Re: [RIF] Extensible Design

From: "Gerd Wagner" <wagnerg@tu-cottbus.de>
Subject: RE: [RIF] Extensible Design 
Date: Thu, 4 May 2006 22:31:55 +0200

> > > Hopefully there can be many modules shared between 
> > > dialects, where both the syntax and semantics are 
> > > shared. I'm not sure if it'll ever make sense to share 
> > > syntax but not semantics for some part of a language.
> > 
> > Well, it seems to me that the proposal by Boley et al 
> > advocates precisely this view. My reading of the 
> > proposal is that several (perhaps many) RIF dialects 
> > will share the same syntax (or very similar syntaxes) 
> > for conditions but will diverge on semantics.
> 
> Let me try to elaborate on this observation:
> 
> 1) The RIF family will consist of several branches
> of dialects, most of which overlap in their condition
> language. 

It seems to me that the most likely commonality between branches will be
just conjunctions of function-free atomic predications, i.e., quite a small
part of even the base condition language in the proposal.

> Each branch will have a core, which
> defines the common syntax and semantics of the branch.

It seems to me that again that this core is likely to be just 
conjunctions of function-free atomic predications for most branches.

> Extensions of this core define additional syntax and
> semantics.

Sure - this makes them extensions.

> 2) Most RIF dialects will not only share the syntax
> but also the semantics of conditions (except for
> normative/integrity rules, which do, in general, not 
> have conditions).

In the current proposal this does not appear to be true.  In the current
proposal differences in the semantics of positive conditions appear between
FOL and LP and even within LP.

> 3) Data literals, object names, function symbols
> and predicate symbols may be typed. Using suitable
> predicate/atom types, this allows to represent RDF 
> and OWL rules directly (and not only via a "query 
> interface").

I don't see this anywhere in the proposal.

> -Gerd

Peter F. Patel-Schneider

Received on Saturday, 6 May 2006 12:18:13 UTC