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Re: namespace prefix definitions in presentation syntax

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Fri, 29 Feb 2008 14:43:14 -0500
To: axel@polleres.net
Cc: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>
Message-ID: <17574.1204314194@cs.sunysb.edu>


> 
> Michael Kifer wrote:
> > The RIF specification says that curies are NOT to be used in XML
> 
> Sure, in XML syntax I can use the "regular" namespace mechanism of XML. 
> no problem, I know how to do this.

Note that curies are NOT namespaces. They are just a macro mechanism, which
is not a standard in XML.


> > only
> > absolute URIs. In the presentation syntax they are used as an informal
> > shorthand.
> 
> So, if I understand this correctly -  that there are no curies in the 
> presentation syntax - then what I just suggest is just to formalize the 
> informal shorthand use in RIF presentation syntax a bit, by adopting one 
> of the ways other standards define it... shouldn't cause major trouble, 
> or no? I am having major pain writing down examples otherwise...

The presentation syntax is not a parseable syntax anyway. Many things have
been left unspecified, including delimiters etc. At attempt to give a
standard syntax to curies will create a wrong impression that they are part
of the syntax, while they are not. For instance, when is a curie a curie?
In what contexts should a:b be expanded? Into what exactly should it be
expanded?  For instance, in "xsd:string"^^rif:iri and
"xsd:string"^^xsd:string, what is to be expanded and what not?

If you start formalizing the curies you would have to go over all that
stuff and will get bogged down with the other details of the syntax. This
is precisely what we do not want to do now.

At the same time, I am not against developing a normative RIF presentation
syntax. If we decide to do this (there were numerous objections to this in
the past), then a separate task force could do this. However, i do not
think we should be doing this now --- too much unfinished work hanging over
this group.


	--michael  


> best,
> Axel
> 
> 
> > 	--michael  
> > 
> >> Dear all,
> >>
> >> I just tried to write down some RIF presentation syntax... (I know I 
> >> shouldn't do this) ... and realized that we don't have any way to define 
> >> namespace prefixes there although we use curies allover...
> > 
> >> So I thought we shall reuse one of the established syntaxes here instead 
> >> of reinventing the wheel.
> >>
> >> 3 alternatives come to my mind:
> >>
> >> TURTLE:
> >>
> >> @prefix prefix: <IRI>.
> >>
> >> SPARQL:
> >>
> >> PREFIX prefix: <IRI>
> >>
> >> XQuery:
> >>
> >> declare namespace prefix="IRI"
> >>
> >> for the moment, I suggest to us the latter, because
> >> we never use angle bracketted IRI's  in the document.
> >>
> >> BTW: We might want to switch to angle brackets in the end, because
> >> with curies alone, we cannot express all URIs (that is acxtually a 
> >> severe problem in RDF/XML, btw, where properties can only be CURIEs)
> >>
> >>   e.g. assume I have a datatype "http://mydatatype.com/"
> >>
> >> I cannot write:
> >>
> >>    "12345"^^http://mydatatype.com/
> >>
> >> because we have only CURIEs in the datatype position (didn't see other 
> >> examples so far) and the pain thing is that http://mydatatype.com/ 
> >> cannot really be synbtactically be split into a QName.
> >>
> >> obviously, we don't want to end up in
> >>
> >>    "12345"^^"http://mydatatype.com/"^^rif:iri
> >>
> >> which BTW could then be written as:
> >>
> >>    "12345"^^"htttp://mydatatype.com/"^^"http://theIRIforRifIRI"^^rif:iri
> >>
> >> which actually could be written as:
> >>  
> >> "12345"^^"ttp://mydatatype.com/"^^"http://theIRIforRifIRI"^^"http://theIRIforRifIRI"^^rif:iri
> >>
> >> ...
> >>
> >> right?
> >>
> >> Axel
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> -- 
> >> Dr. Axel Polleres
> >> email: axel@polleres.net  url: http://www.polleres.net/
> >>
> >> rdfs:Resource owl:differentFrom xsd:anyURI .
> >>
> >>
> > 
> > 
> 
> 
> -- 
> Dr. Axel Polleres
> email: axel@polleres.net  url: http://www.polleres.net/
> 
> rdfs:Resource owl:differentFrom xsd:anyURI .
> 
> 
Received on Friday, 29 February 2008 19:45:35 GMT

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