20180410_iOSLT_SwiftとProtocol-OrientedProgramming

Transcript

1. SwiftͱProtocol-Oriented
   Programming
   2018.4.10
   Shota Nakagami / @shtnkgm
   

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2. ຊ೔ͷΰʔϧ
   ϓϩτίϧࢦ޲Λ஌ͬͯɺ΋ͬͱSwiftyͳΤϯδχΞʹ
   

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3. "Swift is a protocol-oriented
   language. "
   — David Abrahams @WWDC2015
   

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4. Google Trendsʮprotocol-oriented programmingʯ
   

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5. ϓϩτίϧΦϦΤϯςουͬͯͳΜͩΖ͏ʁ
   !
   

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6. Protocol-Oriented Programming: POP
   • ༁͢ͱϓϩτίϧࢦ޲ϓϩάϥϛϯά
   • ϓϩτίϧࢦ޲ϓϩάϥϛϯά͸ϓϩάϥϛϯάύϥμΠϜͷ
   Ұͭ
   

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7. ϓϩάϥϛϯάύϥμΠϜͬͯͳΜͩΖ͏ʁ
   !
   

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8. Programming Paradigm
   • ϓϩάϥϛϯάΛ͢Δͱ͖ͷߟ͑ํɺํ๏࿦ͷ͜ͱ
   • ҰͭͷݴޠͰෳ਺ͷύϥμΠϜʹ෼ྨ͞ΕΔ͜ͱ΋͋Δ
   ʢ= ϚϧνύϥμΠϜʣ
   

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9. ϓϩάϥϛϯάύϥμΠϜͷҰྫ
   ϓϩάϥϛϯάύϥμΠϜ ֓ཁ
   खଓ͖ܕʢProceduralʣ ঢ়ଶΛ࣋ͪɺҰ࿈ͷॲཧΛؔ਺ʹ·ͱΊΔ
   ΦϒδΣΫτࢦ޲ʢObject-Orientedʣ σʔλ΍ৼΔ෣͍ΛΦϒδΣΫτʹ࣋ͨͤΔ
   ؔ਺ܕʢFunctionalʣ ঢ়ଶ΍෭࡞༻Λ࣋ͨͳ͍ؔ਺Λ૊Έ߹ΘͤΔ
   ϦΞΫςΟϒʢReactiveʣ σʔλͷྲྀΕʢdata flowʣͱσʔλͷมԽͷ
   ఻೻ʹண໨
   δΣωϦοΫʢGenericʣ σʔλܗࣜʹґଘ͠ͳ͍
   ΞεϖΫτࢦ޲ʢAspect-Orientedʣ ԣஅతؔ৺ࣄͷ෼཭ʹண໨
   

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10. iOSΞϓϦ։ൃ͸ϚϧνύϥμΠϜ
    • Objective-CɾɾɾΦϒδΣΫτࢦ޲
    • Swiftɾɾɾϓϩτίϧࢦ޲
    ʢΦϒδΣΫτࢦ޲&ؔ਺ܕ&δΣωϦοΫʣ
    • ಛʹɺUIKit͸ΦϒδΣΫτࢦ޲ͱͷؔΘΓ͕ڧ͍
    

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11. ΦϒδΣΫτࢦ޲ͬͯͳΜ͚ͩͬʁ
    

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12. ΦϒδΣΫτࢦ޲ͷ͓͞Β͍
    

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13. Object-Oriented Programming: OOP
    • σʔλ΍ϝιουΛ࣋ͬͨΦϒδΣΫτΛͭͬͯͦ͘ͷ૬ޓ࡞
    ༻ͰγεςϜΛܗ࡞Δ
    • ΦϒδΣΫτࢦ޲ͷࡾݪଇ
    • ϙϦϞʔϑΟζϜʢଟଶੑʣ
    • ΧϓηϧԽʢӅṭʣ
    • ܧঝ
    

