- From: Dave Reynolds <dave.e.reynolds@googlemail.com>
- Date: Wed, 12 May 2010 11:09:04 +0100
- To: Jos de Bruijn <jos.debruijn@gmail.com>
- CC: Axel Polleres <axel.polleres@deri.org>, Christian De Sainte Marie <csma@fr.ibm.com>, RIF <public-rif-wg@w3.org>
On 12/05/2010 09:36, Jos de Bruijn wrote: > Axel, Christian, all, > > I raised my concerns about the RIF-Core spec in a separate email. > > Concerning facts about class membership: they are both in BLD and PRD > (see [1]). > Concerning class membership atoms in rule conclusions: I do remember > that we explicitly forbade them in Core. That's my recollection too. Our official record of the decision [1] was to allow membership "in Core facts and conditions". We did at one point have an EBNF that reflected that resolution. My memory [2] was that Gary on behalf of the PRD group later pointed that asserting membership facts was just as problematic as concluding them via non ground rules. The problem being that in object-based PR implementations membership is hardwired in the external data model. So we decided to forbid any assertion of membership facts. I.e. the EBNF accurately reflects our intention[3]. The phrasing in section 2.3 is clarified by "they [equality terms and class membership terms] are only allowed in rule premises". I agree that the term rule "premise" is not defined in the document so it could be clearer but I don't see how one could reasonably interpret a ground fact as a "premise". So it seems to me the normative text and informative EBNF are in agreement. Dave [1] http://www.w3.org/2005/rules/wg/track/issues/48 [2] Which I've not been able to validate from the record trail. [3] That intention may be strange and hard to understand but that's the nature of working group compromises :)
Received on Wednesday, 12 May 2010 10:09:42 UTC