-------- Original Message -------- Subject: Re: Any Prolog language lawyer out there? Date: Wed, 20 Oct 2004 14:09:14 +0200 From: Bart Demoen <bmd@cs.kuleuven.ac.be> Organization: KULeuvenNet Newsgroups: comp.lang.prolog References: <41750912.8040102@cs.unipr.it> <1098196164.417498@seven.kulnet.kuleuven.ac.be> <slrncnaat8.jkn.jan@ct.xs4all.nl> <87acuijutl.fsf@gondolin.bb.bawue.de> <1098259920.942884@seven.kulnet.kuleuven.ac.be> I wrote:

Goal : integer(- 4) Specification result : Must fail

Goal : integer(-4) Specification result : Must succeed

So it seems that the space between the - and the 4 is important.

I do not have the final copy of the standard, and although I do remember that there has been discussion about it, I do not remember the final outcome, so can anybody check that's indeed what the standard says ?

I got hold of a standard ... It says at the end of section that Jens was quoting from: "A term which is the name - followed directly by a numeric constant, denotes the cirresponding negative constant" In the standard "directly" means something like "with no space in between". That decides the issue I think: - 4 should not be read as a negative integer; and -4 should be read as a negative integer. Cheers Bart Demoen -- Prof. Roberto Bagnara Computer Science Group Department of Mathematics, University of Parma, Italy http://www.cs.unipr.it/~bagnara/ mailto:bagnara@cs.unipr.it