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November 22, 2017 22:34
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facile-it/Monads test
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| import Monads | |
| func test() { | |
| typealias DeferredResult<T> = Deferred<Result<T, String>> | |
| typealias AsyncResult<T> = Effect<DeferredResult<T>> | |
| struct User { | |
| var name: String | |
| var dateOfBirth: String | |
| } | |
| struct UserRepository { | |
| let user1 = User(name: "Ricardo", dateOfBirth: "01/05/1992") | |
| func getUserByName(name: String) -> AsyncResult<User> { | |
| return AsyncResult<User>.init { () -> Deferred<Result<User, String>> in | |
| return DeferredResult.init(completion: { (completion) in | |
| print("Inside async result") | |
| if(name == "Ricardo"){ | |
| //Async: Simulates retrieving the user from DB | |
| DispatchQueue.main.async { | |
| completion(Result.success(self.user1)) | |
| } | |
| } else { | |
| //Async: Simulates trying to retrieve the user from DB | |
| DispatchQueue.main.async { | |
| print("inside async result's async queue") | |
| completion(Result.failure("User not exists")) | |
| } | |
| } | |
| }) | |
| } | |
| } | |
| } | |
| let userRepository = UserRepository() | |
| print("BEFORE CREATING async result") | |
| let userAsyncResult = userRepository.getUserByName(name: "Ricardo") | |
| print("AFTER CREATING async result") | |
| let upperCasedAsyncResult = userAsyncResult.mapTT { (user) -> User in | |
| let resultUser = User(name: user.name.uppercased(), dateOfBirth: user.dateOfBirth) | |
| return resultUser | |
| } | |
| //Impure part: Execute side effects | |
| let deferredResult = upperCasedAsyncResult.run() | |
| deferredResult.run { (userResult) in | |
| userResult.run( | |
| ifSuccess: {printUser($0)}, | |
| ifFailure: {print($0)}, | |
| ifCancel: {print("cancelled")}) | |
| } | |
| func printUser(_ user: User) -> () { | |
| print(user.name) | |
| } | |
| } |
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Wrapping in
Effectis actually a very interesting strategy to add lazyness to basically everything :DIn FunctionalKit we're making
Future(ex-Deferred) lazy by default.