Re: [idn] stringprep comment 5: hangul conjoining sequence

["Soobok Lee" <lsb@postel.co.kr>]

Hi, Kent

----- Original Message ----- 
From: "Kent Karlsson" <kentk@md.chalmers.se>
 
> >  3. Compatibility hangul jamos are mapped into conjoining 
> > jamos without any fillers.
> 
> Compatibility (non-conjoining) Hangul letters are best prohibited.  Doing
> the correct mapping is not expressible in via nameprep without adding
> a new, special for Hangul, mechanism.  Would there be any major problems
> just prohibiting them? (Allowing only the conjoining jamo and syllable characters.)
> 

That's impossible. Unicode-issued KSC5601 ==> UNicode mapping tables
 provides "hangul legacy code jamos --> Unicode u+3??? compability jamos".
 When ordinary Korean users enter hangul jamo sequence in 
all version of Windows or LInux which adop the table above, 
those legacy-coded jamo sequences will be eventually converted into 
Unicode compatibility jamos sequence. There is no way to input directly  conjoining jamo sequences
including necessary fillers and that will be painfully complex to end users.

And Even windows and linux does not render correctly the conjoining jamo sequence including fillers.
The compability jamos are the only viable alternative for correct jamo sequence rendering in
commerical windows and linux platforms.

Soobok