dynamic invocation in swift

invoke.swift

func wrap<A, B, C>(f: A -> B -> C) -> (A -> Any -> Any) {
    return { a1 in { a2 in f(a1)(a2 as! B) } }
}

protocol Dynamic {
    static var functions: [Selector: Self -> Any -> Any] { get }
    func dynamicInvoke(f: Selector, arg: Any) -> Any
}

extension Dynamic {
    func dynamicInvoke(f: Selector, arg: Any) -> Any {
        return Self.functions[f]?(self)(arg)
    }
}

final class A: Dynamic {
    static var functions: [Selector : A -> Any -> Any] = [
        #selector(A.a): wrap(A.a),
        #selector(A.b(_:)): wrap(A.b),
        #selector(A.c(_:c2:)): wrap(A.c)
    ]

    @objc func a() {
        print("a")
    }

    @objc func b(b: String) {
        print(b)
    }

    @objc func c(c: String, c2: Int) {
        for _ in 0..<c2 {
            print(c)
        }
    }
}

A().dynamicInvoke(#selector(A.a), arg: ())
A().dynamicInvoke(#selector(A.b(_:)), arg: "b")
A().dynamicInvoke(#selector(A.c(_:c2:)), arg: ("c", 2))

微妙

Great