Minor Refactoring

README.md

@@ -1157,7 +1157,7 @@ class MockAPIClient: APIClientProtocol {
     var response: Book?
 
     func fetchBook(isbn: String) async throws -> Book {
-        guard let response = response else {
+        guard let response else {
             throw URLError(.unknown)
         }
         return response

Sources/Atoms/Context/AtomContext.swift

@@ -77,7 +77,7 @@ public protocol AtomContext {
     /// ```
     ///
     /// - Parameter atom: An atom that associates the value.
-    func reset<Node: Atom>(_ atom: Node)
+    func reset(_ atom: some Atom)
 }
 
 public extension AtomContext {

Sources/Atoms/Context/AtomTestContext.swift

@@ -167,7 +167,7 @@ public struct AtomTestContext: AtomWatchableContext {
     /// ```
     ///
     /// - Parameter atom: An atom that associates the value.
-    public func reset<Node: Atom>(_ atom: Node) {
+    public func reset(_ atom: some Atom) {
         state.store.reset(atom)
     }
 

Sources/Atoms/Context/AtomTransactionContext.swift

@@ -104,7 +104,7 @@ public struct AtomTransactionContext<Coordinator>: AtomWatchableContext {
     ///
     /// - Parameter atom: An atom that associates the value.
     @inlinable
-    public func reset<Node: Atom>(_ atom: Node) {
+    public func reset(_ atom: some Atom) {
         _store.reset(atom)
     }
 

Sources/Atoms/Context/AtomViewContext.swift

@@ -103,7 +103,7 @@ public struct AtomViewContext: AtomWatchableContext {
     ///
     /// - Parameter atom: An atom that associates the value.
     @inlinable
-    public func reset<Node: Atom>(_ atom: Node) {
+    public func reset(_ atom: some Atom) {
         _store.reset(atom)
     }
 

Sources/Atoms/Core/AtomCache.swift

@@ -1,22 +1,28 @@
 @MainActor
-internal protocol AtomCacheBase {
+internal protocol AtomCacheProtocol: CustomStringConvertible {
+    associatedtype Node: Atom
+
+    var atom: Node { get set }
+    var value: Node.Loader.Value? { get set }
     var shouldKeepAlive: Bool { get }
 
     func reset(with store: StoreContext)
 }
 
-internal struct AtomCache<Node: Atom>: AtomCacheBase, CustomStringConvertible {
+internal extension AtomCacheProtocol {
+    var description: String {
+        value.map { "\($0)" } ?? "nil"
+    }
+}
+
+internal struct AtomCache<Node: Atom>: AtomCacheProtocol {
     var atom: Node
     var value: Node.Loader.Value?
 
     var shouldKeepAlive: Bool {
         Node.shouldKeepAlive
     }
 
-    var description: String {
-        value.map { "\($0)" } ?? "nil"
-    }
-
     func reset(with store: StoreContext) {
         store.reset(atom)
     }

Sources/Atoms/Core/AtomState.swift

@@ -1,9 +1,12 @@
 @MainActor
-internal protocol AtomStateBase {
-    var transaction: Transaction? { get nonmutating set }
+internal protocol AtomStateProtocol: AnyObject {
+    associatedtype Coordinator
+
+    var coordinator: Coordinator { get }
+    var transaction: Transaction? { get set }
 }
 
-internal final class AtomState<Coordinator>: AtomStateBase {
+internal final class AtomState<Coordinator>: AtomStateProtocol {
     let coordinator: Coordinator
     var transaction: Transaction?
 

Sources/Atoms/Core/Loader/AsyncSequenceAtomLoader.swift

@@ -44,7 +44,7 @@ public struct AsyncSequenceAtomLoader<Node: AsyncSequenceAtom>: RefreshableAtomL
     /// and returns a final value.
     public func refresh(context: Context) async -> Value {
         let sequence = context.transaction(atom.sequence)
-        let task = Task { () -> Value in
+        let task = Task {
             var phase = Value.suspending
 
             do {

Sources/Atoms/Core/Loader/ObservableObjectAtomLoader.swift

@@ -24,7 +24,7 @@ public struct ObservableObjectAtomLoader<Node: ObservableObjectAtom>: AtomLoader
     /// Handles updates or cancellation of the passed value.
     public func handle(context: Context, with object: Value) -> Value {
         let cancellable = object.objectWillChange.sink { [weak object] _ in
-            guard let object = object else {
+            guard let object else {
                 return
             }
 

Sources/Atoms/Core/Loader/PublisherAtomLoader.swift

@@ -38,7 +38,7 @@ public struct PublisherAtomLoader<Node: PublisherAtom>: RefreshableAtomLoader {
     /// Refreshes and awaits until the asynchronous is finished and returns a final value.
     public func refresh(context: Context) async -> Value {
         let results = context.transaction(atom.publisher).results
-        let task = Task { () -> Value in
+        let task = Task {
             var phase = Value.suspending
 
             for await result in results {

Sources/Atoms/Core/Overrides.swift

@@ -1,7 +1,7 @@
 @MainActor
 internal struct Overrides {
-    private var _entriesForNode = [AtomKey: AtomOverrideBase]()
-    private var _entriesForType = [AtomTypeKey: AtomOverrideBase]()
+    private var _entriesForNode = [AtomKey: any AtomOverrideProtocol]()
+    private var _entriesForType = [AtomTypeKey: any AtomOverrideProtocol]()
 
     nonisolated init() {}
 
@@ -25,7 +25,7 @@ internal struct Overrides {
         let key = AtomKey(atom)
         let baseOverride = _entriesForNode[key] ?? _entriesForType[key.typeKey]
 
