[PPL-devel] Arithmetic evaluation bug in the CVS HEAD version of XSB
paul at duologues.net
Sun Sep 23 20:09:12 CEST 2007
Roberto, I agree with your sentiments and have suffered similar
frustrations. It indeed illustrates a significant departure from the
expected result and will be a surprise to most new users. Then again,
I would say that all logic programming systems are hindered in many ways
by the underlying operating systems. XSB has other value. Best
wishes - Paul
Roberto Bagnara wrote:
> Paul Broome wrote:
>> As I'm sure you know, the is/2 predicate is nonlogical. This
>> difference is also in previous versions of XSB. In this instance,
>> there is a simple alternate:
>> [broome at localhost bin]$ ./xsb-bits64
>> [xsb_configuration loaded]
>> [sysinitrc loaded]
>> XSB Version 3.1 (Incognito) of August 10, 2007
>> [x86_64-unknown-linux-gnu; mode: optimal; engine: slg-wam; gc:
>> indirection; scheduling: local]
>> | ?- [user].
>> [Compiling user]
>> side_step_term_as_arithmetic_argument_bug(Term,N) :-
>> call(N is Term).
>> [user compiled, cpu time used: 0.0090 seconds]
>> [user loaded]
>> | ?- side_step_term_as_arithmetic_argument_bug(1+1+1,N).
>> N = 3;
>> | ?-
>> End XSB (cputime 0.02 secs, elapsetime 74.23 secs)
>> I hope this helps.
> Dear Paul,
> thanks for the workaround. However, I don't understand how the fact that
> the is/2 predicate is nonlogical matters. Do you agree with me that the
> behavior I indicated witnesses a (big) XSB bug?
> All the best,
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