構造的差分ライブラリ開発時の悲劇・喜劇

https://iosdc-reject-conference.connpass.com/event/64175/

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
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   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
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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
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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
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 ೖखͰ͖·͢
14. .JSSPS%J⒎,JU
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15. ͍ΖΜͳ͜ͱ͕Ͱ͖ͦ͏Ͱ
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16. تܶ͸͜͜·Ͱͩ
17. ΍͹͍
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18. struct Example { let any: Any? } let example = Example(any: nil) if let first = Mirror(reflecting: example) .children.first { print(first.value) } ϓϩύςΟΛ
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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 
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20. ߟ࡯ฤ ൵͠Έͷ
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 ͳΜͰ΋ೖΔ ᶃ Int String Bool Any
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23. ͢Δͱ
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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
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26. ͭ·Γɺ"OZ
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27. ͔͠͠ɺ.JSSPS
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28. .JSSPS%J⒎,JU
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29. ཁૉ਺
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30. enum Example { case zero case one(key: String) case two(key1: String, key2: String) } 4XJGU
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    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
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 TUSVDU
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    Ͱ
 දݱ͞Ε·͢
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    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
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33. ߟ࡯ฤ ൵͠Έͷ
34. let y: Any = (number: 123) print(type(of: y)) ܕΛௐ΂ͯΈΔͱ

    
    
    
    
    
    
    
    
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 UVQMF
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    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
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 ࡞Εͳ͍͚ͩͳͷͰɺܕΛ
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36. ཁૉ਺
    
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38. ΧδϡΞϧʹյΕΔ ൵ܶͦͷ
39. ·ͱΊ w .JSSPS
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 ճආྫΛࢀߟʹ͢ΔͱΑ͍Ͱ͠ΐ͏