ADD_ACKNOWLEDGER (Rhythmic_column_engraver, stem);
ADD_ACKNOWLEDGER (Rhythmic_column_engraver, rhythmic_head);
ADD_ACKNOWLEDGER (Rhythmic_column_engraver, arpeggio);
ADD_TRANSLATOR (Rhythmic_column_engraver,
ADD_ACKNOWLEDGER (Rhythmic_column_engraver, stem);
ADD_ACKNOWLEDGER (Rhythmic_column_engraver, rhythmic_head);
ADD_ACKNOWLEDGER (Rhythmic_column_engraver, arpeggio);
ADD_TRANSLATOR (Rhythmic_column_engraver,