extern struct td *td_now;
extern struct td *td_first;
extern struct td *td_temp;

extern struct column *column_now;
extern struct column *column_first;
extern struct column *column_temp;

extern struct table *table_now;

extern struct property *property_now;
extern struct property *property_first;
extern struct property *property_temp;

extern struct class *class_now;
extern struct class *class_first;
extern struct class *class_temp;
extern struct class *class_stack;

extern int level;

extern char *supplier_bsu;

extern int element_number_now;
