+#include "note-collision.hh"
+
+#include "engraver.hh"
+#include "axis-group-interface.hh"
+
+class Collision_engraver : public Engraver
+{
+ Item *col_;
+ Link_array<Grob> note_columns_;
+
+protected:
+ virtual void acknowledge_grob (Grob_info);
+ virtual void process_acknowledged_grobs ();
+ virtual void stop_translation_timestep ();
+public:
+ TRANSLATOR_DECLARATIONS (Collision_engraver);
+};