Experimenting with bindings

Sources/YadUI/Views/ContainerView.swift

@@ -10,59 +10,55 @@ import Combine
 
 open class ContainerView: UIView {
     
-    private var body: UIView = UIView()
     public var cancellables: [AnyCancellable] = []
+}
 
-    public override init(frame: CGRect) {
-        super.init(frame: frame)
+class BindingModel {
     
-        translatesAutoresizingMaskIntoConstraints = false
+    var srcTag: Int
+    var dstTag: Int
+    var bind: (ContainerView, Int, Int) -> Void
     
-        body = getBody()
-        body.translatesAutoresizingMaskIntoConstraints = false
-        addSubview(body)
-        body.pin(to: self)
-    }
-    
-    required public init?(coder: NSCoder) {
-        fatalError("init(coder:) has not been implemented")
-    }
-    
-    @RootViewBuilder open func getBody() -> UIView {
-        UIView()
+    init(srcTag: Int, dstTag: Int, bind: @escaping (ContainerView, Int, Int) -> Void) {
+        self.srcTag = srcTag
+        self.dstTag = dstTag
+        self.bind = bind
     }
 }
 
 extension UIView {
     
-    private func findContainer() -> ContainerView? {
- 
-        var currentView: UIView = self
-        while currentView.superview != nil {
-            if currentView is ContainerView {
-                return currentView as? ContainerView
-            }
-            currentView = currentView.superview!
-        }
-        
-        return nil
+    private struct AssociatedKeys {
+        static var bindings: Int = 0
     }
     
-    public func bind<Src, SrcView, Dst, DstView>(_ prop: ReferenceWritableKeyPath<SrcView,Src>,
-                                                 to dstTag: Int,
-                                                 dstProp: KeyPath<DstView,Published<Dst>.Publisher>) -> Self where SrcView: UIView, Src: InitConvertible, Src.Param == Dst {
-        
-        guard let container = findContainer(), let srcView = self as? SrcView else {
-            return self
+    var bindings: [BindingModel] {
+        get {
+            objc_getAssociatedObject(self, &AssociatedKeys.bindings) as? [BindingModel] ?? []
         }
-        
-        guard let view = container.viewWithTag(dstTag) as? DstView else {
-            return self
+        set {
+            objc_setAssociatedObject(self,
+                                     &AssociatedKeys.bindings,
+                                     newValue,
+                                     objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
         }
+    }
     
-        let pub = view[keyPath: dstProp].map { Src($0) }
-        pub.assign(to: prop, on: srcView)
-            .store(in: &container.cancellables)
+    public func bind<Src, SrcView, Dst, DstView>(_ dstProp: ReferenceWritableKeyPath<DstView,Dst>,
+                                                 to srcTag: Int,
+                                                 srcProp: KeyPath<SrcView,Published<Src>.Publisher>) -> Self where DstView: UIView, Dst: InitConvertible, Dst.Param == Src {
+        
+        bindings.append(.init(srcTag: srcTag, dstTag: tag, bind: { container, srcTag, dstTag in
+            guard let srcView = container.viewWithTag(srcTag) as? SrcView,
+                  let dstView = container.viewWithTag(dstTag) as? DstView
+            else {
+                return
+            }
+            
+            let publisher = srcView[keyPath: srcProp].map { Dst($0) }
+            publisher.assign(to: dstProp, on: dstView)
+                .store(in: &container.cancellables)
+        }))
                 
         return self
     }

Sources/YadUI/Views/Stack/Stack.swift

@@ -8,8 +8,7 @@
 import UIKit
 import Combine
 
-@available(iOS 13.0, *)
-public class Stack: UIView {
+public class Stack: ContainerView {
     
     public var arrangedSubviews: [UIView]
     public var distribution: Distribution

Sources/YadUI/YadUI.swift

@@ -3,8 +3,8 @@ import UIKit
 @resultBuilder
 public struct RootViewBuilder {
     
-    public static func buildBlock(_ components: UIView...) -> UIView {
-        let view = components.first ?? UIView()
+    public static func buildBlock(_ components: ContainerView...) -> ContainerView {
+        let view = components.first ?? ContainerView()
         return view.withoutAutoresizing()
     }
 }

YadUIDemo/YadUIDemo/ViewController.swift

@@ -22,19 +22,17 @@ extension Stack.Alignment: InitConvertible {
 
 class ViewController: UIViewController {
     
-    let child = TestView()
+    var child = UIView()
 
     override func viewDidLoad() {
         super.viewDidLoad()
         
+        child = buildView()
         view.addSubview(child)
         child.pin(toSafeArea: view, insets: .init(all: 16))
     }
-}
     
-class TestView: ContainerView {
-    
-    override func getBody() -> UIView {
+    @RootViewBuilder func buildView() -> ContainerView {
         VStack(alignment: .start, spacing: 16) {
             UILabel()
                 .text("qwe")
@@ -49,7 +47,7 @@ class TestView: ContainerView {
             YASegmentedControl(items: ["Left", "Center", "Right"])
                 .tag(100)
         }
-        .bind(\VStack.alignment, to: 100, dstProp: \YASegmentedControl.$selectedIndex)
+        .bind(\VStack.alignment, to: 100, srcProp: \YASegmentedControl.$selectedIndex)
     }
 }