Re: Any Prolog language lawyer out there?

From: Bart Demoen (bmd_at_cs.kuleuven.ac.be)
Date: 10/20/04

  • Next message: Jan Wielemaker: "Re: SWI-prolog, XPCE help" 
    Date: Wed, 20 Oct 2004 14:09:14 +0200

    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

  • Next message: Jan Wielemaker: "Re: SWI-prolog, XPCE help"

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