[Q] Accept circular lists where that is useful in #'mapcar*, #'map* and friends.

[Stephen J. Turnbull]

QUERY

Is this standard CL?

N.B. It has potentially severe performance implications, it seems to
me, since every list must be checked for length/circularity before
iterating, whereas in the current implementation this can be checked
as we go, and simply throw the error when discovered.

Aidan Kehoe writes:
 > changeset: 5273:799742b751c8 tag: tip user: Aidan Kehoe
 > <kehoea at parhasard.net> date: Thu Sep 16 20:34:49 2010 +0100 files:
 > lisp/cl-extra.el src/ChangeLog src/fns.c description: Accept
 > circular lists where that is useful in #'mapcar*, #'map* and
 > friends.