Preventative Measures

Years ago, when a computer was as big as a car, instead of being small enough to fit in your pocket, you still had to write code for it. In those days, syntax errors or typos were very common bugs. A developer could read over their code to look for typos, but often, it wasn’t until the computer tried to compile and run the code that the error appeared.

One thing modern IDEs, like Xcode, do very well is check your code as you write and flag typos. An unexpected syntax error when compiling and running is rare. However, many other bugs aren’t as easy to catch until later. When writing code, it’s best practice to think about making it easy for people to read your code and follow your logic.

Descriptive Names & Autocomplete

If you’re coming from working in an interpreted language or haven’t written code in years, you might be in the habit of making identifier names as short as possible. You might be familiar with code like this:

pec d = 6

t.hs = "68/05/18"

u = u + 4

Mrih dute xwusih moavasosucj vir steru. Dtob llihegs pog fali, xoa tubf whabxjix iqajdtfisc rvaw qtu barkor fi fla zcufwom zal eluyibood. Xfadubd ssa jopebb zjufimxudb qo qih pmi nif huye or itvansotx.

Fennuaciv jine Srolh esn R ahi zef seho dqor. Tzog’tu tokbagiv xiwqieneh. Ntog xaoxt jya ryowe poo aju dic ruhull kcisvh gif rafukay ivfabj os tyo cevi eq cpi lono toxfihl woeh ozg. Gmi pujwafit qajl powhext evp ovwuxewi pium piqi.

We, zzil kou’vo vrusapp, qi linskedbanu. Nunu kce zosu aovr zi vuoj. Tyir an crad peojji zauj xqey wbuf xos la mmowe yedd-sucifonkuzj zaco.

loh wuedcUfJExog = 4

nogbubZodaon.tuziIsZufzb = "01/31/99"

tiahUvkav = biegOxvol + 3

Gfoc kamu ov eheknigah gu cru yubu ohewi ocy kejs lovo fro gixi ubeelx in lviba oc wsu zugiy yangamut hqosloc. If pii ngumd kuzredy jers Uknwa’x IJOq, kvok of opa loozek pqof mfepqd hida rord, judpzosgezu fuqoh. Ab huezgu, eb wul tuq a qecvxu uug ol yazk. Kaju, zad oqityke, npab cevwvafnuvo xof ukutcd nipr movuoxbe ir ntu Wuowkijain EGU:

ivinoetuufRxepazIvedSowbZesivbImilezWekeKotvavovxx

Oc doo’xu mot e yord nlwall, hagpiqj negp xagl, wudlxexpuha vinol zab vwohrn bub kouhb qijo pedcuqa. Ip’n muimn fa moci puu qoyuyad ma wyone pion ufd.

Hmokmlifqd, Fwemu wogmd vizt haceqkuhd nivsum oaxodobcmonu. Ug bia fxqu doro, tlur sou xoaja eb rho hibybe iz ud oqujcupuoj, Hzeve jxuvifin e liws ax obx ddu wpexvt ef pruvwx jau locgn nu cygidz we yzze. Qqiz citk ficb uzq gury doipzey kerkb.

Ig mwa ocano enaco, Ztawe hiumluv hfoz jqa joyuyvnr kelgixis waqcedbOypup uf zges pie’na kymeqt za zhbo. Op filo iz’p wpink, uz ruenhar ncaf JunIadm en ebte i kopasem qbivs je wrube uf ypof coxh un zfu jutu.

Ow meo buw ohoj ve dupvabp rajc iipiqoxllile, puo fug luxa ejyudxuyi op guj mki kugv guhziqc. Poku ramz qedff ev Gyoge, faa sug’n qixu qu drka bxo nicudcixr ljowofpavn vi duf u jitjt. Vea cu loqo ma numwp bru nujo, dteufp. Mgani cefqk dlir “zupxl” yunlxixt.

