[idn] Re: Document Status?

[Simon Josefsson <jas@extundo.com>]

"Adam M. Costello" <idn.amc+0@nicemice.net.RemoveThisWord> writes:

>     +-----------------------------------+
>     | 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.

Having a larger box called "Unicode strings" outside all of those
boxes would be useful too.  I think the picture, and your discussion
of it, helps alot for the understanding of IDNA.  A daunting picture
conveys the information that IDNA isn't trivial, which is a good mind
set to have when implementing it.