構造的差分ライブラリ開発時の悲劇・喜劇

Transcript

1. ߏ଄తࠩ෼ϥΠϒϥϦ
 ։ൃ࣌ͷ൵ܶتܶ σόοάΛॿ͚Δ

2. ߏ଄తͳࠩ෼ͱ͸Կ͔ ·ͣ͸

3. func testExample1() { let a = Example( key1: "I'm not

   changed", key2: "I'm deleted" ) let b = Example( key1: "I'm not changed", key2: "I'm inserted" ) XCTAssertEqual(a, b) } Α͋͘Δ
   TUSVDU
   ͷൺֱ

4. XCTAssertEqual failed: ("Example(key1: "I\'m not changed", key2: "I\'m deleted")") is

   not equal to ("Example(key1: "I\'m not changed", key2: "I\'m inserted")") - ςετ݁Ռ͸ඇৗʹΘ͔ΓͮΒ͍

5. IUUQHJUIVCDPN,VOJXBL.JSSPS%J⒎,JU ͦ͜Ͱ

6. import MirrorDiffKit func testExample2() { let a = Example( key1:

   "I'm not changed", key2: "I'm deleted" ) let b = Example( key1: "I'm not changed", key2: "I'm inserted" ) XCTAssertEqual(a, b, diff(between: a, and: b)) } ࣦഊ࣌ͷϝοηʔδʹ
 .JSSPS%J⒎,JU
   ͷ
   EJ⒎
   Λࢦఆ .JSSPS%J⒎,JU
   Λ
   JNQPSU

7. struct Example { key1: "I'm not changed" - key2: "I'm

   deleted" + key2: "I'm inserted" } ͜Ε͕ߏ଄తͳࠩ෼
   ͙͢ʹࠩҟ͕Θ͔Γ·͢

8. [ "I'm not changed" "I'm not changed" - "I'm deleted"

   "I'm not changed" + "I'm inserted" ] ഑ྻͷॱংมߋͳͲ΋
 ߏ଄తͳࠩ෼Ͱ͢
   ͜Ε΋ݟ΍͘͢දࣔ͞Ε·͢

9. IUUQHJUIVCDPN,VOJXBL.JSSPS%J⒎,JU ΑΖ͓͘͠ئ͍͠·͢

10. ࢓૊Έͷղઆ ࠩ෼ܭࢉͷ

11. let example = Example( key1: "I'm not changed", key2: "I'm

    deleted" ) let hint = ( subject: Example.self, displayStyle: .struct, children: [ (label: "key1", value: "I'm not changed"), (label: "key2", value: "I'm deleted"), ] ) ߏ଄తͳࠩ෼ͷܭࢉʹ͸ɺ
 ࣍ͷΑ͏ͳΦϒδΣΫτͷ
 ߏ଄ͷώϯτ͕ෆՄܽͰ͢ ΦϒδΣΫτͷܕ ΦϒδΣΫτͷछྨ ϓϩύςΟͷ໊લͱ஋

12. ͦͷػೳΛ୲͏ͷ͕
    .JSSPS
 ʢඪ४ϥΠϒϥϦͷ
    "1*
    Ͱ͢ʣ

13. let example = Example( key1: "I'm not changed", key2: "I'm

    deleted" ) let mirror = Mirror(reflecting: example) let hint = ( subject: mirror.subjectType, displayStyle: mirror.displayStyle, children: mirror.children ) ௐ΂͍ͨΦϒδΣΫτ͔Β
 .JSSPS
    ΦϒδΣΫτΛ
 ࡞੒͢Δͱɺ ܕ৘ใ΍ΦϒδΣΫτͷछྨɺ
 ϓϩύςΟͷ໊લͱ஋ͳͲΛ
 ೖखͰ͖·͢

