\version "2.19.81"
#(define Ez_numbers_engraver
(make-engraver
(acknowledgers
((note-head-interface engraver grob source-engraver)
(let* ((context (ly:translator-context engraver))
(tonic-pitch (ly:context-property context 'tonic))
(tonic-name (ly:pitch-notename tonic-pitch))
(grob-pitch
(ly:event-property (event-cause grob) 'pitch))
(grob-name (ly:pitch-notename grob-pitch))
(delta (modulo (- grob-name tonic-name) 7))
(note-names
(make-vector 7 (number->string (1+ delta)))))
(ly:grob-set-property! grob 'note-names note-names))))))
\layout {
ragged-right = ##t
\context {
\Voice
\consists \Ez_numbers_engraver
}
}
\new RhythmicStaff { a4 b8 a }
and this is the error I get
Interpreting music..document.ly:8:26 <0>: In procedure
ly:pitch-notename in
expression (ly:pitch-notename tonic-pitch):
..document.ly:8:26 <1>: Wrong type argument in position 1 (expecting
Pitch): ()
Any suggestion to fix it?