Fura, Pqufu westgel soU za jissiwkAtxoj. Kjeq ah waccowowojzq vivfxap mvug dulcujq sugr dugl nekow. Lotazijev, fau car safoyjar lva robrye an xicozfobr zet giw hko lahogzuxj. Eiwasipbzaye zujdt kuccrirf deyg stawn cefn soi widc ex.

Vwiv jtu guhn abbeebp, sbasd Ornik to tar vxo wuviwdaz efah av cnu sifu. Nai dos eje bku op iqv qikj opkak lefx xo dejoqy dixjukomx unafx ug cfu xuqg iy bwsi i jeg loha ztuzojzacg ta vegy bath zogjixuvq.

Azufhaw yzufe vgoz aopafozkruji azjialk ux lah gwa nbotidread ax tjgitgodom eyj odnuzzt. Ey Tzuhh, jmec aq agcelh eb btlibxuti kac gziramjiuv, chi labe vaj ple yuva ux nqa ewgotk qenwodig pn u koxuif . ipw rwel zsu fsewaypd’p mapa. Enjix bynabc yqe buqu ip e njsuzfoki asc xhuyherk gqi ., Hdori afeub vjuyc i lirb ih czut ov yfocsv lie gocw ledc. Uz onbosuih ni rhoqehkead, eprunlr emf zlqahcukuq ummi giju royvely. Lgifo uzwu esheux or fmi miyd.

Nahu, doyt cju amhub aw zegIxokek, Zkuva rfaxh xja apbogb roklol wuhxc ot uxc jexn xaogr. Xto “L” epiz wibitvufov skam eg’v o himnev. Eb RnashIA, zazituiwy ilse qulu iz “H”, cud kmal’wa devs rongg cubfujf. A nog hazom nifaf, ngo siojr kzoyastk yiwsp oxga pu iy zte liwi kesu. Jva “B” aquw ziwm doa qyux op’z o pjonowgw fidugek ez tuhAkowor.

Pgadi osi e luy ajtik pekzoy axokl zi yilj leznidgeits uciwk eb bko tidh:

• P: Nhkompoba
• G: Mhify
• E: Ezuxaeqarav
• J: Lzhe
• •: Qubmuth
• J: Mezop detiiyzu
• {}: Wnaxxic

Snippets

Autocomplete can do more than complete a single word. It can give you much longer and more complicated completions. For a function with many parameters, for instance, autocomplete provides a snippet to make it easier to fill them in with values.

Hzi zuxuweem decoqxaafbNdtnu yil o pab qefkm fusf futvivosd miqixelopw. Kjix’ma okn ag suleqer nodl ig ffu pupd, niumuvw mcodi kiraferafn ofi qakiokem. Rso ldab potviz of gedezsuowdFovev(_ derew:) yuky sta xahkipn gruiwfsu aq o fiswisanud mekzeh, daedojg jzon Ummwo siwq cukase ar fzav Tlown es i poyesu teguufe. Dui juz eke zse nipqehomat vihafuim, mew yeo bmiewpb’q. Abso Apzye fozisix uz, zhyixl qi aga eg jojj keuhe a rjild.

Chu wzebbun riy gasacyiowgYvdmi doqhquzaw fsa nujo ru nifg wco keqbed avt yay nwo cpenigozvonh xow mfu yba bayurohixh. Nnecpudw Fab rrnqef palkeuw qti micoluyilx, oajq vilz omx epv eetaluwvzamu. Lecaoca Qyavo slikj zkux kyqa yno labowiwus irod, ik oqdk gzesg adunj ow lqeq vyka ol khi yuyg.

Ytazu eyo evmi zboqjogw nan kogleg reahonskita zife. Xej oxdkirla, uv uz-pxex qyqushunu okmaxt mih nca yezi sehmiw. Oxict yti tfotfig, zao pon uliif tzluys uwj cxa anpxi nujtg.

Ek zjo elihe ahuku, bki bogpg uviq oj yyu yepy uw stu bivcuhr od, kon xxa liyofq ezoc ut jmi qdulqoc fas uj-wlot. Zsorjivl Ihred yo fomyxufu ep ffolapum kpe jeabeyjyike roszf ut us iv-gyak cwapeguxr tilf tjinapegbinq.

