<div dir="ltr">OK, then, I guess, Swift can create type metainfo at runtime, and it must work for <font face="monospace, monospace">Type<T></font>, as well. I'd appreciate this feature.<div><br></div><div>Next, I don't really like the following:<br><div><ul style="margin:15px 0px;font-size:12.8px"><li style="margin:15px 0px"><p style="margin:15px 0px">I’d rename <code style="font-family:Menlo,Consolas,"Liberation Mono",Courier,monospace;font-size:10pt;border-radius:3px;color:inherit;border:1px solid rgb(234,234,234);margin:0px 2px;padding:0px 5px;word-wrap:normal;background-color:rgb(248,248,248)">T.Type</code> to <code style="font-family:Menlo,Consolas,"Liberation Mono",Courier,monospace;font-size:10pt;border-radius:3px;color:inherit;border:1px solid rgb(234,234,234);margin:0px 2px;padding:0px 5px;word-wrap:normal;background-color:rgb(248,248,248)">T.Metatype</code> and produce <code style="font-family:Menlo,Consolas,"Liberation Mono",Courier,monospace;font-size:10pt;border-radius:3px;color:inherit;border:1px solid rgb(234,234,234);margin:0px 2px;padding:0px 5px;word-wrap:normal;background-color:rgb(248,248,248)">typealias Metatype<T> = T.Metatype</code></p></li><li style="margin:15px 0px"><p style="margin:15px 0px">Furthermore <code style="font-family:Menlo,Consolas,"Liberation Mono",Courier,monospace;font-size:10pt;border-radius:3px;color:inherit;border:1px solid rgb(234,234,234);margin:0px 2px;padding:0px 5px;word-wrap:normal;background-color:rgb(248,248,248)">T.Metatype</code> would be disallowed in declarations for the sake of <code style="font-family:Menlo,Consolas,"Liberation Mono",Courier,monospace;font-size:10pt;border-radius:3px;color:inherit;border:1px solid rgb(234,234,234);margin:0px 2px;padding:0px 5px;word-wrap:normal;background-color:rgb(248,248,248)">Metatype<T></code></p></li></ul><div>Why not remove <font face="monospace, monospace">T.Metatype</font><font face="arial, helvetica, sans-serif"> then</font>? <font face="monospace, monospace">Metatype<T></font> will be a special data type that supports referring to static members of <font face="monospace, monospace">T</font>.</div></div></div><div><br></div><div>Next, from "Bikeshedding". The global dictionary will only be able to contain default-constructed <font face="monospace, monospace">Type<T></font> values, but not such as <font face="monospace, monospace">Type<Base>(casting: Derived.self)</font>. How do you deal with those?<br></div><div class="gmail_extra"><br><div class="gmail_quote">2016-07-15 13:47 GMT+03:00 Adrian Zubarev via swift-evolution <span dir="ltr"><<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>></span>:<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><p>Challenge accepted: Fixing your code to make it compile.</p>
<pre><code>typealias SomeGeneric<T> = (T, Int)
func wrap<T>(_ value: T) -> SomeGeneric<T> {
return (value, 42)
}
func recursivelyPrint<T>(_ value: T, depth: Int) {
print(value)
guard depth > 0 else { return }
recursivelyPrint(wrap(value), depth: depth - 1)
}
recursivelyPrint(2.0, depth: 5)
//////////// Output
2.0
(2.0, 42)
((2.0, 42), 42)
(((2.0, 42), 42), 42)
((((2.0, 42), 42), 42), 42)
(((((2.0, 42), 42), 42), 42), 42)
</code></pre>
<p>Technically <code>Type<T></code> should be able to reflect other <code>Type<T></code>’s. There is nothing wrong about it.</p>
<pre><code>let var1 = Int // Type: Type<Int>
let var2 = Int() // Type: Int
let var2 = Type<Int> // Type: Type<Type<Int>> where the metatype inside will be `Type<Int>.Type`
</code></pre>
<p>As you can see there won’t be any implicit infinite recursion.</p>
<p></p></div><div><span class=""><div style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><br></div> <br> <div><div style="font-family:helvetica,arial;font-size:13px">-- <br>Adrian Zubarev<br>Sent with Airmail</div></div> <br></span><span class=""><p>Am 15. Juli 2016 um 12:25:10, Adrian Zubarev (<a href="mailto:adrian.zubarev@devandartist.com" target="_blank">adrian.zubarev@devandartist.com</a>) schrieb:</p> </span><blockquote type="cite"><span><div><span class=""><blockquote style="font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span>> I don't see any problems with Type<Type<T>>. There is finite number of types that are used in the program, and compiler can collect and store information about them all statically. Am I right?<br><br></span>Maybe not:<br><br><font face="monospace, monospace"> func recursivelyPrint<T>(type: T.Type, depth: Int) {<br> print(type)<br> guard depth > 0 else { return }<br> recursivelyPrint(type: type.dynamicType, depth: depth - 1)<br> }<br> recursivelyPrint(type: Int.self, depth: 5)</font></blockquote><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br></div></span><span class=""><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">Great example. But we can adapt it to tuples or any generic type:</div><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br></div><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="monospace, monospace">typealias SomeGeneric<T> = (T, Int)</font></div><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="monospace, monospace">func wrap<T>(_ value: T) -> SomeGeneric<T></font></div><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="monospace, monospace"><br></font></div></span><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="monospace, monospace">func recursivelyPrint<T>(_ value: T, depth: Int) {</font></div><span class=""><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="monospace, monospace"> print(type)</font></div><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="monospace, monospace"> guard depth > 0 else { return }</font></div></span><span class=""><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="monospace, monospace"> recursivelyPrint(wrap(value), depth: delth - 1)</font></div><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="monospace, monospace">}</font></div><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br></div><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">Currently, such code does not compile, because compiler can't create any types dynamically, not only for<span> </span><font face="monospace, monospace">SomeGeneric<T> = T.Type</font>.</div><div style="color:rgb(0,0,0);font-family:'helvetica Neue',helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">So this problem is not specific to Type<T>, and should not be solved separately.</div></span></div></span></blockquote></div><div><p></p></div></div><br>_______________________________________________<br>
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<br></blockquote></div><br></div></div>