Include widget.h.

[bpt/emacs.git] / src / xmenu.c

/* X Communication module for terminals which understand the X protocol.
   Copyright (C) 1986, 88, 93, 94, 96, 99, 2000, 2001
   Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* X pop-up deck-of-cards menu facility for gnuemacs.
 *
 * Written by Jon Arnold and Roman Budzianowski
 * Mods and rewrite by Robert Krawitz
 *
 */

/* Modified by Fred Pierresteguy on December 93
   to make the popup menus and menubar use the Xt.  */

/* Rewritten for clarity and GC protection by rms in Feb 94.  */

#include <config.h>

/* On 4.3 this loses if it comes after xterm.h.  */
#include <signal.h>

#include <stdio.h>
#include "lisp.h"
#include "termhooks.h"
#include "keyboard.h"
#include "frame.h"
#include "window.h"
#include "blockinput.h"
#include "buffer.h"
#include "widget.h"

#ifdef MSDOS
#include "msdos.h"
#endif

#ifdef HAVE_X_WINDOWS
/* This may include sys/types.h, and that somehow loses
   if this is not done before the other system files.  */
#include "xterm.h"
#endif

/* Load sys/types.h if not already loaded.
   In some systems loading it twice is suicidal.  */
#ifndef makedev
#include <sys/types.h>
#endif

#include "dispextern.h"

#ifdef HAVE_X_WINDOWS
#undef HAVE_MULTILINGUAL_MENU
#ifdef USE_X_TOOLKIT
#include <X11/Xlib.h>
#include <X11/IntrinsicP.h>
#include <X11/CoreP.h>
#include <X11/StringDefs.h>
#include <X11/Shell.h>
#ifdef USE_LUCID
#include <X11/Xaw/Paned.h>
#endif /* USE_LUCID */
#include "../lwlib/lwlib.h"
#else /* not USE_X_TOOLKIT */
#include "../oldXMenu/XMenu.h"
#endif /* not USE_X_TOOLKIT */
#endif /* HAVE_X_WINDOWS */

#define min(x,y) (((x) < (y)) ? (x) : (y))
#define max(x,y) (((x) > (y)) ? (x) : (y))

#ifndef TRUE
#define TRUE 1
#define FALSE 0
#endif /* no TRUE */

Lisp_Object Vmenu_updating_frame;

Lisp_Object Qdebug_on_next_call;

extern Lisp_Object Qmenu_bar;
extern Lisp_Object Qmouse_click, Qevent_kind;

extern Lisp_Object QCtoggle, QCradio;

extern Lisp_Object Voverriding_local_map;
extern Lisp_Object Voverriding_local_map_menu_flag;

extern Lisp_Object Qoverriding_local_map, Qoverriding_terminal_local_map;

extern Lisp_Object Qmenu_bar_update_hook;

#ifdef USE_X_TOOLKIT
extern void set_frame_menubar ();
extern void process_expose_from_menu ();
extern XtAppContext Xt_app_con;

static Lisp_Object xdialog_show ();
void popup_get_selection ();
#endif

#ifdef USE_X_TOOLKIT

/* Define HAVE_BOXES if meus can handle radio and toggle buttons.  */

#define HAVE_BOXES 1
#endif

static void push_menu_item P_ ((Lisp_Object, Lisp_Object, Lisp_Object,
                                Lisp_Object, Lisp_Object, Lisp_Object,
                                Lisp_Object, Lisp_Object));
static int update_frame_menubar P_ ((struct frame *));
static Lisp_Object xmenu_show P_ ((struct frame *, int, int, int, int,
                                   Lisp_Object, char **));
static void keymap_panes P_ ((Lisp_Object *, int, int));
static void single_keymap_panes P_ ((Lisp_Object, Lisp_Object, Lisp_Object,
                                     int, int));
static void single_menu_item P_ ((Lisp_Object, Lisp_Object, Lisp_Object *,
                                  int, int, int *));
static void list_of_panes P_ ((Lisp_Object));
static void list_of_items P_ ((Lisp_Object));
\f
/* This holds a Lisp vector that holds the results of decoding
   the keymaps or alist-of-alists that specify a menu.

   It describes the panes and items within the panes.

   Each pane is described by 3 elements in the vector:
   t, the pane name, the pane's prefix key.
   Then follow the pane's items, with 5 elements per item:
   the item string, the enable flag, the item's value,
   the definition, and the equivalent keyboard key's description string.

   In some cases, multiple levels of menus may be described.
   A single vector slot containing nil indicates the start of a submenu.
   A single vector slot containing lambda indicates the end of a submenu.
   The submenu follows a menu item which is the way to reach the submenu.

   A single vector slot containing quote indicates that the
   following items should appear on the right of a dialog box.

   Using a Lisp vector to hold this information while we decode it
   takes care of protecting all the data from GC.  */

#define MENU_ITEMS_PANE_NAME 1
#define MENU_ITEMS_PANE_PREFIX 2
#define MENU_ITEMS_PANE_LENGTH 3

enum menu_item_idx
{
  MENU_ITEMS_ITEM_NAME = 0,
  MENU_ITEMS_ITEM_ENABLE,
  MENU_ITEMS_ITEM_VALUE,
  MENU_ITEMS_ITEM_EQUIV_KEY,
  MENU_ITEMS_ITEM_DEFINITION,
  MENU_ITEMS_ITEM_TYPE,
  MENU_ITEMS_ITEM_SELECTED,
  MENU_ITEMS_ITEM_HELP,
  MENU_ITEMS_ITEM_LENGTH
};

static Lisp_Object menu_items;

/* Number of slots currently allocated in menu_items.  */
static int menu_items_allocated;

/* This is the index in menu_items of the first empty slot.  */
static int menu_items_used;

/* The number of panes currently recorded in menu_items,
   excluding those within submenus.  */
static int menu_items_n_panes;

/* Current depth within submenus.  */
static int menu_items_submenu_depth;

/* Flag which when set indicates a dialog or menu has been posted by
   Xt on behalf of one of the widget sets.  */
int popup_activated_flag;

static int next_menubar_widget_id;

/* This is set nonzero after the user activates the menu bar, and set
   to zero again after the menu bars are redisplayed by prepare_menu_bar.
   While it is nonzero, all calls to set_frame_menubar go deep.

