\version "2.19.80"
\language "english"
\include "oll-core/package.ily"
\loadPackage edition-engraver
\consistToContexts #edition-engraver Voice.Staff.Score

#(define (pitch-or-chord? obj)
   (or (ly:pitch? obj)
       (if (ly:music? obj)
           (equal? (ly:music-property obj 'name) 'EventChord))))

#(define (pitch->pitch-list pitch)
   (list pitch))

#(define (chord->pitch-list chord)
   (map (lambda (element)
          (ly:music-property element 'pitch))
        (ly:music-property chord 'elements)))

condGrobTweak = 
#(define-music-function (use_octave target grob_proc)((boolean? #f) pitch-or-chord? procedure?)
   (let ((pitches (if (ly:pitch? target)
                      (pitch->pitch-list target)
                      (chord->pitch-list target))))
     #{
       \override NoteHead.before-line-breaking =
       #(lambda (grob)
          (let* ((cause (ly:grob-property grob 'cause))
                 (pitch (ly:prob-property cause 'pitch))
                 (note (ly:pitch-notename pitch))
                 (alteration (ly:pitch-alteration pitch))
                 (octave (ly:pitch-octave pitch)))
            (map (lambda (this-pitch)
                   (if (and (eqv? alteration (ly:pitch-alteration this-pitch))
                            (eqv? note (ly:pitch-notename this-pitch))
                            (or (not use_octave)(eqv? octave (ly:pitch-octave this-pitch))))
                       (grob_proc grob)))
                 pitches)))   
     #}))

#(define (omit-accidental grob)
   (let ((accidental (ly:grob-object grob 'accidental-grob)))
     (if (ly:grob? accidental)
         (ly:grob-set-property! accidental 'stencil #f)
         )))

\addEdition accidentals
\editionMod accidentals 1 0/4 Voice \once \condGrobTweak <cs gs> #omit-accidental

{ <cs' es' gs' bs'> }