Re: [idn] case folding

["Brian W. Spolarich" <briansp@acm.org>]

On Wed, 31 May 2000, Harald Tveit Alvestrand wrote:

| At 08:06 31.05.2000 +0800, James Seng wrote:
| >I suppose we already have consensus that *some* canonicalization has to be
| >done. Case-sensitivity does not work in domain names or any naming system.
| 
| oops.....the Unix file system works perfectly with case sensitivity.

  :-) 

  I guess I'll be a contrarian today.

  In looking over the RFC index, I see a lot of examples of protocols that
tend towards case-insensitivity as the default for comparisons.  These
protocols also tend to do this in the context of plain ASCII characters
(i.e. LDAP v3, RFC2251).  I haven't seen a lot of examples of
case-insensitivity in larger character sets, precisely because of the
complexity involved that we're talking about here.

  What problem does case folding solve?  Is it reasonable for protocol
users to expect that MYDOMAIN.COM and MyDoMaIn.CoM are semantically the
same, and therefore the protocol should understand that?  While there is a
backward compatibility requirement for US-ASCII, is it truly the case that
users of the IDN will so strongly expect this behaviour that it becomes a
requirement?  Is it possible to come up with a case-folding implementation
that is going to satisfy the behavioural expectations of the large
majority of the users?  I am mostly ignorant of these issues as they apply
to the the vast majority of languages, but given the issues that have been
raised here, I have to wonder if this is practically achievable.

  One of the DNS' strengths is its relative simplicity for the complex
distributed task that it accomplishes.  Would the complexity and potential
ambiguity involved in coming up with case mapping rules that meet
everyone's expectations dimish the simplicity priciple that makes the DNS
work well?

  -brian

-- 
 Brian W. Spolarich - Ann Arbor, MI - briansp@acm.org - www.acm.org/~briansp/
        "Wickedness is a myth invented by good people to account for
            the curious attractiveness of others." - Oscar Wilde