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Re: PROV-ISSUE-589: scope of prefixes in prov-n documents [prov-n]

From: James Cheney <jcheney@inf.ed.ac.uk>
Date: Thu, 1 Nov 2012 17:02:14 +0000
Message-Id: <22C1BC8A-B283-42AD-9D6F-032ADF0ECB76@inf.ed.ac.uk>
To: Provenance Working Group <public-prov-wg@w3.org>
Hi,

Just to clarify: There is some mention in the discussion of issue-496 that the "excluding" scoping rule (where bundles must be self-contained) helps simplify prov-constraints.  I think they are orthogonal issues, since prov-constraints implicitly assumes that co-reference has been resolved before we start checking validity and so on.  

I think it is useful to illustrate the effect of the resolution today on a simple example:

document
  prefix ex http://www.example.com
  bundle ex:b1
    entity(ex:e1)
  endBundle
  bundle ex:b2
    prefix ex http://www.example2.com
    entity(ex:e1)
  endBundle
endDocument

With the excluding semantics, every bundle has to be self-contained, and so the example above is *illegal* in prov-n with "excluding" scoping, because b1 doesn't (re)declare namespace ex.

After today's resolution, the above document is *legal*, provided we are clear that redeclarations at inner scopes are allowed and take precedence over any prior declarations.

However, either way it is irrelevant to prov-constraints, which doesn't say anything about namespaces; implementations need to expand out prefixes in the usual way first.  The above document (if legal) is really shorthand for 

document
  bundle http://www.example.com/#b1
    entity(http://www.example.com/#e1)
  endBundle
  bundle http://www.example.com/#b2
    entity(http://www.example2.com/e1)
  endBundle
endDocument

thus, avoiding the potential name clash between the two ex:e1's.

Perhaps this should be clarified in prov-n, prov-constraints, or both.

--James

On Nov 1, 2012, at 4:42 PM, Provenance Working Group Issue Tracker wrote:

> PROV-ISSUE-589: scope of prefixes in prov-n documents [prov-n]
> 
> http://www.w3.org/2011/prov/track/issues/589
> 
> Raised by: Luc Moreau
> On product: prov-n
> 
> 
> 
> Change the scope of document prefixes in prov-n to include inner bundles (unless they are re-declared).
> 
> This is a follow-up of ISSUE-496
> 
> See http://www.w3.org/2011/prov/meeting/2012-11-01#resolution_5
> 
> 
> 
> 
> 
> 


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Received on Thursday, 1 November 2012 17:02:45 GMT

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