From 216ffe9b1cf81f26119f15b9ee04f2fec53592fd Mon Sep 17 00:00:00 2001
From: Wilfred Hughes <me@wilfred.me.uk>
Date: Mon, 1 Jan 2018 11:20:11 +0000
Subject: Better handling of keybindings

Look at all keymaps in global variables, so we don't miss keymaps like
`minibuffer-local-map`. Ignore inherited keybindings. Ignore menu bar
items (I don't find them useful at least).

Refactor global keybinding logic, as the global-map variable means we
don't need to treat global keybindings as a special case.
---
 CHANGELOG.md |  8 ++++++++
 helpful.el   | 44 +++++++++++++++++++++++++-------------------
 2 files changed, 33 insertions(+), 19 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 86d0ca1..4c80085 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,14 @@ values.
 
 Quoted keywords in docstrings are now highlighted.
 
+Smarter handling of keybindings:
+
+* Consider all keymaps, not just `foo-mode-map`.
+* Show keybindings where they are defined, don't show them in keymaps
+  that inherit them.
+* Don't show menu bar items, as they clutter the display (please file
+  a bug if you miss this).
+
 # v0.5
 
 Allow function tracing to be enabled/disabled from Helpful buffers.
diff --git a/helpful.el b/helpful.el
index 19f0fa3..397f490 100644
--- a/helpful.el
+++ b/helpful.el
@@ -850,35 +850,41 @@ buffer."
   (let (keymaps)
     (mapatoms
      (lambda (sym)
-       (when (and
-              (boundp sym)
-              (keymapp (symbol-value sym))
-              (s-ends-with-p "-mode-map" (symbol-name sym)))
+       (when (and (boundp sym) (keymapp (symbol-value sym)))
          (push sym keymaps))))
     keymaps))
 
 (defun helpful--keymaps-containing (command-sym)
+  "Return a list of pairs listing keymap symbols that contain COMMAND-SYM,
+along with the keybindings in each keymap.
+
+We ignore keybindings that are menu items, and ignore keybindings
+from parent keymaps."
   (let (matching-keymaps)
-    ;; Look for this command in all major and minor mode maps.
-    (dolist (keymap (helpful--all-keymap-syms))
-      (let ((keycodes (where-is-internal command-sym
-                                         (list (symbol-value keymap)))))
+    ;; Look for this command in all keymaps.
+    (dolist (keymap-sym (helpful--all-keymap-syms))
+      (let* ((keymap (symbol-value keymap-sym))
+             (keycodes
+              (where-is-internal
+               command-sym (list keymap) nil t))
+             ;; Look up this command in the parent keymap.
+             (parent-keymap (keymap-parent keymap))
+             (parent-keycodes
+              (when parent-keymap
+                (where-is-internal
+                 command-sym (list parent-keymap) nil t))))
+        (setq keycodes
+              ;; Ignore keybindings that we've just inherited from the
+              ;; parent.
+              (-difference keycodes parent-keycodes))
         (when keycodes
-          (push (cons keymap
+          (push (cons keymap-sym
                       (-map #'key-description keycodes))
                 matching-keymaps))))
-    ;; Look for this command in the global map.
-    (let ((keycodes (where-is-internal command-sym
-                                       (list (current-global-map)))))
-      (when keycodes
-        (push (cons 'global
-                    (-map #'key-description keycodes))
-              matching-keymaps)))
     matching-keymaps))
 
 (defun helpful--format-keys (command-sym)
-  "Describe all the keys that call COMMAND-SYM.
-Ensures global keybindings are shown first."
+  "Describe all the keys that call COMMAND-SYM."
   (let (mode-lines
         global-lines)
     (--each (helpful--keymaps-containing command-sym)
@@ -888,7 +894,7 @@ Ensures global keybindings are shown first."
            (format "%s %s"
                    (propertize (symbol-name map) 'face 'font-lock-variable-name-face)
                    key)
-           (if (eq map 'global) global-lines mode-lines)))))
+           (if (eq map 'global-map) global-lines mode-lines)))))
     (setq global-lines (-sort #'string< global-lines))
     (setq mode-lines (-sort #'string< mode-lines))
     (-let [lines (-concat global-lines mode-lines)]
-- 
cgit v1.0