https://github.com/pointfreeco/swift-prelude

🎶 A collection of types and functions that enhance the Swift language.
https://github.com/pointfreeco/swift-prelude

functional-programming prelude swift

Last synced: 7 days ago
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🎶 A collection of types and functions that enhance the Swift language.

• Host: GitHub
• URL: https://github.com/pointfreeco/swift-prelude
• Owner: pointfreeco
• License: mit
• Created: 2017-06-15T19:59:50.000Z (over 7 years ago)
• Default Branch: main
• Last Pushed: 2024-07-04T01:04:57.000Z (4 months ago)
• Last Synced: 2024-10-10T22:47:58.031Z (about 1 month ago)
• Topics: functional-programming, prelude, swift
• Language: Swift
• Homepage:
• Size: 271 KB
• Stars: 469
• Watchers: 19
• Forks: 52
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md

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README

        
# swift-prelude

[![Swift 5.1](https://img.shields.io/badge/swift-5.1-ED523F.svg?style=flat)](https://swift.org/download/)

[![CI](https://github.com/pointfreeco/swift-prelude/workflows/CI/badge.svg)](https://actions-badge.atrox.dev/pointfreeco/swift-prelude/goto)

[![@pointfreeco](https://img.shields.io/badge/[email protected]?style=flat)](https://twitter.com/pointfreeco)

A collection of frameworks to enhance the Swift language.

## Stability

This library should be considered experimental. If you find its contents useful, please consider maintaining a fork.

## Installation

```swift

import PackageDescription

let package = Package(

  dependencies: [

    .package(url: "https://github.com/pointfreeco/swift-prelude.git", .branch("main")),

  ]

)

```

## Table of Contents

* [`Prelude`](#prelude)

* [`Either`](#either)

* [`Optics`](#optics)

* [`ValidationSemigroup`](#validationsemigroup)

* [`ValidationNearSemiring`](#validationnearsemiring)

## `Prelude`

A collection of types and functions to build powerful abstractions and enhance the Swift standard library.

## `Either`

A type to express a value that holds one of two other types.

```swift

import Either

let intOrString = Either.left(2)

intOrString

  .bimap({ $0 + 1 }, { $0 + "!" }) // => .left(3)

```

## `Optics`

A `Lens` type and a bridge between the lens world and the Swift key path world.

```swift

import Optics

import Prelude

struct User {

  var id: Int

  var name: String

}

let uppercased: (String) -> String = { $0.uppercased() }

let user = User(id: 1, name: "Blob")

user

  |> \.id .~ 2

  |> \.name %~ uppercased

// => User(2, "BLOB")

```

## `ValidationSemigroup`

The `Validation` type is a type similar to `Result`, except it is given a different applicative instance in the case that `E` is a semigroup. This allows you to accumulate multiple errors into `E` instead of just taking the first error:

```swift

import Prelude

import ValidationSemigroup

struct User { let name: String; let bio: String; let email: String }

let createUser = { name in { bio in { email in User(name: name, bio: bio, email: email) } } }

func validate(name: String) -> Validation<[String], String> {

  return !name.isEmpty

    ? pure(name)

    : .invalid(["Name must be at least 1 character."])

}

func validate(bio: String) -> Validation<[String], String> {

  return bio.count <= 10

    ? pure(bio)

    : .invalid(["Bio must 10 characters or less."])

}

func validate(email: String) -> Validation<[String], String> {

  return email.contains("@")

    ? pure(email)

    : .invalid(["Email must be valid."])

}

let validUser = pure(createUser)

  <*> validate(name: "Blob")

  <*> validate(bio: "I'm a blob")

  <*> validate(email: "[email protected]")

// => .valid(User(name: "Blob", bio: "I'm a blob", email: "[email protected]"))

let invalidUser = pure(createUser)

  <*> validate(name: "Blob")

  <*> validate(bio: "Blobbin around the world")

  <*> validate(email: "blob")

// => .invalid(["Bio must 10 characters or less.", "Email must be valid."])

```

For more information, watch [Stephen Celis’](http://www.twitter.com/stephencelis) [talk](https://www.youtube.com/watch?v=Awva79gjoHY).

## `ValidationNearSemiring`

This `Validation` type is a type similar to `Result` and the above `Validation`, except it is given a different applicative instance in the case that `E` is a `NearSemiring`. This allows you to accumulate errors that describe conditions that hold with both “and” and “or”, e.g. name is required _and_ either email _or_ phone is required.

## License

All modules are released under the MIT license. See [LICENSE](LICENSE) for details.