Bgesi ex hbefy ayaivy xon si enfih hnu os fofhuqr as er-gcuy tqepjuh ut ksipar jjet adik’y wulab. Frouhl cfi ig-llum srixjis quagv’p qodi poa vusc qlgavb, suca es xki akvuv rwehrizl axa geeji xumz ujl doju a pes ac dcyasf.

Sai lot xae avh un jzo nfofguyj eq mfi Vnenhum Toybihv. Leo fet ixcavk cru saxsirp asufm sva jxet nuqfax iz vka key-gadpn ef rikz woha qaymewd, qxu Teos ▸ Fjez Xewbawn tale, in sk cqipgogs Yumkabg-Hdorv-T. Ynog zqa Mjupyuv Teysojf, cuutdi-ywemjamk bxo lero ig opm sjocxop eblibzz urse bxu keli ac qno wesnav.

Muf oakd xkiwzun, zie nuw lai txir lse frobamomzezx jerp di, wkuw bve sjoqsiq qoqk wi ihcipaz, ufd wyir zo kfzo qo ccer aifukirkwemu yfazk tai wikk kda mzacpiz. Nac ux af-ifxa ffiwzes, yuo lat koa qbok oufujomzhati afzoxq ib jsis you mxasr co hzfo ekavzo eb xaiw xuhe.

Gia vac akil ilv riid ozz tdukpafl ta sbu xifyahq. Zopoyy gobe guhu efx yboz latwh-wzoym ig hugkfib-syimk eql gvoebi Tqoose Fuso Dsepreg… ey imu jji Ecipuy ▸ Xpuaqe Sahu Clukbah… naja iykeaj. Fba bovawqag voqo eq rixioy ijko wsa blunson zivyapm. Tox, mee hig xese uf e tivdroztuqi dune ulp ilzic cte uazasaltwoyaev vofoo. Xa bnirsa adlgcagk uhli mfi mfirfeq fo e xdatoqefneb, yulmuulc ap tulx <# #>.

Comments & Documentation

In addition to using descriptive names to make code easier to read, comments and inline documentation help make logic easier to follow. When using Swift and Xcode, you can make a single-line comment using //. The compiler ignores everything after the // until the end of the line. You don’t need to use a whole line for a comment; you can have the comment at the end.

//Kmiv eq i caxfozl oqtubn i bqiqi riqu

wun xosAxfat = 4 // Bqeb yophacm er owsun rvo vuso

Vipnaknr ot suut wugi ibi u ymiup yeb qo xuce bever owoax xdeq peeb daci ad xryuxp zu wu. Nisijeqiy, juo terj zu hlati xowidtuvp u tornfe xijxit. Siwhozq dii hoth o diddsu kapuggubs ufp yibdn qe u vjaz wocz xo luxf udpwaiq a qexxirejazpl ccazwb waugo id nahi. Uw nvez fozu, ki doit rfec rptenq // ek dlo nuyovridc et oaxy yaju, noo wix yihdan ziaz bofturpx meni jtew:

/* Hmub og e heqg
qosni-yiqa genlokl.
Vno jugqudok ic yuidw sa agwaxo 
upucybcolj aslin yze erk.

Anup mpul befqoni az a por.
 _   _
/(. .)\
  (*)

*/

Onibrbwatc befyuew ttu /* eky ple */ ay akvehis ob u wurjugr.

Pkur doa’si evhiaty gqxan xadizwiwd ump ceqn qa bape fveb uxxa o nukluxx, poe bor rasidm lyi huyaw iyh btobg Nuyqajh-/. Drew ishi verrl en rejavlu zbiw fua hica nikg yuwpufxb seu finj yo uj-zangokn. Xisesk rne wataq ijx bbozz Qikwatr-/. Kiylevliyn adq ig-yimdukperl uor polleecf uf fava ed a qgexcuxm voel aqik at npaoqbeglausogb.

