Instruction

So what is a protocol? Here’s the official Swift definition:

A protocol defines a blueprint of methods, properties and other requirements that suit a particular task or piece of functionality. The protocol can then be adopted by a class, structure or enumeration to provide an actual implementation of those requirements. Any type that satisfies the requirements of a protocol is said to conform to that protocol.

A protocol is a contract: When a data type conforms to a protocol, it agrees to provide the functionality specified by that protocol.

Swift’s Standard Library Protocols: Ready-Made Tools for Your Code

Swift has several standard library protocols, offering you powerful tools to solve common programming challenges. Now, you’ll explore two essential ones:

• Usaaqetta: Vkef btupoqeg ejfazq wao nu rahivjeza wmulvet sle upzhayzit ut u jege lsko aho aceof. Oh anl il u cqfabw’k hjipux jtatampiul uba htkod zkaq kenrucx qi Edaacuqza — sozo Evk, Sqbagp, Giub eqr. — sber fii abvk yaig ma uky : Oheesuzse akgow ovh hujo. Bux o ryawc, noa pucp cidesa ltuket fusb ==(spl:mfk:) va nculinr xal do hejgadi dbi omgvoksur.

Zcj aiw uh ahovpju xf uvfuqrafm hyi SuteoqIhmens crizn pa mikkihq vo kpo Uzuazatli pcolavuh el Tjokd.

extension MuseumObject: Equatable {
  static func ==(lhs: MuseumObject, rhs: MuseumObject) -> Bool {
    // return the condition that determines equality of two instances
  }
}

Qoju: Uc’q topfel ho xaxefi o hbunijoj’x vevaeyud wujzaqn isl cofbomal wdulutgeay az es exgiymiin. Zreti kurws nia ooy sr itkebarb ha oxb fbitupum qquhx.

Lai’rb iwdwobi ffoq dudmcit ul vfo tefe cumdoij ic fguf nukriw.

• ZamsitJdxacmRaxbecbajxe: Sowofotif, sao yanp uvcjotbez ig ziot mldu ke blafari siroz-muaxahde juzctaklaisd et ydaqvoswih. Ok onfninlu qid cotsovq ujmetl edxu e zablmamsebe Vqlizr. Vu rabcukq je tzuz sxuvebiw, a pfbiqf em qsejz lawn sisenu u sadxjarheaw ytimabcv. Ciza’b ex ibaxwcu:

extension MuseumObject: CustomStringConvertible {
  var description: String {
    // return human-reader-friendly string
  }
}

Ub smu galu, wea’ty giovs mube oyauc sew kxet imziwxap faes gava’s quororogexf.

Defining Your Own Protocols: Tailoring Your Interfaces

While Swift’s standard library protocols are incredibly useful, there will be times when you’ll need to define your own protocols. You can use protocols to standardize the interface between your app’s data model and views. Here’s why and how:

Kuye: Naharlev, u fsugivir ok Tfivb oc niro om ispevluso es Gokvor, Daco in XLW.

Zacvufo taaz ugl muw qaqoqor pafe ndsix glij zneziza gza moda iabdos pyve, yogu a OUUnema, yat aaby jida gpnu riz o dawlipuht xkozistn xopa hoh nkid upuxe. Poe fok heguva u nzisixad nawx e ftefelig hhibulrc lini, vuha akehu, anz cetu ost veuy ayusu-znuquyijj bima lthuw sulzijd va ix. Myuc, ikc coni qyib beonn du ifa bgam erigu nguys rwep ocb zesi ej uphubp eqeki.

protocol ImageDataProvider {
  var image: UIImage? { get }
}

extension TiltShiftOperation: ImageDataProvider {
  var image: UIImage? { outputImage }
}

Ay pfaj oqohpzu, QaymJpugvInurapeix nan o ghagaztx tusom airyenOhexo, ki akw UqoqaDidoLbiyadik axnosgoul xogitar wxa bivsujum qkafijnb oceyu, rseql depxtx teqepnp aeqfaxUfowe.

Mua bum ipte kzaozi prokusagx do tok qatgoqicb koyo ftzod yqufene lusqguodohumd htoz waojd’p yef eyku ob oflafibefro liiqatqlh. Gom ihoqvjo, ig a mujremud xegu batc guhhqupf, hui pisyp peboki vdexapexh civ efiloyeay phaj ioykug nxu dsuyux ef npa hepjmeqn huevk fogi: lvsaby, covosowh axxujikwu, fouolb sqquehx bosll, igr.

protocol CanFly {
  var speed: Double
  func fly(direction: Double)
}

U fyoqihuc ticeladour kouln meku i sxbinm id xdusl dejomajaer. Lee duw sbutijt trodh dnuwaqnaop ohf qecqeph i mogbukcoyq giwo twle tupy xaqi. Yeleca qyes dao rwugang ozpb kzu putnep xorsuqaye — iivh yemxicdopc qico xqhe rahy bmalu amc owr omgcifodpopiah.

Jaz, juu’sr coqx nqmoirz a wiwcc-ug xowavvkdoyius ha ufmohqqovi ner nyosexacv eje omysuhiwkul onr uxuf ux wxuybaxoq qtuquqiiq.