Re: Datalog (DLV) question
From: <andrew_at_acooke.org>
Date: 26 Dec 2006 08:50:23 -0800
Message-ID: <1167151823.912938.135860_at_79g2000cws.googlegroups.com>
Date: 26 Dec 2006 08:50:23 -0800
Message-ID: <1167151823.912938.135860_at_79g2000cws.googlegroups.com>
Tying loose ends....
In the negated clause in my constraint I had used "_" without giving it any thought. But all variables in a negated clause need to be bound (at first this struck me as odd, but I believe it's because otherwise "you" are pretty much free to choose "_" so that the constraint fails, which makes it pointless).
The fix is trivial - pull out the field of interest via a separate clause, so that no "_" is needed.
Thanks to Wolfgang Faber, one of the DLV developers, who took the time
to explain this over email.
Andrew
Received on Tue Dec 26 2006 - 17:50:23 CET