Ah, a rare case of premature documentation. That is, documentation for a
feature that is due, but not released yet. I'll update the docs to hide
the mention of the detailed interface for the moment.
>
> What am I doing wrong?
Nothing.
> It seems like my cabal does not support anything other than exitcode...
That's right. No released version supports the detailed interface yet.
Just recently we think we've settled on the final interface and will
hopefully get that implemented in the darcs version soon. If you'd like
to be guinea pig for that then I expect Thomas would like to talk to
you.
Duncan