Merge pull request #992 from square/dhaval/viewRegistryDocs

Update docs to reflect ViewRegistry removal:

docs/tutorial/building-a-view-controller-from-screen.md

@@ -18,9 +18,9 @@ class DemoScreenViewController: ScreenViewController<DemoScreen> {
 
     private let button: UIButton
 
-    required init(screen: DemoScreen, viewRegistry: ViewRegistry) {
+    required init(screen: DemoScreen) {
         button = UIButton()
-        super.init(screen: screen, viewRegistry: viewRegistry)
+        super.init(screen: screen)
 
         update(screen: screen)
     }

docs/tutorial/using-a-workflow-for-ui.md

@@ -14,16 +14,12 @@ public final class ContainerViewController<Output, ScreenType>: UIViewController
     /// Emits output events from the bound workflow.
     public let output: Signal<Output, Never>
 
-    public convenience init<W: Workflow>(workflow: W, viewRegistry: ViewRegistry) where W.Rendering == ScreenType, W.Output == Output
+    public convenience init<W: Workflow>(workflow: W) where W.Rendering == ScreenType, W.Output == Output
 }
 
 ```
 
-The first initializer argument is the workflow that will drive your application.
-
-The second initializer argument is the view registry. The view registry acts as a mapping between
-the view models (`Screen`s) that your workflow emits and the concrete UI implementations that should
-be used to display them.
+The initializer argument is the workflow that will drive your application.
 
 ```swift
 import UIKit
@@ -38,11 +34,9 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
         let window = UIWindow(frame: UIScreen.main.bounds)
 
-        var viewRegistry = ViewRegistry()
-
         let container = ContainerViewController(
-            workflow: DemoWorkflow(),
-            viewRegistry: viewRegistry)
+            workflow: DemoWorkflow()
+        )
 
         window.rootViewController = container
         self.window = window
@@ -53,21 +47,6 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
 
 ```
 
-Your project should compile at this point. It will crash as soon as the workflow emits a screen,
-however, because we have not registered any UI implementations with the view registry. Let's fix
-that:
-
-```swift
-var viewRegistry = ViewRegistry()
-
-// Register the DemoScreenViewController to be responsible for DemoScreen.
-viewRegistry.register(screenViewControllerType: DemoScreenViewController.self)
-
-let container = ContainerViewController(
-    workflow: DemoWorkflow(),
-    viewRegistry: viewRegistry)
-```
-
 Now, when the `ContainerViewController` is shown, it will start the workflow and `render` will be
-called returning the `DemoScreen`. The container will use the view registry to map the `DemoScreen`
-to a `DemoScreenViewController` and add it to the view hierarchy to display.
+called returning the `DemoScreen`. The container will use `viewControllerDescription` to build
+a `DemoScreenViewController` and add it to the view hierarchy to display.

swift/Samples/Tutorial/Tutorial1.md

@@ -43,6 +43,10 @@ struct WelcomeScreen: Screen {
     var onNameChanged: (String) -> Void
     /// Callback when the login button is tapped.
     var onLoginTapped: () -> Void
+
+    var viewControllerDescription: ViewControllerDescription {
+        return WelcomeViewController.description(for: self)
+    }
 }
 ```
 
@@ -54,9 +58,9 @@ import TutorialViews
 final class WelcomeViewController: ScreenViewController<WelcomeScreen> {
     var welcomeView: WelcomeView
 
-    required init(screen: WelcomeScreen, viewRegistry: ViewRegistry) {
+    required init(screen: WelcomeScreen) {
         self.welcomeView = WelcomeView(frame: .zero)
-        super.init(screen: screen, viewRegistry: viewRegistry)
+        super.init(screen: screen)
         update(with: screen)
     }
 
@@ -122,24 +126,16 @@ public final class TutorialContainerViewController: UIViewController {
     let containerViewController: UIViewController
 
     public init() {
-        // Create a view registry. This will allow the infrastructure to map `Screen` types to their respective view controller type.
-        var viewRegistry = ViewRegistry()
-        // Register the `WelcomeScreen` and view controller with the convenience method the template provided.
-        viewRegistry.registerWelcomeScreen()
-
-        // Create a `ContainerViewController` with the `WelcomeWorkflow` as the root workflow, with the view registry we just created.
+        // Create a `ContainerViewController` with the `WelcomeWorkflow` as the root workflow.
         containerViewController = ContainerViewController(
-            workflow: WelcomeWorkflow(),
-            viewRegistry: viewRegistry)
+            workflow: WelcomeWorkflow()
+        )
 
