DECLARE_SCHEME_CALLBACK (print, (SCM));
DECLARE_SCHEME_CALLBACK (calc_control_points, (SCM));
DECLARE_SCHEME_CALLBACK (calc_direction, (SCM));
DECLARE_SCHEME_CALLBACK (pure_height, (SCM, SCM, SCM));
DECLARE_SCHEME_CALLBACK (height, (SCM));
DECLARE_SCHEME_CALLBACK (print, (SCM));
DECLARE_SCHEME_CALLBACK (calc_control_points, (SCM));
DECLARE_SCHEME_CALLBACK (calc_direction, (SCM));
DECLARE_SCHEME_CALLBACK (pure_height, (SCM, SCM, SCM));
DECLARE_SCHEME_CALLBACK (height, (SCM));