Re: Issues with ubuntu 18.04

The Ubuntu .deb package is broken. You need to compile and install GNU =
Prolog from sources.

> On 25 Mar 2021, at 21:25, Jerry Hancock <[email protected]> wrote:
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> Hello, =20
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> Please excuse me for asking about something so old.  I installed =
gnu-prolog 1.4.5 on ubuntu server 18.04.  The underlying hardware is an =
HP dl380 with at least 24 cores.  I had some code that runs perfectly =
but slowly on other servers so I thought I would try my cloud server.
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> The test code is simple and instantiated in sit3.pl:
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> c(blue).
> c(green).
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> sit3(X):-c(X).
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> On my other installations, the first solution X=3Dblue is returned as =
expected..  On the ubuntu server 18.04 , I get an error, "uncaught =
exception error(existence_error(procedure,c/0),sit3/0) =E2=80=9C =
implying that c/0 doesn=E2=80=99t exist but I=E2=80=99m not calling c/0 =
I=E2=80=99m calling c/1 as below:
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> {trace}
> | ?- sit3(X).
>       1    1  Call: sit3(_24) ?=20
>       2    2  Call: c ?=20
>       2    2  Exception: c ?=20
>       1    1  Exception: sit3(_24) ?=20
> uncaught exception: error(existence_error(procedure,c/0),sit3/0)
> {trace}
> | ?-=20
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> If I assert the clauses from the terminal, all is well.
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> If I run c(X), trace returns:
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> | ?- c(X).
>       1    1  Call: c(_24) ?=20
>       1    1  Exit: c(blue) ?=20
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> X =3D blue ?=20
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> Or=20
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> | ?- asserta(cc(blue)).
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> yes
> | ?- asserta(cc(green)).
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> yes
> | ?- asserta((sit33(X):-cc(X))).
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> yes
> | ?- sit33(X).
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> X =3D green ?=20
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> This is a very simple example that should work.  I=E2=80=99ve been =
working with prolog since the late 80=E2=80=99s and unless there is an =
ini file that is note allowing the clauses to be added correctly, I =
could't find it.
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> Thanks