Error while loading Logtalk into JIProlog

[Monikuta]

I tried loading Logtalk into JIProlog by calling:

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{roots(loader)}.

but I keep getting the following error message:

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<<< loading source file bintree... 
>>> compiling source file bintree...
compiling object bintree... 
  ERROR!    unknown_error
            in clause: map(_26219432, _33204885, _30747539) :- map(_26219432, _33204885, _30747539, _2087546)

Could you please help me solve this problem? I really need Logtalk combined with JIProlog for my bachelor degree thesis.
I have finished the Checkers game Java J2ME implementation and also the computer player's part in Logtalk having SWI-Prolog as the back-end Prolog compiler and they work fine.
What I have to do know is to integrate the computer player from Prolog into J2ME using JIProlog.

I would greatly appreciate your help.
Yours sincerely,
Monica Dogaru

[Paulo Moura]

Hi Monica!

Trying to reproduce the problem you describe results in my case in a "jvm_error('Java heap space')" when compiling the object "bintree". Trying to load only the library object "bintree" results in the same error you describe above. Changing the caluse for the map/3 to:

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map(Pred, Old, New) :-
     map1(Pred, Old, New, _).

allows the "bintree" to be compiled without errors. You've found another JIProlog bug. I'm going to send Ugo a bug report.

Best regards,

Paulo

[Monikuta]

I did the modification you suggested.
But I get the following error:

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compiling object bintree... 
  ERROR!    error(type_error(numeric_expression), context(','(:: ',') > 0, file(undefined, 0)))
            in clause: map(_10290053, t(_5384363, _32249502, _12647886, _5694431), t(_9068888, _16570805, _3743881, _8851935), _27681911) :- _27681911 =.. [_10290053, _5384363 - _32249502, _9068888 - _16570805], once(_27681911), map(_10290053, _12647886, _3743881, _17684228), map(_10290053, _5694431, _8851935, _27223263)

Is this an error in JIProlog?....cause in SWI-Prolog it worked fine.
Monica Dogaru

[Paulo Moura]

Hi Monica!

You forgot to propagate the change to the definition of predicate map/4, renaming it to map1/4.

Best regards,

Paulo

[Monikuta]

I made the following modifications:

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:- private(map1/4).
	:- meta_predicate(map1(*, *, *, ::)).
	:- mode(map1(+atom, +tree, -tree, -callable), zero_or_one).

and

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map(Pred, Old, New) :-
		map1(Pred, Old, New, _).


	map1(Pred, t(Key1, Value1, Left1, Right1), t(Key2, Value2, Left2, Right2), Goal) :-
		Goal =.. [Pred, Key1-Value1, Key2-Value2],
		once(Goal),
		map1(Pred, Left1, Left2, _),
		map1(Pred, Right1, Right2, _).
        map1(_, t, t, _).   

but I still get the following error:

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 ERROR!    unknown_error
            in clause: map(_11831860, _14522837, _10385830) :- 'map1'(_11831860, _14522837, _10385830, _4502232)

error(error(unknown_error, clause(:-(map(_15282457, _26642894, _3240908), 'map1'(_15282457, _26642894, _3240908, _11102634)))), logtalk_load(bintree))

Can you help me please?
Monica Dogaru

[Paulo Moura]

Hi Monica!

The error you're getting is due to some JIProlog bug. As much I would like to help you, I cannot spend my limited developer time debugging JIProlog. The debugging features of this Prolog compiler are limited and diagnosing its bugs implies hours of work. JIProlog simply does not seem to be reliable enough for your work (at least in its current release; the previous one I tested did not have the bugs we uncover in the last weeks). My guess is that, even if this bug is found and fixed, another bug will just pop up. My advice is for you to switch, if possible, to a well maintained Prolog compiler.

Best regards,

Paulo