Re: [idn] Document Status?

["Adam M. Costello" <idn.amc+0@nicemice.net.RemoveThisWord>]

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