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RE: NOT implementing triple stores

From: Christian De Sainte Marie <csma@fr.ibm.com>
Date: Tue, 12 May 2009 14:32:18 +0200
To: "Paul Vincent" <pvincent@tibco.com>
Cc: "RIF WG" <public-rif-wg@w3.org>
Message-ID: <OF99A7E209.A16FA8C7-ONC12575B4.0040A2FD-C12575B4.0044E122@fr.ibm.com>
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</Chair>

Paul,

public-rif-wg-request@w3.org wrote on 11/05/2009 12:30:57:
> 
> I believe the "misquote" mentioned should in fact be the understatement:
> "Gary wants to translate frames to Java objects".
> [...]
> I suggest that the above is (likelihood> 99% IMHO) true regardless of
> Prolog compiler performance...

I completely agree with you. And it is, indeed, an understatement: I guess 
that Gary, like ILOG, does not especially _want_ to translate frames to 
Java objects, but that he has to do it, if he wants to do anything with 
RIF...

I hoped that we would be able to include something more easily translated 
to/from objects in PRD, and maybe even in Core. We did not converge fast 
enough to have it in PRD 1.0 :-(

On the other hand, one might argue that it is better to have PRD 1.0 as a 
basic PR dialect, and to design a full-fledged object-oriented extension 
on top of it (which you have always supported, I think)...

> On frames-objects: "... there are significant semantics/functionality
> differences ..." probably deserves some attention.

One of the main difficulty is to related them (objects and frames), 
although the addition of lists makes it easier: using the usual 
object.field notation to denote the value of an object's field, something 
like the following must hold:

Forall ?o, ?p, ?v, ?o[?p->?v] <=> (?o.?p = ?v or pred:list-contains(?o.?p, 
?v))

(you know that I supported introducing an object specific notation as a 
new form of TERM :-)

<Chair>

But the point raised by Gary is more general than that (I mean, than the 
problem with cardinality etc). 

What one thing that Gary says, I think, is that frames, in their current 
definition, are not syntactic sugar for binary atoms, since you have 
different constraints on the predicate in an atom and a slot in a frame. 
Or, stated another way, that slot names cannot be individuals (e.g. typed 
constants), not anymore than predicates can be individuals.

See also Dave's reply [1] and following thread.

[1] http://lists.w3.org/Archives/Public/public-rif-wg/2009May/0082.html

Cheers,

Christian

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Received on Tuesday, 12 May 2009 12:33:09 GMT

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