+void
+Separating_group_spanner::add_spacing_unit (Grob *me, Item *i)
+{
+ Pointer_group_interface::add_grob (me, ly_symbol2scm ("elements"), i);
+}
+
+ADD_INTERFACE (Separating_group_spanner, "separation-spanner-interface",
+ "A spanner that calculates spacing constraints (\"rods\") "
+ "using the @code{separation-item-interface} grobs in @code{elements}.",
+
+ /* properties */
+ "elements "
+ "padding");