S W I F T, W H Y I W O N ’ T G O B A C K T O O B J E C T I V E - C R O B E R T VA N L O G H E M - S W I F T G U Y @ S U I T S U P P LY T: @ S O U N D B I T E S E : R VA N L O G H E M @ S U I T S U P P LY. C O M 

A B O U T M E • Lots of backend in Java (’99) and some Scala • Actionscript/Javascript • Doing iOS since 2010 for NS, ProRail some small clients and now Suitsupply • Love road-cycling 100+km’s and tinkering with Bluetooth LE heart rate, power, cadence, speed, external displays 

M Y R U L E S • Let the compiler catch my mistakes • Concise • Immutability • It’s ok to be a little verbose • Good code does not need documentation • Refactor, refactor, refactor, … • Composition • Clear responsibilities • Embrace change 

M Y T O O L S • PaintCode • AppCode* • Crashlytics • parse.com • Cocoapods • Cocoacontrols • Dash • Sketch 

A B O U T S U I T S U P P LY • Doing instore sales apps on iPod Touches • Working on customer apps • Working on secret projects • need good people…who can’t go back to 
 Objective-C 

< 1 . 2 ~ > 1 . 2 

“I started with Swift < 1.0 because I did some Scala in the past and it seemed to be the new Apple future” 

M A R M O T T E C R E A T E A C Y C L I N G A P P, T H A T U S E S S W I F T A N D B L U E T O O T H L E C O N N E C T I V I T Y 11:11 01:43 41 65 31.2 39.3 3 164 89 

L O V E • let vs var • Options: SomeClass?, .None, .Some(x) • if let x = y as? SomeClass • No more headers! • switch, case, where • Type inference • map, filter, reduce chaining • closures where you can remember the syntax • Less verbose • Named tuples • Generics 

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H AT E • Weird compiler error messages • Slow compilation • Crashes… • if let { if let { if let }} nesting hell • Slow arrays and dictionaries • Symbolicated Swift crash logs 

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“Then Apple started on improving Swift and tuning its syntax” 

“In december 2014 ~20% of the code in the NS Reisplanner Xtra consisted of Swift code” 

B E T W E E N < 1 . 0 A N D 1 . 2 • Cumbersome but helpful syntax upgrades • private/public/internal access for properties • But after creating more Swift files the compiler slowed to a crawl… • Fail-able initialisers 

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B U T W H AT A B O U T M Y T O O L S ? • AppCode is WAAAAY behind, so proper refactoring is a pain… • PaintCode catched up pretty quickly • So did Dash… 

“Swift 1.2 launched and IMHO can be used in production” 

“Now in since march 2015 I’ve gone 100% Swift” 

M O R E L O V E • The compiler became fast (incremental) • if let a = b, c = d where a == • Nullability safety • Set • Default values 

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“So what was the most profound improvement since moving to Swift?” 

“In the TestFlight Beta all my crashes are occurring in other frameworks” 

R U L E S I A P P LY T O S W I F T D E V E L O P M E N T • Never ever use ! with optionals unless you REALLY know what you are doing it’s the main source of my crashes • Use if let all over the place • Use generics and embrace type inference and Swift’s type system in general • Let the compiler really help you… 

S O W H AT ’ S N E X T ? • FutureKit • NotificationObserverKit • Reactive Cocoa 3.0
 

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“My goal is to: make everything type safe…and be crystal clear about my intentions” 

S W I F T , W H Y I W O N ’ T G O B A C K T O O B J E C T I V E - C T: @ S O U N D B I T E S E : R VA N L O G H E M @ S U I T S U P P LY. C O M