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14. UIKitͷΫϥε֊૚
    

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16. ΦϒδΣΫτࢦ޲ͱϓϩτίϧࢦ޲
    

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17. Swift Standard Framework͸΄΅ߏ଄ମͰߏ੒
    ओͳߏ੒ཁૉ
    ΦϒδΣΫτࢦ޲ ϓϩτίϧࢦ޲
    ܕ ࢀরܕʢClassʣ ஋ܕʢStruct/Enumʣ
    ந৅Խ Superclass Protocol
    →Obective-C࣌୅ͷΫϥεͷར༻͔Βߏ଄ମͷར༻͕த৺ʹ
    

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18. ΦϒδΣΫτࢦ޲Ͱʮಈ෺ʯΛσβΠϯͯ͠ΈΔ
    

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19. ͍ΖΜͳಈ෺ΫϥεΛͭ͘Γ·͢
    

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20. class Fish {
    }
    class Cat {
    }
    class Dog {
    }
    class Bird {
    }
    

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21. Ͳͷಈ෺΋͝͸ΜΛ৯΂Δ
    →ॲཧΛڞ௨Խ͍ͨ͠
    

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22. class Fish {
    func eat() { /* something */ }
    }
    class Cat {
    func eat() { /* something */ }
    }
    class Dog {
    func eat() { /* something */ }
    }
    class Bird {
    func eat() { /* something */ }
    }
    

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23. ਌Ϋϥεʹڞ௨ॲཧΛ࣮૷ͯ͠ܧঝ
    

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24. class Animal {
    func eat() { /* something */ }
    }
    class Fish: Animal {
    }
    class Cat: Animal {
    }
    class Dog: Animal {
    }
    class Bird: Animal {
    }
    

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25. Ҡಈํ๏΋·ͱΊΒΕͦ͏ʁ
    

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26. ਌Ϋϥεʹ࣮૷ʁ
    

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27. class Animal {
    func eat() { /* something */ }
    func swim() { /* something */ }
    func run() { /* something */ }
    func fly() { /* something */ }
    }
    class Dog: Animal {
    }
    let dog = Dog()
    dog.fly()
    

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28. class Animal {
    func eat() { /* something */ }
    func swim() { /* something */ }
    func run() { /* something */ }
    func fly() { /* something */ }
    }
    class Dog: Animal {
    }
    let dog = Dog()
    dog.fly()
    

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29. ۭඈͿ͍͵͕ൃੜʢόάʣ
    

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30. Ҡಈํ๏ʹ͍ͭͯͷந৅֓೦Λ࣮૷
    

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31. ΑΓ҆શͳϓϩάϥϜʹ
    class Animal {
    func eat() { /* something */ }
    }
    class RunAnimal: Animal {
    func run() { /* something */ }
    }
    class Dog: RunAnimal {
    }
    let dog = Dog()
    dog.run() // OK
    dog.fly() // ίϯύΠϧΤϥʔ
    

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32. ʊਓਓਓਓਓਓਓਓਓʊ
    ʼɹಥવͷ࢓༷มߋɹʻ
    ʉY^Y^Y^Y^Y^Y^Y^Yʉ
    

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34. ӭ͛ͯ૸ΕΔΧΤϧ͸ʁ
    

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36. Ϋϥε͸ଟॏܧঝΛαϙʔτ͍ͯ͠ͳ͍
    // error: multiple inheritance from classes 'SwimAnimal' and 'RunAnimal'
    class Frog: SwimAnimal, RunAnimal {
    }
    

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37. Ϋϥεͷܧঝʹؔ͢Δ໰୊ᶃ
    • ୯Ұʢ୯७ʣܧঝ͔͠Ͱ͖ͳ͍ͷͰɺΫϥεઃܭ͕೉͍͠
    ɹˠ਌Ϋϥε͕ංେԽɺڽू౓͕௿͘ͳΓ͕ͪʢͪ͝Ό·ͥʣ
    

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38. Ϋϥεͷܧঝʹؔ͢Δ໰୊ᶄ
    • ਌Ϋϥεͷมߋ͕શͯͷܧঝઌΫϥεʹ೾ٴ͢Δ
    ɹ →όάͷݪҼɺ਌Ϋϥε͸มߋ͠ʹ͍͘
    

