Add window object for closing

Sources/Core/Window/Window.swift

@@ -15,7 +15,7 @@ public struct Window: MacSceneElement {
     /// The window's identifier.
     public var id: String
     /// The window's content.
-    var content: Body
+    var content: (MacWindow) -> Body
     /// Whether an instance of the window type should be opened when the app is starting up.
     var `open`: Int
     /// The window's title.
@@ -36,14 +36,32 @@ public struct Window: MacSceneElement {
     ///   - open: The number of instances of the window type when the app is starting.
     ///   - content: The window's content.
     ///   - title: The window's title.
-    public init(_ title: String = "", id: String, `open`: Int = 1, @ViewBuilder content: @escaping () -> Body) {
+    public init(
+        _ title: String = "",
+        id: String,
+        `open`: Int = 1,
+        @ViewBuilder content: @escaping (MacWindow) -> Body
+    ) {
         self.title = title
-        self.content = content()
+        self.content = content
         self.id = id
         self.open = open
     }
     // swiftlint:enable function_default_parameter_at_end
 
+    /// The window type.
+    public struct MacWindow {
+
+        /// The window.
+        var window: NSWindow
+
+        /// Close the window.
+        public func close() {
+            window.close()
+        }
+
+    }
+
     /// Set up the initial scene storages.
     /// - Parameter app: The app storage.
     public func setupInitialContainers<Storage>(app: Storage) where Storage: AppStorage {
@@ -65,7 +83,8 @@ public struct Window: MacSceneElement {
             .addObserver(forName: NSWindow.willCloseNotification, object: window, queue: nil) { _ in
                 storage.destroy = true
             }
-        let content = content.storage(data: .init(sceneStorage: storage, appStorage: app), type: MacMainView.self)
+        let content = content(.init(window: window))
+            .storage(data: .init(sceneStorage: storage, appStorage: app), type: MacMainView.self)
         if let pointer = content.pointer as? NSView {
             window.contentView = pointer
         }
@@ -89,17 +108,17 @@ public struct Window: MacSceneElement {
         app: Storage,
         updateProperties: Bool
     ) where Storage: AppStorage {
+        guard let window = storage.pointer as? NSWindow else {
+            return
+        }
         if let content = storage.content[.mainContent]?.first {
-            self.content.updateStorage(
+            self.content(.init(window: window)).updateStorage(
                 content,
                 data: .init(sceneStorage: storage, appStorage: app),
                 updateProperties: updateProperties,
                 type: MacMainView.self
             )
         }
-        guard let window = storage.pointer as? NSWindow else {
-            return
-        }
         guard updateProperties else {
             return
         }
@@ -155,3 +174,6 @@ public struct Window: MacSceneElement {
     }
 
 }
+
+/// The window type.
+public typealias MacWindow = Window.MacWindow

Sources/Demo/Demo.swift

@@ -27,7 +27,7 @@ struct Demo: App {
     @State private var menuPresented = false
 
     var scene: Scene {
-        Window("Main", id: "main") {
+        Window("Main", id: "main") { _ in
             NavigationSplitView {
                 List(elements, selection: $selectedElement) { element in
                     Label(element.id, icon: .system(name: "play.fill"))