SwiftUI時代のFunctional iOS Architecture / iOSDC Japan 2020

SwiftUI時代の Functional iOS Architecture by 稲見 泰宏 | トーク | iOSDC Japan 2020 - fortee.jp (Sep 21, 2020)
https://fortee.jp/iosdc-japan-2020/proposal/6d88c4dc-5a24-4c07-b505-65e2c389cdfb

Blog: https://zenn.dev/inamiy/articles/26b41ae9d81b83d5e9be
Book: https://zenn.dev/inamiy/books/795a2d9e6954abb46878

Transcript

1. SwiftUI ࣌୅ͷ
   Functional
   iOS Architecture
   2020/09/21 iOSDC Japan 2020
   Yasuhiro Inami / @inamiy
   

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5. ɹhttps://speakerdeck.com/inamiy/reactive-state-machine-japanese
   

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6. Reactive State Machine ͷৼΓฦΓ
   • MVVM ͔Β Redux / Elm Architecture (Mealy Machine) ΁
   • Reducer = (Action, State) -> (State, Output)
   • Output = Publisher
   • ΞϓϦͷσʔλϑϩʔΛ୯ํ޲ͷϧʔϓʹ୯७Խ͠ɺঢ়ଶ؅
   ཧͱςετΛ͠΍͘͢͢Δ
   • ෭࡞༻ (IO) ʹؔ਺ܕϦΞΫςΟϒϓϩάϥϛϯά (FRP) Λ༻
   ͍Δ
   

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7. Reactive State Machine ͷৼΓฦΓ
   • Proof of Concept
   • ReactiveAutomaton (ReactiveSwift൛)
   • RxAutomaton (RxSwift൛)
   • ͦͷଞ
   • React & Elm inspired frameworks in Swift
   • SwiftElmɿUIKit্ͷԾ૝ViewϑϨʔϜϫʔΫʢࢼݧ࣮૷ʣ
   

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8. ͋Ε͔Β4೥
   

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10. SwiftUI
    Combine
    

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12. Reactive State Machine ͷޙܧ࡞ʮHarvestʯΛΦʔϓϯιʔε
    

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13. ࠓ೔ͷΞδΣϯμ
    SwiftUI ࣌୅ͷ Functional iOS Architecture
    • inamiy/Harvest
    • pointfreeco/swift-composable-architecture
    • bow-swift/bow-arch
    • 3ͭͷϑϨʔϜϫʔΫͷڞ௨఺ͱҧ͍ʹ͍ͭͯ
    • ReactɺElm ͳͲͷWebϑϩϯτΤϯυͱͷൺֱ
    

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14. !
    Harvest
    

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15. !
    Harvest
    • Reactive State Machine (Elm Architecture෩) ࣮૷Λվྑ
    • SwiftUI + Combine ରԠ (HarvestStore)
    • Dependency Injection ίϯςφͱͯ͠΋ಇ͘
    • FRPʹΑΔ ෭࡞༻ͷΩϡʔ؅ཧ ͱΩϟϯηϧॲཧ
    • Optics (Lens & Prism) Λ࢖ͬͨ State ͱ Action ͷ෦඼Խͱ
    Reducer ͷ߹੒
    

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16. ෭࡞༻ΛΩϡʔͰ؅ཧ͢Δ
    • Publisher (Observable): ࣌ؒґଘͷ෭࡞༻ͷετϦʔϜ
    • ετϦʔϜͷετϦʔϜ ( Publisher> ) ͸ɺ
    ෭࡞༻ͷετϦʔϜΛʮΩϡʔ؅ཧʯ͍ͯ͠Δ͜ͱʹ૬౰
    • Ωϡʔ؅ཧ͞Ε༷ͨʑͳετϦʔϜΛҰຊͷετϦʔϜʹ౷
    ߹͢ΔʢʹϞφυ߹੒ɺϑϥοτԽʣ
    • Ωϡʔ؅ཧͷ ౷߹ઓུ (FlattenStrategy)
    • merge, concat, concurrent(max:), switchLatest, race ͳͲ
    

