Add code examples, and documentation

patterns/decorator/ShapeDecorations/Shapes/Circle.cs

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+#region
+
+using System;
+
+#endregion
+
+namespace ShapeDecorations.Shapes;
+
+public class Circle : IShape
+{
+   public void Draw()
+   {
+      Console.WriteLine("Drawing a circle");
+   }
+}

patterns/decorator/ShapeDecorations/Shapes/Decorators/BlueBorder.cs

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+#region
+
+using System;
+
+#endregion
+
+namespace ShapeDecorations.Shapes.Decorators;
+
+/// <summary>
+///     See the RedColor class for details on the implementation
+/// </summary>
+public class BlueBorder : ShapeDecorator
+{
+   /// <summary>
+   ///     See the RedColor class for details on the implementation
+   /// </summary>
+   public BlueBorder(IShape decorated)
+      : base(decorated) { }
+
+   public override void Draw()
+   {
+      _decorated.Draw();
+      Console.WriteLine("\tWith a blue border");
+   }
+}

patterns/decorator/ShapeDecorations/Shapes/Decorators/HugeSize.cs

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+#region
+
+using System;
+
+#endregion
+
+namespace ShapeDecorations.Shapes.Decorators;
+
+public class HugeSize : ShapeDecorator
+{
+   /// <summary>
+   ///     See the RedColor class for details on the implementation
+   /// </summary>
+   /// <param name="decorated">
+   ///     The IShape (whtether concrete IShape or concrete
+   ///     ShapeDecorator) to be decorated
+   /// </param>
+   public HugeSize(IShape decorated)
+      : base(decorated) { }
+
+   public override void Draw()
+   {
+      _decorated.Draw();
+      Console.WriteLine("\tThat is enourmous in size");
+   }
+}

patterns/decorator/ShapeDecorations/Shapes/Decorators/RedColor.cs

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+#region
+
+using System;
+
+#endregion
+
+namespace ShapeDecorations.Shapes.Decorators;
+
+public class RedColor : ShapeDecorator
+{
+   /// <summary>
+   ///     Public ctor. Calls the base class with the passed IShape, thus decorating
+   ///     it.
+   ///     Implementation is left empty, as the base class does all the work needed.
+   /// </summary>
+   /// <param name="decorated"></param>
+   public RedColor(IShape decorated)
+      : base(decorated) { }
+
+   /// <summary>
+   ///     Performs the actual drawing logic, but first calls the decorated member,
+   ///     adding its own logic afterwards.
+   /// </summary>
+   public override void Draw()
+   {
+      // First calls decorated member
+      _decorated.Draw();
+
+      // Then adds additional drawing logic
+      Console.WriteLine("\tWhich is red in color");
+   }
+}

patterns/decorator/ShapeDecorations/Shapes/Decorators/ShapeDecorator.cs

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+namespace ShapeDecorations.Shapes.Decorators;
+
+public abstract class ShapeDecorator : IShape
+{
+   /// <summary>
+   ///     Maintains a reference to the shape which it decorates
+   ///     this allows implementors to add additional steps to the "drawing" process.
+   ///     Marked "protected" so that inheriting classes have access to it.
+   /// </summary
+   protected IShape _decorated;
+
+   /// <summary>
+   ///     Acceps a reference to any IShape.
+   ///     Since the ShapeDecorator itself IS an IShape, this
+   ///     decorator can also decorate other decorators
+   ///     However, since a ShapeDecorator has to be instantiated with an existing
+   ///     IShape,
+   ///     at some point in the chain of decoration, there must be a concrete shape
+   ///     (specifically, a concrete IShape that was createad without having another
+   ///     IShape passed to it)
+   /// </summary>
+   /// <param name="decorated"></param>
+   public ShapeDecorator(IShape decorated)
+   {
+      _decorated = decorated;
+   }
+
+   /// <summary>
+   ///     Marking this abstract satisfies the implementation of IShape,
+   ///     but forces inheriting classes to implement their own drawing logic
+   /// </summary>
+   public abstract void Draw();
+}

patterns/decorator/ShapeDecorations/Shapes/IShape.cs

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+namespace ShapeDecorations.Shapes;
+
+public interface IShape
+{
+   void Draw();
+}

patterns/decorator/ShapeDecorations/Shapes/Rectangle.cs

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+#region
+
+using System;
+
+#endregion
+
+namespace ShapeDecorations.Shapes;
+
+public class Rectangle : IShape
+{
+   public void Draw()
+   {
+      Console.WriteLine("Drawing a Rectangle");
+   }
+}