goops and encapsulation

[Klaus Schilling <Klaus.Schilling@home.ivm.de>]

Is there a simple way to disable accessing slots of objects bia
slot-ref and slot-set! from outside the module in which its class
was defined, thus letting access to slots be controlled by methods
defined in the module that also defined the class and exported?

I tried to redefine publically slot-set! and slot-ref in those 
modules to trigger misc errors. This seems to work somehow, but 
maybe it causes more troubles than an interface-implementation-
separation might usually be worth. 

Anyone know a better solution?

Klaus Schilling