> What's the advantage to adding this to the library?  Why not just
> notmuch_query_search_messages, iterate over the messages and use
> notmuch_message_get_header(msg, "from") to accumulate the author
> information, and then output that?  Unless I'm overlooking something
> (which is possible), there are no algorithmic advantages to doing this
> in the library.


The view I have in mind would look something like:

John Doe (1234 msg)
|- first thread subject
|- second thread subject
|- third thread subject
Jane Doe (234 msg)
|- first thread subject
|- second thread subject
|- third thread subject
...


The problem is, that if I want to have a list of all authors in the database I'd
have to iterate over all messages (naively implemented, whenever I render the
view, or I somehow have to persistently store this list and update it on a
regular basis), whereas the notmuch database already has this information but
doesn't reveal if I'm not overlooking something. To do a
notmuch_query_search_messages I'd have to know what to search for, whereas a
notmuch_database_get_all_authors would give me exactly what I'm looking for in
short time since it is already indexed by xapian.

Best,
Johannes