Experimenting with Swift's protocols and trees

Protocols_and_trees.swift

protocol HasName {
    var name: String { get }
}

protocol HasSubNodes: HasName {
    var subNodes: [HasName] { get }
}

protocol HasData: HasName {
    var data: String { get }
}

class Folder: HasSubNodes {
    var name: String
    var subNodes = [HasName]()
    
    init(name: String) {
        self.name = name
    }
}

class File: HasData {
    var name: String
    var data: String
    
    init(name: String, andData data: String) {
        self.name = name
        self.data = data
    }
}


let root = Folder(name:"root")
let folder1 = Folder(name:"Folder1")
let file1 = File(name:"File1", andData: "Content of file 1")
let file2 = File(name:"File2", andData: "Content of file 2")
root.subNodes.append(folder1)
root.subNodes.append(file1)
folder1.subNodes.append(file2)
let folder2 = Folder(name:"Folder2")
folder1.subNodes.append(folder2)
let file3 = File(name:"File3", andData: "Content of file 3")
folder2.subNodes.append(file3)

func printTreeForNode(node: HasName, andLevel level: Int) {
    let prefix = String(count: level, repeatedValue: Character("-"))
    print(prefix+node.name)
    if let folder = node as? HasSubNodes {
        for subNode in folder.subNodes {
            printTreeForNode(subNode, andLevel: level+1)
        }
    }
}

printTreeForNode(root, andLevel: 1)