Re: Sieve extension to expire mails?

Michael Haardt writes:
> The idea of a folder property versus a message property is 
> interesting, but indeed I thought about a folder property to be 
> specified by Sieve. Expiring mails on delivery is way more efficient 
> than daily jobs, because on many systems (e.g. maildir) the folder 
> contents are already in the page cache. Sieve, as MDA filter, 
> controls local delivery on my systems and if local delivery includes 
> expiration, it feels natural to control that, too.
Sieve, as a language/protocol, must be held to stricter standards than 
any single implementation.
If sieve makes the promise that a a mailbox should contain only the past 
seven days' mail, users might reasonably rely on that. If, then, no 
mail is delivered in seven days, the mailbox should STILL contain the 
past seven days' mail (that is, it should be empty). If expiry happens 
as part of delivery, older mail will still be retrievable.
If your implementation confuses delivery and expiry, that's okay. You 
have a privacy/security issue, that's all. But if the sieve language 
confuses them, all implementations do. Much worse.
FWIW, I also don't like the idea of sieve managing folder properties. 
That seems to be out of scope for sieve.
Arnt