1 files changed, 143 insertions, 165 deletions

diff --git a/lisp/help.el b/lisp/help.el
index db76efb01a0..34b1a2fac61 100644
--- a/lisp/help.el
+++ b/lisp/help.el
@@ -309,7 +309,7 @@ If that doesn't give a function, return nil."
 The prefix described consists of all but the last event
 of the key sequence that ran this command."
   (interactive)
-  (let* ((key (this-command-keys)))
+  (let ((key (this-command-keys)))
     (describe-bindings
      (if (stringp key)
          (substring key 0 (1- (length key)))
@@ -535,28 +535,6 @@ If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
           (princ string)))))
   nil)
 
-(defun string-key-binding (key)
-  "Value is the binding of KEY in a string.
-If KEY is an event on a string, and that string has a `local-map'
-or `keymap' property, return the binding of KEY in the string's keymap."
-  (let* ((defn nil)
-         (start (when (vectorp key)
-                  (if (memq (aref key 0)
-                            '(mode-line header-line left-margin right-margin))
-                      (event-start (aref key 1))
-                    (and (consp (aref key 0))
-                         (event-start (aref key 0))))))
-         (string-info (and (consp start) (nth 4 start))))
-    (when string-info
-      (let* ((string (car string-info))
-             (pos (cdr string-info))
-             (local-map (and (>= pos 0)
-                             (< pos (length string))
-                             (or (get-text-property pos 'local-map string)
-                                 (get-text-property pos 'keymap string)))))
-        (setq defn (and local-map (lookup-key local-map key)))))
-    defn))
-
 (defun help-key-description (key untranslated)
   (let ((string (key-description key)))
     (if (or (not untranslated)
@@ -589,11 +567,14 @@ temporarily enables it to allow getting help on disabled items and buttons."
              (menu-bar-update-yank-menu "(any string)" nil))
            (setq key (read-key-sequence "Describe key (or click or menu item): "))
            ;; If KEY is a down-event, read and discard the
-           ;; corresponding up-event.
-           (if (and (vectorp key)
-                    (eventp (elt key 0))
-                    (memq 'down (event-modifiers (elt key 0))))
-               (read-event))
+           ;; corresponding up-event.  Note that there are also
+           ;; down-events on scroll bars and mode lines: the actual
+           ;; event then is in the second element of the vector.
+           (and (vectorp key)
+                (let ((last-idx (1- (length key))))
+                  (and (eventp (aref key last-idx))
+                       (memq 'down (event-modifiers (aref key last-idx)))))
+                (read-event))
            (list
             key
             (if current-prefix-arg (prefix-numeric-value current-prefix-arg))
@@ -604,46 +585,33 @@ temporarily enables it to allow getting help on disabled items and buttons."
          (fset 'yank-menu (cons 'keymap yank-menu))))))
   (if (numberp untranslated)
       (setq untranslated (this-single-command-raw-keys)))
-  (save-excursion
-    (let ((modifiers (event-modifiers (aref key 0)))
-          (standard-output (if insert (current-buffer) t))
-          window position)
-      ;; For a mouse button event, go to the button it applies to
-      ;; to get the right key bindings.  And go to the right place
-      ;; in case the keymap depends on where you clicked.
-      (if (or (memq 'click modifiers) (memq 'down modifiers)
-              (memq 'drag modifiers))
-          (setq window (posn-window (event-start (aref key 0)))
-                position (posn-point (event-start (aref key 0)))))
-      (if (windowp window)
-          (progn
-            (set-buffer (window-buffer window))
-            (goto-char position)))
-      ;; Ok, now look up the key and name the command.
-      (let ((defn (or (string-key-binding key)
-                      (key-binding key t)))
-            key-desc)
-        ;; Handle the case where we faked an entry in "Select and Paste" menu.
-        (if (and (eq defn nil)
-                 (stringp (aref key (1- (length key))))
-                 (eq (key-binding (substring key 0 -1)) 'yank-menu))
-            (setq defn 'menu-bar-select-yank))
-        ;; Don't bother user with strings from (e.g.) the select-paste menu.
