20180410_iOSLT_SwiftとProtocol-OrientedProgramming

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1. SwiftͱProtocol-Oriented Programming 2018.4.10 Shota Nakagami / @shtnkgm
2. ຊ೔ͷΰʔϧ ϓϩτίϧࢦ޲Λ஌ͬͯɺ΋ͬͱSwiftyͳΤϯδχΞʹ
3. "Swift is a protocol-oriented language. " — David Abrahams @WWDC2015
4. Google Trendsʮprotocol-oriented programmingʯ
5. ϓϩτίϧΦϦΤϯςουͬͯͳΜͩΖ͏ʁ !
6. Protocol-Oriented Programming: POP • ༁͢ͱϓϩτίϧࢦ޲ϓϩάϥϛϯά • ϓϩτίϧࢦ޲ϓϩάϥϛϯά͸ϓϩάϥϛϯάύϥμΠϜͷ Ұͭ
7. ϓϩάϥϛϯάύϥμΠϜͬͯͳΜͩΖ͏ʁ !
8. Programming Paradigm • ϓϩάϥϛϯάΛ͢Δͱ͖ͷߟ͑ํɺํ๏࿦ͷ͜ͱ • ҰͭͷݴޠͰෳ਺ͷύϥμΠϜʹ෼ྨ͞ΕΔ͜ͱ΋͋Δ ʢ= ϚϧνύϥμΠϜʣ
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໨
10. iOSΞϓϦ։ൃ͸ϚϧνύϥμΠϜ • Objective-CɾɾɾΦϒδΣΫτࢦ޲ • Swiftɾɾɾϓϩτίϧࢦ޲ ʢΦϒδΣΫτࢦ޲&ؔ਺ܕ&δΣωϦοΫʣ • ಛʹɺUIKit͸ΦϒδΣΫτࢦ޲ͱͷؔΘΓ͕ڧ͍
11. ΦϒδΣΫτࢦ޲ͬͯͳΜ͚ͩͬʁ
12. ΦϒδΣΫτࢦ޲ͷ͓͞Β͍
13. Object-Oriented Programming: OOP • σʔλ΍ϝιουΛ࣋ͬͨΦϒδΣΫτΛͭͬͯͦ͘ͷ૬ޓ࡞ ༻ͰγεςϜΛܗ࡞Δ • ΦϒδΣΫτࢦ޲ͷࡾݪଇ • ϙϦϞʔϑΟζϜʢଟଶੑʣ • ΧϓηϧԽʢӅṭʣ • ܧঝ
14. UIKitͷΫϥε֊૚
16. ΦϒδΣΫτࢦ޲ͱϓϩτίϧࢦ޲
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
18. ΦϒδΣΫτࢦ޲Ͱʮಈ෺ʯΛσβΠϯͯ͠ΈΔ
19. ͍ΖΜͳಈ෺ΫϥεΛͭ͘Γ·͢
20. class Fish { } class Cat { } class Dog { } class Bird { }
21. Ͳͷಈ෺΋͝͸ΜΛ৯΂Δ →ॲཧΛڞ௨Խ͍ͨ͠
22. class Fish { func eat() { /* something */ } } class Cat { func eat() { /* something */ } } class Dog { func eat() { /* something */ } } class Bird { func eat() { /* something */ } }
23. ਌Ϋϥεʹڞ௨ॲཧΛ࣮૷ͯ͠ܧঝ
24. class Animal { func eat() { /* something */ } } class Fish: Animal { } class Cat: Animal { } class Dog: Animal { } class Bird: Animal { }
25. Ҡಈํ๏΋·ͱΊΒΕͦ͏ʁ
26. ਌Ϋϥεʹ࣮૷ʁ
27. class Animal { func eat() { /* something */ } func swim() { /* something */ } func run() { /* something */ } func fly() { /* something */ } } class Dog: Animal { } let dog = Dog() dog.fly()
28. class Animal { func eat() { /* something */ } func swim() { /* something */ } func run() { /* something */ } func fly() { /* something */ } } class Dog: Animal { } let dog = Dog() dog.fly()
29. ۭඈͿ͍͵͕ൃੜʢόάʣ
30. Ҡಈํ๏ʹ͍ͭͯͷந৅֓೦Λ࣮૷
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
32. ʊਓਓਓਓਓਓਓਓਓʊ ʼɹಥવͷ࢓༷มߋɹʻ ʉY^Y^Y^Y^Y^Y^Y^Yʉ
34. ӭ͛ͯ૸ΕΔΧΤϧ͸ʁ
36. Ϋϥε͸ଟॏܧঝΛαϙʔτ͍ͯ͠ͳ͍ // error: multiple inheritance from classes 'SwimAnimal' and 'RunAnimal' class Frog: SwimAnimal, RunAnimal { }
