Types in Swift

Cocoa勉強会関西 #60の発表資料です

Transcript

1. ܕ
   
   @yashigani
   Cocoaษڧձؔ੢ #60
   

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2. yashigani
   id:yashigani_w @yashigani
   Mobile Application Engineer
   http://yashigani.hatenablog.com
   Hatena
   

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3. https://flic.kr/p/nBzE6V
   ܕʹϋϚͬͨ͜ͱ͸͋Γ·͔͢
   • ίϯύΠϧΤϥʔʹͳΔ΍ͭͰ͠ΐʁ
   • ܕ੍ͬͯ໿ͳ͚ͩͰͱʹ͔͘अຐ
   • id࠷ߴ΍Μʂʂʂܕͱ͔͍ΒΜʂʂʂ
   

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4. ܕͬͯԿʁ
   

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5. ܕ͸ৼΔ෣͍
   

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6. ৼΔ෣͍
   • ৼΔ෣͍ = σʔλߏ଄ + ॲཧ
   • Ͳ͏͍͏σʔλ͕Ͳ͏ಈ࡞͢Δ͔༧૝Ͱ͖Δ
   • ΠϯλʔϑΣʔε͕ݫ֨
   

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7. $
   

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8. ΞυϨε௕ͷϝλσʔλ
   • ϝϞϦۭؒʹ͓͚Δม਺ͷҐஔ
   • ௿ϨΠϠͷॲཧ͕Մೳͳނ
   • ϓϦϛςΟϒ͗͢Δ
   

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9. 0CKFDUJWF$
   

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10. ৼΔ෣͍ͷϝλσʔλ
    • isaϙΠϯλ
    • ม਺͕ৼΔ෣͏΂͖͜ͱΛࣔࠦ(ಈతσΟεύον)
    • ͨͩ͠ඞͣ͠΋ै͑Δͱ͸ݶΒͳ͍
    • ม਺ͷৼΔ෣͍Λଋറ͢Δ΋ͷͰ͸ແ͍
    

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11. 4XJGU
    

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12. ৼΔ෣͍Λ໿ଋ͢Δ΋ͷ
    • ৼΔ෣͍Λม਺ʹଋറ
    • ͋Δܕͷม਺͸ͦͷܕͷৼΔ෣͍͔͠͠ͳ͍
    • ܕͷ͋Δϓϩάϥϛϯά͕Մೳ
    

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13. ͳͥϓϩάϥϜʹ
    ܕ͕ඞཁͳͷ͔
    

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14. ܕ
    ܕ͕͋Δ͔ΒɺܕഁΓɻ
    ܕ͕ͳ͚Ε͹୯ͳΔʮܗແ͠ʯ
    ʕेീ୅໨தଜצࡾ࿠ Վ෣ب໾ऀ
    
    

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15. /4%JDUJPOBSZ
    

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16. NSDictionary *user = //...
    NSString *name = user[@"name"];
    

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17. NSDictionary *user = //...
    NSString *name;
    if ([user[@"name"] isKindOfClass:
    [NSString class]]) { //!!!!!
    name = user[@"name"];
    }
    else {
    //!!!!!
    }
    

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18. https://flic.kr/p/7BD2UE
    Too bad
    ߏ଄͕ෆ໌ͳͷͰσʔλͷଘࡏΛஅఆͰ͖ͳ͍
    Կ͕ೖ͍ͬͯΔͷ͔ෆ໌ͳͷͰσʔλܕΛࢦఆ
    ৼΔ෣͍͕ແ͍
    

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19. ܕ͕ແ͍
    

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20. .PEFM0CKFDU
    JO0CKFDUJWF$
    

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21. @interface User : NSObject
    @property (copy) NSString *name;
    @property NSUInteger age;
    @property (getter=isPremium) BOOL
    premium;
    @end
    

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22. User *user = //...
    UITableViewCell *cell =
    [tableView
    dequeueReusableCellWithIdentifier:@"
    cell"];
    cell.textLabel.text = user.name;
    

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23. User *user = //...
    UITableViewCell *cell =
    [tableView
    dequeueReusableCellWithIdentifier:@"
    cell"];
    if (user.name != nil) {
    cell.textLabel.text = user.name;
    }
    else {
    //!!!!!
    }
    

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24. https://flic.kr/p/i74K6M
    Too bad
    σʔλͷߏ଄ͱܕ͸දݱͰ͖ͨ
    ΠϯλʔϑΣʔε͕ෆఆ(nilͷՄೳੑ)
    ৼΔ෣͍͚͕ͩ͋Δ(ଋറ͕ແ͍)
    

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25. ܗແ͠
    

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26. .PEFM0CKFDU
    JO4XJGU
    

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27. struct User {
    let name: String
    let age: Int
    let isPremium: Bool
    }
    

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28. let user = //...
    let cell =
    tableView.dequeueReusableCellWithId
    entifier("cell")
    cell?.titleLabel.text = user.name
    

