Being a software development providers ourselves, we noticed that some of Redwerk customers wonder about key differences between Objective-C and Swift. Understanding the importance of choosing the best technology to develop your project with, we created these easy-to-understand slides about before-mentioned technologies. Also, you can find more information here: https://redwerk.com/blog/10-differences-objective-c-swift

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10differencesbetween
Swi &Objecve-C
PRESENTATION

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ThemaindifferencesbetweenSwi andObjecve-C
1.Op onals
2.ControlFlow
3.TypeInference
4.Tuples
5.StringManipulaon
6.GuardandDefer
7.7.FunconalProgrammingPa erns
8.Enumeraons
9.Funcons
10.DoStatement

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1.Op onals
Op onalsallowfunconswhichmaynotalwaysbeabletoreturnameaningfulvaluetoreturn
eitheravalueencapsulatedinanop onalornil.

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1.Op onals
InCandObjecve-C,wecanreturnnilfromafunconthatwouldnormallyreturnanobject.
Wecan’tdoitforfunconswhichareexpectedtoreturnabasictypesuchasint,float,
ordouble.

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1.Op onals
WithSwi,youdon’thaveworryaboutthis:
Thecompileritselfwillraiseanerror,sincexisanop onalandcouldpoten allybenil.

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1.Op onals
Beforeusinganop onalvalue,youneedtounwrapitlikeso:
Alternately,wecanuseop onalbinding:

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2.ControlFlow
InSwi,thecurlybraces({})arenotjustagoodidea,likeinCoraC-likelanguage,they’rethelaw!
UnlikeObjecve-C,Swi treatscurlybracesasmandatoryforif,for,while,andrepeat
statements.

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3.TypeInference
InSwi,onceavariableisdeclaredwithaparculartype,itstypeisstacandcannotbechanged.
Thecompilerisalsosmartenoughtofigureout(orinfer)whattypeyourvariablesshouldbebased
onthevaluesyouassignthem.

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3.TypeInference
Thecompilerwillraiseanerrorifyoutrytoassignanumericvalue,suchas10,toourstr2variable.

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3.TypeInference
InObjecve-C,youmustalwaysstateavariable’stypeexplicitly.

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4.Tuples
Swi supportstuples,valueswhichstoregroupsofothervalues,thatdon’thavetoallbethesame
type.Forexample,youcanhaveatupleofStringsandInts:

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4.Tuples
Themostobvioususefortuplesisreturningmulplevaluesfromafuncon.

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4.Tuples
InObjecve-C,wecanuseblocksinsimilarfashion,butit’snotasstraigh orwardorelegant.

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5.StringManipula on
Swi offershugeimprovementsoverObjecve-Cintermsofstringmanipulaon.
Declareyourstringwithvarifyouwanttochangeitinthefuture,orwithletifyouneeditto
remainconstant.

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5.StringManipula on
InObjecve-C,concatenangtwoimmutablestringsrequiresyoutocreateanen relynew
NSStringobject.

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5.StringManipula on
Stringforma nginObjecve-Cinvolvesinserngspecialplaceholdersforeachdifferentdatatype
wewanttointerpolateintoourstring.

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5.StringManipula on
InSwi,wecaninsteadinterpolatevaluesbyinserngthevariablenamesdirectlyintoourstring.

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6.GuardandDefer
Everheardofthe“pyramidof
doom”?Ifnot,here’sasnippetof
Objecve-Ccodethatshouldjog
yourmemory:

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6.GuardandDefer
Fortunately,inSwi,wehaveguard,
anewcondionalstatementwhich
canmakethiscodemuchmore
readable.Guardstopsprogramflow
ifacondionisnotmet:

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6.GuardandDefer
Swi alsogivesusthedefer
keyword,whichprovidesasafeand
easywaytohandlecodewhichwe
wantexecutedonlywhenthe
programleavesthecurrentscope:

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6.GuardandDefer
Asyoucansee,weneedtowrite
fourseparatecallsto
destData.dealloc(dataSize)tomake
sureourpointergetsdeallocated
evenifguardmakesthefunconexit
intheeventofanerror.

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6.GuardandDefer
Withdefer,wehaveahassle-free
waytocleanupbothourpointerand
ourcode:

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7.FunconalProgrammingPa erns
Swi incorporatesanumberoffunconalprogrammingfeatures,suchasmapandfilter,which
canbeusedonanycolleconwhichimplementstheColleconTypeprotocol:

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7.FunconalProgrammingPa erns
Objecve-Chasnobuilt-insupportforfunconalprogramming.
Tousethesesamekindsoffuncons,youwouldhavetouseathird-partylibrary.

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8.Enumera ons
InSwi,enumeraonsaremorepowerfulthantheyeverwereinObjecve-C:theycannow
containmethodsandbepassedbyvalue.IllustraonofenumsworkinSwi:

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8.Enumera ons
Enumscanalsoberecursive,sowecanbuildalinkedlistusingtheindirectstatement,whichtells
thecompilertoaddthenecessarylayerofindirecon:

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9.Funcons
EveryfunconinSwi hasatype,
whichconsistsofthefuncon’s
parametertypesandreturntype.This
meansyoucanassignfunconsto
variablesorpassthemasparameters
tootherfuncons:

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9.Funcons
Swi alsoallowsyoutodefinedefaultvaluesforfunconparameters:

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10.Dostatement
ThedostatementinSwi allowsyoutointroduceanewscope:

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10.Dostatement
Dostatementscanalsocontainoneormorecatchclauses:

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Conclusion
Eventually,wecandisnguishsuchadvantagesofSwi:
protocol-orientedprogramming;
protocolscanbeimplementedbynotonlyclasses,butalsoenumsandstructsaswell;
protocolsprovideanelegantandconfusion-freealternavetomulpleinheritance,asasingle
objectcanimplementmulpleprotocols;
light,flexiblesyntaxandnumerousfeaturestoguardagainstcommoncodingerrors.