[PATCH v5 2/3] emacs: add a filter option to show

[Mark Walters <markwalters1009@gmail.com>]

Show the current thread with a different filter (i.e., open messages
in the thread matching the new query).

Bound to 'l' for "limit".

Note that it is not the same as filter in search mode as it replaces
the existing query rather than ANDing with it (but it does keep the
thread-id part of the query).
---
 emacs/notmuch-show.el | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index a978d3c..4dee34b 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -47,6 +47,7 @@
 (declare-function notmuch-tree "notmuch-tree"
 		  (&optional query query-context target buffer-name open-target))
 (declare-function notmuch-tree-get-message-properties "notmuch-tree" nil)
+(declare-function notmuch-read-query "notmuch" (prompt))
 
 (defcustom notmuch-message-headers '("Subject" "To" "Cc" "Date")
   "Headers that should be shown in a message, in this order.
@@ -1372,6 +1373,7 @@ (defvar notmuch-show-mode-map
     (define-key map (kbd "<backtab>") 'notmuch-show-previous-button)
     (define-key map (kbd "TAB") 'notmuch-show-next-button)
     (define-key map "f" 'notmuch-show-forward-message)
+    (define-key map "l" 'notmuch-show-filter-thread)
     (define-key map "r" 'notmuch-show-reply-sender)
     (define-key map "R" 'notmuch-show-reply)
     (define-key map "|" 'notmuch-show-pipe-message)
@@ -1660,6 +1662,16 @@ (defun notmuch-show-command-hook ()
     (save-excursion
       (funcall notmuch-show-mark-read-function (window-start) (window-end)))))
 
+(defun notmuch-show-filter-thread (query)
+  "Filter or LIMIT the current thread based on a new query string.
+
+Reshows the current thread with matches defined by the new query-string."
+  (interactive (list (notmuch-read-query "Filter thread: ")))
+  (let ((msg-id (notmuch-show-get-message-id)))
+    (setq notmuch-show-query-context (if (string= query "") nil query))
+    (notmuch-show-refresh-view t)
+    (notmuch-show-goto-message msg-id)))
+
 ;; Functions for getting attributes of several messages in the current
 ;; thread.
 
-- 
2.1.4