[notmuch] notmuch_threads_back and notmuch_messages_back

[Carl Worth]

On Thu, 26 Nov 2009 21:23:47 +0100, Ruben Pollan <meskio at sindominio.net> wrote:
> Is it possible to implement notmuch_threads_back and notmuch_messages_back?
> And I guess will make sense to have also notmuch_tags_back.
> 
> This functions will do the oposite than notmuch_threads_advance and
> notmuch_messages_advance. So I can use them as iterators going back and forward.
> 
> I didn't check the implementation of notmuch. I don't know if will be easy or
> will need to redesign a lot of code.

Most cases of these iterators are built on Xapian iterators, (C++ objects with
overloaded operators). So those are just using ++ for advance() and can
easily use -- for the new function, (I'd like a verb that pairs better
with "advance" than the non-verb "back"---any suggestions)?

So those won't need any new code. The one case that will need new code
is that for notmuch_message_get_replies and
notmuch_message_get_toplevel_messages the messages iterator is currently
built on a singly-linked list. Making it doubly linked would obviously
not be hard though.

-Carl