- From: <jos.deroo@agfa.com>
- Date: Sun, 17 Dec 2006 21:29:32 +0100
- To: sandro@w3.org
- Cc: "Gary Hallmark" <gary.hallmark@oracle.com>, kifer@cs.sunysb.edu (Michael Kifer), "W3C RIF WG" <public-rif-wg@w3.org>, public-rif-wg-request@w3.org, "Paul Vincent" <pvincent@tibco.com>
>>> At the moment, unless some new information comes along, I'm inclined
to
>>> agree that we need to leave recursive Horn rules out of the core.
>>
>> All of the rule sets that I use for my practical work have
>> some rules that are recursive, even some of them also have
>> mutual predicate dependency like
>> pred3(X,Z):- pred1(X,Y), pred2(Y,Z).
>> pred2(X,Z):- pred3(X,Y), pred4(Y,Z).
>
> I suspect all "power users" of rule systems use recursive rules and
> would need to use a more powerful dialect than RIF Core.
Well, depends, but I consider working with e.g. rdf collections
to find member items not really "power use"..
{?LIST rdf:first ?ITEM} => {?ITEM list:in ?LIST}.
{?LIST rdf:rest ?REST. ?ITEM list:in ?REST} => {?ITEM list:in ?LIST}.
nor examples like
{?X eg:ancestor ?Y} => {?Y eg:descendant ?X}.
{?X eg:descendant ?Y} => {?Y eg:ancestor ?X}.
{?X eg:ancestor ?Y. ?Y eg:ancestor ?Z} => {?X eg:ancestor ?Z}.
--
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Sunday, 17 December 2006 20:30:27 UTC