I guess the only ones interested in this is server authors / maintainers
and administrators. We can rephrase it a bit, stating that two dots means
one, and one dot means the hierarchy seperator, and that this is to be
interpreted left to right, leftmost derivative..
And the users! Someone _will_ try to make mailbox 'misc', and then try to make '...crap' under it. Never underestimate the users' ability to come up with strange edge-case scenarios :-)
The above case would not be possible to encode in IMAPdir, even though the hierarchy delimiter has not been used. This would generally not be a problem ('...crap' is pretty weird, really), except that literal dots at the very beginning of the mailbox name (at the root of the tree) *are* allowed.
How about a separate escape character? Instead of overloading the dot to mean three things (escape, literal, separator), have:
\ (escape char) \\ (literal \) . (hierarchy delimiter) \. (literal dot)
I am talking about the IMAPdir representation, of course, not about the imap side of things. The only thing that is a little tricky is that '\' is already an escape character in most (all?) unix shells, so anyone modifying their IMAPdirs by hand will need to use single quotes or double-escape their backslashes.
This wouldn't change the leading dot special case, it would remain a literal dot, regardless of wether it is escaped or not.
-Dan
