Re: Incorrect advice how to restore previous window

[Kim F. Storm]

Richard Stallman <address@hidden> writes:

>     IMO it is rather obscure that we have a hook (several in fact) which
>     are run _after_ displaying a buffer in a window -- but no hook which
>     is run before the change.
>
> Do you mean window-configuration-change-hook?
> I guess there is no harm in having another similar hook
> at the beginning of Fset_window_buffer.

That is exactly what I suggested.

*** window.c    11 Feb 2007 21:37:29 +0100      1.573
--- window.c    20 Feb 2007 17:11:57 +0100      
***************
*** 201,207 ****
  
  static int window_initialized;
  
! /* Hook to run when window config changes.  */
  
  Lisp_Object Qwindow_configuration_change_hook;
  Lisp_Object Vwindow_configuration_change_hook;
--- 201,213 ----
  
  static int window_initialized;
  
! 
! /* Hook to run before setting window buffer.  */
! 
! Lisp_Object Qchange_window_buffer_functions;
! Lisp_Object Vchange_window_buffer_functions;
! 
! /* Hook to run after window config changes.  */
  
  Lisp_Object Qwindow_configuration_change_hook;
  Lisp_Object Vwindow_configuration_change_hook;
***************
*** 3275,3280 ****
--- 3281,3293 ----
    struct buffer *b = XBUFFER (buffer);
    int count = SPECPDL_INDEX ();
  
+   if (run_hooks_p
+       && BUFFERP (w->buffer)
+       && ! NILP (Vrun_hooks)
+       && ! NILP (Vchange_window_buffer_functions))
+     run_hook_with_args_2 (Qchange_window_buffer_functions,
+                         window, buffer);
+ 
    w->buffer = buffer;
  
    if (EQ (window, selected_window))
***************
*** 7289,7294 ****
--- 7302,7311 ----
    Qtemp_buffer_show_hook = intern ("temp-buffer-show-hook");
    staticpro (&Qtemp_buffer_show_hook);
  
+   Qchange_window_buffer_functions
+     = intern ("change-window-buffer-functions");
+   staticpro (&Qchange_window_buffer_functions);
+ 
    staticpro (&Vwindow_list);
  
    minibuf_selected_window = Qnil;
***************
*** 7489,7494 ****
--- 7506,7518 ----
  The selected frame is the one whose configuration has changed.  */);
    Vwindow_configuration_change_hook = Qnil;
  
+   DEFVAR_LISP ("change-window-buffer-functions",
+              &Vchange_window_buffer_functions,
+     doc: /* List of functions to call before changing buffer in window.
+ Each function is called with two arguments, the existing window and
+ its new buffer.  */);
+   Vchange_window_buffer_functions = Qnil;
+ 
    defsubr (&Sselected_window);
    defsubr (&Sminibuffer_window);
    defsubr (&Swindow_minibuffer_p);

-- 
Kim F. Storm <address@hidden> http://www.cua.dk