Re: Motion 46: finalise interval literals, amendments
On 2013-06-23 22:21:08 +0200, Jürgen Wolff von Gudenberg wrote:
> Am 21.06.2013 16:02, schrieb John Pryce:
> >(1) Do we need functions like those suggested by Ian M?
> I tend to NO
Ditto.
> >(2) Should the notation for Empty and Entire be changed to have
> >brackets round, e.g. [empty], as in Sun? (Yes, IMO.)
> YES
I don't mind. I think that Empty and Entire are clear in P1788,
with no ambiguities at all (this is just notation for the standard
itself, not for implementations...). But the brackets could help
if the same notation is used in another context.
> >(3) Should nums2interval() use (as it does currently) the Siegfried
> >Rump scheme where nums2interval(oo,oo) gives [HUGEPOS,oo]?
NO!
> I dare to say yes although the consequences will be
> -- constructor([oo,oo] =[realmax,oo]
> or constructor ([oo,oo]) is invalid
> -- nums2intval [oo] = union of {[a,oo] :a > realmax}
>
> either there is a difference between constructor and num2intval
> or [oo] is a valid interval hence motion 3 is violated.
> ==> I change my yes into NO
What's the difference between "nums2interval" and "constructor"?
Note that nums2interval(+oo,+oo) should never occur in practice,
as RNDD(any real number) < +oo. Or does anyone have an example?
If the goal is to be able to construct [HUGEPOS,+oo], there should
be another way.
> >(4) Should we use Sun's simpler version of "uncertain numbers",
> >instead of the current one, which comes from the Vienna proposal?
> >See <1> in code example below.
If you mean that 1.7 and 1.700 have two different meanings (contrary
to math notation), I don't think this is a good idea: too confusing.
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Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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