Fix build issue with SwiftWasm 5.7

.github/ISSUE_TEMPLATE/bug_report.md

@@ -3,7 +3,7 @@ name: Bug report
 about: Create a report to help us improve
 title: ''
 labels: bug
-assignees: carson-katri
+assignees: MaxDesiatov
 
 ---
 
@@ -28,17 +28,17 @@ A clear and concise description of what you expected to happen.
 If this is a layout/rendering issue, please provide screenshots for both Tokamak and SwiftUI that highlight the difference.
 
 **Desktop (please complete the following information):**
- - OS: [e.g. macOS 12.4]
+ - OS: [e.g. macOS]
  - Browser [e.g. chrome, safari]
  - Version of the browser [e.g. 22]
- - Version of Tokamak [e.g. 0.10.1]
+ - Version of Tokamak [e.g. 0.6.1]
 
 **Smartphone (please complete the following information):**
- - Device: [e.g. iPhone 6]
+ - Device: [e.g. iPhone6]
- - OS: [e.g. iOS15.1]
+ - OS: [e.g. iOS8.1]
  - Browser [e.g. stock browser, safari]
  - Version of the browser [e.g. 22]
- - Version of Tokamak [e.g. 0.10.1]
+ - Version of Tokamak [e.g. 0.6.1]
 
 **Additional context**
 Add any other context about the problem here.

.github/workflows/ci.yml

@@ -14,88 +14,76 @@ jobs:
       - uses: swiftwasm/swiftwasm-action@v5.6
         with:
           shell-action: carton bundle --product TokamakDemo
-      - name: Check binary size
-        shell: bash
-        run: |
-          ls -la Bundle
-          ls -lh Bundle/*.wasm | awk '{printf  "::warning file=Sources/TokamakDemo/main.swift,line=1,col=1::TokamakDemo Wasm is %s.",$5}'
 
-  swiftwasm_test:
+  swiftwasm_test_5_6:
     runs-on: ubuntu-20.04
-    strategy:
-      fail-fast: true
-      matrix:
-        include:
-          - { toolchain: wasm-5.6.0-RELEASE }
-          - { toolchain: wasm-5.7-SNAPSHOT-2022-07-27-a }
-          - { toolchain: wasm-DEVELOPMENT-SNAPSHOT-2022-07-23-a }
 
     steps:
       - uses: actions/checkout@v2
-      - run: echo "${{ matrix.toolchain }}" > .swift-version
       - uses: swiftwasm/swiftwasm-action@v5.6
         with:
-          shell-action: carton test --environment node
+          shell-action: carton test
 
-  core_macos_build:
+  # Disabled until macos-12 is available on GitHub Actions, which is required for Xcode 13.3
-    runs-on: macos-12
+  # core_macos_build:
+  #   runs-on: macos-11
 
-    steps:
+  #   steps:
-      - uses: actions/checkout@v2
+  #     - uses: actions/checkout@v2
-      - name: Run the test suite on macOS, build the demo project for iOS
+  #     - name: Run the test suite on macOS, build the demo project for iOS
-        shell: bash
+  #       shell: bash
-        run: |
+  #       run: |
-          set -ex
+  #         set -ex
-          sudo xcode-select --switch /Applications/Xcode_13.4.app/Contents/Developer/
+  #         sudo xcode-select --switch /Applications/Xcode_13.0.app/Contents/Developer/
-          # avoid building unrelated products for testing by specifying the test product explicitly
+  #         # avoid building unrelated products for testing by specifying the test product explicitly
-          swift build --product TokamakPackageTests
+  #         swift build --product TokamakPackageTests
-          `xcrun --find xctest` .build/debug/TokamakPackageTests.xctest ||
+  #         `xcrun --find xctest` .build/debug/TokamakPackageTests.xctest ||
-            (cp -r /var/folders/*/*/*/*Tests . ; exit 1)
+  #           (cp -r /var/folders/*/*/*/*Tests . ; exit 1)
 
-          rm -rf Sources/TokamakGTKCHelpers/*.c
+  #         rm -rf Sources/TokamakGTKCHelpers/*.c
 
-          xcodebuild -version
+  #         xcodebuild -version
 
-          # Make sure Tokamak can be built on macOS so that Xcode autocomplete works.
+  #         # Make sure Tokamak can be built on macOS so that Xcode autocomplete works.
-          xcodebuild -scheme TokamakDemo -destination 'generic/platform=macOS' \
+  #         # Disable macOS builds until Monterey is available on GHA.
-            CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO CODE_SIGNING_ALLOWED=NO | \
+  #         # xcodebuild -scheme TokamakDemo -destination 'generic/platform=macOS' \
-            xcpretty --color
+  #         #   CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO CODE_SIGNING_ALLOWED=NO | \
+  #         #   xcpretty --color
 
-          cd "NativeDemo"
+  #         cd "NativeDemo"
-          xcodebuild -scheme iOS -destination 'generic/platform=iOS' \
+  #         xcodebuild -scheme iOS -destination 'generic/platform=iOS' \
-            CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO CODE_SIGNING_ALLOWED=NO | \
+  #           CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO CODE_SIGNING_ALLOWED=NO | \
-            xcpretty --color
+  #           xcpretty --color
-          cd ..
+  #         cd ..
 
-          ./benchmark.sh
+  #         ./benchmark.sh
 
-      - name: Upload failed snapshots
+  #     - name: Upload failed snapshots
-        uses: actions/upload-artifact@v2
+  #       uses: actions/upload-artifact@v2
-        if: ${{ failure() }}
+  #       if: ${{ failure() }}
-        with:
+  #       with:
-          name: Failed snapshots
+  #         name: Failed snapshots
-          path: '*Tests'
+  #         path: '*Tests'
 
-# FIXME: disabled due to build errors, to be investigated
+  # gtk_macos_build:
-#   gtk_macos_build:
+  #   runs-on: macos-11
-#     runs-on: macos-12
+
-#
+  #   steps:
-#     steps:
+  #     - uses: actions/checkout@v2
-#       - uses: actions/checkout@v2
+  #     - name: Build the GTK renderer on macOS
-#       - name: Build the GTK renderer on macOS
+  #       shell: bash
-#         shell: bash
+  #       run: |
-#         run: |
+  #         set -ex
-#           set -ex
+  #         sudo xcode-select --switch /Applications/Xcode_13.0.app/Contents/Developer/
-#           sudo xcode-select --switch /Applications/Xcode_13.4.1.app/Contents/Developer/
+
-#
+  #         brew install gtk+3
-#           brew install gtk+3
+
-#
+  #         make build
-#           make build
 
   gtk_ubuntu_18_04_build:
     runs-on: ubuntu-latest
     container:
-      image: swiftlang/swift:nightly-5.7-bionic
+      image: swiftlang/swift:nightly-bionic
 
     steps:
       - uses: actions/checkout@v2
@@ -110,7 +98,7 @@ jobs:
   gtk_ubuntu_20_04_build:
     runs-on: ubuntu-latest
     container:
-      image: swiftlang/swift:nightly-5.7-focal
+      image: swiftlang/swift:nightly-focal
 
     steps:
       - uses: actions/checkout@v2

.github/workflows/codecov.yml

@@ -8,7 +8,7 @@ on:
 jobs:
   codecov:
     container:
-      image: swiftlang/swift:nightly-5.7-focal
+      image: swiftlang/swift:nightly-focal
     runs-on: ubuntu-latest
     steps:
     - run: apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y gtk+-3.0 libgtk+-3.0

.github/workflows/label.yml

@@ -24,7 +24,6 @@ jobs:
           dependencies,
           documentation,
           enhancement,
-          Fiber,
           refactor,
           SwiftUI compatibility,
           test suite,

.swiftformat

@@ -8,7 +8,5 @@
 --maxwidth 100
 --wraparguments before-first
 --funcattributes prev-line
---typeattributes prev-line
---varattributes prev-line
 --disable andOperator
---swiftversion 5.6
+--swiftversion 5.4

CONTRIBUTING.md

@@ -29,19 +29,6 @@ only `TokamakStaticHTML`, single-page apps would use `TokamakDOM`, maybe in conj
 Android at some point, probably in a separate `TokamakAndroid` module, Android apps would use
 `TokamakAndroid` with no need to be aware of any of the web modules.
 
-### Testing
-
-Tokamak uses [SnapshotTesting](https://github.com/pointfreeco/swift-snapshot-testing) library to
-make sure that HTML and layout generated by renderers stay consistent. To run the test suite on macOS
-you should use this command:
-
-```sh
-swift build --product TokamakPackageTests && `xcrun --find xctest` .build/debug/TokamakPackageTests.xctest
-```
-
-Unfortunately, plain `swift test` won't work as it tries to build targets that aren't related to
-the test suite.
-
 ### Coding Style
 
 This project uses [SwiftFormat](https://github.com/nicklockwood/SwiftFormat) and

Package.swift

@@ -46,23 +46,23 @@ let package = Package(
   ],
   dependencies: [
     .package(
-      url: "https://gitlink.org.cn/dnrops/JavaScriptKit.git",
+      url: "https://github.com/swiftwasm/JavaScriptKit.git",
       from: "0.15.0"
     ),
     .package(
-      url: "https://gitlink.org.cn/dnrops/OpenCombine.git",
+      url: "https://github.com/OpenCombine/OpenCombine.git",
       from: "0.12.0"
     ),
     .package(
-      url: "https://gitcode.net/dnrops/OpenCombineJS.git",
+      url: "https://github.com/swiftwasm/OpenCombineJS.git",
       from: "0.2.0"
     ),
     .package(
-      url: "https://gitlink.org.cn/dnrops/swift-benchmark",
+      url: "https://github.com/google/swift-benchmark",
       from: "0.1.2"
     ),
     .package(
-      url: "https://gitlink.org.cn/dnrops/swift-snapshot-testing.git",
+      url: "https://github.com/pointfreeco/swift-snapshot-testing.git",
       from: "1.9.0"
     ),
   ],
@@ -135,7 +135,6 @@ let package = Package(
       dependencies: [
         .product(name: "Benchmark", package: "swift-benchmark"),
         "TokamakCore",
-        "TokamakTestRenderer",
       ]
     ),
     .executableTarget(
@@ -195,25 +194,6 @@ let package = Package(
       name: "TokamakTestRenderer",
       dependencies: ["TokamakCore"]
     ),
-    .testTarget(
-      name: "TokamakLayoutTests",
-      dependencies: [
-        "TokamakCore",
-        "TokamakStaticHTML",
-        .product(
-          name: "SnapshotTesting",
-          package: "swift-snapshot-testing",
-          condition: .when(platforms: [.macOS])
-        ),
-      ]
-    ),
-    .testTarget(
-      name: "TokamakReconcilerTests",
-      dependencies: [
-        "TokamakCore",
-        "TokamakTestRenderer",
-      ]
-    ),
     .testTarget(
       name: "TokamakTests",
       dependencies: ["TokamakTestRenderer"]

README.md

@@ -138,31 +138,6 @@ This way both [Semantic UI](https://semantic-ui.com/) styles and [moment.js](htt
 localized date formatting (or any arbitrary style/script/font added that way) are available in your
 app.
 
-### Fiber renderers
-
-A new reconciler modeled after React's [Fiber reconciler](https://reactjs.org/docs/faq-internals.html#what-is-react-fiber)
-is optionally available. It can provide faster updates and allow for larger View hierarchies.
-It also includes layout steps that can match SwiftUI layouts closer than CSS approximations.
-
-You can specify which reconciler to use in your `App`'s configuration:
-
-```swift
-struct CounterApp: App {
-  static let _configuration: _AppConfiguration = .init(
-    // Specify `useDynamicLayout` to enable the layout steps in place of CSS approximations.
-    reconciler: .fiber(useDynamicLayout: true)
-  )
-
-  var body: some Scene {
-    WindowGroup("Counter Demo") {
-      Counter(count: 5, limit: 15)
-    }
-  }
-}
-```
-
-> *Note*: Not all `View`s and `ViewModifier`s are supported by Fiber renderers yet.
-
 ## Requirements
 
 ### For app developers
@@ -172,7 +147,7 @@ struct CounterApp: App {
   and macOS at the same time.
 - [Swift 5.6 or later](https://swift.org/download/) and Ubuntu 18.04/20.04 if you'd like to use Linux.
   Other Linux distributions are currently not supported.
-- [`carton` 0.15.x](https://carton.dev) (carton is our build tool, see the ["Getting started" section](#getting-started) for installation steps)
+- [`carton` 0.14.x](https://carton.dev) (carton is our build tool, see the ["Getting started" section](#getting-started) for installation steps)
 
 ### For users of apps depending on Tokamak
 
@@ -241,9 +216,6 @@ carton dev
 You can also clone this repository and run `carton dev --product TokamakDemo` in its root
 directory. This will build the demo app that shows almost all of the currently implemented APIs.
 
-If you have any questions, pleaes check out the [FAQ](docs/FAQ.md) document, and/or join the
-#tokamak channel on [the SwiftWasm Discord server](https://discord.gg/ashJW8T8yp).
-
 ## Security
 
 By default, the DOM renderer will escape HTML control characters in `Text` views. If you wish
@@ -325,10 +297,9 @@ appreciated and helps in maintaining the project.
 ## Maintainers
 
 In alphabetical order: [Carson Katri](https://github.com/carson-katri),
-[Ezra Berch](https://github.com/ezraberch),
+[David Hunt](https://github.com/foscomputerservices), [Ezra Berch](https://github.com/ezraberch),
-[Jed Fox](https://jedfox.com),
+[Jed Fox](https://jedfox.com), [Max Desiatov](https://desiatov.com),
-[Morten Bek Ditlevsen](https://github.com/mortenbekditlevsen/),
+[Morten Bek Ditlevsen](https://github.com/mortenbekditlevsen/), [Yuta Saito](https://github.com/kateinoigakukun/).
-[Yuta Saito](https://github.com/kateinoigakukun/).
 
 ## Acknowledgments
 

Sources/TokamakCore/Animation/Animatable.swift

@@ -40,20 +40,14 @@ public extension Animatable where Self.AnimatableData == EmptyAnimatableData {
   }
 }
 
-@frozen
+@frozen public struct EmptyAnimatableData: VectorArithmetic {
-public struct EmptyAnimatableData: VectorArithmetic {
   @inlinable
   public init() {}
-
+  @inlinable public static var zero: Self { .init() }
-  @inlinable
-  public static var zero: Self { .init() }
-
   @inlinable
   public static func += (lhs: inout Self, rhs: Self) {}
-
   @inlinable
   public static func -= (lhs: inout Self, rhs: Self) {}
-
   @inlinable
   public static func + (lhs: Self, rhs: Self) -> Self {
     .zero
@@ -66,15 +60,11 @@ public struct EmptyAnimatableData: VectorArithmetic {
 
   @inlinable
   public mutating func scale(by rhs: Double) {}
-
+  @inlinable public var magnitudeSquared: Double { .zero }
-  @inlinable
-  public var magnitudeSquared: Double { .zero }
-
   public static func == (a: Self, b: Self) -> Bool { true }
 }
 
-@frozen
+@frozen public struct AnimatablePair<First, Second>: VectorArithmetic
-public struct AnimatablePair<First, Second>: VectorArithmetic
   where First: VectorArithmetic, Second: VectorArithmetic
 {
   public var first: First
@@ -91,8 +81,7 @@ public struct AnimatablePair<First, Second>: VectorArithmetic
     set { (first, second) = newValue }
   }
 
-  @_transparent
+  @_transparent public static var zero: Self {
-  public static var zero: Self {
     @_transparent get {
       .init(First.zero, Second.zero)
     }
@@ -126,8 +115,7 @@ public struct AnimatablePair<First, Second>: VectorArithmetic
     second.scale(by: rhs)
   }
 
-  @_transparent
+  @_transparent public var magnitudeSquared: Double {
-  public var magnitudeSquared: Double {
     @_transparent get {
       first.magnitudeSquared + second.magnitudeSquared
     }

Sources/TokamakCore/Animation/Animation.swift

@@ -139,8 +139,7 @@ public struct _AnimationProxy {
   public func resolve() -> _AnimationBoxBase._Resolved { subject.box.resolve() }
 }
 
-@frozen
+@frozen public struct _AnimationModifier<Value>: ViewModifier, Equatable
-public struct _AnimationModifier<Value>: ViewModifier, Equatable
   where Value: Equatable
 {
   public var animation: Animation?
@@ -156,9 +155,7 @@ public struct _AnimationModifier<Value>: ViewModifier, Equatable
     let content: Content
     let animation: Animation?
     let value: Value
-
+    @State private var lastValue: Value?
-    @State
-    private var lastValue: Value?
 
     var body: some View {
       content.transaction {
@@ -183,8 +180,7 @@ public struct _AnimationModifier<Value>: ViewModifier, Equatable
   }
 }
 
-@frozen
+@frozen public struct _AnimationView<Content>: View
-public struct _AnimationView<Content>: View
   where Content: Equatable, Content: View
 {
   public var content: Content

Sources/TokamakCore/Animation/Transaction.swift

@@ -13,7 +13,7 @@
 // limitations under the License.
 
 public struct Transaction {
-  /// The overridden transaction for a state change in a `withTransaction` block.
+  /// The overriden transaction for a state change in a `withTransaction` block.
   /// Is always set back to `nil` when the block exits.
   static var _active: Self?
 
@@ -50,8 +50,7 @@ protocol _TransactionModifierProtocol {
   func modifyTransaction(_ transaction: inout Transaction)
 }
 
-@frozen
+@frozen public struct _TransactionModifier: ViewModifier {
-public struct _TransactionModifier: ViewModifier {
   public var transform: (inout Transaction) -> ()
 
   @inlinable
@@ -78,8 +77,7 @@ extension ModifiedContent: _TransactionModifierProtocol
   }
 }
 
-@frozen
+@frozen public struct _PushPopTransactionModifier<V>: ViewModifier where V: ViewModifier {
-public struct _PushPopTransactionModifier<V>: ViewModifier where V: ViewModifier {
   public var content: V
   public var base: _TransactionModifier
 

Sources/TokamakCore/Animation/VectorArithmetic.swift

@@ -25,9 +25,7 @@ public protocol VectorArithmetic: AdditiveArithmetic {
 extension Float: VectorArithmetic {
   @_transparent
   public mutating func scale(by rhs: Double) { self *= Float(rhs) }
-
+  @_transparent public var magnitudeSquared: Double {
-  @_transparent
-  public var magnitudeSquared: Double {
     @_transparent get { Double(self * self) }
   }
 }
@@ -35,9 +33,7 @@ extension Float: VectorArithmetic {
 extension Double: VectorArithmetic {
   @_transparent
   public mutating func scale(by rhs: Double) { self *= rhs }
-
+  @_transparent public var magnitudeSquared: Double {
-  @_transparent
-  public var magnitudeSquared: Double {
     @_transparent get { self * self }
   }
 }
@@ -45,9 +41,7 @@ extension Double: VectorArithmetic {
 extension CGFloat: VectorArithmetic {
   @_transparent
   public mutating func scale(by rhs: Double) { self *= CGFloat(rhs) }
-
+  @_transparent public var magnitudeSquared: Double {
-  @_transparent
-  public var magnitudeSquared: Double {
     @_transparent get { Double(self * self) }
   }
 }

Sources/TokamakCore/Animation/_AnimationSolvers.swift

@@ -21,7 +21,7 @@ import Foundation
 public protocol _AnimationSolver {
   /// Solve value at a specific point in time.
   func solve(at t: Double) -> Double
-  /// Calculates the duration of the animation to a specific precision.
+  /// Calculates the duration of the animation to a specific presision.
   func restingPoint(precision y: Double) -> Double
 }
 

Sources/TokamakCore/Animation/_AnyAnimatableData.swift

@@ -1,165 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-/// A type-eraser for `VectorArithmetic`.
-public struct _AnyAnimatableData: VectorArithmetic {
-  private var box: _AnyAnimatableDataBox?
-
-  private init(_ box: _AnyAnimatableDataBox?) {
-    self.box = box
-  }
-}
-
-/// A box for vector arithmetic types.
-///
-/// Conforming types are only expected to handle value types (enums and structs).
-/// Classes aren't really mutable so that scaling, but even then subclassing is impossible,
-/// at least in my attempts. Also `VectorArithmetic` does not have a self-conforming
-/// existential. Thus the problem of two types being equal but not sharing a common
-/// supertype is avoided. Consider a type `Super` that has subtypes `A : Super` and
-/// `B : Super`; casting both `A.self as? B.Type` and `B.self as? A.Type` fail.
-/// This is important for static operators, since non-type-erased operators get this right.
-/// Thankfully, only no-inheritance types are supported.
-private protocol _AnyAnimatableDataBox {
-  var value: Any { get }
-
-  func equals(_ other: Any) -> Bool
-
-  func add(_ other: Any) -> _AnyAnimatableDataBox
-  func subtract(_ other: Any) -> _AnyAnimatableDataBox
-
-  mutating func scale(by scalar: Double)
-  var magnitudeSquared: Double { get }
-}
-
-private struct _ConcreteAnyAnimatableDataBox<
-  Base: VectorArithmetic
->: _AnyAnimatableDataBox {
-  var base: Base
-
-  var value: Any {
-    base
-  }
-
-  // MARK: Equatable
-
-  func equals(_ other: Any) -> Bool {
-    guard let other = other as? Base else {
-      return false
-    }
-
-    return base == other
-  }
-
-  // MARK: AdditiveArithmetic
-
-  func add(_ other: Any) -> _AnyAnimatableDataBox {
-    guard let other = other as? Base else {
-      // TODO: Look into whether this should crash.
-      // SwiftUI didn't crash on the first beta.
-      return self
-    }
-
-    return Self(base: base + other)
-  }
-
-  func subtract(_ other: Any) -> _AnyAnimatableDataBox {
-    guard let other = other as? Base else {
-      // TODO: Look into whether this should crash.
-      // SwiftUI didn't crash on the first beta.
-      return self
-    }
-
-    return Self(base: base - other)
-  }
-
-  // MARK: VectorArithmetic
-
-  mutating func scale(by scalar: Double) {
-    base.scale(by: scalar)
-  }
-
-  var magnitudeSquared: Double {
-    base.magnitudeSquared
-  }
-}
-
-public extension _AnyAnimatableData {
-  // MARK: Equatable
-
-  static func == (lhs: Self, rhs: Self) -> Bool {
-    switch (rhs.box, lhs.box) {
-    case let (rhsBox?, lhsBox?):
-      return rhsBox.equals(lhsBox.value)
-
-    case (.some, nil), (nil, .some):
-      return false
-
-    case (nil, nil):
-      return true
-    }
-  }
-
-  // MARK: AdditiveArithmetic
-
-  static func + (lhs: Self, rhs: Self) -> Self {
-    switch (rhs.box, lhs.box) {
-    case let (rhsBox?, lhsBox?):
-      return Self(rhsBox.add(lhsBox.value))
-
-    case (let box?, nil), (nil, let box?):
-      return Self(box)
-
-    case (nil, nil):
-      return lhs
-    }
-  }
-
-  static func - (lhs: Self, rhs: Self) -> Self {
-    switch (rhs.box, lhs.box) {
-    case let (rhsBox?, lhsBox?):
-      return Self(rhsBox.subtract(lhsBox.value))
-
-    case (let box?, nil), (nil, let box?):
-      return Self(box)
-
-    case (nil, nil):
-      return lhs
-    }
-  }
-
-  static var zero: _AnyAnimatableData {
-    _AnyAnimatableData(nil)
-  }
-
-  // MARK: VectorArithmetic
-
-  mutating func scale(by rhs: Double) {
-    box?.scale(by: rhs)
-  }
-
-  var magnitudeSquared: Double {
-    box?.magnitudeSquared ?? 0
-  }
-}
-
-public extension _AnyAnimatableData {
-  init<Data: VectorArithmetic>(_ data: Data) {
-    box = _ConcreteAnyAnimatableDataBox(base: data)
-  }
-
-  var value: Any {
-    box?.value ?? ()
-  }
-}

Sources/TokamakCore/Animation/_VectorMath.swift

@@ -20,8 +20,7 @@ import Foundation
 public protocol _VectorMath: Animatable {}
 
 public extension _VectorMath {
-  @inlinable
+  @inlinable var magnitude: Double {
-  var magnitude: Double {
     animatableData.magnitudeSquared.squareRoot()
   }
 

Sources/TokamakCore/App/App.swift

@@ -28,10 +28,7 @@ public protocol App: _TitledApp {
   var body: Body { get }
 
   /// Implemented by the renderer to mount the `App`
-  static func _launch(
+  static func _launch(_ app: Self, _ rootEnvironment: EnvironmentValues)
-    _ app: Self,
-    with configuration: _AppConfiguration
-  )
 
   /// Implemented by the renderer to update the `App` on `ScenePhase` changes
   var _phasePublisher: AnyPublisher<ScenePhase, Never> { get }
@@ -39,38 +36,14 @@ public protocol App: _TitledApp {
   /// Implemented by the renderer to update the `App` on `ColorScheme` changes
   var _colorSchemePublisher: AnyPublisher<ColorScheme, Never> { get }
 
