Future

Swift µframework providing Future<T, Error>

Code Quality Rank: L4

Programming language: Swift

License: MIT License

Tags: Events    

Latest version: v0.0.4

README

Future

Swift µframework providing Future<T, Error>.

This library is inspired by the talk of Javier Soto at SwiftSubmit2015 and the Future implementation in Scala.

And this is using antitypical/Result.

Why we need Future?

Traditional async code

 func requestRepository(repoId: Int64, completion: (Repository?, NSError?) -> Void) {}
 func requestUser(userId: Int64, completion: (User?, NSError?) -> Void) {}

 // get owner info of a given repository
 requestRepository(12345) { repo, error in
    if let repo = repo {
        requestUser(repo.ownerId) { user, error in
           if let user = user {
               // do something
           } else {
               // error handling
           }
        }
    } else {
        // error handling
    }
 }

Code with Future

let future = requestRepository(12345)
        .map { $0.ownerId }
        .flatMap(requestUser)

future.onCompleted { result in
    switch result {
        case .Success(let user):   println(user)
        case .Failure(let error):  println(error)
    }
}

Shorthand by using operator

let future = requestRepository(12345) <^> { $0.ownerId } >>- requestUser

future.onCompleted { result in
    switch result {
        case .Success(let user):   println(user)
        case .Failure(let error):  println(error)
    }
}

Usage

• map <^>

let f = requestUser("nghialv") <^> { $0.id }

f.onSuccess { userId in
    println(userId)
}

• flatMap >>-

let f = searchRepositories("Hakuba") <^> { $0.first!.ownerName } >>- requestUser

f.onComplete { result in
    switch result {
        case .Success(let user):   println(user)
        case .Failure(let error):  println(error)
    }
}

• filter

let e = NSError(domain: "noSuchElement", code: 1, userInfo: nil)
let f1 = searchRepositories("Hakuba")

let f = f1.filter(e){ $0.count > 0 } <^> { $0.first!.ownerName } >>- requestUser

f.onComplete { result in
    switch result {
        case .Success(let user):   println(user)
        case .Failure(let error):  println(error)
    }
}

• andThen

// side-effect
var reposCount = 0

let f1 = searchRepositories("Hakuba")
let f2 = f1.andThen { result in
    switch result {
        case .Success(let repos): reposCount = repos.value.count
        case .Failure(let error): break
    }
}
let f3 = f2 <^> { $0.first!.ownerName } >>- requestUser

f3.onComplete { result in
    switch result {
        case .Success(let user):   println(user)
        case .Failure(let error):  println(error)
    }
}

• recover

• zip

let f1 = searchRepositories("Future")
let f2 = requestUser("nghialv")

let f3 = f1.zip(f2)

f3.onSuccess { repos, user in
    println(repos)
    println(user)
}

• flatten

Installation

• Using Carthage

  • Insert github "nghialv/Future" to your Cartfile
  • Run carthage update

• Using Cocoapods

  • Insert use_frameworks! to your Podfile
  • Insert pod "Future" to your Podfile
  • Run pod install

• Using Submodule

Requirements

• Swift 1.2 (Xcode 6.3 or later)
• iOS 8.0 or later