Use actor

.swiftpm/xcode/xcshareddata/xcschemes/Dripper.xcscheme

@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1600"
+   version = "1.7">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES"
+      buildArchitectures = "Automatic">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "Dripper"
+               BuildableName = "Dripper"
+               BlueprintName = "Dripper"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      shouldAutocreateTestPlan = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "DripperTests"
+               BuildableName = "DripperTests"
+               BlueprintName = "DripperTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "Dripper"
+            BuildableName = "Dripper"
+            BlueprintName = "Dripper"
+            ReferencedContainer = "container:">
+         </BuildableReference>
+      </MacroExpansion>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

.swiftpm/xcode/xcshareddata/xcschemes/DripperTests.xcscheme

@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1600"
+   version = "1.7">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES"
+      buildArchitectures = "Automatic">
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      shouldAutocreateTestPlan = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "DripperTests"
+               BuildableName = "DripperTests"
+               BlueprintName = "DripperTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

Examples/Counter/Counter/Counter.swift

@@ -18,14 +18,40 @@ struct Counter: Dripper {
 
     @Observable
     @MainActor
-    final class State: Sendable {
+    final class State: @preconcurrency CustomStringConvertible {
+
+        // MARK: Properties
+
         var counter: Int = .zero
         var text = ""
+
+        @ObservationIgnored private let id: UUID
+
+        // MARK: Computed Properties
+
+        var description: String {
+            "Count: \(counter)"
+        }
+
+        // MARK: Lifecycle
+
+        init(counter: Int = .zero, text: String = "") {
+            let id = UUID()
+            self.id = id
+            self.counter = counter
+            self.text = text
+            os_log("State initialized: \(id)")
+        }
+
+        deinit {
+            os_log("State deinitialized: \(self.id)")
+        }
     }
 
     enum Action {
         case increaseCounter
         case decreaseCounter
+        case setCounter(value: Int)
         case resetCounter
         case randomNumber
     }
@@ -39,14 +65,14 @@ struct Counter: Dripper {
                 state.counter += 1
             case .decreaseCounter:
                 state.counter -= 1
+            case .setCounter(let value):
+                state.counter = value
             case .resetCounter:
                 state.counter = .zero
             case .randomNumber:
                 return .run { pour in
                     let randomNumber = try await randomNumber()
-
-                    pour(.decreaseCounter)
-                    state.counter = randomNumber
+                    pour(.setCounter(value: randomNumber))
                 }
             }
 
@@ -129,12 +155,3 @@ struct CounterView: View {
         }
     )
 }
-
-#Preview {
-    CounterView(
-        station: Station(
-            initialState: Counter.State(),
-            dripper: Counter()
-        )
-    )
-}

Examples/Counter/Counter/CounterApp.swift

@@ -11,13 +11,30 @@ import Dripper
 
 @main
 struct CounterApp: App {
-    private let counterStation = Station(initialState: Counter.State()) {
-        Counter()
-    }
+
+    // MARK: Properties
+
+    @State private var path: [Int] = []
+
+    // MARK: Computed Properties
 
     var body: some Scene {
         WindowGroup {
-            CounterView(station: counterStation)
+            NavigationStack(path: $path) {
+                List {
+                    NavigationLink("1", value: 1)
+                    NavigationLink("2", value: 2)
+                    NavigationLink("3", value: 3)
+                }
+                .navigationTitle("Starting Counter")
+                .navigationDestination(for: Int.self) { number in
+                    CounterView(
+                        station: Station(initialState: Counter.State(counter: number)) {
+                            Counter()
+                        }
+                    )
+                }
+            }
         }
     }
 }

Sources/Dripper/Drip.swift

@@ -7,29 +7,28 @@
 
 import Foundation
 
-public struct Drip<State: ObservableState, Action>: Dripper {
-
-    // MARK: Nested Types
-
-    public typealias Dripping = @MainActor (_ state: State, _ action: Action) -> Effect<Action>?
+public struct Drip<State: StationState, Action>: Dripper {
 
     // MARK: Properties
 
-    @usableFromInline let drip: Dripping
+    @usableFromInline let drip: @MainActor (State, Action) -> Effect<Action>?
 
     // MARK: Lifecycle
 
     @inlinable
-    public init(_ drip: @escaping Dripping) {
+    public init(
+        _ drip: @MainActor @escaping (_ state: State, _ action: Action) -> Effect<Action>
+    ) {
         self.init(internal: drip)
     }
 
+    @inlinable
     public init(_ dripper: some Dripper<State, Action>) {
         self.init(internal: dripper.drip)
     }
 
     @usableFromInline
-    init(internal drip: @escaping Dripping) {
+    init(internal drip: @MainActor @escaping (State, Action) -> Effect<Action>?) {
         self.drip = drip
     }
 

Sources/Dripper/Dripper.swift

@@ -13,7 +13,7 @@ public typealias DripperOf<D: Dripper> = Dripper<D.State, D.Action>
 
 @MainActor
 public protocol Dripper<State, Action>: Sendable {
-    associatedtype State: ObservableState
+    associatedtype State: StationState
     associatedtype Action
     associatedtype Body
 

Sources/Dripper/DripperBuilder.swift

@@ -8,7 +8,7 @@
 import Foundation
 
 @resultBuilder
-public enum DripperBuilder<State: ObservableState, Action> {
+public enum DripperBuilder<State: StationState, Action> {
     @inlinable
     public static func buildBlock<D: Dripper<State, Action>>(_ dripper: D) -> D {
         dripper
@@ -19,8 +19,8 @@ public enum DripperBuilder<State: ObservableState, Action> {
         expression
     }
 
-    @inlinable
     @MainActor
+    @inlinable
     public static func buildExpression(
         _ expression: any Dripper<State, Action>
     ) -> Drip<State, Action> {

Sources/Dripper/Effect.swift

@@ -10,25 +10,21 @@ import OSLog
 
 // MARK: - Effect
 
-public struct Effect<Action> {
-    public typealias Blend = (_ blend: Pour<Action>) async -> Void
-
-    @usableFromInline let blend: Blend
+public struct Effect<Action>: Sendable {
+    @usableFromInline let blend: @Sendable (_ pour: Pour<Action>) async -> Void
 
     @usableFromInline
-    init(blend: @escaping Blend) {
+    init(blend: @Sendable @escaping (_ pour: Pour<Action>) async -> Void) {
         self.blend = blend
     }
 }
 
 // MARK: - Pour
 
-@MainActor
 public struct Pour<Action>: Sendable {
-    let pour: @MainActor @Sendable (Action) -> Void
+    let pour: @Sendable (Action) -> Void
 
-    @usableFromInline
-    init(pour: @escaping @MainActor @Sendable (Action) -> Void) {
+    public init(pour: @Sendable @escaping (Action) -> Void) {
         self.pour = pour
     }
 
@@ -50,7 +46,7 @@ extension Effect {
     // MARK: Static Functions
 
     public static func run(
-        blend: @escaping @MainActor (_ pour: Pour<Action>) async throws -> Void,
+        blend: @MainActor @escaping (_ pour: Pour<Action>) async throws -> Void,
         catch errorHandler: (@MainActor (_ error: any Error, _ pour: Pour<Action>) async -> Void)? = nil,
         fileID: StaticString = #fileID,
         line: UInt = #line