class Context_def;
class Context_specced_music;
class Dispatcher;
+class Dot_column;
+class Dot_configuration;
+class Dot_formatting_problem;
class Engraver;
class Engraver;
class Engraver_group;
class Simple_spacer_wrapper;
class Simultaneous_music;
class Simultaneous_music_iterator;
+class Skyline;
class Skyline_entry;
class Slur_configuration;
class Slur_score_state;