I've got some way through a (hopefully) useful completion for
PostgreSQL.  It's useful as it stands, but I have a few questions about
some bits of it.

1.  I use psql to get information from the database.  But what happens
if psql spits out an error?  At the moment, it just messes up the
display...

2.  How do you complete either a hostname or a path at the same point?
PostgreSQL accepts either a hostname or a directory containing a socket
after -h.

Anyway, I hope this is useful to somebody.

-Dom