31.7 Orthogonal treatment of exhaustion

The treatment of parse exhaustion is very awkward. marpa_r_start_input() returns success on exhaustion, while marpa_r_earleme_complete() either returns success or a hard failure, depending on circumstances. See marpa_r_earleme_complete(), and marpa_r_start_input().

Ideally the treatment should be simpler, more intuitive and more orthogonal. Better, perhaps, would be to always treat parse exhaustion as a soft failure.