second, because the code necessary to do normalization and encoding
will be available in libraries that everyone can use - the MUA vendor
won't have to get that part right.
Do you really think Bill Gates is going to lower himself to using code
written by somebody else? No, he will cut his own and get it wrong
(probably deliberately) :-( .
what we think Bill Gates will or will not do is not a sane basis for
making a technical decision on a standard.
and of course the normalization would have to be done even with pure UTF-8.
the ASCII encoding step is fairly simple and isn't likely to introduce
many errors.
Not necessarily for normalization (NFC or NFKC). That is a job for
keyboard drivers and other features of the operating system.
do you really think that OS vendors are going to rewrite *every* form
of input (not just keyboard drivers but copy-and-paste, files downloaded
from the net, etc) to do normalization? if they did, it would break
far more things than it would fix.
It should
normally be possible for people to write applications (and MUAs are
applications) on the assumption that all the string in the system are
already normalized.
it's possible to write applications with those assumptions. of course,
they won't work reliably, because you can't control every possible input.
Keith