Re: Lilypond and Jazz chords

[David Kastrup]

Kieren MacMillan <address@hidden> writes:

> Hi David,
>
>> The engraver would convert <c d f bf> into something akin to c c' d' f'
>> bf' (somewhat opaque example since the first is the root pitch and the
>> others are the relation to the root note, expressed as intervals from
>> c').  There would be one or several markups for interpreting the c' d'
>> f' bf' part of the list.  And likely some exceptions mechanism.
>
> I personally think like an input like
>
>   <d f bf>/c  ==>  Bb/C or Bb(6/3)/C or etc.
>   <c d f bf>  ==>  C7(sus2,4) or etc.
>
> would be a huge help (at least to me). Wouldn’t have to be exactly
> like that, of course… but should be a clear and easy way to explicitly
> separate the chord(s), inversion(s), and root(s) into bits to be
> reassembled into a name later.

Well, the above was not supposed to represent input to LilyPond: it's
what the chord naming functions work with internally.

LilyPond's input is basically just the notes in arbitrary order.
However, there are additional properties on single notes: root (boolean
flag for the root note), inversion (boolean flag for the inversion
note), octavation (octave difference to bring the note into an octave
suitable for recognizing the uninverted chord).

Creating nice music functions for conveying the same information might
be a start, but I don't think that it would suffice for everything
called out as "context information" in this thread.

One thing to note is that stuff like the "octavation" property should be
sufficient for hauling guitar chord shapes back into the realm of the
chord namer by placing everything back into its functional octave (and
presumably removing duplicates, haven't tried).

-- 
David Kastrup