Add DynamicViewContent (#211)

Author: Kyle-Ye

Sources/OpenSwiftUICore/View/DynamicViewContent.swift

@@ -0,0 +1,40 @@
+//
+//  DynamicViewContent.swift
+//  OpenSwiftUICore
+//
+//  Audited for iOS 18.0
+//  Status: Complete
+
+/// A type of view that generates views from an underlying collection of data.
+public protocol DynamicViewContent: View {
+    /// The type of the underlying collection of data.
+    associatedtype Data: Collection
+
+    /// The collection of underlying data.
+    var data: Data { get }
+}
+
+extension ForEach: DynamicViewContent where Content: View {}
+
+extension ModifiedContent: DynamicViewContent where Content: DynamicViewContent, Modifier: ViewModifier {
+    public var data: Content.Data {
+        content.data
+    }
+}
+
+package struct DynamicViewContentIDTraitKey: _ViewTraitKey {
+    package static let defaultValue: Int? = nil
+}
+
+package struct DynamicViewContentOffsetTraitKey: _ViewTraitKey {
+    package static let defaultValue: Int? = nil
+}
+
+package struct DynamicContentOffsetVisitor: ViewListVisitor {
+    package var offset: Int?
+
+    package mutating func visit(view: _ViewList_View, traits: ViewTraitCollection) -> Bool {
+        offset = traits.value(for: DynamicViewContentOffsetTraitKey.self)
+        return false
+    }
+}

Sources/OpenSwiftUICore/View/Variadic/ForEach.swift renamed to Sources/OpenSwiftUICore/View/ForEach.swift

@@ -44,11 +44,23 @@
 /// ![A vertically arranged stack of labels showing various standard fonts,
 /// such as Large Title and Headline.](OpenSwiftUI-ForEach-fonts.png)
 public struct ForEach<Data, ID, Content> where Data: RandomAccessCollection, ID: Hashable {
-
     /// The collection of underlying identified data that OpenSwiftUI uses to create
     /// views dynamically.
     public var data: Data
 
     /// A function to create content on demand using the underlying data.
     public var content: (Data.Element) -> Content
 }
+
+@available(*, unavailable)
+extension ForEach: Sendable {}
+
+extension ForEach: View, PrimitiveView where Content: View {
+    nonisolated public static func _makeView(view: _GraphValue<Self>, inputs: _ViewInputs) -> _ViewOutputs {
+        preconditionFailure("TODO")
+    }
+
+    nonisolated public static func _makeViewList(view: _GraphValue<ForEach<Data, ID, Content>>, inputs: _ViewListInputs) -> _ViewListOutputs {
+        preconditionFailure("TODO")
+    }
+}