implementing roman numeral harmonic analysis?

[Mark Polesky]

Hi everyone,

On a whim I decided to try to implement a roman numeral
harmonic analysis interface, entirely in scheme.  I hijacked
the Lyrics context for my analysis figures, and took
advantage of the brand new NullVoice context (which has been
in master for about a day now).

I got pretty far, but there are still some pretty basic
things that I don't know how to do.  The most important of
these are suspensions, where a line is drawn connecting the
suspension number to its resolution number, as in figured
bass (like V4-3).  Another need is to be able to have the
extender extend from one chord to another while an
intermediate chord gets a figure, like so:

   P6/4
I________I6

A third thing is showing the pivot chord, either by 
enclosing both interpretations in a box:

------
| I  |
| IV |
------

or doing something like this:

  I |
-----
| IV

Keep in mind, if you want to experiment with this, you'll
need the latest copy of engraver-init.ly in your installed
version:
http://git.savannah.gnu.org/gitweb/?p=lilypond.git;a=blob_plain;f=ly/engraver-init.ly;hb=df8a24

Anyway, I can't tell, but maybe this is a dead-end approach.
If so, what would be the better way to implement this?  Or
put another way, is there hope for this approach?

Thanks.
- Mark

harmonic-analysis.scm
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harmonic-analysis.ly
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harmonic-analysis.png
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