Re: Singleton variable in branch

Feliks Kluzniak <[email protected]> Mon, 16 Dec 2013 17:09:43 +0100

Newsgroups	gmane.comp.ai.prolog.swi
Message-ID	<[email protected]>

On Dec 16, 2013, at 16:58, FERNANDO SAENZ PEREZ <[email protected]> wrote:

> p(A) :-
>        (   functor(A, _, B)
>        ->  (   foo(B)
>            ->  foo(B)
>            ;   foo(B)
>            )
>        ;   foo(B)
>        ).
> true.
> 
> %%%%%%%%%%%%%%%%%%%%%%
> 
> I do not understand the warning. I think that B is used in all branches,
> isn't it?

It seems to me that if the functor/3 fails, then the B in the last branch is indeed a singleton.  Am I missing something?

Regards,
— Feliks