* src/gram.h (rule_number_t, RULE_NUMBER_MAX, int_of_rule_number)

* src/gram.h (rule_number_t, RULE_NUMBER_MAX, int_of_rule_number)
(item_number_of_rule_number, rule_number_of_item_number): New.
* src/LR0.c, src/closure.c, src/derives.c, src/derives.h,
* src/gram.c, src/lalr.c, src/nullable.c, src/output.c, src/print.c,
* src/print_graph.c, src/reader.c, src/reduce.c, src/reduce.h:
Propagate their use.
Much remains to be done, in particular wrt `shorts' from types.h.