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19. Elm Architecture + FRP Λ૊Έ߹ΘͤΔར఺
    • FRPͷຊ࣭͸ɺ Publisher ಺෦ͷঢ়ଶΛӅṭ͠ͳ͕Βσʔλ
    ϑϩʔΛߏஙͰ͖Δ ͜ͱ
    • ͨͩ͠ɺঢ়ଶΛӅṭ͢Ε͹͢Δ΄Ͳɺঢ়ଶ؅ཧ͕೉͘͠ͳΔ
    • Elm Architecture ʢσʔλϑϩʔͷ؆қԽͱঢ়ଶ؅ཧͷ௥
    ٻʣΛϕʔεʹɺFRP Ͱʮͭ·Βͳ͍ঢ়ଶ؅ཧʯΛল͘
    • ྫɿ throttle ࣌ͷલճೖྗ࣌ࠁͷه࿥ɺલड़ͷΩϡʔ؅
    ཧ͞Εͨ෭࡞༻ͷ౷߹ܭࢉͳͲ
    

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20. Optics
    (Lens & Prism)
    

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21. Optics (Lens & Prism)
    • Lens: ঢ়ଶʢ௨ৗ͸ struct ௚ੵܕʣʹର͢Δ2ͭͷૢ࡞
    • ྫɿϢʔβʔ໊ͷऔಘ (get) ͱߋ৽ (set)
    • Prism: ΞΫγϣϯ (௨ৗ͸ enum ௚࿨ܕ) ʹର͢Δ2ͭͷૢ࡞
    • ྫɿ֤ case ͔ΒίϚϯυੜ੒ & Φϓγϣϯऔಘ (tryGet)
    struct User { enum Command {
    var name: String case rm(rf: Bool)
    } }
    

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22. struct Lens {
    /// struct ϝϯόม਺ͷऔಘ
    let get: (Whole) -> Part
    /// struct ϝϯόม਺ͷߋ৽
    let set: (Whole, Part) -> Whole
    }
    struct Prism {
    /// enum case ͷ associated values ͷऔಘ
    let tryGet: (Whole) -> Part?
    /// case ؔ਺ʢenum ίϯετϥΫλʣ
    let build: (Part) -> Whole
    }
    

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36. Lens ͱ Prism Λ࢖ͬͯ
    Reducerͷ
    ܕม׵ ʴ ߹੒͕Մೳ
    

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37. Reducer ͕߹੒ՄೳͳΒ͹
    ঢ়ଶͱΞΫγϣϯΛ
    ֤ίϯϙʔωϯτ͝ͱʹ
    ෼ղͯ͠ઃܭͰ͖Δ
    

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38. /// Reducer ͷ ChildState Λ ਌ State ʹม׵ʢ൓มؔखʣ
    func contramapS
    (_ lens: Lens) // ਌͔Βࢠ΁ͷࣹ
    -> Reducer // ࢠ͔Β
    -> Reducer // ਌΁ͷࣹ
    /// Reducer ͷ ChildAction Λ ਌ Action ʹม׵ʢ൓มؔखʣ
    func contramapA
    (_ prism: Prism) // ਌͔Βࢠ΁ͷࣹ
    -> Reducer // ࢠ͔Β
    -> Reducer // ਌΁ͷࣹ
    

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39. Reducer ͷܕม׵ͱ߹੒
    func combine(reducers: [Reducer]) { ... }
    let childReducer1: Reducer = ...
    let childReducer2: Reducer = ...
    // ࢠίϯϙʔωϯτ1,2ͷ Reducer Λ਌Λج४ʹม׵ͯ͠߹੒͢Δ
    let reducer: Reducer
    = combine([
    contramapS(lens1)(contramapA(prism1)(childReducer1))
    contramapS(lens2)(contramapA(prism2)(childReducer2))
    ])
    

