using System;

​

abstract class Statement

{

}

class PlainOldCodeStatement : Statement

{

    public virtual void CompileStatement(PlainOldCodeStatement stmt)

    {

        Console.WriteLine("PlainOldCodeStatement called!");

    }

}

class StateDeclarationStatement : Statement

{

    public virtual void CompileStatement(StateDeclarationStatement stmt)

    {

        Console.WriteLine("StateDeclarationStatement called!");

    }

}

class ActorCompiler

{

    public virtual void CompileStatement(Statement stmt)

    {

        Console.WriteLine("Statement called!");

    }

}

​

public class Program

{

    public static void Main()

    {

        Statement stmt = new PlainOldCodeStatement();

        new ActorCompiler().CompileStatement(stmt);

        stmt = new StateDeclarationStatement();

        new ActorCompiler().CompileStatement(stmt);

    }

}