-  static var _configuration: _AppConfiguration { get }
-
   static func main()
 
   init()
 }
 
-public struct _AppConfiguration {
-  public let reconciler: Reconciler
-  public let rootEnvironment: EnvironmentValues
-
-  public init(
-    reconciler: Reconciler = .stack,
-    rootEnvironment: EnvironmentValues = .init()
-  ) {
-    self.reconciler = reconciler
-    self.rootEnvironment = rootEnvironment
-  }
-
-  public enum Reconciler {
-    /// Use the `StackReconciler`.
-    case stack
-    /// Use the `FiberReconciler` with layout steps optionally enabled.
-    case fiber(useDynamicLayout: Bool = false)
-  }
-}
-
 public extension App {
-  static var _configuration: _AppConfiguration { .init() }
-
   static func main() {
     let app = Self()
-    _launch(app, with: Self._configuration)
+    _launch(app, EnvironmentValues())
   }
 }

Sources/TokamakCore/App/AppStorage.swift

@@ -17,13 +17,9 @@
 
 import OpenCombineShim
 
-@propertyWrapper
+@propertyWrapper public struct AppStorage<Value>: DynamicProperty {
-public struct AppStorage<Value>: DynamicProperty {
   let provider: _StorageProvider?
-
+  @Environment(\._defaultAppStorage) var defaultProvider: _StorageProvider?
-  @Environment(\._defaultAppStorage)
-  var defaultProvider: _StorageProvider?
-
   var unwrappedProvider: _StorageProvider {
     provider ?? defaultProvider!
   }

Sources/TokamakCore/App/Scenes/Scene.swift

@@ -21,23 +21,8 @@ public protocol Scene {
   // FIXME: If I put `@SceneBuilder` in front of this
   // it fails to build with no useful error message.
   var body: Self.Body { get }
-
-  /// Override the default implementation for `Scene`s with body types of `Never`
-  /// or in cases where the body would normally need to be type erased.
-  ///
-  /// You can `visit(_:)` either another `Scene` or a `View` with a `SceneVisitor`
-  func _visitChildren<V: SceneVisitor>(_ visitor: V)
-
-  /// Create `SceneOutputs`, including any modifications to the environment, preferences, or a custom
-  /// `LayoutComputer` from the `SceneInputs`.
-  ///
-  /// > At the moment, `SceneInputs`/`SceneOutputs` are identical to `ViewInputs`/`ViewOutputs`.
-  static func _makeScene(_ inputs: SceneInputs<Self>) -> SceneOutputs
 }
 
-public typealias SceneInputs<S: Scene> = ViewInputs<S>
-public typealias SceneOutputs = ViewOutputs
-
 protocol TitledScene {
   var title: Text? { get }
 }

Sources/TokamakCore/App/Scenes/SceneBuilder.swift

@@ -29,14 +29,7 @@ public extension SceneBuilder {
   static func buildBlock<C0, C1>(_ c0: C0, _ c1: C1) -> some Scene where C0: Scene,
     C1: Scene
   {
-    _TupleScene(
+    _TupleScene((c0, c1), children: [_AnyScene(c0), _AnyScene(c1)])
-      (c0, c1),
-      children: [_AnyScene(c0), _AnyScene(c1)],
-      visit: {
-        $0.visit(c0)
-        $0.visit(c1)
-      }
-    )
   }
 }
 
@@ -44,15 +37,7 @@ public extension SceneBuilder {
   static func buildBlock<C0, C1, C2>(_ c0: C0, _ c1: C1, _ c2: C2) -> some Scene
     where C0: Scene, C1: Scene, C2: Scene
   {
-    _TupleScene(
+    _TupleScene((c0, c1, c2), children: [_AnyScene(c0), _AnyScene(c1), _AnyScene(c2)])
-      (c0, c1, c2),
-      children: [_AnyScene(c0), _AnyScene(c1), _AnyScene(c2)],
-      visit: {
-        $0.visit(c0)
-        $0.visit(c1)
-        $0.visit(c2)
-      }
-    )
   }
 }
 
@@ -65,13 +50,7 @@ public extension SceneBuilder {
   ) -> some Scene where C0: Scene, C1: Scene, C2: Scene, C3: Scene {
     _TupleScene(
       (c0, c1, c2, c3),
-      children: [_AnyScene(c0), _AnyScene(c1), _AnyScene(c2), _AnyScene(c3)],
+      children: [_AnyScene(c0), _AnyScene(c1), _AnyScene(c2), _AnyScene(c3)]
-      visit: {
-        $0.visit(c0)
-        $0.visit(c1)
-        $0.visit(c2)
-        $0.visit(c3)
-      }
     )
   }
 }
@@ -86,14 +65,7 @@ public extension SceneBuilder {
   ) -> some Scene where C0: Scene, C1: Scene, C2: Scene, C3: Scene, C4: Scene {
     _TupleScene(
       (c0, c1, c2, c3, c4),
-      children: [_AnyScene(c0), _AnyScene(c1), _AnyScene(c2), _AnyScene(c3), _AnyScene(c4)],
+      children: [_AnyScene(c0), _AnyScene(c1), _AnyScene(c2), _AnyScene(c3), _AnyScene(c4)]
-      visit: {
-        $0.visit(c0)
-        $0.visit(c1)
-        $0.visit(c2)
-        $0.visit(c3)
-        $0.visit(c4)
-      }
     )
   }
 }
@@ -118,15 +90,7 @@ public extension SceneBuilder {
         _AnyScene(c3),
         _AnyScene(c4),
         _AnyScene(c5),
-      ],
+      ]
-      visit: {
-        $0.visit(c0)
-        $0.visit(c1)
-        $0.visit(c2)
-        $0.visit(c3)
-        $0.visit(c4)
-        $0.visit(c5)
-      }
     )
   }
 }
@@ -153,16 +117,7 @@ public extension SceneBuilder {
         _AnyScene(c4),
         _AnyScene(c5),
         _AnyScene(c6),
-      ],
+      ]
-      visit: {
-        $0.visit(c0)
-        $0.visit(c1)
-        $0.visit(c2)
-        $0.visit(c3)
-        $0.visit(c4)
-        $0.visit(c5)
-        $0.visit(c6)
-      }
     )
   }
 }
@@ -191,17 +146,7 @@ public extension SceneBuilder {
         _AnyScene(c5),
         _AnyScene(c6),
         _AnyScene(c7),
-      ],
+      ]
-      visit: {
-        $0.visit(c0)
-        $0.visit(c1)
-        $0.visit(c2)
-        $0.visit(c3)
-        $0.visit(c4)
-        $0.visit(c5)
-        $0.visit(c6)
-        $0.visit(c7)
-      }
     )
   }
 }
@@ -232,18 +177,7 @@ public extension SceneBuilder {
         _AnyScene(c6),
         _AnyScene(c7),
         _AnyScene(c8),
-      ],
+      ]
-      visit: {
-        $0.visit(c0)
-        $0.visit(c1)
-        $0.visit(c2)
-        $0.visit(c3)
-        $0.visit(c4)
-        $0.visit(c5)
-        $0.visit(c6)
-        $0.visit(c7)
-        $0.visit(c8)
-      }
     )
   }
 }
@@ -276,19 +210,7 @@ public extension SceneBuilder {
         _AnyScene(c7),
         _AnyScene(c8),
         _AnyScene(c9),
-      ],
+      ]
-      visit: {
-        $0.visit(c0)
-        $0.visit(c1)
-        $0.visit(c2)
-        $0.visit(c3)
-        $0.visit(c4)
-        $0.visit(c5)
-        $0.visit(c6)
-        $0.visit(c7)
-        $0.visit(c8)
-        $0.visit(c9)
-      }
     )
   }
 }

Sources/TokamakCore/App/Scenes/SceneStorage.swift

@@ -23,8 +23,7 @@ public enum _DefaultSceneStorageProvider {
   public static var `default`: _StorageProvider!
 }
 
-@propertyWrapper
+@propertyWrapper public struct SceneStorage<Value>: DynamicProperty {
-public struct SceneStorage<Value>: DynamicProperty {
   let key: String
   let defaultValue: Value
   let store: (_StorageProvider, String, Value) -> ()

Sources/TokamakCore/App/Scenes/WindowGroup.swift

@@ -75,8 +75,4 @@ public struct WindowGroup<Content>: Scene, TitledScene where Content: View {
 //  public init(_ titleKey: LocalizedStringKey,
 //              @ViewBuilder content: () -> Content) {
 //  }
-
-  public func _visitChildren<V>(_ visitor: V) where V: SceneVisitor {
-    visitor.visit(content)
-  }
 }

Sources/TokamakCore/App/_AnyApp.swift

@@ -42,7 +42,7 @@ public struct _AnyApp: App {
   }
 
   @_spi(TokamakCore)
-  public static func _launch(_ app: Self, with configuration: _AppConfiguration) {
+  public static func _launch(_ app: Self, _ rootEnvironment: EnvironmentValues) {
     fatalError("`_AnyApp` cannot be launched. Access underlying `app` value.")
   }
 
@@ -51,10 +51,6 @@ public struct _AnyApp: App {
     fatalError("`title` cannot be set for `AnyApp`. Access underlying `app` value.")
   }
 
-  public static var _configuration: _AppConfiguration {
-    fatalError("`configuration` cannot be set for `AnyApp`. Access underlying `app` value.")
-  }
-
   @_spi(TokamakCore)
   public var _phasePublisher: AnyPublisher<ScenePhase, Never> {
     fatalError("`_AnyApp` cannot monitor scenePhase. Access underlying `app` value.")

Sources/TokamakCore/App/_TupleScene.swift

@@ -17,17 +17,11 @@
 
 struct _TupleScene<T>: Scene, GroupScene {
   let value: T
-  let children: [_AnyScene]
+  var children: [_AnyScene]
-  let visit: (SceneVisitor) -> ()
 
-  init(
+  init(_ value: T, children: [_AnyScene]) {
-    _ value: T,
-    children: [_AnyScene],
-    visit: @escaping (SceneVisitor) -> ()
-  ) {
     self.value = value
     self.children = children
-    self.visit = visit
   }
 
   var body: Never {

Sources/TokamakCore/Environment/Environment.swift

@@ -23,8 +23,7 @@ protocol EnvironmentReader {
   mutating func setContent(from values: EnvironmentValues)
 }
 
-@propertyWrapper
+@propertyWrapper public struct Environment<Value>: DynamicProperty {
-public struct Environment<Value>: DynamicProperty {
   enum Content {
     case keyPath(KeyPath<EnvironmentValues, Value>)
     case value(Value)

Sources/TokamakCore/Environment/EnvironmentKey.swift

@@ -17,24 +17,11 @@ public protocol EnvironmentKey {
   static var defaultValue: Value { get }
 }
 
-/// This protocol defines a type which mutates the environment in some way.
+protocol EnvironmentModifier {
-/// Unlike `EnvironmentalModifier`, which reads the environment to
-/// create a `ViewModifier`.
-///
-/// It can be applied to a `View` or `ViewModifier`.
-public protocol _EnvironmentModifier {
   func modifyEnvironment(_ values: inout EnvironmentValues)
 }
 
-public extension ViewModifier where Self: _EnvironmentModifier {
+public struct _EnvironmentKeyWritingModifier<Value>: ViewModifier, EnvironmentModifier {
-  static func _makeView(_ inputs: ViewInputs<Self>) -> ViewOutputs {
-    var environment = inputs.environment.environment
-    inputs.content.modifyEnvironment(&environment)
-    return .init(inputs: inputs, environment: environment)
-  }
-}
-
-public struct _EnvironmentKeyWritingModifier<Value>: ViewModifier, _EnvironmentModifier {
   public let keyPath: WritableKeyPath<EnvironmentValues, Value>
   public let value: Value
 
@@ -45,7 +32,7 @@ public struct _EnvironmentKeyWritingModifier<Value>: ViewModifier, _EnvironmentM
 
   public typealias Body = Never
 
-  public func modifyEnvironment(_ values: inout EnvironmentValues) {
+  func modifyEnvironment(_ values: inout EnvironmentValues) {
     values[keyPath: keyPath] = value
   }
 }

Sources/TokamakCore/Environment/EnvironmentObject.swift

@@ -17,12 +17,10 @@
 
 import OpenCombineShim
 
-@propertyWrapper
+@propertyWrapper public struct EnvironmentObject<ObjectType>: DynamicProperty
-public struct EnvironmentObject<ObjectType>: DynamicProperty
   where ObjectType: ObservableObject
 {
-  @dynamicMemberLookup
+  @dynamicMemberLookup public struct Wrapper {
-  public struct Wrapper {
     internal let root: ObjectType
     public subscript<Subject>(
       dynamicMember keyPath: ReferenceWritableKeyPath<ObjectType, Subject>

Sources/TokamakCore/Environment/EnvironmentValues.swift

@@ -76,7 +76,7 @@ public extension EnvironmentValues {
   }
 }
 
-struct _EnvironmentValuesWritingModifier: ViewModifier, _EnvironmentModifier {
+struct _EnvironmentValuesWritingModifier: ViewModifier, EnvironmentModifier {
   let environmentValues: EnvironmentValues
 
   func body(content: Content) -> some View {

Sources/TokamakCore/Fiber/AlignmentID.swift

@@ -1,153 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/18/22.
-//
-
-import Foundation
-
-/// Used to identify an alignment guide.
-///
-/// Typically, you would define an alignment guide inside
-/// an extension on `HorizontalAlignment` or `VerticalAlignment`:
-///
-///     extension HorizontalAlignment {
-///       private enum MyAlignmentGuide: AlignmentID {
-///         static func defaultValue(in context: ViewDimensions) -> CGFloat {
-///           return 0.0
-///         }
-///       }
-///       public static let myAlignmentGuide = Self(MyAlignmentGuide.self)
-///     }
-///
-/// Which you can then use with the `alignmentGuide` modifier:
-///
-///     VStack(alignment: .myAlignmentGuide) {
-///       Text("Align Leading")
-///         .border(.red)
-///         .alignmentGuide(.myAlignmentGuide) { $0[.leading] }
-///       Text("Align Trailing")
-///         .border(.blue)
-///         .alignmentGuide(.myAlignmentGuide) { $0[.trailing] }
-///     }
-///     .border(.green)
-public protocol AlignmentID {
-  /// The default value for this alignment guide
-  /// when not set via the `alignmentGuide` modifier.
-  static func defaultValue(in context: ViewDimensions) -> CGFloat
-}
-
-/// An alignment position along the horizontal axis.
-@frozen
-public struct HorizontalAlignment: Equatable {
-  public static func == (lhs: Self, rhs: Self) -> Bool {
-    lhs.id == rhs.id
-  }
-
-  let id: AlignmentID.Type
-
-  public init(_ id: AlignmentID.Type) {
-    self.id = id
-  }
-}
-
-extension HorizontalAlignment {
-  public static let leading = Self(Leading.self)
-
-  private enum Leading: AlignmentID {
-    static func defaultValue(in context: ViewDimensions) -> CGFloat {
-      0
-    }
-  }
-
-  public static let center = Self(Center.self)
-
-  private enum Center: AlignmentID {
-    static func defaultValue(in context: ViewDimensions) -> CGFloat {
-      context.width / 2
-    }
-  }
-
-  public static let trailing = Self(Trailing.self)
-
-  private enum Trailing: AlignmentID {
-    static func defaultValue(in context: ViewDimensions) -> CGFloat {
-      context.width
-    }
-  }
-}
-
-@frozen
-public struct VerticalAlignment: Equatable {
-  public static func == (lhs: Self, rhs: Self) -> Bool {
-    lhs.id == rhs.id
-  }
-
-  let id: AlignmentID.Type
-
-  public init(_ id: AlignmentID.Type) {
-    self.id = id
-  }
-}
-
-extension VerticalAlignment {
-  public static let top = Self(Top.self)
-  private enum Top: AlignmentID {
-    static func defaultValue(in context: ViewDimensions) -> CGFloat {
-      0
-    }
-  }
-
-  public static let center = Self(Center.self)
-  private enum Center: AlignmentID {
-    static func defaultValue(in context: ViewDimensions) -> CGFloat {
-      context.height / 2
-    }
-  }
-
-  public static let bottom = Self(Bottom.self)
-  private enum Bottom: AlignmentID {
-    static func defaultValue(in context: ViewDimensions) -> CGFloat {
-      context.height
-    }
-  }
-
-  // TODO: Add baseline vertical alignment guides.
-  // public static let firstTextBaseline: VerticalAlignment
-  // public static let lastTextBaseline: VerticalAlignment
-}
-
-/// An alignment in both axes.
-public struct Alignment: Equatable {
-  public var horizontal: HorizontalAlignment
-  public var vertical: VerticalAlignment
-
-  public init(
-    horizontal: HorizontalAlignment,
-    vertical: VerticalAlignment
-  ) {
-    self.horizontal = horizontal
-    self.vertical = vertical
-  }
-
-  public static let topLeading = Self(horizontal: .leading, vertical: .top)
-  public static let top = Self(horizontal: .center, vertical: .top)
-  public static let topTrailing = Self(horizontal: .trailing, vertical: .top)
-  public static let leading = Self(horizontal: .leading, vertical: .center)
-  public static let center = Self(horizontal: .center, vertical: .center)
-  public static let trailing = Self(horizontal: .trailing, vertical: .center)
-  public static let bottomLeading = Self(horizontal: .leading, vertical: .bottom)
-  public static let bottom = Self(horizontal: .center, vertical: .bottom)
-  public static let bottomTrailing = Self(horizontal: .trailing, vertical: .bottom)
-}

Sources/TokamakCore/Fiber/App/AppVisitor.swift

@@ -1,21 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 5/31/22.
-//
-
-/// A type that can visit an `App`.
-public protocol AppVisitor: ViewVisitor {
-  func visit<A: App>(_ app: A)
-}

Sources/TokamakCore/Fiber/Fiber+Content.swift

@@ -1,65 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 5/31/22.
-//
-
-import Foundation
-
-public extension FiberReconciler.Fiber {
-  enum Content {
-    /// The underlying `App` instance and a function to visit it generically.
-    case app(Any, visit: (AppVisitor) -> ())
-    /// The underlying `Scene` instance and a function to visit it generically.
-    case scene(Any, visit: (SceneVisitor) -> ())
-    /// The underlying `View` instance and a function to visit it generically.
-    case view(Any, visit: (ViewVisitor) -> ())
-  }
-
-  /// Create a `Content` value for a given `App`.
-  func content<A: App>(for app: A) -> Content {
-    .app(
-      app,
-      visit: { [weak self] in
-        guard case let .app(app, _) = self?.content else { return }
-        // swiftlint:disable:next force_cast
-        $0.visit(app as! A)
-      }
-    )
-  }
-
-  /// Create a `Content` value for a given `Scene`.
-  func content<S: Scene>(for scene: S) -> Content {
-    .scene(
-      scene,
-      visit: { [weak self] in
-        guard case let .scene(scene, _) = self?.content else { return }
-        // swiftlint:disable:next force_cast
-        $0.visit(scene as! S)
-      }
-    )
-  }
-
-  /// Create a `Content` value for a given `View`.
-  func content<V: View>(for view: V) -> Content {
-    .view(
-      view,
-      visit: { [weak self] in
-        guard case let .view(view, _) = self?.content else { return }
-        // swiftlint:disable:next force_cast
-        $0.visit(view as! V)
-      }
-    )
-  }
-}

Sources/TokamakCore/Fiber/Fiber+CustomDebugStringConvertible.swift

@@ -1,46 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 5/30/22.
-//
-
-extension FiberReconciler.Fiber: CustomDebugStringConvertible {
-  public var debugDescription: String {
-    let memoryAddress = String(format: "%010p", unsafeBitCast(self, to: Int.self))
-    if case let .view(view, _) = content,
-       let text = view as? Text
-    {
-      return "Text(\"\(text.storage.rawText)\") (\(memoryAddress))"
-    }
-    return "\(typeInfo?.name ?? "Unknown") (\(memoryAddress))"
-  }
-
-  private func flush(level: Int = 0) -> String {
-    let spaces = String(repeating: " ", count: level)
-    let geometry = geometry ?? .init(
-      origin: .init(origin: .zero),
-      dimensions: .init(size: .zero, alignmentGuides: [:]),
-      proposal: .unspecified
-    )
-    return """
-    \(spaces)\(String(describing: typeInfo?.type ?? Any.self)
-      .split(separator: "<")[0])\(element != nil ? "(\(element!))" : "") {\(element != nil ?
-      "\n\(spaces)geometry: \(geometry)" :
-      "")
-    \(child?.flush(level: level + 2) ?? "")
-    \(spaces)}
-    \(sibling?.flush(level: level) ?? "")
-    """
-  }
-}

