I've asked the same question last month.
This package is in fact an attempt of Johan Brichau implement SOUL by 
reusing a Prolog package. This seems to be a work in progress.

Johan Brichau wrote:
> Hi there,
>
> The 'SOUL back to Squeak' project on squeaksource is indeed on hold 
> for now. Maybe someday a port to Squeak will be produced again, for 
> now, the official version is on the cincom store and for Visualworks 
> only.
>
> Sorry about that,
> Johan 
Then, Roel sent me two zip files, one of them ("the old one") were very 
easy to port to Squeak 3.9 in a monticello package.

Roel Wuyts wrote:
> The old one is really old ;-)
>
> I attached two versions of Soul for you. The first one (Squeak.zip) is 
> really old.
>
> The other one should work in Squeak 2.8, so I would give that one a 
> try. It even comes with installation instructions and unit tests for 
> the Prolog predicates (not really for Soul itself, sorry), etc. Have 
> fun :-) Let me know how it goes :-) 
I wish it helped ...

Guillaume Grondin

Serge Stinckwich wrote:
> Robert Shiplett a écrit :
>> I have Prolog/V back running in a PrologWorkspace under Squeak 3.9 
>> after sorting out a few compile issues (images now save/load fine 
>> with Prolog predicates compiled in Prolog and subclassses)
>>
>> Will get Squeak Map updated as soon as I have a minimal logic browser 
>> to ease compiling Prolog predicates ( at the moment files with 
>> predicates for a Prolog class need to be filed-in separately to cover 
>> a few compile glitches/gotchas ).
>>
>> Now to see how this an mesh with the BackTalk image that is available 
>> and the previous work on SOUL for Squeak.
>>
>
> BTW, what is the status of SOUL for Squeak ? There is a SqueakSource 
> projet SOUL back to Squeak : http://www.squeaksource.com/SqueakSoul.html
> but no code seems to be available ...
>
> -- 
> Serge Stinckwich
> http://doesnotunderstand.free.fr/
>
>
>
>

-- 
Guillaume Grondin
Ph.D candidate in Computer Science
===========================================
Département IA, École des Mines de Douai
941, rue Charles Bourseul - BP 10838
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Fax : (+33) (0) 3 27 71 29 17
Email: grondin at ensm-douai.fr
http://csl.ensm-douai.fr/grondin