         super.init(nibName: nil, bundle: nil)
     }
 ```
 
-We did a few things here.
-- We created a *view registry* that is used to map screen types to view controllers. The view registry is used by the container to determine what view controller to instantiate the first time we see a screen.
-- We registered our `WelcomeScreen` with the view registry so we have that mapping.
-- We created our `ContainerViewController` with the `WelcomeWorkflow` as the root.
+Now, we've created our `ContainerViewController` with the `WelcomeWorkflow` as the root.
 
 We can finally run the app again! It will look the exact same as before, but now powered by our workflow.
 

swift/Samples/Tutorial/Tutorial2.md

@@ -30,15 +30,19 @@ struct TodoListScreen: Screen {
 
     // It should also contain callbacks for any UI events, for example:
     // var onButtonTapped: () -> Void
+
+    // It should also return viewControllerDescription property that 
+    // describes the UIViewController that will be used for rendering 
+    // the screen.
 }
 
 
 final class TodoListViewController: ScreenViewController<TodoListScreen> {
     let todoListView: TodoListView
 
-    required init(screen: TodoListScreen, viewRegistry: ViewRegistry) {
+    required init(screen: TodoListScreen) {
         self.todoListView = TodoListView(frame: .zero)
-        super.init(screen: screen, viewRegistry: viewRegistry)
+        super.init(screen: screen)
         update(with: screen)
     }
 
@@ -77,28 +81,21 @@ extension TodoListWorkflow {
 
 ### Showing the new screen and workflow
 
-For now, let's just show this new screen instead of the login screen/workflow. Update the `TutorialContainerViewController` to register to the new screen and show the `TodoListWorkflow`:
+For now, let's just show this new screen instead of the login screen/workflow. Update the `TutorialContainerViewController` to show the `TodoListWorkflow`:
 
 ```swift
 public final class TutorialContainerViewController: UIViewController {
     let containerViewController: UIViewController
 
     public init() {
-        // Create a view registry. This will allow the infrastructure to map `Screen` types to their respective view controller type.
-        var viewRegistry = ViewRegistry()
-        // Register the `WelcomeScreen` and view controller with the convenience method the template provided.
-        viewRegistry.registerWelcomeScreen()
-        // Register the `TodoListScreen` and view controller with the convenience method the template provided.
-        viewRegistry.registerTodoListScreen()
-
-        // Create a `ContainerViewController` with the `WelcomeWorkflow` as the root workflow, with the view registry we just created.
+        // Create a `ContainerViewController` with the `WelcomeWorkflow` as the root workflow.
 //        containerViewController = ContainerViewController(
-//            workflow: WelcomeWorkflow(),
-//            viewRegistry: viewRegistry)
+//            workflow: WelcomeWorkflow()
+//        )
         // Show the TodoList Workflow instead:
         containerViewController = ContainerViewController(
-            workflow: TodoListWorkflow(),
-            viewRegistry: viewRegistry)
+            workflow: TodoListWorkflow()
+        )
 
         super.init(nibName: nil, bundle: nil)
     }
@@ -236,10 +233,10 @@ public final class TutorialContainerViewController: UIViewController {
     public init() {
         // ...
 
-        // Create a `ContainerViewController` with the `RootWorkflow` as the root workflow, with the view registry we just created.
+        // Create a `ContainerViewController` with the `RootWorkflow` as the root workflow.
         containerViewController = ContainerViewController(
-            workflow: RootWorkflow(),
-            viewRegistry: viewRegistry)
+            workflow: RootWorkflow()
+        )
 
         super.init(nibName: nil, bundle: nil)
     }
@@ -474,7 +471,7 @@ This works, but with no animation between the two screens it's pretty unsatisfyi
 
 ### Back Stack and "Containers"
 
-We want to put our different screens in a navigation controller. Because we want all of our navigation state to be declarative, we need to use the `BackStackContainer` to do this - by registering and using the `BackStackScreen`:
+We want to put our different screens in a navigation controller. Because we want all of our navigation state to be declarative, we need to use the `BackStackContainer` to do this - by using the `BackStackScreen`:
 
 ```swift
 public struct BackStackScreen: Screen {
@@ -488,8 +485,6 @@ public struct BackStackScreen: Screen {
 
 The `BackStackScreen` contains a list of all screens in the back stack that are specified on each render pass.
 
-Register the `BackStackScreen` so that we can use it in the TutorialContainerViewController:
-
 ```swift
 import UIKit
 import Workflow
@@ -501,19 +496,10 @@ public final class TutorialContainerViewController: UIViewController {
     let containerViewController: UIViewController
 
