Charles Lindsey writes:
No, that was always allowed, because a dot-atom can always be preceded
by CFWS. But it is a good example of how hard it can be to check some
of these cases in the present syntax.
3. The date syntax is reordered, and four-digit years seem to have
disappeared from the obsolete syntax. This looks like a good idea:
I don't think 4DIGIT was ever in obs-year. Nor even in RFC 822?
Sorry, Pete is right, 2*DIGIT was on the page and my brain was seeing
2DIGIT. 2*DIGIT is perfectly okay.
7. There may be a few cases where FWS in 2822 is replced by CWFS in
Bruce's grammar. It's a little hard to tell. For example, in Bruce's
grammar there always is CFWS following field-name ":", I'm not sure
the same holds for 2822. It may.
Not so. Look at orig-date, for example, where it is explicitly [FWS]
that follows the ":".
Anyway, I think Bruce's stuff is better, because it's easier to read. In
2822 I'd need a long time to be sure where CFWS is permitted (as
opposed to only FWS), in Bruce's grammar it's much easier.