detecting uninitialized components of structures.

[Larry Hunter <Hunter@YALE.ARPA>]

I need a copy-structure that also copies components (instead of making
them EQ).  The straightforward way (walk "copy" down the components
of the structures) bombs because some of the components of the source
may not be initialized.  Uninitialized components are all the same
and can just be skipped, of course.  Unfortunately, there is no way
to tell if a component is uninitialized without causing an error,
at least as far as I can tell.   Is there an equivalent to BOUND?
for structure components that I don't know about?  Should there be
one? Is there anything I can do that doesn't need such an animal?

                                            Larry