[idn] Adding "optional" characters in draft-ietf-idn-nameprep

[Paul Hoffman / IMC <phoffman@imc.org>]

Jonathan Rosenne pointed out that we might need another class of 
characters for processing. Hebrew vowels are optional characters that 
some people enter, although most don't. There are probably a few such 
characters in other written scripts as well. We have a few choices:

a) We can ignore these characters on input (that is, toss them out of 
the input stream).

b) We can prohibit the characters on input.

c) We can allow them in names. This would mean that people 
registering names would have to register them with and without the 
characters (possibly in many combinations).

UI issues:
(a) would be easiest for users because they don't have to remember 
whether or not to use the characters. (b) would cause users who enter 
them in names to get an error that says an illegal character was 
entered. (c) would also be easy for users, but only if name holders 
register all logical possibilities of the names.

Complexity in nameprep:
(a) adds another step and another table to the nameprep, although the 
table will be small. (b) will be easiest because we already have a 
table of prohibited characters. (c) adds no complexity.

Registration of names:
(a) and (b) allows the registration of the fewest names, that is, 
without the optional characters. (c) would require that name owners 
register all names that include the optional characters.

Comments? Favorites?

--Paul Hoffman, Director
--Internet Mail Consortium