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Re: [idn] Document Status?
Erik Nordmark <Erik.Nordmark@sun.com> wrote:
> > +----------------------------+
> > | internationalized labels |
> > | |
> > | +----------------+ |
> > | | ASCII labels | |
> > | | | |
> > | | +--------+ | |
> > | | | ACE | | |
> > | | | labels | | |
> > | | +--------+ | |
> > | +----------------+ |
> > +----------------------------+
> >
>
> Hmm - I wonder if putting that picture in the draft would result in
> less confusion.
Maybe, although I must warn you that the above picture is simplified,
and contains a slight lie. The box called "ASCII labels" is really
"labels X such that Nameprep(X) is ASCII". Let's use the phrase
"effectively ASCII labels" for that. An accurate and complete picture
would be:
+-----------------------------------+
| internationalized labels |
| |
| +---------------------------+ |
| | effectively ASCII labels | |
| | | |
| | +--------------+ | |
| | | ASCII labels | | |
| | | | | |
| | | +-----------+----+ | |
| | | | ACE labels | | |
| | | | | | | |
| | | | | | | |
| | | +-----------+----+ | |
| | +--------------+ | |
| +---------------------------+ |
+-----------------------------------+
Unfortunately, the picture is starting to look daunting. The exact
subset relationships between every pair of the various sets is not so
important, as long as you know these two:
* The ASCII labels are a subset of the internationalized labels.
* The ACE labels are a subset of the internationalized labels.
The other things you need to know to make sense of the model, which are
not easily depicted, are:
* For every internationalized label, there is an equivalent ASCII
label. ToASCII can compute it. You need ASCII labels for old or
IDN-unaware protocols.
* For every internationalized label, there is an equivalent non-ACE
label. ToUnicode can compute it. You want non-ACE labels for
display to users.
AMC