   I don't understand why this is needed, but it does seem to be
   needed on Motif, according to Marcus Daniels <marcus@sysc.pdx.edu>.  */

int pending_menu_activation;
\f
#ifdef USE_X_TOOLKIT

/* Return the frame whose ->output_data.x->id equals ID, or 0 if none.  */

static struct frame *
menubar_id_to_frame (id)
     LWLIB_ID id;
{
  Lisp_Object tail, frame;
  FRAME_PTR f;

  for (tail = Vframe_list; GC_CONSP (tail); tail = XCDR (tail))
    {
      frame = XCAR (tail);
      if (!GC_FRAMEP (frame))
        continue;
      f = XFRAME (frame);
      if (!FRAME_WINDOW_P (f))
        continue;
      if (f->output_data.x->id == id)
        return f;
    }
  return 0;
}

#endif
\f
/* Initialize the menu_items structure if we haven't already done so.
   Also mark it as currently empty.  */

static void
init_menu_items ()
{
  if (NILP (menu_items))
    {
      menu_items_allocated = 60;
      menu_items = Fmake_vector (make_number (menu_items_allocated), Qnil);
    }

  menu_items_used = 0;
  menu_items_n_panes = 0;
  menu_items_submenu_depth = 0;
}

/* Call at the end of generating the data in menu_items.
   This fills in the number of items in the last pane.  */

static void
finish_menu_items ()
{
}

/* Call when finished using the data for the current menu
   in menu_items.  */

static void
discard_menu_items ()
{
  /* Free the structure if it is especially large.
     Otherwise, hold on to it, to save time.  */
  if (menu_items_allocated > 200)
    {
      menu_items = Qnil;
      menu_items_allocated = 0;
    }
}

/* Make the menu_items vector twice as large.  */

static void
grow_menu_items ()
{
  Lisp_Object old;
  int old_size = menu_items_allocated;
  old = menu_items;

  menu_items_allocated *= 2;
  menu_items = Fmake_vector (make_number (menu_items_allocated), Qnil);
  bcopy (XVECTOR (old)->contents, XVECTOR (menu_items)->contents,
         old_size * sizeof (Lisp_Object));
}

/* Begin a submenu.  */

static void
push_submenu_start ()
{
  if (menu_items_used + 1 > menu_items_allocated)
    grow_menu_items ();

  XVECTOR (menu_items)->contents[menu_items_used++] = Qnil;
  menu_items_submenu_depth++;
}

/* End a submenu.  */

static void
push_submenu_end ()
{
  if (menu_items_used + 1 > menu_items_allocated)
    grow_menu_items ();

  XVECTOR (menu_items)->contents[menu_items_used++] = Qlambda;
  menu_items_submenu_depth--;
}

/* Indicate boundary between left and right.  */

static void
push_left_right_boundary ()
{
  if (menu_items_used + 1 > menu_items_allocated)
    grow_menu_items ();

  XVECTOR (menu_items)->contents[menu_items_used++] = Qquote;
}

/* Start a new menu pane in menu_items..
   NAME is the pane name.  PREFIX_VEC is a prefix key for this pane.  */

static void
push_menu_pane (name, prefix_vec)
     Lisp_Object name, prefix_vec;
{
  if (menu_items_used + MENU_ITEMS_PANE_LENGTH > menu_items_allocated)
    grow_menu_items ();

  if (menu_items_submenu_depth == 0)
    menu_items_n_panes++;
  XVECTOR (menu_items)->contents[menu_items_used++] = Qt;
  XVECTOR (menu_items)->contents[menu_items_used++] = name;
  XVECTOR (menu_items)->contents[menu_items_used++] = prefix_vec;
}

/* Push one menu item into the current pane.  NAME is the string to
   display.  ENABLE if non-nil means this item can be selected.  KEY
   is the key generated by choosing this item, or nil if this item
   doesn't really have a definition.  DEF is the definition of this
   item.  EQUIV is the textual description of the keyboard equivalent
   for this item (or nil if none).  TYPE is the type of this menu
   item, one of nil, `toggle' or `radio'. */

static void
push_menu_item (name, enable, key, def, equiv, type, selected, help)
     Lisp_Object name, enable, key, def, equiv, type, selected, help;
{
  if (menu_items_used + MENU_ITEMS_ITEM_LENGTH > menu_items_allocated)
    grow_menu_items ();

  XVECTOR (menu_items)->contents[menu_items_used++] = name;
  XVECTOR (menu_items)->contents[menu_items_used++] = enable;
  XVECTOR (menu_items)->contents[menu_items_used++] = key;
  XVECTOR (menu_items)->contents[menu_items_used++] = equiv;
  XVECTOR (menu_items)->contents[menu_items_used++] = def;
  XVECTOR (menu_items)->contents[menu_items_used++] = type;
  XVECTOR (menu_items)->contents[menu_items_used++] = selected;
  XVECTOR (menu_items)->contents[menu_items_used++] = help;
}
\f
/* Look through KEYMAPS, a vector of keymaps that is NMAPS long,
   and generate menu panes for them in menu_items.
   If NOTREAL is nonzero,
   don't bother really computing whether an item is enabled.  */

static void
keymap_panes (keymaps, nmaps, notreal)
     Lisp_Object *keymaps;
     int nmaps;
     int notreal;
{
  int mapno;

  init_menu_items ();

  /* Loop over the given keymaps, making a pane for each map.
     But don't make a pane that is empty--ignore that map instead.
     P is the number of panes we have made so far.  */
  for (mapno = 0; mapno < nmaps; mapno++)
    single_keymap_panes (keymaps[mapno],
                         map_prompt (keymaps[mapno]), Qnil, notreal, 10);

  finish_menu_items ();
}

/* This is a recursive subroutine of keymap_panes.
   It handles one keymap, KEYMAP.
   The other arguments are passed along
   or point to local variables of the previous function.
   If NOTREAL is nonzero, only check for equivalent key bindings, don't
   evaluate expressions in menu items and don't make any menu.

   If we encounter submenus deeper than MAXDEPTH levels, ignore them.  */

static void
single_keymap_panes (keymap, pane_name, prefix, notreal, maxdepth)
     Lisp_Object keymap;
     Lisp_Object pane_name;
     Lisp_Object prefix;
     int notreal;
     int maxdepth;
{
  Lisp_Object pending_maps = Qnil;
  Lisp_Object tail, item;
  struct gcpro gcpro1, gcpro2;
  int notbuttons = 0;

  if (maxdepth <= 0)
    return;

  push_menu_pane (pane_name, prefix);

#ifndef HAVE_BOXES
  /* Remember index for first item in this pane so we can go back and
     add a prefix when (if) we see the first button.  After that, notbuttons
     is set to 0, to mark that we have seen a button and all non button
     items need a prefix.  */
  notbuttons = menu_items_used;
#endif

  for (tail = keymap; CONSP (tail); tail = XCDR (tail))
    {
      GCPRO2 (keymap, pending_maps);
      /* Look at each key binding, and if it is a menu item add it
         to this menu.  */
      item = XCAR (tail);
      if (CONSP (item))
        single_menu_item (XCAR (item), XCDR (item),
                          &pending_maps, notreal, maxdepth, &notbuttons);
      else if (VECTORP (item))
        {
          /* Loop over the char values represented in the vector.  */
          int len = XVECTOR (item)->size;
          int c;
          for (c = 0; c < len; c++)
            {
              Lisp_Object character;
              XSETFASTINT (character, c);
              single_menu_item (character, XVECTOR (item)->contents[c],
                                &pending_maps, notreal, maxdepth, &notbuttons);
            }
        }
      UNGCPRO;
    }

