This patch is a port of Gerd Moellman's patches from 11 September 2002
regarding structure slots in PCL. The key observation behind the
patch(es) is that structure slots are never unbound, so there's no
point in checking that they are unbound.
Nathan | http://www.cs.rose-hulman.edu/~froydnj/ | Credo ut intelligam
From Man's effeminate slackness it begins. --Paradise Lost