lilypond mandolin tablature?

[Karl Berry]

The `Non-guitar tablatures' node in the lilypond 1.6.0 manual says:

       First you can change the number of strings, by setting the number of
    lines in the *note (lilypond-internals)TabStaff:: .  You can change the
    strings tuning. A string tuning is given as a Scheme list with one
    integer number for each string, the number being the pitch of an open
    string.

I'm very glad to know this :), but, forgive my ignorance, I don't know
how to translate this into what to type.  A concrete example would be
helpful.  In particular, what I want to produce is tablature for
mandolin, which has four (logical) strings, tuned e a d g (same as
violin).

I looked at the TabStaff node but didn't see anything to copy
there either.  From the input/test/tab-staff.ly file, I can guess that's
going to be something like
  StaffSymbol \override #'line-count = #4
but that by itself just got a syntax error (unexpected override).

Any pointers would be greatly appreciated.

Thanks,
address@hidden