"奇妙"なSwift

iOSDC2025 day2 LT

1.  lحົzͳ4XJGU !LOUL
   
   J04%$
   JPTED
   B
2. ͸͡Ίʹ w4XJGUʹ͸ଟ͘ͷจ๏ɾݴޠػೳ͕ଘࡏ
   w໌ࣔతɾ௚ײతͰ͋Δ͜ͱʹఆධ
3. ͸͡Ίʹ w4XJGUʹ͸ଟ͘ͷจ๏ɾݴޠػೳ͕ଘࡏ
   w໌ࣔతɾ௚ײతͰ͋Δ͜ͱʹఆධ
   wͨͩ͠Ԡ༻͢Δͱحົͳίʔυ΋ʜ
4. ͸͡Ίʹ [1, 2][{ _ in }]
5. ྫ [1, 2][{ _ in }]
6. ྫ [1, 2][{ _ in }] "SSBZ4MJDF*OU <
   >
7. [1, 2][{ _ in }] "SSBZ-JUFSBM ྫ
   จ๏
8. ྫ
   จ๏ [1, 2][{ _ in }] "SSBZ-JUFSBM 4VCTDSJQU$BMM $MPTVSF
9. ྫ
   จ๏ [1, 2][{ _ in }] "SSBZ-JUFSBM 4VCTDSJQU$BMM $MPTVSF subscript(_ f: (…) -> Void) -> … {}
10. ྫ
    จ๏ [1, 2][...] 6OCPVOEFE3BOHF
11. ྫ
    3BOHFͱTVCTDSJQU let range: Range<Int> =
12. let range: Range<Int> = 0..<1 // ..<͸RangeΛੜ੒͢Δԋࢉࢠ extension Comparable { public static func ..< (minimum: Self, maximum: Self) -> Range<Self> {} } ྫ
    3BOHFͱTVCTDSJQU
13. ྫ
    3BOHFͱTVCTDSJQU let range: Range<Int> = 0..<1 print([1, 2][range]) // ArraySlice<Int>([1]) // ..<͸RangeΛੜ੒͢Δԋࢉࢠ extension Comparable { public static func ..< (minimum: Self, maximum: Self) -> Range<Self> {} }
14. ྫ
    6OCPVOEFE3BOHFͩͱʜ let range: UnboundedRange<Int> = ... print([1, 2][range]) // ArraySlice<Int>([1, 2]) extension Comparable { public static func ... () -> UnboundedRange<Self> {} }
15. ྫ
    6OCPVOEFE3BOHFͩͱʜ let range: UnboundedRange<Int> = ... print([1, 2][range]) // ArraySlice<Int>([1, 2]) extension Comparable { public static func ... () -> UnboundedRange<Self> {} 🔴 }
16. ... ྫ
    6OCPVOEFE3BOHF public typealias UnboundedRange = (UnboundedRange_)->() public enum UnboundedRange_ { public static postfix func ... (_: UnboundedRange_) -> () { } }
17. ྫ
    6OCPVOEFE3BOHF public typealias UnboundedRange = (UnboundedRange_)->() public enum UnboundedRange_ { public static postfix func ... (_: UnboundedRange_) -> () { } } // ʮ...ʯ͸ؔ਺ͷࢀরͱͯ͠هड़ [1, 2][...]
18. ྫ
    6OCPVOEFE3BOHF public typealias UnboundedRange = (UnboundedRange_)->() public enum UnboundedRange_ { public static postfix func ... (_: UnboundedRange_) -> () { } } // ʮ...ʯ͸ؔ਺ͷࢀরͱͯ͠هड़ [1, 2][...] extension Collection { public subscript(x: UnboundedRange) -> SubSequence {} }
19. ྫ
    6OCPVOEFE3BOHF public typealias UnboundedRange = (UnboundedRange_)->() public enum UnboundedRange_ { public static postfix func ... (_: UnboundedRange_) -> () { } } // Ϋϩʔδϟʔ΋Ҿ਺ʹೖͬͯ͠·͏ʂ [1, 2][{ _ in }] extension Collection { public subscript(x: UnboundedRange) -> SubSequence {} }
20. ྫ
    Ԡ༻ typealias LastIndex = (LastIndex_) -> Void postfix operator ~ enum LastIndex_ { static postfix func ~(_ l: LastIndex_) -> Void {} } extension MutableCollection where Self: BidirectionalCollection { // shorthand of index(before: endIndex) subscript(_ l: LastIndex) -> Element { get { self[index(before: endIndex)] } set { self[index(before: endIndex)] = newValue } } }
21. ྫ
    Ԡ༻ typealias LastIndex = (LastIndex_) -> Void postfix operator ~ enum LastIndex_ { static postfix func ~(_ l: LastIndex_) -> Void {} } extension MutableCollection where Self: BidirectionalCollection { // shorthand of index(before: endIndex) subscript(_ l: LastIndex) -> Element { get { self[index(before: endIndex)] } set { self[index(before: endIndex)] = newValue } } } var array = [1, 2, 3] array[~] = 10
22. ྫ switch Int.random(in: 1..<100) { case { $0.isMultiple(of: 3) }: print("multiple of 3") case { $0.isMultiple(of: 5) }: print("multiple of 5") default: print("other") } func ~=<T>(evaluate: (T) -> Bool, rhs: T) -> Bool { evaluate(rhs) }
23. ྫ switch Int.random(in: 1..<100) { case { $0.isMultiple(of: 3) }: print("multiple of 3") case { $0.isMultiple(of: 5) }: print("multiple of 5") default: print("other") } func ~=<T>(evaluate: (T) -> Bool, rhs: T) -> Bool { evaluate(rhs) }
24. ྫ switch Int.random(in: 1..<100) { case { $0.isMultiple(of: 3) }: print("multiple of 3") case { $0.isMultiple(of: 5) }: print("multiple of 5") default: print("other") } func ~=<T>(evaluate: (T) -> Bool, rhs: T) -> Bool { evaluate(rhs) }
25. ྫ
    ύλʔϯϚονϯάԋࢉࢠ switch Int.random(in: 1..<100) { case { $0.isMultiple(of: 3) }: } switch Int.random(in: 1..<100) { case { $0.isMultiple(of: 3) }: }
26. ྫ
    ύλʔϯϚονϯάԋࢉࢠ switch Int.random(in: 1..<100) { case { $0.isMultiple(of: 3) }: } { $0.isMultiple(of: 3) } ~= Int.random(in: 1..<100) ίϯύΠϥ಺෦ͰಡΈସ͑ ˞FOVNͷύλʔϯϚον͸ผ
27. ྫ
    ύλʔϯϚονϯάԋࢉࢠ switch Int.random(in: 1..<100) { case { $0.isMultiple(of: 3) }: } { $0.isMultiple(of: 3) } ~= Int.random(in: 1..<100) func ~=<T>(evaluate: (T) -> Bool, rhs: T) -> Bool { evaluate(rhs) } ίϯύΠϥ಺෦ͰಡΈସ͑
28. ྫ
    Ԡ༻ extension Set { static func ~=(lhs: Set<Element>, rhs: Element) -> Bool { lhs.contains(rhs) } }
29. ྫ
    Ԡ༻ extension Set { static func ~=(lhs: Set<Element>, rhs: Element) -> Bool { lhs.contains(rhs) } } let vegitablesIDs: Set<Int> = [1, 2, 3] let fruitsIDs: Set<Int> = [4, 5, 6] func printPlantCategory(plantID: Int) { switch plantID { case vegitablesIDs: print("vegitables") case fruitsIDs: print("fruits") default: print("not vegitables nor fruits") } }
30. ྫ {String.init}()(“a",5)
31. ྫ {String.init}()(“a",5) String(”aaaaa”)
32. ྫ
    จ๏ {String.init}()(“a",5) ؔ਺ͷࢀর
33. ྫ
    จ๏ {String.init}()(“a",5) $MPTVSF
    