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39. Ϋϥεͷܧঝʹؔ͢Δ໰୊ᶅ
    • ந৅֓೦΋ΠϯελϯεԽͰ͖ͯ͠·͏
    →όάͷݪҼ
    // ۩৅ΫϥεͷΠϯελϯεԽ
    let dog = Dog()
    let frog = Frog()
    // ந৅ΫϥεͷΠϯελϯεԽ
    let animal = Animal() // ͲΜͳಈ෺ʁ
    

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40. Ϋϥεͷܧঝʹؔ͢Δ໰୊ᶆ
    • ΦʔόʔϥΠυલఏͷϝιου
    class Animal {
    func bark() {
    // ಈ෺ͱ͍͏֓೦͸ͳΜͯ໐͘??
    //
    //
    }
    }
    

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41. Ϋϥεͷܧঝʹؔ͢Δ໰୊ᶆ
    • ΦʔόʔϥΠυલఏͷϝιου
    class Animal {
    func bark() {
    // ಈ෺ͱ͍͏֓೦͸ͳΜͯ໐͘??
    // ΦʔόʔϥΠυ͞Εͳ͍৔߹͸Ϋϥογϡͤ͞Δ͔...
    fatalError()
    }
    }
    ܧঝઌͰͷ࣮૷࿙Ε͕͋Δͱόάͷݩʹ
    

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42. ϓϩτίϧࢦ޲Ͱʮಈ෺ʯΛσβΠϯͯ͠ΈΔ
    

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43. Protocol Conformance
    ϓϩτίϧ४ڌʢద߹ʣ
    

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44. ੑ࣭ΛϓϩτίϧͰදݱͯ͠४ڌ
    

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45. protocol Eatable {
    func eat()
    }
    struct Cat: Eatable {
    // eatϝιουͷ࣮૷͕ڧ੍͞ΕΔ
    // ίϯύΠϥͰνΣοΫ͞ΕΔͷͰ҆શ
    func eat() {
    print("ͺ͘ͺ͘")
    }
    }
    

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46. Protocol Extension
    ϓϩτίϧΤΫεςϯγϣϯʢ֦ுʣ
    

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47. ϓϩτίϧΤΫεςϯγϣϯͰσϑΥϧτ࣮૷
    protocol Eatable {
    func eat()
    }
    extension Eatable {
    func eat() {
    print("΋͙΋͙")
    }
    }
    struct Dog: Eatable { }
    let dog = Dog()
    dog.eat() // ΋͙΋͙
    

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48. Protocol Composition
    ϓϩτίϧίϯϙδγϣϯʢ߹੒ʣ
    

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49. ෳ਺ϓϩτίϧ४ڌͰΧΤϧ໰୊ղফ
    

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50. struct Frog: Swimmable, Runnable {
    }
    let frog = Frog()
    frog.swim()
    frog.run()
    

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51. Protocol Inheritance
    ϓϩτίϧܧঝ
    

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52. ϓϩτίϧܧঝ΋Մೳ
    

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53. protocol Movable {
    func move(method: String)
    }
    extension Movable {
    func move(method: String) {
    print(method + "ਐΈ·͢")
    }
    }
    protocol Swimmable: Movable {
    func swim()
    }
    extension Swimmable {
    func swim() {
    move(method: "ӭ͍Ͱ")
    }
    }
    struct Fish: Swimmable { }
    let fish = Fish()
    fish.swim() // ӭ͍ͰਐΈ·͢
    

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54. ͞ΒʹFlyableΛಈ෺Ͱͳ͍ܕͰ४ڌ
    • e.g. ඈߦػ
    • ඈͿͱ͍͏ੑ࣭͔Βઃܭ͢Δ͜ͱͰɺಈ෺ʹ΋ґଘ͠ͳ͍
    • ॊೈͰ֦ுੑͷ͋ΔϓϩάϥϜʹͳΔ
    

