[webkit-dev] XML Processor Profiles & WebKit

Alex Milowski alex at milowski.org
Tue Jun 15 01:53:21 PDT 2010

The XML Processing Model Working Group at the W3C has
been recently working on XML processor profiles as part of
our subsequent work after the XProc recommendation.  There
is currently a draft at:


I distinctly want one of the XML processor profiles to be that
which a web browser does when processing XML content.

I've been doing some research as to how WebKit uses libXML to
process XML and here's what I've reported back to the XProc
working group so far:

* does not read the external subset.
* does read the internal subset and provide any attribute
  normalization as specified per the XML recommendation
  for non-validating parsers.
* does default attributes read in the internal subset.
* does process and xml:base attributes properly
* does not process ID/IDREF to allow DOM's getElementById() to work.
* does not process xml:id attributes to allow DOM's getElementById() to work.
* reports all whitespace as text nodes in the DOM regardless of what is
  in the internal subset.

While I'd like xml:id and/or ID/IDREF to work along with the DOM's
getElementById(), I'm not sure about the historical or technical contexts
as to why they currently do not.

Basically, the profile would be much like what is described as the
"minimum XML processor profile" except that reading the external
subset would not be required.

Thoughts?  We could certain ask for more.

I'm curious about xml:id handling.  I know there is also a bit of XLink
supported for SVG use but it is also incomplete.

If you all had to define an XML Processor Profile for WebKit, what
would you want it to do?

--Alex Milowski
"The excellence of grammar as a guide is proportional to the paucity of the
inflexions, i.e. to the degree of analysis effected by the language

Bertrand Russell in a footnote of Principles of Mathematics

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