W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > December 2005

Implementation notes

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Mon, 05 Dec 2005 16:14:56 +0000
Message-ID: <43946780.9050806@hpl.hp.com>
To: "'public-rdf-in-xhtml task force'" <public-rdf-in-xhtml-tf@w3.org>

Very early version is at


This is based on my earlier work from about a year ago.



1) The rules are simpler, definitely an improvement.

2) The subject rules get overly complicated, because of all the special 
casing to do with meta and link.

3) Reification looks hard to do in this framework.

4) The original framework was fairly declarative. The implementation 
follows that. However, the subject and object rules in the specification 
are rather procedural - if A then X else if B then Y else if C then Z 
... etc. (For example, meta and link processing, or datatype processing 
...). Converting these into declarative rules I have a lot of

if A then X
if B and not A then Y
if C and not A and not B then Z

Some points on specification:


  A meta or link without its own about attribute and positioned directly 
within the head of a document will automatically apply to the document 
itself. Effectively, the head of an XHTML2 document contains an implicit 
what happens if the head has an explicit @about?

- in subject resolution, when an about from an ancestor is
resolved, the xml base value is from that ancestor, not the current node. Literal from string value of meta
is mistitled.

[[It does not help to escape the content, since the output would simply 
be a string of text containing numerous ampersands:]]

technically incorrect but in practice correct

<head about="">
     Author: <span property="dc:creator">Albert Einstein</span>
     <h2 property="dc:title">
       E = mc<sup>2</sup>: The Most Urgent Problem of Our Time
poor example? h2 in head?

I am not expecting to do more work on this for about ten days.

Received on Monday, 5 December 2005 16:16:59 UTC

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