Sources/TokamakCore/Fiber/Fiber.swift

@@ -1,626 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/15/22.
-//
-
-import Foundation
-import OpenCombineShim
-
-// swiftlint:disable type_body_length
-@_spi(TokamakCore)
-public extension FiberReconciler {
-  /// A manager for a single `View`.
-  ///
-  /// There are always 2 `Fiber`s for every `View` in the tree,
-  /// a current `Fiber`, and a work in progress `Fiber`.
-  /// They point to each other using the `alternate` property.
-  ///
-  /// The current `Fiber` represents the `View` as it is currently rendered on the screen.
-  /// The work in progress `Fiber` (the `alternate` of current),
-  /// is used in the reconciler to compute the new tree.
-  ///
-  /// When reconciling, the tree is recomputed from
-  /// the root of the state change on the work in progress `Fiber`.
-  /// Each node in the fiber tree is updated to apply any changes,
-  /// and a list of mutations needed to get the rendered output to match is created.
-  ///
-  /// After the entire tree has been traversed, the current and work in progress trees are swapped,
-  /// making the updated tree the current one,
-  /// and leaving the previous current tree available to apply future changes on.
-  final class Fiber {
-    weak var reconciler: FiberReconciler<Renderer>?
-
-    /// The underlying value behind this `Fiber`. Either a `Scene` or `View` instance.
-    ///
-    /// Stored as an IUO because it uses `bindProperties` to create the underlying instance,
-    /// and captures a weak reference to `self` in the visitor function,
-    /// which requires all stored properties be set before capturing.
-    @_spi(TokamakCore)
-    public var content: Content!
-
-    /// Outputs from evaluating `View._makeView`
-    ///
-    /// Stored as an IUO because creating `ViewOutputs` depends on
-    /// the `bindProperties` method, which requires
-    /// all stored properties be set before using.
-    /// `outputs` is guaranteed to be set in the initializer.
-    var outputs: ViewOutputs!
-
-    /// The erased `Layout` to use for this content.
-    ///
-    /// Stored as an IUO because it uses `bindProperties` to create the underlying instance.
-    var layout: AnyLayout?
-
-    /// The identity of this `View`
-    var id: Identity?
-
-    /// The mounted element, if this is a `Renderer` primitive.
-    var element: Renderer.ElementType?
-
-    /// The index of this element in its `elementParent`
-    var elementIndex: Int?
-
-    /// The first child node.
-    @_spi(TokamakCore)
-    public var child: Fiber?
-
-    /// This node's right sibling.
-    @_spi(TokamakCore)
-    public var sibling: Fiber?
-
-    /// An unowned reference to the parent node.
-    ///
-    /// Parent references are `unowned` (as opposed to `weak`)
-    /// because the parent will always exist if a child does.
-    /// If the parent is released, the child is released with it.
-    @_spi(TokamakCore)
-    public unowned var parent: Fiber?
-
-    /// The nearest parent that can be mounted on.
-    unowned var elementParent: Fiber?
-
-    /// The nearest parent that receives preferences.
-    unowned var preferenceParent: Fiber?
-
-    /// The cached type information for the underlying `View`.
-    var typeInfo: TypeInfo?
-
-    /// Boxes that store `State` data.
-    var state: [PropertyInfo: MutableStorage] = [:]
-
-    /// Subscribed `Cancellable`s keyed with the property contained the observable.
-    ///
-    /// Each time properties are bound, a new subscription could be created.
-    /// When the subscription is overridden, the old cancellable is released.
-    var subscriptions: [PropertyInfo: AnyCancellable] = [:]
-
-    /// Storage for `PreferenceKey` values as they are passed up the tree.
-    var preferences: _PreferenceStore?
-
-    /// The computed dimensions and origin.
-    var geometry: ViewGeometry?
-
-    /// The WIP node if this is current, or the current node if this is WIP.
-    @_spi(TokamakCore)
-    public weak var alternate: Fiber?
-
-    var createAndBindAlternate: (() -> Fiber?)?
-
-    /// A box holding a value for an `@State` property wrapper.
-    /// Will call `onSet` (usually a `Reconciler.reconcile` call) when updated.
-    final class MutableStorage {
-      private(set) var value: Any
-      let onSet: () -> ()
-
-      func setValue(_ newValue: Any, with transaction: Transaction) {
-        value = newValue
-        onSet()
-      }
-
-      init(initialValue: Any, onSet: @escaping () -> ()) {
-        value = initialValue
-        self.onSet = onSet
-      }
-    }
-
-    public enum Identity: Hashable {
-      case explicit(AnyHashable)
-      case structural(index: Int)
-    }
-
-    init<V: View>(
-      _ view: inout V,
-      element: Renderer.ElementType?,
-      parent: Fiber?,
-      elementParent: Fiber?,
-      preferenceParent: Fiber?,
-      elementIndex: Int?,
-      traits: _ViewTraitStore?,
-      reconciler: FiberReconciler<Renderer>?
-    ) {
-      self.reconciler = reconciler
-      child = nil
-      sibling = nil
-      self.parent = parent
-      self.elementParent = elementParent
-      self.preferenceParent = preferenceParent
-      typeInfo = TokamakCore.typeInfo(of: V.self)
-
-      let environment = parent?.outputs.environment ?? .init(.init())
-      bindProperties(to: &view, typeInfo, environment.environment)
-      var updateView = view
-      let viewInputs = ViewInputs(
-        content: view,
-        updateContent: { $0(&updateView) },
-        environment: environment,
-        traits: traits,
-        preferenceStore: preferences
-      )
-      outputs = V._makeView(viewInputs)
-      if let preferenceStore = outputs.preferenceStore {
-        preferences = preferenceStore
-      }
-      view = updateView
-      content = content(for: view)
-
-      if let element = element {
-        self.element = element
-      } else if Renderer.isPrimitive(view) {
-        self.element = .init(
-          from: .init(from: view, useDynamicLayout: reconciler?.renderer.useDynamicLayout ?? false)
-        )
-      }
-
-      if self.element != nil {
-        layout = (view as? _AnyLayout)?._erased() ?? DefaultLayout.shared
-      }
-
-      // Only specify an `elementIndex` if we have an element.
-      if self.element != nil {
-        self.elementIndex = elementIndex
-      }
-
-      let alternateView = view
-      createAndBindAlternate = { [weak self] in
-        guard let self = self else { return nil }
-        // Create the alternate lazily
-        let alternate = Fiber(
-          bound: alternateView,
-          state: self.state,
-          subscriptions: self.subscriptions,
-          preferences: self.preferences,
-          layout: self.layout,
-          alternate: self,
-          outputs: self.outputs,
-          typeInfo: self.typeInfo,
-          element: self.element,
-          parent: self.parent?.alternate,
-          elementParent: self.elementParent?.alternate,
-          preferenceParent: self.preferenceParent?.alternate,
-          reconciler: reconciler
-        )
-        self.alternate = alternate
-        if self.parent?.child === self {
-          self.parent?.alternate?.child = alternate // Link it with our parent's alternate.
-        } else {
-          // Find our left sibling.
-          var node = self.parent?.child
-          while node?.sibling !== self {
-            guard node?.sibling != nil else { return alternate }
-            node = node?.sibling
-          }
-          if node?.sibling === self {
-            node?.alternate?.sibling = alternate // Link it with our left sibling's alternate.
-          }
-        }
-        return alternate
-      }
-    }
-
-    init<V: View>(
-      bound view: V,
-      state: [PropertyInfo: MutableStorage],
-      subscriptions: [PropertyInfo: AnyCancellable],
-      preferences: _PreferenceStore?,
-      layout: AnyLayout!,
-      alternate: Fiber,
-      outputs: ViewOutputs,
-      typeInfo: TypeInfo?,
-      element: Renderer.ElementType?,
-      parent: FiberReconciler<Renderer>.Fiber?,
-      elementParent: Fiber?,
-      preferenceParent: Fiber?,
-      reconciler: FiberReconciler<Renderer>?
-    ) {
-      self.alternate = alternate
-      self.reconciler = reconciler
-      self.element = element
-      child = nil
-      sibling = nil
-      self.parent = parent
-      self.elementParent = elementParent
-      self.preferenceParent = preferenceParent
-      self.typeInfo = typeInfo
-      self.outputs = outputs
-      self.state = state
-      self.subscriptions = subscriptions
-      self.preferences = preferences
-      if element != nil {
-        self.layout = layout
-      }
-      content = content(for: view)
-    }
-
-    private func bindProperties<T>(
-      to content: inout T,
-      _ typeInfo: TypeInfo?,
-      _ environment: EnvironmentValues
-    ) {
-      var erased: Any = content
-      bindProperties(to: &erased, typeInfo, environment)
-      // swiftlint:disable:next force_cast
-      content = erased as! T
-    }
-
-    /// Collect `DynamicProperty`s and link their state changes to the reconciler.
-    private func bindProperties(
-      to content: inout Any,
-      _ typeInfo: TypeInfo?,
-      _ environment: EnvironmentValues
-    ) {
-      guard let typeInfo = typeInfo else { return }
-
-      for property in typeInfo.properties where property.type is DynamicProperty.Type {
-        var value = property.get(from: content)
-        // Bind nested properties.
-        bindProperties(to: &value, TokamakCore.typeInfo(of: property.type), environment)
-        // Create boxes for `@State` and other mutable properties.
-        if var storage = value as? WritableValueStorage {
-          let box = self.state[property] ?? MutableStorage(
-            initialValue: storage.anyInitialValue,
-            onSet: { [weak self] in
-              guard let self = self else { return }
-              self.reconciler?.fiberChanged(self)
-            }
-          )
-          state[property] = box
-          storage.getter = { box.value }
-          storage.setter = { box.setValue($0, with: $1) }
-          value = storage
-          // Create boxes for `@StateObject` and other immutable properties.
-        } else if var storage = value as? ValueStorage {
-          let box = self.state[property] ?? MutableStorage(
-            initialValue: storage.anyInitialValue,
-            onSet: {}
-          )
-          state[property] = box
-          storage.getter = { box.value }
-          value = storage
-          // Read from the environment.
-        } else if var environmentReader = value as? EnvironmentReader {
-          environmentReader.setContent(from: environment)
-          value = environmentReader
-        }
-        // Subscribe to observable properties.
-        if let observed = value as? ObservedProperty {
-          subscriptions[property] = observed.objectWillChange.sink { [weak self] _ in
-            guard let self = self else { return }
-            self.reconciler?.fiberChanged(self)
-          }
-        }
-        property.set(value: value, on: &content)
-      }
-      if var environmentReader = content as? EnvironmentReader {
-        environmentReader.setContent(from: environment)
-        content = environmentReader
-      }
-    }
-
-    /// Call `update()` on each `DynamicProperty` in the type.
-    private func updateDynamicProperties(
-      of content: inout Any,
-      _ typeInfo: TypeInfo?
-    ) {
-      guard let typeInfo = typeInfo else { return }
-      for property in typeInfo.properties where property.type is DynamicProperty.Type {
-        var value = property.get(from: content)
-        // Update nested properties.
-        updateDynamicProperties(of: &value, TokamakCore.typeInfo(of: property.type))
-        // swiftlint:disable:next force_cast
-        var dynamicProperty = value as! DynamicProperty
-        dynamicProperty.update()
-        property.set(value: dynamicProperty, on: &content)
-      }
-    }
-
-    /// Update each `DynamicProperty` in our content.
-    func updateDynamicProperties() {
-      guard let content = content else { return }
-      switch content {
-      case .app(var app, let visit):
-        updateDynamicProperties(of: &app, typeInfo)
-        self.content = .app(app, visit: visit)
-      case .scene(var scene, let visit):
-        updateDynamicProperties(of: &scene, typeInfo)
-        self.content = .scene(scene, visit: visit)
-      case .view(var view, let visit):
-        updateDynamicProperties(of: &view, typeInfo)
-        self.content = .view(view, visit: visit)
-      }
-    }
-
-    func update<V: View>(
-      with view: inout V,
-      elementIndex: Int?,
-      traits: _ViewTraitStore?
-    ) -> Renderer.ElementType.Content? {
-      typeInfo = TokamakCore.typeInfo(of: V.self)
-
-      self.elementIndex = elementIndex
-
-      let environment = parent?.outputs.environment ?? .init(.init())
-      bindProperties(to: &view, typeInfo, environment.environment)
-      var updateView = view
-      let inputs = ViewInputs(
-        content: view,
-        updateContent: {
-          $0(&updateView)
-        },
-        environment: environment,
-        traits: traits,
-        preferenceStore: preferences
-      )
-      outputs = V._makeView(inputs)
-      view = updateView
-      content = content(for: view)
-
-      if element != nil {
-        layout = (view as? _AnyLayout)?._erased() ?? DefaultLayout.shared
-      }
-
-      if Renderer.isPrimitive(view) {
-        return .init(from: view, useDynamicLayout: reconciler?.renderer.useDynamicLayout ?? false)
-      } else {
-        return nil
-      }
-    }
-
-    init<A: App>(
-      _ app: inout A,
-      rootElement: Renderer.ElementType,
-      rootEnvironment: EnvironmentValues,
-      reconciler: FiberReconciler<Renderer>
-    ) {
-      self.reconciler = reconciler
-      child = nil
-      sibling = nil
-      // `App`s are always the root, so they can have no parent.
-      parent = nil
-      elementParent = nil
-      preferenceParent = nil
-      element = rootElement
-      typeInfo = TokamakCore.typeInfo(of: A.self)
-      bindProperties(to: &app, typeInfo, rootEnvironment)
-      var updateApp = app
-      outputs = .init(
-        inputs: .init(
-          content: app,
-          updateContent: {
-            $0(&updateApp)
-          },
-          environment: .init(rootEnvironment),
-          traits: .init(),
-          preferenceStore: preferences
-        )
-      )
-      if let preferenceStore = outputs.preferenceStore {
-        preferences = preferenceStore
-      }
-      app = updateApp
-      content = content(for: app)
-
-      layout = .init(RootLayout(renderer: reconciler.renderer))
-
-      let alternateApp = app
-      createAndBindAlternate = { [weak self] in
-        guard let self = self else { return nil }
-        // Create the alternate lazily
-        let alternate = Fiber(
-          bound: alternateApp,
-          state: self.state,
-          subscriptions: self.subscriptions,
-          preferences: self.preferences,
-          layout: self.layout,
-          alternate: self,
-          outputs: self.outputs,
-          typeInfo: self.typeInfo,
-          element: self.element,
-          reconciler: reconciler
-        )
-        self.alternate = alternate
-        return alternate
-      }
-    }
-
-    init<A: App>(
-      bound app: A,
-      state: [PropertyInfo: MutableStorage],
-      subscriptions: [PropertyInfo: AnyCancellable],
-      preferences: _PreferenceStore?,
-      layout: AnyLayout?,
-      alternate: Fiber,
-      outputs: SceneOutputs,
-      typeInfo: TypeInfo?,
-      element: Renderer.ElementType?,
-      reconciler: FiberReconciler<Renderer>?
-    ) {
-      self.alternate = alternate
-      self.reconciler = reconciler
-      self.element = element
-      child = nil
-      sibling = nil
-      parent = nil
-      elementParent = nil
-      preferenceParent = nil
-      self.typeInfo = typeInfo
-      self.outputs = outputs
-      self.state = state
-      self.subscriptions = subscriptions
-      self.preferences = preferences
-      self.layout = layout
-      content = content(for: app)
-    }
-
-    init<S: Scene>(
-      _ scene: inout S,
-      element: Renderer.ElementType?,
-      parent: Fiber?,
-      elementParent: Fiber?,
-      preferenceParent: Fiber?,
-      environment: EnvironmentBox?,
-      reconciler: FiberReconciler<Renderer>?
-    ) {
-      self.reconciler = reconciler
-      child = nil
-      sibling = nil
-      self.parent = parent
-      self.elementParent = elementParent
-      self.element = element
-      self.preferenceParent = preferenceParent
-      typeInfo = TokamakCore.typeInfo(of: S.self)
-
-      let environment = environment ?? parent?.outputs.environment ?? .init(.init())
-      bindProperties(to: &scene, typeInfo, environment.environment)
-      var updateScene = scene
-      outputs = S._makeScene(
-        .init(
-          content: scene,
-          updateContent: {
-            $0(&updateScene)
-          },
-          environment: environment,
-          traits: .init(),
-          preferenceStore: preferences
-        )
-      )
-      if let preferenceStore = outputs.preferenceStore {
-        preferences = preferenceStore
-      }
-      scene = updateScene
-      content = content(for: scene)
-
-      if element != nil {
-        layout = (scene as? _AnyLayout)?._erased() ?? DefaultLayout.shared
-      }
-
-      let alternateScene = scene
-      createAndBindAlternate = { [weak self] in
-        guard let self = self else { return nil }
-        // Create the alternate lazily
-        let alternate = Fiber(
-          bound: alternateScene,
-          state: self.state,
-          subscriptions: self.subscriptions,
-          preferences: self.preferences,
-          layout: self.layout,
-          alternate: self,
-          outputs: self.outputs,
-          typeInfo: self.typeInfo,
-          element: self.element,
-          parent: self.parent?.alternate,
-          elementParent: self.elementParent?.alternate,
-          preferenceParent: self.preferenceParent?.alternate,
-          reconciler: reconciler
-        )
-        self.alternate = alternate
-        if self.parent?.child === self {
-          self.parent?.alternate?.child = alternate // Link it with our parent's alternate.
-        } else {
-          // Find our left sibling.
-          var node = self.parent?.child
-          while node?.sibling !== self {
-            guard node?.sibling != nil else { return alternate }
-            node = node?.sibling
-          }
-          if node?.sibling === self {
-            node?.alternate?.sibling = alternate // Link it with our left sibling's alternate.
-          }
-        }
-        return alternate
-      }
-    }
-
-    init<S: Scene>(
-      bound scene: S,
-      state: [PropertyInfo: MutableStorage],
-      subscriptions: [PropertyInfo: AnyCancellable],
-      preferences: _PreferenceStore?,
-      layout: AnyLayout!,
-      alternate: Fiber,
-      outputs: SceneOutputs,
-      typeInfo: TypeInfo?,
-      element: Renderer.ElementType?,
-      parent: FiberReconciler<Renderer>.Fiber?,
-      elementParent: Fiber?,
-      preferenceParent: Fiber?,
-      reconciler: FiberReconciler<Renderer>?
-    ) {
-      self.alternate = alternate
-      self.reconciler = reconciler
-      self.element = element
-      child = nil
-      sibling = nil
-      self.parent = parent
-      self.elementParent = elementParent
-      self.preferenceParent = preferenceParent
-      self.typeInfo = typeInfo
-      self.outputs = outputs
-      self.state = state
-      self.subscriptions = subscriptions
-      self.preferences = preferences
-      if element != nil {
-        self.layout = layout
-      }
-      content = content(for: scene)
-    }
-
-    func update<S: Scene>(
-      with scene: inout S
-    ) -> Renderer.ElementType.Content? {
-      typeInfo = TokamakCore.typeInfo(of: S.self)
-
-      let environment = parent?.outputs.environment ?? .init(.init())
-      bindProperties(to: &scene, typeInfo, environment.environment)
-      var updateScene = scene
-      outputs = S._makeScene(.init(
-        content: scene,
-        updateContent: {
-          $0(&updateScene)
-        },
-        environment: environment,
-        traits: .init(),
-        preferenceStore: preferences
-      ))
-      scene = updateScene
-      content = content(for: scene)
-
-      if element != nil {
-        layout = (scene as? _AnyLayout)?._erased() ?? DefaultLayout.shared
-      }
-
-      return nil
-    }
-  }
-}

Sources/TokamakCore/Fiber/FiberElement.swift

@@ -1,33 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/15/22.
-//
-
-/// A reference type that points to a `Renderer`-specific element that has been mounted.
-/// For instance, a DOM node in the `DOMFiberRenderer`.
-public protocol FiberElement: AnyObject {
-  associatedtype Content: FiberElementContent
-  var content: Content { get }
-  init(from content: Content)
-  func update(with content: Content)
-}
-
-/// The data used to create an `FiberElement`.
-///
-/// We re-use `FiberElement` instances in the `Fiber` tree,
-/// but can re-create and copy `FiberElementContent` as often as needed.
-public protocol FiberElementContent: Equatable {
-  init<V: View>(from primitiveView: V, useDynamicLayout: Bool)
-}

Sources/TokamakCore/Fiber/FiberReconciler+TreeReducer.swift

@@ -1,212 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 5/28/22.
-//
-
-import Foundation
-
-extension FiberReconciler {
-  /// Convert the first level of children of a `View` into a linked list of `Fiber`s.
-  struct TreeReducer: SceneReducer {
-    final class Result {
-      // For references
-      let fiber: Fiber?
-      let visitChildren: (TreeReducer.SceneVisitor) -> ()
-      unowned var parent: Result?
-      var child: Result?
-      var sibling: Result?
-      var newContent: Renderer.ElementType.Content?
-      var elementIndices: [ObjectIdentifier: Int]
-      var nextTraits: _ViewTraitStore
-
-      // For reducing
-      var lastSibling: Result?
-      var nextExisting: Fiber?
-      var nextExistingAlternate: Fiber?
-
-      init(
-        fiber: Fiber?,
-        visitChildren: @escaping (TreeReducer.SceneVisitor) -> (),
-        parent: Result?,
-        child: Fiber?,
-        alternateChild: Fiber?,
-        newContent: Renderer.ElementType.Content? = nil,
-        elementIndices: [ObjectIdentifier: Int],
-        nextTraits: _ViewTraitStore
-      ) {
-        self.fiber = fiber
-        self.visitChildren = visitChildren
-        self.parent = parent
-        nextExisting = child
-        nextExistingAlternate = alternateChild
-        self.newContent = newContent
-        self.elementIndices = elementIndices
-        self.nextTraits = nextTraits
-      }
-    }
-
-    static func reduce<S>(into partialResult: inout Result, nextScene: S) where S: Scene {
-      Self.reduce(
-        into: &partialResult,
-        nextValue: nextScene,
-        createFiber: { scene, element, parent, elementParent, preferenceParent, _, _, reconciler in
-          Fiber(
-            &scene,
-            element: element,
-            parent: parent,
-            elementParent: elementParent,
-            preferenceParent: preferenceParent,
-            environment: nil,
-            reconciler: reconciler
-          )
-        },
-        update: { fiber, scene, _, _ in
-          fiber.update(with: &scene)
-        },
-        visitChildren: { $1._visitChildren }
-      )
-    }
-
-    static func reduce<V>(into partialResult: inout Result, nextView: V) where V: View {
-      Self.reduce(
-        into: &partialResult,
-        nextValue: nextView,
-        createFiber: {
-          view, element,
-            parent, elementParent, preferenceParent, elementIndex,
-            traits, reconciler in
-          Fiber(
-            &view,
-            element: element,
-            parent: parent,
-            elementParent: elementParent,
-            preferenceParent: preferenceParent,
-            elementIndex: elementIndex,
-            traits: traits,
-            reconciler: reconciler
-          )
-        },
-        update: { fiber, view, elementIndex, traits in
-          fiber.update(
-            with: &view,
-            elementIndex: elementIndex,
-            traits: fiber.element != nil ? traits : nil
-          )
-        },
-        visitChildren: { reconciler, view in
-          reconciler?.renderer.viewVisitor(for: view) ?? view._visitChildren
-        }
-      )
-    }
-
-    static func reduce<T>(
-      into partialResult: inout Result,
-      nextValue: T,
-      createFiber: (
-        inout T,
-        Renderer.ElementType?,
-        Fiber?,
-        Fiber?,
-        Fiber?,
-        Int?,
-        _ViewTraitStore,
-        FiberReconciler?
-      ) -> Fiber,
-      update: (Fiber, inout T, Int?, _ViewTraitStore) -> Renderer.ElementType.Content?,
-      visitChildren: (FiberReconciler?, T) -> (TreeReducer.SceneVisitor) -> ()
-    ) {
-      // Create the node and its element.
-      var nextValue = nextValue
-
-      let resultChild: Result
-      if let existing = partialResult.nextExisting {
-        // If a fiber already exists, simply update it with the new view.
-        let key: ObjectIdentifier?
-        if let elementParent = existing.elementParent {
-          key = ObjectIdentifier(elementParent)
-        } else {
-          key = nil
-        }
-        let newContent = update(
-          existing,
-          &nextValue,
-          key.map { partialResult.elementIndices[$0, default: 0] },
-          partialResult.nextTraits
-        )
-        resultChild = Result(
-          fiber: existing,
-          visitChildren: visitChildren(partialResult.fiber?.reconciler, nextValue),
-          parent: partialResult,
-          child: existing.child,
-          alternateChild: existing.alternate?.child,
-          newContent: newContent,
-          elementIndices: partialResult.elementIndices,
-          nextTraits: existing.element != nil ? .init() : partialResult.nextTraits
-        )
-        partialResult.nextExisting = existing.sibling
-        partialResult.nextExistingAlternate = partialResult.nextExistingAlternate?.sibling
-      } else {
-        let elementParent = partialResult.fiber?.element != nil
-          ? partialResult.fiber
-          : partialResult.fiber?.elementParent
-        let preferenceParent = partialResult.fiber?.preferences != nil
-          ? partialResult.fiber
-          : partialResult.fiber?.preferenceParent
-        let key: ObjectIdentifier?
-        if let elementParent = elementParent {
-          key = ObjectIdentifier(elementParent)
-        } else {
-          key = nil
-        }
-        // Otherwise, create a new fiber for this child.
-        let fiber = createFiber(
-          &nextValue,
-          partialResult.nextExistingAlternate?.element,
-          partialResult.fiber,
-          elementParent,
-          preferenceParent,
-          key.map { partialResult.elementIndices[$0, default: 0] },
-          partialResult.nextTraits,
-          partialResult.fiber?.reconciler
-        )
-
-        // If a fiber already exists for an alternate, link them.
-        if let alternate = partialResult.nextExistingAlternate {
-          fiber.alternate = alternate
-          partialResult.nextExistingAlternate = alternate.sibling
-        }
-        resultChild = Result(
-          fiber: fiber,
-          visitChildren: visitChildren(partialResult.fiber?.reconciler, nextValue),
-          parent: partialResult,
-          child: nil,
-          alternateChild: fiber.alternate?.child,
-          elementIndices: partialResult.elementIndices,
-          nextTraits: fiber.element != nil ? .init() : partialResult.nextTraits
-        )
-      }
-      // Get the last child element we've processed, and add the new child as its sibling.
-      if let lastSibling = partialResult.lastSibling {
-        lastSibling.fiber?.sibling = resultChild.fiber
-        lastSibling.sibling = resultChild
-      } else {
-        // Otherwise setup the first child
-        partialResult.fiber?.child = resultChild.fiber
-        partialResult.child = resultChild
-      }
-      partialResult.lastSibling = resultChild
-    }
-  }
-}

