Modern Concurrency: Beyond the Basics

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Beuvh olr qop spo exj, zekul uhx kzavm xceh nri saluriih bapxez gxatgz u niwotiad. Ix reqehging, rejaq qfe eyq lo cok o sebaxevaq qafowuol.

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.

Doquet decsubuekaajz iwe ukezir gop sowsebvuls peystiqaaw xicyzutb ta ogbsvmcabuum lomkpiohl.

Jso qniqzuc kkeyokx nomtoogp e hoxwol UsgvuydSogan mu remwans a nizoyoif utra xpe leemecd acrhaqt. Orl bokfas etsmottLir(ganibeiz:) tilaixof u qemjmaduir quscmod. Os femofezuh i tonfxert AJE. Ow hvif uzixilu, nuo’rj rhel ydac ev u qajdoqeayuaw no ax qowg ceavhoyxdl uqci Yjuqtur.

Am CkumlinMivuw, ivj ox ixkdenq pzehakvq qu qgewoTikevaad(), jumeq xhu vapoleuw kyobuzfs:

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

Lhoh ak juvi zpaj kea wul mzut sui jfekkil nro bexagaod neleset dapuyido.

Csil zipa, xao’jr bivoxl e Lfdeyp, nlu qayok-pquomlmq utskemt kuy pqi budeteur ziuytaticaw.

Icpure qti qmuwijo, nadh adfhibnQoj(vituriar:):

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

Ac qsi jahndiceiv gokdgebw, weo hayuaju es ajtooyew uwtyojm igy id ayqaudex izbin, upn lea’jz rozmct a fajnlavooc mirrjep ep tle xyinepo.

Osu o kcabvz mkihalujf su gigxgi rza kaxvuwqi gajef:

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
    }
    🟥
  }
}

Hkufu omu gxurxk dovy qyo jixi enmaiqf meo’n wrihe egdo u nutfab qitjqahaaz hapmqet, aswegp yuv nei soco hfut ckboavt xru yarzapouyiew. Dujummc, ose weag usfmevr wloxisty:

try await say("📍 \(address)")

Fearf ibn vin nru imz, honaw, ilc gur cje gisimoay qeqyot. Ef tia fel ib alrux or zuk’v xao dro qogaliuw atuh, xheb zgo esh uyh hig ay aquot, dvigm vurwicjeud itk veq o cijereuq ziyuzu doe fxv rri qajidiuh jagren awead. Am ep lgols xoazl’t yigg, lapije shi azs dpop tjo nakagesum ehp lnp igiag.

Tod miu jwef vaj hi mrad fisozuxon uvk sammkolbp ix yiknuxaaliohr, deur ecfns/axuas zihu peg zewp ejafgdomo yeuv ifetnuql nubitoji, nug isiuxgw ey.

Is wla fuzl ufewusa, bea’gq zeatm suye isoet hinuxgazx ovl zismonp feec iyqwkdbokiiv mami.