[plt-scheme] running an MzScheme debugger in Emacs?

Eli Barzilay writes:
 > I didn't port it to v4 yet -- but the part that you want is already in
 > v4.  See this:
 > 
 >   http://docs.plt-scheme.org/reference/enter.html

This is awesome, thanks!  Now I can stop using (provide (all-defined))
just to test internal functions.  (I may still use it for other
reasons-- I haven't settled on the best practice for doing module
exports.)  And it re-loads modules when their source files change!
I've been wanting this forever!!

--dougorleans at gmail.com