-        (if (stringp (aref key (1- (length key))))
-            (aset key (1- (length key)) "(any string)"))
-        (if (and (> (length untranslated) 0)
-                 (stringp (aref untranslated (1- (length untranslated)))))
-            (aset untranslated (1- (length untranslated))
-                  "(any string)"))
-        ;; Now describe the key, perhaps as changed.
-        (setq key-desc (help-key-description key untranslated))
-        (if (or (null defn) (integerp defn) (equal defn 'undefined))
-            (princ (format "%s is undefined" key-desc))
-          (princ (format (if (windowp window)
-                             "%s at that spot runs the command %s"
-                           "%s runs the command %s")
-                         key-desc
-                         (if (symbolp defn) defn (prin1-to-string defn)))))))))
+  (let* ((event (if (and (symbolp (aref key 0))
+                         (> (length key) 1)
+                         (consp (aref key 1)))
+                    (aref key 1)
+                  (aref key 0)))
+         (modifiers (event-modifiers event))
+         (standard-output (if insert (current-buffer) t))
+         (mouse-msg (if (or (memq 'click modifiers) (memq 'down modifiers)
+                            (memq 'drag modifiers)) " at that spot" ""))
+         (defn (key-binding key t))
+         key-desc)
+    ;; Handle the case where we faked an entry in "Select and Paste" menu.
+    (if (and (eq defn nil)
+             (stringp (aref key (1- (length key))))
+             (eq (key-binding (substring key 0 -1)) 'yank-menu))
+        (setq defn 'menu-bar-select-yank))
+    ;; Don't bother user with strings from (e.g.) the select-paste menu.
+    (if (stringp (aref key (1- (length key))))
+        (aset key (1- (length key)) "(any string)"))
+    (if (and (> (length untranslated) 0)
+             (stringp (aref untranslated (1- (length untranslated)))))
+        (aset untranslated (1- (length untranslated)) "(any string)"))
+    ;; Now describe the key, perhaps as changed.
+    (setq key-desc (help-key-description key untranslated))
+    (if (or (null defn) (integerp defn) (equal defn 'undefined))
+        (princ (format "%s%s is undefined" key-desc mouse-msg))
+      (princ (format "%s%s runs the command %S" key-desc mouse-msg defn)))))
 
 (defun describe-key (&optional key untranslated up-event)
   "Display documentation of the function invoked by KEY.
@@ -673,109 +641,119 @@ temporarily enables it to allow getting help on disabled items and buttons."
            (list
             key
             (prefix-numeric-value current-prefix-arg)
-            ;; If KEY is a down-event, read the corresponding up-event
-            ;; and use it as the third argument.
-            (if (and (vectorp key)
-                     (eventp (elt key 0))
-                     (memq 'down (event-modifiers (elt key 0))))
-                (read-event))))
+            ;; If KEY is a down-event, read and discard the
+            ;; corresponding up-event.  Note that there are also
+            ;; down-events on scroll bars and mode lines: the actual
+            ;; event then is in the second element of the vector.
+            (and (vectorp key)
+                 (let ((last-idx (1- (length key))))
+                   (and (eventp (aref key last-idx))
+                        (memq 'down (event-modifiers (aref key last-idx)))))
+                 (or (and (eventp (aref key 0))
+                          (memq 'down (event-modifiers (aref key 0)))
+                          ;; However, for the C-down-mouse-2 popup
+                          ;; menu, there is no subsequent up-event.  In
+                          ;; this case, the up-event is the next
+                          ;; element in the supplied vector.
+                          (= (length key) 1))
+                     (and (> (length key) 1)
+                          (eventp (aref key 1))
+                          (memq 'down (event-modifiers (aref key 1)))))
+                 (read-event))))
        ;; Put yank-menu back as it was, if we changed it.
        (when saved-yank-menu
          (setq yank-menu (copy-sequence saved-yank-menu))
          (fset 'yank-menu (cons 'keymap yank-menu))))))
   (if (numberp untranslated)
       (setq untranslated (this-single-command-raw-keys)))
-  (save-excursion
-    (let ((modifiers (event-modifiers (aref key 0)))
-          window position)
-      ;; For a mouse button event, go to the button it applies to
-      ;; to get the right key bindings.  And go to the right place
-      ;; in case the keymap depends on where you clicked.
