scheme engraver for StaffTab notation

[Ricardo Wurmus]

Hi,

a while ago I wrote a scheme engraver that outputs something close to
StaffTab notation.  StaffTab notation is a mix of standard two staff
notation with a few elements of tabulature tailored to the free hands
methods of playing the Chapman Stick.

Here's the essence of what it does:

    The engraver changes the noteheads dependent on fingering and string
    position information (e.g. c-3\4 would result in the note c rendered
    with a triangular notehead representing the third finger, plus a
    string marker on the line matching the fourth string).  In addition,
    the fret position dependent on the selected tuning is computed and
    printed above the staff (this looks still a bit uglier than what I
    can accept).

I actually first worked on this in 2011 and didn't feel comfortable
enough with the results to dare submitting a patch set.  The engraver
does not yet result in the very same output one would expect from
hand-crafted StaffTab notation, but it gets reasonably close, at least
for my purposes.

As the intersection of people playing the Chapman Stick and using
Lilypond for their notation needs is probably very small I wonder if it
makes sense to polish this engraver a little and submit it for inclusion
in Lilypond.  The alternative is probably watching it the engraver go
stale and bitrot.

Is an engraver for StaffTab notation (plus some standard Chapman Stick
tuning definitions) something you'd think would be an appropriate
contribution to Lilypond or is it too much of a niche application and
should rather remain as an external engraver?

-- Ricardo