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Re: Closing ISSUE-13

From: Ivan Herman <ivan@w3.org>
Date: Thu, 10 May 2012 15:04:37 +0200
Cc: Arnaud Le Hors <lehors@us.ibm.com>, David Wood <david@3roundstones.com>, public-rdf-wg Group WG <public-rdf-wg@w3.org>
Message-Id: <C38963C3-960F-4776-B46F-20A4E8B12920@w3.org>
To: Richard Cyganiak <richard@cyganiak.de>
Richard,

- A.isEqualNode(B)[1] compares the notes A and B _and_ its children. Ie, it compares, among other things, the nodeName of the two document fragments
- the LV mapping returns the result of the following transforms on L (lexical value)
  wrap L into _something_ -> xmldoc -> domdoc -> domfrag -> normalize()  

So I can be evil enough and wrap a lexical value into a _different_ XML element before doing the rest of the transformation for each lexical value. As a result, the values will always be different under the value space comparison.

It is obviously a stupid and pathological case, but the exact wording of the algorithm does not exclude that...

Ivan


[1] http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-isEqualNode

On May 10, 2012, at 14:27 , Richard Cyganiak wrote:

> Ivan,
> 
> On 10 May 2012, at 09:11, Ivan Herman wrote:
>> (First of all, I explicitly cc this to Arnaud; he was one of the co-editors of the DOM3 spec, it would be good if he could review that to be on the safe side...)
> 
> +1!
> 
>> the only thing I am uncertain about is that issue about the arbitrary XML tag enclosing the whole thing. We clearly need that, but how does that exactly affect the algorithm?
> 
> The thing with the arbitrary enclosing start and end tag was taken straight from RDF 2004. It's in the definition of the lexical space.
> 
>> After all, A.isEqualNode(B) compares the nodes' names; if different arbitrary enclosing terms are used, then this will return False, although our intention is to say True...
> 
> But A.isEqualNode(B) compares the *values*, and the values are the result of applying the L2V mapping, and the L2V mapping returns only the *child nodes* of the document element. So the arbitrary element that we created is *not* being compared; only the list of its children is compared.
> 
>> Somehow the lexical-to-value mapping algorithm has to keep track, when creating xmldoc, whether such a wrapper element has been added to the original literal or not.
> 
> I'm not sure what you mean. If the original literal already is properly wrapped in matching start and end tags (that is, it's already a well-formed XML document, not just an XML fragment), then the phrasing as is just wraps it into another element. Everything should still work.
>> 
>> I am not sure what the best way of handling that is. Maybe, conceptually, that top level wrapping element is a predefined RDF element, and must be used only when there is no wrapping element in the original lexical form in the first place.
> 
> I'm not sure what problem this would solve.
> 
>> (In any case, this is not something the author of the RDF content should see.)
> 
> They don't.
> 
> Best,
> Richard
> 
> 
> 
>> 
>> Ivan 
>> 
>> 
>> 
>> On May 9, 2012, at 20:12 , Richard Cyganiak wrote:
>> 
>>> Dave, all,
>>> 
>>> I have updated the RDF Concepts ED according to today's resolution. Please review.
>>> 
>>> http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html#section-XMLLiteral
>>> 
>>> RDF Semantics still needs to be updated accordingly (make rdf:XMLLiteral optional and interpret it only under D-Entailment, like any other datatype).
>>> 
>>> I've taken the liberty to create an action (on a randomly chosen RDF Semantics editor):
>>> 
>>> https://www.w3.org/2011/rdf-wg/track/actions/170
>>> 
>>> No objection to the status change.
>>> 
>>> Best,
>>> Richard
>>> 
>>> 
>>> 
>>> On 9 May 2012, at 17:45, David Wood wrote:
>>> 
>>>> Hi all,
>>>> 
>>>> Today, we resolved [1]:
>>>> [[
>>>> RESOLVED: in RDF 1.1: [a] XMLLiterals are optional; [b] lexical space consists of well-formed XML fragments; [c] the canonical lexical form is http://www.w3.org/TR/xml-exc-c14n/, as defined in RDF 2004; [d] the value space consists of (normalized) DOM trees.
>>>> ]]
>>>> 
>>>> Richard's proposal [2], that evolved into this resolution, was meant to close ISSUE-13 [3].  So, I have changed the status of ISSUE-13 to "pending approval" and suggest that the implementation of this resolution be considered editorial in nature.
>>>> 
>>>> Any objections?
>>>> 
>>>> Regards,
>>>> Dave
>>>> 
>>>> [1] http://www.w3.org/2011/rdf-wg/meeting/2012-05-09#resolution_1
>>>> [2] http://lists.w3.org/Archives/Public/public-rdf-wg/2012May/0006.html
>>>> [3] https://www.w3.org/2011/rdf-wg/track/issues/13
>>>> 
>>>> 
>>>> 
>>> 
>>> 
>> 
>> 
>> ----
>> Ivan Herman, W3C Semantic Web Activity Lead
>> Home: http://www.w3.org/People/Ivan/
>> mobile: +31-641044153
>> FOAF: http://www.ivan-herman.net/foaf.rdf
>> 
>> 
>> 
>> 
>> 
>> 
> 
> 


----
Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
FOAF: http://www.ivan-herman.net/foaf.rdf
Received on Thursday, 10 May 2012 13:01:48 GMT

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