swift-expert

Name: swift-expert
Author: Jeffallan

11kstars971forks

How to install swift-expert?

jeffallan/claude-skills/swift-expert

$npx -y skills add Jeffallan/claude-skills --skill swift-expert

Installs into the current project.

Summary

Builds iOS/macOS/watchOS/tvOS applications, implements SwiftUI views and state management, designs protocol-oriented architectures, handles async/await concurrency, implements actors for thread safety, and debugs Swift-specific issues. Use when building iOS/macOS applications wit

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SKILL.md

1	# Swift Expert
2
3	## Core Workflow
4
5	1. Architecture Analysis - Identify platform targets, dependencies, design patterns
6	2. Design Protocols - Create protocol-first APIs with associated types
7	3. Implement - Write type-safe code with async/await and value semantics
8	4. Optimize - Profile with Instruments, ensure thread safety
9	5. Test - Write comprehensive tests with XCTest and async patterns
10
11	> Validation checkpoints: After step 3, run `swift build` to verify compilation. After step 4, run `swift build -warnings-as-errors` to surface actor isolation and Sendable warnings. After step 5, run `swift test` and confirm all async tests pass.
12
13	## Reference Guide
14
15	Load detailed guidance based on context:
16
17	\| Topic \| Reference \| Load When \|
18	\|-------\|-----------\|-----------\|
19	\| SwiftUI \| `references/swiftui-patterns.md` \| Building views, state management, modifiers \|
20	\| Concurrency \| `references/async-concurrency.md` \| async/await, actors, structured concurrency \|
21	\| Protocols \| `references/protocol-oriented.md` \| Protocol design, generics, type erasure \|
22	\| Memory \| `references/memory-performance.md` \| ARC, weak/unowned, performance optimization \|
23	\| Testing \| `references/testing-patterns.md` \| XCTest, async tests, mocking strategies \|
24
25	## Code Patterns
26
27	### async/await — Correct vs. Incorrect
28
29	```swift
30	// ✅ DO: async/await with structured error handling
31	func fetchUser(id: String) async throws -> User {
32	let url = URL(string: "https://api.example.com/users/\(id)")!
33	let (data, _) = try await URLSession.shared.data(from: url)
34	return try JSONDecoder().decode(User.self, from: data)
35	}
36
37	// ❌ DON'T: mixing completion handlers with async context
38	func fetchUser(id: String) async throws -> User {
39	return try await withCheckedThrowingContinuation { continuation in
40	// Avoid wrapping existing async APIs this way when a native async version exists
41	legacyFetch(id: id) { result in
42	continuation.resume(with: result)
43	}
44	}
45	}
46	```
47
48	### SwiftUI State Management
49
50	```swift
51	// ✅ DO: use @Observable (Swift 5.9+) for view models
52	@Observable
53	final class CounterViewModel {
54	var count = 0
55	func increment() { count += 1 }
56	}
57
58	struct CounterView: View {
59	@State private var vm = CounterViewModel()
60
61	var body: some View {
62	VStack {
63	Text("\(vm.count)")
64	Button("Increment", action: vm.increment)
65	}
66	}
67	}
68
69	// ❌ DON'T: reach for ObservableObject/Published when @Observable suffices
70	class LegacyViewModel: ObservableObject {
71	@Published var count = 0 // Unnecessary boilerplate in Swift 5.9+
72	}
73	```
74
75	### Protocol-Oriented Architecture
76
77	```swift
78	// ✅ DO: define capability protocols with associated types
79	protocol Repository<Entity> {
80	associatedtype Entity: Identifiable
81	func fetch(id: Entity.ID) async throws -> Entity
82	func save(_ entity: Entity) async throws
83	}
84
85	struct UserRepository: Repository {
86	typealias Entity = User
87	func fetch(id: UUID) async throws -> User { /* … */ }
88	func save(_ user: User) async throws { /* … */ }
89	}
90
91	// ❌ DON'T: use classes as base types when a protocol fits
92	class BaseRepository { // Avoid class inheritance for shared behavior
93	func fetch(id: UUID) async throws -> Any { fatalError("Override required") }
94	}
95	```
96
97	### Actor for Thread Safety
98
99	```swift
100	// ✅ DO: isolate mutable shared state in an actor
101	actor ImageCache {
102	private var cache: [URL: UIImage] = [:]
103
104	func image(for url: URL) -> UIImage? { cache[url] }
105	func store(_ image: UIImage, for url: URL) { cache[url] = image }
106	}
107
108	// ❌ DON'T: use a class with manual locking
109	class UnsafeImageCache {
110	private var cache: [URL: UIImage] = [:]
111	private let lock = NSLock() // Error-prone; prefer actor isolation
112	func image(for url: URL) -> UIImage? {
113	lock.lock(); defer { lock.unlock() }
114	return cache[url]
115	}
116	}
117	```
118
119	## Constraints
120
121	### MUST DO
122	- Use type hints and inference appropriately
123	- Follow Swift API Design Guidelines
124	- Use `async/await` for asynchronous operations (see pattern above)
125	- Ensure `Sendable` compliance for concurrency
126	- Use value types (`struct`/`enum`) by default
127	- Document APIs with markup comments (`/// …`)
128	- Use prope

