"First edition" ≠ "first printing". The edition number is always explicit, because for a new edition the pages are re-set. For a new printing the pages are (t

"First edition" ≠ "first printing". The edition number is always explicit, because for a new edition the pages are re-set. For a new printing the pages are (traditionally) not re-set, which is why the printing number has to be encoded in some manually-updatable way.