The "XML library" that comes with Ruby is REXML, which uses only regular expressions to 'parse' XML into the tree structure that it exposes via its API.
Sure is! Actually, I can't even remember if it has the functionality nailer's talking about. As far as I know all rubyists permanently abandon REXML approximately 20 minutes into their first coding session involving anything to do with XML.
Gets to the point where other libraries are so common that they may as well be in core, though. I wonder if there's any rubygems installation anywhere that doesn't have hpricot.
It is a stinking pile of shit.