    'VODUJPO$BMM ؔ਺ͷࢀর
34. ྫ
    จ๏ {String.init}()(“a",5) ଈ࣮࣌ߦ$MPTVSF ؔ਺ͷࢀর
35. ྫ
    จ๏ {String.init}()(“a",5) 'VODUJPO$BMM ؔ਺ͷࢀর ଈ࣮࣌ߦ$MPTVSF
36. ྫ
    จ๏ {String.init}()(“a",5) ଈ࣮࣌ߦ$MPTVSF
37. ྫ
    จ๏ String.init(“a",5)
38. ྫ
    จ๏ String.init(“a",5) 🔴 Missing argument labels 'repeating:count:' in call init(repeating repeatedValue: String, count: Int)
39. ྫ
    Ҿ਺ϥϕϧͷ࡟আ String.init( repeating: "a", count: 5 )
40. ྫ
    Ҿ਺ϥϕϧͷ࡟আ {String.init}()(“a”,5)
41. ྫ
    Ԡ༻
42. ྫ
    Ԡ༻
43. ྫ
    Ԡ༻ String(repeating:a,count:5) // 28 {String.init}()(a,5) // 20
44. ͓ΘΓ wΈΜͳ΋حົͳ4XJGUΛݟ͚ͭΑ͏ʂ