[Cuis-dev] [Ann] Serialization of BlockClosures

[Juan Vuletich]

Hi Folks,

(below)

On 10/1/2019 1:25 AM, Phil B wrote:
> Juan,
>
> On Mon, Sep 30, 2019 at 11:43 PM Juan Vuletich via Cuis-dev 
> <cuis-dev at lists.cuis.st <mailto:cuis-dev at lists.cuis.st>> wrote:
>
>     Hi Nicolas,
>
>     On 9/30/2019 8:36 PM, Nicolas Cellier via Cuis-dev wrote:
>>     Hi Juan,
>>     Something strikes me.
>>     Isn't this example a pathological case of inheritance? Is Color
>>     really kind of Collection? Wouldn't any object potentially be a
>>     collection of its instances variables in this case?
>
>
> Well that kind of gets to a core issue (in an abstract way... I know, 
> your favorite ;-) in that there is nothing inherent about being a 
> Color that one should reasonably expect it to behave as a collection.  
> Sending #collect: etc. on a Color from an outside object doesn't 
> actually make a lot of sense other than to abuse a leaked 
> implementation detail (i.e. that it's actually implemented as a 
> collection.)
>
>
>     It can be considered a space optimization. Just like Squeak's
>     encoding of RGB in a SmallInteger. Other examples in Cuis packages
>     include Float32Matrix3x3, Float32Vector3, Float64Matrix?x?,
>     Float64Quaternion, Float64Vector?, GPSPosition, All these could
>     use ivars, but dont, and inherit from FloatArray or Float64Array.
>
>
> There are FFI reasons as well. (but that's an implementation detail)
>
>     This makes sense especially on 64 bit images for objects whose
>     parts can be 32bit or shorter immediates, and if we build many
>     instances. In this cases, I think the space saving overwheights
>     the inconvenience of not having real ivars.
>
>
> One could argue (and I am) that whether it was implemented it that way 
> for space savings or other reasons that we shouldn't depend on it 
> being a collection because you could just as easily re-implement it as 
> a direct subclass of Object and it would still make sense.  The fact 
> that it is currently a collection seems irrelevant to being a Color.  
> The fact that it would no longer responded to #collect: and friends 
> wouldn't make it any less a Color... so why encourage/support using 
> these (essentially) leaked methods externally?
>
>     -- 
>     Juan Vuletich
>     www.cuis-smalltalk.org  <http://www.cuis-smalltalk.org>
>     https://github.com/Cuis-Smalltalk/Cuis-Smalltalk-Dev
>     https://github.com/jvuletich
>     https://www.linkedin.com/in/juan-vuletich-75611b3
>     @JuanVuletich
>
>
> Thanks,
> Phil

You are both right. Thanks for raising this issue.

I just pushed to GitHub a new Float32SlotsObject, and made Color 
subclass of it. Color is no longer a Collection, and I hope I didn't 
break too many things... Please take a look, and report any problems.

Cheers,

-- 
Juan Vuletich
www.cuis-smalltalk.org
https://github.com/Cuis-Smalltalk/Cuis-Smalltalk-Dev
https://github.com/jvuletich
https://www.linkedin.com/in/juan-vuletich-75611b3
@JuanVuletich

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