appending(path:) and extrect(from:) with errors

[wanbok]

Hi, this is a noob TCA lover. :)

I try to learn TCA from isowords code.
But, I have struggled with swift-case-paths. isowords's code works, but mine is not.

How do I fix the below code:

import SwiftUI
import CasePaths

struct ContentView: View {
  func test() {
    let a = (\FeatureMain.destination)
      .appending(path: /FeatureMain.Destinations.State.featureA) // Error here `No exact matches in call to instance method 'appending'`
      .extract(from:) // Also Error here `Reference to member 'extract(from:)' cannot be resolved without a contextual type`
  }
  ...
}

import CasePaths

public struct FeatureMain {
  public struct Destinations {
    public enum State: Equatable {
      case featureA(FeatureA.State)
      case featureB(FeatureB.State)
      
      public enum Tag: Int {
        case featureA
        case featureB
      }
      
      var tag: Tag {
        switch self {
        case .featureA:
          return .featureA
        case .featureB:
          return .featureB
        }
      }
    }
    
    public enum Action: Equatable {
      case featureA(FeatureA.Action)
      case featureB(FeatureB.Action)
    }
  }
  
  public var destination: Destinations.State?
}

public struct FeatureA {
  public struct State: Equatable {}
  public enum Action: Equatable {}
}

public struct FeatureB {
  public struct State: Equatable {}
  public enum Action: Equatable {}
}

[tgrapperon]

Hey @wanbok! Appending KeyPath and CasePath is not something built-in with CasePath (yet). You need to include the following OptionalPaths code from isowords in your project.