LAST

[RWK at MIT-MC (Robert W. Kerns)]

Your comment would be almost valid, except that LAST obviously isn't
just CDR'ing down the list checking for NIL.  It is doing a LIST-P
on the CDR instead.  After all, this isn't very expensive, a MOVEI, a LSH,
and a SKIPL will do it.  I would muchly appreciate it if APPEND would
be changed to do likewise.  (There should also be a TYPEP before the loop,
so (LAST 3.3) wouldn't die).  After all, the interpreter isn't supposed to
be fast, it's supposed to be suportive and not die on easy mistakes.