[PATCH 1/1] emacs: add '?' to some prefix keymaps to describe its bindings

[Tomi Ollila]

Added (private) function `notmuch--prefix-bindings' which wraps
`describe-prefix-bindings' to provide more suitable user interface for
showing the key sequences that follow a particular notmuch prefix
keymap invocation.

The key '?' in prefix keymaps `notmuch-search-stash-map',
`notmuch-show-stash-map' and `notmuch-show-part-map' is bound to this
function via `lambda' expression. By using this lambda expression the
pop-up binding description window shows '??' instead of
`notmuch--prefix-bindings' for the binding of '?' -- which suits our
needs perfectly.
---
 emacs/notmuch-lib.el  | 9 +++++++++
 emacs/notmuch-show.el | 2 ++
 emacs/notmuch.el      | 1 +
 3 files changed, 12 insertions(+)

diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
index 4796f17..8191aec 100644
--- a/emacs/notmuch-lib.el
+++ b/emacs/notmuch-lib.el
@@ -553,6 +553,15 @@ status."
        (message "%s" (error-message-string err))))
     (ignore-errors (delete-file err-file))))
 
+(defun notmuch--prefix-bindings ()
+  "Notmuch private wrapper for `describe-prefix-bindings'."
+  ;;(interactive)
+  (describe-prefix-bindings)
+  (pop-to-buffer "*Help*") ; XXX that's what describe-bindings-internal uses
+  (let ((buffer-read-only nil))
+    (goto-char (point-min))
+    (insert "\nPress 'q' to quit this window.\n\n")))
+
 ;; This variable is used only buffer local, but it needs to be
 ;; declared globally first to avoid compiler warnings.
 (defvar notmuch-show-process-crypto nil)
diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 82b70ba..98bf3d4 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -1248,6 +1248,7 @@ reset based on the original query."
     (define-key map "t" 'notmuch-show-stash-to)
     (define-key map "l" 'notmuch-show-stash-mlarchive-link)
     (define-key map "L" 'notmuch-show-stash-mlarchive-link-and-go)
+    (define-key map "?" (lambda () (interactive) (notmuch--prefix-bindings)))
     map)
   "Submap for stash commands")
 (fset 'notmuch-show-stash-map notmuch-show-stash-map)
@@ -1258,6 +1259,7 @@ reset based on the original query."
     (define-key map "v" 'notmuch-show-view-part)
     (define-key map "o" 'notmuch-show-interactively-view-part)
     (define-key map "|" 'notmuch-show-pipe-part)
+    (define-key map "?" (lambda () (interactive) (notmuch--prefix-bindings)))
     map)
   "Submap for part commands")
 (fset 'notmuch-show-part-map notmuch-show-part-map)
diff --git a/emacs/notmuch.el b/emacs/notmuch.el
index f3ce840..3a115c8 100644
--- a/emacs/notmuch.el
+++ b/emacs/notmuch.el
@@ -245,6 +245,7 @@ For a mouse binding, return nil."
 (defvar notmuch-search-stash-map
   (let ((map (make-sparse-keymap)))
     (define-key map "i" 'notmuch-search-stash-thread-id)
+    (define-key map "?" (lambda () (interactive) (notmuch--prefix-bindings)))
     map)
   "Submap for stash commands")
 (fset 'notmuch-search-stash-map notmuch-search-stash-map)
-- 
1.8.0