I have written a C-based XML parser as a ruby plugin.  I managed to
benchmark it against REXML and Hpricot, and it appears to run quite
speedily (http://involution.com/images/xmlshootout.png).

The source code is here:
http://involution.com/xaggly.tar.gz

Unfortunately, my XPath support is very primitive right now.  The
package only supports fully qualified queries, and attribute searches
aren't working yet.  So, you can search /html/body/* to give you all
of the tags open under body, but things like //p and //p[class=foo] do
not work yet.  Attributes are parsed and can be accessed from Ruby
though.

I was trying to jigger this plugin to a gem, but it appears that mkmf
doesn't detect the presence of Flex and Bison files automatically.  Is
there a supported or standard for doing such a thing?

Regards,

Tony Perrie
http://involution.com