OK, I give up.

Can someone (Kou?) please sketch out how to intercept
a Subversion transaction with a pre-commit hook and
throw each file matching, say, /\.rb$/ to some StyleChecker?

Based on Kou's svnlook,

  https://svn.collab.net/repos/svn/trunk/tools/examples/svnlook.rb

and the bindings,

  http://svn.collab.net/repos/svn/trunk/subversion/bindings/swig/ruby/svn/

it seems that Svn:Fs might be the answer, but I'm having
trouble figuring out SVN transactions -- the manual says
very little about these creatures.

Thanks,
--
Bil
http://fun3d.larc.nasa.gov