[swift-users] How to rewrite this snippet without `existentials`?

[Adrian Zubarev]

For anyone interested. The correct idea should go into this direction one day:

public class Router<B> {
     
    open protocol Connection<T> : class {
        var router: Router<T> { get set }
        func performWith(_ value: T)
    }
     
    var _connections: [Connection<B>] = []
     
    public typealias Connections = Any<Collection> where Collection.Index == Int, Collection.Iterator.Element == B
     
    // Immutable view without `append` etc.
    public connections: Connections { return self._connections }
     
    public func register(_ connection: Connection<B>) { … }  
     
    public func performWith(_ value: B) {
        self._connections.forEach { $0.performWith(value) }
    }
}
The main idea is to link different nodes (class instances) and call a function on the other end with a specific type parameter. Enums with associated types would come really handy here.



-- 
Adrian Zubarev
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Am 2. Dezember 2016 um 17:35:25, Tino Heth (2th at gmx.de) schrieb:


Thanks, that works party as needed but I just realize this main idea here is exactly an example where one would need generic protocols
That's right — and I guess they rank quite hight on the general evolution-wishlist ;-)
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