struct Complex_music;
struct Complex_staff;
struct Complex_walker;
+struct Crescendo ;
struct Cresc_req;
struct Directional_spanner;
struct Decresc_req;
struct Group_feature_req;
struct Idealspacing;
struct Identifier;
+struct Input;
+struct Input_register;
struct Input_file;
struct Input_music;
struct Input_score;