ietf-mta-filters
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Re: Multiple actions in Sieve script.

1999-01-22 00:54:17
I'd like to put aside the question of MultipleFileInto for a moment.
The reliability required for Sieve scripts has been declared to be
sufficiently low that MultipleFileInto may represent a considerable
burden to implementors (you *must* lock mailboxes while delivering and
*must* not screw it up).  I don't care about this, but I think the
question can wait until we nail down the question of filing into two
mailboxes.


I think the copyinto/fileinto situation is very ugly because it involves 
a set of semantics that may prevent anyone from getting hurt but also
prevent anyone from being able to comprehend a Sieve script without
trying to decipher them.  We will have lots of hidden semantics that
will not make sense at first glance.

FLAMES lacked an implicit keep and users did not lose mail.  What they
did was they had LISP programs that had a cond form (it's like an
if/elsif/else chain) that the last form always said "If all else fails,
just keep it."

So let's dump the implicit keep.  We're still arguing about it, no one
will ever understand it, it's hard to explain, it's hard to decide when
it shouldn't happen, and it's not going to save anyone.

I haven't yet come up with a set of keep semantics that make any sense.

Once we do that, we can have two commands, one which is a
single-fileinto and one which allows a multiple-fileinto, make keep a
special case of single-fileinto, and be done with it.

(We can add a all-or-nothing multiple-fileinto on top of that.  I
believe we can argue them seperately.)

Tim

-- 
Tim Showalter <tjs+(_at_)andrew(_dot_)cmu(_dot_)edu>