-      (if (or (memq 'click modifiers) (memq 'down modifiers)
-              (memq 'drag modifiers))
-          (setq window (posn-window (event-start (aref key 0)))
-                position (posn-point (event-start (aref key 0)))))
-      (when (windowp window)
-            (set-buffer (window-buffer window))
-        (goto-char position))
-      (let ((defn (or (string-key-binding key) (key-binding key t))))
-        ;; Handle the case where we faked an entry in "Select and Paste" menu.
-        (if (and (eq defn nil)
-                 (stringp (aref key (1- (length key))))
-                 (eq (key-binding (substring key 0 -1)) 'yank-menu))
-            (setq defn 'menu-bar-select-yank))
-        (if (or (null defn) (integerp defn) (equal defn 'undefined))
-            (message "%s is undefined" (help-key-description key untranslated))
-          (help-setup-xref (list #'describe-function defn) (interactive-p))
-          ;; Don't bother user with strings from (e.g.) the select-paste menu.
-          (if (stringp (aref key (1- (length key))))
-              (aset key (1- (length key)) "(any string)"))
-          (if (and untranslated
-                   (stringp (aref untranslated (1- (length untranslated)))))
-              (aset untranslated (1- (length untranslated))
-                    "(any string)"))
-          (with-output-to-temp-buffer (help-buffer)
-            (princ (help-key-description key untranslated))
-            (if (windowp window)
-                (princ " at that spot"))
-            (princ " runs the command ")
-            (prin1 defn)
-            (princ "\n   which is ")
-            (describe-function-1 defn)
-            (when up-event
-              (let ((type (event-basic-type up-event))
-                    (hdr "\n\n-------------- up event ---------------\n\n")
-                    defn sequence
-                    mouse-1-tricky mouse-1-remapped)
-                (setq sequence (vector up-event))
-                (when (and (eq type 'mouse-1)
-                           (windowp window)
+  (let* ((event (aref key (if (and (symbolp (aref key 0))
+                                   (> (length key) 1)
+                                   (consp (aref key 1)))
+                              1
+                            0)))
+         (modifiers (event-modifiers event))
+         (mouse-msg (if (or (memq 'click modifiers) (memq 'down modifiers)
+                            (memq 'drag modifiers)) " at that spot" ""))
+         (defn (key-binding key t))
+         defn-up defn-up-tricky ev-type
+         mouse-1-remapped mouse-1-tricky)
+
+    ;; Handle the case where we faked an entry in "Select and Paste" menu.
+    (when (and (eq defn nil)
+               (stringp (aref key (1- (length key))))
+               (eq (key-binding (substring key 0 -1)) 'yank-menu))
+      (setq defn 'menu-bar-select-yank))
+    (if (or (null defn) (integerp defn) (equal defn 'undefined))
+        (message "%s%s is undefined"
+                 (help-key-description key untranslated) mouse-msg)
+      (help-setup-xref (list #'describe-function defn) (interactive-p))
+      ;; Don't bother user with strings from (e.g.) the select-paste menu.
+      (when (stringp (aref key (1- (length key))))
+        (aset key (1- (length key)) "(any string)"))
+      (when (and untranslated
+                 (stringp (aref untranslated (1- (length untranslated)))))
+        (aset untranslated (1- (length untranslated))
+              "(any string)"))
+      ;; Need to do this before erasing *Help* buffer in case event
+      ;; is a mouse click in an existing *Help* buffer.
