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devel / comp.lang.prolog / Re: Preventing further Brainwash by Logtalk

Re: Preventing further Brainwash by Logtalk

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Subject: Re: Preventing further Brainwash by Logtalk
From: bursejan@gmail.com (Mostowski Collapse)
Injection-Date: Sat, 11 Sep 2021 01:02:35 +0000
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by: Mostowski Collapse - Sat, 11 Sep 2021 01:02 UTC

Here is an easier test case for overflow. If you know IEEE floats
a little bit, and your Prolog system provides them, try this:

In Trealla, yeah the float display bug is gone:

Trealla Prolog (c) Infradig 2020-2021, v1.13.5-1-g36f32
?- X is float(1<<1023).
X = 8.98846567431158e+307.

?- X is float(1<<1024).
uncaught exception: error(evaluation_error(float_overflow),float/1)
true.

Unfortunately there is still a parsing error:

?- X = 8.98846567431158e+307.
Error: syntax error parsing number, line 0, ''
true.

So cannot close this ticket.

The Logtalk nonsense with 7^7^7 is from here:
https://github.com/LogtalkDotOrg/logtalk3/blob/09e996f53e561e8f2cfacb7ccf73562a60d319e9/tests/prolog/unbounded/tests.lgt#L260

I would expect testing parsing/unparsing before testing overflow.

Mostowski Collapse schrieb am Samstag, 11. September 2021 um 02:53:31 UTC+2:
> Logtalk nonsense can always be topped by other Logtalk
> nonsense. Interesting test case:
>
> test(lgt_unbounded_sqrt_01, error(evaluation_error(float_overflow))) :-
> _ is sqrt(7^7^7).
>
> How long does it take to compute 7^7^7 in Trealla?
>
> ?- time(_ is 7^7^7).
> Time elapsed 0,325 secs
> true.
>
> How long does it take in SWI-Prolog:
>
> ?- time(_ is 7^7^7).
> % 1 inferences, 0.013 CPU in 0.014 seconds (87% CPU, 79 Lips)
> true.
>
> LoL
> Mostowski Collapse schrieb am Freitag, 10. September 2021 um 11:24:40 UTC+2:
> > I wonder how Logtalk runs test cases towards it back-ends. For
> > example the Trealla back-end. Please Logtalk nonsense try this:
> >
> > % echo $LANG
> > de_CH.UTF-8
> >
> > % trealla/tpl
> >
> > Trealla Prolog (c) Infradig 2020-2021, v1.13.4-2-g266e8
> > ?- X is float(30000000000000)-30000000000000000.
> > X = -2.0,997e+16.
> >
> > ?- X = -2.0,997e+16.
> > Error: syntax error parsing number, line 0, ''
> >
> > LoL

Subject	Author
Re: Preventing further Brainwash by Logtalk	Mostowski Collapse