[Xsb-development] Re: buglet related to attributed variables

[David W. <wa...@cs...>]

Hi Bart,

Thanks!

Bart Demoen writes:
 > Here is the diagnosis and the cure :-)
 > ...
 > Now the cure: new code for first clause of process_query:
 > 
 > process_query1(X, []) :-        %% no printable variables appeared in the input
 >         !,
 >         call_query(X),
 >         close_open_tables,
 >         dummy,
 >         !,
 >         file_nl(STDFDBK), file_write(STDFDBK, yes), file_nl(STDFDBK),
 >         fail.
 > 
 > and add a dummy definition for the predicate dummy/0:
 > 
 > dummy.

We have an instruction, check_interrupts, which is exactly a WAM call
to true, which is what you have here.  The difficulty is that to
handle interrupts (as XSB does), the WAM must be in a "calling" state,
so it would not easy to add interrupt handling to cut, as you noted.
The intermediate solution would be to add the "handle_interrupts"
instruction before all cuts, though that would be somewhat costly.  I
think for now we'll stay with your solution.

Thanks very much for tracking this down and fixing it for us!

Best regards,
-David