Re: Custom note names, or meta-score?

[Aaron Hill]

On 2021-07-31 10:43 am, Craig Comstock wrote:
> So said another way, I’d like to write a meta-score like { aa4 aa2 aa
> aa ab ab ab ac ac ca ca } and those note names relate to a set of
> pitches determined maybe in another file (not code hopefully) so that
> as the pitches are chosen/changed it is easy to regenerate the
> score/parts.

The following (minimally-tested) proof-of-concept should get you pretty 
close to your goal:

%%%%
\version "2.22.0"

#(define generic-notes '())

defineGenericNote =
#(begin
  (define (note-event? arg)
   (and (ly:music? arg)
        (music-is-of-type? arg 'note-event)))
  (define-void-function (name music) (symbol? note-event?)
   (if (ly:assoc-get name generic-notes #f)
    (ly:input-warning (*location*)
     "note name ~s is already defined" name)
    (set! generic-notes (cons (cons name music) generic-notes)))))

registerGenericLanguage =
#(define-void-function () ()
  (define pitch-names
   (let ((len (length generic-notes)))
    (cons 'generic
     (map (lambda (n idx)
           ;; Encode index within alteration.
           (cons (car n) (ly:make-pitch 0 0 (/ idx len))))
      generic-notes (iota len)))))
  (set! language-pitch-names (cons pitch-names language-pitch-names)))

fixupGenericMusic =
#(define-music-function (music) (ly:music?)
  (define (fixup! m)
   (let* ((pitch (ly:music-property m 'pitch))
          (oct (ly:pitch-octave pitch))
          (alt (ly:pitch-alteration pitch))
          (idx (numerator alt))
          (note (cdr (list-ref generic-notes idx))))
    ;; Adjust pitch, applying octave transposition.
    (ly:music-set-property! m 'pitch
     (ly:pitch-transpose
      (ly:music-property note 'pitch)
      (ly:make-pitch oct 0 0)))
    ;; Merge articulations.
    (ly:music-set-property! m 'articulations
     (append (ly:music-property note 'articulations '())
             (ly:music-property m 'articulations '())))
    ;; Merge tweaks.
    (ly:music-set-property! m 'tweaks
     (append (ly:music-property note 'tweaks '())
             (ly:music-property m 'tweaks '())))))
  (map fixup! (extract-typed-music music 'note-event))
  music)

toplevel-music-functions =
#(cons fixupGenericMusic toplevel-music-functions)

% NOTE: Pitches here use the current \language setting.
\defineGenericNote qw d'
\defineGenericNote er d'-.
\defineGenericNote ty \tweak font-size -3 fis'

\registerGenericLanguage
\language "generic"

{ qw4 er2 ty8-> <qw' \tweak color red ty> }
%%%%

Each generic note name is mapped to a note event that specifies the 
desired pitch along with tweaks and articulations.  Target pitches need 
not be unique.

As an implementation detail, a generic note is associated with a 
placeholder pitch with a special alteration value for looking up the 
reference note event.  A top-level handler is installed that processes 
music to convert these temporary pitches into the correct ones while 
merging tweaks and articulations.  As shown above with qw', the 
reference pitch can be shifted by octave as needed.

Chords mostly work, however certain articulations need to be applied to 
the chord-event rather than individual notes.  Additional logic is 
needed to support chords fully, and it might be useful for generic note 
names to be chords as well.

Key signatures do not support the generic note names as they are 
processed before the top-level handler.  For now, you would have to 
manually specify the pitch:

%%%%
\key #(ly:make-pitch 0 1 0) \major   %{ equiv. to \key d \major %}
%%%%

-- Aaron Hill

note-name-articulations.cropped.png
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