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Work slicing can simulate AbortController (Was: Summer Challenge: libSQL = Prolog+Modes [VDBE versus π-WAM])

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Hi,

In reality alread Web Workers pose quite
challenge to control and diagnose them,
not only WebGPU. For example Ciao Prolog Playground

never managed, so far, to provide a proper
Prolog interrupt, to their WAM running inside
a worker. If you do Ctrl-C it will loose the

state of the dynamic database. Since it is a
cold and hard Worker.terminate() and you have to
restart the single Web Worker used for the WAM.

Remember when fetch() had no AbortController? So
while fetch can hardly be sliced, waiting for
remote servers to do something. A local GPU (even

when dedicated card and not accelerator) is
easier to slice, especially when it runs Hack VM.
The Dogelog Player has even register_interrupt() to

define promises that are uniformly Ctrl-C. SWI-Prolog
Tinker adopted this pattern from Dogelog Player,
and is better off then Ciao Prolog Playground:

function sleep_promise(buf, delay) {
     return new Promise(resolve => {
         function handler() {
             register_interrupt(buf, () => {});
             resolve();
         }
         let timer = setDelay(handler, delay);
         register_interrupt(buf, () => {
             clearTimeout(timer);
             register_interrupt(buf, () => {});
             resolve()
         });
     });
}

Not everybody might agree to do it like
that. Even SWI-Prolog might use a variation.
The above is for Dogelog Player where $YIELD/1,

is very primitive, can only handle fullfilment,
no rejects. So you have to wrap your promise
of interest into another promise. Add work slicing

and you can do a soft terminate() without state loss.

