ole

// Excerpt from `SwiftUI.framework/Modules/SwiftUI.swiftmodule/arm64-apple-ios.swiftinterface`
// in Xcode 14.0b1
//
// This is how any `Layout`-conforming type becomes a container view
// when it's used with a `@ViewBuilder` closure.
@available(iOS 16.0, macOS 13.0, tvOS 16.0, watchOS 9.0, *)
extension SwiftUI.Layout {
  @_alwaysEmitIntoClient public func callAsFunction<V>(@SwiftUI.ViewBuilder _ content: () -> V) -> some SwiftUI.View where V : SwiftUI.View {
        return _VariadicView.Tree(
            root: _LayoutRoot(self), content: content())

ole

// I learned about `#if canImport(module, _version: x.y)` from Tony Allevato:
// https://forums.swift.org/t/pitch-sdk-conditional-code/52642/4
//
// Does this work reliably? I have no idea!
// I have only done some quick experiments in a playground.
//
// The Foundation version in Xcode 14.0b1 is:
// - in iOS's Foundation.swiftinterface: 1932.104
// - in macOS's Foundation.swiftinterface: 1932.401
//

ole

import SwiftUI

extension LocalizedStringKey.StringInterpolation {
    /// String interpolation support for links in Text.
    ///
    /// Usage:
    ///
    ///     let url: URL = …
    ///     Text("\("Link title", url: url)")
    mutating func appendInterpolation(_ linkTitle: String, link url: URL) {

ole

import Dispatch

@globalActor
final actor MyMainActor {
  // Don’t allow others to create instances
  private init() {}

  // Requirements from the implicit GlobalActor conformance
  typealias ActorType = MyMainActor

ole

// A heterogeneous dictionary with strong types in Swift, https://oleb.net/2022/heterogeneous-dictionary/
// Ole Begemann, April 2022

/// A key in a `HeterogeneousDictionary`.
public protocol HeterogeneousDictionaryKey {
  /// The "namespace" the key belongs to. Every `HeterogeneousDictionary` has its associated domain,
  /// and only keys belonging to that domain can be stored in the dictionary.
  associatedtype Domain
  /// The type of the values that can be stored under this key in the dictionary.
  associatedtype Value

ole

// This is the code for https://forums.swift.org/t/communicating-between-two-concurrent-tasks/54240

import _Concurrency

actor Buffer {
  var elements: [Int] = []
  private var isNotEmpty: CheckedContinuation<Void, Never>? = nil

  deinit {
    // TODO: If the continuation is not nil,

ole

import _Concurrency

actor Channel<Output> {
  private var conditionVar: CheckedContinuation<Output, Never>? = nil

  deinit {
    // TODO: if conditionVar != nil, resume it by throwing `CancellationError()`?
  }

  /// If there's no receiver, the sent value will be lost.

ole

// A view that can flip between its "front" and "back" side.
//
// Animation implementation based on:
// Chris Eidhof, Keyframe animations <https://gist.github.com/chriseidhof/ea0e435197f550b195bb749f4777bbf7>

import SwiftUI

// MARK: - Chris's keyframe animation design

struct Keyframe<Data: Animatable> {

ole

// 1. Run on iPad simulator in landscape (= two-column navigation view).
// 2. Drill down to level 3
// 3. Observe console output.
//
// Result with .navigationViewStyle(.stack) (as expected):
//   Level 1: drilledDown=false
//   Level 1: drilledDown=true
//   Level 2: drilledDown=false
//   Level 2: drilledDown=true
//   Level 3: drilledDown=false

ole

import SwiftUI

struct ContentView: View {
  @State var horizontal: Bool = true
  @Namespace var namespace

  var body: some View {
    VStack(spacing: 40) {
      if horizontal {
        HStack { items }