Update VariadicView (#95)

* Update VariadicView

* Update HVStackLayout documentation

* Update VariadicView

Sources/OpenSwiftUI/Core/View/ConditionalContent.swift

@@ -30,9 +30,9 @@ extension _ConditionalContent: View, PrimitiveView where TrueContent: View, Fals
 
     public static func _makeView(view: _GraphValue<Self>, inputs: _ViewInputs) -> _ViewOutputs {
         if _SemanticFeature_v2.isEnable {
-            return makeImplicitRoot(view: view, inputs: inputs)
+            makeImplicitRoot(view: view, inputs: inputs)
         } else {
-            return AnyView._makeView(
+            AnyView._makeView(
                 view: _GraphValue(ChildView(content: view.value)),
                 inputs: inputs
             )

Sources/OpenSwiftUI/Core/View/VariadicView/ForEach.swift

@@ -0,0 +1,54 @@
+//
+//  ForEach.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: WIP
+
+/// A structure that computes views on demand from an underlying collection of
+/// identified data.
+///
+/// Use `ForEach` to provide views based on a
+/// [RandomAccessCollection](https://developer.apple.com/documentation/swift/randomaccesscollection)
+/// of some data type. Either the collection's elements must conform to
+/// [Identifiable](https://developer.apple.com/documentation/swift/identifiable) or you
+/// need to provide an `id` parameter to the `ForEach` initializer.
+///
+/// The following example creates a `NamedFont` type that conforms to
+/// [Identifiable](https://developer.apple.com/documentation/swift/identifiable), and an
+/// array of this type called `namedFonts`. A `ForEach` instance iterates
+/// over the array, producing new ``Text`` instances that display examples
+/// of each OpenSwiftUI ``Font`` style provided in the array.
+///
+///     private struct NamedFont: Identifiable {
+///         let name: String
+///         let font: Font
+///         var id: String { name }
+///     }
+///
+///     private let namedFonts: [NamedFont] = [
+///         NamedFont(name: "Large Title", font: .largeTitle),
+///         NamedFont(name: "Title", font: .title),
+///         NamedFont(name: "Headline", font: .headline),
+///         NamedFont(name: "Body", font: .body),
+///         NamedFont(name: "Caption", font: .caption)
+///     ]
+///
+///     var body: some View {
+///         ForEach(namedFonts) { namedFont in
+///             Text(namedFont.name)
+///                 .font(namedFont.font)
+///         }
+///     }
+///
+/// ![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
+}

Sources/OpenSwiftUI/Core/View/VariadicView/VariadicView.swift

@@ -0,0 +1,49 @@
+/// A type of structured content that is passed as an argument to a
+/// `Root`'s result builder, creating a `Tree` that conditionally conforms
+/// to protocols like `View`.
+///
+/// For example, `View`s  can be passed to a `Layout` result builder
+/// creating a `View`:
+///
+///     HStack {
+///         Image(name: "envelope")
+///         Text("Your time away request has been approved")
+///         Spacer()
+///         Text(timestamp, format: .dateTime).layoutPriority(1)
+///     }
+///     
+public enum _VariadicView {
+    public typealias Root = _VariadicView_Root
+    public typealias ViewRoot = _VariadicView_ViewRoot
+    public typealias Children = _VariadicView_Children
+//    public typealias UnaryViewRoot = _VariadicView_UnaryViewRoot
+//    public typealias MultiViewRoot = _VariadicView_MultiViewRoot
+
+    @frozen
+    public struct Tree<Root: _VariadicView_Root, Content> {
+        public var root: Root
+        public var content: Content
+        @inlinable
+        init(root: Root, content: Content) {
+            self.root = root
+            self.content = content
+        }
+
+        @inlinable public init(_ root: Root, @ViewBuilder content: () -> Content) {
+            self.root = root
+            self.content = content()
+        }
+    }
+}
+
+extension _VariadicView_ViewRoot {
+    func bodyError() -> Never {
+        fatalError("body() should not be called on \(Self.self)")
+    }
+}
+
+extension _VariadicView_ViewRoot where Body == Never {
+    public func body(children: _VariadicView.Children) -> Never {
+        bodyError()
+    }
+}

