Re: Character equivalence mapping (was: Re: [idn] SLC minutes)

[tedd <tedd@sperling.com>]

To whomever:

Some time ago, I argued (see below) that the 
current version (at that time) of nameprep mapped 
upper case Greek Letters to lower case.

My comments were basically dismissed as "That's 
the way we do it, get used to it!"

Now, I find that the current version of PUNNYCODE 
does exactly the opposite than what was claimed. 
For example, try entering the code point 2126 
(upper case Omega) through --

http://www.imc.org/idna/do-idna.cgi

-- and see what happens. The end result is uppercase and NOT lowercase.

Is this the "new way" to resolve the old issue 
discussed? Has the "powers that be" reversed 
themselves or did I find an error in PUNNYCODE?

Many thanks for any replies.

tedd

--- as previously stated on this list in January 2002 ---

Mark, john, Edmon:

> 1. This issue was debated at length some time ago. I suggest that the people
> arguing for visual confusability as a criterion for matching look at that
> discussion in detail before proceding.

I'm not arguing (in this debate) the 
"look-a-like" position. In other words, it makes 
no difference to me if certain glyph's look 
identical in numerous char sets. I am arguing the 
opposite position -- the characters in my example 
don't look a like.

I am arguing the point that the decision "has 
been made" to map upper case Greek letters to 
lower case letters. For proof, look at the 
current version of nameprep ( 
http://www.imc.org/nameprep/  ) and try running 
code point 2126 (upper case omega) through it. 
You will find that it IS mapped to code point 
03A9 (lower case omega).

My question is "Why?" What's the foundation for 
this determination? For what good reason is there 
to conclude that the upper case Omega should be 
mapped to a lower case omega?

I see no "A.com" to  "a.com" argument/problem 
here. Clearly, if someone registered ?.com and 
someone else registered w.com there is 
significant difference in identification between 
the two names. Those two domain names can be 
completely unique domain names with no 
significant resultant problems. Whereas, in the 
Latin char set, I can see the reason for making 
W.com and w.com identical (i.e., mapping W to w) 
because there is an UC/LC 
consideration/distinction in the language. But, 
that's not a problem in the Greek char set -- is 
it... really?

> (i) From observation, when scripts have two cases, the
> upper-case form is more likely to be highly stylized, and hence
> differentiated from characters in other scripts, than the
> lower-case one.  Hence, if one is going to adopt
> stylization-based (glyph-distinction, if you prefer)
> canonicalization rules, one is better off treating upper case as
> the normal form, rather than lower case.

It looks to me as if someone has already made the 
determination to map other languages based upon 
the Latin char set UC/LC problem without concern 
that other languages may not have the UC/LC 
distinction and thus be absent of the UC/LC 
problem. I think the Greek example I gave above 
sufficiently demonstrates my observation.

tedd

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