Bye

Mild Shock schrieb:
> Hi,
> 
> Woa! Thats a very sad and non fitting statement:
> 
> "This was before I was indoctrinated into
> ISO Prolog and the ways of monotonic logic
> programming. Shen Prolog has many semantic
> and syntactic limitations that Scryer Prolog
> does not. Also, I now know constraints are a
> much better, purer solution to the problems
> mode declarations were meant to address"
> https://github.com/mthom/scryer-prolog/issues/3410#issuecomment-5030471183
> 
> Ok, here is the summer challenge, thats the easy one:
> 
>      SQL --> Prolog --> WAN
> 
> Here come two variations, slightly mindboggling maybe?
> 
>      SQL --> AST --> VDBE
> 
>      SQL --> Prolog+Modes --> π-WAM
> 
> Bye
> 
> BTW: What is VDBE? Some abstract machine, that can
> be used to run SQL, following some ideas here:
> 
> Database Co-Design With Asynchronous I/O
> https://penberg.org/papers/penberg-edgesys24.pdf
> 
> Or to run Doom:
> 
> Doom on the Turso VDBE
> https://github.com/tursodatabase/turso-vdbe-doom-example
> 
> What if we would run Doom with π-WAM, an a GPU,
> using multiple shaders. We could add some ray tracing.
> 
> Mild Shock schrieb:
>> Hi,
>>
>> Mostlikely for high performance computing à la,
>> the Actor/Erlang model is dead, they might rely
>> on MPMC (Multiple Producer, Multiple Consumer)
>>
>> queue entities separate from the threads. The
>> ISO Prolog multi-threading support had also such
>> threads. But besides that was also Actor/Erlang
>>
>> leaning in practice, like SWI, where threads
>> have some default queues:
>>
>>  > KOAN/Fortran-S was an early 1990s research programming
>>  > system for distributed-memory multiprocessors . Developed
>>  > at ENS Lyon in the early 1990s . Often listed alongside
>>  > other historical parallel programming efforts.
>>  >
>>  > The Message Passing: The research explicitly
>>  > compared the SVM approach against message passing
>>  > on the same hardware . The finding was that SVM
>>  > could achieve good performance without the low-level
>>  >
>>  > complexity of managing explicit messages, though
>>  > the best results often came from a hybrid approach (sic!)
>>
>> So an actor is basically a Thread and Mailbox
>> conflation. While a MPMC queue is a kind of
>> separate Mailbox, where multiple "actors" can
>>
>> read from and write from. A kind of localized
>> Linda Tuple store. Which Programming language did
>> adopted the non-Actor pi-calculus model?
>>
>> Right golang with its channels.
>>
>> Bye
>>
>> Mild Shock schrieb:
>>> Hi,
>>>
>>> Usual question:
>>>
>>>  > Why implement both pre-emptive threading
>>> AND cooperative tasks/engines?
>>>
>>> I had implemented the ISO proposal in formerly Jekejeke
>>> Prolog, you find the ISO proposal here:
>>>
>>> ISO/IEC DTR 13211–5:2007
>>> Prolog multi-threading support
>>> https://logtalk.org/plstd/threads.pdf
>>>
>>> But the ISO proposal doesn't match modern WebGPU APIs,
>>> where your logical threads can live remotely in a dedicated GPU
>>>
>>> in the VRAM there, and where you would have launch
>>> parameters that say: Hey please run 4096 compute
>>>
>>> shaders for me, that have independet thread state. Using
>>> cooperative multi-tasking as the orchestrator works well.
>>>
>>> Bye
>>>
>>> Mild Shock schrieb:
>>>> Hi,
>>>>
>>>> How would we do a reverse sorted map?
>>>>
>>>> I find in Java:
>>>>
>>>> TreeMap(Comparator<? super K> comparator)
>>>> Constructs a new, empty tree map, ordered
>>>> according to the given comparator.
>>>> https://docs.oracle.com/javase/8/docs/api/java/util/TreeMap.html
>>>>
>>>> Or in Dogelog Player:
>>>>
>>>> tree_new(T):
>>>> tree_new(T, F):
>>>> The predicate succeeds in R with a new red-black tree.
>>>> The binary predicate allows specifying a term compare F.
>>>> https://www.dogelog.ch/typtab/doclet/book/12_lang/05_libraries/03_util/06_tree.html 
>>>>
>>>>
>>>> Here is an example, using the destructive API. But
>>>> the same constructor works also for the non-destructive API.
>>>>
>>>> ?- tree_new(_T), tree_add(_T, 0rInf, foo),
>>>>     tree_add(_T, 0rNaN, bar), tree_pairs(_T, L).
>>>> L = [0rNaN-bar, 0rInf-foo].
>>>>
>>>> And now using a comparator modifier, aggregate with a comparator,
>>>> as a closure. Some Joy of Higher Order logic programming:
>>>>
>>>> reverse(C, R, X, Y) :- call(C, R, Y, X).
>>>>
>>>> ?- tree_new(_T,reverse(compare)), tree_add(_T, 0rInf, foo),
>>>>     tree_add(_T, 0rNaN, bar), tree_pairs(_T, L).
>>>> L = [0rInf-foo, 0rNaN-bar].
>>>>
>>>> ?- tree_new(_T,reverse(reverse(compare))), tree_add(_T, 0rInf, foo),
>>>>     tree_add(_T, 0rNaN, bar), tree_pairs(_T, L).
>>>> L = [0rNaN-bar, 0rInf-foo].
>>>>
>>>> Just toying around with my new NaNs.
>>>>
>>>> Have Fun!
>>>>
>>>> Bye
>>>>
>>>> Mild Shock schrieb:
>>>>> Hi,
>>>>>
>>>>> Functional requirement:
>>>>>
>>>>> ?- Y = g(_,_), X = f(Y,C,D,Y), term_singletons(X, L),
>>>>>     L == [C,D].
>>>>>
>>>>> ?- Y = g(A,X,B), X = f(Y,C,D), term_singletons(X, L),
>>>>>     L == [A,B,C,D].
>>>>>
>>>>> Non-Functional requirement:
>>>>>
>>>>> ?- member(N,[5,10,15]), time(singletons(N)), fail; true.
>>>>> % Zeit 1 ms, GC 0 ms, Lips 4046000, Uhr 11.08.2025 01:36
>>>>> % Zeit 3 ms, GC 0 ms, Lips 1352000, Uhr 11.08.2025 01:36
>>>>> % Zeit 3 ms, GC 0 ms, Lips 1355333, Uhr 11.08.2025 01:36
>>>>> true.
>>>>>
>>>>> Can your Prolog system do that?
>>>>>
>>>>> P.S.: Benchmark was:
>>>>>
>>>>> singletons(N) :-
>>>>>     hydra2(N,Y),
>>>>>     between(1,1000,_), term_singletons(Y,_), fail; true.
>>>>>
>>>>> hydra2(0, _) :- !.
>>>>> hydra2(N, s(X,X)) :-
>>>>>     M is N-1,
>>>>>     hydra2(M, X).
>>>>>
>>>>> Bye
>>>>
>>>
>>
> 

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