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6 picks

Type

swift-expert

11kstars971forks

View on GitHub

How to install swift-expert?

jeffallan/claude-skills/swift-expert

$npx -y skills add Jeffallan/claude-skills --skill swift-expert

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# Swift Expert
2
3	## Core Workflow
4
5	1. Architecture Analysis - Identify platform targets, dependencies, design patterns
6	2. Design Protocols - Create protocol-first APIs with associated types
7	3. Implement - Write type-safe code with async/await and value semantics
8	4. Optimize - Profile with Instruments, ensure thread safety
9	5. Test - Write comprehensive tests with XCTest and async patterns
10
11	> Validation checkpoints: After step 3, run `swift build` to verify compilation. After step 4, run `swift build -warnings-as-errors` to surface actor isolation and Sendable warnings. After step 5, run `swift test` and confirm all async tests pass.
12
13	## Reference Guide
14
15	Load detailed guidance based on context:
16
17	\| Topic \| Reference \| Load When \|
18	\|-------\|-----------\|-----------\|
19	\| SwiftUI \| `references/swiftui-patterns.md` \| Building views, state management, modifiers \|
20	\| Concurrency \| `references/async-concurrency.md` \| async/await, actors, structured concurrency \|
21	\| Protocols \| `references/protocol-oriented.md` \| Protocol design, generics, type erasure \|
22	\| Memory \| `references/memory-performance.md` \| ARC, weak/unowned, performance optimization \|
23	\| Testing \| `references/testing-patterns.md` \| XCTest, async tests, mocking strategies \|
24
25	## Code Patterns
26
27	### async/await — Correct vs. Incorrect
28
29	```swift
30	// ✅ DO: async/await with structured error handling
31	func fetchUser(id: String) async throws -> User {
32	let url = URL(string: "https://api.example.com/users/\(id)")!
33	let (data, _) = try await URLSession.shared.data(from: url)
34	return try JSONDecoder().decode(User.self, from: data)
35	}
36
37	// ❌ DON'T: mixing completion handlers with async context
38	func fetchUser(id: String) async throws -> User {
39	return try await withCheckedThrowingContinuation { continuation in
40	// Avoid wrapping existing async APIs this way when a native async version exists
41	legacyFetch(id: id) { result in
42	continuation.resume(with: result)
43	}
44	}
45	}
46	```
47
48	### SwiftUI State Management
49
50	```swift
51	// ✅ DO: use @Observable (Swift 5.9+) for view models
52	@Observable
53	final class CounterViewModel {
54	var count = 0
55	func increment() { count += 1 }
56	}
57
58	struct CounterView: View {
59	@State private var vm = CounterViewModel()
60
61	var body: some View {
62	VStack {
63	Text("\(vm.count)")
64	Button("Increment", action: vm.increment)
65	}
66	}
67	}
68
69	// ❌ DON'T: reach for ObservableObject/Published when @Observable suffices
70	class LegacyViewModel: ObservableObject {
71	@Published var count = 0 // Unnecessary boilerplate in Swift 5.9+
72	}
73	```
74
75	### Protocol-Oriented Architecture
76
77	```swift
78	// ✅ DO: define capability protocols with associated types
79	protocol Repository<Entity> {
80	associatedtype Entity: Identifiable
81	func fetch(id: Entity.ID) async throws -> Entity
82	func save(_ entity: Entity) async throws
83	}
84
85	struct UserRepository: Repository {
86	typealias Entity = User
87	func fetch(id: UUID) async throws -> User { /* … */ }
88	func save(_ user: User) async throws { /* … */ }
89	}
90
91	// ❌ DON'T: use classes as base types when a protocol fits
92	class BaseRepository { // Avoid class inheritance for shared behavior
93	func fetch(id: UUID) async throws -> Any { fatalError("Override required") }
94	}
95	```
96
97	### Actor for Thread Safety
98
99	```swift
100	// ✅ DO: isolate mutable shared state in an actor
101	actor ImageCache {
102	private var cache: [URL: UIImage] = [:]
103
104	func image(for url: URL) -> UIImage? { cache[url] }
105	func store(_ image: UIImage, for url: URL) { cache[url] = image }
106	}
107
108	// ❌ DON'T: use a class with manual locking
109	class UnsafeImageCache {
110	private var cache: [URL: UIImage] = [:]
111	private let lock = NSLock() // Error-prone; prefer actor isolation
112	func image(for url: URL) -> UIImage? {
113	lock.lock(); defer { lock.unlock() }
114	return cache[url]
115	}
116	}
117	```
118
119	## Constraints
120
121	### MUST DO
122	- Use type hints and inference appropriately
123	- Follow Swift API Design Guidelines
124	- Use `async/await` for asynchronous operations (see pattern above)
125	- Ensure `Sendable` compliance for concurrency
126	- Use value types (`struct`/`enum`) by default
127	- Document APIs with markup comments (`/// …`)
128	- Use prope

People who liked this also viewed

6 picks

Type