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40. Optics ·ͱΊ
    • ΞϓϦͷ State (ओʹ struct) ͱ Action (ओʹ enum) Λڊେʹ
    ͤͣɺπϦʔߏ଄ʹ෼ղͯ͠ɺݸʑͷίϯϙʔωϯτ͝ͱʹ
    ؅ཧ͢Δʢૄ݁߹Խʣ
    • ݸʑͷίϯϙʔωϯτͷ Reducer Λશମʹ·ͱΊΔ ࡍʹ
    Lens ͱ Prism ͕׆༂͢Δ (react-reduxͷ্Ґ൛)
    • Optics ͸ ؔ਺ܕϓϩάϥϛϯάͱݍ࿦ Λ࢖ͬͨ୅දతͳς
    ΫχοΫͷ1ͭ
    

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44. Harvest-SwiftUI-
    Gallery
    https://github.com/inamiy/Harvest-SwiftUI-Gallery
    

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45. Composable
    Architecture
    

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46. Composable Architecture (TCA)
    • Point-Free νʔϜʹΑΔ Elm Architecture ෩ͷ࣮૷
    • Multi-Storeํࣜɿ ࠷্ҐͰ͸ͳ͘ɺ਌ʢ্ྲྀʣͱࢠʢԼ
    ྲྀʣίϯϙʔωϯτ֤ʑʹରͯ͠ϦΞΫςΟϒʹΠϕϯτ
    Λ఻ൖ͢Δ ʴ ॏෳ๷ࢭॲཧ
    • swift-case-paths Λ࢖ͬͨ Prism ࣮૷
    • Lens ͸Swiftඪ४ͷ WritableKeyPath Λ࢖ͬͯ୅༻
    • ˑ2000Ҏ্ɺυΩϡϝϯτͱϏσΦνϡʔτϦΞϧ͕ॆ࣮
    

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52. Case Paths
    struct User {
    var name: String
    }
    // WritableKeyPath
    let keyPath = \User.name // όοΫεϥογϡ
    enum Command {
    case rm(rf: Bool)
    }
    // CasePath
    let casePath = /Command.rm // ௨ৗͷεϥογϡ
    

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53. struct CasePath { // `Prism` ͱಉܕ
    let embed: (Value) -> Root
    let extract: (Root) -> Value?
    }
    prefix func / (
    embed: @escaping (Value) -> Root
    ) -> CasePath { /*
    !
    Magic inside */ }
    " prefix func / " ͷ಺෦࣮૷
    Swift ͷϦϑϨΫγϣϯΛ࢖ͬͯɺembedʢcaseؔ਺ʣ͔Β
    extract Λࣗಈతʹಋग़͢Δ (ར఺ɿcodegen͕ཁΒͳ͍)
    

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54. ৄࡉ͸ͪ͜ΒͷηογϣϯΛ͝ཡ͍ͩ͘͞
    

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55. Bow Arch
    

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56. Bow Arch
    • Tomás Ruiz-López ࢯ (47 Degrees ࣾ) ࡞ͷ UI Architecture
    • Bow: Lightweight Higher Kinded Polymorphism (ߴΧΠϯυ
    ଟ૬) Λ࢖ͬͨؔ਺ܕϓϩάϥϛϯά༻ϥΠϒϥϦ
    • func foo ͷΑ͏ͳॻ͖ํ͕Ͱ͖Δ
    • ࢀߟɿSwiftͰߴΧΠϯυଟ૬ - Speaker Deck
    • Comonadic UI: ݍ࿦ʢ਺ֶʣΛ࢖ͬͨUIઃܭख๏
    

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57. Comonadic UI
    

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58. ίϞφυ ≈ ΦϒδΣΫτࢦ޲ − Մมࢀর
    • SwiftUI.View Λ ίϞφυ ͱͯ͠ߟ͑Δ
    • ίϞφυ: (಺෦)ঢ়ଶΛ࣋ͪɺঢ়ଶ͔Βܭࢉͨ݁͠ՌΛฦ͢
    • ྫɿΠςϨʔλ͸ɺ಺෦ঢ়ଶΛߋ৽͠ͳ͕Β next Λग़ྗ
    • ྫɿϏϧμʔ͸ɺड͚औͬͨύϥϝʔλΛ಺෦ঢ়ଶʹอ࣋
    ͯ͠ɺ࠷ऴ݁ՌΛग़ྗ
    • ྫɿReact Component (SwiftUI) ͸ɺঢ়ଶΛ࣋ͪͭͭɺ
    render (body) ͰԾ૝DOM (View) Λग़ྗ
    

