Re: NoteColumn without parents?

[Jean Abou Samra]

Le 19/10/2021 à 17:47, Thomas Morley a écrit :
> Hi,
>
> please consider:
>
> {
>    b4\glissando
>    \once \override NoteColumn.glissando-skip =
>      #(lambda (grob)
>        (pretty-print
>          (list
>            (cons 'X-parent (ly:grob-parent grob X))
>            (cons 'Y-parent (ly:grob-parent grob Y))))
>         #t)
>    c'
>    d'
> }
>
> I.e. NoteColumn seems to have no parents, at least I can't read any
> parent from 'glissando-skip.
> Is this on purpose?


If you use ly:message to avoid intermingling of
stdout with stderr, you will see that glissando-skip
is being read in the translation stage. What triggers
it is an acknowledger in the Glissando_engraver, in
Voice context. The default parent of PaperColumn for
NoteColumn is set by the Paper_column_engraver in
stop-translation-timestep; if there are several
voices, the Collision_engraver -- in Staff context,
so its acknowledgers run after the Glissando_engraver's --
will gather the NoteColumn grobs in a NoteCollision.
Consequently, glissando-skip is in all cases read
at a point of time by which the NoteColumn has no parent.

What is your objective?

Best,
Jean