Cursor rule

1---
2description: "Swift coding style extending common rules"
3globs: ["**/*.swift", "**/Package.swift"]
4alwaysApply: false
5---
6# Swift Coding Style
7 
8> This file extends the common coding style rule with Swift specific content.
9 
10## Formatting
11 
12- **SwiftFormat** for auto-formatting, **SwiftLint** for style enforcement
13- `swift-format` is bundled with Xcode 16+ as an alternative
14 
15## Immutability
16 
17- Prefer `let` over `var` -- define everything as `let` and only change to `var` if the compiler requires it
18- Use `struct` with value semantics by default; use `class` only when identity or reference semantics are needed
19 
20## Naming
21 
22Follow [Apple API Design Guidelines](https://www.swift.org/documentation/api-design-guidelines/):
23 
24- Clarity at the point of use -- omit needless words
25- Name methods and properties for their roles, not their types
26- Use `static let` for constants over global constants
27 
28## Error Handling
29 
30Use typed throws (Swift 6+) and pattern matching:
31 
32```swift
33func load(id: String) throws(LoadError) -> Item {
34    guard let data = try? read(from: path) else {
35        throw .fileNotFound(id)
36    }
37    return try decode(data)
38}
39```
40 
41## Concurrency
42 
43Enable Swift 6 strict concurrency checking. Prefer:
44 
45- `Sendable` value types for data crossing isolation boundaries
46- Actors for shared mutable state
47- Structured concurrency (`async let`, `TaskGroup`) over unstructured `Task {}`
48