Swift Service Locator / IoC Container / Dependency Registry & Resolver (haha gross)

Container.swift

class Container : DependencyRegistry, DependencyResolver {
    
    private var registrations: [String : () -> Any] = [:]
    
    func register<T>(_ t: T.Type, _ f: @escaping @autoclosure () -> T) {
        registrations[key(for: t)] = f
    }
    
    func resolve<T>() -> T {
        registrations[key(for: T.self)]!() as! T
    }
    
    private func key(for type: Any.Type) -> String {
        .init(describing: type)
    }
}

protocol DependencyRegistry {
    func register<T>(_ t: T.Type, _ f: @escaping () -> T)
}

protocol DependencyResolver {
    func resolve<T>() -> T
}

extension DependencyResolver {
    func configure(_ c: (Self) -> Void) -> Self {
        c(self)
        return self
    }
}

let container: Container = .init()
    .configure { c in
        c.register(Interface.self, Implementation.init)
        c.register(OtherInterface.self, HasThreeDependencies(c.resolve, c.resolve, c.resolve)) // Haha yucky gross stinky
    }