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Re: Re[2]: Summary: Section 2: What does a URI identify?

From: Jonathan Borden <jonathan@openhealth.org>
Date: Tue, 19 Mar 2002 15:12:55 -0500
Message-ID: <02e701c1cf82$779731a0$0a2e249b@nemc.org>
To: "Williams, Stuart" <skw@hplb.hpl.hp.com>
Cc: "Paul Grosso" <pgrosso@arbortext.com>, <www-tag@w3.org>, "Chris Lilley" <chris@w3.org>, "McBride, Brian" <bwm@hplb.hpl.hp.com>
Stuart,

>
> I don't think the XML Base recommendation is the issue here. XML Base
gives
> a means to specify/determine the base URI to be used when resolving a
> relative URI. It is RFC2396 (which pre-dates the RDF recommendation) that
> makes '#foo' a "same document reference" and establishes that a base URI
is
> not applied when resolving a "same document reference".

I understand the interpretation. Reading section 4.2 carefully, "...
traversal of such a reference should not result in an additional retrieval
action. However ...

After "However" it goes on to talk about empty URI references, but before,
bare fragment identifiers. Given the context switches, "in other words" and
"howevers" it really is not clear to me that this cannot be interpreted as
allowing an application to construct an absolute URI reference from a bare
fragment identifier by prepending the base URI.

That is to say: while I do see the interpretation of "same document
references" as bare fragment identifiers, I similarly see the "wiggle room"
that allows an application such as RDF to 'normalize' bare fragments into
absolute URI references.

On the other hand this really really is like reading tea leaves, hence the
need for clarification. In the process of clarification, I am stating what I
perceive to be the needs of a class of applications.

[...]
>
> However, in delving into RFC 2396, found pretty clear that '#foo' is not a
> relative URI reference, and hence is not resolved with respect to an XML
> base.

It is completely clear, that "#foo" is not a relative URI, rather a fragment
identifier. "#foo" is pretty clearly a URI-reference according to the BNF.
All that one can conclude is that the rules of relative URI references do
not apply. The rules for same document references seem to be given in 4.2?

None of this is entirely clear to me.

> Section 4.1 of RFC 2396 is also pretty clear:
>
>    The semantics of a fragment identifier is a property of the data
>    resulting from a retrieval action, regardless of the type of URI used
>    in the reference.  Therefore, the format and interpretation of
>    fragment identifiers is dependent on the media type [RFC2046] of the
>    retrieval result.

Yup. What, then, is the position of the TAG regarding the "semantics" of an
XML Namespace URI _reference_ that contains a fragment identifier? What
about the semantics of a _bare fragment identifier_ which, err, still is a
legal XML Namespace depite the deprecation of relative URI references...

Again, practice as defined by widely adopted W3C Recommendations, seems to
run counter to RFC 2396 in some cases. Should fragment identifiers be
deprecated in XML Namespaces altogether?

Curiouser and curioser. This all is not at all clear to me, and seems to
have great implications.

Jonathan
Received on Tuesday, 19 March 2002 15:17:07 GMT

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