Standard/Stradella Bass support for accordion?

[David Kastrup]

Hi,

how hard would it be to support accordion notation properly?  Common are
European and American notation.

The Stradella bass system offers bass notes and chords (in most
registers, the bass notes will have additional choirs and be stronger
than the chord constituents).  Bass notes can be played on one of two
rows (that are a major third apart).  Chords are usually major, minor,
major with seventh and diminuished (the diminuished chords are usually
missing the fifth).

In the European notation, bass tones are written in the great octave in
the bass clef, and the chords are written out in the small octave (using
inversion IIRC to keep them within the bass clef).  Bass notes get their
name in uppercase subscripted, chords their name in lower case.

The American notation does not write out the chords but just gives their
base (in the small octave again).  When the chord is not "natural", it
gets superscripted with its kind (M for major, m for minor, dm for
diminuished, 7 for seventh).  The superscript, like an accidental, is
not repeated.

I won't talk about the French notation...

I won't vouch for all of the details, but that is the gist.  Note that
one can produce something like that with lilypond visually, but

a) one has to code the chords manually which means that it is not
trivial to produce output for, say, accordeon and piano and figured bass
from the same input.

b) chords and bass notes don't stay in their designated space when
transposed.

c) when chords are not written out, the midi output will not correspond
with the actual sound.

Any thoughts how much work would be involved in tackling any of those
three problems?  I would be willing considering to sponsor some
development here but one should flesh out what is sensible here in
advance, and how much work would need to get put in what area.

Thanks,

-- 
David Kastrup