- From: Carlos Buil Aranda <cbuil@fi.upm.es>
- Date: Tue, 19 Jul 2011 22:53:55 -0400
- To: Gregory Williams <greg@evilfunhouse.com>
- Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
- Message-ID: <CABdcz9H2x0rqTq7o5tHdDov0=N7JPvKMnzBYQoiouHYLh1sGsA@mail.gmail.com>
any more opinions on that? thanks, Carlos 2011/7/19 Gregory Williams <greg@evilfunhouse.com> > On Jul 19, 2011, at 5:02 PM, Carlos Buil Aranda wrote: > > > just summarizing a bit, the main concern is the use of variables in > SERVICE. The problem relies in the specification of the semantics and the > boundedness condition which suggests an order for executing the query. The > problem is first, the way of defining the execution of SERVICE VAR, which > using the current join semantics is wrong because it is not possible to > evaluate Join(G, Service(VAR, G, Transform(P), SilentOp)) because VAR still > hasn't a value. Following this, the boundedness condition, which has to be > completed for all the SPARQL 1.1 operators. Am I right? > > Thanks Carlos. Yes, I think this is a good summary of the biggest issues. > > > So, the possible solutions are: > > - For the SERVICE VAR semantics > > - add a new operation that could allow the evaluation (operation which > wouldn't be bottom-up) > > - define its whole semantics in a new way > > - For the boundedness restriction > > - specify all cases: it may take a bit long > > - remove it? I do not think this is a good idea, how do we specify then > that a variable is bound (which is needed for the evaluation semantics of > SERVICE VAR)? > > It might be needed for the evaluation semantics, but I don't think the > current text connects the two. There is no mention of strongly bounded > variables or service safeness in the "Definition: Evaluation of a Service > Pattern" section. > > thanks, > .greg > > >
Received on Wednesday, 20 July 2011 02:54:42 UTC