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  • User @false is exaggerating as usual

    From Mild Shock@janburse@fastmail.fm to comp.lang.prolog on Tue Oct 7 10:30:03 2025
    From Newsgroup: comp.lang.prolog

    Hi,

    UWN wrote:

    ?- call((!,false->true;true)).
    false, unexpected.
    true. % expected, but not found. Works in 14 other systems.

    Nope, I get:

    /* Dogelog Player */
    ?- call((!,false->true;true)).
    🚨 Fehler: Prädikat false/0 undefiniert.
    user auf 1

    But this here works:

    /* Dogelog Player */
    ?- call((!,fail->true;true)).
    true.

    LoL

    Bye
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  • From Mild Shock@janburse@fastmail.fm to comp.lang.prolog on Tue Oct 7 10:32:26 2025
    From Newsgroup: comp.lang.prolog

    Hi,

    Because Prolog has no false/0. It
    only has fail/0, everything else is
    Negation as Failure interpretation:

    \+ P If the goal P has a solution, fail,
    otherwise succeed. This is not real negation
    ("P is false"), but a kind of pseudo-negation
    meaning "P is not provable". It is defined as if by

    \+(P) :- P, !, fail.
    \+(_).

    https://userweb.fct.unl.pt/~lmp/publications/online-papers/DECsystem-10%20PROLOG%20USER%27S%20MANUAL.pdf

    Bye

    Mild Shock schrieb:
    Hi,

    UWN wrote:

    ?- call((!,false->true;true)).
       false, unexpected.
       true. % expected, but not found. Works in 14 other systems.

    Nope, I get:

    /* Dogelog Player */
    ?- call((!,false->true;true)).
    🚨 Fehler: Prädikat false/0 undefiniert.
        user auf 1

    But this here works:

    /* Dogelog Player */
    ?- call((!,fail->true;true)).
    true.

    LoL

    Bye

    --- Synchronet 3.21a-Linux NewsLink 1.2
  • From Mild Shock@janburse@fastmail.fm to comp.lang.prolog on Tue Oct 7 19:06:31 2025
    From Newsgroup: comp.lang.prolog

    Hi,

    What happened to Julio Di Egidio full time Nazi
    Retard? Did he **plonk** himself. Or maybe he
    is deep inside Natural Number Game:

    "An introduction to mathematical proof.
    In this game, we will build the basic theory
    of the natural numbers {0,1,2,3,4,...} from scratch." https://adam.math.hhu.de/#/g/leanprover-community/nng4

    And is now facing the final boss:

    "Let's now begin our approach to the final
    boss, by proving some more subtle facts
    about powers." https://adam.math.hhu.de/#/g/leanprover-community/nng4/world/Power/level/6

    LoL

    Bye

    Mild Shock schrieb:
    Hi,

    Because Prolog has no false/0. It
    only has fail/0, everything else is
    Negation as Failure interpretation:

    \+ P If the goal P has a solution, fail,
     otherwise succeed. This is not real negation
     ("P is false"), but a kind of pseudo-negation
     meaning "P is not provable". It is defined as if by

     \+(P) :- P, !, fail.
     \+(_).

    https://userweb.fct.unl.pt/~lmp/publications/online-papers/DECsystem-10%20PROLOG%20USER%27S%20MANUAL.pdf


    Bye

    Mild Shock schrieb:
    Hi,

    UWN wrote:

    ?- call((!,false->true;true)).
        false, unexpected.
        true. % expected, but not found. Works in 14 other systems.

    Nope, I get:

    /* Dogelog Player */
    ?- call((!,false->true;true)).
    🚨 Fehler: Prädikat false/0 undefiniert.
         user auf 1

    But this here works:

    /* Dogelog Player */
    ?- call((!,fail->true;true)).
    true.

    LoL

    Bye


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