I wrote:
> Nguyen Le Hoang Kha <nlhkha(at)gmail(dot)com> writes:
>> Most of the time in Vietnamese language, there are up to 2 accents in a
>> character. These unaccent rules are added to handle such cases (which are
>> very common).
> I can't see any reason not to add these --- any objections out there?
Oh, wait a minute. Patching unaccent.rules directly isn't the way
to do this; that file is supposed to be generated by
generate_unaccent_rules.py. Can you see how to modify that script
to produce these rules?
regards, tom lane