Skip intermediate mbox file in mail-sources?

[David Z Maze <dmaze@MIT.EDU>]

I was tracking down some issues[1] with sucking in my mail today, and
was wondering why Gnus does this:

  (1) Open mail source.  Read one message at a time.  Concatenate into
      a single mbox file ($HOME/.emacs-mail-crash-box, then copied
      into Incomingxxxxxx.)

  (2) Open the mbox file.  Parse out a message at a time, and call the
      function named in nnmail-split-method on each.

Is there a reason the intermediate mbox file is necessary?  (I could
entirely believe that, once upon a time, GNUS only grokked mbox
format, and "translate anything to mbox" was the easiest way to add
more mail sources.)  With formats like directory, pop, maildir, and
imap, where you can readily fetch a message at a time, this adds an
unnecessary layer of indirection.  This also results in side effects:
From at the start of the line gets the ugly mbox quoting, which really
shouldn't be necessary unless the backend is also in mbox format.

-- 
David Maze             dmaze@mit.edu          http://www.mit.edu/~dmaze/
"Theoretical politics is interesting.  Politicking should be illegal."
	-- Abra Mitchell