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59. struct Component: View {
    // ݱࡏͷঢ়ଶ
    var state: S
    // ݱࡏͷঢ়ଶ͔ΒԾ૝ViewΛܭࢉ
    let _body: (S) -> V
    // Note: static var Ͱߟ͑Δͱɺܕ͸ `Self -> V`
    var body: V { _body(state) }
    }
    Component = W ͱ͓͘ͱɺ
    body: W -> V ɾɾɾ ίϞφυʹॏཁͳ extract ͷੑ࣭
    

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64. // Ϟφυ M = UFʢίϯςΩετΛੜ੒͢Δܭࢉʣɹɹɹ// NOTEɿٙࣅSwift
    protocol Monad[M] where Functor[M] {
    static func `return`(_ c: C) -> M // η = unit
    static func join(_ mmc: M>) -> M
    // static func flatMap(_ f: C -> M)
    // -> M -> M
    }
    // ίϞφυ W = FUʢίϯςΩετΛফඅ͢Δܭࢉʣ
    protocol Comonad[W] where Functor[W] {
    static func extract(_ wd: W) -> D // ε = counit
    static func duplicate(_ wd: W) -> W>
    // static func extend(_ f: W -> D2)
    // -> W -> W
    }
    

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65. ίϞφυ (Comonad)
    // ٙࣅSwift
    protocol Comonad[W] where Functor[W] {
    static func extract(_ wd: W) -> D
    static func duplicate(_ wd: W) -> W>
    }
    • extract: ΦϒδΣΫτ W ͔ΒίϯςΩετΛফඅͯ͠ D
    Λग़ྗʢe.g. ঢ়ଶΛ࢖ͬͯ View Λग़ྗʣ
    • duplicate: ΦϒδΣΫτͷऔΓ͏ΔະདྷਤΛੜ੒ʢޙड़ʣ
    

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66. duplicate ͷΠϝʔδʢྫɿແݶετϦʔϜʣ
    let stream = [ 0, 1, 2, ... ] // ݱ࣌఺ͷແݶετϦʔϜ
    // ʢݱࡏͱະདྷͷʣແݶετϦʔϜΛཁૉʹ࣋ͭແݶετϦʔϜ
    duplicate(stream)
    = [ [ 0, 1, 2, ... ], // ݱࡏͷ `stream` Λෳ੡
    [ 1, 2, 3, ... ], // ෳ੡ + shift
    [ 2, 3, 4, ... ], // ෳ੡ + shift 2ճ
    [ 3, 4, 5, ... ], // ෳ੡ + shift 3ճ
    ... ]
    

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67. duplicate ͷΠϝʔδʢྫɿSwiftUI / Reactʣ
    let makeComp: (S) -> Component = Component(_body: ...) // ෦෼ద༻
    let component: Component = makeComp(state: ...) // ݱࡏͷ Component
    // ʢݱࡏͱະདྷͷʣComponent Λੜ੒͢Δ Component
    duplicate(component)
    = Component(_body: makeComp, state: component.state)
    ≈ [ /* ݱࡏͷ Component ͷෳ੡ */,
    /* ෳ੡ + ঢ়ଶͷҰ෦͕มߋ͞Εͨ Component */,
    /* ෳ੡ + ঢ়ଶͷผͷҰ෦͕มߋ͞Εͨ Component */,
    ... ] // Component ͕औΓ͏Δશͯͷঢ়ଶͷۭؒ
    

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68. Component ≅ Store ίϞφυ
    struct Component {
    // ݱࡏͷঢ়ଶ
    var state: S
    // ݱࡏͷঢ়ଶ͔ΒԾ૝ViewΛܭࢉ
    let _body: (S) -> V
    }
    struct Store {
    let state: S
    let render: (S) -> A
    }
    

