W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > March 2008

Re: RDFa Last Call Comment: Better name than 'instanceof' is needed

From: Micah Dubinko <mdubinko@yahoo-inc.com>
Date: Mon, 17 Mar 2008 21:10:25 -0700
Message-ID: <47DF40B1.3080807@yahoo-inc.com>
To: John Boyer <boyerj@ca.ibm.com>
CC: public-rdf-in-xhtml-tf@w3.org

Food for thought...

If the instanceof attribute were completely removed from RDFa, would any 
use cases be forclosed? Couldn't the same thing be done through rdf:type 
properties on possibly blank nodes?

In discussions about RDFa with non-RDF-familiar people, instanceof has 
been harder for them to grasp.

Thanks,

-m

John Boyer wrote:
>
> RDFa is designed to provide a set of attributes for including RDF 
> information into XHTML documents.
>
> XHTML2 is designed to work with XForms.
>
> Central to the operation of XForms is an "instance", which is a block 
> of XML data over which the XForm operates.  This name for data was 
> obtained from the XML Schema working group as the "standard" way to 
> refer to an occurrence of XML conforming to a given schema as an 
> "instance" of that schema.  In XForms, one can have an instance 
> without physically associating a schema with it, or even having 
> expressed the schema, but that is beside the point as one might 
> reasonably regard such occurrences as an authoring convenience for an 
> implied schema.
>
> The main point is that these things are called "instances" because you 
> can, in principle at least, *instantiate* a template description, much 
> like creating a new object from a class definition.  The XForms 
> instances can, in principle at least and often in practice, be viewed 
> as an instantiation of a template defined by a schema.  In the future, 
> I am hoping we get better at embedding the instantiation operation 
> itself into XForms.
>
> Instantiation does not appear to be what is happening in the case of 
> RDFa.  Instead, the element to which you attach "instanceof" is 
> something to which you simply seem to be attaching some RDF type 
> information.  A name that more accurately reflects that behavior would 
> be preferable.
>
> Lest you think this is just picking a nit, a secondary reason for 
> requesting a change here is that I would like to avoid any confusion 
> between use of the word instance as it applies to XForms versus its 
> use with RDFa.  Although the W3C will not always be able to see name 
> conflicts coming in advance, we should at least take action when we do 
> see a problem coming in advance.  We have been especially charged by 
> W3 management with easing the authoring experience of XHTML and XForms 
> going forward, and I notice to that end that the RDFa attributes are 
> not namespace qualified.  The XForms syntax work being done in XForms 
> 1.2 will likely allow adoption into XHTML without namespace 
> qualification into the XForms namespace.  This eases authoring but 
> accentuates the possibility of confusion when these vocabularies 
> contain similar names, if not exact name conflicts, for different 
> concepts.
>  
> Thank you,
> John M. Boyer, Ph.D.
> Senior Technical Staff Member
> Lotus Forms Architect and Researcher
> Chair, W3C Forms Working Group
> Workplace, Portal and Collaboration Software
> IBM Victoria Software Lab
> E-Mail: boyerj@ca.ibm.com  
>
> Blog: http://www.ibm.com/developerworks/blogs/page/JohnBoyer
> Blog RSS feed: 
> http://www.ibm.com/developerworks/blogs/rss/JohnBoyer?flavor=rssdw
>
Received on Tuesday, 18 March 2008 04:11:58 UTC

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