<http://www.ietf.org/internet-drafts/draft-degener-sieve-copy-00.txt>
fileinto :copy, redirect :copy -- keyword parameter that
prevents cancelling the implicit "keep".
That is certainly useful.
The Exim filter uses "seen" and "unseen" deliveries. If any seen
deliveries take place, there is no implicit keep. Each delivery of a
message has a default of being seen or unseen, that can be changed using
an option. "seen" is like "discard", "unseen" is like ":copy".
I would prefer if the draft expressed more clearly that "keep" is not
symmetric to "discard", because keep stores the message, whereas discard
just clears the implicit keep. In fact, RFC 3028 could be more clear
on that issue. It gives a better motivation why ":copy" is needed, though.
Do we need a way to set the implicit keep flag? I can't think why right
now; it just looks not symmetric that it can be reset or left alone, but
not set.
Michael