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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>Existentials are still missing in the language. Any advice how to rewrite the code so it still would do its job under the hood?</p>
<pre><code class="swift">protocol Proto : class {
// `A` is a generic type and therefore should stay as an associatedtype
associatedtype A
func performWith(_ a: A)
}
final class SomeType<B> {
typealias ProtoB = Any<Proto> where Proto.A == B
var protos: [ProtoB]
init(_ protos: [ProtoB]) {
self.protos = protos
}
func callProtosWith(_ b: B) {
self.protos.forEach {
$0.performWith(b)
}
}
}
</code></pre>
<p>I could make <code>protocol Proto : BaseProto</code> and safe an array of <code>BaseProto</code> but how do I convert it back to <code>Proto</code> when needed, so I could access <code>performWith(_:)</code> function?</p>
<p>I cannot use the generic parameter list from <code>SomeType</code> to enforce this, because the class that conforms to <code>Proto</code> might not have the same base class, which is the intended behavior.</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_1480675823602920960" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px">-- <br>Adrian Zubarev<br>Sent with Airmail</div></div></div><div class="bloop_markdown"><p></p></div></body></html>