Re: Extra Vietnamese unaccent rules

Hi,


I am interested in this thread.

> On May 27, 29 Heisei, at 10:41, Michael Paquier <michael.paquier@gmail.com> wrote:
> 
> On Fri, May 26, 2017 at 5:48 PM, Thomas Munro
> <thomas.munro@enterprisedb.com> wrote:
>> Unicode has two ways to represent characters with accents: either with
>> composed codepoints like "é" or decomposed codepoints where you say
>> "e" and then "´".  The field "00E2 0301" is the decomposed form of
>> that character above.  Our job here is to identify the basic letter
>> that each composed character contains, by analysing the decomposed
>> field that you see in that line.  I failed to realise that characters
>> with TWO accents are described as a composed character with ONE accent
>> plus another accent.
> 
> Doesn't that depend on the NF operation you are working on? With a
> canonical decomposition it seems to me that a character with two
> accents can as well be decomposed with one character and two composing
> character accents (NFKC does a canonical decomposition in one of its
> steps).
> 
>> You don't have to worry about decoding that line, it's all done in
>> that Python script.  The problem is just in the function
>> is_letter_with_marks().  Instead of just checking if combining_ids[0]
>> is a plain letter, it looks like it should also check if
>> combining_ids[0] itself is a letter with marks.  Also get_plain_letter
>> would need to be able to recurse to extract the "a".
> 

Thanks for reporting and lecture about unicode.
I attached a patch as the instruction from Thomas. Could you confirm it.

> Actually, with the recent work that has been done with
> unicode_norm_table.h which has been to transpose UnicodeData.txt into
> user-friendly tables, shouldn't the python script of unaccent/ be
> replaced by something that works on this table? This does a canonical
> decomposition but just keeps the first characters with a class
> ordering of 0. So we have basic APIs able to look at UnicodeData.txt
> and let caller do decision making with the result returned.
> -- 
> Michael


Thanks, i will learning about it.

---
Dang Minh Huong