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Groups > comp.lang.prolog > #14527

the desease of C code overkill (Was: variable ordering guarantees in term_singletons/2)

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I don't understand why some Prolog systems tend to gravitate
more and more into implementing everything in C. I don't see
any advantage. Take listing/1, do you get clauses faster and better

printed when you use C? Starting with the pretty/1 implementation
in Prolog itself I am pretty sure things can be enhanced. Similarly a
top level written in pure Prolog can be advantageous.

SWI-Prolog has a similar deseases of C code overkill sometimes.

The only argument for C is maybe a different datastructure for
variable_names. But the algorthm I posted on comp.lang.prolog
doesn't need a different datastructures, its just a

pairing algorithm. Running through both the term_variables
and term_singleton lists in parallel. So there is no advantage of
C code at all.

Mild Shock schrieb:
> Hi,
> 
> People from Vienna were always a little strange.
> Why not adopt term_singletons/2 its already around
> for a while. You can do quite some magic with it.
> 
> Example: Determining singletons during listing,
> from Dogelog Player library(tester/tools):
> 
> % sys_listing_write(+Term, +Stream)
> sys_listing_write(C, T) :-
>     term_variables(C, V),
>     term_singletons(C, A),
>     sys_listing_names(V, A, 0, N),
>     write_term(T, C, [quoted(true), variable_names(N), format(true)]),
>     sys_answer_period(T).
> 
> If term_singletons/2 has the same variable ordering
> guarantees, i.e. left to right, as in term_variables/2
> you can use an algorithm without expensive lookup,
> 
> sys_listing_names([], _, _, []).
> sys_listing_names([X|L], [Y|R], K, ['_'=X|S]) :- X==Y, !,
>     sys_listing_names(L, R, K, S).
> sys_listing_names([X|L], A, K, [N=X|R]) :-
>     sys_listing_name(K, N),
>     J is K+1,
>     sys_listing_names(L, A, J, R).
> 
> Just run along the two lists , if something is both in
> the term_variables/2 and term_singletons/2 list, generate
> a '_' name, otherwise generate a synthetic name.
> 
> Bye
> 
> Mild Shock schrieb:
>> Hi,
>>
>> The development of Trealla Prolog and Scryer Prolog
>> looks like a random search in a mental ocean.
>>
>> It is like Prolog Development à la Sigmund Freud,
>> you have only to dig deep enough, and a solution
>>
>> will pop up. Otherwise blame your mother or other
>> relatives that raised you for supression.
>>
>> LoL
>>
>> Bye
>>
>> Examples: Still clueless how to detect singletons?
>> https://github.com/trealla-prolog/trealla/issues/743

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  Re: Ulrich Neumerkel is like Ozzy Osbourne Mild Shock <janburse@fastmail.fm> - 2024-12-05 11:33 +0100
    Re: Ulrich Neumerkel is like Ozzy Osbourne Mild Shock <janburse@fastmail.fm> - 2024-12-05 11:41 +0100
      Re: Ulrich Neumerkel is like Ozzy Osbourne Mild Shock <janburse@fastmail.fm> - 2024-12-05 11:44 +0100
        Prolog Development à la Sigmund Freud (Was: Ulrich Neumerkel is like Ozzy Osbourne) Mild Shock <janburse@fastmail.fm> - 2025-05-25 09:46 +0200
          variable ordering guarantees in term_singletons/2 (Was: Prolog Development à la Sigmund Freud) Mild Shock <janburse@fastmail.fm> - 2025-05-25 09:57 +0200
            My stupid Dogelog Player falls back to _<number> (Was: variable ordering guarantees in term_singletons/2) Mild Shock <janburse@fastmail.fm> - 2025-05-25 10:18 +0200
            the desease of C code overkill (Was: variable ordering guarantees in term_singletons/2) Mild Shock <janburse@fastmail.fm> - 2025-05-28 16:12 +0200
              Quintus Folks were not hating Prolog that much (Was: the desease of C code overkill) Mild Shock <janburse@fastmail.fm> - 2025-05-28 16:32 +0200
  Ciao Prolog inspired Test Case (Re: Ulrich Neumerkel is like Ozzy Osbourne) Mild Shock <janburse@fastmail.fm> - 2025-05-27 07:45 +0200

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