Hi Shaping,
Pharo (& Squeak & Cuis) Float subclass BoxedFloat64 maps exactly to
VW's Double. In 64-bit SmallFloat64 maps exactly to SmallDouble. But I
wonder whether there is any issue here. STON would use the print strings
for (PSC) Float / (VW) Double, and so deseerialization on Pharo would
automatically produce the right class. Going in the other direction might
need some help. APF needs support in PSC before one can port, but are
representable as suitably-sized word arrays. There is no support for __float128
anywhere in the VM (e.g. not even in the FFI) on PSC as yet.
On Tue, Nov 6, 2018 at 12:56 AM Shaping <shap...@uurda.org> wrote:
> STON is able to serialise Pharo’s Floats, what do you mean by double ?
>
>
>
> Floating-point numbers in IEEE 64-bit format, 14 or 15 significant digits,
> with a range between =10^307 and 10^307.
>
>
>
> Additionally, I recently asked Sven if t would be possible to store
> ScaledDecimals (I think it implements what you call
> ArbitraryPrecisionFloats) without loss of precision.
>
>
>
> I’m referring VW’s Double (and SmallDouble in 64-bit engines/images).
> APFs are binary representations that can be arbitrarily large, using
> Integers (LargePositiveIntegers for example) to model the bits of the
> mantissa.
>
>
>
> Before, because STON extends JSON, it was storing all kind of numbers
> either as float or integer.
>
>
>
> Now, thanks to Sven, STON stores ScaledDecimals correctly (without loss of
> precision through serialisation as float, what was done before).
>
>
>
> But I do not know if this change is integrated in recent images yet.
>
>
>
> …..
>
>
>
> Number subclass: #Float
>
> instanceVariableNames: ''
>
> classVariableNames: 'E Epsilon Halfpi Infinity Ln10 Ln2
> MaxVal MaxValLn MinValLogBase2 NaN NegativeInfinity NegativeZero Pi
> RadiansPerDegree Sqrt2 ThreePi Twopi'
>
> poolDictionaries: ''
>
> category: 'Kernel-Numbers'
>
>
>
>
>
> My instances represent IEEE-754 floating-point double-precision numbers.
> They have about 16 digits of accuracy and their range is between plus and
> minus 10^307. Some valid examples are:
>
>
>
> 8.0 13.3 0.3 2.5e6 1.27e-30 1.27e-31 -12.987654e12
>
> ….
>
>
>
> I see that Pharo’s Float is VW’s Double. So then I just need to be able
> to serialize APF.
>
>
>
> ….
>
> FIFloatType subclass: #FFIFloat128
>
> instanceVariableNames: ''
>
> classVariableNames: ''
>
> poolDictionaries: ''
>
> category: 'UnifiedFFI-Types'
>
>
>
>
>
> I'm a 128bits (cuadruple precision) float.
>
> It is usually not used, but some compiler modes support it (__float128 in
> gcc)
>
>
>
> THIS IS NOT YET SUPPORTED
>
> ….
>
>
>
> The class above is also from the Pharo 7 image. This is the largest of
> the c-type FFIFloats. Any Float classes of this size and larger for the
> Smalltalk heap on 64-bit Pharo?
>
>
>
>
>
> Cheers,
>
>
>
> Shaping
>
>
>
>
>
> Le 6 nov. 2018 à 06:58, Shaping <shap...@uurda.org> a écrit :
>
>
>
> (Having domain problems recently. Please excuse this posting if you have
> seen it twice. I've not seen it appear yet on the list.)
>
>
> Can STON be extended to handle Doubles and ArbitraryPrecisionFloats?
>
> Shaping
>
> -----Original Message-----
> From: Pharo-dev [mailto:pharo-dev-boun...@lists.pharo.org
> <pharo-dev-boun...@lists.pharo.org>] On Behalf Of
> David T. Lewis
> Sent: Wednesday, October 31, 2018 14:58
> To: Pharo Development List <pharo-dev@lists.pharo.org>
> Subject: Re: [Pharo-dev] [ANN] The STON Specification
>
> This is very clear and well written.
>
> Dave
>
>
> Hi,
>
> Since there can never be enough documentation I finally took some time
> to write a more formal description of STON as a data format.
>
> https://github.com/svenvc/ston/blob/master/ston-spec.md
>
> The idea is to let this stabilise a bit and to then update the two
> other documents describing STON, where necessary:
>
> https://github.com/svenvc/ston/blob/master/ston-paper.md
>
> https://ci.inria.fr/pharo-contribution/job/EnterprisePharoBook/lastSuc
> cessfulBuild/artifact/book-result/STON/STON.html
>
> Also, the latest changes in STON have to make their way to the Pharo
> image as well.
>
> https://github.com/svenvc/ston
>
> All feedback is welcome.
>
> Sven
>
>
> --
> Sven Van Caekenberghe
> Proudly supporting Pharo
> http://pharo.org
> http://association.pharo.org
> http://consortium.pharo.org
>
>
>
>
>
>
>
>
>
>
--
_,,,^..^,,,_
best, Eliot
