Re: Combining characters (was: Re: [idn] hostname historyhell)

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

Now that <I><dot-above> is downcased to <i> as an exceptional case,
Then,  we have an interesting question:
which direction should we  lowercase   <I><dot-above><acute>   into ?

  1.    <I dot-above><acute>     ===>     <i><acute>    :  CaseMap(NFKC(x))
  2.    <i><dot-above><acute>                                       :  NFKC(CaseMap(x))

Does the whole combining sequence inherit the bicameral property of
the base character  or the partial combining sequence  minus the last mark ?
 
Soobok Lee
  
----- Original Message ----- 
From: "David Hopwood" <david.hopwood@zetnet.co.uk>
To: "Soobok Lee" <lsb@postel.co.kr>; <idn@ops.ietf.org>
Sent: Monday, November 26, 2001 3:46 AM
Subject: Re: Combining characters (was: Re: [idn] hostname historyhell)


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> 
> Soobok Lee wrote:
> > Does a combining sequence inherit the bicameral  characteristic of the
> > leading letter ?
> 
> It doesn't matter: folding the base character of the combining sequence
> is sufficient (usually; <I><dot-above> and sequences that include
> Greek ypogegrammeni are exceptions).
> 
> > For example,  
> >
> > <A acute> can be lowercased into <a acute> ?
> > Then, <A><acute> ==> <a><acute> ? <A><acute><diaeresis>... ==>
> > <a><acute><diaeresis>... ?
> 
> Yes.
> 
> > Can <I><dot-above> be lowercased into <i><dot-above> or not?
> 
> The case-folded form [*] of <I><dot-above> is <i>, not <i><dot-above>.
> This only works if the string is NFC-normalised before applying case
> folding.
> 
> 
> [*] Remember that we are applying case folding, not lowercase mapping.
> 
> - -- 
> David Hopwood <david.hopwood@zetnet.co.uk>
> 
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