37. Ϋϥεͷܧঝʹؔ͢Δ໰୊ᶃ • ୯Ұʢ୯७ʣܧঝ͔͠Ͱ͖ͳ͍ͷͰɺΫϥεઃܭ͕೉͍͠ ɹˠ਌Ϋϥε͕ංେԽɺڽू౓͕௿͘ͳΓ͕ͪʢͪ͝Ό·ͥʣ
38. Ϋϥεͷܧঝʹؔ͢Δ໰୊ᶄ • ਌Ϋϥεͷมߋ͕શͯͷܧঝઌΫϥεʹ೾ٴ͢Δ ɹ →όάͷݪҼɺ਌Ϋϥε͸มߋ͠ʹ͍͘
39. Ϋϥεͷܧঝʹؔ͢Δ໰୊ᶅ • ந৅֓೦΋ΠϯελϯεԽͰ͖ͯ͠·͏ →όάͷݪҼ // ۩৅ΫϥεͷΠϯελϯεԽ let dog = Dog() let frog = Frog() // ந৅ΫϥεͷΠϯελϯεԽ let animal = Animal() // ͲΜͳಈ෺ʁ
40. Ϋϥεͷܧঝʹؔ͢Δ໰୊ᶆ • ΦʔόʔϥΠυલఏͷϝιου class Animal { func bark() { // ಈ෺ͱ͍͏֓೦͸ͳΜͯ໐͘?? // // } }
41. Ϋϥεͷܧঝʹؔ͢Δ໰୊ᶆ • ΦʔόʔϥΠυલఏͷϝιου class Animal { func bark() { // ಈ෺ͱ͍͏֓೦͸ͳΜͯ໐͘?? // ΦʔόʔϥΠυ͞Εͳ͍৔߹͸Ϋϥογϡͤ͞Δ͔... fatalError() } } ܧঝઌͰͷ࣮૷࿙Ε͕͋Δͱόάͷݩʹ
42. ϓϩτίϧࢦ޲Ͱʮಈ෺ʯΛσβΠϯͯ͠ΈΔ
43. Protocol Conformance ϓϩτίϧ४ڌʢద߹ʣ
44. ੑ࣭ΛϓϩτίϧͰදݱͯ͠४ڌ
45. protocol Eatable { func eat() } struct Cat: Eatable { // eatϝιουͷ࣮૷͕ڧ੍͞ΕΔ // ίϯύΠϥͰνΣοΫ͞ΕΔͷͰ҆શ func eat() { print("ͺ͘ͺ͘") } }
46. Protocol Extension ϓϩτίϧΤΫεςϯγϣϯʢ֦ுʣ
47. ϓϩτίϧΤΫεςϯγϣϯͰσϑΥϧτ࣮૷ protocol Eatable { func eat() } extension Eatable { func eat() { print("΋͙΋͙") } } struct Dog: Eatable { } let dog = Dog() dog.eat() // ΋͙΋͙
48. Protocol Composition ϓϩτίϧίϯϙδγϣϯʢ߹੒ʣ
49. ෳ਺ϓϩτίϧ४ڌͰΧΤϧ໰୊ղফ
50. struct Frog: Swimmable, Runnable { } let frog = Frog() frog.swim() frog.run()
51. Protocol Inheritance ϓϩτίϧܧঝ
52. ϓϩτίϧܧঝ΋Մೳ
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·͢
54. ͞ΒʹFlyableΛಈ෺Ͱͳ͍ܕͰ४ڌ • e.g. ඈߦػ • ඈͿͱ͍͏ੑ࣭͔Βઃܭ͢Δ͜ͱͰɺಈ෺ʹ΋ґଘ͠ͳ͍ • ॊೈͰ֦ுੑͷ͋ΔϓϩάϥϜʹͳΔ
55. ϓϩτίϧ͸஋ܕͰ΋࢖͑Δ • ஋ܕͷStruct΍Enumʹ͸ΫϥεͷΑ͏ͳܧঝػೳ͸ͳ͍͕ɺϓ ϩτίϧʹ͸४ڌͰ͖Δ • ஋ܕ͸ࢀরܕʢΫϥεʣΑΓ΋҆શ • ஋Λڞ༗͠ͳ͍ͷͰҙਤ͠ͳ͍஋ͷมߋ͕ൃੜ͠ͳ͍ • εϨουηʔϑ • ॥؀ࢀর໰୊͕ൃੜ͠ͳ͍
56. ϓϩτίϧ͸ܕͱͯ͠ѻ͑Δ • ϙϦϞʔϑΟζϜͰૄ݁߹ʹ ! func feed(eatable: Eatable) • ΠϯελϯεԽෆՄ ! // Error: Protocol type 'Eatable' cannot be instantiated let eatable = Eatable()
57. δΣωϦΫεʢ૯শܕʣ΋࢖͑Δ Ϋϥε΍StructͷΑ͏ͳܕύϥϝʔλ<T>͸࢖͑ͳ͍͕ɺ associatedtypeͰ૯শܕΛఆٛͰ͖Δ class Eatable<FoodType> { } struct Eatable<FoodType> { } protocol Eatable { associatedtype FoodType }
58. protocol Eatable { associatedtype FoodType func eat(food: FoodType) } struct Bird: Eatable { typealias FoodType = Fish func eat(food: FoodType) { // do something } }
59. ϓϩτίϧࢦ޲͍͍Ͷ
60. ·ͱΊ
61. ࠷ڧͷϓϩάϥϛϯάύϥμΠϜ͸ͳ͍ • ͲΕ΋໰୊ղܾͷखஈͷҰͭʹ͗͢ͳ͍ • ϓϩτίϧࢦ޲Λ஌Δ͜ͱͰϓϩάϥϛϯάͷ෯͕޿͕Δ • ͍ΖΜͳํ๏࿦Λ஌Γɺదࡐదॴ࢖͑Δͷ͕࠷ڧ
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
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
64. ͓ΘΓ