     public init() {
-        // Create a view registry. This will allow the infrastructure to map `Screen` types to their respective view controller type.
-        var viewRegistry = ViewRegistry()
-        // Register the `WelcomeScreen` and view controller with the convenience method the template provided.
-        viewRegistry.registerWelcomeScreen()
-        // Register the `TodoListScreen` and view controller with the convenience method the template provided.
-        viewRegistry.registerTodoListScreen()
-        // Register the `BackStackContainer`, which provides a container for the `BackStackScreen`.
-        viewRegistry.registerBackStackContainer()
-
-        // Create a `ContainerViewController` with the `RootWorkflow` as the root workflow, with the view registry we just created.
+        // Create a `ContainerViewController` with the `RootWorkflow` as the root workflow.
         containerViewController = ContainerViewController(
-            workflow: RootWorkflow(),
-            viewRegistry: viewRegistry)
+            workflow: RootWorkflow()
+        )
 
         super.init(nibName: nil, bundle: nil)
     }

swift/Samples/Tutorial/Tutorial3.md

@@ -48,10 +48,10 @@ final class TodoEditViewController: ScreenViewController<TodoEditScreen> {
     // The `todoEditView` has all the logic for displaying the todo and editing.
     let todoEditView: TodoEditView
 
-    required init(screen: TodoEditScreen, viewRegistry: ViewRegistry) {
+    required init(screen: TodoEditScreen) {
         self.todoEditView = TodoEditView(frame: .zero)
 
-        super.init(screen: screen, viewRegistry: viewRegistry)
+        super.init(screen: screen)
         update(with: screen)
     }
 
@@ -85,6 +85,16 @@ struct TodoEditScreen: Screen {
 }
 ```
 
+The `Screen` protocol also requires a `viewControllerDescription` property. This describes the `UIViewController` that will be used to render the screen:
+
+```swift
+extension TodoEditScreen {
+    var viewControllerDescription: ViewControllerDescription {
+        TodoEditViewController.description(for: self)
+    }
+}
+```
+
 Then update the view with the data from the screen:
 
 ```swift
@@ -106,35 +116,6 @@ final class TodoEditViewController: ScreenViewController<TodoEditScreen> {
 }
 ```
 
-Finally, register the `TodoEditScreen` in the `TutorialContainerViewController` with the viewRegistry:
-
-```swift
-public final class TutorialContainerViewController: UIViewController {
-    let containerViewController: UIViewController
-
-    public init() {
-        // Create a view registry. This will allow the infrastructure to map `Screen` types to their respective view controller type.
-        var viewRegistry = ViewRegistry()
-        // Register the `WelcomeScreen` and view controller with the convenience method the template provided.
-        viewRegistry.registerWelcomeScreen()
-        // Register the `TodoListScreen` and view controller with the convenience method the template provided.
-        viewRegistry.registerTodoListScreen()
-        // Register the `BackStackContainer`, which provides a container for the `BackStackScreen`.
-        viewRegistry.registerBackStackContainer()
-        // Register the `TodoEditScreen` and view controller with the convenience method the template provided.
-        viewRegistry.registerTodoEditScreen()
-
-        // Create a `ContainerViewController` with the `RootWorkflow` as the root workflow, with the view registry we just created.
-        containerViewController = ContainerViewController(
-            workflow: RootWorkflow(),
-            viewRegistry: viewRegistry)
-
-        super.init(nibName: nil, bundle: nil)
-    }
-
-    // ... rest of the implementation ...
-```
-
 #### TodoEditWorkflow
 
 Now that we have our screen and view controller, update the `TodoEditWorkflow` to emit this screen as the rendering.

swift/Tooling/Templates/Screen (View Controller).xctemplate/___FILEBASENAME___Screen.swift

@@ -9,13 +9,17 @@ struct ___VARIABLE_productName___Screen: Screen {
 
     // It should also contain callbacks for any UI events, for example:
     // var onButtonTapped: () -> Void
+
+    var viewControllerDescription: ViewControllerDescription {
+        return ___VARIABLE_productName___ViewController.description(for: self)
+    }
 }
 
 
 final class ___VARIABLE_productName___ViewController: ScreenViewController<___VARIABLE_productName___Screen> {
 
-    required init(screen: ___VARIABLE_productName___Screen, viewRegistry: ViewRegistry) {
-        super.init(screen: screen, viewRegistry: viewRegistry)
+    required init(screen: ___VARIABLE_productName___Screen) {
+        super.init(screen: screen)
         update(with: screen)
     }
 
@@ -28,12 +32,3 @@ final class ___VARIABLE_productName___ViewController: ScreenViewController<___VA
     }
 
 }
-
-
-extension ViewRegistry {
-
-    public mutating func register___VARIABLE_productName___Screen() {
-        self.register(screenViewControllerType: ___VARIABLE_productName___ViewController.self)
-    }
-
-}