I have a problem with D

[Stefan via Digitalmars-d]

On Tuesday, 28 June 2016 at 04:37:34 UTC, Adam Sansier wrote:
> Hi,
>
> I have designed a class based system that involves 
> self-delegation instead of override.
>
> It is similar to event based programming.
>
> I have defined an event as a container type that holds 
> functions(or possibly delegates, but the desire is to avoid 
> them).
>

Hi Adam,

The easiest way to enforce calling of base class's method is to 
make it final and to offer additional functionality only in an 
optional extra method:

class Base
{
    alias EventMethod = void function(Base _this);
    public Event!EventMethod MyEvents

    final public MyEvent()
    {
        // Go ahead and inform subscribed handlers
        MyEvents(this);
        EventExtras(this);
    }

    protected void EventExtras() {} // empty in the base class

}

class Derived : Base
{
    protected override void EventExtras()
    {
       // This does not need to call super.MyEvent

       // Other work done here.
    }
}

Does this help?