+      (when up-event
+        (setq ev-type (event-basic-type up-event))
+        (let ((sequence (vector up-event)))
+          (when (and (eq ev-type 'mouse-1)
+                     mouse-1-click-follows-link
+                     (not (eq mouse-1-click-follows-link 'double))
+                     (setq mouse-1-remapped
+                           (mouse-on-link-p (event-start up-event))))
+            (setq mouse-1-tricky (and (integerp mouse-1-click-follows-link)
+                                      (> mouse-1-click-follows-link 0)))
+            (cond ((stringp mouse-1-remapped)
+                   (setq sequence mouse-1-remapped))
+                  ((vectorp mouse-1-remapped)
+                   (setcar up-event (elt mouse-1-remapped 0)))
+                  (t (setcar up-event 'mouse-2))))
+          (setq defn-up (key-binding sequence nil nil (event-start up-event)))
+          (when mouse-1-tricky
+            (setq sequence (vector up-event))
+            (aset sequence 0 'mouse-1)
+            (setq defn-up-tricky (key-binding sequence nil nil (event-start up-event))))))
+      (with-output-to-temp-buffer (help-buffer)
+        (princ (help-key-description key untranslated))
+        (princ (format "\
+%s runs the command %S
+  which is "
+                       mouse-msg defn))
+        (describe-function-1 defn)
+        (when up-event
+          (unless (or (null defn-up)
+                      (integerp defn-up)
+                      (equal defn-up 'undefined))
+            (princ (format "
+
+----------------- up-event %s----------------
+
+<%S>%s%s runs the command %S
+  which is "
+                           (if mouse-1-tricky "(short click) " "")
+                           ev-type mouse-msg
+                           (if mouse-1-remapped
+                               " is remapped to <mouse-2>\nwhich" "")
+                           defn-up))
+            (describe-function-1 defn-up))
+          (unless (or (null defn-up-tricky)
+                      (integerp defn-up-tricky)
+                      (eq defn-up-tricky 'undefined))
+            (princ (format "
+
+----------------- up-event (long click) ----------------
+
+Pressing <%S>%s for longer than %d milli-seconds
+runs the command %S
+  which is "
+                           ev-type mouse-msg
                            mouse-1-click-follows-link
-                           (not (eq mouse-1-click-follows-link 'double))
-                           (setq mouse-1-remapped
-                                 (with-current-buffer (window-buffer window)
-                                   (mouse-on-link-p (posn-point
-                                                     (event-start up-event))))))
-                  (setq mouse-1-tricky (and (integerp mouse-1-click-follows-link)
-                                            (> mouse-1-click-follows-link 0)))
-                  (cond ((stringp mouse-1-remapped)
-                         (setq sequence mouse-1-remapped))
-                        ((vectorp mouse-1-remapped)
-                         (setcar up-event (elt mouse-1-remapped 0)))
-                        (t (setcar up-event 'mouse-2))))
-                (setq defn (or (string-key-binding sequence)
-                               (key-binding sequence)))
-                (unless (or (null defn) (integerp defn) (equal defn 'undefined))
-                  (princ (if mouse-1-tricky
-                             "\n\n----------------- up-event (short click) ----------------\n\n"
-                           hdr))
-                  (setq hdr nil)
-                  (princ (symbol-name type))
-                  (if (windowp window)
-                      (princ " at that spot"))
-                  (if mouse-1-remapped
-                      (princ " is remapped to <mouse-2>\n  which" ))
-                  (princ " runs the command ")
-                  (prin1 defn)
-                  (princ "\n   which is ")
-                  (describe-function-1 defn))
-                (when mouse-1-tricky
-                  (setcar up-event 'mouse-1)
-                  (setq defn (or (string-key-binding (vector up-event))
-                                 (key-binding (vector up-event))))
-                  (unless (or (null defn) (integerp defn) (eq defn 'undefined))
-                    (princ (or hdr
-                               "\n\n----------------- up-event (long click) ----------------\n\n"))
-                    (princ "Pressing mouse-1")
-                    (if (windowp window)
-                        (princ " at that spot"))
-                    (princ (format " for longer than %d milli-seconds\n"
-                                   mouse-1-click-follows-link))
-                    (princ " runs the command ")
-                    (prin1 defn)
-                    (princ "\n   which is ")
-                    (describe-function-1 defn)))))
-            (print-help-return-message)))))))
+                           defn-up-tricky))
+            (describe-function-1 defn-up-tricky)))
+        (print-help-return-message)))))
 
 (defun describe-mode (&optional buffer)
   "Display documentation of current major mode and minor modes.
@@ -786,7 +764,7 @@ descriptions of the minor modes, each on a separate page.
 For this to work correctly for a minor mode, the mode's indicator
 variable \(listed in `minor-mode-alist') must also be a function
 whose documentation describes the minor mode."
-  (interactive)
+  (interactive "@")
   (unless buffer (setq buffer (current-buffer)))
   (help-setup-xref (list #'describe-mode buffer)
                    (interactive-p))