Sources/TokamakCore/Fiber/FiberReconciler.swift

@@ -1,290 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/15/22.
-//
-
-import Foundation
-import OpenCombineShim
-
-/// A reconciler modeled after React's
-/// [Fiber reconciler](https://reactjs.org/docs/faq-internals.html#what-is-react-fiber)
-public final class FiberReconciler<Renderer: FiberRenderer> {
-  /// The root node in the `Fiber` tree that represents the `View`s currently rendered on screen.
-  @_spi(TokamakCore)
-  public var current: Fiber!
-
-  /// The alternate of `current`, or the work in progress tree root.
-  ///
-  /// We must keep a strong reference to both the current and alternate tree roots,
-  /// as they only keep weak references to each other.
-  private var alternate: Fiber!
-
-  /// The `FiberRenderer` used to create and update the `Element`s on screen.
-  public let renderer: Renderer
-
-  /// Enabled passes to run on each `reconcile(from:)` call.
-  private let passes: [FiberReconcilerPass]
-
-  private let caches: Caches
-
-  private var sceneSizeCancellable: AnyCancellable?
-
-  private var isReconciling = false
-  /// The identifiers for each `Fiber` that changed state during the last run loop.
-  ///
-  /// The reconciler loop starts at the root of the `View` hierarchy
-  /// to ensure all preference values are passed down correctly.
-  /// To help mitigate performance issues related to this, we only perform reconcile
-  /// checks when we reach a changed `Fiber`.
-  private var changedFibers = Set<ObjectIdentifier>()
-  public var afterReconcileActions = [() -> ()]()
-
-  struct RootView<Content: View>: View {
-    let content: Content
-    let reconciler: FiberReconciler<Renderer>
-
-    var environment: EnvironmentValues {
-      var environment = reconciler.renderer.defaultEnvironment
-      environment.measureText = reconciler.renderer.measureText
-      environment.measureImage = reconciler.renderer.measureImage
-      environment.afterReconcile = reconciler.afterReconcile
-      return environment
-    }
-
-    var body: some View {
-      RootLayout(renderer: reconciler.renderer).callAsFunction {
-        content
-          .environmentValues(environment)
-      }
-    }
-  }
-
-  /// The `Layout` container for the root of a `View` hierarchy.
-  ///
-  /// Simply places each `View` in the center of its bounds.
-  struct RootLayout: Layout {
-    let renderer: Renderer
-
-    func sizeThatFits(
-      proposal: ProposedViewSize,
-      subviews: Subviews,
-      cache: inout ()
-    ) -> CGSize {
-      renderer.sceneSize.value
-    }
-
-    func placeSubviews(
-      in bounds: CGRect,
-      proposal: ProposedViewSize,
-      subviews: Subviews,
-      cache: inout ()
-    ) {
-      for subview in subviews {
-        subview.place(
-          at: .init(x: bounds.midX, y: bounds.midY),
-          anchor: .center,
-          proposal: .init(width: bounds.width, height: bounds.height)
-        )
-      }
-    }
-  }
-
-  public init<V: View>(_ renderer: Renderer, _ view: V) {
-    self.renderer = renderer
-    if renderer.useDynamicLayout {
-      passes = [.reconcile, .layout]
-    } else {
-      passes = [.reconcile]
-    }
-    caches = Caches()
-    var view = RootView(content: view, reconciler: self)
-    current = .init(
-      &view,
-      element: renderer.rootElement,
-      parent: nil,
-      elementParent: nil,
-      preferenceParent: nil,
-      elementIndex: 0,
-      traits: nil,
-      reconciler: self
-    )
-    // Start by building the initial tree.
-    alternate = current.createAndBindAlternate?()
-
-    sceneSizeCancellable = renderer.sceneSize.removeDuplicates().sink { [weak self] _ in
-      guard let self = self else { return }
-      self.fiberChanged(self.current)
-    }
-  }
-
-  public init<A: App>(_ renderer: Renderer, _ app: A) {
-    self.renderer = renderer
-    if renderer.useDynamicLayout {
-      passes = [.reconcile, .layout]
-    } else {
-      passes = [.reconcile]
-    }
-    caches = Caches()
-    var environment = renderer.defaultEnvironment
-    environment.measureText = renderer.measureText
-    environment.measureImage = renderer.measureImage
-    environment.afterReconcile = afterReconcile
-    var app = app
-    current = .init(
-      &app,
-      rootElement: renderer.rootElement,
-      rootEnvironment: environment,
-      reconciler: self
-    )
-    // Start by building the initial tree.
-    alternate = current.createAndBindAlternate?()
-
-    sceneSizeCancellable = renderer.sceneSize.removeDuplicates().sink { [weak self] _ in
-      guard let self = self else { return }
-      self.fiberChanged(self.current)
-    }
-  }
-
-  /// A visitor that performs each pass used by the `FiberReconciler`.
-  final class ReconcilerVisitor: AppVisitor, SceneVisitor, ViewVisitor {
-    let root: Fiber
-    /// Any `Fiber`s that changed state during the last run loop.
-    let changedFibers: Set<ObjectIdentifier>
-    unowned let reconciler: FiberReconciler
-    var mutations = [Mutation<Renderer>]()
-
-    init(root: Fiber, changedFibers: Set<ObjectIdentifier>, reconciler: FiberReconciler) {
-      self.root = root
-      self.changedFibers = changedFibers
-      self.reconciler = reconciler
-    }
-
-    func visit<A>(_ app: A) where A: App {
-      visitAny(app) { $0.visit(app.body) }
-    }
-
-    func visit<S>(_ scene: S) where S: Scene {
-      visitAny(scene, scene._visitChildren)
-    }
-
-    func visit<V>(_ view: V) where V: View {
-      visitAny(view, reconciler.renderer.viewVisitor(for: view))
-    }
-
-    private func visitAny(
-      _ content: Any,
-      _ visitChildren: @escaping (TreeReducer.SceneVisitor) -> ()
-    ) {
-      let alternateRoot: Fiber?
-      if let alternate = root.alternate {
-        alternateRoot = alternate
-      } else {
-        alternateRoot = root.createAndBindAlternate?()
-      }
-      let rootResult = TreeReducer.Result(
-        fiber: alternateRoot, // The alternate is the WIP node.
-        visitChildren: visitChildren,
-        parent: nil,
-        child: alternateRoot?.child,
-        alternateChild: root.child,
-        elementIndices: [:],
-        nextTraits: .init()
-      )
-      reconciler.caches.clear()
-      for pass in reconciler.passes {
-        pass.run(
-          in: reconciler,
-          root: rootResult,
-          changedFibers: changedFibers,
-          caches: reconciler.caches
-        )
-      }
-      mutations = reconciler.caches.mutations
-    }
-  }
-
-  func afterReconcile(_ action: @escaping () -> ()) {
-    guard isReconciling == true
-    else {
-      action()
-      return
-    }
-    afterReconcileActions.append(action)
-  }
-
-  /// Called by any `Fiber` that experiences a state change.
-  ///
-  /// Reconciliation only runs after every change during the current run loop has been performed.
-  func fiberChanged(_ fiber: Fiber) {
-    guard let alternate = fiber.alternate ?? fiber.createAndBindAlternate?()
-    else { return }
-    let shouldSchedule = changedFibers.isEmpty
-    changedFibers.insert(ObjectIdentifier(alternate))
-    if shouldSchedule {
-      renderer.schedule { [weak self] in
-        self?.reconcile()
-      }
-    }
-  }
-
-  /// Perform each `FiberReconcilerPass` given the `changedFibers`.
-  ///
-  /// A `reconcile()` call is queued from `fiberChanged` once per run loop.
-  func reconcile() {
-    isReconciling = true
-    let changedFibers = changedFibers
-    self.changedFibers.removeAll()
-    // Create a list of mutations.
-    let visitor = ReconcilerVisitor(root: current, changedFibers: changedFibers, reconciler: self)
-    switch current.content {
-    case let .view(_, visit):
-      visit(visitor)
-    case let .scene(_, visit):
-      visit(visitor)
-    case let .app(_, visit):
-      visit(visitor)
-    case .none:
-      break
-    }
-
-    // Apply mutations to the rendered output.
-    renderer.commit(visitor.mutations)
-
-    // Swap the root out for its alternate.
-    // Essentially, making the work in progress tree the current,
-    // and leaving the current available to be the work in progress
-    // on our next update.
-    let alternate = alternate
-    self.alternate = current
-    current = alternate
-
-    isReconciling = false
-
-    for action in afterReconcileActions {
-      action()
-    }
-  }
-}
-
-public extension EnvironmentValues {
-  private enum AfterReconcileKey: EnvironmentKey {
-    static let defaultValue: (@escaping () -> ()) -> () = { _ in }
-  }
-
-  var afterReconcile: (@escaping () -> ()) -> () {
-    get { self[AfterReconcileKey.self] }
-    set { self[AfterReconcileKey.self] = newValue }
-  }
-}

Sources/TokamakCore/Fiber/FiberRenderer.swift

@@ -1,145 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/15/22.
-//
-
-import Foundation
-import OpenCombineShim
-
-/// A renderer capable of performing mutations specified by a `FiberReconciler`.
-public protocol FiberRenderer {
-  /// The element class this renderer uses.
-  associatedtype ElementType: FiberElement
-
-  /// Check whether a `View` is a primitive for this renderer.
-  static func isPrimitive<V>(_ view: V) -> Bool where V: View
-
-  /// Override the default `_visitChildren` implementation for a primitive `View`.
-  func visitPrimitiveChildren<Primitive, Visitor>(
-    _ view: Primitive
-  ) -> ViewVisitorF<Visitor>? where Primitive: View, Visitor: ViewVisitor
-
-  /// Apply the mutations to the elements.
-  func commit(_ mutations: [Mutation<Self>])
-
-  /// The root element all top level views should be mounted on.
-  var rootElement: ElementType { get }
-
-  /// The smallest set of initial `EnvironmentValues` needed for this renderer to function.
-  var defaultEnvironment: EnvironmentValues { get }
-
-  /// The size of the window we are rendering in.
-  ///
-  /// Layout is automatically updated whenever the size changes.
-  var sceneSize: CurrentValueSubject<CGSize, Never> { get }
-
-  /// Whether layout is enabled for this renderer.
-  var useDynamicLayout: Bool { get }
-
-  /// Calculate the size of `Text` in `environment` for layout.
-  func measureText(
-    _ text: Text,
-    proposal: ProposedViewSize,
-    in environment: EnvironmentValues
-  ) -> CGSize
-
-  /// Calculate the size of an `Image` in `environment` for layout.
-  func measureImage(
-    _ image: Image,
-    proposal: ProposedViewSize,
-    in environment: EnvironmentValues
-  ) -> CGSize
-
-  /// Run `action` on the next run loop.
-  ///
-  /// Called by the `FiberReconciler` to perform reconciliation after all changed Fibers are collected.
-  ///
-  /// For example, take the following sample `View`:
-  ///
-  ///     struct DuelOfTheStates: View {
-  ///       @State private var hits1 = 0
-  ///       @State private var hits2 = 0
-  ///
-  ///       var body: some View {
-  ///         Button("Hit") {
-  ///           hits1 += 1
-  ///           hits2 += 2
-  ///         }
-  ///       }
-  ///     }
-  ///
-  /// When the button is pressed, both `hits1` and `hits2` are updated.
-  /// If reconciliation was done on every state change, we would needlessly run it twice,
-  /// once for `hits1` and again for `hits2`.
-  ///
-  /// Instead, we create a list of changed fibers
-  /// (in this case just `DuelOfTheStates` as both properties were on it),
-  /// and reconcile after all changes have been collected.
-  func schedule(_ action: @escaping () -> ())
-}
-
-public extension FiberRenderer {
-  var defaultEnvironment: EnvironmentValues { .init() }
-
-  func visitPrimitiveChildren<Primitive, Visitor>(
-    _ view: Primitive
-  ) -> ViewVisitorF<Visitor>? where Primitive: View, Visitor: ViewVisitor {
-    nil
-  }
-
-  func viewVisitor<V: View, Visitor: ViewVisitor>(for view: V) -> ViewVisitorF<Visitor> {
-    if Self.isPrimitive(view) {
-      return visitPrimitiveChildren(view) ?? view._visitChildren
-    } else {
-      return view._visitChildren
-    }
-  }
-
-  @discardableResult
-  @_disfavoredOverload
-  func render<V: View>(_ view: V) -> FiberReconciler<Self> {
-    .init(self, view)
-  }
-
-  @discardableResult
-  @_disfavoredOverload
-  func render<A: App>(_ app: A) -> FiberReconciler<Self> {
-    .init(self, app)
-  }
-}
-
-extension EnvironmentValues {
-  private enum MeasureTextKey: EnvironmentKey {
-    static var defaultValue: (Text, ProposedViewSize, EnvironmentValues) -> CGSize {
-      { _, _, _ in .zero }
-    }
-  }
-
-  var measureText: (Text, ProposedViewSize, EnvironmentValues) -> CGSize {
-    get { self[MeasureTextKey.self] }
-    set { self[MeasureTextKey.self] = newValue }
-  }
-
-  private enum MeasureImageKey: EnvironmentKey {
-    static var defaultValue: (Image, ProposedViewSize, EnvironmentValues) -> CGSize {
-      { _, _, _ in .zero }
-    }
-  }
-
-  var measureImage: (Image, ProposedViewSize, EnvironmentValues) -> CGSize {
-    get { self[MeasureImageKey.self] }
-    set { self[MeasureImageKey.self] = newValue }
-  }
-}

Sources/TokamakCore/Fiber/Layout/ContainedZLayout.swift

@@ -1,136 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/20/22.
-//
-
-import Foundation
-
-/// The cache for a `ContainedZLayout`.
-@_spi(TokamakCore)
-public struct ContainedZLayoutCache {
-  /// The result of `dimensions(in:)` for the primary subview.
-  var primaryDimensions: ViewDimensions?
-}
-
-/// A layout that fits secondary subviews to the size of a primary subview.
-///
-/// Used to implement `_BackgroundLayout` and `_OverlayLayout`.
-@_spi(TokamakCore)
-public protocol ContainedZLayout: Layout where Cache == ContainedZLayoutCache {
-  var alignment: Alignment { get }
-  /// An accessor for the primary subview from a `LayoutSubviews` collection.
-  static var primarySubview: KeyPath<LayoutSubviews, LayoutSubview?> { get }
-}
-
-@_spi(TokamakCore)
-public extension ContainedZLayout {
-  func makeCache(subviews: Subviews) -> Cache {
-    .init()
-  }
-
-  func spacing(subviews: LayoutSubviews, cache: inout Cache) -> ViewSpacing {
-    subviews[keyPath: Self.primarySubview]?.spacing ?? .init()
-  }
-
-  func sizeThatFits(
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) -> CGSize {
-    // Assume the dimensions of the primary subview.
-    cache.primaryDimensions = subviews[keyPath: Self.primarySubview]?.dimensions(in: proposal)
-    return .init(
-      width: cache.primaryDimensions?.width ?? .zero,
-      height: cache.primaryDimensions?.height ?? .zero
-    )
-  }
-
-  func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) {
-    let proposal = ProposedViewSize(bounds.size)
-
-    // Place the foreground at the origin.
-    subviews[keyPath: Self.primarySubview]?.place(at: bounds.origin, proposal: proposal)
-
-    let backgroundSubviews = subviews[keyPath: Self.primarySubview] == subviews.first
-      ? subviews.dropFirst(1)
-      : subviews.dropLast(1)
-
-    /// The `ViewDimensions` of the subview with the greatest `width`, used to follow `alignment`.
-    var widest: ViewDimensions?
-    /// The `ViewDimensions` of the subview with the greatest `height`.
-    var tallest: ViewDimensions?
-
-    let dimensions = backgroundSubviews.map { subview -> ViewDimensions in
-      let dimensions = subview.dimensions(in: proposal)
-      if dimensions.width > (widest?.width ?? .zero) {
-        widest = dimensions
-      }
-      if dimensions.height > (tallest?.height ?? .zero) {
-        tallest = dimensions
-      }
-      return dimensions
-    }
-
-    /// The alignment guide values of the primary subview.
-    let primaryOffset = CGSize(
-      width: cache.primaryDimensions?[alignment.horizontal] ?? .zero,
-      height: cache.primaryDimensions?[alignment.vertical] ?? .zero
-    )
-    /// The alignment guide values of the secondary subviews (background/overlay).
-    /// Uses the widest/tallest element to get the full extents.
-    let secondaryOffset = CGSize(
-      width: widest?[alignment.horizontal] ?? .zero,
-      height: tallest?[alignment.vertical] ?? .zero
-    )
-    /// The center offset of the secondary subviews.
-    let secondaryCenter = CGSize(
-      width: widest?[HorizontalAlignment.center] ?? .zero,
-      height: tallest?[VerticalAlignment.center] ?? .zero
-    )
-    /// The origin of the secondary subviews with alignment.
-    let secondaryOrigin = CGPoint(
-      x: bounds.minX + primaryOffset.width - secondaryOffset.width + secondaryCenter.width,
-      y: bounds.minY + primaryOffset.height - secondaryOffset.height + secondaryCenter.height
-    )
-    for (index, subview) in backgroundSubviews.enumerated() {
-      // Background elements are centered between each other, but placed with `alignment`
-      // all together on the foreground.
-      subview.place(
-        at: .init(
-          x: secondaryOrigin.x - dimensions[index][HorizontalAlignment.center],
-          y: secondaryOrigin.y - dimensions[index][VerticalAlignment.center]
-        ),
-        proposal: proposal
-      )
-    }
-  }
-}
-
-/// Expects the primary subview to be last.
-@_spi(TokamakCore)
-extension _BackgroundLayout: ContainedZLayout {
-  public static var primarySubview: KeyPath<LayoutSubviews, LayoutSubview?> { \.last }
-}
-
-/// Expects the primary subview to be the first.
-@_spi(TokamakCore)
-extension _OverlayLayout: ContainedZLayout {
-  public static var primarySubview: KeyPath<LayoutSubviews, LayoutSubview?> { \.first }
-}

Sources/TokamakCore/Fiber/Layout/Layout.swift

@@ -1,477 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/16/22.
-//
-
-import Foundation
-
-/// Erase a `Layout` conformance to an `AnyLayout`.
-///
-/// This could potentially be removed in Swift 5.7 in favor of `any Layout`.
-public protocol _AnyLayout {
-  func _erased() -> AnyLayout
-}
-
-/// A type that participates in the layout pass.
-///
-/// Any `View` or `Scene` that implements this protocol will be used to compute layout in
-/// a `FiberRenderer` with `useDynamicLayout` set to `true`.
-public protocol Layout: Animatable, _AnyLayout {
-  static var layoutProperties: LayoutProperties { get }
-
-  associatedtype Cache = ()
-
-  /// Proxies for the children of this container.
-  typealias Subviews = LayoutSubviews
-
-  /// Create a fresh `Cache`. Use it to store complex operations,
-  /// or to pass data between `sizeThatFits` and `placeSubviews`.
-  ///
-  /// - Note: There are no guarantees about when the cache will be recreated,
-  /// and the behavior could change at any time.
-  func makeCache(subviews: Self.Subviews) -> Self.Cache
-
-  /// Update the existing `Cache` before each layout pass.
-  func updateCache(_ cache: inout Self.Cache, subviews: Self.Subviews)
-
-  /// The preferred spacing for this `View` and its subviews.
-  func spacing(subviews: Self.Subviews, cache: inout Self.Cache) -> ViewSpacing
-
-  /// Request a size to contain the subviews and fit within `proposal`.
-  /// If you provide a size that does not fit within `proposal`, the parent will still respect it.
-  func sizeThatFits(
-    proposal: ProposedViewSize,
-    subviews: Self.Subviews,
-    cache: inout Self.Cache
-  ) -> CGSize
-
-  /// Place each subview with `LayoutSubview.place(at:anchor:proposal:)`.
-  ///
-  /// - Note: The bounds are not necessarily at `(0, 0)`, so use `bounds.minX` and `bounds.minY`
-  /// to correctly position relative to the container.
-  func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Self.Subviews,
-    cache: inout Self.Cache
-  )
-
-  /// Override the value of a `HorizontalAlignment` value.
-  func explicitAlignment(
-    of guide: HorizontalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Self.Subviews,
-    cache: inout Self.Cache
-  ) -> CGFloat?
-
-  /// Override the value of a `VerticalAlignment` value.
-  func explicitAlignment(
-    of guide: VerticalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Self.Subviews,
-    cache: inout Self.Cache
-  ) -> CGFloat?
-}
-
-public extension Layout {
-  func _erased() -> AnyLayout {
-    .init(self)
-  }
-}
-
-public extension Layout where Self.Cache == () {
-  func makeCache(subviews: Self.Subviews) -> Self.Cache {
-    ()
-  }
-}
-
-public extension Layout {
-  static var layoutProperties: LayoutProperties {
-    .init()
-  }
-
-  func updateCache(_ cache: inout Self.Cache, subviews: Self.Subviews) {
-    cache = makeCache(subviews: subviews)
-  }
-
-  func spacing(subviews: Self.Subviews, cache: inout Self.Cache) -> ViewSpacing {
-    subviews.reduce(
-      into: subviews.first.map {
-        .init(
-          viewType: $0.spacing.viewType,
-          top: { _ in 0 },
-          leading: { _ in 0 },
-          bottom: { _ in 0 },
-          trailing: { _ in 0 }
-        )
-      } ?? .zero
-    ) { $0.formUnion($1.spacing) }
-  }
-
-  func explicitAlignment(
-    of guide: HorizontalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Self.Subviews,
-    cache: inout Self.Cache
-  ) -> CGFloat? {
-    nil
-  }
-
-  func explicitAlignment(
-    of guide: VerticalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Self.Subviews,
-    cache: inout Self.Cache
-  ) -> CGFloat? {
-    nil
-  }
-}
-
-public extension Layout {
-  /// Render `content` using `self` as the layout container.
-  func callAsFunction<V>(@ViewBuilder _ content: () -> V) -> some View where V: View {
-    LayoutView(layout: self, content: content())
-  }
-}
-
-/// A `View` that renders its children with a `Layout`.
-@_spi(TokamakCore)
-public struct LayoutView<L: Layout, Content: View>: View, Layout {
-  let layout: L
-  let content: Content
-
-  public typealias Cache = L.Cache
-
-  public func makeCache(subviews: Subviews) -> L.Cache {
-    layout.makeCache(subviews: subviews)
-  }
-
-  public func updateCache(_ cache: inout L.Cache, subviews: Subviews) {
-    layout.updateCache(&cache, subviews: subviews)
-  }
-
-  public func spacing(subviews: Subviews, cache: inout L.Cache) -> ViewSpacing {
-    layout.spacing(subviews: subviews, cache: &cache)
-  }
-
-  public func sizeThatFits(
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) -> CGSize {
-    layout.sizeThatFits(proposal: proposal, subviews: subviews, cache: &cache)
-  }
-
-  public func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) {
-    layout.placeSubviews(in: bounds, proposal: proposal, subviews: subviews, cache: &cache)
-  }
-
-  public func explicitAlignment(
-    of guide: HorizontalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout L.Cache
-  ) -> CGFloat? {
-    layout.explicitAlignment(
-      of: guide, in: bounds, proposal: proposal, subviews: subviews, cache: &cache
-    )
-  }
-
-  public func explicitAlignment(
-    of guide: VerticalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout L.Cache
-  ) -> CGFloat? {
-    layout.explicitAlignment(
-      of: guide, in: bounds, proposal: proposal, subviews: subviews, cache: &cache
-    )
-  }
-
-  public var body: some View {
-    content
-  }
-}
-
-/// A default `Layout` that fits to the first subview and places its children at its origin.
-struct DefaultLayout: Layout {
-  /// An erased `DefaultLayout` that is shared between all views.
-  static let shared: AnyLayout = .init(Self())
-
-  func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) -> CGSize {
-    let size = subviews.first?.sizeThatFits(proposal) ?? .zero
-    return size
-  }
-
-  func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout ()
-  ) {
-    for subview in subviews {
-      subview.place(at: bounds.origin, proposal: proposal)
-    }
-  }
-}
-
-/// Describes a container for an erased `Layout` type.
-///
-/// Matches the `Layout` protocol with `Cache` erased to `Any`.
-@usableFromInline
-protocol AnyLayoutBox: AnyObject {
-  var layoutProperties: LayoutProperties { get }
-
-  typealias Subviews = LayoutSubviews
-  typealias Cache = Any
-
-  func makeCache(subviews: Self.Subviews) -> Self.Cache
-
-  func updateCache(_ cache: inout Self.Cache, subviews: Self.Subviews)
-
-  func spacing(subviews: Self.Subviews, cache: inout Self.Cache) -> ViewSpacing
-
-  func sizeThatFits(
-    proposal: ProposedViewSize,
-    subviews: Self.Subviews,
-    cache: inout Self.Cache
-  ) -> CGSize
-
-  func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Self.Subviews,
-    cache: inout Self.Cache
-  )
-
-  func explicitAlignment(
-    of guide: HorizontalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Self.Subviews,
-    cache: inout Self.Cache
-  ) -> CGFloat?
-
-  func explicitAlignment(
-    of guide: VerticalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Self.Subviews,
-    cache: inout Self.Cache
-  ) -> CGFloat?
-
-  var animatableData: _AnyAnimatableData { get set }
-}
-
-final class ConcreteLayoutBox<L: Layout>: AnyLayoutBox {
-  var base: L
-
-  init(_ base: L) {
-    self.base = base
-  }
-
-  var layoutProperties: LayoutProperties { L.layoutProperties }
-
-  func makeCache(subviews: Subviews) -> Cache {
-    base.makeCache(subviews: subviews)
-  }
-
-  private func typedCache<R>(
-    subviews: Subviews,
-    erasedCache: inout Cache,
-    _ action: (inout L.Cache) -> R
-  ) -> R {
-    var typedCache = erasedCache as? L.Cache ?? base.makeCache(subviews: subviews)
-    defer { erasedCache = typedCache }
-    return action(&typedCache)
-  }
-
-  func updateCache(_ cache: inout Cache, subviews: Subviews) {
-    typedCache(subviews: subviews, erasedCache: &cache) {
-      base.updateCache(&$0, subviews: subviews)
-    }
-  }
-
-  func spacing(subviews: Subviews, cache: inout Cache) -> ViewSpacing {
-    typedCache(subviews: subviews, erasedCache: &cache) {
-      base.spacing(subviews: subviews, cache: &$0)
-    }
-  }
-
-  func sizeThatFits(
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) -> CGSize {
-    typedCache(subviews: subviews, erasedCache: &cache) {
-      base.sizeThatFits(proposal: proposal, subviews: subviews, cache: &$0)
-    }
-  }
-
-  func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) {
-    typedCache(subviews: subviews, erasedCache: &cache) {
-      base.placeSubviews(in: bounds, proposal: proposal, subviews: subviews, cache: &$0)
-    }
-  }
-
-  func explicitAlignment(
-    of guide: HorizontalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) -> CGFloat? {
-    typedCache(subviews: subviews, erasedCache: &cache) {
-      base.explicitAlignment(
-        of: guide,
-        in: bounds,
-        proposal: proposal,
-        subviews: subviews,
-        cache: &$0
-      )
-    }
-  }
-
-  func explicitAlignment(
-    of guide: VerticalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) -> CGFloat? {
-    typedCache(subviews: subviews, erasedCache: &cache) {
-      base.explicitAlignment(
-        of: guide,
-        in: bounds,
-        proposal: proposal,
-        subviews: subviews,
-        cache: &$0
-      )
-    }
-  }
-
-  var animatableData: _AnyAnimatableData {
-    get {
-      .init(base.animatableData)
-    }
-    set {
-      guard let newData = newValue.value as? L.AnimatableData else { return }
-      base.animatableData = newData
-    }
-  }
-}
-
-@frozen
-public struct AnyLayout: Layout {
-  var storage: AnyLayoutBox
-
-  public init<L>(_ layout: L) where L: Layout {
-    storage = ConcreteLayoutBox(layout)
-  }
-
-  public struct Cache {
-    var erasedCache: Any
-  }
-
-  public func makeCache(subviews: AnyLayout.Subviews) -> AnyLayout.Cache {
-    .init(erasedCache: storage.makeCache(subviews: subviews))
-  }
-
-  public func updateCache(_ cache: inout AnyLayout.Cache, subviews: AnyLayout.Subviews) {
-    storage.updateCache(&cache.erasedCache, subviews: subviews)
-  }
-
-  public func spacing(subviews: AnyLayout.Subviews, cache: inout AnyLayout.Cache) -> ViewSpacing {
-    storage.spacing(subviews: subviews, cache: &cache.erasedCache)
-  }
-
-  public func sizeThatFits(
-    proposal: ProposedViewSize,
-    subviews: AnyLayout.Subviews,
-    cache: inout AnyLayout.Cache
-  ) -> CGSize {
-    storage.sizeThatFits(proposal: proposal, subviews: subviews, cache: &cache.erasedCache)
-  }
-
-  public func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: AnyLayout.Subviews,
-    cache: inout AnyLayout.Cache
-  ) {
-    storage.placeSubviews(
-      in: bounds,
-      proposal: proposal,
-      subviews: subviews,
-      cache: &cache.erasedCache
-    )
-  }
-
-  public func explicitAlignment(
-    of guide: HorizontalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: AnyLayout.Subviews,
-    cache: inout AnyLayout.Cache
-  ) -> CGFloat? {
-    storage.explicitAlignment(
-      of: guide,
-      in: bounds,
-      proposal: proposal,
-      subviews: subviews,
-      cache: &cache.erasedCache
-    )
-  }
-
-  public func explicitAlignment(
-    of guide: VerticalAlignment,
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: AnyLayout.Subviews,
-    cache: inout AnyLayout.Cache
-  ) -> CGFloat? {
-    storage.explicitAlignment(
-      of: guide, in: bounds,
-      proposal: proposal,
-      subviews: subviews,
-      cache: &cache.erasedCache
-    )
-  }
-
-  public var animatableData: _AnyAnimatableData {
-    get {
-      _AnyAnimatableData(storage.animatableData)
-    }
-    set {
-      storage.animatableData = newValue
-    }
-  }
-}

