<html><head><style>body{font-family:Helvetica,Arial;font-size:13px}</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Concerning extension constraining, it’s already doable with:</div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">```</div><div id="bloop_customfont" style="margin: 0px;"><div id="bloop_customfont" style="margin: 0px;">protocol DoubleProtocol {}</div><div id="bloop_customfont" style="margin: 0px;"><br></div><div id="bloop_customfont" style="margin: 0px;">extension Double : DoubleProtocol {}</div><div id="bloop_customfont" style="margin: 0px;"><br></div><div id="bloop_customfont" style="margin: 0px;">extension Array where Element : DoubleProtocol {</div><div id="bloop_customfont" style="margin: 0px;"> func onlyForDoubles() -> String {</div><div id="bloop_customfont" style="margin: 0px;"> return "hello doubles!"</div><div id="bloop_customfont" style="margin: 0px;"> }</div><div id="bloop_customfont" style="margin: 0px;">}</div><div id="bloop_customfont" style="margin: 0px;"><br></div><div id="bloop_customfont" style="margin: 0px;">[1.2].onlyForDoubles() // „hello doubles!”</div><div id="bloop_customfont" style="margin: 0px;">["a"].onlyForDoubles() // error: type of expression is ambiguous without more context</div><div id="bloop_customfont" style="margin: 0px;">```</div><div id="bloop_customfont" style="margin: 0px;"><br></div><div id="bloop_customfont" style="margin: 0px;">However, I personally like the idea of making a syntactic sugar for that case.</div><div id="bloop_customfont" style="margin: 0px;"><br></div><div id="bloop_customfont" style="margin: 0px;">All the best,</div><div id="bloop_customfont" style="margin: 0px;">Krzysztof</div></div> <br> <div id="bloop_sign_1449489930156427776" class="bloop_sign"></div> <br><p class="airmail_on">On 7 December 2015 at 13:01:11, Krzysztof Siejkowski (<a href="mailto:krzysztof@siejkowski.net">krzysztof@siejkowski.net</a>) wrote:</p> <blockquote type="cite" class="clean_bq"><span><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div></div><div>
<title></title>
<div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">
Concerning generic typealiases, the topic is already being
discussed in „Generic `typealias`s” thread: <a href="https://lists.swift.org/pipermail/swift-evolution/2015-December/000132.html">https://lists.swift.org/pipermail/swift-evolution/2015-December/000132.html</a>.
The core Swift team approves:</div>
<div id="bloop_sign_1449489099373719808" class="bloop_sign">
<div id="bloop_customfont" style="margin: 0px;"><br></div>
<div id="bloop_customfont" style="margin: 0px;">
> <span style="white-space: pre-wrap;">Yes, this is
definitely something that I (at least) would like to see. Patches
welcome :-)</span></div>
<div id="bloop_customfont" style="margin: 0px;">> Chris
(Lattner)</div>
<div id="bloop_customfont" style="margin: 0px;"><br></div>
<div id="bloop_customfont" style="margin: 0px;">All the best,</div>
<div>Krzysztof</div>
<div><br></div>
</div>
<p class="airmail_on">On 7 December 2015 at 12:41:05, Tuur Anton
via swift-evolution (<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>)
wrote:</p>
<blockquote type="cite" class="clean_bq">
<div>
<div>
<div><span>Can you please add these features in Swift
3?</span></div>
<div><span><br></span></div>
<div><span>1. The ability to do this:</span></div>
<div><span>extension Array<Double> {</span></div>
<div><span> //extend arrays of doubles</span></div>
<div><span>}</span></div>
<div><span><br></span></div>
<div><span>2. Generic typealiases:</span></div>
<div><span>struct Foo<T,V> {</span></div>
<div><span> let t: T</span></div>
<div><span> let v: V</span></div>
<div><span>}</span></div>
<div><span>typealias IntFoo<V> = Foo<Int,V> //Error in
Swift 2.1</span></div>
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</blockquote>
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