It appears that media types, fragment identifiers, and XPointer are
actually related.
In my understanding, URIs can have fragment identifiers such as "#foo".
How to interpret fragment identifiers depends on the media type. (Could
somebody provide pointers to relevant RFCs?)
On the other hand, the XML community is developing a mechanism called XPointer.
(http://www.w3.org/TR/WD-xptr)
"XPointers operate on the tree defined by the elements and other
markup constructs of an XML document.
An XPointer consists of a series of location terms, each of which
specifies a location, usually relative to the location specified by
the prior location term. Each location term has a keyword (such as id,
child, ancestor, and so on) and can have arguments such as an instance
number, element type, or attribute. For example, the location term
child(2,CHAP) refers to the second child element whose type is CHAP."
XPointer is intended to be used as a fragment identifier.
"The locator for a resource is typically provided by means of a
Uniform Resource Identifier, or URI. XPointers can be used as fragment
identifiers in conjunction with the URI structure to specify a more
precise
sub-resource."
I personally have expected that XPointer is usable for every XML document
no matter what the media type is. But I am apparently wrong. Do we need
a top-level media type "xml" or some convention such as "image/xml.vml"
so that XPointer can be used for any XML document? Or, are "text/xml" and
"application/xml" enough?
Cheers,
Makoto
Fuji Xerox Information Systems
Tel: +81-44-812-7230 Fax: +81-44-812-7231
E-mail: murata(_at_)apsdc(_dot_)ksp(_dot_)fujixerox(_dot_)co(_dot_)jp