tree.swift

protocol Node: Hashable {
    var localizedName: String {get set}

}

class File: Node {
    let fileID: Int
    var localizedName: String
    let hashValue : Int
    
    init(fileID: Int, localizedName: String) {
        self.localizedName = localizedName
        self.fileID = fileID
        self.hashValue = fileID
    }
      }

func ==(lhs: File, rhs: File) -> Bool {
    return lhs.fileID == rhs.fileID
}

func ==(lhs: Folder, rhs: Folder) -> Bool {
    return lhs.folderID == rhs.folderID
}


class Folder : Node {
    var files:Set<File>
    var folders:Set<Folder>
    var localizedName: String
    let folderID: String
    let hashValue : Int
    var children : [AnyObject] {get {return Array(self.files) as [AnyObject] + Array(self.folders)  as [AnyObject]}}

    
    init(folderID: String, localizedName: String) {
        self.localizedName = localizedName
        self.folderID = folderID
        self.files = []
        self.folders = []
        self.hashValue = 0
    }

    func addFile(file:File) -> Void {
        self.files.insert(file)
    }

    func addFolder(folder:Folder) -> Void {
        self.folders.insert(folder)
    }

}

var topLevelFolder = Folder(folderID: "top", localizedName: "Top")

var subFolder = Folder(folderID: "subfolder", localizedName: "Sub Folder")
var subFile = File(fileID: 1, localizedName: "A File")

topLevelFolder.addFolder(subFolder)
topLevelFolder.addFile(subFile)

topLevelFolder.children.count //Should be 2

// Should not actually add subFile again.
topLevelFolder.addFile(subFile)
//print(topLevelNode.children)
topLevelFolder.children.count //Should still be 2