i don't quite agree with this.
if something is "undefined" as in the prelude, i should be able to prove that this is the case
-- bottom is just another value, admitedly not a very nice one :-)
on the other hand, if something is undefined in the specification
(i.e. implementer can do whatever), than i cannot prove anything about that part of the program.
in particular i cannot prove that it is bottom.
i agree that this is a highly undesirable thing to have in a specification, but haskell
is much better in that respect that most languages out there.
-iavor
Joe Fasel wrote:
On 2004.01.21 15:03, Iavor S. Diatchki wrote:
hi,
not that it matters, but i think commonly when specifications say
that something is undefined, that means that the behaviour can be whatever,
i.e. the implementors can do what they like. this is not to be confused
with the entity "undefined" defined in the Prelude.
-iavor
Well, except that denotationally, they are the same.
--Joe
Joseph H. Fasel, Ph.D. email: [EMAIL PROTECTED]
Systems Planning and Analysis phone: +1 505 667 7158
University of California fax: +1 505 667 2960
Los Alamos National Laboratory post: D-2 MS F609; Los Alamos, NM 87545
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| Iavor S. Diatchki, Ph.D. student | | Department of Computer Science and Engineering |
| School of OGI at OHSU |
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