mirror of
https://github.com/pointfreeco/swift-composable-architecture.git
synced 2025-12-14 20:35:56 +01:00
c99a2f9636
* Update Tic-Tac-Toe to use enum state * wip * more swift compatability changes Co-authored-by: Brandon Williams <mbrandonw@hey.com>
620 lines
18 KiB
Swift
620 lines
18 KiB
Swift
import SwiftUI
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/// A view that can switch over a store of enum state and handle each case.
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///
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/// An application may model parts of its state with enums. For example, app state may differ if a
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/// user is logged-in or not:
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///
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/// enum AppState {
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/// case loggedIn(LoggedInState)
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/// case loggedOut(LoggedOutState)
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/// }
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///
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/// In the view layer, a store on this state can switch over each case using a `SwitchStore` and
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/// a `CaseLet` view per case:
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///
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/// struct AppView: View {
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/// let store: Store<AppState, AppAction>
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///
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/// var body: some View {
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/// SwitchStore(self.store) {
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/// CaseLet(state: /AppState.loggedIn, action: AppAction.loggedIn) { loggedInStore in
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/// LoggedInView(store: loggedInStore)
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/// }
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/// CaseLet(state: /AppState.loggedOut, action: AppAction.loggedOut) { loggedOutStore in
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/// LoggedOutView(store: loggedOutStore)
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/// }
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/// }
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/// }
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/// }
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///
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/// If a `SwitchStore` does not exhaustively handle every case with a corresponding `CaseLet` view,
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/// a debug breakpoint will be raised when an unhandled case is encountered. To fall back on a
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/// default view instead, introduce a `Default` view at the end of the `SwitchStore`:
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///
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/// SwitchStore(self.store) {
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/// CaseLet(state: /MyState.first, action: MyAction.first, then: FirstView.init(store:))
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/// CaseLet(state: /MyState.second, action: MyAction.second, then: SecondView.init(store:))
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///
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/// Default {
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/// Text("State is neither first nor second.")
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/// }
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/// }
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///
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/// - See also: `Reducer.pullback`, a method that aids in transforming reducers that operate on each
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/// case of an enum into reducers that operate on the entire enum.
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///
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public struct SwitchStore<State, Action, Content>: View where Content: View {
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public let store: Store<State, Action>
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public let content: () -> Content
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init(
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store: Store<State, Action>,
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@ViewBuilder content: @escaping () -> Content
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) {
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self.store = store
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self.content = content
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}
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public var body: some View {
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self.content()
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.environmentObject(StoreObservableObject(store: self.store))
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}
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}
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/// A view that handles a specific case of enum state in a `SwitchStore`.
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public struct CaseLet<GlobalState, GlobalAction, LocalState, LocalAction, Content>: View
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where Content: View {
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@EnvironmentObject private var store: StoreObservableObject<GlobalState, GlobalAction>
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public let toLocalState: (GlobalState) -> LocalState?
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public let fromLocalAction: (LocalAction) -> GlobalAction
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public let content: (Store<LocalState, LocalAction>) -> Content
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/// Initializes a `CaseLet` view that computes content depending on if a store of enum state
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/// matches a particular case.
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///
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/// - Parameters:
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/// - toLocalState: A case path that can extract a case of switch store state.
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/// - fromLocalAction: A function that can embed a case action in a switch store action.
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/// - content: A function that is given a store of the given case's state and returns a view
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/// that is visible only when the switch store's state matches.
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public init(
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state toLocalState: @escaping (GlobalState) -> LocalState?,
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action fromLocalAction: @escaping (LocalAction) -> GlobalAction,
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@ViewBuilder then content: @escaping (Store<LocalState, LocalAction>) -> Content
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) {
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self.toLocalState = toLocalState
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self.fromLocalAction = fromLocalAction
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self.content = content
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}
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public var body: some View {
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IfLetStore(
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self.store.wrappedValue.scope(
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state: self.toLocalState,
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action: self.fromLocalAction
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),
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then: self.content
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)
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}
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}
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/// A view that covers any cases that aren't addressed in a `SwitchStore`.
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///
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/// If you wish to use `SwitchStore` in a non-exhaustive manner (i.e. you do not want to provide
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/// a `CaseLet` for each case of the enum), then you must insert a `Default` view at the end of
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/// the `SwitchStore`'s body.
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public struct Default<Content>: View where Content: View {
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private let content: () -> Content
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/// Initializes a `Default` view that computes content depending on if a store of enum state does
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/// not match a particular case.
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///
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/// - Parameter content: A function that returns a view that is visible only when the switch
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/// store's state does not match a preceding `CaseLet` view.
