W3C home > Mailing lists > Public > semantic-web@w3.org > April 2008

Re: New RIF drafts

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Wed, 16 Apr 2008 08:28:43 -0400
To: Steve Harris <swh@ecs.soton.ac.uk>
Cc: Sandro Hawke <sandro@w3.org>, semantic-web@w3.org, www-rdf-rules@w3.org
Message-ID: <30080.1208348923@cs.sunysb.edu>


Steve Harris <swh@ecs.soton.ac.uk> writes:
> 
> On 15 Apr 2008, at 18:07, Sandro Hawke wrote:
> >
> >
> > We have some new drafts from the Rule Interchange Format (RIF) Working
> > Group.  While the group is not targeted at producing a "Semantic Web
> > Rule Language", its output will cover much of the same space.  I  
> > suggest
> > anyone interested in rule languages (especially from a web  
> > perspective)
> > take a look at what RIF is doing and send comments:
> >
> > http://www.w3.org/TR/rif-bld/   (our first RIF dialect, Horn with  
> > Equality)
> > http://www.w3.org/TR/rif-fld/   (framework for more logic dialects)
> > http://www.w3.org/TR/rif-rdf-owl/  (how to use BLD with RDF, OWL-DL,  
> > OWL-Full)
> 
> I'm more-or-less ignorant of the technical issues here, but at a  
> surface level the presentation syntax given in example 2 of the FLD  
> appears to have some arbitrary differences from SPARQL, eg the use of
>     abbr expands into uri
> instead of
>     PREFIX abbr: <uri>

Steve,
Whether you are ignorant of the technical issues or not is beside the point.
The point is that both the FLD and BLD documents clearly state (several
times, including right above the first example where this notation is used)
that compact URI notation is NOT part of the syntax, but a shorthand used
to avoid writing long strings. The "expands to" is not syntax, but plain
English. It is even in a different font and in a separate block of text.

> and the use of ()s for grouping, as opposed to {}s, and some of the  
> operators being prefix and some being infix.

It would have been helpful if you were a bit more specific, but you should
understand that FLD is a logic framework, and it uses notation typically
found in any logic textbook. FLD's (and BLD's) presentation syntax is
abstract syntax designed to describe the formal semantics. This
presentation syntax is missing several important aspects of a concrete
language -- on purpose. This nature of the syntax is stressed at least twice
in each document. The concrete language is XML.

In contrast, SPARQL is a concrete language, and it is not even a logic
language.

> There may well be cultural reasons for this syntax, but I expect many  
> people to want to work with both syntaxes, and some commonality might  
> be helpful in reducing the learning curve.

If you got that far and understood it then I doubt it very much that the
PREFIX issue is a stumbling block.


	cheers
	  --michael  
Received on Wednesday, 16 April 2008 12:29:33 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 1 March 2016 07:42:04 UTC