Accessing a grob from within a music function

[Urs Liska]

Hi,

I'm trying to write a function to push a note column like this:

pushLeftBroken =
#(define-music-function ()()
   #{
     \once \override NoteColumn.X-offset = 3
   #})

But I need to make that "3" depend on some characteristics of the actual
note column. Basically I need the width of the note column, including
attached accidentals.

I know how to get to the accidental(s) within a note column, but if I'm
not mistaken there's no actual grob inside that.

Probably music-function isn't the right approach?

What I need is a way to say something like

\once \override NoteColumn.X-offset = #(+ 3
extent-of-all-accidentals-in-the-note-column)

Any ideas?
TIA
Urs

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