Landmarks: Extending horizontal scrolling under a sidebar or inspector

At a glance

Project structure

Source bundle/
└── Landmarks/
    └── Landmarks/
        ├── LandmarksApp.swift
        └── Views/
            ├── Landmarks/
            │   ├── Landmark Detail/
            │   │   ├── LandmarkDetailInspectorView.swift
            │   │   ├── LandmarkDetailView.swift
            │   │   └── LandmarkDetailMapView.swift
            │   └── Landmarks View/
            │       └── LandmarksView.swift
            ├── Badges/
            │   └── BadgesView.swift
            ├── Collections/
            │   ├── Collections/
            │   │   ├── CollectionsView.swift
            │   │   └── CollectionListItemView.swift
            │   └── Collection Detail/
            │       ├── CollectionDetailDisplayView.swift
            │       ├── CollectionDetailEditingView.swift
            │       └── CollectionDetailView.swift
            └── Landmarks Split View/
                └── LandmarksSplitView.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 50 source declaration(s).

Overall architecture

flowchart LR
    N1["LandmarksApp"]
    N2["LandmarksSplitView"]
    N3["SwiftUI APIs"]
    N1 --> N2
    N2 --> N3

Reference code

Landmarks/Landmarks/LandmarksApp.swift:11 — architecture anchor

@main
struct LandmarksApp: App {
    // ...
}

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 SwiftUI.

Ownership and state

classDiagram
    LandmarksApp *-- ModelData : modelData
    Constants *-- CGFloat : cornerRadius
    Constants *-- CGFloat : leadingContentInset
    Constants *-- CGFloat : standardPadding

Ownership evidence

Landmarks/Landmarks/LandmarksApp.swift:14 — stored dependency or nearest verified ownership anchor

@main
struct LandmarksApp: App {
    // ...
    @State private var modelData = ModelData()
    // ...
}

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.

Class and protocol design

Landmarks/Landmarks/LandmarksApp.swift:12 — representative type boundary

struct LandmarksApp: App {
    // ...
}

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

Access control

Reference code

Landmarks/Landmarks/LandmarksApp.swift:14 — representative boundary

@main
struct LandmarksApp: App {
    // ...
    @State private var modelData = ModelData()
    // ...
}

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

Naming conventions

• Types: App: LandmarksApp; View: BadgeProgressView, BadgesView, CollectionDetailDisplayView, CollectionDetailEditingView, CollectionDetailView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: body, showsBadges.
• Files: Landmarks/Landmarks/LandmarksApp.swift, Landmarks/Landmarks/Views/Landmarks/Landmark Detail/LandmarkDetailInspectorView.swift, Landmarks/Landmarks/Views/Badges/BadgesView.swift, Landmarks/Landmarks/Views/Collections/Collections/CollectionsView.swift, Landmarks/Landmarks/Views/Landmarks/Landmark Detail/LandmarkDetailView.swift, Landmarks/Landmarks/Views/Landmarks/Landmarks View/LandmarksView.swift.

Architecture takeaways

• LandmarksApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, MapKit, CoreLocation, CoreTransferable 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