  /* Process now any submenus which want to be panes at this level.  */
  while (!NILP (pending_maps))
    {
      Lisp_Object elt, eltcdr, string;
      elt = Fcar (pending_maps);
      eltcdr = XCDR (elt);
      string = XCAR (eltcdr);
      /* We no longer discard the @ from the beginning of the string here.
         Instead, we do this in xmenu_show.  */
      single_keymap_panes (Fcar (elt), string,
                           XCDR (eltcdr), notreal, maxdepth - 1);
      pending_maps = Fcdr (pending_maps);
    }
}
\f
/* This is a subroutine of single_keymap_panes that handles one
   keymap entry.
   KEY is a key in a keymap and ITEM is its binding. 
   PENDING_MAPS_PTR points to a list of keymaps waiting to be made into
   separate panes.
   If NOTREAL is nonzero, only check for equivalent key bindings, don't
   evaluate expressions in menu items and don't make any menu.
   If we encounter submenus deeper than MAXDEPTH levels, ignore them.
   NOTBUTTONS_PTR is only used when simulating toggle boxes and radio
   buttons.  It points to variable notbuttons in single_keymap_panes,
   which keeps track of if we have seen a button in this menu or not.  */

static void
single_menu_item (key, item, pending_maps_ptr, notreal, maxdepth,
                  notbuttons_ptr)
     Lisp_Object key, item;
     Lisp_Object *pending_maps_ptr;
     int maxdepth, notreal;
     int *notbuttons_ptr;
{
  Lisp_Object map, item_string, enabled;
  struct gcpro gcpro1, gcpro2;
  int res;
  
  /* Parse the menu item and leave the result in item_properties.  */
  GCPRO2 (key, item);
  res = parse_menu_item (item, notreal, 0);
  UNGCPRO;
  if (!res)
    return;                     /* Not a menu item.  */

  map = XVECTOR (item_properties)->contents[ITEM_PROPERTY_MAP];
  
  if (notreal)
    {
      /* We don't want to make a menu, just traverse the keymaps to
         precompute equivalent key bindings.  */
      if (!NILP (map))
        single_keymap_panes (map, Qnil, key, 1, maxdepth - 1);
      return;
    }

  enabled = XVECTOR (item_properties)->contents[ITEM_PROPERTY_ENABLE];
  item_string = XVECTOR (item_properties)->contents[ITEM_PROPERTY_NAME]; 

  if (!NILP (map) && XSTRING (item_string)->data[0] == '@')
    {
      if (!NILP (enabled))
        /* An enabled separate pane. Remember this to handle it later.  */
        *pending_maps_ptr = Fcons (Fcons (map, Fcons (item_string, key)),
                                   *pending_maps_ptr);
      return;
    }

#ifndef HAVE_BOXES
  /* Simulate radio buttons and toggle boxes by putting a prefix in
     front of them.  */
  {
    Lisp_Object prefix = Qnil;
    Lisp_Object type = XVECTOR (item_properties)->contents[ITEM_PROPERTY_TYPE];
    if (!NILP (type))
      {
        Lisp_Object selected
          = XVECTOR (item_properties)->contents[ITEM_PROPERTY_SELECTED];

        if (*notbuttons_ptr)
          /* The first button. Line up previous items in this menu.  */
          {
            int index = *notbuttons_ptr; /* Index for first item this menu.  */
            int submenu = 0;
            Lisp_Object tem;
            while (index < menu_items_used)
              {
                tem
                  = XVECTOR (menu_items)->contents[index + MENU_ITEMS_ITEM_NAME];
                if (NILP (tem))
                  {
                    index++;
                    submenu++;          /* Skip sub menu.  */
                  }
                else if (EQ (tem, Qlambda))
                  {
                    index++;
                    submenu--;          /* End sub menu.  */
                  }
                else if (EQ (tem, Qt))
                  index += 3;           /* Skip new pane marker. */
                else if (EQ (tem, Qquote))
                  index++;              /* Skip a left, right divider. */
                else
                  {
                    if (!submenu && XSTRING (tem)->data[0] != '\0'
                        && XSTRING (tem)->data[0] != '-')
                      XVECTOR (menu_items)->contents[index + MENU_ITEMS_ITEM_NAME]
                        = concat2 (build_string ("    "), tem);
                    index += MENU_ITEMS_ITEM_LENGTH;
                  }
              }
            *notbuttons_ptr = 0;
          }

        /* Calculate prefix, if any, for this item.  */
        if (EQ (type, QCtoggle))
          prefix = build_string (NILP (selected) ? "[ ] " : "[X] ");
        else if (EQ (type, QCradio))
          prefix = build_string (NILP (selected) ? "( ) " : "(*) ");
      }
    /* Not a button. If we have earlier buttons, then we need a prefix.  */
    else if (!*notbuttons_ptr && XSTRING (item_string)->data[0] != '\0'
             && XSTRING (item_string)->data[0] != '-')
      prefix = build_string ("    ");

    if (!NILP (prefix))
      item_string = concat2 (prefix, item_string);
  }
#endif /* not HAVE_BOXES */
 
#ifndef USE_X_TOOLKIT
  if (!NILP(map))
    /* Indicate visually that this is a submenu.  */
    item_string = concat2 (item_string, build_string (" >"));
#endif

  push_menu_item (item_string, enabled, key,
                  XVECTOR (item_properties)->contents[ITEM_PROPERTY_DEF],
                  XVECTOR (item_properties)->contents[ITEM_PROPERTY_KEYEQ],
                  XVECTOR (item_properties)->contents[ITEM_PROPERTY_TYPE],
                  XVECTOR (item_properties)->contents[ITEM_PROPERTY_SELECTED],
                  XVECTOR (item_properties)->contents[ITEM_PROPERTY_HELP]);

#ifdef USE_X_TOOLKIT
  /* Display a submenu using the toolkit.  */
  if (! (NILP (map) || NILP (enabled)))
    {
      push_submenu_start ();
      single_keymap_panes (map, Qnil, key, 0, maxdepth - 1);
      push_submenu_end ();
    }
#endif
}
\f
/* Push all the panes and items of a menu described by the
   alist-of-alists MENU.
   This handles old-fashioned calls to x-popup-menu.  */

static void
list_of_panes (menu)
     Lisp_Object menu;
{
  Lisp_Object tail;

  init_menu_items ();

  for (tail = menu; !NILP (tail); tail = Fcdr (tail))
    {
      Lisp_Object elt, pane_name, pane_data;
      elt = Fcar (tail);
      pane_name = Fcar (elt);
      CHECK_STRING (pane_name, 0);
      push_menu_pane (pane_name, Qnil);
      pane_data = Fcdr (elt);
      CHECK_CONS (pane_data, 0);
      list_of_items (pane_data);
    }

  finish_menu_items ();
}

/* Push the items in a single pane defined by the alist PANE.  */

static void
list_of_items (pane)
     Lisp_Object pane;
{
  Lisp_Object tail, item, item1;

