Now, what I'm sure the other folks in this forum will agree with me on, is what does this FAS code do? Answer that and then decide how to write your own code which will do the same task. It's not that difficult to recreate what a LISP program does, if you just describe what it does to yourself. If contacting the original author is not possible then this is really your best shot at it.
+1 ... that would be your safest bet.
Knowledge is proportional to experience, but wisdom is inversely proportional to ego!
My little bit of "wisdom": Hind-sight is useless, unless used to improve the next forethought!