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variable ordering guarantees in term_singletons/2 (Was: Prolog Development à la Sigmund Freud)

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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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Ulrich Neumerkel is like Ozzy Osbourne Mild Shock <janburse@fastmail.fm> - 2024-12-05 11:26 +0100
  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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