of the whole discussion (<a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160502/016523.html" style="color: rgb(65, 131, 196); background-color: inherit; text-decoration: none;" class="">in this thread</a>), but it does not solve the meaning of an existential type and also might lead to even more confusion.<span class="Apple-converted-space"> </span></p><p style="margin: 15px 0px;" class="">From my perspective I wouldn’t use parentheses here because it looks more like an init without any label<span class="Apple-converted-space"> </span><code style="font-family: Menlo, Consolas, 'Liberation Mono', Courier, monospace; font-size: 10pt; border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; background-color: rgb(248, 248, 248); color: inherit; border: 1px solid rgb(234, 234, 234); margin: 0px 2px; padding: 0px 5px; word-break: normal; word-wrap: normal; -webkit-margin-before: 0px;" class="">Type.init(…)</code><span class="Apple-converted-space"> </span>or<span class="Apple-converted-space"> </span><code style="font-family: Menlo, Consolas, 'Liberation Mono', Courier, monospace; font-size: 10pt; border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; background-color: rgb(248, 248, 248); color: inherit; border: 1px solid rgb(234, 234, 234); margin: 0px 2px; padding: 0px 5px; word-break: normal; word-wrap: normal;" class="">Type(…)</code>. I could live with<span class="Apple-converted-space"> </span><code style="font-family: Menlo, Consolas, 'Liberation Mono', Courier, monospace; font-size: 10pt; border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; background-color: rgb(248, 248, 248); color: inherit; border: 1px solid rgb(234, 234, 234); margin: 0px 2px; padding: 0px 5px; word-break: normal; word-wrap: normal;" class="">Any[…]</code><span class="Apple-converted-space"> </span>but this doesn’t look shiny and Swifty to me. Thats only my personal view. ;)</p><div style="margin: 15px 0px;" class=""><br class="webkit-block-placeholder"></div></div><div class="bloop_original_html" style="font-family: Helvetica, Arial; font-size: 13px; 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; background-color: rgb(254, 254, 254);"><div id="bloop_customfont" style="font-family: Helvetica, Arial; font-size: 13px; margin: 0px;" class=""><br class=""></div><br class=""><div id="bloop_sign_1464285716927451136" class="bloop_sign"><div style="font-family: helvetica, arial; font-size: 13px;" class="">-- <br class="">Adrian Zubarev<br class="">Sent with Airmail</div></div><br class=""><p class="airmail_on" style="margin: 15px 0px;">Am 26. Mai 2016 bei 19:48:04, Vladimir.S via swift-evolution (<a href="mailto:swift-evolution@swift.org" style="color: rgb(65, 131, 196); background-color: inherit; text-decoration: none;" class="">swift-evolution@swift.org</a>) schrieb:</p><blockquote type="cite" class="clean_bq" style="margin: 15px 0px;"><span style="margin-top: 0px; margin-bottom: 0px;" class=""><div class=""><div class=""></div><div class="">Don't think {} is better here, as they also have "established meaning in<span class="Apple-converted-space"> </span><br class="">Swift today".<br class=""><br class="">How about just Type(P1 & P2 | P3) - as IMO we can think of such<span class="Apple-converted-space"> </span><br class="">construction as "creation" of new type and `P1 & P2 | P3` could be treated<span class="Apple-converted-space"> </span><br class="">as parameters to initializer.<br class=""><br class="">func f(t: Type(P1 & P2 | P3)) {..}<br class=""><br class=""><br class="">On 26.05.2016 20:32, L. Mihalkovic via swift-evolution wrote:<br class="">> How about something like Type{P1 & P2 | P3} the point being that "<...>" has an established meaning in Swift today which is not what is expressed in the "<P1,P2,P3>" contained inside Any<P1, P2,P3>.<br class="">><br class="">>> On May 26, 2016, at 7:11 PM, Dave Abrahams via swift-evolution <<a href="mailto:swift-evolution@swift.org" style="color: rgb(65, 131, 196); background-color: inherit; text-decoration: none;" class="">swift-evolution@swift.org</a>> wrote:<br class="">>><br class="">>><br class="">>>> on Thu May 26 2016, Adrian Zubarev <<a href="mailto:swift-evolution@swift.org" style="color: rgb(65, 131, 196); background-color: inherit; text-decoration: none;" class="">swift-evolution@swift.org</a>> wrote:<br class="">>>><br class="">>>> There is great feedback going on here. I'd like to consider a few things here:<br class="">>>><br class="">>>> * What if we name the whole thing `Existential<>` to sort out all<br class="">>>> confusion?<br class="">>><br class="">>> Some of us believe that “existential” is way too theoretical a word to<br class="">>> force into the official lexicon of Swift. I think “Any<...>” is much<br class="">>> more conceptually accessible.<br class="">>><br class="">>>><br class="">>>> This would allow `typealias Any = Existential<>`. * Should<br class="">>>> `protocol A: Any<class>` replace `protocol A: class`? Or at least<br class="">>>> deprecate it. * Do we need `typealias AnyClass = Any<class>` or do we<br class="">>>> want to use any class requirement existential directly? If second, we<br class="">>>> will need to allow direct existential usage on protocols (right now we<br class="">>>> only can use typealiases as a worksround).<br class="">>><br class="">>> --<br class="">>> Dave<br class="">>><br class="">>> _______________________________________________<br class="">>> swift-evolution mailing list<br class="">>><span class="Apple-converted-space"> </span><a href="mailto:swift-evolution@swift.org" style="color: rgb(65, 131, 196); background-color: inherit; text-decoration: none;" class="">swift-evolution@swift.org</a><br class="">>><span class="Apple-converted-space"> </span><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" style="color: rgb(65, 131, 196); background-color: inherit; text-decoration: none;" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a><br class="">> _______________________________________________<br class="">> swift-evolution mailing list<br class="">><span class="Apple-converted-space"> </span><a href="mailto:swift-evolution@swift.org" style="color: rgb(65, 131, 196); 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