[REBOL] Re: Updates to hof script
From: jan:skibinski:sympatico:ca at: 16-Nov-2002 13:15
Hi Dick,
[reffy--ulrich--net] wrote:
> Hi Jan,
>
> In my language, if adding two integers overflows, then I automatically coerce the result
to a higher type.
So do Smalltalk and Rebol. But all static languages I know of would fail here.
Sometimes in quite a bad way - instead of crashing they would continue
with wrong values. For example, Eiffel relies on a C compiler in its
compile mode (It has also its native interpretive mode, useful during
development - Melting Ice Technology, as they advertise it).
Anyway when C register overflows it returns 0 - or at least that was
a case with GNU compiler many years ago. No access to flags, so this is
what you get.and Eiffel would inherit this problem.
So much for safety and strong typing. See description of example of failure
of Ariadne rocket, as popularized by Meyer.
But that does not mean that Rebol would not fail because it does
a silent coercion to decimals. It will fail at 2 ** 1024. That's astronomical
number and why one would want to go that far? Well the example
of the Ackerman function demonstrates how easy it is to get there.
From the coercive perspective Smalltalk behaves better than Rebol
because it switches from SmallInteger to LargePositiveInteger
or LargeNegativeInteger, internally represented as sequences of bytes.
Bypassing the float - unless you want to cast the numbers to float.
Sky is you limit here, or rather the amount of memory Smalltalk
is entitled to use for storing those huge numbers.
And you must be of course aware of the fact that the bigger
the float gets, the poorer resolution it has - there are tremendous
holes between two closest float numbers. It's all about
logarithmic scales. Some people still do not get it and try to use
floats for computing with money.Think about all those missing
chunks.
Thinking about it now I have to examine the Rebol decimal!
and money! a bit closer. I was assuming floats, but that cannot
be the case in view of the above.
Jan
> My question is more in line with liking your ideas, but wondering how one would include
such
> possibilities in your notation.
None that I know of. You can always declare and force using
