+/* The rule currently being defined, and the previous rule. Point to
+ the first symbol of each list: their lhs. */
+symbol_list *current_rule = NULL;
+symbol_list *previous_rule = NULL;
+
+
+/* Create a new rule for LHS in to the GRAMMAR. */
+
+static void
+grammar_rule_begin (symbol_t *lhs)
+{
+ if (!start_flag)
+ {
+ startsymbol = lhs;
+ start_flag = 1;
+ }
+
+ /* Start a new rule and record its lhs. */
+ ++nrules;
+ ++nritems;
+
+ previous_rule = grammar_end;
+ grammar_symbol_append (lhs);
+ current_rule = grammar_end;
+
+ /* Mark the rule's lhs as a nonterminal if not already so. */
+
+ if (lhs->class == unknown_sym)
+ {
+ lhs->class = nterm_sym;
+ lhs->number = nvars;
+ ++nvars;
+ }
+ else if (lhs->class == token_sym)
+ complain (_("rule given for %s, which is a token"), lhs->tag);
+}
+