Swift Patterns

When to use this skill

Use this skill when working on Swift projects (SwiftPM packages, iOS/macOS apps) and you want consistent patterns for concurrency, structure, and safety.

Core patterns

SwiftPM structure

• Package.swift is the source of truth
• keep targets small and focused
• avoid circular dependencies between targets

Concurrency (async/await)

Rules:

• use async/await for IO
• keep cancellation in mind
• avoid blocking work on the main thread

Value types by default

Prefer:

• struct for value semantics
• class when identity/shared mutable state is required

Error handling

• throw typed errors where helpful
• add context at boundaries

Testing

• keep tests deterministic
• prefer unit tests for pure logic

Atlarix tool notes

• Explore: inspect Package.swift and target layout.
• Build: run swift test or Xcode build scripts depending on project.
• Debug: follow crash logs and stack traces; find the first app frame.
• Review: check concurrency correctness and API clarity.

Common mistakes to avoid

• Doing heavy work on the main thread
• Overusing reference types
• Ignoring cancellation

Mini-checklist

• Targets are small and layered
• Concurrency is used correctly
• Tests run reliably