  for (tail = pane; !NILP (tail); tail = Fcdr (tail))
    {
      item = Fcar (tail);
      if (STRINGP (item))
        push_menu_item (item, Qnil, Qnil, Qt, Qnil, Qnil, Qnil, Qnil);
      else if (NILP (item))
        push_left_right_boundary ();
      else
        {
          CHECK_CONS (item, 0);
          item1 = Fcar (item);
          CHECK_STRING (item1, 1);
          push_menu_item (item1, Qt, Fcdr (item), Qt, Qnil, Qnil, Qnil, Qnil);
        }
    }
}
\f
DEFUN ("x-popup-menu", Fx_popup_menu, Sx_popup_menu, 2, 2, 0,
  "Pop up a deck-of-cards menu and return user's selection.\n\
POSITION is a position specification.  This is either a mouse button event\n\
or a list ((XOFFSET YOFFSET) WINDOW)\n\
where XOFFSET and YOFFSET are positions in pixels from the top left\n\
corner of WINDOW's frame.  (WINDOW may be a frame object instead of a window.)\n\
This controls the position of the center of the first line\n\
in the first pane of the menu, not the top left of the menu as a whole.\n\
If POSITION is t, it means to use the current mouse position.\n\
\n\
MENU is a specifier for a menu.  For the simplest case, MENU is a keymap.\n\
The menu items come from key bindings that have a menu string as well as\n\
a definition; actually, the \"definition\" in such a key binding looks like\n\
\(STRING . REAL-DEFINITION).  To give the menu a title, put a string into\n\
the keymap as a top-level element.\n\n\
If REAL-DEFINITION is nil, that puts a nonselectable string in the menu.\n\
Otherwise, REAL-DEFINITION should be a valid key binding definition.\n\
\n\
You can also use a list of keymaps as MENU.\n\
  Then each keymap makes a separate pane.\n\
When MENU is a keymap or a list of keymaps, the return value\n\
is a list of events.\n\n\
\n\
Alternatively, you can specify a menu of multiple panes\n\
  with a list of the form (TITLE PANE1 PANE2...),\n\
where each pane is a list of form (TITLE ITEM1 ITEM2...).\n\
Each ITEM is normally a cons cell (STRING . VALUE);\n\
but a string can appear as an item--that makes a nonselectable line\n\
in the menu.\n\
With this form of menu, the return value is VALUE from the chosen item.\n\
\n\
If POSITION is nil, don't display the menu at all, just precalculate the\n\
cached information about equivalent key sequences.")
  (position, menu)
     Lisp_Object position, menu;
{
  Lisp_Object keymap, tem;
  int xpos = 0, ypos = 0;
  Lisp_Object title;
  char *error_name;
  Lisp_Object selection;
  struct frame *f = NULL;
  Lisp_Object x, y, window;
  int keymaps = 0;
  int for_click = 0;
  struct gcpro gcpro1;

#ifdef HAVE_MENUS
  if (! NILP (position))
    {
      check_x ();

      /* Decode the first argument: find the window and the coordinates.  */
      if (EQ (position, Qt)
          || (CONSP (position) && (EQ (XCAR (position), Qmenu_bar)
                                   || EQ (XCAR (position), Qtool_bar))))
        {
          /* Use the mouse's current position.  */
          FRAME_PTR new_f = SELECTED_FRAME ();
          Lisp_Object bar_window;
          enum scroll_bar_part part;
          unsigned long time;

          if (mouse_position_hook)
            (*mouse_position_hook) (&new_f, 1, &bar_window,
                                    &part, &x, &y, &time);
          if (new_f != 0)
            XSETFRAME (window, new_f);
          else
            {
              window = selected_window;
              XSETFASTINT (x, 0);
              XSETFASTINT (y, 0);
            }
        }
      else
        {
          tem = Fcar (position);
          if (CONSP (tem))
            {
              window = Fcar (Fcdr (position));
              x = Fcar (tem);
              y = Fcar (Fcdr (tem));
            }
          else
            {
              for_click = 1;
              tem = Fcar (Fcdr (position));  /* EVENT_START (position) */
              window = Fcar (tem);           /* POSN_WINDOW (tem) */
              tem = Fcar (Fcdr (Fcdr (tem))); /* POSN_WINDOW_POSN (tem) */
              x = Fcar (tem);
              y = Fcdr (tem);
            }
        }

      CHECK_NUMBER (x, 0);
      CHECK_NUMBER (y, 0);

      /* Decode where to put the menu.  */

      if (FRAMEP (window))
        {
          f = XFRAME (window);
          xpos = 0;
          ypos = 0;
        }
      else if (WINDOWP (window))
        {
          CHECK_LIVE_WINDOW (window, 0);
          f = XFRAME (WINDOW_FRAME (XWINDOW (window)));

          xpos = (FONT_WIDTH (f->output_data.x->font)
                  * XFASTINT (XWINDOW (window)->left));
          ypos = (f->output_data.x->line_height
                  * XFASTINT (XWINDOW (window)->top));
        }
      else
        /* ??? Not really clean; should be CHECK_WINDOW_OR_FRAME,
           but I don't want to make one now.  */
        CHECK_WINDOW (window, 0);

      xpos += XINT (x);
      ypos += XINT (y);

      XSETFRAME (Vmenu_updating_frame, f);
    }
  Vmenu_updating_frame = Qnil;
#endif /* HAVE_MENUS */

  title = Qnil;
  GCPRO1 (title);

  /* Decode the menu items from what was specified.  */

  keymap = get_keymap (menu, 0, 0);
  if (CONSP (keymap))
    {
      /* We were given a keymap.  Extract menu info from the keymap.  */
      Lisp_Object prompt;

      /* Extract the detailed info to make one pane.  */
      keymap_panes (&menu, 1, NILP (position));

      /* Search for a string appearing directly as an element of the keymap.
         That string is the title of the menu.  */
      prompt = map_prompt (keymap);
      if (NILP (title) && !NILP (prompt))
        title = prompt;

      /* Make that be the pane title of the first pane.  */
      if (!NILP (prompt) && menu_items_n_panes >= 0)
        XVECTOR (menu_items)->contents[MENU_ITEMS_PANE_NAME] = prompt;

      keymaps = 1;
    }
  else if (CONSP (menu) && KEYMAPP (XCAR (menu)))
    {
      /* We were given a list of keymaps.  */
      int nmaps = XFASTINT (Flength (menu));
      Lisp_Object *maps
        = (Lisp_Object *) alloca (nmaps * sizeof (Lisp_Object));
      int i;

      title = Qnil;

      /* The first keymap that has a prompt string
         supplies the menu title.  */
      for (tem = menu, i = 0; CONSP (tem); tem = Fcdr (tem))
        {
          Lisp_Object prompt;

          maps[i++] = keymap = get_keymap (Fcar (tem), 1, 0);

          prompt = map_prompt (keymap);
          if (NILP (title) && !NILP (prompt))
            title = prompt;
        }

      /* Extract the detailed info to make one pane.  */
      keymap_panes (maps, nmaps, NILP (position));

      /* Make the title be the pane title of the first pane.  */
      if (!NILP (title) && menu_items_n_panes >= 0)
        XVECTOR (menu_items)->contents[MENU_ITEMS_PANE_NAME] = title;

      keymaps = 1;
    }
  else
    {
      /* We were given an old-fashioned menu.  */
      title = Fcar (menu);
      CHECK_STRING (title, 1);

      list_of_panes (Fcdr (menu));

      keymaps = 0;
    }
  
  if (NILP (position))
    {
      discard_menu_items ();
      UNGCPRO;
      return Qnil;
    }

#ifdef HAVE_MENUS
  /* Display them in a menu.  */
  BLOCK_INPUT;

  selection = xmenu_show (f, xpos, ypos, for_click,
                          keymaps, title, &error_name);
  UNBLOCK_INPUT;

  discard_menu_items ();

