On Saturday 18 December 2004 00:42, chris.danx wrote:
> What is the solution to the following problem?  There are two types of
> object in a scene graph, those that may have children and those may not.
>      A leaf may not have children.

Could you redefine this as "There is one type of node in a scenegraph, which 
has an arbitrary number of children"? Leaf nodes are then nodes with zero 
children.

> I've not programmed in O'Caml for a while and am not yet fully
> comfortable with ocamls object system anyway, so I may be being silly.
> Can anyone shed some light on a solution to this?

Why are you using OO? Can you do what you want with modules and variant types 
more easily?

Cheers,
Jon.