Sources/OpenSwiftUI/Core/View/VariadicView/VariadicView_Children.swift

@@ -0,0 +1,69 @@
+//
+//  VariadicView_Children.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: TODO
+//  ID: 52A2FFECFBCF37BFFEED558E33EBD1E3
+
+internal import OpenGraphShims
+
+/// An ad hoc collection of the children of a variadic view.
+public struct _VariadicView_Children {
+    var list: ViewList
+    var contentSubgraph: OGSubgraph
+}
+
+extension _VariadicView_Children: RandomAccessCollection {
+    public struct Element: PrimitiveView, UnaryView, Identifiable {
+
+//        var view: _ViewList_View
+        var traits: ViewTraitCollection
+
+        public var id: AnyHashable {
+//            view.viewID
+            fatalError("TODO")
+
+        }
+        public func id<ID>(as _: ID.Type = ID.self) -> ID? where ID : Hashable {
+            fatalError("TODO")
+        }
+
+        public subscript<Trait: _ViewTraitKey>(key: Trait.Type) -> Trait.Value {
+            get { traits[key] }
+            set { traits[key] = newValue }
+        }
+
+        public static func _makeView(view: _GraphValue<_VariadicView_Children.Element>, inputs: _ViewInputs) -> _ViewOutputs {
+            fatalError("TODO")
+        }
+    }
+
+    public var startIndex: Int {
+        fatalError("TODO")
+
+//      get
+    }
+    public var endIndex: Int {
+        fatalError("TODO")
+
+//      get
+    }
+    public subscript(index: Int) -> _VariadicView_Children.Element {
+        fatalError("TODO")
+
+//      get
+    }
+}
+
+extension _VariadicView_Children {
+    private struct Child: Rule, AsyncAttribute {
+        typealias Value = ForEach<_VariadicView_Children, AnyHashable, _VariadicView_Children.Element>
+
+        @Attribute var children: _VariadicView_Children
+
+        var value: Value {
+            fatalError("TODO")
+        }
+    }
+}

Sources/OpenSwiftUI/Core/View/VariadicView/VariadicView_ImplicitRoot.swift

@@ -0,0 +1,24 @@
+//
+//  VariadicView_ImplicitRoot.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: Complete
+
+package protocol _VariadicView_AnyImplicitRoot {
+    static func visitType<V>(visitor: inout V) where V: _VariadicView_ImplicitRootVisitor
+}
+
+package protocol _VariadicView_ImplicitRootVisitor {
+    mutating func visit<R>(type: R.Type) where R: _VariadicView_ImplicitRoot
+}
+
+package protocol _VariadicView_ImplicitRoot: _VariadicView_AnyImplicitRoot, _VariadicView_ViewRoot {
+    static var implicitRoot: Self { get }
+}
+
+extension _VariadicView_ImplicitRoot {
+    package func visitType<Visitor: _VariadicView_ImplicitRootVisitor>(visitor: inout Visitor) {
+        visitor.visit(type: Self.self)
+    }
+}

Sources/OpenSwiftUI/Core/View/VariadicView/VariadicView_Root.swift

@@ -0,0 +1,30 @@
+//
+//  VariadicView_ImplicitRoot.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: Complete
+
+/// A type that creates a `Tree`, managing content subtrees passed to a result builder.
+///
+/// - SeeAlso: _VariadicView.Root.
+public protocol _VariadicView_Root {
+    static var _viewListOptions: Int { get }
+}
+
+extension _VariadicView_Root {
+    public static var _viewListOptions: Int {
+        0
+    }
+
+    package static var viewListOptions: _ViewListInputs.Options {
+        .init(rawValue: _viewListOptions)
+    }
+
+    public static func _viewListCount(
+        inputs _: _ViewListCountInputs,
+        body _: (_ViewListCountInputs) -> Int?
+    ) -> Int? {
+        nil
+    }
+}

