[Caml-list] Creating recursive values

[Jonathan Roewen <jonathan.roewen@gmail.com>]

Hi,

The title might not be quite correct, but I don't really know how to
describe it. Anyways, I'm trying to create a value which references
another value that has to reference the original value.

let make_window origin bounds title =
	let (x,y) = origin
	and (w,h) = bounds in
	let window = GroupedGraphic (
		x, y, [
			InteractiveGraphic (
				[(Up,Graphic (Rectangle (0,0,w+8,h+8), control_brush, control_pen))],
				[(MouseDrag, on_drag)] (* Where trouble begins =( *)
			);
			Graphic (Rectangle (4,4,w,h), white_brush, control_pen);
		]
	)
	and on_drag () = match window with
	| GroupedGraphic (x,y,lst) -> GroupedGraphic (x+mouse.x,y+mouse.y,lst);
	redraw_gui () in
	window

I don't really want to have to deconstruct the window, and reconstruct
it again. I tried to make a start on that, and it was very messy.
There _has_ to be a better way to solve this recursive problem.

Regards,
Jonathan Roewen