sperber at informatik.uni-tuebingen.de
Wed Aug 30 11:32:47 EDT 2006
William D Clinger <will at ccs.neu.edu> writes:
> I believe Kent was pointing out that the read procedure
> cannot rely on string->number to *parse* numbers. The
> read procedure must perform its own parsing to separate
> lexically correct external representations for numbers
> from incorrect, and from correct representations of other
I still don't understand. Why is it not correct for `read' to always
raise an exception if string->number returns #f?
> Is string->number allowed to raise an exception?
That, I believe, is consistent with Kent's implementation choice,
which I also prefer.
> In the current draft of the R6RS, however, (/ 0 0#) is given as an
> example whose result could be an exact 0 or +nan.0.
> In my opinion, the exact 0 result is just plain wrong
> That, of course, is just my opinion, based on my
> personal opinion that an exact 0 is not the correct
> result of (/ 0 0). On the other hand, some of the
> other editors evidently regard 0 as the correct result
> of (/ 0 0), which is why the example is as it is in
> the current draft of the R6RS.
Is there explicit evidence or did it just get stuck in the document
and then overlooked? (It sure got overlooked by me.)
> I had raised this issue before, to no good result (pardon the pun),
> so I had put it on my list of issues to be raised during the period
> of public review and comment. If we could correct this example
> before the first public draft, I would be delighted.
Cheers =8-} Mike
Friede, Völkerverständigung und überhaupt blabla
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