bug#355: M-x should prompt with function under cursor as default

[John Paul Wallington]

jidanni@jidanni.org writes:

> So I put the cursor upon the word customize-apropos-options and typed M-x,
> and would you believe I had to help emacs figure out what I wanted to do,
> which was of course to type M-x customize-apropos-options.
> (Yes, with the assistance of TAB.)
>
> Compare C-h f (describe-function) with the cursor in that position. It
> knows what to do: prompt with what it finds under the cursor.

Hm.  That's an interesting idea.

> P.S., I cannot help with patches because I am too busy reporting bugs
> I encounter in the surface interface, which I am much better at doing
> than coding. Each person has things they are better at doing.

Well, a patch follows.  If you could test it, I would be interested to
see whether you liked it in regular use.  I'll test it for a while too.

--- keyboard.c.~1.959.~ 2008-06-02 22:07:24.000000000 +0100
+++ keyboard.c  2008-06-05 02:04:13.000000000 +0100
@@ -10451,6 +10451,7 @@
      Lisp_Object prefixarg;
 {
   Lisp_Object function;
+  Lisp_Object symatpt;
   char buf[40];
   int saved_last_point_position;
   Lisp_Object saved_keys, saved_last_point_position_buffer;
@@ -10491,9 +10492,16 @@
      restricting to the set of all defined commands.  Don't provide
      any initial input.  Save the command read on the extended-command
      history list. */
+
+  symatpt = call0 (intern ("function-called-at-point"));
+  symatpt = (NILP (call1 (Qcommandp, symatpt))) ? Qnil : symatpt;
+  
+  if (!NILP (symatpt))
+    symatpt = SYMBOL_NAME (symatpt);
+      
   function = Fcompleting_read (build_string (buf),
                               Vobarray, Qcommandp,
-                              Qt, Qnil, Qextended_command_history, Qnil,
+                              Qt, symatpt, Qextended_command_history, Qnil,
                               Qnil);
 
 #ifdef HAVE_WINDOW_SYSTEM