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The missing genius of Web Prolog (Was: The lost Genius of GNU Prolog FFI)

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Hi,

I have some doubt that Web Prolog captures the
wisdom of 70 years of distributed database engineering.
Or maybe the Trinity Web Prolog concept paper does

not talk about it. But the general structure of SQL queries is:

SELECT projection
FROM source
WHERE condition

Now I have a problem with Web Prolog when I would like
to do very simple remote things like for example, which can be
highly optimized in traditional WAM based Prolog systems,

the way anonymous variables can be represented. You see
this in the GNU Prolog FFI, in the C declarations from <gprolog.h>,
where an argument can be marked as wanted on return or not:

?- ..., PID ! person(ID, _, _, AGE, _), ...

What a Web Prolog might see at runtime is only:

?- ..., 9167 ! person(3524, _1, _2, _3, _4), ...
The pengine, although it can do paging or whatever, will
then happily send back over the wire a very large JSON
packet which will have the answer in its data field:

{
    ...
    data:{"_1":..., "_2":...", "_3":..., "_4":...}
}

But from the intention of the original query we would like only:

{
    ...
    data:{"_3":...}
}

So while Web Prolog gives me some traits of a ResultSet
from SQL, like paging. I think a mechanism for select projection
is missing, while SQL happily does that as well in its ResultSet.

Its quite a tricky problem, since it shatters the whole idea of
a simple (!)/2 binary operator for Prolog based RPC. Maybe it
can be solved on the compiler side with an analysis that

provides the GNU Prolog FFI flags. But then the Prolog based
RPC becomes more than a new built-in with a beautifully
looking (!)/2 binary operator, it would also require some

intervention in compiler technique from the Prolog system.

Bye

Mild Shock schrieb:
> Hi,
> 
> We really find a lost Genius in GNU Prolog FFI.
> It has this wonderful thing. The field "unify"
> controls whether the actual argument must
> 
> be unified at the exit of the C function.
> 
> 10.3.6  Input/output arguments
> typedef struct
>      {
>       PlBool is_var;
>       PlBool unify;
>       union
>          {
>           PlLong l;
>           char  *s;
>           double d;
>          }value;
>      } PlFIOArg;
> 
> Judging from just looking at it, one can basically
> communicate "don't care" arguments, usuall expressed
> as "_" i.e. annonymous variables, or some variants
> 
> of Prolog systems also allow "_Name", but effectively
> variables that only occure at one call site location.
> But why is it lost. It is slowly subject to bit rot.
> 
>  > www.gprolog.org verwendet ein ungültiges Sicherheitszertifikat.
>  >
>  > Das Zertifikat gilt nur für folgende Namen: trantor.univ-paris1.fr,
>  > *.univ-paris1.fr, univ-paris1.fr, *.pantheonsorbonne.fr,
>  > pantheonsorbonne.fr
>  >
>  > Fehlercode: SSL_ERROR_BAD_CERT_DOMAIN
> 
> Some older browsers fall back to HTTP, some newer
> browsers do not fall back to HTTP, and require an
> exceptions. I dunno how this affects your FFI project
> 
> and some merits of using GNU Prolog. But somehow projects
> become quickly outdated, either from the inside or from
> the outside. I think its an error to think one can make
> 
> a website, and then forget it for decades, you basically
> have to internally reviewed it every 2-3 years. So half
> dead projects like GNU Prolog based on C will disappear
> 
> in favor to for example Rust projects, simply because
> Rust might be more attentive and more alive now,
> until Rust is replaced by the next wave of programming
> 
> languages. Its the same with repositories that were
> accessible via FTP and had PS files, nobody can access
> them easily nowadays. In a few months you might need
> 
> to place an ai.txt on your website, and add some
> certificate to it, to prove your code was made by a
> human and not by a robot, because of cybersecurity
> 
> and alignment issues.
> 
> Bye
> 

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The lost Genius of GNU Prolog FFI Mild Shock <janburse@fastmail.fm> - 2026-08-24 17:03 +0200
  The missing genius of Web Prolog (Was: The lost Genius of GNU Prolog FFI) Mild Shock <janburse@fastmail.fm> - 2026-08-24 17:06 +0200
    Some variable scoping tricks (Was: The missing genius of Web Prolog) Mild Shock <janburse@fastmail.fm> - 2026-08-24 17:07 +0200
  How is "unify" control done in Dogelog Player (Was: The lost Genius of GNU Prolog FFI) Mild Shock <janburse@fastmail.fm> - 2026-08-24 17:26 +0200

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