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69. ࣮ࡍͷ ComponentʢΠϕϯτϋϯυϥ෇͖ʣ
    struct Component {
    // ݱࡏͷঢ়ଶ
    var state: S
    // ݱࡏͷঢ়ଶͱʮΠϕϯτϋϯυϥʯΛ౉ͯ͠Ծ૝ViewΛܭࢉ
    let view: (S) -> (EventHandler) -> V
    }
    typealias EventHandler = (Action) -> IO /* ෭࡞༻ */
    

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70. ͜͜Ͱɺ
    typealias UI = (EventHandler) -> V
    ͱ͓͘ͱɺ
    struct Component {
    var state: S
    let view: (S) -> UI
    }
    Component ͸ Store> ͱ͍͏ܗͰද͞ΕΔ
    

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71. ίϞφυͷ಺෦ঢ়ଶΛ֎͔Βૢ࡞͢Δ
    ઌ΄ͲͷແݶετϦʔϜͷྫͰ͸ɺ shift ʢ0, 1, 2, l߭Ďůሑ
    Ⅲ⴬۷ƑҠቔƎཌྷ֒čǸǠǟƵ൐ƆƂDžƾȀDSLͰදͤΔʣ
    // ແݶετϦʔϜʢίϞφυʣ // Shiftૢ࡞ʢϞφυʣ
    indirect enum Stream { indirect enum Shift {
    case cons(A, Stream) case done(A)
    } case shift(Shift)
    }
    Q. ͜ΕΒ2ͭͷܕ͸ͲͷΑ͏ͳؔ܎ʹ͋Δͷ͔ʁ
    

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72. A. Stream ίϞφυͱ Shift Ϟφυ͸ʮϖΞ (Pairing)ʯΛͳ͢
    protocol Pairing[F, G] {
    // ݍ࿦Ͱݴ͏ɺDayʢΞϓϦΧςΟϒʣ߹੒ੵ͔Β߃౳ؔख΁ͷࣗવม׵
    static func pair(f: (A, B) -> C) -> F -> G -> C
    }
    extension Pairing[Shift, Stream] {
    static func pair(f: (A, B) -> C) -> Shift -> Stream -> C {
    switch (shift, stream) {
    case let (.done(a), .cons(b, _)):
    return f(a, b)
    case let (.shift(nextShift), .cons(_, nextStream)):
    return pair(f)(nextShift)(nextStream)
    }
    }
    }
    

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73. Pairing Λ࢖͏ͱɺϞφυͰද͞ΕΔঢ়ଶૢ࡞ʹΑͬͯɺίϞ
    φυͷະདྷΛܾΊΔ͜ͱ͕Ͱ͖Δɻ
    // `stream` ͷະདྷΛ `shift` ͰܾΊΔ
    func select(shift: Shift<()>, stream: Stream) -> Stream {
    pair({ _, stream in stream })(shift)(duplicate(stream))
    }
    // Ұൠతʹɺ೚ҙͷϞφυɾίϞφυͷϖΞʹ͍ͭͯ੒Γཱͭ
    func select(monad: M<()>, comonad: W) -> W
    where Monad[M], Comonad[W], Pairing[M, W]
    {
    pair({ _, comonad in comonad })(monad)(duplicate(comonad))
    }
    

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74. ͳ͓ɺ SwiftUI ্ͷ ComponentʢStore ίϞφυʣͷ৔߹ɺঢ়
    ଶૢ࡞ͱͯ͠ State ϞφυΛ࢖͏͜ͱ͕Ͱ͖Δʢཧ༝͸ޙड़ʣ
    struct Store {
    let state: S
    let render: (S) -> A
    }
    struct State {
    let runState: S -> (A, S)
    }
    extension Pairing[State, Store] { ... }
    

