Re: foreign predicate not working (one more observation)

On 19/jul/2004, at 15:25, Saurabh Bhatla wrote:

> :- foreign(get_event_ob(+string,-string)).
>
> :-object(receiver).
>
> 	:-public(receive/1).
> 	:-public(validate/1).
> 	:-public(get_event_ob/2).
> 	
> 	receive(Event).
>
> 	validate(Event):-
> 		self(Self),
> 		Self::get_event_ob(Event,Object),
> 		write(Object),	
> 		write('<-object found for event->'),
> 		write(Event),nl.
>
> 	validate(Event):-
> 		write('No object found for event->'),
> 		write(Event),nl.
> 		
>
> :-end_object.

Note that, because get_event_ob/2 is _declared_ as a _public predicate_ 
inside the object receiver, calls such as the following one:

> 		Self::get_event_ob(Event,Object),

always fail without error as get_event_ob/2 is within the scope of 
Self. Being a static predicate with no clauses, means that the calls to 
it always fail (you could be declaring a predicate which would only be 
defined in descendant objects).

Cheers,

Paulo


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Paulo Jorge Lopes de Moura
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