What's up with Swift 5?

This talk was presented at FrenchKit 2017.

Transcript

1. WHAT'S UP WITH
   SWIFT 5?
   BAS BROEK
   1 — @basthomas
   

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2. IOS @ XING
   MOYA
   SWIFT WEEKLY BRIEF
   2 — @basthomas
   

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3. ABI STABILITY
   3 — @basthomas
   

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4. !
   4 — @basthomas
   

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5. ... STOP ME IF YOU THINK
   YOU'VE HEARD THIS ONE
   BEFORE
   5 — @basthomas
   

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6. SWIFT 5'S
   PRIMARY FOCUS
   IS ABI STABILITY
   6 — @basthomas
   

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7. This would remove the need for
   apps to distribute their own copy
   [of the Swift libraries].
   7 — @basthomas
   

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8. !
   8 — @basthomas
   

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9. REQUIREMENTS
   > Generics features in the standard library
   > API resilience
   > Memory ownership model
   9 — @basthomas
   

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10. REQUIREMENTS
    > Generics features in the standard library
    > API resilience
    > Memory ownership model
    10 — @basthomas
    

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11. GENERICS FEATURES IN THE STANDARD
    LIBRARY
    > SE-0143: Conditional conformances
    > SE-0157: Recursive constraints on associated types
    11 — @basthomas
    

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12. CONDITIONAL CONFORMANCES
    // Swift 4
    extension Array: Equatable where Element: Equatable {
    // ERROR: Extension of type 'Array' with constraints
    // cannot have an inheritance clause
    }
    // Swift 5
    extension Array: Equatable where Element: Equatable {
    var hashValue: Int {
    ...
    }
    }
    12 — @basthomas
    

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13. RECURSIVE CONSTRAINTS ON ASSOCIATED
    TYPES
    // Will not compile in Swift 4, will in Swift 5
    protocol Sequence {
    associatedtype SubSequence: Sequence
    where Iterator.Element == SubSequence.Iterator.Element, SubSequence.SubSequence == SubSequence
    // Returns a subsequence containing all but the first 'n' items
    // in the original sequence.
    func dropFirst(_ n: Int) -> Self.SubSequence
    // ...
    }
    13 — @basthomas
    

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14. REQUIREMENTS
    > Generics features in the standard library
    > API resilience
    > Memory ownership model
    14 — @basthomas
    

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15. MEMORY OWNERSHIP MODEL
    > Partly implemented in Swift 4 (SE-0176: Enforce
    Exclusive Access to Memory)
    > Swift 5 takes on "only" everything that is needed for ABI
    stability
    15 — @basthomas
    

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16. MEMORY OWNERSHIP MODEL
    > The Law of Exclusivity
    > The standard library must adopt ownership annotations
    on parameters
    16 — @basthomas
    

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17. SOURCE STABILITY
    > Source compatibility mode
    > Supports Swift 4, maybe Swift 3
    17 — @basthomas
    

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18. SOURCE STABILITY GUIDELINES
    The current implementation must:
    > actively cause problems for users
    > be clearly better and must not conflict with existing
    Swift syntax
    > have a reasonably automated migration path for
    existing code
    18 — @basthomas
    

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19. SWIFT EVOLUTION
    19 — @basthomas
    

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20. PROPOSALS
    > String ergonomics
    > Improvements to existing standard library facilities
    > Foundation improvements
    > Syntactic additions
    > Laying the groundwork for a new concurrency model
    > ... and more?
    20 — @basthomas
    

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21. EVOLUTION PROCESS
    > Proposals need a working implementation
    > ... including test cases
    21 — @basthomas
    

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22. !
    22 — @basthomas
    

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23. HOW DO I KEEP UP WITH ALL OF THIS?
    > Swift Weekly Brief
    > Swift Unwrapped
    23 — @basthomas
    

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24. THANKS!
    @BASTHOMAS
    24 — @basthomas
    

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25. REFERENCES
    Swift 5.0 goals
    SE-0143: Conditional conformances
    SE-0157: Support recursive constraints on associated types
    SE-0176: Enforce Exclusive Access to Memory
    ABI Stability Manifesto
    Ownership Manifesto
    String Manifesto
    Chris Lattner's Concurrency Manifesto
    Moya
    Swift Weekly Brief
    Swift Unwrapped
    25 — @basthomas
    

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