generate-accessors and print-instance

[David McKelvie <david%ecrcvax.uucp%germany.csnet@RELAY.CS.NET>]

I'm using PCL on a Xerox 1108 Koto.
When I specify a class with :generate-accessors = nil as in
	(ndefstruct (thing (:class class)(:generate-accessors nil)) a b)
with the intent that I'm never going to access the slots of instances
of this class using methods like (thing-a),
then when I try to create an instance of this class, it fails in
print-instance when it tries to print out the result with 'unspecified
function NIL'.
Clearly, I'm doing something wrong. Does anyone know how to suppress the
creation of the accessor methods properly?