Re: [idn] automagic case-insensitive comparisons in the DNS server

[Harald Alvestrand <Harald@Alvestrand.no>]

At 15:01 17/09/2000 +0000, Adam M. Costello wrote:
>I just had a wacky idea relevant to the schemes that store ACE at
>the DNS servers.  It's possible to encode the case of the Unicode
>characters as the case of the ACE characters.  Since DNS servers
>already do case-insensitive comparisons of ASCII host names, they would
>automagically be doing case-insensitive comparisons of international
>host names.

as long as you don't run into the twisty little corners of case, like the 
German double S or the infamous Turkish dotless I, this might have merit.
That is, modify our ACE so that:

- if character Ux2345 is lowercawse, encode it as 8qB-abcdefgh
- if character Ux1234 is uppercase, and Ux2345 is its lowercase,
   encode it as 8qB-ABCDEFGH
- decoding would decode to Ux2345, and would compare equal to Ux2345.
   Only if the original representation was desired would one consult the
   Unicode case tables to find that the uppercase of Ux2345 is Ux1234.

Fun idea - if the number of corner cases where case folding does not lose 
information is small enough that we can ignore those.

--
Harald Tveit Alvestrand, alvestrand@cisco.com
+47 41 44 29 94
Personal email: Harald@Alvestrand.no