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Groups > comp.lang.prolog > #14651
| From | Mild Shock <janburse@fastmail.fm> |
|---|---|
| Newsgroups | comp.lang.prolog |
| Subject | DCG is easily affected (Was: The Ghosts in my Cabinet: Indexing) |
| Date | 2025-07-11 09:38 +0200 |
| Message-ID | <104qf0n$21rh6$1@solani.org> (permalink) |
| References | <104o5kc$20fno$1@solani.org> |
Interestingly, DCG is also affect. Here a
DCG take of an append app/3, it has the 2nd
and 3rd argument swapped:
?- [user].
app([]) --> [].
app([X|Y]) --> [X], app(Y).
^D
Looks like an append, taking the argument swap
into account, the A=B is redundant, could
be optimized away:
/* SWI-Prolog 9.3.25 */
?- listing(app/3).
app([], A, B) :-
A=B.
app([A|B], [A|C], D) :-
app(B, C, D).
And works like an append, again taking the
argument swap into account:
?- app([1],X,[2,3]).
X = [1, 2, 3].
Now the multi-argument indexing test, still
taking the argument swap into account;
/* ECLiPSe Prolog 7.1beta #13 */
[eclipse 3]: app(X, [1], Y).
X = []
Y = [1]
Yes (0.00s cpu, solution 1, maybe more) ? ;
X = [1]
Y = []
Yes (0.00s cpu, solution 2)
Versus:
/* SWI-Prolog 9.3.25 */
?- app(X, [1], Y).
X = [],
Y = [1] ;
X = [1],
Y = [] ;
false.
Mild Shock schrieb:
> I am currently doing a re-evaluation of an old
> Prolog system, checking what features I could adopt.
> This is unlike the current trend where people have
> turned their focus on GUIs, like XPCE,
>
> or a are stuck in an endless loop of parser
> problems, like in Trealla. But I would nevertheless
> share my finding. Take this simple example of
> a list append:
>
> app([], X, X).
> app([X|Y], Z, [X|T]) :- app(Y, Z, T).
>
> ECLiPSe Prolog gives me, only one redo question
> in the top-level:
>
> /* ECLiPSe Prolog 7.1beta #13 */
> [eclipse 2]: app(X,Y,[1]).
>
> X = []
> Y = [1]
> Yes (0.00s cpu, solution 1, maybe more) ? ;
>
> X = [1]
> Y = []
> Yes (0.00s cpu, solution 2)
>
> In SWI-Prolog I find, two redo questions
> in the top.level:
>
> /* SWI-Prolog 9.3.25 */
> ?- app(X,Y,[1]).
> X = [],
> Y = [1] ;
> X = [1],
> Y = [] ;
> false.
>
> I know SWI-Prolog handles lists differently
> than other Prolog terms during indexing. Could
> this be the reason? Or maybe that the call is
> not “hot” enough, so it doesn’t get JIT-ed.
>
> ECLiPSe Prolog does it on the very first call,
> and I assume its due to a kind of index on
> the 3rd argument.
>
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The Ghosts in my Cabinet: Indexing Mild Shock <janburse@fastmail.fm> - 2025-07-10 12:45 +0200
Observed while watching FAIL/REDO ports (Was: The Ghosts in my Cabinet: Indexing) Mild Shock <janburse@fastmail.fm> - 2025-07-10 12:46 +0200
Shocking Revelation: No eGovernment can trust Prolog! (Was: Observed while watching FAIL/REDO ports) Mild Shock <janburse@fastmail.fm> - 2025-07-10 13:26 +0200
Easier certification with 100% Prolog Prolog? (Was: Shocking Revelation: No eGovernment can trust Prolog!) Mild Shock <janburse@fastmail.fm> - 2025-07-10 14:05 +0200
Doing a Prolog system without any iterator API (Was: Easier certification with 100% Prolog Prolog?) Mild Shock <janburse@fastmail.fm> - 2025-07-10 14:14 +0200
The headache with JIT indexing: Native -> Prolog (Was: Doing a Prolog system without any iterator API) Mild Shock <janburse@fastmail.fm> - 2025-07-10 14:40 +0200
Just lets burn another candle for Barty Boy (Was: The headache with JIT indexing: Native -> Prolog) Mild Shock <janburse@fastmail.fm> - 2025-07-10 18:13 +0200
Physics PhDs might never have heard of Quantifier Eliminations (Re: Just lets burn another candle for Barty Boy) Mild Shock <janburse@fastmail.fm> - 2025-07-10 18:33 +0200
How long willl I piss on Bart Demoen (Was: Physics PhDs might never have heard of Quantifier Eliminations) Mild Shock <janburse@fastmail.fm> - 2025-07-10 18:39 +0200
But I shouldn't waste too much time (Was: How long willl I piss on Bart Demoen) Mild Shock <janburse@fastmail.fm> - 2025-07-10 19:13 +0200
DCG is easily affected (Was: The Ghosts in my Cabinet: Indexing) Mild Shock <janburse@fastmail.fm> - 2025-07-11 09:38 +0200
The headache an eGovernment might get from Prolog (Was: DCG is easily affected) Mild Shock <janburse@fastmail.fm> - 2025-07-15 15:20 +0200
Wait till they find out about compare/3 (Was: The headache an eGovernment might get from Prolog) Mild Shock <janburse@fastmail.fm> - 2025-07-15 15:24 +0200
Corr. (Was: Wait till they find out about compare/3) Mild Shock <janburse@fastmail.fm> - 2025-07-15 15:28 +0200
eGovernements will need AGI to survive (Was: Corr. (Was: Wait till they find out about compare/3)) Mild Shock <janburse@fastmail.fm> - 2025-07-15 18:41 +0200
Having 2544 issues is probably a bad sign (Re: eGovernements will need AGI to survive) Mild Shock <janburse@fastmail.fm> - 2025-07-15 18:41 +0200
The Signal Collapse gives us System Uncertainty (Re: Having 2544 issues is probably a bad sign) Mild Shock <janburse@fastmail.fm> - 2025-07-15 19:02 +0200
Rename GitHub, to TurdPit, and make Amber Heard their CEO (Was: The Signal Collapse gives us System Uncertainty) Mild Shock <janburse@fastmail.fm> - 2025-07-15 19:52 +0200
Humans are just overwhelmed by computers (Was: eGovernements will need AGI to survive) Mild Shock <janburse@fastmail.fm> - 2025-07-16 18:59 +0200
Fishy 🐟 in Scryer Prolog and SWI-Prolog (Was: Humans are just overwhelmed by computers) Mild Shock <janburse@fastmail.fm> - 2025-07-16 20:08 +0200
So we are essentially all using Trojan Horses 🐎 daily? (Re: Fishy 🐟 in Scryer Prolog and SWI-Prolog) Mild Shock <janburse@fastmail.fm> - 2025-07-17 10:57 +0200
Strudel Rust gives Scryer Frust 💩: Try C+20 Pipes (Was: Fishy 🐟 in Scryer Prolog and SWI-Prolog( Mild Shock <janburse@fastmail.fm> - 2025-11-25 22:55 +0100
SWI-Prolog as a Test Bed for Copilots (Was: Humans are just overwhelmed by computers) Mild Shock <janburse@fastmail.fm> - 2025-07-20 14:36 +0200
Mathematics currently hates Computer Science because of AI (Re: SWI-Prolog as a Test Bed for Copilots) Mild Shock <janburse@fastmail.fm> - 2025-07-20 15:13 +0200
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