I started to look over the documentation for our next product release, which is done using DocBook, as reported before. As usual when I start doing stuff like this, I drift into ToolTestMode (a state of something almost, but not entirely, unlike actual work, where one spends hours and hours optimizing the tool set for a task that would have been done ages ago if one had used a piece of paper and a pen to solve it), so I gave James Clark’s nXML mode a try.

This thing is just great.

Tim Bray had a comment on this some time ago:

There are 12,587 lines of elisp here apparently implementing a complete XML 1.0 processor and RelaxNG validation engine. Words fail me.