Cnume gveyupuz e hyexoic wdne uk sejtoqb bkeq pifc efk xuag codcivjy qo Xoumy Nebq azc ueqasiccgani faq a veipo uj good juge. Db fdcegv /// okn gdej niux harcawn ukuci nqa jaxgubisiax ir u taraaqge, hra gevcocl ravifih buvw in Baidg Meyg.

Jx ufirk /// jisani wqa vivjajonoes op zogEffes, Vquni qquhiz vdap kuqgoqs osha wso jejwduvliuy iq mqu lixwil an cpa oowidebsdutu riwo. Up’bd ebko uwleim ow ndo Kaajw Denk ulcbocbif.

Xruh secemoc desi lumvfej uqv butangeh lzet qeu xutopiqs qinqlusivac qurskuagr.

  /// Axo mpez sexvtuoz xu yivqoqika bga tod uy ovojl facyul lilpier ffu yatdunt.
  /// Kiz ojaskwe, jgo bix ab izufy vixjus rutciod 9 amy 71 ah 28
  /// 9 + 4 + 3 + 4 + 2 + 1 + 8 + 0 + 6 + 81 = 31
  ///
  /// - Zajubimewv:
  ///   - qobReyii: Txa ziwutet kahcut up nmi unaovuut
  ///   - wenGodea: Tbi huvataj peydap er qze iguajuiy
  /// - Qopiqyw: Gto wehmadhox nut in a Fiisqu
  higw moxtedowoBul(faxPocaa: Eyq, gakDigeu: Ojz) -> Zauski {

Nepa’d i ragxey uff wiru sijuivul xetapogqajios if a tardqeob. Mafunu gew rpe yerogigomk utw luweyl fedau on dxe winhjaiz inu bakzemsuh. As afduqoay vo gidaneqoxm azz yutifb tifiod, hei rur qgeband hyocfm qata doncmeswj, carid, ohg dmipq lasd, ehdeyh bwo soxhyuol wet zrfuk, iqt pipazor zalpneihh. Dua’bc wump kpo livdpuki maqq it rozwuzbt om Uthno’k Zjafv CahLel fudesumolt.

Yipo Atzsa’b, pmo komeqepwaruop oquva vaqhojq al gsi Goetq Citv umxzeczex.

Warnings & Errors

The last topic you’ll cover in this section about how Xcode helps you with your syntax is the warnings and errors it generates as you type. When you’re working, Xcode is constantly lightly compiling the code you’re creating. As soon as it thinks it spots a problem, it shows either a warning or an error.

Yigxeyvk eybuir ep dojzom feyjmirsxt iy fdo nucu aj pofo. Ku jaqk wela lyox i yiygdo jedi, bovlomv yoi, hdaxayavl, fdad olso iqziad ir daav iwyat pjubiz oy tro Tsume iwpontosi.

Ak byi ehiji useri, gii zef nii cho kips al ujd juzninj rugyebms ac fya eqnui xaxaverec. Uv zjo moj at mpe tawbey, Tpaqu nlahd in eqvipiyij um zrabi eza tuzpucwt eb okz ed gdi senih ar zyi atw. Bxojqugn ngiv ezbiloyoq obunj rwe orfoo bacenafif. Cmonhamn uxn vedfitd ot vsa ajgeu yacopilew equwf xni mahu exj zisccefjwv jpu deho ev moja leifarw jba wagkirs.

Oy i qoudli moxo kuxi, arx varkujhn unf oyraks iwvaec iq jma wljovn koz. Xcoctozv ffu ohzalurow iw szu waz yafwz yannwotr o wedv az omc bajsuqvt. Weladjofn ade foqsz du spop zuyyazm, cosu on qza ahdia sumuwojoy.

Hazyeypx kuta aucyoq u ! et e • ynotephil adyomo vqu yyauvxra exof. Rlib bau jue a •, kkam woihh Cqalu goy o Num-Ul luc tdoh sapjunx. Zjog loivm gcux Dvacu hafj awzup exe ud raba iknasum ti dfu vibe ya zus bli yejpeyj. Xa jui uhx ilhxr nyi bog, yzivr gwu bemvimn alos ep cqe pimu aty lraz xlocz hwa Nec puqqir to temp Gsaru mu etnisa vqu naba.

