Re: Motion P1788/M007.01_NaI: NO, several NaIs please
On Tue, Sep 1, 2009 at 9:09 AM, Vincent Lefevre<vincent@xxxxxxxxxx> wrote:
> I also vote NO (I currently don't see the need for NaI's).
>
> On 2009-09-01 05:19:06 -0700, Dan Zuras Intervals wrote:
>> John is quite correct & it is this last that is my meaning.
>>
>> NaNs in 754 have been 'historically useless' (IHMO) precisely
>> BECAUSE we could not settle on a common behavior across
>> platforms. No common behavior. No common code written.
>> No utility for NaNs. (Well, beyond their function as a
>> placeholder for undefined results.)
>
> I don't think this is the reason. You would also need language support
> and bindings. Without language support, such different NaNs would be
> useless. Even the two kinds of NaN's (qNaN and sNaN) are hardly
> supported by C. I don't think this is much better in most other
> languages. Also, IEEE 754-1985 would have had to cover other functions
> than the arithmetic operations and the square root (even if correct
> rounding were not provided), to define their behavior on special
> values (there's a similar problem for pow(0,0)).
And the issue is even much more obscure for some (typed) computer
algebra systems (such as the AXIOM family) to implement correctly.
Insisting on NaI forces other programming languages to forgo language
constructs for handling exceptional situations for a poor-style coding.
I think it is too early to decide whether we really do need NaI.
Consequently, my vote is NO (no NaI at all at this stage.)
-- Gaby