Production Swift

In this talk, I use my recent real-world experience with Swift as a case study in an evaluation of Swift's production readiness. Take advantage of the lessons we learned to make the best decisions about Swift in your project.

Video is up here: http://www.thedotpost.com/2015/02/ash-furrow-swift-in-production

Transcript

1. Production Swift
   Ash Furrow
   

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3. Objective-C
   
   

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4. Agenda
   1. Swift is Awesome
   2. Tools are Immature
   3. Be Informed
   

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5. Swift is
   Different
   

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6. How is it different?
   • Static vs. Dynamic
   • Prefers immutability
   • Encourages functional programming
   • Safe (well, safer)
   • Experimentation via Playgrounds
   

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7. Optional Protocol Methods
   @protocol MyProtocol
   @required
   - (void)doSomethingNecessary;
   @optional
   - (void)doSomethingOptional;
   @end
   

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8. Optional Protocol Methods
   protocol MyProtocol {
   func doSomethingNecessary()
   optional func doSomethingOptional()
   }
   // Compiler Error!
   

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9. Optional Protocol Methods
   func doSomethingNecessary()
   optional func doSomethingOptional()
   }
   @objc protocol MyProtocol {
   

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10. Objective-C Interoperability
    • Interoperability comes at the cost of Swift’s purity
    • We loose a lot of safety
    • Don’t just add @objc because it’ll make code compile
    

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11. Swift is
    Better
    

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12. Objective-C Hurts Me
    if (indexPath.section == 0) {
    if (indexPath.row == 0) {
    } else if (indexPath.row == 1) {
    

    } else if ...
    } else if (indexPath.section == 1) {
    if (indexPath.row == 0) {
    } else if (indexPath.row == 1) {
    

    } else if ...
    } else if ...
    

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13. Pattern Matching
    switch (indexPath.section, indexPath.row) {
    case (0, 0):
    case (0, 1):
    case (1, 0):
    case (1, 1):
    default:
    // nop
    }
    

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14. Pattern Matching
    case (let section, 0) where section % 2 == 0:
    case (0, let row):
    case let (0, row) where validate(row):
    

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15. Self-Evaluating Lazy Closures
    class MySweetViewController: UIViewController {
    lazy var button: UIButton = {
    let button = UIButton.buttonWithType(.System)
    // configure button
    return button
    }()
    }
    

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16. And many more …
    enums
    closures
    tuples
    generics
    compile-time awesomeness saved a kitten from a fire
    went to highschool prom with me
    function currying
    functions are closures
    array.sort(<) better terroir
    immutability by default
    type inference
    discovered penicillin
    operator overloading
    clear mutability syntax
    native collections REPL
    multiple return types
    concise
    pattern-matching
    

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17. Tools are
    Immature
    

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18. Apple Tools
    • Xcode, clang, Playgrounds, SourceKit, code signing, frameworks …
    • All are unstable
    • Causes frustrations
    • Causes delays
    • Causes hair loss
    

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19. github.com/artsy/eidolon
    

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20. Open Source
    by
    Default
    

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21. Using Swift
    doubled
    our development time
    

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22. “We don’t expect to make our deadline.”
    

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23. Eidolon Problems
    • Enterprise code signing issues with Xcode 6.1
    • Compiler segfaults with optimizations enabled
    • Constant Xcode/SourceKit crashes
    • Unit testing problems
    

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25. Burnout
    

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26. We made our deadline
    

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27. Eidolon Awesomeness
    • We helped pioneer a new way of writing iOS software
    • Created many new libraries, tools, and resources
    • Used others’ new tools and contributed bug reports and fixes
    • Learnt a tonne, shared with others
    

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28. Apple Tools
    • Someday soon, these will be ready for everyday use
    • But not today
    • You will have unanticipated problems
    • There will be no known solutions or workarounds
    • Until then, use with caution
    

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29. 3rd Party Tools
    • CocoaPods 0.36 has support for Swift
    • Tremendous amount of open source effort
    • Pre-1.0, use with caution
    • Carthage is new but promising
    • Pre-1.0, use with caution
    

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30. Be
    Informed
    

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31. Making a Choice
    • What’s your aversion to risks?
    • How hard is your deadline?
    • Why are you building something?
    • How open is your team to learning a new language?
    

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32. Why Bother?
    

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33. Swifxpert
    Become
    a
    

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34. Blog
    

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35. Risks
    Rewards
    vs.
    

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36. Be Aware
    • Don’t be afraid to revisit your decision
    • It’s OK to switch back to Objective-C
    

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37. Recap
    Swift is Awesome
    Tools are Immature
    Be Informed
    
    
    
    

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38. Make an informed choice.
    So start now.
    You need to know Swift to be informed.
    

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