DECLARE_SCHEME_CALLBACK (calc_length, (SCM));
DECLARE_SCHEME_CALLBACK (calc_stem_end_position, (SCM));
DECLARE_SCHEME_CALLBACK (calc_stem_info, (SCM));
DECLARE_SCHEME_CALLBACK (calc_positioning_done, (SCM));
DECLARE_SCHEME_CALLBACK (calc_length, (SCM));
DECLARE_SCHEME_CALLBACK (calc_stem_end_position, (SCM));
DECLARE_SCHEME_CALLBACK (calc_stem_info, (SCM));
DECLARE_SCHEME_CALLBACK (calc_positioning_done, (SCM));