Sources/TokamakCore/Fiber/Layout/LayoutPriority.swift

@@ -1,31 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/22/22.
-//
-
-import Foundation
-
-@usableFromInline
-enum LayoutPriorityTraitKey: _ViewTraitKey {
-  @inlinable
-  static var defaultValue: Double { 0 }
-}
-
-public extension View {
-  @inlinable
-  func layoutPriority(_ value: Double) -> some View {
-    _trait(LayoutPriorityTraitKey.self, value)
-  }
-}

Sources/TokamakCore/Fiber/Layout/LayoutProperties.swift

@@ -1,25 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/20/22.
-//
-
-/// Metadata about a `Layout`.
-public struct LayoutProperties {
-  public var stackOrientation: Axis?
-
-  public init() {
-    stackOrientation = nil
-  }
-}

Sources/TokamakCore/Fiber/Layout/LayoutSubviews.swift

@@ -1,252 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/20/22.
-//
-
-import Foundation
-
-/// A collection of `LayoutSubview` proxies.
-public struct LayoutSubviews: Equatable, RandomAccessCollection {
-  public var layoutDirection: LayoutDirection
-  var storage: [LayoutSubview]
-
-  init(layoutDirection: LayoutDirection, storage: [LayoutSubview]) {
-    self.layoutDirection = layoutDirection
-    self.storage = storage
-  }
-
-  init<R: FiberRenderer>(_ node: FiberReconciler<R>.Fiber) {
-    self.init(
-      layoutDirection: node.outputs.environment.environment.layoutDirection,
-      storage: []
-    )
-  }
-
-  public typealias SubSequence = LayoutSubviews
-  public typealias Element = LayoutSubview
-  public typealias Index = Int
-  public typealias Indices = Range<LayoutSubviews.Index>
-  public typealias Iterator = IndexingIterator<LayoutSubviews>
-
-  public var startIndex: Int {
-    storage.startIndex
-  }
-
-  public var endIndex: Int {
-    storage.endIndex
-  }
-
-  public subscript(index: Int) -> LayoutSubviews.Element {
-    storage[index]
-  }
-
-  public subscript(bounds: Range<Int>) -> LayoutSubviews {
-    .init(layoutDirection: layoutDirection, storage: .init(storage[bounds]))
-  }
-
-  public subscript<S>(indices: S) -> LayoutSubviews where S: Sequence, S.Element == Int {
-    .init(
-      layoutDirection: layoutDirection,
-      storage: storage.enumerated()
-        .filter { indices.contains($0.offset) }
-        .map(\.element)
-    )
-  }
-}
-
-/// A proxy representing a child of a `Layout`.
-///
-/// Access size requests, alignment guide values, spacing preferences, and any layout values using
-/// this proxy.
-///
-/// `Layout` types are expected to call `place(at:anchor:proposal:)` on all subviews.
-/// If `place(at:anchor:proposal:)` is not called, the center will be used as its position.
-public struct LayoutSubview: Equatable {
-  private let id: ObjectIdentifier
-  private let storage: AnyStorage
-
-  /// A protocol used to erase `Storage<R>`.
-  private class AnyStorage {
-    let traits: _ViewTraitStore?
-
-    init(traits: _ViewTraitStore?) {
-      self.traits = traits
-    }
-
-    func sizeThatFits(_ proposal: ProposedViewSize) -> CGSize {
-      fatalError("Implement \(#function) in subclass")
-    }
-
-    func dimensions(_ sizeThatFits: CGSize) -> ViewDimensions {
-      fatalError("Implement \(#function) in subclass")
-    }
-
-    func place(
-      _ proposal: ProposedViewSize,
-      _ dimensions: ViewDimensions,
-      _ position: CGPoint,
-      _ anchor: UnitPoint
-    ) {
-      fatalError("Implement \(#function) in subclass")
-    }
-
-    func spacing() -> ViewSpacing {
-      fatalError("Implement \(#function) in subclass")
-    }
-  }
-
-  /// The backing storage for a `LayoutSubview`. This contains the underlying implementations for
-  /// methods accessing the `fiber`, `element`, and `cache` this subview represents.
-  private final class Storage<R: FiberRenderer>: AnyStorage {
-    weak var fiber: FiberReconciler<R>.Fiber?
-    weak var element: R.ElementType?
-    unowned var caches: FiberReconciler<R>.Caches
-
-    init(
-      traits: _ViewTraitStore?,
-      fiber: FiberReconciler<R>.Fiber?,
-      element: R.ElementType?,
-      caches: FiberReconciler<R>.Caches
-    ) {
-      self.fiber = fiber
-      self.element = element
-      self.caches = caches
-      super.init(traits: traits)
-    }
-
-    override func sizeThatFits(_ proposal: ProposedViewSize) -> CGSize {
-      guard let fiber = fiber else { return .zero }
-      let request = FiberReconciler<R>.Caches.LayoutCache.SizeThatFitsRequest(proposal)
-      return caches.updateLayoutCache(for: fiber) { cache in
-        guard let layout = fiber.layout else { return .zero }
-        if let size = cache.sizeThatFits[request] {
-          return size
-        } else {
-          let size = layout.sizeThatFits(
-            proposal: proposal,
-            subviews: caches.layoutSubviews(for: fiber),
-            cache: &cache.cache
-          )
-          cache.sizeThatFits[request] = size
-          if let alternate = fiber.alternate {
-            caches.updateLayoutCache(for: alternate) { alternateCache in
-              alternateCache.cache = cache.cache
-              alternateCache.sizeThatFits[request] = size
-            }
-          }
-          return size
-        }
-      } ?? .zero
-    }
-
-    override func dimensions(_ sizeThatFits: CGSize) -> ViewDimensions {
-      // TODO: Add `alignmentGuide` modifier and pass into `ViewDimensions`
-      ViewDimensions(size: sizeThatFits, alignmentGuides: [:])
-    }
-
-    override func place(
-      _ proposal: ProposedViewSize,
-      _ dimensions: ViewDimensions,
-      _ position: CGPoint,
-      _ anchor: UnitPoint
-    ) {
-      guard let fiber = fiber, let element = element else { return }
-      let geometry = ViewGeometry(
-        // Shift to the anchor point in the parent's coordinate space.
-        origin: .init(origin: .init(
-          x: position.x - (dimensions.width * anchor.x),
-          y: position.y - (dimensions.height * anchor.y)
-        )),
-        dimensions: dimensions,
-        proposal: proposal
-      )
-      // Push a layout mutation if needed.
-      if geometry != fiber.alternate?.geometry {
-        caches.mutations.append(.layout(element: element, geometry: geometry))
-      }
-      // Update ours and our alternate's geometry
-      fiber.geometry = geometry
-      fiber.alternate?.geometry = geometry
-    }
-
-    override func spacing() -> ViewSpacing {
-      guard let fiber = fiber else { return .init() }
-
-      return caches.updateLayoutCache(for: fiber) { cache in
-        fiber.layout?.spacing(
-          subviews: caches.layoutSubviews(for: fiber),
-          cache: &cache.cache
-        ) ?? .zero
-      } ?? .zero
-    }
-  }
-
-  init<R: FiberRenderer>(
-    id: ObjectIdentifier,
-    traits: _ViewTraitStore?,
-    fiber: FiberReconciler<R>.Fiber,
-    element: R.ElementType,
-    caches: FiberReconciler<R>.Caches
-  ) {
-    self.id = id
-    storage = Storage(
-      traits: traits,
-      fiber: fiber,
-      element: element,
-      caches: caches
-    )
-  }
-
-  public func _trait<K>(key: K.Type) -> K.Value where K: _ViewTraitKey {
-    storage.traits?.value(forKey: key) ?? K.defaultValue
-  }
-
-  public subscript<K>(key: K.Type) -> K.Value where K: LayoutValueKey {
-    _trait(key: _LayoutTrait<K>.self)
-  }
-
-  public var priority: Double {
-    _trait(key: LayoutPriorityTraitKey.self)
-  }
-
-  public func sizeThatFits(_ proposal: ProposedViewSize) -> CGSize {
-    storage.sizeThatFits(proposal)
-  }
-
-  public func dimensions(in proposal: ProposedViewSize) -> ViewDimensions {
-    storage.dimensions(sizeThatFits(proposal))
-  }
-
-  public var spacing: ViewSpacing {
-    storage.spacing()
-  }
-
-  public func place(
-    at position: CGPoint,
-    anchor: UnitPoint = .topLeading,
-    proposal: ProposedViewSize
-  ) {
-    storage.place(
-      proposal,
-      dimensions(in: proposal),
-      position,
-      anchor
-    )
-  }
-
-  public static func == (lhs: LayoutSubview, rhs: LayoutSubview) -> Bool {
-    lhs.storage === rhs.storage
-  }
-}

Sources/TokamakCore/Fiber/Layout/LayoutValueKey.swift

@@ -1,36 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/20/22.
-//
-
-/// A key that stores a value that can be accessed via a `LayoutSubview`.
-public protocol LayoutValueKey {
-  associatedtype Value
-  static var defaultValue: Self.Value { get }
-}
-
-public extension View {
-  @inlinable
-  func layoutValue<K>(key: K.Type, value: K.Value) -> some View where K: LayoutValueKey {
-    // LayoutValueKey uses trait keys under the hood.
-    _trait(_LayoutTrait<K>.self, value)
-  }
-}
-
-public struct _LayoutTrait<K>: _ViewTraitKey where K: LayoutValueKey {
-  public static var defaultValue: K.Value {
-    K.defaultValue
-  }
-}

Sources/TokamakCore/Fiber/Layout/PaddingLayout+Layout.swift

@@ -1,84 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 5/28/22.
-//
-
-import Foundation
-
-private extension EdgeInsets {
-  init(applying edges: Edge.Set, to insets: EdgeInsets) {
-    self.init(
-      top: edges.contains(.top) ? insets.top : 0,
-      leading: edges.contains(.leading) ? insets.leading : 0,
-      bottom: edges.contains(.bottom) ? insets.bottom : 0,
-      trailing: edges.contains(.trailing) ? insets.trailing : 0
-    )
-  }
-}
-
-private struct PaddingLayout: Layout {
-  let edges: Edge.Set
-  let insets: EdgeInsets?
-
-  func spacing(subviews: Subviews, cache: inout ()) -> ViewSpacing {
-    .init()
-  }
-
-  public func sizeThatFits(
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout ()
-  ) -> CGSize {
-    let proposal = proposal.replacingUnspecifiedDimensions()
-    let insets = EdgeInsets(applying: edges, to: insets ?? .init(_all: 10))
-    let subviewSize = subviews.first?.sizeThatFits(
-      .init(
-        width: proposal.width - insets.leading - insets.trailing,
-        height: proposal.height - insets.top - insets.bottom
-      )
-    ) ?? .zero
-    return .init(
-      width: subviewSize.width + insets.leading + insets.trailing,
-      height: subviewSize.height + insets.top + insets.bottom
-    )
-  }
-
-  public func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout ()
-  ) {
-    let insets = EdgeInsets(applying: edges, to: insets ?? .init(_all: 10))
-    let proposal = proposal.replacingUnspecifiedDimensions()
-    for subview in subviews {
-      subview.place(
-        at: .init(x: bounds.minX + insets.leading, y: bounds.minY + insets.top),
-        proposal: .init(
-          width: proposal.width - insets.leading - insets.trailing,
-          height: proposal.height - insets.top - insets.bottom
-        )
-      )
-    }
-  }
-}
-
-public extension _PaddingLayout {
-  func _visitChildren<V>(_ visitor: V, content: Content) where V: ViewVisitor {
-    visitor.visit(PaddingLayout(edges: edges, insets: insets).callAsFunction {
-      content
-    })
-  }
-}

Sources/TokamakCore/Fiber/Layout/ProposedViewSize.swift

@@ -1,44 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/20/22.
-//
-
-import Foundation
-
-@frozen
-public struct ProposedViewSize: Equatable {
-  public var width: CGFloat?
-  public var height: CGFloat?
-  public static let zero: ProposedViewSize = .init(width: 0, height: 0)
-  public static let unspecified: ProposedViewSize = .init(width: nil, height: nil)
-  public static let infinity: ProposedViewSize = .init(width: .infinity, height: .infinity)
-  @inlinable
-  public init(width: CGFloat?, height: CGFloat?) {
-    (self.width, self.height) = (width, height)
-  }
-
-  @inlinable
-  public init(_ size: CGSize) {
-    self.init(width: size.width, height: size.height)
-  }
-
-  @inlinable
-  public func replacingUnspecifiedDimensions(by size: CGSize = CGSize(
-    width: 10,
-    height: 10
-  )) -> CGSize {
-    CGSize(width: width ?? size.width, height: height ?? size.height)
-  }
-}

Sources/TokamakCore/Fiber/Layout/StackLayout.swift

@@ -1,268 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 5/24/22.
-//
-
-import Foundation
-
-private extension ViewDimensions {
-  /// Access the guide value of an `Alignment` for a particular `Axis`.
-  subscript(alignment alignment: Alignment, in axis: Axis) -> CGFloat {
-    switch axis {
-    case .horizontal: return self[alignment.vertical]
-    case .vertical: return self[alignment.horizontal]
-    }
-  }
-}
-
-/// The `Layout.Cache` for `StackLayout` conforming types.
-@_spi(TokamakCore)
-public struct StackLayoutCache {
-  /// The widest/tallest (depending on the `axis`) subview.
-  /// Used to place subviews along the `alignment`.
-  var maxSubview: ViewDimensions?
-
-  /// The ideal size for each subview as computed in `sizeThatFits`.
-  var idealSizes = [CGSize]()
-}
-
-/// An internal structure used to store layout information about
-/// `LayoutSubview`s of a `StackLayout` that will later be sorted
-private struct MeasuredSubview {
-  let view: LayoutSubview
-  let index: Int
-  let min: CGSize
-  let max: CGSize
-  let infiniteMainAxis: Bool
-  let spacing: CGFloat
-}
-
-/// The protocol all built-in stacks conform to.
-/// Provides a shared implementation for stack layout logic.
-@_spi(TokamakCore)
-public protocol StackLayout: Layout where Cache == StackLayoutCache {
-  /// The direction of this stack. `vertical` for `VStack`, `horizontal` for `HStack`.
-  static var orientation: Axis { get }
-
-  /// The full `Alignment` with an ignored value for the main axis.
-  var _alignment: Alignment { get }
-
-  var spacing: CGFloat? { get }
-}
-
-@_spi(TokamakCore)
-public extension StackLayout {
-  static var layoutProperties: LayoutProperties {
-    var properties = LayoutProperties()
-    properties.stackOrientation = Self.orientation
-    return properties
-  }
-
-  /// The `CGSize` component for the current `axis`.
-  ///
-  /// A `vertical` axis will return `height`.
-  /// A `horizontal` axis will return `width`.
-  static var mainAxis: WritableKeyPath<CGSize, CGFloat> {
-    switch Self.orientation {
-    case .vertical: return \.height
-    case .horizontal: return \.width
-    }
-  }
-
-  /// The `CGSize` component for the axis opposite `axis`.
-  ///
-  /// A `vertical` axis will return `width`.
-  /// A `horizontal` axis will return `height`.
-  static var crossAxis: WritableKeyPath<CGSize, CGFloat> {
-    switch Self.orientation {
-    case .vertical: return \.width
-    case .horizontal: return \.height
-    }
-  }
-
-  func makeCache(subviews: Subviews) -> Cache {
-    // Ensure we have enough space in `idealSizes` for each subview.
-    .init(maxSubview: nil, idealSizes: Array(repeating: .zero, count: subviews.count))
-  }
-
-  func updateCache(_ cache: inout Cache, subviews: Subviews) {
-    cache.maxSubview = nil
-    // Ensure we have enough space in `idealSizes` for each subview.
-    cache.idealSizes = Array(repeating: .zero, count: subviews.count)
-  }
-
-  func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout Cache) -> CGSize {
-    let proposal = proposal.replacingUnspecifiedDimensions()
-
-    /// The minimum size of each `View` on the main axis.
-    var minSize = CGFloat.zero
-
-    /// The aggregate `ViewSpacing` distances.
-    var totalSpacing = CGFloat.zero
-
-    /// The number of `View`s with a given priority.
-    var priorityCount = [Double: Int]()
-
-    /// The aggregate minimum size of each `View` with a given priority.
-    var prioritySize = [Double: CGFloat]()
-    let measuredSubviews = subviews.enumerated().map { index, view -> MeasuredSubview in
-      priorityCount[view.priority, default: 0] += 1
-
-      var minProposal = CGSize(width: CGFloat.infinity, height: CGFloat.infinity)
-      minProposal[keyPath: Self.crossAxis] = proposal[keyPath: Self.crossAxis]
-      minProposal[keyPath: Self.mainAxis] = 0
-      /// The minimum size for this subview along the `mainAxis`.
-      /// Uses `dimensions(in:)` to collect the alignment guides for use in `placeSubviews`.
-      let min = view.dimensions(in: .init(minProposal))
-
-      // Aggregate the minimum size of the stack for the combined subviews.
-      minSize += min.size[keyPath: Self.mainAxis]
-
-      // Aggregate the minimum size of this priority to divvy up space later.
-      prioritySize[view.priority, default: 0] += min.size[keyPath: Self.mainAxis]
-
-      var maxProposal = CGSize(width: CGFloat.infinity, height: CGFloat.infinity)
-      maxProposal[keyPath: Self.crossAxis] = minProposal[keyPath: Self.crossAxis]
-      /// The maximum size for this subview along the `mainAxis`.
-      let max = view.sizeThatFits(.init(maxProposal))
-
-      /// The spacing around this `View` and its previous (if it is not first).
-      let spacing: CGFloat
-      if subviews.indices.contains(index - 1) {
-        if let overrideSpacing = self.spacing {
-          spacing = overrideSpacing
-        } else {
-          spacing = subviews[index - 1].spacing.distance(to: view.spacing, along: Self.orientation)
-        }
-      } else {
-        spacing = .zero
-      }
-      // Aggregate all spacing values.
-      totalSpacing += spacing
-
-      // If this `View` is the widest, save it to the cache for access in `placeSubviews`.
-      if min.size[keyPath: Self.crossAxis] > cache.maxSubview?.size[keyPath: Self.crossAxis]
-        ?? .zero
-      {
-        cache.maxSubview = min
-      }
-
-      return MeasuredSubview(
-        view: view,
-        index: index,
-        min: min.size,
-        max: max,
-        infiniteMainAxis: max[keyPath: Self.mainAxis] == .infinity,
-        spacing: spacing
-      )
-    }
-
-    // Calculate ideal sizes for each View based on their min/max sizes and the space available.
-    var available = proposal[keyPath: Self.mainAxis] - minSize - totalSpacing
-    // The final resulting size.
-    var size = CGSize.zero
-    size[keyPath: Self.crossAxis] = cache.maxSubview?.size[keyPath: Self.crossAxis] ?? .zero
-    for subview in measuredSubviews.sorted(by: {
-      // Sort by priority descending.
-      if $0.view.priority == $1.view.priority {
-        // If the priorities match, allow non-flexible `View`s to size first.
-        return $1.infiniteMainAxis && !$0.infiniteMainAxis
-      } else {
-        return $0.view.priority > $1.view.priority
-      }
-    }) {
-      // The amount of space available to `View`s with this priority value.
-      let priorityAvailable = available + prioritySize[subview.view.priority, default: 0]
-      // The number of `View`s with this priority value remaining as a `CGFloat`.
-      let priorityRemaining = CGFloat(priorityCount[subview.view.priority, default: 1])
-      // Propose the full `crossAxis`, but only the remaining `mainAxis`.
-      // Divvy up the available space between each remaining `View` with this priority value.
-      var divviedSize = proposal
-      divviedSize[keyPath: Self.mainAxis] = priorityAvailable / priorityRemaining
-      let idealSize = subview.view.sizeThatFits(.init(divviedSize))
-      cache.idealSizes[subview.index] = idealSize
-      size[keyPath: Self.mainAxis] += idealSize[keyPath: Self.mainAxis] + subview.spacing
-      // Remove our `idealSize` from the `available` space.
-      available -= idealSize[keyPath: Self.mainAxis]
-      // Decrement the number of `View`s left with this priority so space can be evenly divided
-      // between the remaining `View`s.
-      priorityCount[subview.view.priority, default: 1] -= 1
-    }
-    return size
-  }
-
-  func spacing(subviews: Subviews, cache: inout Cache) -> ViewSpacing {
-    subviews.reduce(into: .zero) { $0.formUnion($1.spacing) }
-  }
-
-  func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) {
-    // The current progress along the `mainAxis`.
-    var position = CGFloat.zero
-    // The offset of the `_alignment` in the `maxSubview`,
-    // used as the reference point for alignments along this axis.
-    let alignmentOffset = cache.maxSubview?[alignment: _alignment, in: Self.orientation] ?? .zero
-    for (index, view) in subviews.enumerated() {
-      // Add a gap for the spacing distance from the previous subview to this one.
-      let spacing: CGFloat
-      if subviews.indices.contains(index - 1) {
-        if let overrideSpacing = self.spacing {
-          spacing = overrideSpacing
-        } else {
-          spacing = subviews[index - 1].spacing.distance(to: view.spacing, along: Self.orientation)
-        }
-      } else {
-        spacing = .zero
-      }
-      position += spacing
-
-      let proposal = ProposedViewSize(cache.idealSizes[index])
-      let size = view.dimensions(in: proposal)
-
-      // Offset the placement along the `crossAxis` to align with the
-      // `alignment` of the `maxSubview`.
-      var placement = CGSize(width: bounds.minX, height: bounds.minY)
-      placement[keyPath: Self.mainAxis] += position
-      placement[keyPath: Self.crossAxis] += alignmentOffset
-        - size[alignment: _alignment, in: Self.orientation]
-
-      view.place(
-        at: .init(
-          x: placement.width,
-          y: placement.height
-        ),
-        proposal: proposal
-      )
-      // Move further along the stack's `mainAxis`.
-      position += size.size[keyPath: Self.mainAxis]
-    }
-  }
-}
-
-@_spi(TokamakCore)
-extension VStack: StackLayout {
-  public static var orientation: Axis { .vertical }
-  public var _alignment: Alignment { .init(horizontal: alignment, vertical: .center) }
-}
-
-@_spi(TokamakCore)
-extension HStack: StackLayout {
-  public static var orientation: Axis { .horizontal }
-  public var _alignment: Alignment { .init(horizontal: .center, vertical: alignment) }
-}