14. .JSSPS%J⒎,JU
    ͸ɺ
 ͜ͷ
    .JSSPS
    Λ࢖ͬͯ
 ࣮ݱ͞Ε͍ͯ·͢

15. ͍ΖΜͳ͜ͱ͕Ͱ͖ͦ͏Ͱ
 ເͷ޿͕Δ
    "1*
    Ͱ͢Ͷ

16. تܶ͸͜͜·Ͱͩ

17. ΍͹͍
    OJM
    ͕΍͹͍໰୊ ൵ܶͦͷ

18. struct Example { let any: Any? } let example =

    Example(any: nil) if let first = Mirror(reflecting: example) .children.first { print(first.value) } ϓϩύςΟΛ
    OJM
    ͰॳظԽ ϓϩύςΟͷ஋ΛݟΔͱɺ
 ઌ΄Ͳ
    OJM
    ͰॳظԽͨ͠ͷͰ
 OJM
    ʹͳ͍ͬͯΔ "OZ
    ͷϓϩύςΟ͕͋Δ
    TUSVDU .JSSPS
    Λ࡞੒ͯ͠ɺ
    TUSVDU
    ͷ
 ϓϩύςΟͷώϯτΛೖख

19. struct Example { let any: Any? } let example =

    Example(any: nil) if let first = Mirror(reflecting: example) .children.first { print(first.value == nil) print(first.value) } GBMTF 
    OJM
    Ͱ΋͔֬ΊͯΈΑ͏  ͔͠͠ೖ͍ͬͯΔͷ͸
    OJM
    ʜ

20. ߟ࡯ฤ ൵͠Έͷ

21. "OZ
    ʹ͸
 ͳΜͰ΋ೖΔ ᶃ Int String Bool Any

22. 0QUJPOBM
    ΋
 ೖΕΒΕΔ ᶄ Optional<T> Any

23. ͢Δͱ
    OJM
    ΋
 ೖΓ͏Δ ᶄ nil Any

24.  ᶄ nil Any == nil GBMTF

25. let x: Any? = nil let wrapper: Any = x

    // WARNING: Comparing non-optional value of // type 'Any' to nil always returns false print(x == nil) ࣮͸ղઆͨ͠ྫΛίʔυʹ͢Δͱܯࠂ͕ग़Δ ʮ0QUJPOBM
    ͡Όͳ͍஋ͱ
    OJM
    Λ
 ɹൺֱͯ͠΋ৗʹ
    GBMTF
    ͩΑʯ 

26. ͭ·Γɺ"OZ
    ʹ
    OJM
    Λ
 ೖΕͯ͸ͳΒͳ͍ͷͰ͢

27. ͔͠͠ɺ.JSSPS
    Ͱऔಘͨ͠
 ϓϩύςΟͷ஋ͷܕ͸
 ໰౴ແ༻Ͱ
    "OZ
    ͱ͍͏൵͠Έ
    ͳͷͰɺϓϩύςΟʹ
    OJM
    Λ΋ͭ
 ΦϒδΣΫτΛ.JSSPS
    ʹ͔͚Δͱ
 Ϋϥογϡͷةݥ͕͋Γ·͢

28. .JSSPS%J⒎,JU
    Ͱ͸͜ͷ໰୊ʹ
 ରॲ͍ͯ͠·͢ͷͰ҆͝৺Λʜ

29. ཁૉ਺
    ͷ
    UVQMF
    ໰୊ ൵ܶͦͷ

30. enum Example { case zero case one(key: String) case two(key1:

    String, key2: String) } 4XJGU
    Ͱ͸
    FOVN
    ͷ
    DBTF
    ʹ෇ଐ͢Δ஋ΛఆٛͰ͖·͢
    ͜ͷ෇ଐ͢Δ஋͸
    BTTPDJBUFE
    WBMVFT
    ͱݺ͹Ε͍ͯ·͢

31. enum Example { case one(key: String) case two(key1: String, key2:

    String) } func test() { let x1: Example = .one(key: "value") let x2: Example = .two(key1: "value1", key2: "value2") let mirror1 = Mirror(reflecting: x1) let mirror2 = Mirror(reflecting: x2) dump(mirror1.children.first!.value) dump(mirror2.children.first!.value) } ͦΕͧΕΛ
    .JSSPS
    ʹ͔͚·͢ ͜͜Ͱ͸
    BTTPDJBUFE
    WBMVFT
    ͷ
 ཁૉ਺͕ҟͳΔ
    ͭͷ
    DBTF
    Λ
 ఆٛ͠·͢ BTTPDJBUF
    WBMVFT
    ͸ɺ
 TUSVDU
    ͷϓϩύςΟͱ
 ಉ͡Α͏ʹ
    DIJMESFO
    Ͱ
 දݱ͞Ε·͢
    ͦΕͧΕͷ
    DIJMESFO
    Λ
 ֬ೝͯ͠Έ·͠ΐ͏

