Re: not()

Jasper Taylor <[email protected]> Wed, 2 May 2007 09:47:24 +0100

Newsgroups	gmane.comp.gnu.prolog.bugs
Message-ID	<[email protected]>

On Tuesday 01 May 2007 18:14:00 Guido Leisker wrote:
> I created a file test.pro:
>
> ---test.pro---
> female(anita).
> male(X) :- not(female(X)).
> --------------

It is not a bug. The GNU-prolog manual does not mention a not() predicate. The 
unary operator \+ does negation-by-failure, so your program should be:

female(anita).
male(X) :- \+ female(X).

Cheers
	--Jasper