2 Questions: Do I need an interface & C++ -> D code part, how?

[Benjamin Schulte]

Hi,

I've got two questions about D - all containing those class structure:

class Event
{
  this( ) { ... } /// Add event to eventlist
  ~this( ) { ... } /// Remove event from eventlist

  abstract Event[] getEventList( );
}

class MainLoopEvent : Event
{
  abstract void onMainLoop( );

  Event[] getEventList( ) { return events; }
  MainLoopEvent[] events;
}

-----

now my first question:
I've got another class, called MyApplication - I want to have class Application as base class and MainLoopEvent as 2nd base class. So I wrote:

class MyApplication : Application, MainLoopEvent { }

But I got an error, that MainLoopEvent has to be an interface. Is there now another way than saying:

interface EventInterface
{
  // EMPTY!!!
}

class Event : EventInterface
...

Would be nice if I don't have to create an empty interface, just to make D  happy.


---------------
2nd question:

MainLoopEvent has the method onMainLoop( );
Say we create a second class with Event as Base class

class AnotherEvent : Event
{
  abstract void onBeingHappy( int a, int b );
}

Now, now I need a new function. In C++ I could write a macro: (I mixed C++ with D to show you what I mean:)

#define callEvent(classType,event) foreach(Event e; event.getEventList() ) ((classType*)e)

I could now just call
callEvent(MainLoopEvent, myApplication)->onMainLoop( );
callEvent(AnotherEvent, myEvent)->onBeingHappy( 12, 31 );

At the moment my solution for MainLoopEvent looks like this:
	static void callMainLoop( )
	{
		// Call main loop event
		foreach( MainLoopEvent e; events ) e.onMainLoop( );
	}

But that's not my favorite way to do this, because I would have to rewrite this for every abstract method.

Might have some bugs in here, but I hope you understand what I mean. A template that calls methods I don't really know from the structure.




Thanks for every help : )