david.goldberg6@verizon.net (Dave Goldberg) writes:

>> Hello,
>> I use a tool called mu [1] to index and search my mail, which is stored
>> in a Maildir folder. mu is able to give me the message ids of all the
>> mails that match a given query. I want to use these ids to create a new
>> group in gnus that shows the search result. So it basically boils down
>> to this:
>
>> Is there a function or facility in gnus that takes a list of message-ids
>> (or even a list of local path names) and creates a new group containing
>> the corresponding messages?
>
>> I am fine with writing some elisp to call out to mu and converting its
>> output to a list, I just need above mentioned functionality.
>
> nnir.el provides an interface to various search capabilities and although I
> can't speak to it as I don't use it, I see maildir mentioned for one of the
> backends.  Perhaps that is enough to get you started.

I while back I wanted exactly this. It's a work in progress; to be frank
I don't remeber if I ever for it working, as I switched away from
maildir and consequently mu. Worth a shot!

--8<---------------cut here---------------start------------->8---
(require 'nnir)

(defcustom nnir-mu-program "mu"
  "*Name of mu indexing program."
  :type '(string)
  :group 'nnir)

(defcustom nnir-mu-additional-switches '()
  "*A list of strings, to be given as additional arguments to mu.

Note that this should be a list.  Ie, do NOT use the following:
    (setq nnir-mu-additional-switches \"-s date -z\") ; wrong
Instead, use this:
    (setq nnir-mu-additional-switches '(\"-s\" \"date\" \"-z\"))"
  :type '(repeat (string))
  :group 'nnir)

(defun nnir-run-mu (query server &optional group)
  "Run QUERY against mu.
Returns a vector of (group name, file name) pairs (also vectors,
actually)."
  (save-excursion
    (let ((qstring (cdr (assq 'query query)))
          (groupspec (car group))
          artlist)

      (when (equal "" qstring)
        (error "mu: You didn't enter anything"))

      (set-buffer (get-buffer-create nnir-tmp-buffer))
      (erase-buffer)

      (if groupspec
          (message "Doing mu query %s on %s..." qstring groupspec)
        (message "Doing mu query %s..." qstring))

      (let* ((cp-list `( ,nnir-mu-program
                         nil            ; input from /dev/null
                         t              ; output
                         nil            ; don't redisplay
                         "find"
                         "--format=sexp"
                         ,@(nnir-read-server-parm 'nnir-mu-additional-switches server)
                         ,@(split-string qstring "\\s-+")       ; the query, in mu format
                         ))
             (exitstatus
              (progn
                (message "%s args: %s" nnir-mu-program
                         (mapconcat 'identity (cddddr cp-list) " ")) ;; ???
                (apply 'call-process cp-list))))
        (unless (or (null exitstatus)
                    (zerop exitstatus))
          (nnheader-report 'nnir "Couldn't run mu: %s" exitstatus)
          ;; mu failure reason is in this buffer, show it if
          ;; the user wants it.
          (when (> gnus-verbose 6)
            (display-buffer nnir-tmp-buffer))))

      ;; The results are output in the format of:
      ;; plists
      (goto-char (point-min))
      (while (not (eobp))
        (ignore-errors
          (let* ((item (read (current-buffer)))
                 (group (concat server ":" (substring (plist-get item :maildir) 1)))
                 (artno (plist-get item :docid))
                 (score 1000))
            (push (vector group artno score) artlist))))

      (message "Massaging mu output...done")
      (print artlist)
      artlist)))

(add-to-list 'nnir-engines '(mu nnir-run-mu ()))
--8<---------------cut here---------------end--------------->8---
--
Pedro