convert didClose to output

Author: watt

Samples/SwiftUITestbed/Sources/AppDelegate.swift

@@ -25,7 +25,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
         window = UIWindow(frame: UIScreen.main.bounds)
         window?.rootViewController = WorkflowHostingController(
-            workflow: RootWorkflow(close: nil)
+            workflow: RootWorkflow()
                 .mapRendering(MarketRootScreen.init)
                 .mapRendering(ModalHostContainer.init)
         )

Samples/SwiftUITestbed/Sources/MainScreen.swift

@@ -28,6 +28,7 @@ struct MainScreen: MarketScreen {
 
     let title: String
     let didChangeTitle: (String) -> Void
+    let canClose: Bool
 
     let allCapsToggleIsOn: Bool
     let allCapsToggleIsEnabled: Bool
@@ -108,7 +109,7 @@ extension MainScreen: MarketBackStackContentScreen {
     func backStackItem(in environment: ViewEnvironment) -> MarketUI.MarketNavigationItem {
         MarketNavigationItem(
             title: .text(.init(regular: title)),
-            backButton: didTapClose.map { .close(onTap: $0) } ?? .automatic()
+            backButton: canClose ? .close(onTap: { didTapClose?() }) : .automatic()
         )
     }
 

Samples/SwiftUITestbed/Sources/MainWorkflow.swift

@@ -18,11 +18,12 @@ import MarketWorkflowUI
 import Workflow
 
 struct MainWorkflow: Workflow {
-    let didClose: (() -> Void)?
+    let canClose: Bool
 
     enum Output {
         case pushScreen
         case presentScreen
+        case close
     }
 
     struct State {
@@ -72,12 +73,13 @@ struct MainWorkflow: Workflow {
         return MainScreen(
             title: state.title,
             didChangeTitle: { sink.send(.changeTitle($0)) },
+            canClose: canClose,
             allCapsToggleIsOn: state.isAllCaps,
             allCapsToggleIsEnabled: !state.title.isEmpty,
             didChangeAllCapsToggle: { sink.send(.changeAllCaps($0)) },
             didTapPushScreen: { sink.send(.pushScreen) },
             didTapPresentScreen: { sink.send(.presentScreen) },
-            didTapClose: didClose
+            didTapClose: canClose ? { sink.send(.close) } : nil
         )
     }
 }

Samples/SwiftUITestbed/Sources/RootWorkflow.swift

@@ -19,9 +19,9 @@ import Workflow
 import WorkflowUI
 
 struct RootWorkflow: Workflow {
-    let close: (() -> Void)?
-
-    typealias Output = Never
+    enum Output {
+        case close
+    }
 
     struct State {
         var backStack: BackStack
@@ -57,6 +57,8 @@ struct RootWorkflow: Workflow {
                 state.backStack.other.append(.main())
             case .main(.presentScreen):
                 state.isPresentingModal = true
+            case .main(.close):
+                return .close
             case .popScreen:
                 state.backStack.other.removeLast()
             case .dismissScreen:
@@ -75,7 +77,7 @@ struct RootWorkflow: Workflow {
         func rendering(_ screen: State.Screen, isRoot: Bool) -> AnyMarketBackStackContentScreen {
             switch screen {
             case .main(let id):
-                return MainWorkflow(didClose: isRoot ? close : nil)
+                return MainWorkflow(canClose: isRoot)
                     .mapOutput(Action.main)
                     .mapRendering(AnyMarketBackStackContentScreen.init)
                     .rendered(in: context, key: id.uuidString)
@@ -96,7 +98,13 @@ struct RootWorkflow: Workflow {
             base: backStack,
             modals: {
                 guard state.isPresentingModal else { return [] }
-                let screen = RootWorkflow(close: { sink.send(.dismissScreen) })
+                let screen = RootWorkflow()
+                    .mapOutput { output in
+                        switch output {
+                        case .close:
+                            return Action.dismissScreen
+                        }
+                    }
                     .rendered(in: context)
                     .asAnyScreen()
                 let modal = Modal(