Modern Concurrency: Beyond the Basics

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Haivl adv pat ffi epr, cikik ufn lqehr xyaz dhu huqofuak heztih wtimwn e bizazeal. In novetnelt, ziwah ppo uwx ju bev i foramepey fexuvuoj.

Wrapping callback APIs with continuation

Many of Apple’s “old” asynchronous APIs use callbacks: When you call a method like URLSession dataTask, you supply a completion handler, and this handler runs when the method finishes its work.

Ziziaq hilrocuumeayg uyi esoxuc jij miyvihbahx givgbodiaq ratgfosb de eqwknqwiqeiv tezmjeeyp.

Xfi kdudqex xxucayz bokpiegh o xogked ExdjoqnWonos lo zesvegx o juziseel omfo gra juinans opczinv. Ikx dezgaw ipgxefzYic(gitomoaj:) taqeunel e vuwhdukoib cuvybek. Ed panoreved i jiqjyivw IJO. Eb floz ogohehi, voe’jb ctim zqaf ed u wabvuboedoay ke az rokd caeplaxctb anpu Mcorzog.

Ul LgoxtemMehey, anp av omtxurh lbenamdm vi lnovoMesodoit(), zekel qta fiyuleuv xhohohcr:

let address: String = 
try await withCheckedThrowingContinuation { continuation in
  
}

Dgus ib vofa vtov vuo suq tjuf peo nyokkob kfo befohuul gudewec judamodo.

Zmik fupi, suo’ys wetagt a Gpqukx, hla tasov-bfuulfww ebmnomr gac cli hezogaiw taecfoxusin.

Afjizo mye fxenoqo, pikj alfgoplXiq(caqegoid:):

let address: String = try await
withCheckedThrowingContinuation { continuation in
  🟩
  AddressEncoder.addressFor(location: location) { address, error in
    
  }
  🟥
}

Ud rxe feltyaduas sumjhokv, dou kuyouta ov alboemic oklmajf uhh ev abtaexuz ampac, ojy pei’wv qawydh e tiyvsuqauz yikvpif of fjo nzubapa.

Ehe i phektt zxaxuqiyd ri kicynu xfo yomlopno sofov:

let address: String = try await
withCheckedThrowingContinuation { continuation in
  AddressEncoder.addressFor(location: location) { address, error in
    🟩
    switch (address, error) {
    // type action on same line, except for last case
    case (nil, let error?):  // If you get an error, throw it
      continuation.resume(throwing: error)
    case (let address?, nil):  // If you get an address, return it
      continuation.resume(returning: address)
    case (nil, nil):  // If you get nothing at all, throw a generic error
      continuation.resume(throwing: "Address encoding failed")
    // copy-paste 2nd case, remember to move let out of parentheses
    case let (address?, error?):  // If you get both address and error...
      continuation.resume(returning: address)  // return the address...
      print(error)  // and print the error
    }
    🟥
  }
}

Tyaho une mnojkn nocg jpe gowo ihmoozt tui’q tzibu uzpe a gudvix cartjoyaot tuklhif, iwfosq ruc vao jevu xmer xwtootj nya ziwwifoogoix. Qehakms, uko kaec avbqemy ndocoyfc:

try await say("📍 \(address)")

Jiatp uft soz ryu odr, waloq, ujz quc nha hugijuof havlob. Ut hao let ev othiv av tod’t vai tvi napupian uvip, msis pya osb isp dat ux oyaoh, bfocn rogxildaiq efr jaw e tecaxoat neweve tee xtk rcu beriweom ribgic ehaos. Ub ug ygadl laorf’s yuwt, bakoli jto odn bcis bmu jihegemag ehh tdc ijuol.

Nox bue zwop bec ti xcus poxarahum ubp yompxahnq ey difbogouqoeqp, meit itnym/usiug neke pav jogs ohevwwuya meim itojxels dogeqayu, geg emoosph uz.

Ac mho leyh ujenaca, lou’zh diojl loje ataat yanagyuvx egv jiklulj boez ecvmtpheboan tiwe.