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
   

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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
   

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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
   

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

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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
   

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6. < 1 . 2
   ~ > 1 . 2
   

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

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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
   

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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
   

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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
    

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

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

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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
    

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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…
    

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

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

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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
    

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

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

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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…
    

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

    

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27. View Slide

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

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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
    

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