[computer-go] Tracking Liberties in GnuGo?

[wing at swcp.com]

I have been dabbling with the liberty tracking code
in GnuGo, and I would like to know whether it is
considered state-of-the-art, or simply an example
of solid code. I have found a couple other ways of
tracking the liberties, and I would like to know
whether they are worth pursuing.

Thanks,
Michael Wing