Sources/TokamakCore/Fiber/Layout/ViewSpacing.swift

@@ -1,105 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/20/22.
-//
-
-import Foundation
-
-/// The preferred spacing around a `View`.
-///
-/// When computing spacing in a custom `Layout`, use `distance(to:along:)`
-/// to find the smallest spacing needed to accommodate the preferences
-/// of the `View`s you are aligning.
-public struct ViewSpacing {
-  /// The `View` type this `ViewSpacing` is for.
-  /// Some `View`s prefer different spacing based on the `View` they are adjacent to.
-  @_spi(TokamakCore)
-  public var viewType: Any.Type?
-
-  private var top: (ViewSpacing) -> CGFloat
-  private var leading: (ViewSpacing) -> CGFloat
-  private var bottom: (ViewSpacing) -> CGFloat
-  private var trailing: (ViewSpacing) -> CGFloat
-
-  public static let zero: ViewSpacing = .init(
-    viewType: nil,
-    top: { _ in 0 },
-    leading: { _ in 0 },
-    bottom: { _ in 0 },
-    trailing: { _ in 0 }
-  )
-
-  /// Create a `ViewSpacing` instance with default values.
-  public init() {
-    self.init(viewType: nil)
-  }
-
-  @_spi(TokamakCore)
-  public static let defaultValue: CGFloat = 8
-
-  @_spi(TokamakCore)
-  public init(
-    viewType: Any.Type?,
-    top: @escaping (ViewSpacing) -> CGFloat = { _ in Self.defaultValue },
-    leading: @escaping (ViewSpacing) -> CGFloat = { _ in Self.defaultValue },
-    bottom: @escaping (ViewSpacing) -> CGFloat = { _ in Self.defaultValue },
-    trailing: @escaping (ViewSpacing) -> CGFloat = { _ in Self.defaultValue }
-  ) {
-    self.viewType = viewType
-    self.top = top
-    self.leading = leading
-    self.bottom = bottom
-    self.trailing = trailing
-  }
-
-  public mutating func formUnion(_ other: ViewSpacing, edges: Edge.Set = .all) {
-    if viewType != other.viewType {
-      viewType = nil
-    }
-    if edges.contains(.top) {
-      let current = top
-      top = { max(current($0), other.top($0)) }
-    }
-    if edges.contains(.leading) {
-      let current = leading
-      leading = { max(current($0), other.leading($0)) }
-    }
-    if edges.contains(.bottom) {
-      let current = bottom
-      bottom = { max(current($0), other.bottom($0)) }
-    }
-    if edges.contains(.trailing) {
-      let current = trailing
-      trailing = { max(current($0), other.trailing($0)) }
-    }
-  }
-
-  public func union(_ other: ViewSpacing, edges: Edge.Set = .all) -> ViewSpacing {
-    var spacing = self
-    spacing.formUnion(other, edges: edges)
-    return spacing
-  }
-
-  /// The smallest spacing that accommodates the preferences of `self` and `next`.
-  public func distance(to next: ViewSpacing, along axis: Axis) -> CGFloat {
-    // Assume `next` comes after `self` either horizontally or vertically.
-    switch axis {
-    case .horizontal:
-      return max(trailing(next), next.leading(self))
-    case .vertical:
-      return max(bottom(next), next.top(self))
-    }
-  }
-}

Sources/TokamakCore/Fiber/Layout/_AspectRatioLayout+Layout.swift

@@ -1,106 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/27/22.
-//
-
-import Foundation
-
-private struct AspectRatioLayout: Layout {
-  let aspectRatio: CGFloat?
-  let contentMode: ContentMode
-
-  func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout ()) -> CGSize {
-    let proposal = proposal.replacingUnspecifiedDimensions()
-    let aspectRatio: CGFloat
-    if let ratio = self.aspectRatio {
-      aspectRatio = ratio
-    } else {
-      let idealSubviewSize = subviews.first?.sizeThatFits(.unspecified) ?? .zero
-      if idealSubviewSize.height == 0 {
-        aspectRatio = 0
-      } else {
-        aspectRatio = idealSubviewSize.width / idealSubviewSize.height
-      }
-    }
-    let maxAxis: Axis
-    switch contentMode {
-    case .fit:
-      if proposal.width == proposal.height {
-        if aspectRatio >= 1 {
-          maxAxis = .vertical
-        } else {
-          maxAxis = .horizontal
-        }
-      } else if proposal.width > proposal.height {
-        maxAxis = .horizontal
-      } else {
-        maxAxis = .vertical
-      }
-    case .fill:
-      if proposal.width == proposal.height {
-        if aspectRatio >= 1 {
-          maxAxis = .horizontal
-        } else {
-          maxAxis = .vertical
-        }
-      } else if proposal.width > proposal.height {
-        maxAxis = .vertical
-      } else {
-        maxAxis = .horizontal
-      }
-    }
-    switch maxAxis {
-    case .horizontal:
-      return .init(
-        width: aspectRatio * proposal.height,
-        height: proposal.height
-      )
-    case .vertical:
-      return .init(
-        width: proposal.width,
-        height: (1 / aspectRatio) * proposal.width
-      )
-    }
-  }
-
-  func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout ()
-  ) {
-    for subview in subviews {
-      subview.place(
-        at: .init(x: bounds.midX, y: bounds.midY),
-        anchor: .center,
-        proposal: .init(bounds.size)
-      )
-    }
-  }
-}
-
-public extension _AspectRatioLayout {
-  func _visitChildren<V>(_ visitor: V, content: Content) where V: ViewVisitor {
-    visitor.visit(
-      AspectRatioLayout(
-        aspectRatio: aspectRatio,
-        contentMode: contentMode
-      )
-      .callAsFunction {
-        content
-      }
-    )
-  }
-}

Sources/TokamakCore/Fiber/Layout/_FlexFrameLayout+Layout.swift

@@ -1,139 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/20/22.
-//
-
-import Foundation
-
-/// A `Layout` container that creates a frame with constraints.
-///
-/// The children are proposed the full proposal given to this container
-/// clamped to the specified minimum and maximum values.
-///
-/// Then the children are placed with `alignment` in the container.
-private struct FlexFrameLayout: Layout {
-  let minWidth: CGFloat?
-  let idealWidth: CGFloat?
-  let maxWidth: CGFloat?
-  let minHeight: CGFloat?
-  let idealHeight: CGFloat?
-  let maxHeight: CGFloat?
-  let alignment: Alignment
-
-  struct Cache {
-    var dimensions = [ViewDimensions]()
-  }
-
-  func makeCache(subviews: Subviews) -> Cache {
-    .init()
-  }
-
-  func updateCache(_ cache: inout Cache, subviews: Subviews) {
-    cache.dimensions.removeAll()
-  }
-
-  func sizeThatFits(
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) -> CGSize {
-    let bounds = CGSize(
-      width: min(
-        max(minWidth ?? .zero, proposal.width ?? idealWidth ?? .zero),
-        maxWidth ?? CGFloat.infinity
-      ),
-      height: min(
-        max(minHeight ?? .zero, proposal.height ?? idealHeight ?? .zero),
-        maxHeight ?? CGFloat.infinity
-      )
-    )
-    let proposal = ProposedViewSize(bounds)
-
-    var subviewSizes = CGSize.zero
-    cache.dimensions = subviews.map { subview -> ViewDimensions in
-      let dimensions = subview.dimensions(in: proposal)
-      if dimensions.width > subviewSizes.width {
-        subviewSizes.width = dimensions.width
-      }
-      if dimensions.height > subviewSizes.height {
-        subviewSizes.height = dimensions.height
-      }
-      return dimensions
-    }
-
-    var size = CGSize.zero
-    if let minWidth = minWidth,
-       bounds.width < subviewSizes.width
-    {
-      size.width = max(bounds.width, minWidth)
-    } else if let maxWidth = maxWidth,
-              bounds.width > subviewSizes.width
-    {
-      size.width = min(bounds.width, maxWidth)
-    } else {
-      size.width = subviewSizes.width
-    }
-    if let minHeight = minHeight,
-       bounds.height < subviewSizes.height
-    {
-      size.height = max(bounds.height, minHeight)
-    } else if let maxHeight = maxHeight,
-              bounds.height > subviewSizes.height
-    {
-      size.height = min(bounds.height, maxHeight)
-    } else {
-      size.height = subviewSizes.height
-    }
-
-    return size
-  }
-
-  func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) {
-    let proposal = ProposedViewSize(bounds.size)
-    let frameDimensions = ViewDimensions(
-      size: .init(width: bounds.width, height: bounds.height),
-      alignmentGuides: [:]
-    )
-
-    for (index, subview) in subviews.enumerated() {
-      subview.place(
-        at: .init(
-          x: bounds.minX + frameDimensions[alignment.horizontal]
-            - cache.dimensions[index][alignment.horizontal],
-          y: bounds.minY + frameDimensions[alignment.vertical]
-            - cache.dimensions[index][alignment.vertical]
-        ),
-        proposal: proposal
-      )
-    }
-  }
-}
-
-public extension _FlexFrameLayout {
-  func _visitChildren<V>(_ visitor: V, content: Content) where V: ViewVisitor {
-    visitor.visit(FlexFrameLayout(
-      minWidth: minWidth, idealWidth: idealWidth, maxWidth: maxWidth,
-      minHeight: minHeight, idealHeight: idealHeight, maxHeight: maxHeight,
-      alignment: alignment
-    ).callAsFunction {
-      content
-    })
-  }
-}

Sources/TokamakCore/Fiber/Layout/_FrameLayout+Layout.swift

@@ -1,103 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 5/28/22.
-//
-
-import Foundation
-
-/// A `Layout` container that requests a specific size on one or more axes.
-///
-/// The container proposes the constrained size to its children,
-/// then places them with `alignment` in the constrained bounds.
-///
-/// Children request their own size, so they may overflow this container.
-///
-/// If no fixed size is specified for a an axis, the container will use the size of its children.
-private struct FrameLayout: Layout {
-  let width: CGFloat?
-  let height: CGFloat?
-  let alignment: Alignment
-
-  struct Cache {
-    var dimensions = [ViewDimensions]()
-  }
-
-  func makeCache(subviews: Subviews) -> Cache {
-    .init()
-  }
-
-  func updateCache(_ cache: inout Cache, subviews: Subviews) {
-    cache.dimensions.removeAll()
-  }
-
-  func sizeThatFits(
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) -> CGSize {
-    var size = CGSize.zero
-    let proposal = ProposedViewSize(
-      width: width ?? proposal.width,
-      height: height ?? proposal.height
-    )
-    cache.dimensions = subviews.map { subview -> ViewDimensions in
-      let dimensions = subview.dimensions(in: proposal)
-      if dimensions.width > size.width {
-        size.width = dimensions.width
-      }
-      if dimensions.height > size.height {
-        size.height = dimensions.height
-      }
-      return dimensions
-    }
-    return .init(
-      width: width ?? size.width,
-      height: height ?? size.height
-    )
-  }
-
-  func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout Cache
-  ) {
-    let proposal = ProposedViewSize(bounds.size)
-    let frameDimensions = ViewDimensions(
-      size: .init(width: bounds.width, height: bounds.height),
-      alignmentGuides: [:]
-    )
-
-    for (index, subview) in subviews.enumerated() {
-      subview.place(
-        at: .init(
-          x: bounds.minX + frameDimensions[alignment.horizontal]
-            - cache.dimensions[index][alignment.horizontal],
-          y: bounds.minY + frameDimensions[alignment.vertical]
-            - cache.dimensions[index][alignment.vertical]
-        ),
-        proposal: proposal
-      )
-    }
-  }
-}
-
-public extension _FrameLayout {
-  func _visitChildren<V>(_ visitor: V, content: Content) where V: ViewVisitor {
-    visitor.visit(FrameLayout(width: width, height: height, alignment: alignment).callAsFunction {
-      content
-    })
-  }
-}

Sources/TokamakCore/Fiber/Mutation.swift

@@ -1,38 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/15/22.
-//
-
-import Foundation
-
-public enum Mutation<Renderer: FiberRenderer> {
-  case insert(
-    element: Renderer.ElementType,
-    parent: Renderer.ElementType,
-    index: Int
-  )
-  case remove(element: Renderer.ElementType, parent: Renderer.ElementType?)
-  case replace(
-    parent: Renderer.ElementType,
-    previous: Renderer.ElementType,
-    replacement: Renderer.ElementType
-  )
-  case update(
-    previous: Renderer.ElementType,
-    newContent: Renderer.ElementType.Content,
-    geometry: ViewGeometry
-  )
-  case layout(element: Renderer.ElementType, geometry: ViewGeometry)
-}

Sources/TokamakCore/Fiber/Passes/FiberReconcilerPass.swift

@@ -1,136 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/16/22.
-//
-
-import Foundation
-
-extension FiberReconciler {
-  final class Caches {
-    var elementIndices = [ObjectIdentifier: Int]()
-    var layoutCaches = [ObjectIdentifier: LayoutCache]()
-    var layoutSubviews = [ObjectIdentifier: LayoutSubviews]()
-    var mutations = [Mutation<Renderer>]()
-
-    struct LayoutCache {
-      /// The erased `Layout.Cache` value.
-      var cache: AnyLayout.Cache
-
-      /// Cached values for `sizeThatFits` calls.
-      var sizeThatFits: [SizeThatFitsRequest: CGSize]
-
-      /// Cached values for `dimensions(in:)` calls.
-      var dimensions: [SizeThatFitsRequest: ViewDimensions]
-
-      /// Does this cache need to be updated before using?
-      /// Set to `true` whenever the subviews or the container changes.
-      var isDirty: Bool
-
-      /// Empty the cached values and flag the cache as dirty.
-      mutating func markDirty() {
-        isDirty = true
-        sizeThatFits.removeAll()
-        dimensions.removeAll()
-      }
-
-      struct SizeThatFitsRequest: Hashable {
-        let proposal: ProposedViewSize
-
-        @inlinable
-        init(_ proposal: ProposedViewSize) {
-          self.proposal = proposal
-        }
-
-        func hash(into hasher: inout Hasher) {
-          hasher.combine(proposal.width)
-          hasher.combine(proposal.height)
-        }
-      }
-    }
-
-    func clear() {
-      elementIndices.removeAll()
-      layoutSubviews.removeAll()
-      mutations.removeAll()
-    }
-
-    func layoutCache(for fiber: Fiber) -> LayoutCache? {
-      guard let layout = fiber.layout else { return nil }
-      return layoutCaches[
-        ObjectIdentifier(fiber),
-        default: .init(
-          cache: layout.makeCache(subviews: layoutSubviews(for: fiber)),
-          sizeThatFits: [:],
-          dimensions: [:],
-          isDirty: false
-        )
-      ]
-    }
-
-    func updateLayoutCache<R>(for fiber: Fiber, _ action: (inout LayoutCache) -> R) -> R? {
-      guard let layout = fiber.layout else { return nil }
-      let subviews = layoutSubviews(for: fiber)
-      let key = ObjectIdentifier(fiber)
-      var cache = layoutCaches[
-        key,
-        default: .init(
-          cache: layout.makeCache(subviews: subviews),
-          sizeThatFits: [:],
-          dimensions: [:],
-          isDirty: false
-        )
-      ]
-      // If the cache is dirty, update it before calling `action`.
-      if cache.isDirty {
-        layout.updateCache(&cache.cache, subviews: subviews)
-        cache.isDirty = false
-      }
-      defer { layoutCaches[key] = cache }
-      return action(&cache)
-    }
-
-    func layoutSubviews(for fiber: Fiber) -> LayoutSubviews {
-      layoutSubviews[ObjectIdentifier(fiber), default: .init(fiber)]
-    }
-
-    func elementIndex(for fiber: Fiber, increment: Bool = false) -> Int {
-      let key = ObjectIdentifier(fiber)
-      let result = elementIndices[key, default: 0]
-      if increment {
-        elementIndices[key] = result + 1
-      }
-      return result
-    }
-  }
-}
-
-protocol FiberReconcilerPass {
-  /// Run this pass with the given inputs.
-  ///
-  /// - Parameter reconciler: The `FiberReconciler` running this pass.
-  /// - Parameter root: The node to start the pass from.
-  ///                   The top of the `View` hierarchy when `useDynamicLayout` is enabled.
-  ///                   Otherwise, the same as `reconcileRoot`.
-  /// - Parameter reconcileRoot: A list of topmost nodes that need reconciliation.
-  ///                            When `useDynamicLayout` is enabled, this can be used to limit
-  ///                            the number of operations performed during reconciliation.
-  /// - Parameter caches: The shared cache data for this and other passes.
-  func run<R: FiberRenderer>(
-    in reconciler: FiberReconciler<R>,
-    root: FiberReconciler<R>.TreeReducer.Result,
-    changedFibers: Set<ObjectIdentifier>,
-    caches: FiberReconciler<R>.Caches
-  )
-}

Sources/TokamakCore/Fiber/Passes/LayoutPass.swift

@@ -1,69 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/16/22.
-//
-
-import Foundation
-
-// Layout from the top down.
-struct LayoutPass: FiberReconcilerPass {
-  func run<R>(
-    in reconciler: FiberReconciler<R>,
-    root: FiberReconciler<R>.TreeReducer.Result,
-    changedFibers: Set<ObjectIdentifier>,
-    caches: FiberReconciler<R>.Caches
-  ) where R: FiberRenderer {
-    guard let root = root.fiber else { return }
-    var fiber = root
-
-    while true {
-      // Place subviews for each element fiber as we walk the tree.
-      if fiber.element != nil {
-        caches.updateLayoutCache(for: fiber) { cache in
-          fiber.layout?.placeSubviews(
-            in: .init(
-              origin: .zero,
-              size: fiber.geometry?.dimensions.size ?? reconciler.renderer.sceneSize.value
-            ),
-            proposal: fiber.geometry?.proposal ?? .unspecified,
-            subviews: caches.layoutSubviews(for: fiber),
-            cache: &cache.cache
-          )
-        }
-      }
-
-      if let child = fiber.child {
-        // Continue down the tree.
-        fiber = child
-        continue
-      }
-
-      while fiber.sibling == nil {
-        // Exit at the top of the `View` tree
-        guard let parent = fiber.parent else { return }
-        guard parent !== root else { return }
-        // Walk up to the next parent.
-        fiber = parent
-      }
-
-      // Walk across to the next sibling.
-      fiber = fiber.sibling!
-    }
-  }
-}
-
-extension FiberReconcilerPass where Self == LayoutPass {
-  static var layout: LayoutPass { .init() }
-}

Sources/TokamakCore/Fiber/Passes/ReconcilePass.swift

@@ -1,296 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/16/22.
-//
-
-import Foundation
-
-/// Walk the current tree, recomputing at each step to check for discrepancies.
-///
-/// Parent-first depth-first traversal.
-/// Take this `View` tree for example.
-/// ```swift
-/// VStack {
-///   HStack {
-///     Text("A")
-///     Text("B")
-///   }
-///   Text("C")
-/// }
-/// ```
-/// Basically, we read it like this:
-/// 1. `VStack` has children, so we go to it's first child, `HStack`.
-/// 2. `HStack` has children, so we go further to it's first child, `Text`.
-/// 3. `Text` has no child, but has a sibling, so we go to that.
-/// 4. `Text` has no child and no sibling, so we return to the `HStack`.
-/// 5. We've already read the children, so we look for a sibling, `Text`.
-/// 6. `Text` has no children and no sibling, so we return to the `VStack.`
-/// We finish once we've returned to the root element.
-/// ```
-///    ┌──────┐
-///    │VStack│
-///    └──┬───┘
-///   ▲ 1 │
-///   │   └──►┌──────┐
-///   │       │HStack│
-///   │     ┌─┴───┬──┘
-///   │     │   ▲ │ 2
-///   │     │   │ │  ┌────┐
-///   │     │   │ └─►│Text├─┐
-/// 6 │     │ 4 │    └────┘ │
-///   │     │   │           │ 3
-///   │   5 │   │    ┌────┐ │
-///   │     │   └────┤Text│◄┘
-///   │     │        └────┘
-///   │     │
-///   │     └►┌────┐
-///   │       │Text│
-///   └───────┴────┘
-/// ```
-struct ReconcilePass: FiberReconcilerPass {
-  func run<R>(
-    in reconciler: FiberReconciler<R>,
-    root: FiberReconciler<R>.TreeReducer.Result,
-    changedFibers: Set<ObjectIdentifier>,
-    caches: FiberReconciler<R>.Caches
-  ) where R: FiberRenderer {
-    var node = root
-
-    // Enabled when we reach the `reconcileRoot`.
-    var shouldReconcile = false
-
-    while true {
-      if !shouldReconcile {
-        if let fiber = node.fiber,
-           changedFibers.contains(ObjectIdentifier(fiber))
-        {
-          shouldReconcile = true
-        } else if let alternate = node.fiber?.alternate,
-                  changedFibers.contains(ObjectIdentifier(alternate))
-        {
-          shouldReconcile = true
-        }
-      }
-
-      // If this fiber has an element, set its `elementIndex`
-      // and increment the `elementIndices` value for its `elementParent`.
-      if node.fiber?.element != nil,
-         let elementParent = node.fiber?.elementParent
-      {
-        node.fiber?.elementIndex = caches.elementIndex(for: elementParent, increment: true)
-      }
-
-      // Perform work on the node.
-      if shouldReconcile,
-         let mutation = reconcile(node, in: reconciler, caches: caches)
-      {
-        caches.mutations.append(mutation)
-      }
-
-      // Ensure the `TreeReducer` can access any necessary state.
-      node.elementIndices = caches.elementIndices
-      // Pass view traits down to the nearest element fiber.
-      if let traits = node.fiber?.outputs.traits,
-         !traits.values.isEmpty
-      {
-        node.nextTraits.values.merge(traits.values, uniquingKeysWith: { $1 })
-      }
-
-      // Update `DynamicProperty`s before accessing the `View`'s body.
-      node.fiber?.updateDynamicProperties()
-      // Compute the children of the node.
-      let reducer = FiberReconciler<R>.TreeReducer.SceneVisitor(initialResult: node)
-      node.visitChildren(reducer)
-
-      node.fiber?.preferences?.reset()
-
-      if reconciler.renderer.useDynamicLayout,
-         let fiber = node.fiber
-      {
-        if let element = fiber.element,
-           let elementParent = fiber.elementParent
-        {
-          let parentKey = ObjectIdentifier(elementParent)
-          let subview = LayoutSubview(
-            id: ObjectIdentifier(fiber),
-            traits: fiber.outputs.traits,
-            fiber: fiber,
-            element: element,
-            caches: caches
-          )
-          caches.layoutSubviews[parentKey, default: .init(elementParent)].storage.append(subview)
-        }
-      }
-
-      // Setup the alternate if it doesn't exist yet.
-      if node.fiber?.alternate == nil {
-        _ = node.fiber?.createAndBindAlternate?()
-      }
-
-      // Walk down all the way into the deepest child.
-      if let child = reducer.result.child {
-        node = child
-        continue
-      } else if let alternateChild = node.fiber?.alternate?.child {
-        // The alternate has a child that no longer exists.
-        if let parent = node.fiber?.element != nil ? node.fiber : node.fiber?.elementParent {
-          invalidateCache(for: parent, in: reconciler, caches: caches)
-        }
-        walk(alternateChild) { node in
-          if let element = node.element,
-             let parent = node.elementParent?.element
-          {
-            // Removals must happen in reverse order, so a child element
-            // is removed before its parent.
-            caches.mutations.insert(.remove(element: element, parent: parent), at: 0)
-          }
-          return true
-        }
-      }
-      if reducer.result.child == nil {
-        // Make sure we clear the child if there was none
-        node.fiber?.child = nil
-        node.fiber?.alternate?.child = nil
-      }
-
-      // If we've made it back to the root, then exit.
-      if node === root {
-        return
-      }
-
-      // Now walk back up the tree until we find a sibling.
-      while node.sibling == nil {
-        if let fiber = node.fiber,
-           fiber.element != nil
-        {
-          propagateCacheInvalidation(for: fiber, in: reconciler, caches: caches)
-        }
-
-        if let preferences = node.fiber?.preferences {
-          if let action = node.fiber?.outputs.preferenceAction {
-            action(preferences)
-          }
-          if let parentPreferences = node.fiber?.preferenceParent?.preferences {
-            parentPreferences.merge(preferences)
-          }
-        }
-
-        var alternateSibling = node.fiber?.alternate?.sibling
-        // The alternate had siblings that no longer exist.
-        while alternateSibling != nil {
-          if let fiber = alternateSibling?.elementParent {
-            invalidateCache(for: fiber, in: reconciler, caches: caches)
-          }
-          if let element = alternateSibling?.element,
-             let parent = alternateSibling?.elementParent?.element
-          {
-            // Removals happen in reverse order, so a child element is removed before
-            // its parent.
-            caches.mutations.insert(.remove(element: element, parent: parent), at: 0)
-          }
-          alternateSibling = alternateSibling?.sibling
-        }
-        guard let parent = node.parent else { return }
-        // When we walk back to the root, exit
-        guard parent !== root.fiber?.alternate else { return }
-        node = parent
-      }
-
-      if let fiber = node.fiber {
-        propagateCacheInvalidation(for: fiber, in: reconciler, caches: caches)
-      }
-
-      // Walk across to the sibling, and repeat.
-      node = node.sibling!
-    }
-  }
-
-  /// Compare `node` with its alternate, and add any mutations to the list.
-  func reconcile<R: FiberRenderer>(
-    _ node: FiberReconciler<R>.TreeReducer.Result,
-    in reconciler: FiberReconciler<R>,
-    caches: FiberReconciler<R>.Caches
-  ) -> Mutation<R>? {
-    if let element = node.fiber?.element,
-       let index = node.fiber?.elementIndex,
-       let parent = node.fiber?.elementParent?.element
-    {
-      if node.fiber?.alternate == nil { // This didn't exist before (no alternate)
-        if let fiber = node.fiber {
-          invalidateCache(for: fiber, in: reconciler, caches: caches)
-        }
-        return .insert(element: element, parent: parent, index: index)
-      } else if node.fiber?.typeInfo?.type != node.fiber?.alternate?.typeInfo?.type,
-                let previous = node.fiber?.alternate?.element
-      {
-        if let fiber = node.fiber {
-          invalidateCache(for: fiber, in: reconciler, caches: caches)
-        }
-        // This is a completely different type of view.
-        return .replace(parent: parent, previous: previous, replacement: element)
-      } else if let newContent = node.newContent,
-                newContent != element.content
-      {
-        if let fiber = node.fiber {
-          invalidateCache(for: fiber, in: reconciler, caches: caches)
-        }
-        // This is the same type of view, but its backing data has changed.
-        return .update(
-          previous: element,
-          newContent: newContent,
-          geometry: node.fiber?.geometry ?? .init(
-            origin: .init(origin: .zero),
-            dimensions: .init(size: .zero, alignmentGuides: [:]),
-            proposal: .unspecified
-          )
-        )
-      }
-    }
-    return nil
-  }
-
-  /// Remove cached size values if something changed.
-  func invalidateCache<R: FiberRenderer>(
-    for fiber: FiberReconciler<R>.Fiber,
-    in reconciler: FiberReconciler<R>,
-    caches: FiberReconciler<R>.Caches
-  ) {
-    guard reconciler.renderer.useDynamicLayout else { return }
-    caches.updateLayoutCache(for: fiber) { cache in
-      cache.markDirty()
-    }
-    if let alternate = fiber.alternate {
-      caches.updateLayoutCache(for: alternate) { cache in
-        cache.markDirty()
-      }
-    }
-  }
-
-  @inlinable
-  func propagateCacheInvalidation<R: FiberRenderer>(
-    for fiber: FiberReconciler<R>.Fiber,
-    in reconciler: FiberReconciler<R>,
-    caches: FiberReconciler<R>.Caches
-  ) {
-    guard caches.layoutCache(for: fiber)?.isDirty ?? false,
-          let elementParent = fiber.elementParent
-    else { return }
-    invalidateCache(for: elementParent, in: reconciler, caches: caches)
-  }
-}
-
-extension FiberReconcilerPass where Self == ReconcilePass {
-  static var reconcile: ReconcilePass { ReconcilePass() }
-}

