Re: Bit-manipulation in ISO Prolog

From: Nameless (news.mail_at_chello.no)
Date: 08/17/04

  • Next message: Jens Kilian: "Re: Bit-manipulation in ISO Prolog" 
    Date: Tue, 17 Aug 2004 15:13:48 +0200

    "Pere Montolio" wrote in message
    news:d0867bad.0408170058.5e355986@posting.google.com...
    > > "Nameless" <news.mail@chello.no> wrote in message
    > > ...
    >
    > I assume you know this answer for "xor":
    >
    > xor(X,Y,Z) :- Z is ( (\ X) /\ Y ) \/ ( (\ Y) /\ X ).
    >
    > (hope no typo mistakes).
    >
    > and pray that you compiler/interpreter of prolog has a good
    > optimizer.

    Right!

    > (note: in general I look always for compilers with and easy
    > interface to C, in order to be able to add small low level
    > functions).

    Pere, I think that's rather missing the point, namely the
    absence of (the very useful) 'xor' in ISO Prolog.

    >From a practical point of view, since most Prologs are
    actually implemented in C or a similar imperative language
    that has bit-meddling functions, it would be most
    surprising not to find matching Prolog predicates. Which is
    all the more reason to wonder why ISO Prolog lacks 'xor'.

    > I agree it is not a great answer, but it is all I have.

    I came up with the same solution too, but this seemed so
    clumsy I thought that there must be a better one. I guess
    not. Many thanks for confirming this, Pere. I'll be
    generous and thank Bart, too. ;)

    > PS: Do you known any good reason to do not post with a real
    > name?

    Yes. ;) 

    -- 
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  • Next message: Jens Kilian: "Re: Bit-manipulation in ISO Prolog"

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