[Ecls-list] Re: Decimal Numbers

[GP lisper]

On Wed, 17 Aug 2005 07:14:07 -0400, <marcoxa at cs.nyu.edu> wrote:
>
> On Aug 17, 2005, at 3:18 AM, GP lisper wrote:
>
>> Does someone have a quick guessimate about:
>>
>> A)  Adding the Decimal Number type into ECL
>
> This is a useful enterprise only if the final aim is to provide a 
> portable package, that can be used on all implementations.

Well, maybe not.  It would attract people to ECL when they needed
decimal numbers.  I primarily use CMUCL, when I thought about this my
first choice was 'slisp', then ECL.  Changes such as the above need a
simple place to grow, CMUCL is too big and not easy to hack.  Solving
it for ECL and then letting it spread to other lisps is an easier
approach.


>> B)  Replacing floats with Decimal Numbers.
>
> You got to be kidding! :)

Nope.  For someone as clueless as me, floats would provide a roadmap
to where changes need to be made.  The change would trade speed for
accuracy, some people think that is an excellent tradeoff.  The
Decimal Number package has enough numeric range for most users
(exponents to 999).

My primary use of Common Lisp is for money related programs, floats
are giving ~<1% errors.  There is a recurring thread on c.l.l about
those errors.


But I was really looking for an estimate of effort, I know it's not
simple, but I wonder if it is within my reach...


-- 
On a cloudy day,
You hear the cons cells whisper:
"We are lost and gone."  -- Oliver