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55. ϓϩτίϧ͸஋ܕͰ΋࢖͑Δ
    • ஋ܕͷStruct΍Enumʹ͸ΫϥεͷΑ͏ͳܧঝػೳ͸ͳ͍͕ɺϓ
    ϩτίϧʹ͸४ڌͰ͖Δ
    • ஋ܕ͸ࢀরܕʢΫϥεʣΑΓ΋҆શ
    • ஋Λڞ༗͠ͳ͍ͷͰҙਤ͠ͳ͍஋ͷมߋ͕ൃੜ͠ͳ͍
    • εϨουηʔϑ
    • ॥؀ࢀর໰୊͕ൃੜ͠ͳ͍
    

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56. ϓϩτίϧ͸ܕͱͯ͠ѻ͑Δ
    • ϙϦϞʔϑΟζϜͰૄ݁߹ʹ
    !
    func feed(eatable: Eatable)
    • ΠϯελϯεԽෆՄ
    !
    // Error: Protocol type 'Eatable' cannot be instantiated
    let eatable = Eatable()
    

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57. δΣωϦΫεʢ૯শܕʣ΋࢖͑Δ
    Ϋϥε΍StructͷΑ͏ͳܕύϥϝʔλ͸࢖͑ͳ͍͕ɺ
    associatedtypeͰ૯শܕΛఆٛͰ͖Δ
    class Eatable { }
    struct Eatable { }
    protocol Eatable {
    associatedtype FoodType
    }
    

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58. protocol Eatable {
    associatedtype FoodType
    func eat(food: FoodType)
    }
    struct Bird: Eatable {
    typealias FoodType = Fish
    func eat(food: FoodType) {
    // do something
    }
    }
    

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59. ϓϩτίϧࢦ޲͍͍Ͷ
    

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60. ·ͱΊ
    

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61. ࠷ڧͷϓϩάϥϛϯάύϥμΠϜ͸ͳ͍
    • ͲΕ΋໰୊ղܾͷखஈͷҰͭʹ͗͢ͳ͍
    • ϓϩτίϧࢦ޲Λ஌Δ͜ͱͰϓϩάϥϛϯάͷ෯͕޿͕Δ
    • ͍ΖΜͳํ๏࿦Λ஌Γɺదࡐదॴ࢖͑Δͷ͕࠷ڧ
    

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62. ΦϒδΣΫτࢦ޲ ϓϩτίϧࢦ޲
    σʔλͷ҉໧తڞ༗ ×ʢ͋Γʣ ○ʢͳ͠ʣ
    ந৅Խ ○ʢSuperclassʣ ○ʢProtocolʣ
    ίϯϙδγϣϯ ×ʢͰ͖ͳ͍ʣ ○ʢProtocol Compositionʣ
    ந৅ܕͷΠϯελϯεԽ ×ʢͰ͖Δʣ ○ʢͰ͖ͳ͍ʣ
    σϑΥϧτ࣮૷ ○ʢSuperclassʣ ○ʢProtocol Extensionʣ
    ۩৅ܕ΁ͷ࣮૷ͷڧ੍ ×ʢಈతνΣοΫʣ ○ʢ੩తνΣοΫʣ
    ϙϦϞʔϑΟζϜ ○ʢSuperclassʣ ○ʢProtocolʣ
    δΣωϦΫε ○ʢܕύϥϝʔλʣ ○ʢassociatedtypeʣ
    UIKitΦϒδΣΫτͷܧঝ ○ʢͰ͖Δʣ ×ʢͰ͖ͳ͍ʣ
    ϥΠϑαΠΫϧ؅ཧʢdeinitʣ ○ʢ͋Γʣ ×ʢͳ͠ʣ
    Ұҙੑͷ͋Δσʔλʢsingletonʣ ○ʢ࡞Γ΍͍͢ʣ ×ʢ࡞Γʹ͍͘ʣ
    

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63. ΑΓৄ͘͠
    • WWDC2015ηογϣϯಈը
    Protocol-Oriented Programming in
    Swift / WWDC2015
    • ެࣜϦϑΝϨϯε
    Protocols / The Swift Programming
    Language (Swift 4.1)
    • ॻ੶
    Swift 4 Protocol-Oriented Programming
    - Third Edition
    

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64. ͓ΘΓ
    

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