[HarfBuzz] Itemising Japanese scripts

[Khaled Hosny]

I’m wondering what is the best practice of itemising Japanese scripts
(Han, Hiragana, Katakana), should they be merged somehow or is it better
to keep them in separate runs?

I’m currently treating them as separate scripts so they end up in
operate runs, but in the ~7000 characters of Japanese text I’m testing
with I get ~2000 runs, if it were some English or Arabic text it would
be just 1 run so it seems quite inefficient (though I didn’t make any
measurements).

Regards,
Khaled