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Re: Grammar for PREFIX definitions

From: David Booth <david@dbooth.org>
Date: Wed, 14 Dec 2011 14:09:28 -0500
To: Axel Polleres <axel.polleres@deri.org>
Cc: public-rdf-dawg-comments@w3.org
Message-ID: <1323889768.9602.62683.camel@dbooth-laptop>
Thank you.  I am satisfied with this resolution.

David


On Wed, 2011-12-14 at 18:46 +0100, Axel Polleres wrote:
> Dear David,
> 
> This is in response to
> http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2011Sep/0004.html
> 
> Though an interesting proposal, the WG has after discussion come to
> the conclusion that the addition of an additional feature like that is
> too late in the process of our group and thus beyond our current
> charter. 
> 
> Please also note that such prefix handling is not foreseen in the
> current Turtle proposal worked on by the RDF1.1 working group [1]. 
> 
> Anyways, like other features that weren't selected in this current
> standardisation round of SPARQL1.1, if the feature experiences
> adoptions in implemented systems, it might be subject to future
> evolutions of the standard. The working group is capturing points as
> input for any future chartering process.
> 
>    http://www.w3.org/2009/sparql/wiki/Future_Work_Items 
> 
> We would be grateful if you would acknowledge that your comment has
> been answered by sending a reply to this mailing list.
> 
> best regards,
> Axel, on behalf of the SPARQL Working group
> 
> 1. http://www.w3.org/2010/01/Turtle/#sec-grammar-grammar
> 
> 
> ---- Original message ---
> It would be helpful to allow a prefix to be defined in terms of a
> previously defined prefix, so that one could write a query like this:
> 
>   PREFIX testingGraph: <http://example/non-intuitive-URI/g147x2>
>   PREFIX productionGraph: <http://example/non-intuitive-URI/g42m11>
>   PREFIX graphToUse: testingGraph:
> 
>   INSERT ... GRAPH graphToUse: { ... }
>   WHERE ... GRAPH graphToUse: { ... }
> 
> This way, to change the query from test to production use, one only
> needs to change one prefix definition, and it is still very mnemonic:
> 
>   PREFIX graphToUse: productionGraph:
> 
> Without this ability, one would instead have to write something like the
> following, which is far less mnemonic (because URIs are often not very
> intuitive):
> 
>   PREFIX graphToUse: <http://example/non-intuitive-URI/g42m11>
> 
> 
> This ability would also enable groups of related graph names to be
> managed a little easier.  For example, a query might use three input
> graphs and produce one output graph:
> 
>   PREFIX testBase: <http://example/test-URI-base/>
>   PREFIX productionBase: <http://example/production-URI-base/>
>   PREFIX graphBase: testBase:
> 
> 
>   INSERT ... GRAPH graphBase:output { ... }
>   WHERE ... GRAPH graphBase:input1 { ... }
>         ... GRAPH graphBase:input2 { ... }
>         ... GRAPH graphBase:input3 { ... }
> 
> 
> However, at present the grammar for PREFIX definitions does not permit a
> prefix to be defined in terms of a previously defined prefix: 
> http://www.w3.org/TR/sparql11-query/#rPrefixDecl 
> 
>   [6]  PrefixDecl  ::=  'PREFIX' PNAME_NS IRI_REF
> 
> I suggest changing grammar rule 6 to:
> 
>   [6]  PrefixDecl  ::=  'PREFIX' PNAME_NS IRIref
> 
> This would allow the prefix to be defined in terms of either an IRI_REF
> or a PrefixedName, per rule 125:
> 
>   [125]  IRIref	  ::=  	IRI_REF | PrefixedName
> 
> 
> 
> If the working group decides not to include this ability in SPARQL 1.1
> (especially given how late this comment is arriving) then please put it
> on a wish list for a future version.
> 
> Thanks!
> 
> 

-- 
David Booth, Ph.D.
http://dbooth.org/

Opinions expressed herein are those of the author and do not necessarily
reflect those of his employer.
Received on Wednesday, 14 December 2011 19:16:42 GMT

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