GenericDataSource for UITableView

GenericDataSource.swift

//
//  ViewController.swift
//  GenericViewController
//
//  Created by 陳 冠禎 on 16/04/2018.
//  Copyright © 2018 AppCoda. All rights reserved.
//

import UIKit

final class ViewController<T: DataSourceProtocol>: UIViewController, UITableViewDelegate, UITableViewDataSource {
    
    lazy var tableView: UITableView = {
        let myTableView = UITableView(frame: view.frame)
        myTableView.delegate = self
        myTableView.dataSource = self
        return myTableView
        
    }()
    override func viewDidLoad() {
        super.viewDidLoad()
        view = tableView
        tableView.register(UITableViewCell.self,
                           forCellReuseIdentifier: String(describing: UITableViewCell.self))
    }
    
     func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: String(describing: UITableViewCell.self), for: indexPath)
        cell.textLabel?.text = String(describing: T.allCases[indexPath.row])
        return cell
        
    }
     func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return T.allCases.count
    }
}

enum DNA: DataSourceProtocol {
    case A,G,C,T
    
}
protocol CaseIterable : Hashable {
    static var allCases: [Self] { get }
}

protocol DataSourceProtocol: CaseIterable {
    
}

extension CaseIterable {
    
    static var allCases: [Self] {
        let anySequence = AnySequence { () -> AnyIterator<Self> in
            var index = 0
            return AnyIterator {
                let current : Self = withUnsafePointer(to: &index) {
                    
                    return $0.withMemoryRebound(to: self, capacity: 1) {
                        
                        return $0.pointee } }
                
                guard current.hashValue == index else { return nil }
                index += 1
                return current
            }
        }
        return Array(anySequence)
    }
}