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public init(@ViewBuilder content: @escaping () -> Content) {
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self.content = content
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}
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public var body: some View {
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self.content()
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}
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}
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extension SwitchStore {
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public init<State1, Action1, Content1, DefaultContent>(
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_ store: Store<State, Action>,
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@ViewBuilder content: @escaping () -> TupleView<
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(
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CaseLet<State, Action, State1, Action1, Content1>,
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Default<DefaultContent>
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)
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>
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)
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where
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Content == WithViewStore<
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State,
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Action,
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_ConditionalContent<
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CaseLet<State, Action, State1, Action1, Content1>,
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Default<DefaultContent>
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>
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>
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{
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self.init(store: store) {
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let content = content().value
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return WithViewStore(store, removeDuplicates: { enumTag($0) == enumTag($1) }) { viewStore in
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if content.0.toLocalState(viewStore.state) != nil {
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content.0
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} else {
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content.1
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}
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}
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}
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}
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public init<State1, Action1, Content1>(
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_ store: Store<State, Action>,
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file: StaticString = #file,
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line: UInt = #line,
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@ViewBuilder content: @escaping () -> CaseLet<State, Action, State1, Action1, Content1>
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)
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where
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Content == WithViewStore<
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State,
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Action,
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_ConditionalContent<
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CaseLet<State, Action, State1, Action1, Content1>,
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Default<_ExhaustivityCheckView<State, Action>>
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>
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>
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{
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self.init(store) {
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content()
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Default { _ExhaustivityCheckView<State, Action>(file: file, line: line) }
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}
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}
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public init<State1, Action1, Content1, State2, Action2, Content2, DefaultContent>(
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_ store: Store<State, Action>,
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@ViewBuilder content: @escaping () -> TupleView<
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(
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>,
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Default<DefaultContent>
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)
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>
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)
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where
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Content == WithViewStore<
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State,
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Action,
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_ConditionalContent<
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_ConditionalContent<
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>
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>,
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Default<DefaultContent>
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>
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>
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{
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self.init(store: store) {
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let content = content().value
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return WithViewStore(store, removeDuplicates: { enumTag($0) == enumTag($1) }) { viewStore in
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if content.0.toLocalState(viewStore.state) != nil {
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content.0
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} else if content.1.toLocalState(viewStore.state) != nil {
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content.1
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} else {
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content.2
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}
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}
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}
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}
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public init<State1, Action1, Content1, State2, Action2, Content2>(
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_ store: Store<State, Action>,
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file: StaticString = #file,
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line: UInt = #line,
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@ViewBuilder content: @escaping () -> TupleView<
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(
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>
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)
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>
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)
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where
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Content == WithViewStore<
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State,
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Action,
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_ConditionalContent<
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_ConditionalContent<
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>
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>,
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Default<_ExhaustivityCheckView<State, Action>>
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>
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>
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{
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let content = content()
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self.init(store) {
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content.value.0
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content.value.1
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Default { _ExhaustivityCheckView<State, Action>(file: file, line: line) }
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}
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}
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public init<
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State1, Action1, Content1,
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State2, Action2, Content2,
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State3, Action3, Content3,
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DefaultContent
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>(
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_ store: Store<State, Action>,
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@ViewBuilder content: @escaping () -> TupleView<
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(
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>,
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CaseLet<State, Action, State3, Action3, Content3>,
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Default<DefaultContent>
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)
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>
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)
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where
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Content == WithViewStore<
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State,
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Action,
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_ConditionalContent<
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_ConditionalContent<
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>
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>,
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_ConditionalContent<
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CaseLet<State, Action, State3, Action3, Content3>,
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Default<DefaultContent>
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>
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>
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>
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{
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self.init(store: store) {
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let content = content().value
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return WithViewStore(store, removeDuplicates: { enumTag($0) == enumTag($1) }) { viewStore in
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if content.0.toLocalState(viewStore.state) != nil {
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content.0
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} else if content.1.toLocalState(viewStore.state) != nil {
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content.1
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} else if content.2.toLocalState(viewStore.state) != nil {
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content.2
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} else {
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content.3
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}
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}
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}
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}
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public init<State1, Action1, Content1, State2, Action2, Content2, State3, Action3, Content3>(
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_ store: Store<State, Action>,
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file: StaticString = #file,
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line: UInt = #line,
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@ViewBuilder content: @escaping () -> TupleView<
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(
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>,
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CaseLet<State, Action, State3, Action3, Content3>
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)
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>
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)
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where
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Content == WithViewStore<
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State,
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Action,
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_ConditionalContent<
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_ConditionalContent<
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>
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>,
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_ConditionalContent<
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CaseLet<State, Action, State3, Action3, Content3>,
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Default<_ExhaustivityCheckView<State, Action>>
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>
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>
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>
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{
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let content = content()
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self.init(store) {
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content.value.0
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content.value.1
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content.value.2
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Default { _ExhaustivityCheckView<State, Action>(file: file, line: line) }
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}
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}
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public init<
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State1, Action1, Content1,
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State2, Action2, Content2,
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State3, Action3, Content3,
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State4, Action4, Content4,
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DefaultContent
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>(
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_ store: Store<State, Action>,
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@ViewBuilder content: @escaping () -> TupleView<
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(
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>,
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CaseLet<State, Action, State3, Action3, Content3>,
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CaseLet<State, Action, State4, Action4, Content4>,
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Default<DefaultContent>
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)
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>
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)
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where
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Content == WithViewStore<
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State,
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Action,
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_ConditionalContent<
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_ConditionalContent<
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_ConditionalContent<
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>
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>,
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_ConditionalContent<
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CaseLet<State, Action, State3, Action3, Content3>,
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CaseLet<State, Action, State4, Action4, Content4>
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>
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>,
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Default<DefaultContent>
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>
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>
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{
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self.init(store: store) {
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let content = content().value
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return WithViewStore(store, removeDuplicates: { enumTag($0) == enumTag($1) }) { viewStore in
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if content.0.toLocalState(viewStore.state) != nil {
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content.0
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} else if content.1.toLocalState(viewStore.state) != nil {
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content.1
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} else if content.2.toLocalState(viewStore.state) != nil {
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content.2
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} else if content.3.toLocalState(viewStore.state) != nil {
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content.3
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} else {
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content.4
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}
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}
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}
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}
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public init<
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State1, Action1, Content1,
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State2, Action2, Content2,
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State3, Action3, Content3,
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State4, Action4, Content4
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>(
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_ store: Store<State, Action>,
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file: StaticString = #file,
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line: UInt = #line,
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@ViewBuilder content: @escaping () -> TupleView<
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(
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>,
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CaseLet<State, Action, State3, Action3, Content3>,
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CaseLet<State, Action, State4, Action4, Content4>
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)
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>
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)
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where
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Content == WithViewStore<
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State,
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Action,
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_ConditionalContent<
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_ConditionalContent<
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_ConditionalContent<
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>
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>,
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_ConditionalContent<
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CaseLet<State, Action, State3, Action3, Content3>,
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CaseLet<State, Action, State4, Action4, Content4>
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>
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>,
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Default<_ExhaustivityCheckView<State, Action>>
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>
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>
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{
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let content = content()
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self.init(store) {
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content.value.0
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content.value.1
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content.value.2
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content.value.3
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Default { _ExhaustivityCheckView<State, Action>(file: file, line: line) }
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}
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}
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public init<
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State1, Action1, Content1,
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State2, Action2, Content2,
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State3, Action3, Content3,
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State4, Action4, Content4,
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State5, Action5, Content5,
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DefaultContent
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>(
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_ store: Store<State, Action>,
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@ViewBuilder content: @escaping () -> TupleView<
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(
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>,
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CaseLet<State, Action, State3, Action3, Content3>,
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CaseLet<State, Action, State4, Action4, Content4>,
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CaseLet<State, Action, State5, Action5, Content5>,
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Default<DefaultContent>
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)
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>
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)
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where
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Content == WithViewStore<
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State,
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Action,
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_ConditionalContent<
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_ConditionalContent<
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_ConditionalContent<
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>
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>,
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_ConditionalContent<
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CaseLet<State, Action, State3, Action3, Content3>,
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CaseLet<State, Action, State4, Action4, Content4>
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>
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>,
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_ConditionalContent<
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CaseLet<State, Action, State5, Action5, Content5>,
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Default<DefaultContent>
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>
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>
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>
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{
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self.init(store: store) {
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let content = content().value
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return WithViewStore(store, removeDuplicates: { enumTag($0) == enumTag($1) }) { viewStore in
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if content.0.toLocalState(viewStore.state) != nil {
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content.0
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} else if content.1.toLocalState(viewStore.state) != nil {
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content.1
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} else if content.2.toLocalState(viewStore.state) != nil {
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content.2
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} else if content.3.toLocalState(viewStore.state) != nil {
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content.3
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} else if content.4.toLocalState(viewStore.state) != nil {
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content.4
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} else {
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content.5
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}
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}
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}
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}
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public init<
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State1, Action1, Content1,
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State2, Action2, Content2,
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State3, Action3, Content3,
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State4, Action4, Content4,
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State5, Action5, Content5
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>(
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_ store: Store<State, Action>,
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file: StaticString = #file,
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line: UInt = #line,
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@ViewBuilder content: @escaping () -> TupleView<
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(
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>,
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CaseLet<State, Action, State3, Action3, Content3>,
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CaseLet<State, Action, State4, Action4, Content4>,
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CaseLet<State, Action, State5, Action5, Content5>
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)
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>
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)
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|
where
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Content == WithViewStore<
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State,
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Action,
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_ConditionalContent<
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_ConditionalContent<
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_ConditionalContent<
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CaseLet<State, Action, State1, Action1, Content1>,
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CaseLet<State, Action, State2, Action2, Content2>
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>,
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_ConditionalContent<
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CaseLet<State, Action, State3, Action3, Content3>,
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CaseLet<State, Action, State4, Action4, Content4>
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>
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>,
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_ConditionalContent<
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|
CaseLet<State, Action, State5, Action5, Content5>,
|
|
Default<_ExhaustivityCheckView<State, Action>>
|
|
>
|
|
>
|
|
>
|
|
{
|
|
let content = content()
|
|
self.init(store) {
|
|
content.value.0
|
|
content.value.1
|
|
content.value.2
|
|
content.value.3
|
|
content.value.4
|
|
Default { _ExhaustivityCheckView<State, Action>(file: file, line: line) }
|
|
}
|
|
}
|
|
}
|
|
|
|
public struct _ExhaustivityCheckView<State, Action>: View {
|
|
@EnvironmentObject private var store: StoreObservableObject<State, Action>
|
|
let file: StaticString
|
|
let line: UInt
|
|
|
|
public var body: some View {
|
|
#if DEBUG
|
|
let message = """
|
|
Warning: SwitchStore.body@\(self.file):\(self.line)
|
|
|
|
"\(debugCaseOutput(self.store.wrappedValue.state.value))" was encountered by a \
|
|
"SwitchStore" that does not handle this case.
|
|
|
|
Make sure that you exhaustively provide a "CaseLet" view for each case in "\(State.self)", \
|
|
or provide a "Default" view at the end of the "SwitchStore".
|
|
"""
|
|
return VStack(spacing: 17) {
|
|
#if os(macOS)
|
|
Text("⚠️")
|
|
#else
|
|
Image(systemName: "exclamationmark.triangle.fill")
|
|
.font(.largeTitle)
|
|
#endif
|
|
|
|
Text(message)
|
|
}
|
|
.frame(maxWidth: .infinity, maxHeight: .infinity)
|
|
.foregroundColor(.white)
|
|
.padding()
|
|
.background(Color.red.edgesIgnoringSafeArea(.all))
|
|
.onAppear {
|
|
breakpoint(
|
|
"""
|
|
---
|
|
\(message)
|
|
---
|
|
"""
|
|
)
|
|
}
|
|
#else
|
|
EmptyView()
|
|
#endif
|
|
}
|
|
}
|
|
|
|
private class StoreObservableObject<State, Action>: ObservableObject {
|
|
let wrappedValue: Store<State, Action>
|
|
|
|
init(store: Store<State, Action>) {
|
|
self.wrappedValue = store
|
|
}
|
|
}
|
|
|
|
private func enumTag<Case>(_ `case`: Case) -> UInt32? {
|
|
let metadataPtr = unsafeBitCast(type(of: `case`), to: UnsafeRawPointer.self)
|
|
let kind = metadataPtr.load(as: Int.self)
|
|
let isEnumOrOptional = kind == 0x201 || kind == 0x202
|
|
guard isEnumOrOptional else { return nil }
|
|
let vwtPtr = (metadataPtr - MemoryLayout<UnsafeRawPointer>.size).load(as: UnsafeRawPointer.self)
|
|
let vwt = vwtPtr.load(as: EnumValueWitnessTable.self)
|
|
return withUnsafePointer(to: `case`) { vwt.getEnumTag($0, metadataPtr) }
|
|
}
|
|
|
|
private struct EnumValueWitnessTable {
|
|
let f1, f2, f3, f4, f5, f6, f7, f8: UnsafeRawPointer
|
|
let f9, f10: Int
|
|
let f11, f12: UInt32
|
|
let getEnumTag: @convention(c) (UnsafeRawPointer, UnsafeRawPointer) -> UInt32
|
|
let f13, f14: UnsafeRawPointer
|
|
}
|