Passing Types to functions

In essence, I'm not sure you can, although there might be a way using reflection. However, I thought it might be worth mentioning a few points about your code.

1. When a new type instance is created, the New() method is run for the new type instance. Remember, a BlitzMax function doesn't have a type instance associated with it - you can call functions without a specific instance, for example...

TBall.myFunction()

You wouldn't be able to do that with a method. You'd have to make a new ball, and then call the method with it.

Local tmpBall:TBall = New TBall
tmpBall.myMethod()

2. I see what you are trying to do but I'm not entirely sure it can be done that way, unless you start using reflection. Instead, you may want to add functions to each type to count how many of its own type it can find.

3. Finally, I think it's bad practice to put parentheses "()" after your end keywords. You don't need them.

How about something like this:

Global lstObjects:TList = New TList

Type TBall
	Method New()	'The New() you are attempting to use, is actually a method.
		lstObjects.Addlast(Self)
	EndMethod
	Function CountInList( pList:TList )
		Local i%
		For Local tmpBall:TBall = EachIn pList
			i:+1
		Next
		Return i
	EndFunction
EndType

Type TDrWatson
	Method New()
		lstObjects.Addlast(Self)
	EndMethod
	Function CountInList( pList:TList )
		Local i%
		For Local tmpDrWatson:TDrWatson = EachIn pList
			i:+1
		Next
		Return i
	EndFunction
EndType

New TBall
New TBall
New TDrWatson

Print "Total No. of Objects: "+ lstObjects.Count()	
Print "No. of Balls: " + TBall.CountInList( lstObjects )
Print "No. of Dr Watsons: " + TDrWatson.CountInList( lstObjects )

Hope this helps! :-)