Re: ISSUE-77 (xsd-c14n): XSD canonicalization 1.0 or 1.1? [R2RML]

Richard, all,

We do have precedence here. Both the OWL and the RIF WG-s hit exactly the same issue (I have not checked lately for SPARQL and I imagine the RDF WG will hit the same problem, too). Here is what has happened in the OWL 2case (the RIF is fairly identical).

- OWL 2 has clearly chosen for XSD 1.1. That means the reference in the document _is_ on the XSD 1.1 CR document. Unusual, slight breakage of the rules, but it was necessary.
- The 'Status' section of the Recommendation includes a subsection on this, see the example below
- Once the Recommendations were published, the OWL 2 WG went into a 'dormant' state. Ie, it is not formally closed, is maintained in the books, but there is not activity (calls, etc). The only exception is that error reports are stored and maintained in a file; something that this group will have to plan for when the time comes anyway.
- The agreement is that once the XSD 1.1 is published as Rec, the Group reconvenes and publishes what we call an Edited Recommendation. That is a rec that has absolutely non difference in technical content v.a.v. the original ones, but only editorial changes (misspellings, that sort of things). In this specific case that ER of OWL 2 will change the formal reference to the XSD 1.1 Rec, remove that status subsection and, if any, fold in the editorial errors that the community may have found. Ie, there would be an editorial work to be done when the time comes, and editorial work that is clearly quick and can be done by 1-2 persons.

The OWL 2 adoption has not suffered from this issue at all, nobody raised any problems since 2009. My advise would be to adopt the same line of action for R2RML and DM. It would be wrong to keep to 1.0 when other SW standards have made the choice of 1.1



Here is the status subsection I was referring to:

XML Schema Datatypes Dependency

OWL 2 is defined to use datatypes defined in the XML Schema Definition Language (XSD). As of this writing, the latest W3C Recommendation for XSD is version 1.0, with version 1.1 progressing toward Recommendation. OWL 2 has been designed to take advantage of the new datatypes and clearer explanations available in XSD 1.1, but for now those advantages are being partially put on hold. Specifically, until XSD 1.1 becomes a W3C Recommendation, the elements of OWL 2 which are based on it should be considered optional, as detailed in Conformance, section 2.3. Upon the publication of XSD 1.1 as a W3C Recommendation, those elements cease to be optional and are to be considered required as otherwise specified.

We suggest that for now developers and users follow the XSD 1.1 Candidate Recommendation. Based on discussions between the Schema and OWL Working Groups, we do not expect any implementation changes will be necessary as XSD 1.1 advances to Recommendation.


On Nov 25, 2011, at 24:30 , RDB2RDF Working Group Issue Tracker wrote:

> ISSUE-77 (xsd-c14n): XSD canonicalization  1.0 or 1.1? [R2RML]
> Raised by: Richard Cyganiak
> On product: R2RML
> So it turns out that XSD canonicalization is actually very different between XSD 1.0 and XSD 1.1. Quite a lot has changed  I don't have the full picture but handling of time zone offsets is different, handling of decimals appears to be different, and who knows what else.
> Given that XSD 1.1 is in the CR stage, I don't feel very good about writing spec text that asks R2RML/DM implementers to implement XSD 1.0 canonicalization rules that will soon be obsolete.
> On the other hand, given that XSD 1.1 is not yet at REC stage, we can't write spec text that normatively prescribes the use of XSD 1.1 canonicalization rules.

Ivan Herman, W3C Semantic Web Activity Lead
mobile: +31-641044153

Received on Friday, 25 November 2011 08:21:43 UTC