Add ForEach support (#588)

Author: Kyle-Ye

Example/HostingExample/ViewController.swift

@@ -66,6 +66,6 @@ class ViewController: NSViewController {
 
 struct ContentView: View {
     var body: some View {
-        MyViewThatFitsExample()
+        ForEachExample()
     }
 }

Example/OpenSwiftUIUITests/View/DynamicViewContent/ForEachUITests.swift

@@ -0,0 +1,40 @@
+//
+//  ForEachUITests.swift
+//  OpenSwiftUIUITests
+
+import Testing
+import SnapshotTesting
+
+@MainActor
+@Suite(.snapshots(record: .never, diffTool: diffTool))
+struct ForEachUITests {
+    @Test
+    func offset() {
+        struct ContentView: View {
+            var body: some View {
+                VStack(spacing: 0) {
+                    ForEach(0 ..< 6) { index in
+                        Color.red.opacity(Double(index) / 6.0 )
+                    }
+                }
+            }
+        }
+        openSwiftUIAssertSnapshot(of: ContentView())
+    }
+
+    @Test
+    func keyPath() {
+        struct ContentView: View {
+            let opacities = [0, 0.2, 0.4, 0.6, 0.8, 1.0]
+
+            var body: some View {
+                VStack(spacing: 0) {
+                    ForEach(opacities, id: \.self) { opacity in
+                        Color.red.opacity(opacity)
+                    }
+                }
+            }
+        }
+        openSwiftUIAssertSnapshot(of: ContentView())
+    }
+}

Example/SharedExample/View/DynamicContentView/ForEachExample.swift

@@ -0,0 +1,96 @@
+//
+//  ForEachExample.swift
+//  SharedExample
+
+#if OPENSWIFTUI
+import OpenObservation
+import OpenSwiftUI
+#else
+import Observation
+import SwiftUI
+#endif
+
+struct ForEachExample: View {
+    var body: some View {
+//        HStack {
+//            ForEachOffsetExample()
+//            ForEachKeyPathExample()
+//        }
+        ForEachDynamicView()
+    }
+}
+
+struct ForEachOffsetExample: View {
+    var body: some View {
+        VStack(spacing: 0) {
+            ForEach(0 ..< 6) { index in
+                Color.red.opacity(Double(index) / 6.0 )
+            }
+        }
+    }
+}
+
+struct ForEachKeyPathExample: View {
+    let opacities = [0, 0.2, 0.4, 0.6, 0.8, 1.0]
+
+    var body: some View {
+        VStack(spacing: 0) {
+            ForEach(opacities, id: \.self) { opacity in
+                Color.red.opacity(opacity)
+            }
+        }
+    }
+}
+
+// TODO: Animation test case
+struct ForEachDynamicView: View {
+    @State var opacities = [0, 0.5, 1.0]
+
+    var body: some View {
+        VStack(spacing: 0) {
+            ForEach(opacities, id: \.self) { opacity in
+                Color.red.opacity(opacity)
+            }
+        }.onAppear {
+            DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
+                withAnimation(.spring) {
+                    opacities.insert(0.25, at: 1)
+                    opacities.insert(0.75, at: 3)
+                }
+            }
+        }
+    }
+}
+
+struct ForEachNonConstantRangeView: View {
+    let range = 0..<5
+
+    var body: some View {
+        // Expect to emit warning: "Non-constant range: not an integer range" in compile time using Xcode toolchain
+        ForEach(range) { _ in
+            EmptyView()
+        }
+    }
+}
+
+@Observable
+private class ForEachLazyContainerNonConstantCountViewModel {
+    var data: [Int] = [1, 2]
+}
+
+// TODO: LazyContainer (eg. List / LazyHVStack)
+struct ForEachLazyContainerNonConstantCountView: View {
+    private typealias Model = ForEachLazyContainerNonConstantCountViewModel
+
+    @State private var model = Model()
+
+    var body: some View {
+//        List {
+            ForEach(model.data, id: \.self) { i in
+                if i % 2 == 0 {
+                    Text(i.description)
+                }
+            }
+//        }
+    }
+}

Sources/OpenSwiftUICore/Layout/LazyContainer/LazyContainer.swift

@@ -0,0 +1,34 @@
+//
+//  LazyContainer.swift
+//  OpenSwiftUICore
+//
+//  Audited for 6.5.4
+//  Status: Complete
+
+struct IsInLazyContainer: ViewInputBoolFlag  {}
+
+extension _GraphInputs {
+    @inline(__always)
+    package var isInLazyContainer: Bool {
+        get { self[IsInLazyContainer.self]  }
+        set { self[IsInLazyContainer.self] = newValue }
+    }
+}
+
+extension _ViewInputs {
+    package mutating func coreConfigureForLazyContainer() {
+        isInLazyContainer = true
+    }
+
+    package var isInLazyContainer: Bool {
+        get { base.isInLazyContainer }
+        set { base.isInLazyContainer = newValue }
+    }
+}
+
+extension _ViewListInputs {
+    package var isInLazyContainer: Bool {
+        get { base.isInLazyContainer }
+        set { base.isInLazyContainer = newValue }
+    }
+}

Sources/OpenSwiftUICore/Semantic/Feature.swift

@@ -18,10 +18,13 @@ extension Feature {
 
 package protocol UserDefaultKeyedFeature: Feature {
     static var key: String { get }
+
     static var defaultFeatureValue: Bool { get }
+
     #if !os(WASI)
     static var defaults: UserDefaults { get }
     #endif
+
     static var cachedValue: Bool? { get set }
 }
 
@@ -47,6 +50,7 @@ extension UserDefaultKeyedFeature {
     }
 
     package static var defaultFeatureValue: Bool { false }
+
     #if !os(WASI)
     package static var defaults: UserDefaults { .standard }
     #endif

Sources/OpenSwiftUICore/Util/UserDefaultsAdditions.swift

@@ -0,0 +1,14 @@
+//
+//  UserDefaultsAdditions.swift
+//  OpenSwiftUICore
+//
+//  Audited for 6.5.4
+//  Status: Complete
+
+package import Foundation
+
+extension UserDefaults {
+    package static let uiKit = UserDefaults(suiteName: "com.apple.UIKit")
+
+    package static let openSwiftUI = UserDefaults(suiteName: "org.OpenSwiftUIProject.OpenSwiftUI")
+}

Sources/OpenSwiftUICore/View/AnyView.swift renamed to Sources/OpenSwiftUICore/View/DynamicView/AnyView.swift

@@ -2,12 +2,15 @@
 //  DynamicViewContent.swift
 //  OpenSwiftUICore
 //
-//  Audited for 6.0.87
+//  Audited for 6.5.4
 //  Status: Complete
 
+// MARK: - DynamicViewContent
+
 /// A type of view that generates views from an underlying collection of data.
 @available(OpenSwiftUI_v1_0, *)
 public protocol DynamicViewContent: View {
+
     /// The type of the underlying collection of data.
     associatedtype Data: Collection
 
@@ -23,6 +26,8 @@ extension ModifiedContent: DynamicViewContent where Content: DynamicViewContent,
     }
 }
 
+// MARK: - DynamicViewContent Traits
+
 package struct DynamicViewContentIDTraitKey: _ViewTraitKey {
     package static let defaultValue: Int? = nil
 }