Re: EQ(UAL) in SUBST

[Guy.Steele at CMU-10A]

I think we've needed such a "halfway" euality function for years,
and it crops up now and again.  So how about it, guys?  I'd be
inclined to call it EQL (more general than EQ, less general than EQUAL
(for a funny sense of "general")).  However, InterLISP has had such
a function for a while and called it EQP.  Whatever we call it,
it should be like EQUAL on non-composite objects and like EQ on
composite ones (I say "non-composite" rather than "atomic" because
there is a question as to whether a vector or array is an atom for
this purpose; I suggest that EQ be used on lists, vectors, arrays,
etc.).

Regarding SUBST: should SUBST traverse vectors and the like?