A possible way out (strawman!!!!) would be to say:
- All recipient participants in the experiment MUST agree to ignore case
differences in mailbox names. This has no effect on non-participants, so
we can possibly get consensus for that.
- All code in the experiment MUST use a particular algorithm to generate
the LHS lookup key
(I would suggest toLowerCase(NFC(string) in the C locale) off the top of
my head - but one could also argue for caseFold(NFC(string)) or
NFC(caseFold(string)) - and the people choosing had better know the
difference)
I would strongly recommend that if you're going to do this, you do it using the
same case-folding and normalization algoritms that are used for IDNs. (You can
skip the prep stuff and punycode.)
My reasoning here is that if you have support for EAI you're likely
to have IDN support libraries lying around. Libraries which may or may not
support other normalization and case-folding algorithms.
The case operations referenced are in Unicode 8.0.0 section 5.18 - I
*strongly* recommend actually reading that chapter, and not making the
(invalid) assumption that calling toLower() in some random library will
actually do something compatible with this.
Whereas an IDN library will have something you should be able to trust.
I don't think anything less precise has a chance of being interoperable.
Agreed.
Ned