Re: Chords and what they mean

[David Kastrup]

Johan Vromans <address@hidden> writes:

> On Mon, 21 Sep 2015 11:00:13 +0200
> David Kastrup <address@hidden> wrote:
>
>> Johan Vromans <address@hidden> writes:
>> > It is easy to instruct LilyPond that a chord of form <c ees g> must be
>> > shown as minor (e.g., Cm), but can I do the other way around? E.g.,
>> > define a 'foo' so that X:foo means <c eis g> or whatever notes I want?
>> 
>> Possible but obscure.  Take a look at the \powerChords command which
>> does exactly that (but should be the default in my opinion as the
>> behavior without it is not useful).
>
> Maybe I do not get the full meaning of \powerChords, but all it seems to do
> is print the chord name for a:1.5 as A5. What I was looking for is a way to
> define that, for example, 
>
>   a:five  -> <a e> -> A5
>
> So it is the *input* side I'd want to change.

Ah, ok.

It would be something like

#(set!
  default-chord-modifier-list
  (acons 'five (lambda (pitches)
                 (remove-step (pitch-step (ly:make-pitch 0 2 0)) pitches))
         default-chord-modifier-list))

to do that.  Again in the "possible but obscure" ballpark.  And you
probably need to pull in the definitions of remove-step and pitch-step
from scm/chord-ignatzek-names as well.

-- 
David Kastrup