Re: role vs. arcrole

Hi Elliotte-- There's an easy answer to your very reasonable question: 
simple links can't have both an arc role and a role for their remote 
resource if we don't have two separate attribute names.  We agreed to allow 
arc roles on simple links so that they would not be discriminated against 
in RDF mapping.  We narrowly escaped another naming complexity by agreeing 
(actually, this was an agreement of long standing) that a simple link's 
*local* resource doesn't get to say what role it has.

         Eve

At 07:02 PM 7/10/00 -0700, Elliotte Rusty Harold wrote:
>The July 3 XLink candidate recommendation introduces a new arcrole
>attribute for arc type elements only, and it forbids the normal role
>attribute on arc elements.
>
>However, there really isn't that much difference between role and
>arcrole, in fact absolutely nothing as far as an XLink processor is
>concerned, so I'm wondering why the two separate attributes?  Both role
>and arcrole must contain URIs (though parsers aren;t required to enforce
>this). In both cases, the details of how or whether or when an XLink
>processor will follow the URI in a role or an arcrole is application
>dependent, as is the interpretation of what it does with the document it
>finds at that URI.
>
>The only difference I can find between role and arcrole is that the
>document at the role URI describes the element whose role it is in some
>general sense, whereas the document at the arcrole URI should
>(unenforceably) describe the relationship between the two sides of the
>arc (e.g. parent-child, employer-employee, etc.).  No details are
>provided for what the syntax of these documents should be or how
>applications should handle them.
>
>Given everything that's unspecified I don't see the importance of
>distinguishing these two attributes. I propose making XLink simpler by
>deleting arcrole and allowing role attributes on arc elements. A
>suggestion as to what the role of an arc element should be can still be
>provided, but I see no justification for two separate attributes here.

--
Eve Maler                                    +1 781 442 3190
Sun Microsystems XML Technology Center    elm @ east.sun.com

Received on Tuesday, 11 July 2000 10:40:11 UTC