Re: [idn] Newbie's questions implementing the [IDNA]

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

On Tue, Dec 10, 2002 at 12:29:46AM +0000, Adam M. Costello wrote:
> Soobok Lee <lsb@postel.co.kr> wrote:
> 
> > > The output of ToUnicode can contain unnameprepped, prohibited, and
> > > unassigned code points.  Simply feed such a string as input to
> > > ToUnicode, and the string will be output unaltered by ToUnicode.
> >
> > right. IDNA states that such outputs should not be displayed as native
> > ones, but just as ASCII ones as it is. "must not" is meant for that.
> > I think it is clear enough in drafts.
> 
> I don't know what you could be referring to.  Suppose X is a string
> consisting entirely of uppercase Greek letters.  X is not nameprepped,
> because nameprepped things don't contain uppercase.  X contains no ASCII
> characters.  ToUnicode(X) equals X, exactly, which means it is perfectly
> acceptable to display X.

I mean that Punycode(X) [not Punycode(NAMEPREP(X)), not X ] can be inserted into 
 RFC822 message headers. In that case, ToUnicode(Punycode(X)) should be 
treated differently than ToUnicode(Punycode(Nameprep(X))) .

You are right if X is non-ASCII input, because toUnicode(X)==X.

> 
> AMC