+#include "axis-group-interface.hh"
+#include "engraver.hh"
+#include "spanner.hh"
+
+class Vertical_align_engraver : public Engraver
+{
+ Spanner *valign_;
+ bool qualifies (Grob_info) const;
+ SCM id_to_group_hashtab_;
+
+public:
+ TRANSLATOR_DECLARATIONS (Vertical_align_engraver);
+
+protected:
+ virtual void derived_mark () const;
+ virtual void acknowledge_grob (Grob_info);
+ virtual void process_music ();
+ virtual void finalize ();
+ virtual void initialize ();
+};
+
+
+ADD_TRANSLATOR (Vertical_align_engraver,
+ "Catch groups (staffs, lyrics lines, etc.) and stack "
+ "them vertically.",
+ /* creats*/ "VerticalAlignment",
+ /* accepts */ "",
+ /* acks */ "axis-group-interface",
+ /* reads */ "",
+ /* write */ "");
+