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75. Stream ίϞφυ → Shift Ϟφυ
    Store ίϞφυ → State Ϟφυ
    Q. ίϞφυͷϖΞͱͳΔϞφυ͸
    ͲͷΑ͏ʹݟ͚ͭΔͷ͔ʁ
    

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76. // ݍ࿦Ͱݴ͏ɺComonadʹԊͬͨ߃౳ؔखͷӈKan Liftɻ
    // ೚ҙͷίϞφυ `W` ʹରԠ͢Δʢঢ়ଶૢ࡞ͷʣϞφυ `Co` Λߏ੒͢Δ͜ͱ͕Մೳɻ
    struct Co {
    let runCo: W R> -> R
    }
    extension Monad[Co] where Comonad[W] {
    static func `return`(_ c: C) -> Co {
    Co { wf in W.extract(wf)(c) }
    }
    static func join(_ mmc: Co>) -> Co
    Co { (wc2r: W R>) in
    mmc.runCo(
    W.extend({ wc2r in { (mc: Co) in mc.runCo(wc2r) } })(wc2r)
    )
    }
    }
    }
    

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77. Co Λ࢖͏ͱɺྫ͑͹
    Co, A> ≅ State ΛಘΔɻ
    ূ໌ɿ
    Co ≅ ∀R. W R> -> R ΑΓ
    Co, A>
    ≅ ∀R. Store R> -> R
    ≅ ∀R. (S, (S -> A -> R)) -> R
    ≅ S -> ∀R. ((S, A) -> R) -> R // ΧϦʔԽ
    ≅ S -> (S, A) // ถాͷิ୊
    ≅ State
    

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78. ͜͜·Ͱͷ੔ཧ (Comonadic UI)
    • ίϞφυͷ extract ʹΑͬͯɺঢ়ଶ͔ΒViewΛੜ੒͢Δ
    • ίϞφυͷ duplicate ʹΑͬͯɺUIͷະདྷਤΛ࡞Δ
    • ίϞφυͷϖΞͱͳΔ ঢ়ଶૢ࡞༻ͷϞφυΛ Co Ͱࢦ
    ఆ ͢Δ
    • select ͰίϞφυͱঢ়ଶૢ࡞༻ϞφυͷϖΞ͔Βɺ ະདྷͷ
    UI༻ίϞφυΛબ୒͢Δ
    

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79. ίϞφυ × ෭࡞༻ (IO)
    // ίϞφυΛϥοϓͯ͠ɺະདྷબ୒ͱ෭࡞༻ͷ࣮ߦʢՄมࢀরͷߋ৽ΛؚΉʣΛߦ͏
    class EffectComponent: ObservableObject where Comonad[W] {
    @Published var comonad: W>
    func explore() -> V {
    W.extract(comonad) { (action: IO>) in
    action.flatMap { (monad: Co) in
    let nextComonad = select(monad, self.comonad.duplicate())
    return IO.invoke {
    self.comonad = nextComonad
    }
    }
    }
    }
    }
    

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80. ίϞφυ × ෭࡞༻ = ΦϒδΣΫτࢦ޲ϓϩάϥϛϯά (OOP)
    • EffectComponent ͸ OOPʹ͓͚ΔʮΦϒδΣΫτʯ
    ʢͦͷෳࡶ͞ΛʮίϞφυʯͱʮ෭࡞༻ʯʹ෼ղ͢Δʣ
    • W = Store ίϞφυͷ৔߹ɺ ϖΞͱͳΔ ঢ়ଶϞφυͱͦΕʹ
    ൐͏෭࡞༻͸ɺ setState ʢঢ়ଶͷʮ௚઀ߋ৽ʯʣͱ౳Ձ
    • React ΍ SwiftUIʢ@State ͷՄมࢀরʣͷੈք؍ͱҰக
    • Note: ίϯϙʔωϯτͷωετ͸ɺίϞφυม׵ࢠΛ࢖͏
    

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81. Q. EffectComponent ͸ɺ
    ଞͷίϞφυ W ʹ΋࢖͑ΔͷͰ͸ʁ !
    

