Robert Goldman writes (2009-Jul-09):
(Replying to an older posting,)
I'd rather have us handle slot-unbound on those optional parts of the system instead of stuffing a bunch of NILs in there.
Well, if you do not initialize slots with NIL, how can people know when it's safe to call an accessor?
Checking SLOT-BOUNDP would mean that users have to know about internal implementation issues: the slot names.
In ASDF, it's especially icky because slots tend to have different names than accessors, so you really have to look into the source.
-T.