- From: Christian De Sainte Marie <csma@fr.ibm.com>
- Date: Wed, 12 May 2010 13:17:48 +0200
- To: Jos de Bruijn <jos.debruijn@gmail.com>
- Cc: RIF <public-rif-wg@w3.org>
- Message-ID: <OF21F5787D.D4EE5B13-ONC1257721.003D32E5-C1257721.003E0EFA@fr.ibm.com>
Hi Jos, Jos wrote on 12/05/2010 11:01:05: > > I found a strange discrepancy in PRD. In the definition of assert > fact actions [1], it is possible to assert class membership facts. > Now, I understand that there is a shortcut syntax for asserts in the > XML [2] and presentation [3] syntaxes. In particular, it's not > necessary to write the "Assert" for positional and frame atoms. > However, if one wants to assert a class membership formula, one is > required to write the "Assert". > Why is there this discrepancy? Was that an oversight? The reason is that the "Assert-free" syntax is the recommended syntax for PRD rules that are also Core. But the assertion of a class membership is allowed, in PRD, only for newly created instances, that is, inside a Do, and after an action variable has been bound using the New construct [1]: in other words, a PRD rule that asserts a class membership cannot be Core, and the "Assert-free" syntax would not make sense in that case (even for positional atoms and frames, the "Assert-free" syntax is not allowed inside a Do). [1]http://www.w3.org/TR/rif-prd/#def-wf-action-block Cheers, Christian IBM 9 rue de Verdun 94253 - Gentilly cedex - FRANCE Tel. +33 1 49 08 35 00 Fax +33 1 49 08 35 10 Sauf indication contraire ci-dessus:/ Unless stated otherwise above: Compagnie IBM France Siege Social : 17 avenue de l'Europe, 92275 Bois-Colombes Cedex RCS Nanterre 552 118 465 Forme Sociale : S.A.S. Capital Social : 611.451.766,20 ? SIREN/SIRET : 552 118 465 03644
Received on Wednesday, 12 May 2010 11:18:26 UTC