Re: Creating chord names like C7/F#7

[Tim McNamara]

On Jun 9, 2010, at 3:07 AM, snozpacker wrote:

> For a certain polytonal piece, I need to display chord names of the  
> form
> "C7/F#7".  That is, I need to be able to have an entire chord after  
> the
> slash, not just the root.
>
> I already know how to modify the main part of the chord using
> chExceptionMusic, like in the example code below.  But I can't  
> figure out
> how to use this to modify the part after the slash.
>
> If I only had to do this once, I suppose I could just take one type  
> of chord
> that I didn't need, hard code it as C7/F#7 in chExceptionMusic, and  
> call it
> in \chords whenever I needed it.  But I have to do it for many  
> different
> chords.
>
> What is the correct way to do this?

I don't know that there is a way to enter polychords into Lilypond,  
but by some conventions at least you don't want to display them as a  
slash chord (e.g., triad/triad) but above each other separated by a  
horizontal line.

C           C7
-   or      -
A           F#7

Polychords are usually triads over triads rather than tetrads over  
tetrads, although your needs might be different.  It might be easier  
to write the exception using triads using a horizontal line rather  
than a slash to specify them as polychords.

Hopefully someone else will know how to code these; you may have to  
write a Scheme function to do this (and if you succeed, submit it to  
be included!).  There was discussion on this about a year ago with no  
resolution, IIRC.