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https://github.com/walteh/swift-err
swift macros and other error related helper code 🫡
https://github.com/walteh/swift-err
error-handling errors guard swift swiftui
Last synced: 6 days ago
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swift macros and other error related helper code 🫡
- Host: GitHub
- URL: https://github.com/walteh/swift-err
- Owner: walteh
- License: apache-2.0
- Created: 2024-07-16T12:08:42.000Z (6 months ago)
- Default Branch: main
- Last Pushed: 2024-11-02T22:24:51.000Z (2 months ago)
- Last Synced: 2024-11-09T20:18:44.148Z (2 months ago)
- Topics: error-handling, errors, guard, swift, swiftui
- Language: Swift
- Homepage:
- Size: 92.8 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# swift-err
swift-err is a Swift package that provides convenient error handling macros for Swift projects, allowing for more expressive and type-safe error handling.
## Features
- `@err` function macro to access thrown errors in guard else statements
- `@err_traced` includes trace information in thrown errors (file, line, function)
- Works with any function that can throw, including async functions
## Example
```swift
@err
func throwsExample() throws async -> String {
guard let result = try await someThrowingFunction() else {
throw err // "err" is the error thrown by someThrowingFunction
}
return result
}
@err
func resultExample() async -> Result {
guard let result = await someResultFunction().get() else {
return .failure(err) // "err" is the error thrown by someResultFunction
}
return .success(result)
}
```
## Installation
Add the following dependency to your `Package.swift` file:
```swift
.package(url: "https://github.com/walteh/swift-err.git", branch: "main")
```
Then, add "Err" to your target's dependencies:
```swift
.target(name: "YourTarget", dependencies: ["Err"]),
```
## Usage
### Basic Error Handling
Use the `@err` macro to simplify error handling in your functions:
```swift
// Without @err macro
func resultWithoutErrMacro() async -> Result {
guard let res = try? await myThrowingAsyncFunc(12) else {
// ⚠️ We have no idea what the error is
return .failure(UnknownError())
}
return .success("\(res)")
}
// With @err macro
@err
func resultWithErrMacro() async -> Result {
guard let res = try await myThrowingAsyncFunc(12) else {
// ✅ "err" is the error thrown by myThrowingAsyncFunc
switch err {
case is ValidBusinessError:
return .success("operation already completed")
default:
return .failure(err) // or "throw err" if you want to rethrow
}
}
return .success("\(res)")
}
```
### Traced Error Handling
For more detailed error tracing, use the `@err_traced` macro. This wraps the error with the location (file, line, and function) where the error was triggered.
```swift
@err_traced
func tracedExample() throws -> String {
guard let result = try someThrowingFunction() else {
throw err // This error will include trace information
}
return result
}
```
## How It Works
The `@err` and `@err_traced` macros expand to code that captures the error from throwing expressions. Here's a simplified view of what the macro expansion looks like:
```swift
// Original code with @err macro
@err
func example() throws -> String {
guard let result = try someThrowingFunction() else {
throw err
}
return result
}
func example() throws -> String {
guard let result = someResultFunction().get() else {
throw err
}
return result
}
// Expanded code (simplified)
func example() throws -> String {
var ___err: Error? = nil
guard let result = Result.___err___create(catching: {
try someThrowingFunction()
}).___to(&___err) else {
let err = ___err!
throw err
}
return result
}
```
This expansion allows you to use `err` in your guard statements to access the thrown error, enabling more expressive error handling.
## Testing
The package includes comprehensive unit tests. Run the tests using:
```bash
swift test
```
## Requirements
- Swift 6.0+
## License
This project is licensed under the [Apache License 2.0](LICENSE).
## Contributing
Contributions are welcome! Please feel free to submit a Pull Request.