  UNGCPRO;
#endif /* HAVE_MENUS */

  if (error_name) error (error_name);
  return selection;
}

#ifdef HAVE_MENUS

DEFUN ("x-popup-dialog", Fx_popup_dialog, Sx_popup_dialog, 2, 2, 0,
  "Pop up a dialog box and return user's selection.\n\
POSITION specifies which frame to use.\n\
This is normally a mouse button event or a window or frame.\n\
If POSITION is t, it means to use the frame the mouse is on.\n\
The dialog box appears in the middle of the specified frame.\n\
\n\
CONTENTS specifies the alternatives to display in the dialog box.\n\
It is a list of the form (TITLE ITEM1 ITEM2...).\n\
Each ITEM is a cons cell (STRING . VALUE).\n\
The return value is VALUE from the chosen item.\n\n\
An ITEM may also be just a string--that makes a nonselectable item.\n\
An ITEM may also be nil--that means to put all preceding items\n\
on the left of the dialog box and all following items on the right.\n\
\(By default, approximately half appear on each side.)")
  (position, contents)
     Lisp_Object position, contents;
{
  struct frame * f = NULL;
  Lisp_Object window;

  check_x ();

  /* Decode the first argument: find the window or frame to use.  */
  if (EQ (position, Qt)
      || (CONSP (position) && (EQ (XCAR (position), Qmenu_bar)
                               || EQ (XCAR (position), Qtool_bar))))
    {
#if 0 /* Using the frame the mouse is on may not be right.  */
      /* Use the mouse's current position.  */
      FRAME_PTR new_f = SELECTED_FRAME ();
      Lisp_Object bar_window;
      int part;
      unsigned long time;
      Lisp_Object x, y;

      (*mouse_position_hook) (&new_f, 1, &bar_window, &part, &x, &y, &time);

      if (new_f != 0)
        XSETFRAME (window, new_f);
      else
        window = selected_window;
#endif
      window = selected_window;
    }
  else if (CONSP (position))
    {
      Lisp_Object tem;
      tem = Fcar (position);
      if (CONSP (tem))
        window = Fcar (Fcdr (position));
      else
        {
          tem = Fcar (Fcdr (position));  /* EVENT_START (position) */
          window = Fcar (tem);       /* POSN_WINDOW (tem) */
        }
    }
  else if (WINDOWP (position) || FRAMEP (position))
    window = position;
  else
    window = Qnil;

  /* Decode where to put the menu.  */

  if (FRAMEP (window))
    f = XFRAME (window);
  else if (WINDOWP (window))
    {
      CHECK_LIVE_WINDOW (window, 0);
      f = XFRAME (WINDOW_FRAME (XWINDOW (window)));
    }
  else
    /* ??? Not really clean; should be CHECK_WINDOW_OR_FRAME,
       but I don't want to make one now.  */
    CHECK_WINDOW (window, 0);

#ifndef USE_X_TOOLKIT
  /* Display a menu with these alternatives
     in the middle of frame F.  */
  {
    Lisp_Object x, y, frame, newpos;
    XSETFRAME (frame, f);
    XSETINT (x, x_pixel_width (f) / 2);
    XSETINT (y, x_pixel_height (f) / 2);
    newpos = Fcons (Fcons (x, Fcons (y, Qnil)), Fcons (frame, Qnil));

    return Fx_popup_menu (newpos,
                          Fcons (Fcar (contents), Fcons (contents, Qnil)));
  }
#else
  {
    Lisp_Object title;
    char *error_name;
    Lisp_Object selection;

    /* Decode the dialog items from what was specified.  */
    title = Fcar (contents);
    CHECK_STRING (title, 1);

    list_of_panes (Fcons (contents, Qnil));

    /* Display them in a dialog box.  */
    BLOCK_INPUT;
    selection = xdialog_show (f, 0, title, &error_name);
    UNBLOCK_INPUT;

    discard_menu_items ();

    if (error_name) error (error_name);
    return selection;
  }
#endif
}
\f
#ifdef USE_X_TOOLKIT

/* Loop in Xt until the menu pulldown or dialog popup has been
   popped down (deactivated).  This is used for x-popup-menu
   and x-popup-dialog; it is not used for the menu bar any more.

   NOTE: All calls to popup_get_selection should be protected
   with BLOCK_INPUT, UNBLOCK_INPUT wrappers.  */

void
popup_get_selection (initial_event, dpyinfo, id)
     XEvent *initial_event;
     struct x_display_info *dpyinfo;
     LWLIB_ID id;
{
  XEvent event;

  /* Define a queue to save up for later unreading
     all X events that don't pertain to the menu.  */
  struct event_queue
    {
      XEvent event;
      struct event_queue *next;
    };
  
  struct event_queue *queue = NULL;
  struct event_queue *queue_tmp;

  if (initial_event)
    event = *initial_event;
  else
    XtAppNextEvent (Xt_app_con, &event);

  while (1)
    {
      /* Handle expose events for editor frames right away.  */
      if (event.type == Expose)
        process_expose_from_menu (event);
      /* Make sure we don't consider buttons grabbed after menu goes.
         And make sure to deactivate for any ButtonRelease,
         even if XtDispatchEvent doesn't do that.  */
      else if (event.type == ButtonRelease
               && dpyinfo->display == event.xbutton.display)
        {
          dpyinfo->grabbed &= ~(1 << event.xbutton.button);
          popup_activated_flag = 0;
#ifdef USE_MOTIF /* Pretending that the event came from a 
                    Btn1Down seems the only way to convince Motif to
                    activate its callbacks; setting the XmNmenuPost
                    isn't working. --marcus@sysc.pdx.edu.  */
          event.xbutton.button = 1;
#endif
        }
      /* If the user presses a key, deactivate the menu.
         The user is likely to do that if we get wedged.  */
      else if (event.type == KeyPress
               && dpyinfo->display == event.xbutton.display)
        {
          KeySym keysym = XLookupKeysym (&event.xkey, 0);
          if (!IsModifierKey (keysym))
            {
              popup_activated_flag = 0;
              break;
            }
        }
      /* Button presses outside the menu also pop it down.  */
      else if (event.type == ButtonPress
               && event.xany.display == dpyinfo->display
               && x_any_window_to_frame (dpyinfo, event.xany.window))
        {
          popup_activated_flag = 0;
          break;
        }

      /* Queue all events not for this popup,
         except for Expose, which we've already handled, and ButtonRelease.
         Note that the X window is associated with the frame if this
         is a menu bar popup, but not if it's a dialog box.  So we use
         x_non_menubar_window_to_frame, not x_any_window_to_frame.  */
      if (event.type != Expose
          && !(event.type == ButtonRelease
               && dpyinfo->display == event.xbutton.display)
          && (event.xany.display != dpyinfo->display
              || x_non_menubar_window_to_frame (dpyinfo, event.xany.window)))
        {
          queue_tmp = (struct event_queue *) xmalloc (sizeof *queue_tmp);
          queue_tmp->event = event;
          queue_tmp->next = queue;
          queue = queue_tmp;
        }
      else
        XtDispatchEvent (&event);

      if (!popup_activated ())
        break;
      XtAppNextEvent (Xt_app_con, &event);
    }

  /* Unread any events that we got but did not handle.  */
  while (queue != NULL) 
    {
      queue_tmp = queue;
      XPutBackEvent (queue_tmp->event.xany.display, &queue_tmp->event);
      queue = queue_tmp->next;
      xfree ((char *)queue_tmp);
      /* Cause these events to get read as soon as we UNBLOCK_INPUT.  */
      interrupt_input_pending = 1;
    }
}

/* Activate the menu bar of frame F.
   This is called from keyboard.c when it gets the
   menu_bar_activate_event out of the Emacs event queue.

