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 iniflet repo = repo {requestUser(repo.ownerId){ user, error iniflet user = user { // do something }else{ // error handling }}}else{ // error handling }}

letfuture=requestRepository(12345).map{ $0.ownerId }.flatMap(requestUser) future.onCompleted{ result inswitch result {case.Success(let user):println(user)case.Failure(let error):println(error)}}

letfuture=requestRepository(12345)<^>{ $0.ownerId }>>- requestUser future.onCompleted{ result inswitch result {case.Success(let user):println(user)case.Failure(let error):println(error)}}

letf=requestUser("nghialv")<^>{ $0.id } f.onSuccess{ userId inprintln(userId)}

letf=searchRepositories("Hakuba")<^>{ $0.first!.ownerName }>>- requestUser f.onComplete{ result inswitch result {case.Success(let user):println(user)case.Failure(let error):println(error)}}

lete=NSError(domain:"noSuchElement", code:1, userInfo:nil)letf1=searchRepositories("Hakuba")letf= f1.filter(e){ $0.count >0}<^>{ $0.first!.ownerName }>>- requestUser f.onComplete{ result inswitch result {case.Success(let user):println(user)case.Failure(let error):println(error)}}

// side-effect varreposCount=0letf1=searchRepositories("Hakuba")letf2= f1.andThen{ result inswitch result {case.Success(let repos): reposCount = repos.value.count case.Failure(let error):break}}letf3= f2 <^>{ $0.first!.ownerName }>>- requestUser f3.onComplete{ result inswitch result {case.Success(let user):println(user)case.Failure(let error):println(error)}}

letf1=searchRepositories("Future")letf2=requestUser("nghialv")letf3= f1.zip(f2) f3.onSuccess{ repos, user inprintln(repos)println(user)}