PathsAndCollections.swift

// So from the Objc.io talk, we learn about a way of representing filesystem paths that can point to either files or directories.
// Internally, these are represented as an array of path elements. Let's do that too:
public struct Path<Element> {
    public struct Collection {
        private var components: [String]

        public func child(_ key: String) -> Path<Element> {
            return append(key)
        }

        fileprivate func append<T>(_ args: String ...) -> Path<T> {
            return Path<T>(components + args)
        }

        fileprivate init(_ components: [String]) {
            self.components = components
        }

        public var rendered: String {
            return components.joined(separator: "/")
        }
    }

    private var components: [String]

    fileprivate func append<T>(_ args: String ...) -> Path<T> {
        return Path<T>(components + args)
    }

    fileprivate func append<T>(_ args: String ...) -> Path<T>.Collection {
        return Path<T>.Collection(components + args)
    }

    fileprivate init(_ components: [String]) {
        self.components = components
    }

    public var rendered: String {
        return components.joined(separator: "/")
    }
}