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Re: Issues with rif:iri in a number of places in the spec

From: Jos de Bruijn <debruijn@inf.unibz.it>
Date: Thu, 26 Mar 2009 15:55:59 +0100
Message-ID: <49CB977F.3020203@inf.unibz.it>
To: Dave Reynolds <der@hplb.hpl.hp.com>
CC: kifer@cs.sunysb.edu, RIF WG Public list <public-rif-wg@w3.org>


Dave Reynolds wrote:
> Michael Kifer wrote:
>> I discovered several semantic issues with our use of rif:iri in BLD
>> and other
>> docs. The problematic uses are:
>>
>>    1. As ids in the annotations.
>>    2. In the Import directive
>>
>>
>> The problem is that rif:iri constants are not really IRIs, but are
>> uninterpreted constants that can stand for anything. In particular,
>> they can
>> mean different things in different documents. For instance, if some
>> document
>> is identified by a rif:iri constant <foo>, it really means nothing. If I
>> want to refer to that particular document in two other distinct
>> documents, I
>> cannot do that using the rif:iri constant <foo>, as in one document
>> this can be
>> equal 1 and in another to "abc", and in none it has anything to do
>> with the
>> actual IRI foo.
>>
>> The problem with Import is related to that. In addition, in Import we
>> are using
>> rif:iris, but in Base and Prefix IRI strings, which is an arbitrary
>> inconsistency.
>>
>> Solution:
>>
>>   For Import, we could also use IRI strings, but this is not the
>> solution that
>>   I favor. I prefer to use something like anyIRI. I don't know if this
>> data
>>   type exists (could not find it), but we can define it as rif:anyIRI.
> 
> It does exist - xsd:anyURI. In XML Schema 1.0 this denotes URIs but in
> XML Schema 1.1 it is extended to IRIs.
> 
>>   rif:anyIRI constants would be interpreted by unicode strings that
>> have the
>>   form of an IRI (in contrast to rif:iri's, which can be interpreted by
>>   anything in the domain).
>>   Once we have that, I would propose to change the iri strings in
>> Base, Prefix,
>>   and Import to use rif:anyIRI (or whatever we decide to name it).
> 
> Using xsd:anyURI possibly makes sense for imports.

Possibly, but I'm not convinced.  Why not simply write IRIs?  Why use
constants here at all?

> 
> I don't think it works for annotations.
> 
> Surely the point of the annotations is that they denote the rule (or
> rule fragment) being annotated not a particular physical document
> location. It just a useful convention to reuse a location IRI, when it
> exists, for that denotation but there is no formal requirement for this.
> Which is precisely what a rif:iri is appropriate here.
> 
> Another way of saying the same thing ...
> I want to interpret the rule annotations as RDF metadata. The subject of
> those metadata statements is not a document or the address of a document
> it is a rule denoted by some arbitrary IRI. Whereas if the Rule IDs were
> changed to xsd:anyURI then the rule metadata would say things like:
> 
>   "http://example.com/rule1"^^xsd:anyURI  dc:author "Dave Reynolds".
> 
> which is not what is intended (and not legal RDF of course). It is not
> interesting that I might have authored that URI string, what is
> interesting is that I authored the rule which I was trying to denote by
> such a URI.
> 
> If you also wanted metadata that refers to documents, such as a place
> where you can download the original rule source then that would indeed
> be an anyURI, for example:
> 
>    http://example.com/rule1
>           dc:author "Dave Reynolds";
>           eg:originalSource
>                 "http://dave.reynolds.net/myRules/rule1"^^xsd:anyURI .
> 
> Of course annotations have no semantic interpretation within RIF so we
> can do what we want but this use of rif:iri seems reasonable.

Agreed.
But I think I would also not be opposed to simply writing IRIs here
(rather than IRI constants). I do not have a preference either way.


Best, Jos

> 
>> I further propose to extend our Curie notation to support
>> rif:anyIRI constants. Maybe use <foo:bar> for rif:iri's and foo:bar for
>> rif:anyIRI's.
> 
> That particular notation would have confusing conflicts with the other
> specs that use Curie-like notation but I'm sure a syntax could be
> devised if needed.
> 
> Dave
> 

-- 
+43 1 58801 18470        debruijn@inf.unibz.it

Jos de Bruijn,        http://www.debruijn.net/
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Received on Thursday, 26 March 2009 14:57:02 GMT

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