There was a listlen?! That solves everything.
In case you're curious:
EDIT: Thanks a whole lot!
EDIT2: Also found argc: $numargs
In case you're curious:
[SELECT ALL] Code:
s = ""
loop i (listlen $arg1) [s = (concat $s (at $arg1 (+ $i 1)))]
EDIT: Thanks a whole lot!
EDIT2: Also found argc: $numargs