Re: Combine Text/Lyrics with bass figures

[Lukas-Fabian Moser]

Hi Urs, hi Moritz,

> > thanks for the improvements to my code! (I tend to stop thinking 
> > about it as soon as it works for my case, which always leaves lots of 
> > room for improvement.)
> Seems to be the opposite of my approach. I'm always starting to think 
> in terms of reusability and "packages" right away - leading to working 
> code much later than would be good ;-)
When your default working mode is "I need this worksheet tomorrow by 9 
o'clock", the approach of using the first sort-of viable solution 
becomes much more tempting ;-).

> > (2) There might also be cases where you have more that one row of arabic
> > numbers to indicate other options. My first intention here would be to have a
> > single layer for every key, that is used in the analysis. If there’s an option
> > to hide the layer where it is not used.
> Each layer is a Lyrics or FiguredBass context, [...]

That's exactly what occurred to me over lunch: Everything we talked 
about concerning spacing just expresses the fact that scale degrees and 
bass figures should behave as if they were independent contexts (one 
FiguredBass, one Lyrics).

So let's scrap the idea of inserting scale degrees artificially into 
bass figures where they do not belong!

Hence:

\version "2.20.0"

#(define (scale-degree degree)
      (if (eqv? degree 0)
          (markup #:null)
          (markup #:circle #:small #:number (number->string degree))))

#(define (bass-degree? obj)
   "A bass degree is either a number between 1 and 7 or 0 (eqv. to
nothing)!"
   (and (integer? obj) (> 8 obj) (< -1 obj)))

#(define (event-chord? obj)
   (and (ly:music? obj) (music-is-of-type? obj 'event-chord)))


#(define (figure-signature? obj)
   "A figure signature is either an EventChord music or a duration."
   (or
    (event-chord? obj)
    (ly:duration? obj)))

duration-from-event-chord =
#(define-scheme-function (chord) (event-chord?)
   (let ((els (ly:music-property chord 'elements)))
     (ly:music-property (first els) 'duration)))

scaledeg =
#(define-music-function (num signature) ((bass-degree? 0) figure-signature?)
   (let ((dur (if (ly:duration? signature)
                   signature
                   (duration-from-event-chord signature))))
     #{
       <<
       #(if (ly:music? signature)
            signature
            #{ s $signature #})
       \context Lyrics = "scaleDegrees" \lyricmode
       {
         \markup { #(scale-degree num) } $dur
       }
       >>
     #}))



<<
  \new Staff {
    \time 3/4
    \clef bass
    c4 d e f2 g4 as2^"or g sharp?" a4 b4 c'4 % Morgenlich leuchtend ...
  }
  \figures \with { \override 
VerticalAxisGroup.nonstaff-nonstaff-spacing.padding = 1 } {
    \scaledeg 1 4
    \scaledeg 2 <4 3>4
    \scaledeg 3 <6>4
    \scaledeg 4 <7>4
    \scaledeg 0 <6>
    \scaledeg 5 4
    \scaledeg 6 <6>2
    \scaledeg 6 <6>4
    \scaledeg 7 <6 5>4
    \scaledeg 1 4
  }
  \new Lyrics = "scaleDegrees" { \skip 1*8 }
>>


Of course this is just proof-of-concept: The Lyrics context should be 
created (and kept alive) automatically ... or, even better: it should be 
user-settable with an interface like:

\figures {

  \inject-scaledegrees-into-context "scaleDegrees"

  ...

}

which would enable all sorts of vertical configuration.

Best
Lukas