John C Klensin wrote:
I think the big point here is that one can't make _any_
change of this sort lightly. There are almost always
complications.
Sure, but we have enough ABNF experts / fans here, adding
Bill's validator I'm confident that we won't introduce
new "bugs" unintentionally.
In some cases it's a question of "what's less harmful",
you can't allow crap like bare-CR and forbid it at the
same time. If absolutely necessary there's that MUST
accept + MUST NOT generate option.
But that's also where the headaches begin, resulting in
a split ABNF as in 2822 chapter 3 and 4 (obs-cenities
in chapter 4). But obviously it's even then possible
to get it right, maybe we should adopt this example...
I could rant for hours non-stop about 2822, but above
all I admire it of course.
Bye, Frank