   To activate the menu bar, we use the X button-press event
   that was saved in saved_menu_event.
   That makes the toolkit do its thing.

   But first we recompute the menu bar contents (the whole tree).

   The reason for saving the button event until here, instead of
   passing it to the toolkit right away, is that we can safely
   execute Lisp code.  */
   
void
x_activate_menubar (f)
     FRAME_PTR f;
{
  if (!f->output_data.x->saved_menu_event->type)
    return;

  set_frame_menubar (f, 0, 1);
  BLOCK_INPUT;
  XtDispatchEvent ((XEvent *) f->output_data.x->saved_menu_event);
  UNBLOCK_INPUT;
#ifdef USE_MOTIF
  if (f->output_data.x->saved_menu_event->type == ButtonRelease)
    pending_menu_activation = 1;
#endif
  
  /* Ignore this if we get it a second time.  */
  f->output_data.x->saved_menu_event->type = 0;
}

/* Detect if a dialog or menu has been posted.  */

int
popup_activated ()
{
  return popup_activated_flag;
}

/* This callback is invoked when the user selects a menubar cascade
   pushbutton, but before the pulldown menu is posted.  */

static void
popup_activate_callback (widget, id, client_data)
     Widget widget;
     LWLIB_ID id;
     XtPointer client_data;
{
  popup_activated_flag = 1;
}

/* This callback is invoked when a dialog or menu is finished being
   used and has been unposted.  */

static void
popup_deactivate_callback (widget, id, client_data)
     Widget widget;
     LWLIB_ID id;
     XtPointer client_data;
{
  popup_activated_flag = 0;
}

/* Lwlib callback called when menu items are highlighted/unhighlighted
   while moving the mouse over them.  WIDGET is the menu bar or menu
   popup widget.  ID is its LWLIB_ID.  CALL_DATA contains a pointer to
   the widget_value structure for the menu item, or null in case of
   unhighlighting.  */

void
menu_highlight_callback (widget, id, call_data)
     Widget widget;
     LWLIB_ID id;
     void *call_data;
{
  widget_value *wv = (widget_value *) call_data;
  struct frame *f;
  Lisp_Object frame, help;

  help = wv && wv->help ? build_string (wv->help) : Qnil;
  
  /* Determine the frame for the help event.  */
  f = menubar_id_to_frame (id);
  if (f)
    {
      XSETFRAME (frame, f);
      kbd_buffer_store_help_event (frame, help);
    }
  else
    {
      /* WIDGET is the popup menu.  It's parent is the frame's 
         widget.  See which frame that is.  */
      Widget frame_widget = XtParent (widget);
      Lisp_Object tail;

      for (tail = Vframe_list; GC_CONSP (tail); tail = XCDR (tail))
        {
          frame = XCAR (tail);
          if (GC_FRAMEP (frame)
              && (f = XFRAME (frame),
                  FRAME_X_P (f) && f->output_data.x->widget == frame_widget))
            break;
        }

      show_help_echo (help, Qnil, Qnil, Qnil, 1);
    }
}

/* This callback is called from the menu bar pulldown menu
   when the user makes a selection.
   Figure out what the user chose
   and put the appropriate events into the keyboard buffer.  */

static void
menubar_selection_callback (widget, id, client_data)
     Widget widget;
     LWLIB_ID id;
     XtPointer client_data;
{
  Lisp_Object prefix, entry;
  FRAME_PTR f = menubar_id_to_frame (id);
  Lisp_Object vector;
  Lisp_Object *subprefix_stack;
  int submenu_depth = 0;
  int i;

  if (!f)
    return;
  entry = Qnil;
  subprefix_stack = (Lisp_Object *) alloca (f->menu_bar_items_used * sizeof (Lisp_Object));
  vector = f->menu_bar_vector;
  prefix = Qnil;
  i = 0;
  while (i < f->menu_bar_items_used)
    {
      if (EQ (XVECTOR (vector)->contents[i], Qnil))
        {
          subprefix_stack[submenu_depth++] = prefix;
          prefix = entry;
          i++;
        }
      else if (EQ (XVECTOR (vector)->contents[i], Qlambda))
        {
          prefix = subprefix_stack[--submenu_depth];
          i++;
        }
      else if (EQ (XVECTOR (vector)->contents[i], Qt))
        {
          prefix = XVECTOR (vector)->contents[i + MENU_ITEMS_PANE_PREFIX];
          i += MENU_ITEMS_PANE_LENGTH;
        }
      else
        {
          entry = XVECTOR (vector)->contents[i + MENU_ITEMS_ITEM_VALUE];
          /* The EMACS_INT cast avoids a warning.  There's no problem
             as long as pointers have enough bits to hold small integers.  */
          if ((int) (EMACS_INT) client_data == i)
            {
              int j;
              struct input_event buf;
              Lisp_Object frame;

              XSETFRAME (frame, f);
              buf.kind = MENU_BAR_EVENT;
              buf.frame_or_window = frame;
              buf.arg = frame;
              kbd_buffer_store_event (&buf);

              for (j = 0; j < submenu_depth; j++)
                if (!NILP (subprefix_stack[j]))
                  {
                    buf.kind = MENU_BAR_EVENT;
                    buf.frame_or_window = frame;
                    buf.arg = subprefix_stack[j];
                    kbd_buffer_store_event (&buf);
                  }

              if (!NILP (prefix))
                {
                  buf.kind = MENU_BAR_EVENT;
                  buf.frame_or_window = frame;
                  buf.arg = prefix;
                  kbd_buffer_store_event (&buf);
                }

              buf.kind = MENU_BAR_EVENT;
              buf.frame_or_window = frame;
              buf.arg = entry;
              kbd_buffer_store_event (&buf);

              return;
            }
          i += MENU_ITEMS_ITEM_LENGTH;
        }
    }
}

/* Allocate a widget_value, blocking input.  */

widget_value *
xmalloc_widget_value ()
{
  widget_value *value;

