https://github.com/miquido/mqtagged

Type distinction for Swift. The project was made by Miquido: https://www.miquido.com/
https://github.com/miquido/mqtagged

Last synced: 5 days ago
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Type distinction for Swift. The project was made by Miquido: https://www.miquido.com/

• Host: GitHub
• URL: https://github.com/miquido/mqtagged
• Owner: miquido
• License: apache-2.0
• Created: 2022-06-29T11:27:51.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2023-08-04T13:18:32.000Z (over 1 year ago)
• Last Synced: 2024-11-09T11:34:55.175Z (2 months ago)
• Language: Swift
• Homepage:
• Size: 16.6 KB
• Stars: 2
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# MQTagged

[![Platforms](https://img.shields.io/badge/platform-iOS%20|%20iPadOS%20|%20macOS-gray.svg?style=flat)]()

[![Swift Package Manager compatible](https://img.shields.io/badge/Swift%20Package%20Manager-compatible-brightgreen.svg)](https://github.com/apple/swift-package-manager)

[![SwiftVersion](https://img.shields.io/badge/Swift-5.6-brightgreen.svg)]()

MQTagged provides a `Tagged` structure which helps differentiating between values of the same type.

## Summary

Let's have an example of a function which authorizes a user based on two string parameters:

```swift

func authorize(_ username: String, _ password: String) {

  ...

}

```

It is possible to call the function with swapped arguments without any compiler warning. Using a `typealias` also does not solves the issue:

```swift

typealias Username = String

typealias Password = String

func authorize(_ username: Username, _ password: Password) {

  ...

}

let username: Username = "[email protected]"

let password: Password = "pa55w0rD"

authorize(username, password)

authorize(password, username) // It's wrong but still compiles.

```

`typealias` doesn't cause compiler warning or error when type names are not matching since resolved type is the same. MQTagged solution to this problem is to use `Tag` type:

```swift

enum UsernameTag {}

enum PasswordTag {}

typealias Username = Tagged

typealias Password = Tagged

func authorize(_ username: Username, _ password: Password) {

  ...

}

```

Now any call with swapped parameters won't compile.

```swift

let username: Username = "[email protected]"

let password: Password = "pa55w0rD"

authorize(username, password)

authorize(password, username) // This won't compile.

```

## Installation

`MQTagged` can be integrated through Swift Package Manager. In your `Package.swift` file add the following `dependency`:

```swift

dependencies: [

  .package(

    url: "https://github.com/miquido/mqtagged.git",

    .upToNextMajor("0.1.0")

  )

]

```

## License

Copyright 2022-2023 Miquido

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.