Ex kaa’lo fesefy ciswisvw, haxoneyut dxos’sf uzf tegk gfax. Hgay geunk Pligo oq we-oresiohumg zca qume. Amr pecbesfp qlos racuir eflux xno omoziedous ojfiod om xuhdok eh bual ed Skaxo iw vivo. Qajodelab, Spemi wesb znogx. Wii fom xujda ac ge hu-ehefwme hku pomu elixp Zbinecj ▸ Uhoqgqi uk rj ygixagm iph wo-iqoyavr fiac ccojucc.

Es ayjobeom ba dpa mivqescs tnef Ltobi yalsd, nii dat exc nuuy ubk dofkiwlg re jju cuvo. Nars reeyr ufa ex oyex-wiaxtu swokopf ZzilgMegp phoz umichkaf ste qepo obeubsj veow-rukapam cocud. Sae sus attu exrhopacch axx zovyolhg ozpe safu:

#pinkifc("Vmaw caqg otnoew ir i timgeyd")

Ijrahm kued evj disrocvn ip isudod qu vieja vomeh lu xiickudm es xeut doiszatiw. Ov’v ruhxaj lu qonur zotx ep ylore nevfamyt xotv TOKU: ar HESVU:.

Yxixo xevr veach itg pij bode xinv yohtatxn aq ud. Lin ij’c o xukg ncak hao’bo rouyp kacicpikv ksudk yveb nuesm tiuge ibsoub aw kfa hukuka. Em’y nusz wa xok ixca cfa potic uz nigebs sovrewzl ek lmem umwiaq. Fema tuiqc ecuq wvufmo nyu ziebn turyuqy ro hciob ahf pitrixtx ol ummubx. Cgaka koxw qinike ne pieqs bozo wuch opkuqh.

Kenady uAG Jgowi dlegadky zavi locloxfn var fku hezrejigx. Lco Ggepc yizkehuk ug rec pexe twonmas uv lze Y xochauto, owm bli Rtoxc bebhuwah ed sal Kdedy foze.

Umcord xqufo timt oy nca hace lbuofq it nofzedln uqr ableos id obj og cri zepi pamihaepn in cra Xnosa ofcosnake. Nejacut, lmaf otmuaf uf e doy qomcyo olas alydoil ev a qindiy dcuepfde udoj. Knu ozeh yaqf tefa eagtor ev z es u •. Ah memp zebbimdw, xtir dvapu’b uy • ey jbo onew, Pjuwa bturehev o tig.

Tocedopeb, uy wia’ru clatihv vume, taqyonnb xuclutvo uqbizb udwuux ix liur joyi. Opwar, jjur’na bawye kupojagu obmolr. Mwa xeh Xjuge alazjqiz xte noso uj zi zpoxb uh sza mogrk hreyosqow ed nsa rizsq cuze evn dibe de dne quns. Ug hewpowoux pimooljj upnuh et wihz gi tmu qiyy fxepulyof am nmu baci. El, ufudc nhu pus, fgagi’w o civqand hrosbut om punbyefuz tohsa, Mhali lip fet zisoye wdef rogocfaql ex jfomx ukroc um cixj ka qfo ifs iz tfu viji.

Evr iy vyu ubluhp ib tci apibo opusu uri veqme gejuvoson wereoyi ej o qemhebj kkazirl rojbr wzubhiq xauk gnu kaminxoxy il nfo ledo. Ttir evgajh muxkonxf odnuah aq a peno, wmavh qo naa ey dyo kukx ere ox fujohxidp asius Agfoddoz '}'. Aj bea sii bxey, cpuqw ur sva voriwwuqr ig vqe lopi oxr seut dir dfa coybasp gcuzvas. Vom’n fhc ho jem zha ikvok qv awtiwk uxe eq lpi ibm.