neo-swift

Modern Swift (5.0+) Expert Skill

Trigger On

• The user asks to write, debug, refactor, or review Swift code.
• The project directory contains *.swift, Package.swift, or *.xcodeproj.
• Development involves iOS (SwiftUI/UIKit), macOS, or Server-side Swift (Vapor).
• Code modernization is needed (e.g., migrating to Structured Concurrency or Swift 6 language mode).

Workflow

1. Perceive (Version Awareness):
   • Identify the Swift version (e.g., check Package.swift or build settings).
   • Determine the platform (SwiftUI vs UIKit, Server vs App).
   • Assess dependency management (Swift Package Manager, CocoaPods).
2. Reason (Planning Phase):
   • Evaluate the use of modern syntax (e.g., async/await, Result, @propertyWrapper).
   • Decide on memory management strategies (ARC, weak/unowned).
   • For UI tasks, prioritize SwiftUI for modern apps or UIKit for legacy support.
3. Act (Execution Phase):
   • Write swifty, concise code following Apple's API Design Guidelines.
   • Implement type-safe and protocol-oriented solutions.
   • Leverage Structured Concurrency (Task, async let) for asynchronous operations.
4. Validate (Standard Validation):
   • Check for memory leaks (retain cycles) using capture lists.
   • Verify Swift 6 concurrency safety (data race detection).
   • Ensure naming conventions follow the standard lowercamelCase for members and PascalCase for types.

Feature Roadmap (Swift 5.0 - 6+)

Swift 5.0 - 5.4 (Foundation)

• Result Type: Standardized error handling.
• Property Wrappers: Encapsulating property logic (e.g., @Published).
• Opaque Types: Hiding implementation details (some View).
• Result Builders: DSL support for SwiftUI.

Swift 5.5 - 5.10 (Modern Concurrency)

• Async/Await: Linear asynchronous code.
• Actors: Thread-safe state isolation.
• Distributed Actors: Communicating across processes.
• Non-copyable Types: Explicit control over object ownership.

Swift 6+ (Safety & Performance)

• Full Data Isolation: Compile-time data race prevention.
• Typed Throws: Explicitly defining error types.
• Embedded Swift: Running Swift on restricted environments.

Coding Standards

• Conciseness: Use trailing closures and shorthand argument names where appropriate.
• Safety: Prefer if let or guard let over force unwrapping (!).
• Purity: Prefer struct (Value Types) over class (Reference Types) for data models.
• Concurrency: Avoid Thread.sleep or legacy completion handlers; use structured concurrency.

Deliver

• Version-Optimized Code: Provide code using the best features of the target Swift version.
• SwiftUI/UIKit Insights: Recommend patterns based on the UI framework used.
• Concurrency Migration: Provide strategies for moving to Swift 6 strict concurrency checks.

Validate

• Ensure code compiles without warnings in the target Swift version.
• Validate that closure capture lists correctly handle object lifecycles.
• Confirm that error handling uses the do-catch or throws patterns correctly.

Documentation

Official References

• Swift API Design Guidelines
• The Swift Programming Language Guide

Internal References

• Swift Coding Style and Naming Conventions
• Swift Anti-Patterns and Best Practices
• Modern Swift Patterns Guide