use decimal

Maciej Stachowiak mjs at apple.com
Wed Sep 17 17:05:14 PDT 2008


On Sep 17, 2008, at 4:48 PM, Sam Ruby wrote:

> Maciej Stachowiak wrote:
>> On Sep 17, 2008, at 2:34 PM, Douglas Crockford wrote:
>>> Sam Ruby wrote:
>>>
>>>> To the extent that I understand Doug's proposal, it essentially  
>>>> is an
>>>> opt-in that would remove a feature (binary64 floating points); and
>>>> therefore would likely be about as successful as an opt-in that
>>>> removed another feature that Doug dislikes, such as "with".  Am I
>>>> missing something?
>>>
>>> It would replace a feature that many consider to be broken with a  
>>> feature that
>>> we hope will work better.
>> While decimal floating point may be better than binary floating  
>> point for some applications, such as currency calculations, it  
>> would be unsuitable for other applications such as graphics. Doing  
>> advanced client-side graphics in JavaScript is an increasingly  
>> popular application. For example, see Processing.JS, Algorithmic  
>> Ink, Mozilla's recent image filtering demo, and any of a number of  
>> charting and graphic applications.
>> Using decimal floating point is unacceptable for these kinds of  
>> applications - the performance would not be acceptable. So we  
>> should not go down a path based on the assumption that binary  
>> floating point can be removed.
>
> If we agree that binary64 isn't a "bug" that needs to be removed,  
> wouldn't the simplest solution that could possibly work be separate  
> number and decimal data types that can be freely convertible between  
> each other, and the absolutely most a "use decimal" could possibly  
> mean is that the interpretation of numeric literals is as decimal  
> floating point as opposed to binary floating point?

That approach sounds much better to me than Doug's proposal.

>> I agree with you and Brendan that these issues are better resolved  
>> in Harmony.
>
> At the minimum, I would hope that we should be able to agree on what  
> the issues are.  If they can't be worked in time, so be it.
>
> Doug has put forward the proposal that Harmony seek to "wholly  
> replace the binary representation with the decimal representation".   
> Is that the consensus of the group?

I certainly do not agree with his proposal. Other embers of the group  
may speak for themselves, but it was not my understanding previously  
that anyone wanted to go down such a road.

  - Maciej



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