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.send { color:#77bb77; }
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.error { color:#AA0000; }</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="bloop_markdown"><p>Lets say (and hope) in some future we’ll be able to write functions like this:</p>
<pre><code class="swift">func foo<T: class>(_: T) { /* do something */ }
func foo<T: enum>(_: T) { /* do something */ }
func foo<T: struct>(_: T) { /* do something */ }
// or we might want to have more than one generic types
func foo<A: class, B: enum, C: struct>(_: A, _: B, _: C) {
// do something better
}
// try to use `where` clause with `class A`, `struct C`. It looks ugly to me.
</code></pre>
<p>So ins’t it better to stick to the original syntax and write code like this!?</p>
<pre><code class="swift">protocol MagicType {} // can be applied to any type
protocol ClassType: class {} // only for classes
protocol StructType: struct {} only for structs
protocol ValueType: struct, enum {}
protocol MixedType: struct, class {}
</code></pre>
<p>This is why in my eyes the current syntax for protocols is just perfect.</p>
<p></p></div><div class="bloop_original_html"><style>body{font-family:Helvetica,Arial;font-size:13px}</style><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> <br> <div id="bloop_sign_1449556337510558208" class="bloop_sign"><div><font face="helvetica, arial">— </font></div><div>Regards Adrian<br></div></div> <br><p class="airmail_on">Am 7. Dezember 2015 bei 23:29:34, Felix Gabel via swift-evolution (<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>) schrieb:</p> <blockquote type="cite" class="clean_bq"><span><div dir="auto"><div></div><div>
<title></title>
<div>Great to hear about being able to apply this to type
parameters and associated types in the future. But I still propose
to rethink the syntax decision. </div>
<div> </div>
<div>class protocol FooType {}</div>
<div><span style="background-color: rgba(255, 255, 255, 0);">typealias class Bar:
FooType</span></div>
<div>func foo<class T>()</div>
<div><br></div>
<div>This is more consistent with for example the declaration of a
class or property</div>
<div><br></div>
<div>Construct name: Type</div>
<div><br>
On 07 Dec 2015, at 23:04, Douglas Gregor via swift-evolution
<<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>>
wrote:<br>
<br></div>
<blockquote type="cite">
<div><br class="">
<div>
<blockquote type="cite" class="">
<div class="">On Dec 7, 2015, at 8:58 AM, Joe Groff via
swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: 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;" class=""><br class="Apple-interchange-newline">
On Dec 7, 2015, at 8:00 AM, Matthew Cheok via swift-evolution
<<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class="">
<br class="">
Currently, we declare class protocols with the following
syntax:<br class="">
<br class="">
protocol TestProtocol: class, OtherProtocol {}<br class="">
<br class="">
This is odd for a few reasons:<br class="">
1) The keyword class exists in the middle of the
declaration<br class="">
2) The keyword class follows the colon and looks a lot like
inheritance<br class="">
3) The keyword class occupies a somewhat arbitrary first position
after the colon (otherwise we have an error)<br class="">
<br class="">
We also have another use of the class keyword as a modifier when
declaring class methods:<br class="">
<br class="">
class func doSomething() {}<br class="">
<br class="">
I’m suggesting a change of syntax that rectifies the above
issues:<br class="">
<br class="">
class protocol TestProtocol: OtherProtocol {}<br class="">
<br class="">
Would love to hear other thoughts on this.<br class=""></blockquote>
<br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: 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;" class="">
<span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: 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; float: none; display: inline !important;" class="">The constraint syntax is used because, in the fullness of
time, it should also be applicable to type parameters and
associated types:</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: 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;" class="">
<br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: 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;" class="">
<span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: 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; float: none; display: inline !important;" class="">protocol Foo { typealias T: class }</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: 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;" class="">
<br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: 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;" class="">
<span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: 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; float: none; display: inline !important;" class="">func foo<T: class>(x: T)</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: 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;" class=""></div>
</blockquote>
</div>
<div class=""><br class=""></div>
Right. This is exactly the reason why we have the syntax
<div class=""><br class=""></div>
<div class="">protocol X : class { … }</div>
<div class=""><br class=""></div>
<div class="">and why I’m against changing the current
syntax.<br class="">
<div class=""><br class=""></div>
<div class="">- Doug</div>
<div class=""><br class=""></div>
</div>
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</blockquote>
<blockquote type="cite">
<div>
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</blockquote>
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