Sources/TokamakCore/Fiber/Scene/SceneArguments.swift

@@ -1,25 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 5/30/22.
-//
-
-import Foundation
-
-public extension Scene {
-  // By default, we simply pass the inputs through without modifications.
-  static func _makeScene(_ inputs: SceneInputs<Self>) -> SceneOutputs {
-    .init(inputs: inputs)
-  }
-}

Sources/TokamakCore/Fiber/Scene/SceneVisitor.swift

@@ -1,68 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 5/30/22.
-//
-
-/// A type that can visit a `Scene`.
-public protocol SceneVisitor: ViewVisitor {
-  func visit<S: Scene>(_ scene: S)
-}
-
-public extension Scene {
-  func _visitChildren<V: SceneVisitor>(_ visitor: V) {
-    visitor.visit(body)
-  }
-}
-
-/// A type that creates a `Result` by visiting multiple `Scene`s.
-protocol SceneReducer: ViewReducer {
-  associatedtype Result
-  static func reduce<S: Scene>(into partialResult: inout Result, nextScene: S)
-  static func reduce<S: Scene>(partialResult: Result, nextScene: S) -> Result
-}
-
-extension SceneReducer {
-  static func reduce<S: Scene>(into partialResult: inout Result, nextScene: S) {
-    partialResult = Self.reduce(partialResult: partialResult, nextScene: nextScene)
-  }
-
-  static func reduce<S: Scene>(partialResult: Result, nextScene: S) -> Result {
-    var result = partialResult
-    Self.reduce(into: &result, nextScene: nextScene)
-    return result
-  }
-}
-
-/// A `SceneVisitor` that uses a `SceneReducer`
-/// to collapse the `Scene` values into a single `Result`.
-final class SceneReducerVisitor<R: SceneReducer>: SceneVisitor {
-  var result: R.Result
-
-  init(initialResult: R.Result) {
-    result = initialResult
-  }
-
-  func visit<S>(_ scene: S) where S: Scene {
-    R.reduce(into: &result, nextScene: scene)
-  }
-
-  func visit<V>(_ view: V) where V: View {
-    R.reduce(into: &result, nextView: view)
-  }
-}
-
-extension SceneReducer {
-  typealias SceneVisitor = SceneReducerVisitor<Self>
-}

Sources/TokamakCore/Fiber/ViewArguments.swift

@@ -1,101 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/7/22.
-//
-
-import Foundation
-
-/// Data passed to `_makeView` to create the `ViewOutputs` used in reconciling/rendering.
-public struct ViewInputs<V> {
-  public let content: V
-
-  /// Mutate the underlying content with the given inputs.
-  ///
-  /// Used to inject values such as environment values, traits, and preferences into the `View` type.
-  public let updateContent: ((inout V) -> ()) -> ()
-
-  @_spi(TokamakCore)
-  public let environment: EnvironmentBox
-
-  public let traits: _ViewTraitStore?
-
-  public let preferenceStore: _PreferenceStore?
-}
-
-/// Data used to reconcile and render a `View` and its children.
-public struct ViewOutputs {
-  /// A container for the current `EnvironmentValues`.
-  /// This is stored as a reference to avoid copying the environment when unnecessary.
-  let environment: EnvironmentBox
-
-  let preferenceStore: _PreferenceStore?
-
-  /// An action to perform after all preferences values have been reduced.
-  ///
-  /// Called when walking back up the tree in the `ReconcilePass`.
-  let preferenceAction: ((_PreferenceStore) -> ())?
-
-  let traits: _ViewTraitStore?
-}
-
-@_spi(TokamakCore)
-public final class EnvironmentBox {
-  public let environment: EnvironmentValues
-
-  public init(_ environment: EnvironmentValues) {
-    self.environment = environment
-  }
-}
-
-public extension ViewOutputs {
-  init<V>(
-    inputs: ViewInputs<V>,
-    environment: EnvironmentValues? = nil,
-    preferenceStore: _PreferenceStore? = nil,
-    preferenceAction: ((_PreferenceStore) -> ())? = nil,
-    traits: _ViewTraitStore? = nil
-  ) {
-    // Only replace the `EnvironmentBox` when we change the environment.
-    // Otherwise the same box can be reused.
-    self.environment = environment.map(EnvironmentBox.init) ?? inputs.environment
-    self.preferenceStore = preferenceStore
-    self.preferenceAction = preferenceAction
-    self.traits = traits ?? inputs.traits
-  }
-}
-
-public extension View {
-  // By default, we simply pass the inputs through without modifications
-  // or layout considerations.
-  static func _makeView(_ inputs: ViewInputs<Self>) -> ViewOutputs {
-    .init(inputs: inputs)
-  }
-}
-
-public extension ModifiedContent where Content: View, Modifier: ViewModifier {
-  static func _makeView(_ inputs: ViewInputs<Self>) -> ViewOutputs {
-    Modifier._makeView(.init(
-      content: inputs.content.modifier,
-      updateContent: { _ in },
-      environment: inputs.environment,
-      traits: inputs.traits,
-      preferenceStore: inputs.preferenceStore
-    ))
-  }
-
-  func _visitChildren<V>(_ visitor: V) where V: ViewVisitor {
-    modifier._visitChildren(visitor, content: .init(modifier: modifier, view: content))
-  }
-}

Sources/TokamakCore/Fiber/ViewGeometry.swift

@@ -1,66 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/17/22.
-//
-
-import Foundation
-
-public struct ViewGeometry: Equatable {
-  @_spi(TokamakCore)
-  public let origin: ViewOrigin
-
-  @_spi(TokamakCore)
-  public let dimensions: ViewDimensions
-
-  let proposal: ProposedViewSize
-}
-
-/// The position of the `View` relative to its parent.
-public struct ViewOrigin: Equatable {
-  @_spi(TokamakCore)
-  public let origin: CGPoint
-
-  @_spi(TokamakCore)
-  public var x: CGFloat { origin.x }
-  @_spi(TokamakCore)
-  public var y: CGFloat { origin.y }
-}
-
-public struct ViewDimensions: Equatable {
-  @_spi(TokamakCore)
-  public let size: CGSize
-
-  @_spi(TokamakCore)
-  public let alignmentGuides: [ObjectIdentifier: CGFloat]
-
-  public var width: CGFloat { size.width }
-  public var height: CGFloat { size.height }
-
-  public subscript(guide: HorizontalAlignment) -> CGFloat {
-    self[explicit: guide] ?? guide.id.defaultValue(in: self)
-  }
-
-  public subscript(guide: VerticalAlignment) -> CGFloat {
-    self[explicit: guide] ?? guide.id.defaultValue(in: self)
-  }
-
-  public subscript(explicit guide: HorizontalAlignment) -> CGFloat? {
-    alignmentGuides[.init(guide.id)]
-  }
-
-  public subscript(explicit guide: VerticalAlignment) -> CGFloat? {
-    alignmentGuides[.init(guide.id)]
-  }
-}

Sources/TokamakCore/Fiber/ViewVisitor.swift

@@ -1,66 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/3/22.
-//
-
-/// A type that can visit a `View`.
-public protocol ViewVisitor {
-  func visit<V: View>(_ view: V)
-}
-
-public extension View {
-  func _visitChildren<V: ViewVisitor>(_ visitor: V) {
-    visitor.visit(body)
-  }
-}
-
-public typealias ViewVisitorF<V: ViewVisitor> = (V) -> ()
-
-/// A type that creates a `Result` by visiting multiple `View`s.
-protocol ViewReducer {
-  associatedtype Result
-  static func reduce<V: View>(into partialResult: inout Result, nextView: V)
-  static func reduce<V: View>(partialResult: Result, nextView: V) -> Result
-}
-
-extension ViewReducer {
-  static func reduce<V: View>(into partialResult: inout Result, nextView: V) {
-    partialResult = Self.reduce(partialResult: partialResult, nextView: nextView)
-  }
-
-  static func reduce<V: View>(partialResult: Result, nextView: V) -> Result {
-    var result = partialResult
-    Self.reduce(into: &result, nextView: nextView)
-    return result
-  }
-}
-
-/// A `ViewVisitor` that uses a `ViewReducer`
-/// to collapse the `View` values into a single `Result`.
-final class ReducerVisitor<R: ViewReducer>: ViewVisitor {
-  var result: R.Result
-
-  init(initialResult: R.Result) {
-    result = initialResult
-  }
-
-  func visit<V>(_ view: V) where V: View {
-    R.reduce(into: &result, nextView: view)
-  }
-}
-
-extension ViewReducer {
-  typealias Visitor = ReducerVisitor<Self>
-}

Sources/TokamakCore/Fiber/walk.swift

@@ -1,86 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 2/11/22.
-//
-
-@_spi(TokamakCore)
-public enum WalkWorkResult<Success> {
-  case `continue`
-  case `break`(with: Success)
-  case pause
-}
-
-@_spi(TokamakCore)
-public enum WalkResult<Renderer: FiberRenderer, Success> {
-  case success(Success)
-  case finished
-  case paused(at: FiberReconciler<Renderer>.Fiber)
-}
-
-/// Walk a fiber tree from `root` until the `work` predicate returns `false`.
-@_spi(TokamakCore)
-@discardableResult
-public func walk<Renderer: FiberRenderer>(
-  _ root: FiberReconciler<Renderer>.Fiber,
-  _ work: @escaping (FiberReconciler<Renderer>.Fiber) throws -> Bool
-) rethrows -> WalkResult<Renderer, ()> {
-  try walk(root) {
-    try work($0) ? .continue : .pause
-  }
-}
-
-/// Parent-first depth-first traversal of a `Fiber` tree.
-/// `work` is called with each `Fiber` in the tree as they are entered.
-///
-/// Traversal uses the following process:
-/// 1. Perform work on the current `Fiber`.
-/// 2. If the `Fiber` has a child, repeat from (1) with the child.
-/// 3. If the `Fiber` does not have a sibling, walk up until we find a `Fiber` that does have one.
-/// 4. Walk across to the sibling.
-///
-/// When the `root` is reached, the loop exits.
-@_spi(TokamakCore)
-public func walk<Renderer: FiberRenderer, Success>(
-  _ root: FiberReconciler<Renderer>.Fiber,
-  _ work: @escaping (FiberReconciler<Renderer>.Fiber) throws -> WalkWorkResult<Success>
-) rethrows -> WalkResult<Renderer, Success> {
-  var current = root
-  while true {
-    // Perform work on the node
-    switch try work(current) {
-    case .continue: break
-    case let .break(success): return .success(success)
-    case .pause: return .paused(at: current)
-    }
-    // Walk into the child
-    if let child = current.child {
-      current = child
-      continue
-    }
-    // When we walk back to the root, exit
-    if current === root {
-      return .finished
-    }
-    // Walk back up until we find a sibling
-    while current.sibling == nil {
-      // When we walk back to the root, exit
-      guard let parent = current.parent,
-            parent !== root else { return .finished }
-      current = parent
-    }
-    // Walk the sibling
-    current = current.sibling!
-  }
-}

Sources/TokamakCore/Modifiers/AspectRatioLayout.swift

@@ -14,8 +14,7 @@
 
 import Foundation
 
-@frozen
+@frozen public enum ContentMode: Hashable, CaseIterable {
-public enum ContentMode: Hashable, CaseIterable {
   case fit
   case fill
 }

Sources/TokamakCore/Modifiers/Effects/OffsetEffect.swift

@@ -17,8 +17,7 @@
 
 import Foundation
 
-@frozen
+@frozen public struct _OffsetEffect: GeometryEffect, Equatable {
-public struct _OffsetEffect: GeometryEffect, Equatable {
   public var offset: CGSize
 
   @inlinable

Sources/TokamakCore/Modifiers/Effects/ScaleEffect.swift

@@ -17,8 +17,7 @@
 
 import Foundation
 
-@frozen
+@frozen public struct _ScaleEffect: GeometryEffect, Equatable {
-public struct _ScaleEffect: GeometryEffect, Equatable {
   public var scale: CGSize
   public var anchor: UnitPoint
 

Sources/TokamakCore/Modifiers/ModifiedContent.swift

@@ -13,16 +13,14 @@
 // limitations under the License.
 
 protocol ModifierContainer {
-  var environmentModifier: _EnvironmentModifier? { get }
+  var environmentModifier: EnvironmentModifier? { get }
 }
 
 protocol ModifiedContentProtocol {}
 
 /// A value with a modifier applied to it.
 public struct ModifiedContent<Content, Modifier>: ModifiedContentProtocol {
-  @Environment(\.self)
+  @Environment(\.self) public var environment
-  public var environment
-
   public typealias Body = Never
   public private(set) var content: Content
   public private(set) var modifier: Modifier
@@ -34,7 +32,7 @@ public struct ModifiedContent<Content, Modifier>: ModifiedContentProtocol {
 }
 
 extension ModifiedContent: ModifierContainer {
-  var environmentModifier: _EnvironmentModifier? { modifier as? _EnvironmentModifier }
+  var environmentModifier: EnvironmentModifier? { modifier as? EnvironmentModifier }
 }
 
 extension ModifiedContent: EnvironmentReader where Modifier: EnvironmentReader {

Sources/TokamakCore/Modifiers/StyleModifiers.swift

@@ -24,18 +24,6 @@ public struct _BackgroundLayout<Content, Background>: _PrimitiveView
   public let content: Content
   public let background: Background
   public let alignment: Alignment
-
-  @_spi(TokamakCore)
-  public init(content: Content, background: Background, alignment: Alignment) {
-    self.content = content
-    self.background = background
-    self.alignment = alignment
-  }
-
-  public func _visitChildren<V>(_ visitor: V) where V: ViewVisitor {
-    visitor.visit(background)
-    visitor.visit(content)
-  }
 }
 
 public struct _BackgroundModifier<Background>: ViewModifier, EnvironmentReader
@@ -89,8 +77,7 @@ public extension View {
   }
 }
 
-@frozen
+@frozen public struct _BackgroundShapeModifier<Style, Bounds>: ViewModifier, EnvironmentReader
-public struct _BackgroundShapeModifier<Style, Bounds>: ViewModifier, EnvironmentReader
   where Style: ShapeStyle, Bounds: Shape
 {
   public var environment: EnvironmentValues!
@@ -142,11 +129,6 @@ public struct _OverlayLayout<Content, Overlay>: _PrimitiveView
   public let content: Content
   public let overlay: Overlay
   public let alignment: Alignment
-
-  public func _visitChildren<V>(_ visitor: V) where V: ViewVisitor {
-    visitor.visit(content)
-    visitor.visit(overlay)
-  }
 }
 
 public struct _OverlayModifier<Overlay>: ViewModifier, EnvironmentReader

Sources/TokamakCore/Modifiers/ViewModifier.swift

@@ -16,23 +16,6 @@ public protocol ViewModifier {
   typealias Content = _ViewModifier_Content<Self>
   associatedtype Body: View
   func body(content: Content) -> Self.Body
-
-  static func _makeView(_ inputs: ViewInputs<Self>) -> ViewOutputs
-  func _visitChildren<V>(_ visitor: V, content: Content) where V: ViewVisitor
-}
-
-public extension ViewModifier {
-  static func _makeView(_ inputs: ViewInputs<Self>) -> ViewOutputs {
-    .init(inputs: inputs)
-  }
-
-  func _visitChildren<V>(_ visitor: V, content: Content) where V: ViewVisitor {
-    if Body.self == Never.self {
-      content.visitChildren(visitor)
-    } else {
-      visitor.visit(body(content: content))
-    }
-  }
 }
 
 public struct _ViewModifier_Content<Modifier>: View
@@ -40,27 +23,15 @@ public struct _ViewModifier_Content<Modifier>: View
 {
   public let modifier: Modifier
   public let view: AnyView
-  let visitChildren: (ViewVisitor) -> ()
 
   public init(modifier: Modifier, view: AnyView) {
     self.modifier = modifier
     self.view = view
-    visitChildren = { $0.visit(view) }
-  }
-
-  public init<V: View>(modifier: Modifier, view: V) {
-    self.modifier = modifier
-    self.view = AnyView(view)
-    visitChildren = { $0.visit(view) }
   }
 
   public var body: some View {
     view
   }
-
-  public func _visitChildren<V>(_ visitor: V) where V: ViewVisitor {
-    visitChildren(visitor)
-  }
 }
 
 public extension View {

Sources/TokamakCore/MountedViews/MountedCompositeView.swift

@@ -78,6 +78,9 @@ final class MountedCompositeView<R: Renderer>: MountedCompositeElement<R> {
 
       if let preferenceModifier = self.view.view as? _PreferenceWritingViewProtocol {
         self.view = preferenceModifier.modifyPreferenceStore(&self.preferenceStore)
+        if let parent = parent {
+          parent.preferenceStore.merge(with: self.preferenceStore)
+        }
       }
 
       if let preferenceReader = self.view.view as? _PreferenceReadingViewProtocol {

Sources/TokamakCore/MountedViews/MountedElement.swift

@@ -94,9 +94,13 @@ public class MountedElement<R: Renderer> {
 
   public internal(set) var environmentValues: EnvironmentValues
 
-  private(set) weak var parent: MountedElement<R>?
+  weak var parent: MountedElement<R>?
-
+  /// `didSet` on this field propagates the preference changes up the view tree.
-  var preferenceStore: _PreferenceStore = .init()
+  var preferenceStore: _PreferenceStore = .init() {
+    didSet {
+      parent?.preferenceStore.merge(with: preferenceStore)
+    }
+  }
 
   public internal(set) var viewTraits: _ViewTraitStore
 
@@ -106,7 +110,6 @@ public class MountedElement<R: Renderer> {
     self.environmentValues = environmentValues
     viewTraits = .init()
     updateEnvironment()
-    connectParentPreferenceStore()
   }
 
   init(_ scene: _AnyScene, _ environmentValues: EnvironmentValues, _ parent: MountedElement<R>?) {
@@ -115,7 +118,6 @@ public class MountedElement<R: Renderer> {
     self.environmentValues = environmentValues
     viewTraits = .init()
     updateEnvironment()
-    connectParentPreferenceStore()
   }
 
   init(
@@ -129,7 +131,6 @@ public class MountedElement<R: Renderer> {
     self.environmentValues = environmentValues
     self.viewTraits = viewTraits
     updateEnvironment()
-    connectParentPreferenceStore()
   }
 
   func updateEnvironment() {
@@ -144,10 +145,6 @@ public class MountedElement<R: Renderer> {
     }
   }
 
-  func connectParentPreferenceStore() {
-    preferenceStore.parent = parent?.preferenceStore
-  }
-
   /// You must call `super.prepareForMount` before all other mounting work.
   func prepareForMount(with transaction: Transaction) {
     // `GroupView`'s don't really mount, so let their children transition if the group can.

