Re: [Info-gnuprologjava] Adding facts to environment dynamicly

[Dominik Schmeiser]

Hi Daniel,

thanks for your quick reply.

Unfortunately it still does not work. We have two Prolog-Files.

File 1:
 foo(bar1).

File 2:
 :- dynamic(foo/1).
 invoke(R) :- assert[a/z](foo(bar2)).

Both files are loaded to the environment (using
environment.ensureLoaded(AtomTerm.get(<path>))) and we have still an
existence error for "assert" and the permission error for asserta & -z when
we try to use invoke.
We were not sure if the dynamic-predicate is really used, so we extended
the file to

invokeD(R) :- dynamic(foo/1).

When we then called the invokeD we got an existence-error, too:
gnu.prolog.vm.PrologException: error(existence_error(procedure,dynamic /
1),error)

We're using verion 0.2.6.

We looked through some bug reports and found minimal examples like this:
:- dynamic(aFoo/1).
:- initialization(assertz(aFoo(1)),aFoo(1),assertz(aFoo(2)),aFoo(2)).

Our experience implies that this - especially the ":-
dynamic(aFoo/1)."-part - works not in our environment.
Is there probably something we're missing in our Java-code?

environment = new Environment();
environment.ensureLoaded(AtomTerm.get(<path1>));
environment.ensureLoaded(AtomTerm.get(<path2>));
                
interpreter = environment.createInterpreter();
environment.runInitialization(interpreter);

VariableTerm v = new VariableTerm("vTerm");
Term[] a = {v};
CompoundTerm c = new CompoundTerm("invoke", a);
                        
Interpreter.Goal goal = interpreter.prepareGoal(c);
int result = interpreter.execute(goal);

We really have no idea where we're going wrong.

Thanks for your time and help! :-)

Dominik


On Mon, 06 Jun 2011 13:20:40 +0100, Daniel Thomas <address@hidden> wrote:
> Hello,
> 
> Before you can use assert[a,z] on a predicate you first need to declare
> it to be dynamic e.g.
> :- dynamic(foo/1).
> 
> I hope that helps,
> 
> Daniel
> 
> On Sun, 2011-06-05 at 14:32 +0200, Dominik Schmeiser wrote:
>> Hi all,
>> 
>> Me and my collegue are working with GPJ on an project for the
> university.
>> we have a Prolog-Environment which already loaded some facts. (using
>> environment.ensureLoaded(...))
>> 
>> e.g.
>> foo(bar1).
>> foo(bar2).
>> 
>> Now we try to invoke a rule (using interpreter.execute(...)).
>> This rule should create some new facts in the environment,
>> 
>> e.g.
>> invoke :- assert( foo(bar3) ).
>> 
>> Our problem:
>> When we use the predicate "assert" t is not recognized:
>> - gnu.prolog.vm.PrologException: error(existence_error(procedure,assert
> /
>> 1),error)
>> When we try "asserta" or "assertz" we have another error that implies we
>> would like to override the facts which are already in the environment:
>> - gnu.prolog.vm.PrologException:
>> error(permission_error(modify,static_procedure,foo / 1),error)
>> 
>> Our question:
>> Is there any possibility to add facts to the environment dynamicly?
>> 
>> Please note that I'm not on the mailing list so please reply directly.
>> 
>> TIA
>> 
>> Dominik
>> 
>> 
>> 
>>