Swift, why I won’t go back to Objective-C

By Robert van Loghem

Since Apple introduced Swift at WWDC ’14, I’ve been using the new language steadily in my new projects and existing projects. At first it was a love and mostly hate relationship. Slow compiler, slow Arrays, cryptic error messages, Signal 11 galore... it was the worst. When version 1.2 came out, most of my hate of the immature language and tools vanished and finally the benefits compared to Objective-C became very clear to me.

Robert van Loghem has been programming since he was 13 years old in Turbo Pascal, after doing over a decade of backend development in Java, and some Scala, he started developing Objective-C iOS apps in 2010 for NS and a little bit of ProRail. Now in 2015 he’s doing 100% Swift at Suitsupply.

Transcript

1. 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
2. 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
3. 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
4. M Y T O O L S • PaintCode • AppCode* • Crashlytics • parse.com • Cocoapods • Cocoacontrols • Dash • Sketch
5. 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
6. < 1 . 2 ~ > 1 . 2
7. “I started with Swift < 1.0 because I did some Scala in the past and it seemed to be the new Apple future”
8. 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
9. 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
11. 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
13. “Then Apple started on improving Swift and tuning its syntax”
14. “In december 2014 ~20% of the code in the NS Reisplanner Xtra consisted of Swift code”
15. 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
17. 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…
18. “Swift 1.2 launched and IMHO can be used in production”
19. “Now in since march 2015 I’ve gone 100% Swift”
20. 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
22. “So what was the most profound improvement since moving to Swift?”
23. “In the TestFlight Beta all my crashes are occurring in other frameworks”
24. 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…
25. S O W H AT ’ S N E X T ? • FutureKit • NotificationObserverKit • Reactive Cocoa 3.0

28. “My goal is to: make everything type safe…and be crystal clear about my intentions”
29. 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