Sources/TokamakCore/Preferences/PreferenceKey.swift

@@ -25,41 +25,12 @@ public extension PreferenceKey where Self.Value: ExpressibleByNilLiteral {
   static var defaultValue: Value { nil }
 }
 
-final class _PreferenceValueStorage: CustomDebugStringConvertible {
-  /// Every value the `Key` has had.
-  var valueList: [Any]
-
-  var debugDescription: String {
-    valueList.debugDescription
-  }
-
-  init<Key: PreferenceKey>(_ key: Key.Type = Key.self) {
-    valueList = []
-  }
-
-  init(valueList: [Any]) {
-    self.valueList = valueList
-  }
-
-  func merge(_ other: _PreferenceValueStorage) {
-    valueList.append(contentsOf: other.valueList)
-  }
-
-  func reset() {
-    valueList = []
-  }
-}
-
 public struct _PreferenceValue<Key> where Key: PreferenceKey {
-  var storage: _PreferenceValueStorage
+  /// Every value the `Key` has had.
-
+  var valueList: [Key.Value]
-  init(storage: _PreferenceValueStorage) {
-    self.storage = storage
-  }
-
   /// The latest value.
   public var value: Key.Value {
-    reduce(storage.valueList.compactMap { $0 as? Key.Value })
+    reduce(valueList)
   }
 
   func reduce(_ values: [Key.Value]) -> Key.Value {
@@ -77,79 +48,38 @@ public extension _PreferenceValue {
   }
 }
 
-public final class _PreferenceStore: CustomDebugStringConvertible {
+public struct _PreferenceStore {
-  /// The values of the `_PreferenceStore` on the last update.
-  private var previousValues: [ObjectIdentifier: _PreferenceValueStorage]
   /// The backing values of the `_PreferenceStore`.
-  private var values: [ObjectIdentifier: _PreferenceValueStorage]
+  private var values: [String: Any]
 
-  weak var parent: _PreferenceStore?
+  public init(values: [String: Any] = [:]) {
-
-  public var debugDescription: String {
-    "Preferences (\(ObjectIdentifier(self))): \(values)"
-  }
-
-  init(values: [ObjectIdentifier: _PreferenceValueStorage] = [:]) {
-    previousValues = [:]
     self.values = values
   }
 
-  /// Retrieve a late-binding token for `key`, or save the default value if it does not yet exist.
   public func value<Key>(forKey key: Key.Type = Key.self) -> _PreferenceValue<Key>
     where Key: PreferenceKey
   {
-    let keyID = ObjectIdentifier(key)
+    values[String(reflecting: key)] as? _PreferenceValue<Key>
-    let storage: _PreferenceValueStorage
+      ?? _PreferenceValue(valueList: [Key.defaultValue])
-    if let existing = values[keyID] {
-      storage = existing
-    } else {
-      storage = .init(key)
-      values[keyID] = storage
-    }
-    return _PreferenceValue(storage: storage)
   }
 
-  /// Retrieve the value `Key` had on the last update.
+  public mutating func insert<Key>(_ value: Key.Value, forKey key: Key.Type = Key.self)
-  ///
-  /// Used to check if the value changed during the last update.
-  func previousValue<Key>(forKey key: Key.Type = Key.self) -> _PreferenceValue<Key>
     where Key: PreferenceKey
   {
-    _PreferenceValue(storage: previousValues[ObjectIdentifier(key)] ?? .init(key))
+    let previousValues = self.value(forKey: key).valueList
+    values[String(reflecting: key)] = _PreferenceValue<Key>(valueList: previousValues + [value])
   }
 
-  public func insert<Key>(_ value: Key.Value, forKey key: Key.Type = Key.self)
+  public mutating func merge(with other: Self) {
-    where Key: PreferenceKey
+    self = merging(with: other)
-  {
-    let keyID = ObjectIdentifier(key)
-    if !values.keys.contains(keyID) {
-      values[keyID] = .init(key)
-    }
-    values[keyID]?.valueList.append(value)
-    parent?.insert(value, forKey: key)
   }
 
-  func merge(_ other: _PreferenceStore) {
+  public func merging(with other: Self) -> Self {
-    for (key, otherStorage) in other.values {
+    var result = values
-      if let storage = values[key] {
+    for (key, value) in other.values {
-        storage.merge(otherStorage)
+      result[key] = value
-      } else {
-        values[key] = .init(valueList: otherStorage.valueList)
-      }
-    }
-  }
-
-  /// Copies `values` to `previousValues`, and clears `values`.
-  ///
-  /// Each reconcile pass the preferences are collected from scratch, so we need to
-  /// clear out the old values.
-  func reset() {
-    previousValues = values.mapValues {
-      _PreferenceValueStorage(valueList: $0.valueList)
-    }
-    for storage in values.values {
-      storage.reset()
     }
+    return .init(values: result)
   }
 }
 

Sources/TokamakCore/Preferences/_PreferenceActionModifier.swift

@@ -25,26 +25,12 @@ public struct _PreferenceActionModifier<Key>: _PreferenceWritingModifierProtocol
 
   public func body(_ content: Content, with preferenceStore: inout _PreferenceStore) -> AnyView {
     let value = preferenceStore.value(forKey: Key.self)
-    let previousValue = value.reduce((value.storage.valueList as? [Key.Value] ?? []).dropLast())
+    let previousValue = value.reduce(value.valueList.dropLast())
     if previousValue != value.value {
       action(value.value)
     }
     return content.view
   }
-
-  public static func _makeView(_ inputs: ViewInputs<Self>) -> ViewOutputs {
-    .init(
-      inputs: inputs,
-      preferenceStore: inputs.preferenceStore ?? .init(),
-      preferenceAction: {
-        let value = $0.value(forKey: Key.self).value
-        let previousValue = $0.previousValue(forKey: Key.self).value
-        if value != previousValue {
-          inputs.content.action(value)
-        }
-      }
-    )
-  }
 }
 
 public extension View {

Sources/TokamakCore/Preferences/_PreferenceReadingView.swift

@@ -20,12 +20,11 @@
 public struct _DelayedPreferenceView<Key, Content>: View, _PreferenceReadingViewProtocol
   where Key: PreferenceKey, Content: View
 {
-  @State
+  @State private var resolvedValue: _PreferenceValue<Key> = _PreferenceValue(
-  private var resolvedValue: _PreferenceValue<Key> = _PreferenceValue(storage: .init(Key.self))
+    valueList: [Key.defaultValue]
+  )
   public let transform: (_PreferenceValue<Key>) -> Content
 
-  private var valueReference: _PreferenceValue<Key>?
-
   public init(transform: @escaping (_PreferenceValue<Key>) -> Content) {
     self.transform = transform
   }
@@ -35,18 +34,7 @@ public struct _DelayedPreferenceView<Key, Content>: View, _PreferenceReadingView
   }
 
   public var body: some View {
-    transform(valueReference ?? resolvedValue)
+    transform(resolvedValue)
-  }
-
-  public static func _makeView(_ inputs: ViewInputs<Self>) -> ViewOutputs {
-    let preferenceStore = inputs.preferenceStore ?? .init()
-    inputs.updateContent {
-      $0.valueReference = preferenceStore.value(forKey: Key.self)
-    }
-    return .init(
-      inputs: inputs,
-      preferenceStore: preferenceStore
-    )
   }
 }
 
@@ -81,7 +69,7 @@ public extension View {
   ) -> some View
     where Key: PreferenceKey, T: View
   {
-    Key._delay { self.overlay($0._force(transform)) }
+    Key._delay { self.overlay(transform($0.value)) }
   }
 
   func backgroundPreferenceValue<Key, T>(
@@ -90,6 +78,6 @@ public extension View {
   ) -> some View
     where Key: PreferenceKey, T: View
   {
-    Key._delay { self.background($0._force(transform)) }
+    Key._delay { self.background(transform($0.value)) }
   }
 }

Sources/TokamakCore/Preferences/_PreferenceTransformModifier.swift

@@ -34,18 +34,6 @@ public struct _PreferenceTransformModifier<Key>: _PreferenceWritingModifierProto
     preferenceStore.insert(newValue, forKey: Key.self)
     return content.view
   }
-
-  public static func _makeView(_ inputs: ViewInputs<Self>) -> ViewOutputs {
-    .init(
-      inputs: inputs,
-      preferenceStore: inputs.preferenceStore ?? .init(),
-      preferenceAction: {
-        var value = $0.value(forKey: Key.self).value
-        inputs.content.transform(&value)
-        $0.insert(value, forKey: Key.self)
-      }
-    )
-  }
 }
 
 public extension View {

Sources/TokamakCore/Preferences/_PreferenceWritingModifier.swift

@@ -27,14 +27,6 @@ public struct _PreferenceWritingModifier<Key>: _PreferenceWritingModifierProtoco
     preferenceStore.insert(value, forKey: Key.self)
     return content.view
   }
-
-  public static func _makeView(_ inputs: ViewInputs<Self>) -> ViewOutputs {
-    .init(
-      inputs: inputs,
-      preferenceStore: inputs.preferenceStore ?? .init(),
-      preferenceAction: { $0.insert(inputs.content.value, forKey: Key.self) }
-    )
-  }
 }
 
 extension _PreferenceWritingModifier: Equatable where Key.Value: Equatable {

Sources/TokamakCore/PreviewProvider.swift

@@ -18,8 +18,7 @@ import Foundation
 public protocol PreviewProvider {
   associatedtype Previews: View
 
-  @ViewBuilder
+  @ViewBuilder static var previews: Previews { get }
-  static var previews: Previews { get }
 }
 
 public struct PreviewDevice: RawRepresentable, ExpressibleByStringLiteral {

Sources/TokamakCore/Reflection/Layouts/StructTypeDescriptor.swift

@@ -20,8 +20,7 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-typealias FieldTypeAccessor = @convention(c)
+typealias FieldTypeAccessor = @convention(c) (UnsafePointer<Int>) -> UnsafePointer<Int>
-  (UnsafePointer<Int>) -> UnsafePointer<Int>
 
 struct StructTypeDescriptor {
   let flags: Int32

Sources/TokamakCore/Reflection/Models/PropertyInfo.swift

@@ -20,21 +20,7 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-public struct PropertyInfo: Hashable {
+public struct PropertyInfo {
-  // Hashable/Equatable conformance is not synthesize for metatypes.
-  public static func == (lhs: PropertyInfo, rhs: PropertyInfo) -> Bool {
-    lhs.name == rhs.name && lhs.type == rhs.type && lhs.isVar == rhs.isVar && lhs.offset == rhs
-      .offset && lhs.ownerType == rhs.ownerType
-  }
-
-  public func hash(into hasher: inout Hasher) {
-    hasher.combine(name)
-    hasher.combine(ObjectIdentifier(type))
-    hasher.combine(isVar)
-    hasher.combine(offset)
-    hasher.combine(ObjectIdentifier(ownerType))
-  }
-
   public let name: String
   public let type: Any.Type
   public let isVar: Bool

Sources/TokamakCore/Reflection/Pointers/MetadataOffset.swift

@@ -24,9 +24,7 @@ struct MetadataOffset<Pointee> {
   let offset: Int32
 
   func apply(to ptr: UnsafeRawPointer) -> UnsafePointer<Pointee> {
-    // Data pointers in constant metadata are absolute until SwiftWasm 5.6
+    #if arch(wasm32)
-    // Since SwiftWasm 5.7, they are relative as well as other platforms.
-    #if arch(wasm32) && !compiler(>=5.7)
     return UnsafePointer<Pointee>(bitPattern: Int(offset))!
     #else
     return ptr.advanced(by: numericCast(offset)).assumingMemoryBound(to: Pointee.self)

Sources/TokamakCore/Shapes/AnyShape.swift

@@ -1,76 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-import Foundation
-
-protocol AnyShapeBox {
-  var animatableDataBox: _AnyAnimatableData { get set }
-
-  func path(in rect: CGRect) -> Path
-
-  func sizeThatFits(_ proposal: ProposedViewSize) -> CGSize
-}
-
-private struct ConcreteAnyShapeBox<Base: Shape>: AnyShapeBox {
-  var base: Base
-
-  var animatableDataBox: _AnyAnimatableData {
-    get {
-      _AnyAnimatableData(base.animatableData)
-    }
-    set {
-      guard let newData = newValue.value as? Base.AnimatableData else {
-        // TODO: Should this crash?
-        return
-      }
-
-      base.animatableData = newData
-    }
-  }
-
-  func path(in rect: CGRect) -> Path {
-    base.path(in: rect)
-  }
-
-  func sizeThatFits(_ proposal: ProposedViewSize) -> CGSize {
-    base.sizeThatFits(proposal)
-  }
-}
-
-public struct AnyShape: Shape {
-  var box: AnyShapeBox
-
-  private init(_ box: AnyShapeBox) {
-    self.box = box
-  }
-}
-
-public extension AnyShape {
-  init<S: Shape>(_ shape: S) {
-    box = ConcreteAnyShapeBox(base: shape)
-  }
-
-  func path(in rect: CGRect) -> Path {
-    box.path(in: rect)
-  }
-
-  func sizeThatFits(_ proposal: ProposedViewSize) -> CGSize {
-    box.sizeThatFits(proposal)
-  }
-
-  var animatableData: _AnyAnimatableData {
-    get { box.animatableDataBox }
-    set { box.animatableDataBox = newValue }
-  }
-}

Sources/TokamakCore/Shapes/ContainerRelativeShape.swift

@@ -38,8 +38,7 @@ extension ContainerRelativeShape: InsettableShape {
   }
 
   @usableFromInline
-  @frozen
+  @frozen internal struct _Inset: InsettableShape, DynamicProperty {
-  internal struct _Inset: InsettableShape, DynamicProperty {
     @usableFromInline
     internal var amount: CGFloat
     @inlinable
@@ -77,8 +76,7 @@ private extension EnvironmentValues {
   }
 }
 
-@frozen
+@frozen public struct _ContainerShapeModifier<Shape>: ViewModifier where Shape: InsettableShape {
-public struct _ContainerShapeModifier<Shape>: ViewModifier where Shape: InsettableShape {
   public var shape: Shape
   @inlinable
   public init(shape: Shape) { self.shape = shape }

Sources/TokamakCore/Shapes/ModifiedShapes.swift

@@ -18,9 +18,7 @@
 import Foundation
 
 public struct _StrokedShape<S>: Shape, DynamicProperty where S: Shape {
-  @Environment(\.self)
+  @Environment(\.self) public var environment
-  public var environment
-
   public var shape: S
   public var style: StrokeStyle
 

Sources/TokamakCore/Shapes/Rectangle.swift

@@ -89,11 +89,8 @@ extension RoundedRectangle: InsettableShape {
 
   @usableFromInline
   struct _Inset: InsettableShape {
-    @usableFromInline
+    @usableFromInline var base: RoundedRectangle
-    var base: RoundedRectangle
+    @usableFromInline var amount: CGFloat
-
-    @usableFromInline
-    var amount: CGFloat
 
     @inlinable
     init(base: RoundedRectangle, amount: CGFloat) {

Sources/TokamakCore/Shapes/Shape.swift

@@ -21,18 +21,6 @@ public protocol Shape: Animatable, View {
   func path(in rect: CGRect) -> Path
 
   static var role: ShapeRole { get }
-
-  func sizeThatFits(_ proposal: ProposedViewSize) -> CGSize
-}
-
-public extension Shape {
-  func sizeThatFits(_ proposal: ProposedViewSize) -> CGSize {
-    // TODO: Check if SwiftUI changes this behavior.
-
-    // SwiftUI seems to not compute the path at all and just return
-    // the following.
-    proposal.replacingUnspecifiedDimensions()
-  }
 }
 
 public enum ShapeRole: Hashable {
@@ -66,15 +54,9 @@ public struct FillStyle: Equatable {
   }
 }
 
-public struct _ShapeView<Content, Style>: _PrimitiveView, Layout where Content: Shape,
+public struct _ShapeView<Content, Style>: _PrimitiveView where Content: Shape, Style: ShapeStyle {
-  Style: ShapeStyle
+  @Environment(\.self) public var environment
-{
+  @Environment(\.foregroundColor) public var foregroundColor
-  @Environment(\.self)
-  public var environment
-
-  @Environment(\.foregroundColor)
-  public var foregroundColor
-
   public var shape: Content
   public var style: Style
   public var fillStyle: FillStyle
@@ -84,32 +66,6 @@ public struct _ShapeView<Content, Style>: _PrimitiveView, Layout where Content:
     self.style = style
     self.fillStyle = fillStyle
   }
-
-  public func spacing(subviews: Subviews, cache: inout ()) -> ViewSpacing {
-    .init()
-  }
-
-  public func sizeThatFits(
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout ()
-  ) -> CGSize {
-    proposal.replacingUnspecifiedDimensions()
-  }
-
-  public func placeSubviews(
-    in bounds: CGRect,
-    proposal: ProposedViewSize,
-    subviews: Subviews,
-    cache: inout ()
-  ) {
-    for subview in subviews {
-      subview.place(
-        at: bounds.origin,
-        proposal: .init(width: bounds.width, height: bounds.height)
-      )
-    }
-  }
 }
 
 public extension Shape {

Sources/TokamakCore/Shapes/ShapeStyles/BackgroundStyle.swift

@@ -56,8 +56,7 @@ public extension View {
   }
 }
 
-@frozen
+@frozen public struct _BackgroundStyleModifier<Style>: ViewModifier, EnvironmentModifier,
-public struct _BackgroundStyleModifier<Style>: ViewModifier, _EnvironmentModifier,
   EnvironmentReader
   where Style: ShapeStyle
 {

Sources/TokamakCore/Shapes/ShapeStyles/ForegroundStyle.swift

@@ -71,10 +71,9 @@ public extension View {
   }
 }
 
-@frozen
+@frozen public struct _ForegroundStyleModifier<
-public struct _ForegroundStyleModifier<
   Primary, Secondary, Tertiary
->: ViewModifier, _EnvironmentModifier
+>: ViewModifier, EnvironmentModifier
   where Primary: ShapeStyle, Secondary: ShapeStyle, Tertiary: ShapeStyle
 {
   public var primary: Primary

Sources/TokamakCore/Shapes/ShapeStyles/Gradients/AngularGradient.swift

@@ -17,8 +17,7 @@
 
 import Foundation
 
-@frozen
+@frozen public struct AngularGradient: ShapeStyle, View {
-public struct AngularGradient: ShapeStyle, View {
   internal var gradient: Gradient
   internal var center: UnitPoint
   internal var startAngle: Angle

Sources/TokamakCore/Shapes/ShapeStyles/Gradients/EllipticalGradient.swift

@@ -17,8 +17,7 @@
 
 import Foundation
 
-@frozen
+@frozen public struct EllipticalGradient: ShapeStyle, View {
-public struct EllipticalGradient: ShapeStyle, View {
   internal var gradient: Gradient
   internal var center: UnitPoint
   internal var startRadiusFraction: CGFloat

Sources/TokamakCore/Shapes/ShapeStyles/Gradients/Gradient.swift

@@ -17,10 +17,8 @@
 
 import Foundation
 
-@frozen
+@frozen public struct Gradient: Equatable {
-public struct Gradient: Equatable {
+  @frozen public struct Stop: Equatable {
-  @frozen
-  public struct Stop: Equatable {
     public var color: Color
     public var location: CGFloat
 

Sources/TokamakCore/Shapes/ShapeStyles/Gradients/LinearGradient.swift

@@ -17,8 +17,7 @@
 
 import Foundation
 
-@frozen
+@frozen public struct LinearGradient: ShapeStyle, View {
-public struct LinearGradient: ShapeStyle, View {
   internal var gradient: Gradient
   internal var startPoint: UnitPoint
   internal var endPoint: UnitPoint

Sources/TokamakCore/Shapes/ShapeStyles/Gradients/RadialGradient.swift

@@ -17,8 +17,7 @@
 
 import Foundation
 
-@frozen
+@frozen public struct RadialGradient: ShapeStyle, View {
-public struct RadialGradient: ShapeStyle, View {
   internal var gradient: Gradient
   internal var center: UnitPoint
   internal var startRadius: CGFloat

Sources/TokamakCore/Shapes/ShapeStyles/HierarchicalShapeStyle.swift

@@ -16,8 +16,7 @@
 //
 
 /// A `ShapeStyle` that provides the `primary`, `secondary`, `tertiary`, and `quaternary` styles.
-@frozen
+@frozen public struct HierarchicalShapeStyle: ShapeStyle {
-public struct HierarchicalShapeStyle: ShapeStyle {
   @usableFromInline
   internal var id: UInt32
 

Sources/TokamakCore/Shapes/StrokeStyle.swift

@@ -17,10 +17,6 @@
 
 import Foundation
 
-#if canImport(CoreGraphics)
-import CoreGraphics
-#endif
-
 public struct StrokeStyle: Equatable {
   public var lineWidth: CGFloat
   public var lineCap: CGLineCap

Sources/TokamakCore/StackReconciler.swift

@@ -58,12 +58,6 @@ public final class StackReconciler<R: Renderer> {
    */
   public let rootTarget: R.TargetType
 
-  /** A root renderer's main preference store.
-   */
-  public var preferenceStore: _PreferenceStore {
-    rootElement.preferenceStore
-  }
-
   /** A root of the mounted elements tree to which all other mounted elements are attached to.
    */
   private let rootElement: MountedElement<R>

Sources/TokamakCore/State/State.swift

@@ -23,8 +23,7 @@ protocol WritableValueStorage: ValueStorage {
   var setter: ((Any, Transaction) -> ())? { get set }
 }
 
-@propertyWrapper
+@propertyWrapper public struct State<Value>: DynamicProperty {
-public struct State<Value>: DynamicProperty {
   private let initialValue: Value
 
   var anyInitialValue: Any { initialValue }

Sources/TokamakCore/Stubs/CGStubs.swift

@@ -103,7 +103,7 @@ public struct CGAffineTransform: Equatable {
   /// Returns an affine transformation matrix constructed from a rotation value you provide.
   /// - Parameters:
   ///   - angle: The angle, in radians, by which this matrix rotates the coordinate system axes.
-  ///            A positive value specifies clockwise rotation and a negative value specifies
+  ///            A positive value specifies clockwise rotation and anegative value specifies
   ///            counterclockwise rotation.
   public init(rotationAngle angle: CGFloat) {
     self.init(a: cos(angle), b: sin(angle), c: -sin(angle), d: cos(angle), tx: 0, ty: 0)

Sources/TokamakCore/Styles/ToggleStyle.swift

@@ -25,8 +25,7 @@
 
 public struct ToggleStyleConfiguration {
   public let label: AnyView
-  @Binding
+  @Binding public var isOn: Swift.Bool
-  public var isOn: Swift.Bool
 }
 
 public protocol ToggleStyle {

Sources/TokamakCore/Tokens/LayoutDirection.swift

@@ -1,32 +0,0 @@
-// Copyright 2022 Tokamak contributors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-//
-//  Created by Carson Katri on 6/20/22.
-//
-
-public enum LayoutDirection: Hashable, CaseIterable {
-  case leftToRight
-  case rightToLeft
-}
-
-extension EnvironmentValues {
-  private enum LayoutDirectionKey: EnvironmentKey {
-    static var defaultValue: LayoutDirection = .leftToRight
-  }
-
-  public var layoutDirection: LayoutDirection {
-    get { self[LayoutDirectionKey.self] }
-    set { self[LayoutDirectionKey.self] = newValue }
-  }
-}

Sources/TokamakCore/ViewTraits/TagValueTraitKey.swift

@@ -37,13 +37,11 @@ struct TagValueTraitKey<V>: _ViewTraitKey where V: Hashable {
     case tagged(V)
   }
 
-  @inlinable
+  @inlinable static var defaultValue: Value { .untagged }
-  static var defaultValue: Value { .untagged }
 }
 
 @usableFromInline
 struct IsAuxiliaryContentTraitKey: _ViewTraitKey {
-  @inlinable
+  @inlinable static var defaultValue: Bool { false }
-  static var defaultValue: Bool { false }
   @usableFromInline typealias Value = Bool
 }

Sources/TokamakCore/ViewTraits/Transition/Transition.swift

@@ -17,8 +17,7 @@
 
 import Foundation
 
-@frozen
+@frozen public struct AnyTransition {
-public struct AnyTransition {
   fileprivate let box: _AnyTransitionBox
 
   private init(_ box: _AnyTransitionBox) {
@@ -28,16 +27,14 @@ public struct AnyTransition {
 
 @usableFromInline
 struct TransitionTraitKey: _ViewTraitKey {
-  @inlinable
+  @inlinable static var defaultValue: AnyTransition { .opacity }
-  static var defaultValue: AnyTransition { .opacity }
 
   @usableFromInline typealias Value = AnyTransition
 }
 
 @usableFromInline
 struct CanTransitionTraitKey: _ViewTraitKey {
-  @inlinable
+  @inlinable static var defaultValue: Bool { false }
-  static var defaultValue: Bool { false }
 
   @usableFromInline typealias Value = Bool
 }

Sources/TokamakCore/ViewTraits/_ViewTraitKey.swift

@@ -24,8 +24,7 @@ public protocol _TraitWritingModifierProtocol {
   func modifyViewTraitStore(_ viewTraitStore: inout _ViewTraitStore)
 }
 
-@frozen
+@frozen public struct _TraitWritingModifier<Trait>: ViewModifier, _TraitWritingModifierProtocol
-public struct _TraitWritingModifier<Trait>: ViewModifier, _TraitWritingModifierProtocol
   where Trait: _ViewTraitKey
 {
   public let value: Trait.Value
@@ -41,14 +40,6 @@ public struct _TraitWritingModifier<Trait>: ViewModifier, _TraitWritingModifierP
   public func modifyViewTraitStore(_ viewTraitStore: inout _ViewTraitStore) {
     viewTraitStore.insert(value, forKey: Trait.self)
   }
-
-  public static func _makeView(_ inputs: ViewInputs<_TraitWritingModifier<Trait>>)
-    -> ViewOutputs
-  {
-    var store = inputs.traits ?? .init()
-    store.insert(inputs.content.value, forKey: Trait.self)
-    return .init(inputs: inputs, traits: store)
-  }
 }
 
 extension ModifiedContent: _TraitWritingModifierProtocol

Sources/TokamakCore/ViewTraits/_ViewTraitStore.swift

@@ -16,21 +16,21 @@
 //
 
 public struct _ViewTraitStore {
-  public var values = [ObjectIdentifier: Any]()
+  public var values = [String: Any]()
 
-  public init(values: [ObjectIdentifier: Any] = [:]) {
+  public init(values: [String: Any] = [:]) {
     self.values = values
   }
 
   public func value<Key>(forKey key: Key.Type = Key.self) -> Key.Value
     where Key: _ViewTraitKey
   {
-    values[ObjectIdentifier(key)] as? Key.Value ?? Key.defaultValue
+    values[String(reflecting: key)] as? Key.Value ?? Key.defaultValue
   }
 
   public mutating func insert<Key>(_ value: Key.Value, forKey key: Key.Type = Key.self)
     where Key: _ViewTraitKey
   {
-    values[ObjectIdentifier(key)] = value
+    values[String(reflecting: key)] = value
   }
 }

Sources/TokamakCore/Views/AnyView.swift

@@ -40,8 +40,6 @@ public struct AnyView: _PrimitiveView {
    */
   let bodyType: Any.Type
 
-  let visitChildren: (ViewVisitor, Any) -> ()
-
   public init<V>(_ view: V) where V: View {
     if let anyView = view as? AnyView {
       self = anyView
@@ -54,14 +52,8 @@ public struct AnyView: _PrimitiveView {
       self.view = view
       // swiftlint:disable:next force_cast
       bodyClosure = { AnyView(($0 as! V).body) }
-      // swiftlint:disable:next force_cast
-      visitChildren = { $0.visit($1 as! V) }
     }
   }
-
-  public func _visitChildren<V>(_ visitor: V) where V: ViewVisitor {
-    visitChildren(visitor, view)
-  }
 }
 
 public func mapAnyView<T, V>(_ anyView: AnyView, transform: (V) -> T) -> T? {