32. enum Example { case one(key: String) case two(key1: String, key2:

    String) } func test() { let x1: Example = .one(key: "value") let x2: Example = .two(key1: "value1", key2: "value2") let mirror1 = Mirror(reflecting: x1) let mirror2 = Mirror(reflecting: x2) dump(mirror1.children.first!.value) dump(mirror2.children.first!.value) } BTTPDJBUFE
    WBMVFT
    ͕
 ͭͷ৔߹
    
    
    
    
    
    
    
    
    
    
    
    WBMVF 
    ͭͷ৔߹

    
    
    
    

    
    
    
    
    
    
    
    LFZ
    WBMVF 

    
    
    
    
    
    
    
    LFZ
    WBMVF

    
    
    
    ܕ͕ҧ͏ 

33. ߟ࡯ฤ ൵͠Έͷ

34. let y: Any = (number: 123) print(type(of: y)) ܕΛௐ΂ͯΈΔͱ

    
    
    
    
    
    
    
    
    

    *OU ຊ౰͸
    BTTPDJBUFE
    WBMVFT
    ͷཁૉ਺͕
 ͍ͭ͘Ͱ͋ΕɺDIJMESFO
    ͷܕ͸
    UVQMF
    ʹ
 ͔ͨͬͨ͠ͷͰ͸ͱਪଌ
    ͔͠͠ɺཁૉ਺
    
    ͷ͚࣌ͩࣄ৘͕͋ͬͯ
 UVQMF
    ʹͰ͖ͳ͔͔ͬͨ΋͠Εͳ͍ͷͰɺ
 ࢼ͠ʹཁૉ͕
    
    ͭͷ
    UVQMF
    Λ࡞੒ͯ͠ΈΔ UVQMF
    Ͱ͸ͳ͍ 

35. // Error: cannot create a single-element tuple with // an

    element label let x: (number: Int) = (number: 123)
 
 let y: Any = (number: 123) print(type(of: y)) // Int ࣮͸ɺ4XJGU
    ͷܕͰ͸ཁૉ͕
    
    ͭͷ
    UVQMF
    ͸ఆٛͰ͖ͳ͍ ͔͠͠ɺཁૉ਺
    
    ͷ
    UVQMF
    ܕ͕
 ࡞Εͳ͍͚ͩͳͷͰɺܕΛ
 "OZ
    ʹͯ͠͠·͑͹ཁૉ਺
    
    ͷ
 UVQMF
    Β͖͠΋ͷΛఆٛͰ͖Δ ͔͠͠ɺఆٛͰ͖ͨͱͯ͠΋ɺ
 ͦͷܕ͸ཁૉͷத਎ͷܕʹ
 ͳΔΑ͏ͩ
    ͭ·Γɺཁૉ਺
    
    ͷ
    UVQMF
    ͸
 ଘࡏͰ͖ͳ͍͜ͱ͕Θ͔Δ

36. ཁૉ਺
    
    ͷ
    UVQMF
    ܕ͸ଘࡏͰ͖ͳ͍ͷͰɺ
 ຊདྷ͸
    UVQMF
    Ͱ͋Δ͸ͣͷ
 BTTPDJBUFE
    WBMVFT
    ͕ɺཁૉ਺
    
    ͷ
 ͱ͖ʹத਎͚ͩʹͳΔͷͰͨ͠ʜ

37. .JSSPS%J⒎,JU
    Ͱ͸͜ͷ໰୊ʹ
 ରॲ͍ͯ͠·͢ͷͰ҆͝৺Λʜ

38. ΧδϡΞϧʹյΕΔ ൵ܶͦͷ

39. ·ͱΊ w .JSSPS
    ͱ͍͏
    TUSVDU
    ͳͲͷߏ଄Λ
 ௐ΂ΔͨΊͷ
    "1*͕͋Γ·͢
    w ৭ʑͰ͖ͦ͏Ͱເ͕޿͕Γ·͢
    w ͔͠͠ɺ͔ͳΓͷͭΒΈ͕͋Γ·͢ͷͰ
 ΍͍ͬͯ͘ࡍʹ͸
    .JSSPS%J⒎,JU
    ͷ
 ճආྫΛࢀߟʹ͢ΔͱΑ͍Ͱ͠ΐ͏