Here's a fully functional (as in, working) version of the ROBOTS game I wrote in CL that has heavy LOOP abuse (and FORMAT abuse). It would make a great arc exercise for someone :-)
BTW- Collisions of robots causes debris deadly to other robots.
-Conrad Barski
(defun robots ()
(loop named main
with directions = '((q . -65) (w . -64) (e . -63) (a . -1)
(d . 1) (z . 63) (x . 64) (c . 65))
for pos = 544
then (progn (format t "~%qwe/asd/zxc to move, (t)eleport, (l)eave:")
(let* ((c (read))
(d (assoc c directions)))
(cond (d (+ pos (cdr d)))
((eq 't c) (random 1024))
((eq 'l c) (return-from main 'bye))
(t pos))))
for monsters = (loop repeat 10
collect (random 1024))
then (loop for mpos in monsters
collect (if (> (count mpos monsters) 1)
mpos
(cdar (sort (loop for (k . d) in directions
for new-mpos = (+ mpos d)
collect (cons (+ (abs (- (mod new-mpos 64)
(mod pos 64)))
(abs (- (ash new-mpos -6)
(ash pos -6))))
new-mpos))
'<
:key #'car))))
when (loop for mpos in monsters
always (> (count mpos monsters) 1))
return 'player-wins
do (format t
"~%|~{~<|~%|~,65:;~A~>~}|"
(loop for p
below 1024
collect (cond ((member p monsters)
(cond ((= p pos) (return-from main 'player-loses))
((> (count p monsters) 1) #\#)
(t #\A)))
((= p pos)
#\@)
(t
#\ ))))))
