Some cleanup and documentation. PlotElement rects are now calculated on-the-fly as they drawn, allowing us to omit storing them.

Author: karwa

Sources/SwiftPlot/CopyOnWriteValue.swift

@@ -7,39 +7,58 @@ public protocol Copyable {
 @dynamicMemberLookup
 public protocol _CopyOnWriteValue {
   associatedtype _COWStorage: AnyObject, Copyable
-  var _storage: _COWStorage { get set }
 }
+internal protocol _COWHider {
+    var _storage: AnyObject { get set }
+}
+typealias CopyOnWriteValue = _CopyOnWriteValue & _COWHider
 
 extension _CopyOnWriteValue {
-  public subscript<T>(dynamicMember keypath: KeyPath<_COWStorage, T>) -> T {
-    get { _storage[keyPath: keypath] }
-  }
-  public subscript<T>(dynamicMember keypath: ReferenceWritableKeyPath<_COWStorage, T>) -> T {
-    get { _storage[keyPath: keypath] }
-    _modify {
-      if !isKnownUniquelyReferenced(&_storage) { _storage = _storage.copy() }
-      yield &_storage[keyPath: keypath]
+
+    private var _storage: _COWStorage {
+        get {
+            ((self as! _COWHider)._storage as? _COWStorage).unsafelyUnwrapped
+        }
+        _modify {
+            var c = (self as! _COWHider)._storage as! _COWStorage
+            yield &c
+        }
+        set {
+            var c = (self as! _COWHider)
+            c._storage = newValue
+            self = c as! Self
+        }
     }
-    set {
-      if !isKnownUniquelyReferenced(&_storage) { _storage = _storage.copy() }
-      _storage[keyPath: keypath] = newValue
+    
+    public subscript<T>(dynamicMember keypath: KeyPath<_COWStorage, T>) -> T {
+        get { _storage[keyPath: keypath] }
+    }
+    
+    public subscript<T>(dynamicMember keypath: ReferenceWritableKeyPath<_COWStorage, T>) -> T {
+        get { _storage[keyPath: keypath] }
+        _modify {
+            if !isKnownUniquelyReferenced(&_storage) { _storage = _storage.copy() }
+            yield &_storage[keyPath: keypath]
+        }
+        set {
+            if !isKnownUniquelyReferenced(&_storage) { _storage = _storage.copy() }
+            _storage[keyPath: keypath] = newValue
+        }
     }
-  }
 }
 
-public struct TestObj: _CopyOnWriteValue {
-  
-  public final class _COWStorage: Copyable {
-    public var propOne: Int
-    public var propTwo: String
-    public func copy() -> Self {
-      print("copying")
-      return Self(propOne, propTwo)
+public struct TestObj: CopyOnWriteValue {
+    public final class _COWStorage: Copyable {
+        public var propOne: Int
+        public var propTwo: String
+        public func copy() -> Self {
+            print("copying")
+            return Self(propOne, propTwo)
+        }
+        
+        init(_ p1: Int, _ p2: String) { self.propOne = p1; self.propTwo = p2 }
     }
-    
-    init(_ p1: Int, _ p2: String) { self.propOne = p1; self.propTwo = p2 }
-  }
-  public var _storage = _COWStorage(0, "")
+	var _storage: AnyObject = _COWStorage(0, "")
 
   public init() {}
 }