swift-fcn-ptr-optimization.swift

public final class FancyClass {

    public enum FancyEnum {

        case a
        case b
    }

    public let fancy: FancyEnum
    private let ptrCall: (Double) -> Double

    public init(_ fancy: FancyEnum) {
        self.fancy = fancy

        switch fancy {
        case .a: ptrCall = FancyClass.aCall
        case .b: ptrCall = FancyClass.bCall
        }
    }

    private static func aCall(_ a: Double) -> Double { return a }
    private static func bCall(_ b: Double) -> Double { return b * 2 }

    public func makeCheckedCall(_ a: Double) -> Double {
        switch fancy {
        case .a: return FancyClass.aCall(a)
        case .b: return FancyClass.bCall(a)
        }
    }

    public func makePtrCall(_ a: Double) -> Double {
        return ptrCall(a)
    }
}