Re: Matching and comparison

[Harald Tveit Alvestrand <Harald@Alvestrand.no>]

At 14:44 23.01.00 +0800, James Seng wrote:

>Speaking for my own, and solely for my own, I have an interest to see what
>difficulties and whether a ISO2022-X + ISO8859-X integrated solution (like how
>MULE has done) is viable. I would like to work on this if I have the time...or
>at least see someone else attempt to do it.
See Ohta's various documents and the popular receptions they have had.
In particular RFC 1554.

The problems with an ISO 2022 character set switching approach are 
numerous, intractable and quite, quite horrid.

Quick question: Does ESC ( K A B C mean or not mean the same as ESC ) K A B C?

Answer: It depends on your initial state......

Next question: Does "OU=" ESC ( K A B C ";O=" A B C mean that OU and O have 
the same value or not?

Answer: It depends on whether you ASN.1 encode a 2022 string or 2022 encode 
an ASN.1 string.....

See also ITU recommendations X.680++ for how much of a mess they made out 
of GeneralText by using ISO 2022 switching. I still get hit by the 
occasional bug report based on improper implementation of this switching 
mechanism.

Don't go there. It's bad.

                   Harald
--
Harald Tveit Alvestrand, EDB Maxware, Norway
Harald.Alvestrand@edb.maxware.no