|I can't see any reason to not simply terminate arc lists with '(). Arc already treats '() as a false value:|
Does arc use nil simply to be more like common lisp?
(define (ar-false? x)
(or (eq? x 'nil) (eq? x '()) (eq? x #f)))
Related: http://www.paulgraham.com/arcll1.html, http://arclanguage.org/item?id=2995, and tangentially http://arclanguage.org/item?id=11505