From: "Hal E. Fulton" <hfulton / austin.rr.com>
> Oh, really, don't you think this is a bit much? When
> does it make sense to set an individual digit of a
> large decimal number?

This allows you to simply use a bignum as a very compact array of
booleans.  However is has now become clear that this idea won't work.
We need to develop a nice BitVector type and include it as an
extension.

-Wayne