It's not auto-generated, but it's not difficult. There's three approaches likely to be reasonable. First, you could make a queryparser-impala package starting

It's not auto-generated, but it's not difficult. There's three approaches likely to be reasonable. First, you could make a queryparser-impala package starting with a copy of queryparser-hive, make the changes reflecting the differences you're aware of. Second, you could start from a description of the grammar and build it fresh, using queryparser-hive only as additional reference. Third, if Hive and Impala are close enough (I'm not sufficiently familiar with Impala to say) you could extend queryparser-hive to also work with Impala. In any case, a large corpus of Impala queries would be hugely valuable. IIRC, Heli took the first approach when going from Vertica to Hive; Matt took the second when adding Presto.