Sources/OpenSwiftUI/Core/View/VariadicView/VariadicView_ViewRoot.swift

@@ -0,0 +1,83 @@
+//
+//  VariadicView_ImplicitRoot.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: WIP
+//  ID: 00F12C0E37A19C593ECA0DBD3BE26541
+
+internal import OpenGraphShims
+
+/// A type of root that creates a `View` when its result builder is invoked with
+///  `View`.
+/// - SeeAlso: _VariadicView.ViewRoot.
+/// - Note: Requirements mirror `View`'s.
+public protocol _VariadicView_ViewRoot: _VariadicView_Root {
+    associatedtype Body: View
+
+    static func _makeView(
+        root: _GraphValue<Self>,
+        inputs: _ViewInputs,
+        body: (_Graph, _ViewInputs) -> _ViewListOutputs
+    ) -> _ViewOutputs
+
+    static func _makeViewList(
+        root: _GraphValue<Self>,
+        inputs: _ViewListInputs,
+        body: @escaping (_Graph, _ViewListInputs) -> _ViewListOutputs
+    ) -> _ViewListOutputs
+
+    static func _viewListCount(
+        inputs: _ViewListCountInputs,
+        body: (_ViewListCountInputs) -> Int?
+    ) -> Int?
+
+    @ViewBuilder
+    func body(children: _VariadicView.Children) -> Body
+}
+
+extension _VariadicView_ViewRoot {
+    public static func _makeView(
+        root: _GraphValue<Self>,
+        inputs: _ViewInputs,
+        body: (_Graph, _ViewInputs) -> _ViewListOutputs
+    ) -> _ViewOutputs {
+        fatalError("TODO")
+    }
+
+    public static func _makeViewList(
+        root: _GraphValue<Self>,
+        inputs: _ViewListInputs,
+        body: @escaping (_Graph, _ViewListInputs) -> _ViewListOutputs
+    ) -> _ViewListOutputs {
+        fatalError("TODO")
+    }
+
+    public static func _viewListCount(inputs: _ViewListCountInputs) -> Int? {
+        Body._viewListCount(inputs: inputs)
+    }
+}
+
+
+// MARK: - ViewRootBody
+
+private struct ViewRootBody<Root> {
+    @Attribute var root: Root
+    @Attribute var list: ViewList
+    let contentSubgraph: OGSubgraph
+}
+
+extension _ViewInputs {
+    private struct ImplicitRootType: ViewInput {
+        static let defaultValue: _VariadicView_AnyImplicitRoot.Type = _VStackLayout.self
+    }
+}
+
+extension View {
+    static func makeImplicitRoot(view: _GraphValue<Self>, inputs: _ViewInputs) -> _ViewOutputs {
+        // TODO
+        return .init()
+    }
+}
+
+// TODO: ViewModifier

Sources/OpenSwiftUI/Core/View/ViewList/ViewListCountInputs.swift

@@ -7,9 +7,9 @@
 
 /// Input values to `View._viewListCount()`.
 public struct _ViewListCountInputs {
-    var customInputs : PropertyList
-    var options : _ViewListInputs.Options
-    var baseOptions : _GraphInputs.Options
+    var customInputs: PropertyList
+    var options: _ViewListInputs.Options
+    var baseOptions: _GraphInputs.Options
 
     subscript<Input: GraphInput>(_ type: Input.Type) -> Input.Value {
         get { customInputs[type] }

Sources/OpenSwiftUI/Core/View/ViewList/ViewListInputs.swift

@@ -12,12 +12,15 @@ public struct _ViewListInputs {
     private var base: _GraphInputs
     var implicitID: Int
     var options: _ViewListInputs.Options
-    @OptionalAttribute
-    var traits: ViewTraitCollection?
+    @OptionalAttribute var traits: ViewTraitCollection?
     var traitKeys: ViewTraitKeys?
 
-    struct Options: OptionSet {
-        let rawValue: Int
+    package struct Options: OptionSet {
+        package init(rawValue: Int) {
+            self.rawValue = rawValue
+        }
+
+        package let rawValue: Int
     }
 
     // MARK: - base

Sources/OpenSwiftUI/Core/View/ViewList/ViewList_ID.swift

@@ -0,0 +1,12 @@
+//  ID: 70E71091E926A1B09B75AAEB38F5AA3F
+
+struct _ViewList_ID {
+    var _index: Int32
+    var implicitID: Int32
+    private var explicitIDs: [Explicit]
+}
+
+extension _ViewList_ID {
+    private struct Explicit {
+    }
+}

Sources/OpenSwiftUI/Core/View/ViewList/ViewList_View.swift

@@ -0,0 +1,9 @@
+internal import OpenGraphShims
+
+struct _ViewList_View {
+    var elements: _ViewList_Elements
+    var id: _ViewList_ID
+    var index: Int
+    var count: Int
+    var contentSubgraph: OGSubgraph
+}

Sources/OpenSwiftUI/Core/View/ViewRoot.swift

@@ -6,9 +6,3 @@
 //  Status: WIP
 //  ID: 00F12C0E37A19C593ECA0DBD3BE26541
 
-extension View {
-    static func makeImplicitRoot(view: _GraphValue<Self>, inputs: _ViewInputs) -> _ViewOutputs {
-        // TODO
-        return .init()
-    }
-}