Your "items from position 1 to the end minus the last 2 items" can actually be achieved in a nicer manner in Arc:
(cut s 1 -2)
(Note that that's using the Anarki negative-end semantics, which PG has said are better; in arc1.tar, that would be (cut s 1 -3). See http://arclanguage.org/item?id=2225)
