(if (is x 0) 1 2)
(prn (if (is x 0) 1 2))
print if x==0 then 1 else 2
also, check out the tutorial. despite it being being in .txt (probably for formatting purposes,) it's actually good:
http://ycombinator.com/arc/tut.txt
ken's reference site is also darn handy:
http://arcfn.com/doc/index.html
printf ("%d\n", x == 0 ? 1 : 2); (prn (if (is x 0) 1 2)
-----