From ecb7cb34ceda6d6704ae08885ef63709dd1c99ba Mon Sep 17 00:00:00 2001
From: Karl Heuer <kwzh@gnu.org>
Date: Fri, 9 Jun 1995 00:55:30 +0000
Subject: [PATCH] (Vhelp_event_list): New var. (syms_of_keyboard): Set up Lisp
 var. (help_char_p): New function. (read_char, echo_char, read_key_sequence):
 Use help_char_p.

---
 src/keyboard.c | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/src/keyboard.c b/src/keyboard.c
index 78fcb6743ce..04ee068d454 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -148,6 +148,9 @@ int immediate_quit;
 /* Character to recognize as the help char.  */
 Lisp_Object Vhelp_char;
 
+/* List of other event types to recognize as meaning "help".  */
+Lisp_Object Vhelp_event_list;
+
 /* Form to execute when help char is typed.  */
 Lisp_Object Vhelp_form;
 
@@ -563,7 +566,7 @@ echo_char (c)
 	}
 
       if (current_kboard->echoptr == current_kboard->echobuf
-	  && EQ (c, Vhelp_char))
+	  && help_char_p (c))
 	{
 	  strcpy (ptr, " (Type ? for further options)");
 	  ptr += strlen (ptr);
@@ -2050,7 +2053,7 @@ read_char (commandflag, nmaps, maps, prev_event, used_mouse_menu)
   num_input_chars++;
 
   /* Process the help character specially if enabled */
-  if (EQ (c, Vhelp_char) && !NILP (Vhelp_form))
+  if (!NILP (Vhelp_form) && help_char_p (c))
     {
       Lisp_Object tem0;
       count = specpdl_ptr - specpdl;
@@ -2082,6 +2085,22 @@ read_char (commandflag, nmaps, maps, prev_event, used_mouse_menu)
   return c;
 }
 
+/* Return 1 if should recognize C as "the help character".  */
+
+int
+help_char_p (c)
+     Lisp_Object c;
+{
+  Lisp_Object tail;
+
+  if (EQ (c, Vhelp_char))
+    return 1;
+  for (tail = Vhelp_event_list; CONSP (tail); tail = XCONS (tail)->cdr)
+    if (EQ (c, XCONS (tail)->car))
+      return 1;
+  return 0;
+}
+
 /* Record the input event C in various ways.  */
 
 static void
@@ -5444,7 +5463,7 @@ read_key_sequence (keybuf, bufsize, prompt, dont_downcase_last,
 	  Lisp_Object head;
 
 	  head = EVENT_HEAD (key);
-	  if (EQ (head, Vhelp_char))
+	  if (help_char_p (head))
 	    {
 	      read_key_sequence_cmd = Vprefix_help_command;
 	      keybuf[t++] = key;
@@ -6965,6 +6984,11 @@ When it is read, do `(eval help-form)', and display result if it's a string.\n\
 If the value of `help-form' is nil, this char can be read normally.");
   XSETINT (Vhelp_char, Ctl ('H'));
 
+  DEFVAR_LISP ("help-event-list", &Vhelp_event_list,
+    "List of input events to recognize as meaning Help.\n\
+These work just like the value of `help-char' (see that).");
+  Vhelp_event_list = Qnil;
+
   DEFVAR_LISP ("help-form", &Vhelp_form,
     "Form to execute when character `help-char' is read.\n\
 If the form returns a string, that string is displayed.\n\
-- 
2.39.2