using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("EXAMPLE 1");

        {

            var person = new Person { Name = "Sam", Age = 29 };

            Console.Write("BEFORE: ");

            Console.WriteLine(person);

            var personCopy = person; // Easy because Person is a struct rather than a class.

            Console.Write("AFTER: ");

            Console.WriteLine(personCopy);

        }

        Console.WriteLine("EXAMPLE 2");

        {

            var person = new Person { Name = "Sam", Age = 29 };

            //Console.Write("BEFORE: ");

            //Console.WriteLine(person);

            TestOperationOnPseudoPointer(person);

            //Console.Write("AFTER: ");

            //Console.WriteLine(person);

        }

        Console.WriteLine("EXAMPLE 3");

        {

            var person = new Person { Name = "Sam", Age = 29 };

            Console.Write("BEFORE: ");

            Console.WriteLine(person);

            TestOperationOnCustomPointer(new Pointer<Person>(value => person = value)); // A bit verbose?

            Console.Write("AFTER: ");

            Console.WriteLine(person);

        }

        Console.WriteLine("EXAMPLE 4");

        {

            var person = new Person { Name = "Sam", Age = 29 };

            Console.Write("BEFORE: ");

            Console.WriteLine(person);

            TestOperationOnNonPointer(person);

            Console.Write("AFTER: ");

            Console.WriteLine(person);

        }

    }

    public static void TestOperationOnPseudoPointer(Nullable<Person> person)

    {

        // Can check if my "pointer" is nil with person.HasValue, but no need to do that in this case

        // person.Value is like dereferencing

        //person.Value.Name = "George"; // Does not compile. This prevents side-effects upstream, but we can't modify the value of the underlying the reference.

    }

    public static void TestOperationOnCustomPointer(Pointer<Person> person)

    {

        person.Value.Name = "George";

        person.Value.Age = 27;

    }

    public static void TestOperationOnNonPointer(Person person)

    {

        person.Name = "George";

        person.Age = 27;

    }

    public struct Person

    {

        public string Name;

        public int Age;

    }

​

    public class Pointer<T>

    {

        private readonly Func<T> getter;

        private readonly Action<T> setter;

        public T Value

        {

            get

            {

                if (getter == null)

                {

                    throw new InvalidOperationException();

                }

                return getter();

            }

            set

            {

                if (setter == null)

                {

                    throw new InvalidOperationException();

                }

                setter(value);

            }

        }

​

        private Pointer() {}

        public Pointer(Func<T> getter)

        {

            this.getter = getter;

        }

        public Pointer(Action<T> setter)

        {

            this.setter = setter;

        }

​

        public Pointer(Func<T> getter, Action<T> setter)

        {

            this.getter = getter;

            this.setter = setter;

        }

        public static bool operator ==(Pointer<T> pointer, T value) => pointer.Value == value;

        public static bool operator !=(Pointer<T> pointer, T value) => pointer.Value != value;

        public static bool operator ==(T value, Pointer<T> pointer) => value == pointer.Value;

        public static bool operator !=(T value, Pointer<T> pointer) => value != pointer.Value;

        public static bool operator ==(Pointer<T> pointer1, Pointer<T> pointer2) => pointer1.Value == pointer2.Value;

        public static bool operator !=(Pointer<T> pointer1, Pointer<T> pointer2) => pointer1.Value != pointer2.Value;

        // TODO Override Object.Equals() and Object.GetHashCode()

    }

}

​