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29. https://flic.kr/p/egaNwP
    Relaxed
    ෆ֬ఆͳཁૉ͸ϏδωεϩδοΫʹӅṭ
    ΞϓϦέʔγϣϯ͸σʔλΛදࣔ͢Δ͚ͩ
    ৼΔ෣͍Λଋറ͢Δ͜ͱͰ໿ଋ͞Εͨڍಈ
    

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30. 5IJTJTܕ
    

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31. ܕͷ͋ΔϓϩάϥϜ
    • ৼΔ෣͍͕໌֬Ͱ׬શ
    • ͕ͨͬͯ͠ෆඞཁͳ৺഑͕͍Βͳ͍
    • ϏδωεϩδοΫͱΞϓϦέʔγϣϯͷ෼཭
    • ΠϯλʔϑΣʔεͷΈʹґଘ࣮ͨ͠૷
    

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32. 0OFNPSFUIJOH
    

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33. func parse(JSON: AnyObject?) ->
    (User?, NSError?)
    let JSON: AnyObject? = //...
    let (user, error) = parse(JSON)
    if let e = error {
    //...
    return
    }
    if let u = user {
    //...
    } else {
    // maybe user is nil...
    }
    

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34. https://flic.kr/p/DC3Q
    Too bad
    user΋error΋nilͷͱ͖͸Ͳ͏͍͏Τϥʔʁ
    ΋ͬͱ΋ͬͱstrictʹදݱ͍ͨ͠
    (User?, NSError?)͸ૉ๿͗͢Δ
    

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35. ܕΛഁΔ
    ܕʹΑΔܕͷந৅Խ
    
    

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36. 3FTVMU5
    

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37. enum Result {
    case Success(T)
    case Failure(NSError)
    init(_ value: T) {
    self = .Success(value)
    }
    init(_ error: NSError) {
    self = .Failure(error)
    }
    }
    

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38. ܕഁΓٕͦͷ
    ʙHFOFSJDTʙ
    

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39. enum Result {
    case Success(T)
    case Failure(NSError)
    init(_ value: T) {
    self = .Success(value)
    }
    init(_ error: NSError) {
    self = .Failure(error)
    }
    }
    generics
    

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40. ҦΘ͹ϫΠϧυΧʔυܕ
    • ͱΓ͋͑ͣ͸ͳΜͰ΋ೖΕΒΕΔܕ
    • ಉ͡ϥϕϧͷ΋ͷ͸ಉ͡ܕ
    • ΠϯλʔϑΣʔεΛܾΊͨͱ͖ʹܕ͕ܾ·Δ
    • func parse(_:AnyObject) -> Result
    • Any/AnyObjectͱҧͬͯղ͘ͱ͖ʹ౎౓ͳʹ͔

    ͔֬ΊΔඞཁ͕ແ͍
    

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41. ܕഁΓٕͦͷ
    ʙFOVNʙ
    

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42. enum Result {
    case Success(T)
    case Failure(NSError)
    init(_ value: T) {
    self = .Success(value)
    }
    init(_ error: NSError) {
    self = .Failure(error)
    }
    }
    enum
    

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43. ෳ਺ͷঢ়ଶΛऔΓ͏Δ
    • Aঢ়ଶͳΒaΛ࣋ͬͯΔ͚ͲɼBঢ়ଶͰ͸࣋ͬͯͳ͍
    • ͱΓ͋͑ͣAnyObjectʹͿͪࠐ·ͳ͍͍ͯ͘
    • ͲΕ͔ͻͱͭͷঢ়ଶ͔͠औΓಘͳ͍
    • A͔ͭBͳঢ়ଶ͸ଘࡏ͠ͳ͍
    

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44. ͭ·ΓResultͱ͸
    • ੒ޭ͔ࣦഊ͔ΛऔΓ͏Δ஋
    • ੒ޭͨ͠ΒT͕ɼࣦഊͨ͠ΒNSError͕ಘΒΕΔ
    • ୯७ʹOptional஋Λฒ΂Δͷʹൺ΂ͯѻ͍΍͍͢
    • ྆ํ஋͕͋Δ྆ํແ͍ͳΜͯ͜ͱ͸͋Γ͑ͳ͍
    

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45. func parse(JSON: AnyObject?) ->
    Result
    let JSON: AnyObject? = // ...
    let result = parse(JSON)
    switch result {
    case .Success(let user): // ...
    case .Failure(let error): // ...
    }
    

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46. +VTUB&JUIFS
    

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47. 0QUJPOBM
    

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48. Optional΋ಉྨ
    • Optional͸ͻͱͭͷgenericܕΛऔΔenum
    • enum Optional
    • ͳʹ͔ͷ஋͕͋Δ/ͳ͍ͷ2छྨͷঢ়ଶΛऔΓ͏Δ
    • SomeͩͬͨΒTΛ࣋ͬͯΔ
    • NoneͩͬͨΒnilΛ࣋ͬͯΔ
    

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49. 5IJTJTܕഁΓ
    

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50. ·ͱΊ
    

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51. ܕ͸ৼΔ෣͍ͱ஌Δ
    ܕͷ͋ΔϓϩάϥϜ
    ܕΛഁΔ
    

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52. ͋Γ͕ͱ͏͍͟͝·ͨ͠
    

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