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82. Moore ίϞφυ
    indirect enum Moore { // I = ೖྗɺ A = ग़ྗ
    // ݱࡏͷग़ྗͱɺʮೖྗ͔ΒະདྷͷMooreίϞφυʯͷੜ੒ؔ਺
    case runMoore(A, I -> Moore)
    }
    ∃S. (initial: S, reducer: S -> I -> S, render: S ->
    A) ͱಉܕ (Moore State Machineɺঢ়ଶͷʮؒ઀ߋ৽ʯ)
    ࣮૷ྫɿ Elm Architecture, Redux
    

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83. ༨ࣗ༝ίϞφυ (Cofree)
    // ೚ҙͷؔख `F` ʹରͯ͠ɺίϞφυΛ࡞Δ͜ͱ͕Ͱ͖Δɻ
    // `F(X) = I -> X` ͷͱ͖ɺMooreɻ`F(X) = ()` ͷͱ͖ɺ㱽S.Storeɻ
    indirect enum Cofree {
    case runCofree(A, F>)
    }
    ϖΞͱͳΔࣗ༝Ϟφυ (Free) ͕ΫΤϦDSLʹͳΔ
    ࣮૷ྫɿ PureScript Halogen
    

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84. Comonad → Architecture
    Store → React
    Moore → Elm
    Cofree → PureScript
    

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85. ίϞφυ͸
    ΞʔΩςΫνϟʔΛ
    نఆ͢Δ
    

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86. View Slide

87. ·ͱΊ
    

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88. ·ͱΊ
    • SwiftUI ͷຊ࣭͸ ʮίϞφυʯ
    • ίϞφυͷߏ଄͕ UIΞʔΩςΫνϟʔͷύλʔϯ ΛܾΊΔ
    • React, Elm, PureScript Halogen, etc...
    • ঢ়ଶɺΞΫγϣϯɺ Reducer Λ֤ίϯϙʔωϯτ͝ͱʹ෼ղ
    ͠ɺ Optics Λ࢖ͬͯ·ͱΊ্͛Δ
    • ؔ਺ܕϓϩάϥϛϯάͱݍ࿦ɿ ຊ࣭Λཧղ͢Δڧྗͳख๏
    

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89. Harvest TCA Bow Arch
    GitHub Stars ˑ 300 ˑ 2000 ˑ 100
    ࡞ऀͷ΍Δؾ
    ❓
    ೉қ౓ Medium Medium Hard
    ෭࡞༻ Combine Combine BowEffects
    Optics FunOptics WritableKeyPath
    & CasePaths
    BowOptics
    Comonadic UI Moore Moore Any Comonads
    ӨڹΛड͚ͨݴޠ Elm Elm & React PureScript & ݍ࿦
    

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90. References (Libraries & Optics)
    •
    !
    Harvest: Apple's Combine.framework + State Machine,
    inspired by Elm
    • Composable Architecture
    • bow-arch: Comonadic UIs
    • Brandon Williams - Lenses in Swift
    • Lenses and Prisms in Swift: a pragmatic approach | Fun iOS
    

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91. References (Comonadic UI)
    • Declarative UIs are the Future — And the Future is
    Comonadic!
    • The Future Is Comonadic! - Speaker Deck
    • Comonads for user interfaces - Arthur Xavier
    • A Real-World Application with a Comonadic User Interface
    • The Comonad.Reader » Monads from Comonads
    

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92. References (෬ઢճऩ)
    • Reactive State Machine (Japanese) - Speaker Deck
    • SwiftͰElmΛ࡞Δ (Japanese) - Speaker Deck
    • SwiftͰߴΧΠϯυଟ૬ - Speaker Deck
    • ݍ࿦ͱSwift΁ͷԠ༻ / iOSDC Japan 2018 - Speaker Deck
    • ϓϩάϥϚͷͨΊͷϞφυ(ݍ࿦) - Speaker Deck
    • ݍ࿦ͱϓϩάϥϛϯά - Speaker Deck
    

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93. Thanks!
    Yasuhiro Inami
    @inamiy
    

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