nconc

[RWK@fuji.ila.com (Robert W. Kerns)]

    Date: Wed, 10 Oct 90 10:38:52 MDT
    From: riedesel@daneel.den.mmc.com (Billy Joel)

    I'm curious,
    Does anyone know why nconc is implemented using recursion?
    This tends cause our control stack to overflow when we nconc a 
    large number of lists.
    ...
    Comments?

I think you must be running someone else's
implementation of NCONC.  Perhaps some beginner was
playing with your machine and redefined NCONC with
their own?

NCONC (on both 3600 and Ivory systems) does (essentially)
(SETF (CDR (LAST X)) Y).

LAST is iterative in both systems (and is in microcode on
the 3600's).