  BLOCK_INPUT;
  value = malloc_widget_value ();
  UNBLOCK_INPUT;

  return value;
}

/* This recursively calls free_widget_value on the tree of widgets.
   It must free all data that was malloc'ed for these widget_values.
   In Emacs, many slots are pointers into the data of Lisp_Strings, and
   must be left alone.  */

void
free_menubar_widget_value_tree (wv)
     widget_value *wv;
{
  if (! wv) return;

  wv->name = wv->value = wv->key = (char *) 0xDEADBEEF;

  if (wv->contents && (wv->contents != (widget_value*)1))
    {
      free_menubar_widget_value_tree (wv->contents);
      wv->contents = (widget_value *) 0xDEADBEEF;
    }
  if (wv->next)
    {
      free_menubar_widget_value_tree (wv->next);
      wv->next = (widget_value *) 0xDEADBEEF;
    }
  BLOCK_INPUT;
  free_widget_value (wv);
  UNBLOCK_INPUT;
}
\f
/* Return a tree of widget_value structures for a menu bar item
   whose event type is ITEM_KEY (with string ITEM_NAME)
   and whose contents come from the list of keymaps MAPS.  */

static widget_value *
single_submenu (item_key, item_name, maps)
     Lisp_Object item_key, item_name, maps;
{
  widget_value *wv, *prev_wv, *save_wv, *first_wv;
  int i;
  int submenu_depth = 0;
  Lisp_Object length;
  int len;
  Lisp_Object *mapvec;
  widget_value **submenu_stack;
  int previous_items = menu_items_used;
  int top_level_items = 0;

  length = Flength (maps);
  len = XINT (length);

  /* Convert the list MAPS into a vector MAPVEC.  */
  mapvec = (Lisp_Object *) alloca (len * sizeof (Lisp_Object));
  for (i = 0; i < len; i++)
    {
      mapvec[i] = Fcar (maps);
      maps = Fcdr (maps);
    }

  menu_items_n_panes = 0;

  /* Loop over the given keymaps, making a pane for each map.
     But don't make a pane that is empty--ignore that map instead.  */
  for (i = 0; i < len; i++)
    {
      if (SYMBOLP (mapvec[i])
          || (CONSP (mapvec[i]) && !KEYMAPP (mapvec[i])))
        {
          /* Here we have a command at top level in the menu bar
             as opposed to a submenu.  */
          top_level_items = 1;
          push_menu_pane (Qnil, Qnil);
          push_menu_item (item_name, Qt, item_key, mapvec[i],
                          Qnil, Qnil, Qnil, Qnil);
        }
      else
        single_keymap_panes (mapvec[i], item_name, item_key, 0, 10);
    }

  /* Create a tree of widget_value objects
     representing the panes and their items.  */

  submenu_stack
    = (widget_value **) alloca (menu_items_used * sizeof (widget_value *));
  wv = xmalloc_widget_value ();
  wv->name = "menu";
  wv->value = 0;
  wv->enabled = 1;
  wv->button_type = BUTTON_TYPE_NONE;
  first_wv = wv;
  save_wv = 0;
  prev_wv = 0;
 
  /* Loop over all panes and items made during this call
     and construct a tree of widget_value objects.
     Ignore the panes and items made by previous calls to
     single_submenu, even though those are also in menu_items.  */
  i = previous_items;
  while (i < menu_items_used)
    {
      if (EQ (XVECTOR (menu_items)->contents[i], Qnil))
        {
          submenu_stack[submenu_depth++] = save_wv;
          save_wv = prev_wv;
          prev_wv = 0;
          i++;
        }
      else if (EQ (XVECTOR (menu_items)->contents[i], Qlambda))
        {
          prev_wv = save_wv;
          save_wv = submenu_stack[--submenu_depth];
          i++;
        }
      else if (EQ (XVECTOR (menu_items)->contents[i], Qt)
               && submenu_depth != 0)
        i += MENU_ITEMS_PANE_LENGTH;
      /* Ignore a nil in the item list.
         It's meaningful only for dialog boxes.  */
      else if (EQ (XVECTOR (menu_items)->contents[i], Qquote))
        i += 1;
      else if (EQ (XVECTOR (menu_items)->contents[i], Qt))
        {
          /* Create a new pane.  */
          Lisp_Object pane_name, prefix;
          char *pane_string;
          pane_name = XVECTOR (menu_items)->contents[i + MENU_ITEMS_PANE_NAME];
          prefix = XVECTOR (menu_items)->contents[i + MENU_ITEMS_PANE_PREFIX];
#ifndef HAVE_MULTILINGUAL_MENU
          if (STRINGP (pane_name) && STRING_MULTIBYTE (pane_name))
            pane_name = string_make_unibyte (pane_name);
#endif
          pane_string = (NILP (pane_name)
                         ? "" : (char *) XSTRING (pane_name)->data);
          /* If there is just one top-level pane, put all its items directly
             under the top-level menu.  */
          if (menu_items_n_panes == 1)
            pane_string = "";

          /* If the pane has a meaningful name,
             make the pane a top-level menu item
             with its items as a submenu beneath it.  */
          if (strcmp (pane_string, ""))
            {
              wv = xmalloc_widget_value ();
              if (save_wv)
                save_wv->next = wv;
              else
                first_wv->contents = wv;
              wv->name = pane_string;
              /* Ignore the @ that means "separate pane".
                 This is a kludge, but this isn't worth more time.  */
              if (!NILP (prefix) && wv->name[0] == '@')
                wv->name++;
              wv->value = 0;
              wv->enabled = 1;
              wv->button_type = BUTTON_TYPE_NONE;
            }
          save_wv = wv;
          prev_wv = 0;
          i += MENU_ITEMS_PANE_LENGTH;
        }
      else
        {
          /* Create a new item within current pane.  */
          Lisp_Object item_name, enable, descrip, def, type, selected;
          Lisp_Object help;
          
          item_name = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_NAME];
          enable = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_ENABLE];
          descrip
            = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_EQUIV_KEY];
          def = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_DEFINITION];
          type = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_TYPE];
          selected = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_SELECTED];
          help = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_HELP];

#ifndef HAVE_MULTILINGUAL_MENU
          if (STRING_MULTIBYTE (item_name))
            item_name = string_make_unibyte (item_name);
          if (STRINGP (descrip) && STRING_MULTIBYTE (descrip))
            descrip = string_make_unibyte (descrip);
#endif

          wv = xmalloc_widget_value ();
          if (prev_wv) 
            prev_wv->next = wv;
          else
            save_wv->contents = wv;

          wv->name = (char *) XSTRING (item_name)->data;
          if (!NILP (descrip))
            wv->key = (char *) XSTRING (descrip)->data;
          wv->value = 0;
          /* The EMACS_INT cast avoids a warning.  There's no problem
             as long as pointers have enough bits to hold small integers.  */
          wv->call_data = (!NILP (def) ? (void *) (EMACS_INT) i : 0);
          wv->enabled = !NILP (enable);
          
          if (NILP (type))
            wv->button_type = BUTTON_TYPE_NONE;
          else if (EQ (type, QCradio))
            wv->button_type = BUTTON_TYPE_RADIO;
          else if (EQ (type, QCtoggle))
            wv->button_type = BUTTON_TYPE_TOGGLE;
          else
            abort ();

          wv->selected = !NILP (selected);
          if (STRINGP (help))
            wv->help = XSTRING (help)->data;
                   
          prev_wv = wv;

          i += MENU_ITEMS_ITEM_LENGTH;
        }
    }

  /* If we have just one "menu item"
     that was originally a button, return it by itself.  */
  if (top_level_items && first_wv->contents && first_wv->contents->next == 0)
    {
      wv = first_wv->contents;
      free_widget_value (first_wv);
      return wv;
    }

  return first_wv;
}


\f
/* Recompute all the widgets of frame F, when the menu bar has been
   changed.  Value is non-zero if widgets were updated.  */

static int
update_frame_menubar (f)
     FRAME_PTR f;
{
  struct x_output *x = f->output_data.x;
  int columns, rows;
  
  if (!x->menubar_widget || XtIsManaged (x->menubar_widget))
    return 0;

