Hello World

At a glance

Project structure

Source bundle/
├── World/
│   ├── WorldApp.swift
│   ├── Model/
│   │   └── ViewModel.swift
│   ├── Systems/
│   │   ├── TraceSystem.swift
│   │   └── RotationSystem.swift
│   ├── Globe/
│   │   └── GlobeControls.swift
│   ├── Solar System/
│   │   └── SolarSystem.swift
│   ├── Modules/
│   │   └── TableOfContents.swift
│   ├── Orbit/
│   │   └── OrbitModule.swift
│   ├── Entities/
│   │   └── EarthEntity+Configuration.swift
│   └── RealityViews/
│       └── OpenWindow.swift
└── Packages/
    └── WorldAssets/
        └── Sources/
            └── WorldAssets/
                ├── SunPositionSystem.swift
                └── WorldAssets.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 4 project/configuration file(s) and 53 source declaration(s).

Overall architecture

flowchart LR
    N1["WorldApp"]
    N2["ItemView"]
    N3["ViewModel"]
    N4["RotationSystem"]
    N5["SwiftUI / RealityKit APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4
    N4 --> N5

Reference code

World/WorldApp.swift:12 — architecture anchor

@main
struct WorldApp: App {
    // ...
    @State private var model = ViewModel()
    // ...
}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into visionOS.

Ownership and state

classDiagram
    ViewModel *-- Array : navigationPath
    ViewModel *-- String : titleText
    ViewModel *-- Bool : isTitleFinished
    ViewModel *-- String : finalTitle

Ownership evidence

World/Model/ViewModel.swift:20 — stored dependency or nearest verified ownership anchor

@Observable
class ViewModel {
    // ...
    var navigationPath: [Module] = []
    // ...
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

Packages/WorldAssets/Sources/WorldAssets/WorldAssets.swift:48 — representative execution boundary

public func entity(named name: String) async -> Entity? {
    // ...
        return try await Entity(named: name, in: worldAssetsBundle)
    // ...
}

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

World/WorldApp.swift:13 — representative type boundary

@main
struct WorldApp: App {
    // ...
    @State private var model = ViewModel()
    // ...
}

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

Packages/WorldAssets/Sources/WorldAssets/SunPositionSystem.swift:15 — representative boundary

    public init(_ sunAngle: Float) {
        sunAngleRadians = sunAngle
    }

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Main application flow

sequenceDiagram
    participant EarthEntity
    participant WorldAssets
    participant satellites
    participant SatelliteEntity
    EarthEntity->>WorldAssets: entity()
    EarthEntity->>WorldAssets: entity()
    EarthEntity->>satellites: addChild()
    EarthEntity->>SatelliteEntity: SatelliteEntity()

Reference code

World/Entities/EarthEntity.swift:70 — init()

    init(
        configuration: Configuration,
        satelliteConfiguration: [SatelliteEntity.Configuration],
        moonConfiguration: SatelliteEntity.Configuration?
    ) async {
        // ...
        super.init()
        guard let earth = await WorldAssets.entity(named: configuration.isCloudy ? "Earth" : "Globe"),
              let pole = await WorldAssets.entity(named: "Pole") else { return }
        self.earth = earth
        self.pole = pole
        for configuration in satelliteConfiguration {
            await satellites.addChild(SatelliteEntity(configuration))
        }
        self.addChild(equatorialPlane)
        equatorialPlane.addChild(earth)
        earth.addChild(pole)
        moon = await SatelliteEntity(.orbitMoonDefault)
        self.addChild(moon)
        equatorialPlane.addChild(satellites)
        update(
            configuration: configuration,
            satelliteConfiguration: satelliteConfiguration,
            moonConfiguration: moonConfiguration,
            animateUpdates: false)
    }

Naming conventions

• Types: App: WorldApp; Component: RotationComponent, SunPositionComponent, TraceComponent; System: RotationSystem, SolarSystem, SunPositionSystem, TraceSystem; View: ItemView; ViewModel: ViewModel.
• Protocols: no local protocol declaration in the scanned source.
• Methods: update, getModelDescendents, setSunPosition, addPosition, generateIndices, makeTraceModel, defaultValue.
• Files: World/WorldApp.swift, World/Model/ViewModel.swift, Packages/WorldAssets/Sources/WorldAssets/SunPositionSystem.swift, World/Systems/TraceSystem.swift, World/Systems/RotationSystem.swift, World/Globe/GlobeControls.swift.

Architecture takeaways

• WorldApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, RealityKit, WorldAssets, PackageDescription through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation