gistfile1.txt

import SwiftUI

final class Store<Value, Action>: ObservableObject {
    let reducer: (inout Value, Action) -> Void
    @Published private(set) var value: Value
    
    init(initialValue: Value, reducer: @escaping (inout Value, Action) -> Void) {
        self.reducer = reducer
        self.value = initialValue
    }
    
    func send(_ action: Action) {
        self.reducer(&self.value, action)
    }

}

extension Store {
  public func send<LocalValue>(
    _ action: @escaping (LocalValue) -> Action,
    binding keyPath: KeyPath<Value, LocalValue>
  ) -> Binding<LocalValue> {
    Binding(
      get: { self.value[keyPath: keyPath] },
      set: { self.send(action($0)) }
    )
  }
}

struct AppState {
    var pickerVal = "picker"
    var textVal = "picker"
    
}
enum AppAction {
    case updatePickerVal(String)
    case updateTextVal(String)
}

func reducer(state: inout AppState, action: AppAction) {
    switch action {
    case let .updatePickerVal(val): state.pickerVal = val
    case let .updateTextVal(val): state.textVal = val
    }
    
    print(state)
}

let store: Store<AppState, AppAction> = Store(initialValue: AppState(), reducer: reducer)

struct Test: View {
        
    var body: some View {
        HStack {
            Picker.init(selection: store.send({ .updatePickerVal($0) }, binding: \.pickerVal), label: Text("pick: ")) {
                Text("bar").tag(1)
                Text("baz").tag(2)
            }
            TextField("type: ", text: store.send({ .updateTextVal($0) }, binding: \.textVal))
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View { Test() }
}