gistfile1.cs

public class Option<T>
{
    public readonly T Value;
    
    public bool HasValue 
    {
        get {return Value != null;}
        private set {}
    }
    
    public T Get 
    {
        get 
        {
            if(Value == null)
                throw new InvalidOperationException("Value cannot be null when retrieving");
            return Value;
        }
        private set {}
    }

    public Option(T value) 
    {
        Value = value;
    }

    public T GetOrElse(T other)
    {
        if(Value == null) return other;
        return Value;
    }
}