Re: Conditional types?

["AG" <ang@xtra.co.nz>]

"Dennis Lee Bieber" <wlfraed@ix.netcom.com> wrote in message
news:emomqa.0d4.ln@beastie.ix.netcom.com...

>         0x80 (just to keep the numbers small) could be signed -128,
unsigned
> +123 -- without some additional information the bit pattern tells one
> nothing.

However, that number can't be the result (assuming 8-bit signed numbers)
of something like:  X := -Y  *if* you know that all possible Y values are
positive. So, if inside a large body of data you find a single pattern like
that, it must mean that one of the assumptions was incorrect: either the
Ys can be negative (and, on top, the negation works like that) or the
operation performed was something different from the simple negation.
Or, maybe, the Ys encoding was different. All of that is info - eliminating
the possibilities. All derived from a single 8-bit pattern too [Well, that
last one isn't really true of course since it did involve quite a bit of
extra
info, but that single 8-bit pattern was the test that allowed to make
a choice between theories about what the data and it's handling are].

>
>         You /might/ be able to identify that /some/ patterns are not
/valid/
> floats, but that is the limit.