Re: [sieve] Question about draft-ietf-sieve-external-lists-02

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> I just gave the latest specification (ietf-02) of the extlists extension
> a quick read. The last version I read was ietf-00 and since then the
> :list argument for the various test commands was changed into an actual
> generic match type. This is, I think, a very good idea.

I'm glad you agree.

> However, the
> document does not describe how this new match type interacts with a
> specified comparator.

Yes, and I'm of two minds as to how to fix it. The simplest thing to do is to
simply declare that comparators have no effect on :list. (We can make them a
no-op or an error to even specify.) The alternative is to allow comparators to
be an input, but for the use of that input to be implementation and
list-specific. (Again, whether or not it would be an error to specify a
comparator on a :list that doesn't consume it would need to be determined.)

I guess what I'd like to see is a use-case where comparators can be  useful
with :list. If such cases exists I'm inclined to allow the combination, if not
I'm inclined to disallow it.

> For example, when I remember correctly, the LDAP
> schema internally defines how, i.e. with what collation, attribute
> values are to be matched.

Exactly so. And it isn't just LDAP - database keys are generally typed, so
:list mapping onto a database is likely to encounter similar issues.

> So, will the specified comparator be ignored
> for LDAP URIs or will it trigger an error? How about other list/db/URI
> types?

Same issue there as well.

> What to do in situations where specifying an explicit comparator
> is inappropriate? I think this is an important issue that should be
> adressed in the specification.

There's also the possibility of doing something akin to how the current regex
draft uses comparators - as a means of identifying a canonicalization and what
constitutes a unit of comparison. Do we want to allow that sort of use with
:list?

				Ned