Language Introspector

At a glance

Project structure

Source bundle/
└── LanguageIntrospector/
    ├── LanguageIntrospectorApp.swift
    ├── DateFormatterModel.swift
    ├── LanguagesModel.swift
    ├── CharacterDirectionView.swift
    ├── ContentView.swift
    ├── DateComponentsFormatterView.swift
    ├── DateComponentsModel.swift
    ├── DateFormatterView.swift
    ├── DateIntervalFormatterModel.swift
    ├── DateIntervalFormatterView.swift
    ├── DatesView.swift
    └── LanguagesView.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 3 project/configuration file(s) and 34 source declaration(s).

Overall architecture

flowchart LR
    N1["LanguageIntrospectorApp"]
    N2["ContentView"]
    N3["DateComponentsModel"]
    N4["SwiftUI / AppKit APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

LanguageIntrospector/LanguageIntrospectorApp.swift:10 — architecture anchor

@main
struct LanguageIntrospectorApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

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 Foundation.

Ownership and state

classDiagram
    DateFormatterModel *-- Date : sampleDate
    DateFormatterModel o-- DateFormatter : formatter
    DateFormatterModel o-- Style : dateStyle
    DateFormatterModel o-- Style : timeStyle

Ownership evidence

LanguageIntrospector/DateFormatterModel.swift:16 — stored dependency or nearest verified ownership anchor

@MainActor
@Observable class DateFormatterModel {
    // ...
    private let sampleDate: Date
    // ...
}

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

LanguageIntrospector/AppScreen.swift:36 — representative execution boundary

extension AppScreen {
    // ...
    @MainActor
    @ViewBuilder var destination: some View {
        switch self {
        case .languages:
           LanguagesView()
        case .dates:
            DatesView()
        case .measurements:
            MeasurementsView()
        case .names:
            NamesView()
        case .numbers:
            NumbersView()
        }
    }
}

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

LanguageIntrospector/LanguageIntrospectorApp.swift:11 — representative type boundary

@main
struct LanguageIntrospectorApp: App {
    // ...
            ContentView()
    // ...
}

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

Access control

Reference code

LanguageIntrospector/CharacterDirectionView.swift:24 — representative boundary

    private var characterDirectionView: some View {
        // ...
        case .leftToRight:
        // ...
    }

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: LanguageIntrospectorApp; Model: DateComponentsModel, DateFormatterModel, DateIntervalFormatterModel, LanguagesModel, MeasurementsModel; View: CharacterDirectionView, ContentView, DateComponentsFormatterView, DateFormatterView, DateIntervalFormatterView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: lengthIndicator, string, updateFormatter, sortedLanguages.
• Files: LanguageIntrospector/LanguageIntrospectorApp.swift, LanguageIntrospector/DateFormatterModel.swift, LanguageIntrospector/LanguagesModel.swift, LanguageIntrospector/CharacterDirectionView.swift, LanguageIntrospector/ContentView.swift, LanguageIntrospector/DateComponentsFormatterView.swift.

Architecture takeaways

• LanguageIntrospectorApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, AppKit, UIKit 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