|fn||function that takes as many arguments as there are lists|
|lists||lists which elements are processed in parallel|
MAPC applies function FN to elements of lists with same index. Each application result forgotten. Elemnts are processed only up to length of the shortest list argument. See MAPCAR, MAPCAN, MAPCON, DOLIST.
(setq dummy nil) => NIL (mapc #'(lambda (&rest x) (setq dummy (append dummy x))) '(1 2 3 4) '(a b c d e) '(x y z)) => (1 2 3 4) dummy => (1 A X 2 B Y 3 C Z)