Implement `DynamicProperty` (#213)

Sources/TokamakCore/App/AppStorage.swift

@@ -17,7 +17,7 @@
 
 import OpenCombine
 
-@propertyWrapper public struct AppStorage<Value>: ObservedProperty {
+@propertyWrapper public struct AppStorage<Value>: DynamicProperty {
   let provider: _StorageProvider?
   @Environment(\._defaultAppStorage) var defaultProvider: _StorageProvider?
   var unwrappedProvider: _StorageProvider {
@@ -51,7 +51,7 @@ import OpenCombine
   }
 }
 
-extension AppStorage: DynamicProperty {}
+extension AppStorage: ObservedProperty {}
 
 extension AppStorage {
   public init(wrappedValue: Value,

Sources/TokamakCore/App/Scenes/SceneStorage.swift

@@ -23,7 +23,7 @@ public enum _DefaultSceneStorageProvider {
   public static var `default`: _StorageProvider!
 }
 
-@propertyWrapper public struct SceneStorage<Value>: ObservedProperty {
+@propertyWrapper public struct SceneStorage<Value>: DynamicProperty {
   let key: String
   let defaultValue: Value
   let store: (_StorageProvider, String, Value) -> ()
@@ -51,6 +51,8 @@ public enum _DefaultSceneStorageProvider {
   }
 }
 
+extension SceneStorage: ObservedProperty {}
+
 extension SceneStorage {
   public init(wrappedValue: Value,
               _ key: String) where Value == Bool {

Sources/TokamakCore/DynamicProperty.swift

@@ -15,5 +15,43 @@
 //  Created by Carson Katri on 7/17/20.
 //
 
-// FIXME: Match SwiftUI implementation
-protocol DynamicProperty {}
+import Runtime
+
+public protocol DynamicProperty {
+  mutating func update()
+}
+
+extension DynamicProperty {
+  public mutating func update() {}
+}
+
+extension TypeInfo {
+  /// Extract all `DynamicProperty` from a type, recursively.
+  /// This is necessary as a `DynamicProperty` can be nested.
+  /// `EnvironmentValues` can also be injected at this point.
+  func dynamicProperties(_ environment: EnvironmentValues,
+                         source: inout Any,
+                         shouldUpdate: Bool) -> [PropertyInfo] {
+    var dynamicProps = [PropertyInfo]()
+    for prop in properties where prop.type is DynamicProperty.Type {
+      dynamicProps.append(prop)
+      // swiftlint:disable force_try
+      let propInfo = try! typeInfo(of: prop.type)
+      propInfo.injectEnvironment(from: environment, into: &source)
+      var extracted = try! prop.get(from: source)
+      dynamicProps.append(
+        contentsOf: propInfo.dynamicProperties(environment,
+                                               source: &extracted,
+                                               shouldUpdate: shouldUpdate)
+      )
+      // swiftlint:disable:next force_cast
+      var extractedDynamicProp = extracted as! DynamicProperty
+      if shouldUpdate {
+        extractedDynamicProp.update()
+      }
+      try! prop.set(value: extractedDynamicProp, on: &source)
+      // swiftlint:enable force_try
+    }
+    return dynamicProps
+  }
+}

Sources/TokamakCore/Environment/Environment.swift

@@ -23,7 +23,7 @@ protocol EnvironmentReader {
   mutating func setContent(from values: EnvironmentValues)
 }
 
-@propertyWrapper public struct Environment<Value>: EnvironmentReader {
+@propertyWrapper public struct Environment<Value>: DynamicProperty {
   enum Content {
     case keyPath(KeyPath<EnvironmentValues, Value>)
     case value(Value)
@@ -50,3 +50,5 @@ protocol EnvironmentReader {
     }
   }
 }
+
+extension Environment: EnvironmentReader {}

Sources/TokamakCore/Environment/EnvironmentObject.swift

@@ -17,8 +17,7 @@
 
 import OpenCombine
 
-@propertyWrapper public struct EnvironmentObject<ObjectType>: ObservedProperty,
-  EnvironmentReader
+@propertyWrapper public struct EnvironmentObject<ObjectType>: DynamicProperty
   where ObjectType: ObservableObject {
   @dynamicMemberLookup public struct Wrapper {
     internal let root: ObjectType
@@ -63,6 +62,8 @@ import OpenCombine
   public init() {}
 }
 
+extension EnvironmentObject: ObservedProperty, EnvironmentReader {}
+
 extension ObservableObject {
   static var environmentStore: WritableKeyPath<EnvironmentValues, Self?> {
     \.[ObjectIdentifier(self)]

Sources/TokamakCore/StackReconciler.swift

@@ -142,11 +142,17 @@ public final class StackReconciler<R: Renderer> {
                  body bodyKeypath: ReferenceWritableKeyPath<MountedCompositeElement<R>, Any>,
                  result: KeyPath<MountedCompositeElement<R>, (Any) -> T>) -> T {
     let info = try! typeInfo(of: compositeElement.elementType)
+    info.injectEnvironment(from: compositeElement.environmentValues,
+                           into: &compositeElement[keyPath: bodyKeypath])
 
     let needsSubscriptions = compositeElement.subscriptions.isEmpty
 
     var stateIdx = 0
-    for property in info.properties {
+    let dynamicProps = info.dynamicProperties(compositeElement.environmentValues,
+                                              source: &compositeElement[keyPath: bodyKeypath],
+                                              shouldUpdate: true)
+    for property in dynamicProps {
+      // Setup state/subscriptions
       if property.type is ValueStorage.Type {
         setupState(id: stateIdx, for: property, of: compositeElement, body: bodyKeypath)
         stateIdx += 1

Sources/TokamakCore/State/Binding.swift

@@ -21,7 +21,7 @@ typealias Updater<T> = (inout T) -> ()
  view's state in-place synchronously, but only schedule an update with
  the renderer at a later time.
  */
-@propertyWrapper public struct Binding<Value> {
+@propertyWrapper public struct Binding<Value>: DynamicProperty {
   public var wrappedValue: Value {
     get { get() }
     nonmutating set { set(newValue) }

Sources/TokamakCore/State/ObservedObject.swift

@@ -22,7 +22,7 @@ protocol ObservedProperty: DynamicProperty {
 }
 
 @propertyWrapper
-public struct ObservedObject<ObjectType>: ObservedProperty where ObjectType: ObservableObject {
+public struct ObservedObject<ObjectType>: DynamicProperty where ObjectType: ObservableObject {
   @dynamicMemberLookup
   public struct Wrapper {
     let root: ObjectType
@@ -52,4 +52,4 @@ public struct ObservedObject<ObjectType>: ObservedProperty where ObjectType: Obs
   }
 }
 
-extension ObservedObject: DynamicProperty {}
+extension ObservedObject: ObservedProperty {}

Sources/TokamakCore/State/State.swift

@@ -14,14 +14,13 @@
 //
 //  Created by Max Desiatov on 08/04/2020.
 //
-
 protocol ValueStorage {
   var getter: (() -> Any)? { get set }
   var setter: ((Any) -> ())? { get set }
   var anyInitialValue: Any { get }
 }
 
-@propertyWrapper public struct State<Value> {
+@propertyWrapper public struct State<Value>: DynamicProperty {
   private let initialValue: Value
 
   var anyInitialValue: Any { initialValue }
@@ -48,7 +47,6 @@ protocol ValueStorage {
 }
 
 extension State: ValueStorage {}
-extension State: DynamicProperty {}
 
 extension State where Value: ExpressibleByNilLiteral {
   @inlinable public init() { self.init(wrappedValue: nil) }