In article <···················@gaspode.harlqn.co.uk>,
Pekka P. Pirinen <·····@harlequin.co.uk> wrote:
>In article <··········@newsbf02.news.aol.com> ······@aol.com (LMayka) writes:
> from the information-theoretical
> point of view, 0 bits can indicate exactly one value, which for
> SIGNED-BYTE would clearly be the integer 0.
>
>One could make a case for -1/2 as well, but I won't bother.
I don't think (signed-byte 0) makes any sense at all. A signed number of N
bits has 1 bit of sign and N-1 bits of magnitude. So (signed-byte 0) would
have -1 bits of magnitude!
The definition of (signed-byte S) can also be used to show that this is
equivalent to the type NIL, i.e. the empty set. The definition of
(signed-byte S) is the integers in the range [-(2^(S-1)), (2^(S-1))-1];
when S = 0, this is [-(2^-1), (2^-1)-1], or [-1/2, -1/2]. And since there
are no integers in that range, it's the empty set.
--
Barry Margolin
BBN PlaNET Corporation, Cambridge, MA
······@bbnplanet.com
Phone (617) 873-3126 - Fax (617) 873-6351