No requirement for XML Base support = no interoperability!

As far as I can tell, XML Base is a technology that is "available, but
there's no requirement for tools to support it".  

For example, with XML Schemas you can use a relative URL in
schemaLocation, with xml:base providing the base URL:

  <BookCatalogue xml:base="http://www.example.org"
                 schemaLocation="BookCatalogue.xsd"
                 ...

An XML Base-aware schema validator tool should create this as the URL
for schemaLocation:

   http://www.example.org/BookCatalogue.xsd

The problem is that there is no "requirement" for schema validators to
support XML Base (and thusly no schema validators support it).  There is
no statement in the XML Schema spec saying "for a schema validator to be
conformant it must support XML Base". 

XLink, XInclude seem to be in the same predicament as XML Schemas, i.e.,
they state that XML Base can be used but there is no requirement.

This lack of clear direction will kill interoperability.

The problem seems to stem from the fact that they (XML Schemas, XLink,
XInclude) all "pass the buck" to XML Namespaces, which states:

"Several information items have a [base URI] or [declaration base URI]
property.  These items are computed according to [XML Base]"

Note that it does not say, "These items MUST BE computed according to
[XML Base]".  As a result, there is no requirement to support XML Base,
and everyone is left hanging.

XML Base is a great idea, but it sure doesn't seem very useful unless
there is a hard requirement for tools to support it.  Can someone please
clarify this issue for me?  Am I missing something?  /Roger

Received on Thursday, 21 March 2002 12:27:54 UTC