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Re: namespace prefix definitions in presentation syntax

From: Axel Polleres <axel.polleres@deri.org>
Date: Fri, 29 Feb 2008 20:12:00 +0000
Message-ID: <47C86710.5090403@deri.org>
To: Michael Kifer <kifer@cs.sunysb.edu>
CC: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>

Michael Kifer wrote:
>> 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.

This is something I could live with (RDF/XML does as well... I mean not 
that I want to out myself as big RDF/XML fan but that particular aspect 
I personally could live with.)

>>> 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.

Ok, I see.

> 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.

Hmmm, just thought this was an easy issue which we could resolve 
quickly, but point taken.

Axel

> 	--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 .
>>
>>
> 
> 
> 


-- 
Dr. Axel Polleres
email: axel@polleres.net  url: http://www.polleres.net/

rdfs:Resource owl:differentFrom xsd:anyURI .
Received on Friday, 29 February 2008 20:12:26 GMT

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