SCM context_property, SCM grob_property_path, SCM val);
SCM updated_grob_properties (Context *tg, SCM sym);
Context *find_context_below (Context *where,
SCM context_property, SCM grob_property_path, SCM val);
SCM updated_grob_properties (Context *tg, SCM sym);
Context *find_context_below (Context *where,