Re: Motion P1788/M0006.04_Level_2_Multi-format NO
On 2009-09-07 16:22:08 +0200, Frédéric Goualard wrote:
> Indeed. Anyway, I wonder how such an undefined behavior would be handled
> practically by programming languages that lack exception facilities.
> External flags (such as the infamous C errno) do not seem that good an
> option. Should we really put this burden on implementors (the Standard
> being language agnostic) while identifying [-oo,-oo] and [+oo, +oo] to
> the empty set appears to have so few drawbacks (correct me on that one:
> I have seen many discussions in the Motion 7 thread on that topic and
> may have overlooked some definitive argument against it)?
Perhaps, but the question of whether [-oo,-oo] and [+oo,+oo] should
be left undefined behavior (e.g. because non consensus is reached)
or regarded as some well-defined data (e.g. the empty set or a NaI)
could be discussed later. Also this is IMHO more a representation
issue (Level 3), while Motion 6 is only about Levels 1 and 2.
BTW, I see this as an error (or some ambiguity) in the position paper,
which seems to talk about Level-3 issues in a Level-1 section.
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.org/>
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Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)