Configurable

configurable.swift

typealias ConfigurationClosure<T> = (inout T) throws -> Void

protocol Configurable {}

extension Configurable {
    func configure(_ step: ConfigurationClosure<Self>) rethrows -> Self  {
        var mutableSelf = self
        try step(&mutableSelf)
        return mutableSelf
    }
}

extension URL: Configurable {}

let a = URL(string: "whatever")?.configure {
    $0.appendPathComponent("api")
}

func addingAPIPath(url: inout URL) {
    url.appendingPathComponent("api")
}


let b = URL(string: "whatever")?
    .configure(addingAPIPath)