/**
* \post:
* - \c result = a new \c bitset of size \c ::nritems such that any bit \c i
* is set iff <tt>ritem[i]</tt> is a nonterminal after which all ritems in
* the same RHS are nullable nonterminals. In other words, the follows of
* a goto on <tt>ritem[i]</tt> include the lookahead set of the item.
*/
static bitset
ielr_compute_ritem_sees_lookahead_set (void)
{
bitset result = bitset_create (nritems, BITSET_FIXED);
unsigned int i = nritems-1;
while (i>0)
{
--i;
while (!item_number_is_rule_number (ritem[i])
&& ISVAR (ritem[i])
&& nullable [item_number_as_symbol_number (ritem[i]) - ntokens])
bitset_set (result, i--);
if (!item_number_is_rule_number (ritem[i]) && ISVAR (ritem[i]))
bitset_set (result, i--);
while (!item_number_is_rule_number (ritem[i]) && i>0)
--i;
}
if (trace_flag & trace_ielr)
{
fprintf (stderr, "ritem_sees_lookahead_set:\n");
debug_bitset (result);
fprintf (stderr, "\n");
}
return result;
}
void
debug_bitsetv (bitsetv bsetv)
{
bitset_windex i;
for (i = 0; bsetv[i]; i++)
{
fprintf (stderr, "%lu: ", (unsigned long int) i);
debug_bitset (bsetv[i]);
}
fprintf (stderr, "\n");
}
