A hypothetical extension

[Dave Cridland <dave@xxxxxxxxxxxx>]

Let's define a hypothetical extension to LIST-EXTENDED:

It has a return option RECENT, which returns the recent count of a 
mailbox.

It also has a "base" selection option RECENT, which restricts the 
selection to mailboxes which have a non-zero recent message count. 
Being a base option, it means that this may be used with 
RECURSIVEMATCH. We'll make it imply the RECENT return option, as is 
traditional.

Now... What I'd like to do with this extension is show my GUI tree 
control of mailboxes which are subscribed, with little expander 
buttons for those that have subscribed children, and also highlight 
those mailboxes which have recent messages - or subscribed children 
which have recent messages.

In other words, assuming:

A01 LIST (SUBSCRIBED) "" "*" RETURN (RECENT)
* LIST (\Subscribed \UnMarked) "/" Foo
* LIST (\Subscribed \Marked) "/" Foo/Bar/Baz ((RECENT "24"))
* LIST (\Subscribed \Marked) "/" Zab ((RECENT "42"))
* LIST (\Subscribed \UnMarked) "/" Boring
A01 OK

Then I want to show Foo, Zab, and Boring. Foo and Zab will both be 
highlighted, Boring will not be. Zab will have a recent count 
displayed next to it.

In order to do this, I need to:

B01 LIST (SUBSCRIBED RECURSIVEMATCH) "" "%"
B02 LIST (SUBSCRIBED RECENT RECURSIVEMATCH) "" "%"

B01 here gets the mailbox listing and the tree "expander" 
information. B02 gets the highlighting information. The server has to 
recusrively search twice.

What I'd really like to do, though, is the imaginary syntax:

C01 LIST (SUBSCRIBED RECURSIVEMATCH (SUBSCRIBED) RECURSIVEMATCH 
(SUBSCRIBED RECENT)) "" "%" RETURN (RECENT)

In other words, "Tell me all the subscribed mailboxes at the top 
level, and also include CHILDINFO blocks for SUBSCRIBED and 
SUBSCRIBED+RECENT".

I can think of more use-cases for this than for multiple mailbox 
patterns, incidentally.

From the server's perspective, it now has to perform the recursive 
mailbox search only once through, rather than twice, which seems more 
efficient.

Is this worth considering at this late stage?

Dave.
--
          You see things; and you say "Why?"
  But I dream things that never were; and I say "Why not?"
   - George Bernard Shaw