How to modify chordmode parser?

[David Kastrup]

Hi,

accordion entry again...  I want to distinguish single bass buttons from
chord buttons.

Single basses are usually located in a lower octave.  When written out,
you usually arrive at something like

c,:1 c:m g,:1 c:m

Now that is cumbersome to write, so I would like to be able to write

C c:m G c:m

instead which corresponds better with accordion notation.  This appears
to involve two components:
a) additional capital notenames that are one octave lower
b) and that don't trigger chord buildup. C:m would be an error,
   actually.

It would also be nice to write

c:m/C

which would not create an actual inversion, but just tack the (lower
octave) bass tone to the bottom without rearranging the chord.

How much work for the chordmode parser to achieve this?  Can this be
done from Scheme, or is C++ hackery needed?

-- 
David Kastrup