tab_dim_func tab_natural_dimensions;
int tab_natural_width (struct tab_table *t, struct outp_driver *d, int c);
int tab_natural_height (struct tab_table *t, struct outp_driver *d, int r);
tab_dim_func tab_natural_dimensions;
int tab_natural_width (struct tab_table *t, struct outp_driver *d, int c);
int tab_natural_height (struct tab_table *t, struct outp_driver *d, int r);