- From: <elharo@metalab.unc.edu>
- Date: Mon, 8 Oct 2007 02:11:05 -0500
- To: public-xhtml2@w3.org
- CC: xhtml2-issues@mn.aptest.com
There's a a deep and serious problem with section 4.1, Extending the collection of roles. This section states: It is possible to define additional role values. Such values MUST be defined in their own namespace. We've been down this road before in other specs such as XPointer, W3C Schemas and XPath. There is nothing in the Namespaces spec that in any way indicates that a qualified name may apear in an attribute value. There is no standard way to indicate the namespace mappings in scope for an attribute *value* as distinct from an attribute *name*. 1. If it it is your intention that such values inherit the namespace bindings of their parent element, this must be explicitly stated. There is nothing in the namespaces spec to indicate that applications can apply namespace bindings to attribute values. 2. This approach only works if these values only appear in an actual XHTML document. If it is ever the intention to use such role values outside of XHTML (or some XML-host language) you're hosed. XPath and XPointer both foundered on these shoals. 3. Even if the role attribute value only has meaning within an XML host language, embedding QNames in attribute values is still a pragmatically bad idea. We have almost ten years of experience with multiple specifications to prove that QNames in attribute values confuse users and complexify implementations. Please find another way to achieve your worthy goals without depending on namespace prefix resolution in attribute values. I suggest simply abandoning the CURIE mechanism and making the role values full, absolute URIs. Unlike XPath, there really isn't a compelling reason for an abbreviated syntax here. There'll usually only be one of these on any given element. It's more like an href attribute than anything else. People have no trouble using full URIs in those when appropriate. -- Elliotte Rusty Harold elharo@metalab.unc.edu Java I/O 2nd Edition Just Published! http://www.cafeaulait.org/books/javaio2/ http://www.amazon.com/exec/obidos/ISBN=0596527500/ref=nosim/cafeaulaitA/
Received on Monday, 8 October 2007 07:13:15 UTC