-        guard let baseOverride = baseOverride else {
+        guard let baseOverride else {
             return nil
         }
 
@@ -48,8 +48,12 @@ internal struct Overrides {
 }
 
 @MainActor
-internal protocol AtomOverrideBase {}
+internal protocol AtomOverrideProtocol {
+    associatedtype Node: Atom
 
-internal struct AtomOverride<Node: Atom>: AtomOverrideBase {
+    var value: (Node) -> Node.Loader.Value { get }
+}
+
+internal struct AtomOverride<Node: Atom>: AtomOverrideProtocol {
     let value: (Node) -> Node.Loader.Value
 }

Sources/Atoms/Core/StoreContext.swift

@@ -73,7 +73,7 @@ internal struct StoreContext {
         let store = getStore()
         let key = AtomKey(atom)
         let subscription = Subscription(notifyUpdate: notifyUpdate) { [weak store] in
-            guard let store = store else {
+            guard let store else {
                 return
             }
 
@@ -116,7 +116,7 @@ internal struct StoreContext {
     }
 
     @usableFromInline
-    func reset<Node: Atom>(_ atom: Node) {
+    func reset(_ atom: some Atom) {
         let key = AtomKey(atom)
         let value = getNewValue(of: atom, for: key)
 
@@ -369,7 +369,7 @@ private extension StoreContext {
         store.state.caches[key] = cache
 
         // Do not notify update if the new value and the old value are equivalent.
-        if let oldValue = oldValue, !atom._loader.shouldNotifyUpdate(newValue: value, oldValue: oldValue) {
+        if let oldValue, !atom._loader.shouldNotifyUpdate(newValue: value, oldValue: oldValue) {
             return
         }
 
@@ -379,7 +379,7 @@ private extension StoreContext {
         // Notify value update.
         notifyUpdateToObservers()
 
-        guard let oldValue = oldValue else {
+        guard let oldValue else {
             return
         }
 

Sources/Atoms/Core/StoreState.swift

@@ -1,5 +1,5 @@
 internal struct StoreState {
-    var caches = [AtomKey: AtomCacheBase]()
-    var states = [AtomKey: AtomStateBase]()
+    var caches = [AtomKey: any AtomCacheProtocol]()
+    var states = [AtomKey: any AtomStateProtocol]()
     var subscriptions = [AtomKey: [SubscriptionKey: Subscription]]()
 }

Sources/Atoms/Snapshot.swift

@@ -1,13 +1,13 @@
 /// A snapshot structure that captures specific set of values of atoms and their dependency graph.
 public struct Snapshot: CustomStringConvertible {
     internal let graph: Graph
-    internal let caches: [AtomKey: AtomCacheBase]
+    internal let caches: [AtomKey: any AtomCacheProtocol]
     internal let subscriptions: [AtomKey: [SubscriptionKey: Subscription]]
     private let _restore: @MainActor () -> Void
 
     internal init(
         graph: Graph,
-        caches: [AtomKey: AtomCacheBase],
+        caches: [AtomKey: any AtomCacheProtocol],
         subscriptions: [AtomKey: [SubscriptionKey: Subscription]],
         restore: @MainActor @escaping () -> Void
     ) {

Sources/Atoms/Suspense.swift

@@ -190,7 +190,7 @@ private extension Suspense {
                     return
                 }
 
-                guard let task = task else {
+                guard let task else {
                     phase = .suspending
                     return suspensionTask = nil
                 }

Tests/AtomsTests/AsyncPhaseTests.swift

@@ -102,7 +102,7 @@ final class AsyncPhaseTests: XCTestCase {
     func testFlatMap() {
         XCTContext.runActivity(named: "To suspending") { _ in
             let transformed = phases.map { phase in
-                phase.flatMap { _ -> AsyncPhase<Int, TestError> in
+                phase.flatMap { _ -> AsyncPhase<Int, _> in
                     .suspending
                 }
             }
@@ -132,7 +132,7 @@ final class AsyncPhaseTests: XCTestCase {
 
         XCTContext.runActivity(named: "To failure") { _ in
             let transformed = phases.map { phase in
-                phase.flatMap { _ -> AsyncPhase<Int, TestError> in
+                phase.flatMap { _ -> AsyncPhase<Int, _> in
                     .failure(TestError(value: 1))
                 }
             }
@@ -150,7 +150,7 @@ final class AsyncPhaseTests: XCTestCase {
     func testFlatMapError() {
         XCTContext.runActivity(named: "To suspending") { _ in
             let transformed = phases.map { phase in
-                phase.flatMapError { _ -> AsyncPhase<Int, TestError> in
+                phase.flatMapError { _ -> AsyncPhase<_, TestError> in
                     .suspending
                 }
             }
@@ -166,7 +166,7 @@ final class AsyncPhaseTests: XCTestCase {
 
         XCTContext.runActivity(named: "To success") { _ in
             let transformed = phases.map { phase in
-                phase.flatMapError { _ -> AsyncPhase<Int, TestError> in
+                phase.flatMapError { _ -> AsyncPhase<_, TestError> in
                     .success(1)
                 }
             }
@@ -182,7 +182,7 @@ final class AsyncPhaseTests: XCTestCase {
 
         XCTContext.runActivity(named: "To failure") { _ in
             let transformed = phases.map { phase in
-                phase.flatMapError { _ -> AsyncPhase<Int, URLError> in
+                phase.flatMapError { _ -> AsyncPhase<_, URLError> in
                     .failure(URLError(.badURL))
                 }
             }