#define set_object(x, y) internal_set_object (ly_symbol2scm (x), y)
#define del_property(x) internal_del_property (ly_symbol2scm (x))
#define set_object(x, y) internal_set_object (ly_symbol2scm (x), y)
#define del_property(x) internal_del_property (ly_symbol2scm (x))