[Cuis-dev] [Poll] Re: Uniqueness of Characters (Related to NeoCSV)

[Joseph Turco]

Are pre spur images for older VMs? Maybe this is useful to hang onto for
people with older hardware they still might use, as I see there is somewhat
of a "renaissance" of people using older hardware as life has gotten more
expensive for people all over the world. Just my 2 cents.

Regards,

Joseph Turco

On Mon, Jul 24, 2023, 8:03 AM Juan Vuletich via Cuis-dev <
cuis-dev at lists.cuis.st> wrote:

> Hi Folks,
>
> Dave, do you still need or prefer using V3 images? Anyone else?
>
> Today, in Spur images, UnicodeCodePoints are immediate. And Since
> Smalltalk-80 (and in all Cuis versions), Characters are "quasi immediate":
> they are unique and never allocated once the CharacterTable is built. So,
> only the pointer matters.
>
> Unifying Character and UnicodeCodePoint in a single class would mean that
> we would no longer be able to have ASCII-only images, Unicode would be
> included in any image.
>
> Supporting only Spur images could simplify a few details. It is not a big
> deal, though. Truth is that if we chose to use only UnicodeCodePoint
> (perhaps renaming it 'Character'), then all characters would be immediate
> in Spur. And we can also keep the first 256 code points in a class var, as
> we do with Character, to make them unique also in V3. The downside would be
> that (only in V3 images) codepoints after 256 would not be unique. I gave
> this some thought, and found that this can also be 'fixed'. But is there a
> need for characters to be unique?
>
> I guess the questions are:
>
> - Would there be any real advantage in unifying Character and
> UnicodeCodePoint?
> - Would we gain something valuable if we make all character like objects
> immediate in Spur?
> - Would we gain something valuable if we make all character like objects
> unique?
> - Would we get a real advantage by dropping support for V3 images?
>
> If none of the answers turns out to be a clear YES, the should we bother?
>
> Please share your thoughts. Maybe we can make a thoughtful decision and
> settle this at least for some time.
>
> Thanks!
>
> On 7/24/2023 7:46 AM, Luciano Notarfrancesco via Cuis-dev wrote:
>
> Yes, I agree that independently of what we do about the bigger issue of
> uniqueness of characters, we should replace sends of #== with #= in most
> cases.
> Having immediate characters for both ascii and unicode would be nice, tho.
> Are there good reasons to continue supporting V3 images?
>
> On Mon, 24 Jul 2023 at 04:39 Hernán Wilkinson via Cuis-dev <
> cuis-dev at lists.cuis.st> wrote:
>
>> I think we should keep it the way it is right now and fix the problems
>> when they arise.
>> The message #== should only be used when doing meta-programming of memory
>> stuff related, if not, #= is the right one to use.
>> There is a lot of old code that uses #== instead of #=, most of it due to
>> "performance" reasons, other due to "ignorance", (new smalltalkers confuse
>> == with equality because Java/C#/etc use #== as equality (or message
>> equals) and #= as assignment, etc.
>>  The truth is that, currently, the impact on performance is negligible
>> (performance problems are not due to use #= instead of #==). Using #==
>> instead of #= because a possible performance issue is an early optimization
>> and we all know that "early optimization is the root of all evil" :-)
>>
>> Cheers!
>> Hernan.
>>
>> On Sun, Jul 23, 2023 at 5:05 PM Juan Vuletich <juan at cuis.st> wrote:
>>
>>> Hi Folks,
>>>
>>> Hilaire had trouble, that he already solved, when updating NeoCSV for
>>> current Cuis. The root of the problem is that in older Cuis and in
>>> Smalltalk-80 and Squeak `aCharacter == $,` is guaranteed to mean the
>>> same as `aCharacter = $,`. In other words, there can exist only one
>>> instance of any Character. This is no longer in true today in Cuis: `$,
>>> == $, asUnicodeCodePoint` is false.
>>>
>>> In Cuis we have two character like classes. They are polymorphic, and
>>> the only observable difference is when asking #== or #identityHash.
>>>
>>> The question I ask is: How important is this? Do we need or want
>>> uniqueness of characters? What do other dialects do? Would it make sense
>>> to give an error or at least a warning when trying to compare with #==
>>> against a literal character?
>>>
>>> It is possible to guarantee uniqueness of characters, but not without
>>> some work. The easiest way is what Squeak did, having a single, Unicode
>>> wide, immediate Character class. But this can not be done in pre-Spur
>>> (V3) images and VMs.
>>>
>>> Thanks,
>>>
>>> --
>>> Juan Vuletich
>>> cuis.st
>>> github.com/jvuletich
>>> researchgate.net/profile/Juan-Vuletich
>>> independent.academia.edu/JuanVuletich
>>> patents.justia.com/inventor/juan-manuel-vuletich
>>> linkedin.com/in/juan-vuletich-75611b3
>>> twitter.com/JuanVuletich
>>>
>>>
>>
>> --
>>
>> *Hernán Wilkinson Agile Software Development, Teaching & Coaching*
>> *Phone: +54-011*-4893-2057
>> *Twitter: @HernanWilkinson*
>> *site: http://www.10Pines.com <http://www.10pines.com/>*
>> Address: Alem 896, Floor 6, Buenos Aires, Argentina
>> --
>> Cuis-dev mailing list
>> Cuis-dev at lists.cuis.st
>> https://lists.cuis.st/mailman/listinfo/cuis-dev
>>
>
>
> --
> Juan Vuletichcuis.stgithub.com/jvuletichresearchgate.net/profile/Juan-Vuletichindependent.academia.edu/JuanVuletichpatents.justia.com/inventor/juan-manuel-vuletichlinkedin.com/in/juan-vuletich-75611b3twitter.com/JuanVuletich
>
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>
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