Re: [idn] case folding

[Maurizio Codogno <mau@beatles.cselt.it>]

RJ Atkinson wrote in <4.2.0.58.20000530092821.0098e100@avarice.inner.net>:

> >What about saying that the only case folding is [A-Z][a-z], for backward
> >compatibility with present DNS?
> 
> This would create a disaster between lower-case Vietnamese d- and upper-case
> Vietnamese D- with respect to URLs containing that character.  Many other
> examples exist in many languages.

it depends. I agree that it's not the best thing in the world to
allow that caffè.it (with `e) and CAFFÈ.it (with `E) are both assigned
to different people, but I don't know if the Principle of Least 
Astonishment says that if the URL is given to you in lowercase you
can digit it UPPERCASE. Even RFC1034 said that "When you receive a 
domain name or label, you should preserve its case"... It would be 
a mess to enforce this in ASCII, but we can adopt it for the extensions.
Another alternative for *alphabetic* characters besides ASCII is to 
forbid use of uppercase letters, so that upper Greek Alpha is not allowed,
but this seems a mess anyway... this is maybe because I do not know 
Unicode very well. Am I at least correct in inferring that the variant
forms of letter in Arabic are just variant, so they give no problem? 

For non-alphabetic characters I cannot say nothing, since it's all 
Chinese to me :-)

ciao, .mau.