> BTW, this code sorely needs tests, so when you find a bug (either in
> the original code or in changes you introduced temporarily), if you
> could add corresponding tests, that would be a great help.

Hi Stefan, hi João,

Thanks a lot.  I managed to iron out the bugs in a way that I’m happy
with.  It seems to work well with everything I tested so far, and I went
ahead and added some tests.

Please have a look.