> There is a Default Unicode Collation Element Table (DUCET) that defines,

> well, the default Unicode collation. But it is only the default. A
> collation designed can implement any rules he or she wanted to.

Am I right in thinking that you are proposing a setup similar to collation
in MySQL 4.1+ for Nimbus? Perhaps based on the ICU library reference
implementation?

With reference to your original post, I would personally probably hard
code the DUCET tables and only make the customizations loadable, as my
perception is that the base tables are large and that the customizations
are small. The equality levels are an interesting thought, but perhaps
better handled via a function (i.e. upcase(str1)==upcase(str2), or
l1(str1)==l1(str2))?

I'm not deeply into collations, but it seems to me you are on the right
track.

Paul