New line-breaking rules prohibits incremental processing

[adah1972]

@filodej

Hi Petr,

Newer UAX-14 versions have rules like the following:

PO × OP NU
PO × OP IS NU
(AK | [◌] | AS) × (AK | [◌] | AS) VF

I.e. looking ahead (for more than one character) is needed. This makes incremental processing impossible, I think.

I think I will have to retire the lb_process_next_char API before supporting such rules.

Any other ideas?

[adah1972]

Commit 322f229 has introduced LB25 tailoring, as my first try to implement the lookahead logic. Tailoring is only enabled when using the set_linebreaks API, but not when using just lb_process_next_char.