[PPL-devel] Arithmetic evaluation bug in the CVS HEAD version of XSB

[Roberto Bagnara]

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).
> end_of_file.
> [user compiled, cpu time used: 0.0090 seconds]
> [user loaded]
> 
> | ?- side_step_term_as_arithmetic_argument_bug(1+1+1,N).
> 
> N = 3;
> 
> no
> | ?-
> 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,

     Roberto

-- 
Prof. Roberto Bagnara
Computer Science Group
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara at cs.unipr.it