  BLOCK_INPUT;
  /* Save the size of the frame because the pane widget doesn't accept
     to resize itself. So force it.  */
  columns = f->width;
  rows = f->height;

  /* Do the voodoo which means "I'm changing lots of things, don't try
     to refigure sizes until I'm done."  */
  lw_refigure_widget (x->column_widget, False);

  /* The order in which children are managed is the top to bottom
     order in which they are displayed in the paned window.  First,
     remove the text-area widget.  */
  XtUnmanageChild (x->edit_widget);

  /* Remove the menubar that is there now, and put up the menubar that
     should be there.  */
  XtManageChild (x->menubar_widget);
  XtMapWidget (x->menubar_widget);
  XtVaSetValues (x->menubar_widget, XtNmappedWhenManaged, 1, NULL);

  /* Re-manage the text-area widget, and then thrash the sizes.  */
  XtManageChild (x->edit_widget);
  x_set_menu_resources_from_menu_face (f, x->menubar_widget);
  lw_refigure_widget (x->column_widget, True);

  /* Force the pane widget to resize itself with the right values.  */
  EmacsFrameSetCharSize (x->edit_widget, columns, rows);
  UNBLOCK_INPUT;
  return 1;
}

/* Set the contents of the menubar widgets of frame F.
   The argument FIRST_TIME is currently ignored;
   it is set the first time this is called, from initialize_frame_menubar.  */

void
set_frame_menubar (f, first_time, deep_p)
     FRAME_PTR f;
     int first_time;
     int deep_p;
{
  Widget menubar_widget = f->output_data.x->menubar_widget;
  Lisp_Object items;
  widget_value *wv, *first_wv, *prev_wv = 0;
  int i;
  LWLIB_ID id;

  XSETFRAME (Vmenu_updating_frame, f);

  if (f->output_data.x->id == 0)
    f->output_data.x->id = next_menubar_widget_id++;
  id = f->output_data.x->id;

  if (! menubar_widget)
    deep_p = 1;
  else if (pending_menu_activation && !deep_p)
    deep_p = 1;
  /* Make the first call for any given frame always go deep.  */
  else if (!f->output_data.x->saved_menu_event && !deep_p)
    {
      deep_p = 1;
      f->output_data.x->saved_menu_event = (XEvent*)xmalloc (sizeof (XEvent));
      f->output_data.x->saved_menu_event->type = 0;
    }

  wv = xmalloc_widget_value ();
  wv->name = "menubar";
  wv->value = 0;
  wv->enabled = 1;
  wv->button_type = BUTTON_TYPE_NONE;
  first_wv = wv;

  if (deep_p)
    {
      /* Make a widget-value tree representing the entire menu trees.  */

      struct buffer *prev = current_buffer;
      Lisp_Object buffer;
      int specpdl_count = specpdl_ptr - specpdl;
      int previous_menu_items_used = f->menu_bar_items_used;
      Lisp_Object *previous_items
        = (Lisp_Object *) alloca (previous_menu_items_used
                                  * sizeof (Lisp_Object));

      /* If we are making a new widget, its contents are empty,
         do always reinitialize them.  */
      if (! menubar_widget)
        previous_menu_items_used = 0;

      buffer = XWINDOW (FRAME_SELECTED_WINDOW (f))->buffer;
      specbind (Qinhibit_quit, Qt);
      /* Don't let the debugger step into this code
         because it is not reentrant.  */
      specbind (Qdebug_on_next_call, Qnil);

      record_unwind_protect (Fset_match_data, Fmatch_data (Qnil, Qnil));
      if (NILP (Voverriding_local_map_menu_flag))
        {
          specbind (Qoverriding_terminal_local_map, Qnil);
          specbind (Qoverriding_local_map, Qnil);
        }

      set_buffer_internal_1 (XBUFFER (buffer));

      /* Run the Lucid hook.  */
      safe_run_hooks (Qactivate_menubar_hook);
      
      /* If it has changed current-menubar from previous value,
         really recompute the menubar from the value.  */
      if (! NILP (Vlucid_menu_bar_dirty_flag))
        call0 (Qrecompute_lucid_menubar);
      safe_run_hooks (Qmenu_bar_update_hook);
      FRAME_MENU_BAR_ITEMS (f) = menu_bar_items (FRAME_MENU_BAR_ITEMS (f));

      items = FRAME_MENU_BAR_ITEMS (f);

      inhibit_garbage_collection ();

      /* Save the frame's previous menu bar contents data.  */
      bcopy (XVECTOR (f->menu_bar_vector)->contents, previous_items,
             previous_menu_items_used * sizeof (Lisp_Object));

      /* Fill in the current menu bar contents.  */
      menu_items = f->menu_bar_vector;
      menu_items_allocated = XVECTOR (menu_items)->size;
      init_menu_items ();
      for (i = 0; i < XVECTOR (items)->size; i += 4)
        {
          Lisp_Object key, string, maps;

          key = XVECTOR (items)->contents[i];
          string = XVECTOR (items)->contents[i + 1];
          maps = XVECTOR (items)->contents[i + 2];
          if (NILP (string))
            break;

          wv = single_submenu (key, string, maps);
          if (prev_wv) 
            prev_wv->next = wv;
          else
            first_wv->contents = wv;
          /* Don't set wv->name here; GC during the loop might relocate it.  */
          wv->enabled = 1;
          wv->button_type = BUTTON_TYPE_NONE;
          prev_wv = wv;
        }

      finish_menu_items ();

      set_buffer_internal_1 (prev);
      unbind_to (specpdl_count, Qnil);

      /* If there has been no change in the Lisp-level contents
         of the menu bar, skip redisplaying it.  Just exit.  */

      for (i = 0; i < previous_menu_items_used; i++)
        if (menu_items_used == i
            || (!EQ (previous_items[i], XVECTOR (menu_items)->contents[i])))
          break;
      if (i == menu_items_used && i == previous_menu_items_used && i != 0)
        {
          free_menubar_widget_value_tree (first_wv);
          menu_items = Qnil;

          return;
        }

      /* Now GC cannot happen during the lifetime of the widget_value,
         so it's safe to store data from a Lisp_String.  */
      wv = first_wv->contents;
      for (i = 0; i < XVECTOR (items)->size; i += 4)
        {
          Lisp_Object string;
          string = XVECTOR (items)->contents[i + 1];
          if (NILP (string))
            break;
          wv->name = (char *) XSTRING (string)->data;
          wv = wv->next;
        }

      f->menu_bar_vector = menu_items;
      f->menu_bar_items_used = menu_items_used;
      menu_items = Qnil;
    }
  else
    {
      /* Make a widget-value tree containing
         just the top level menu bar strings.  */

      items = FRAME_MENU_BAR_ITEMS (f);
      for (i = 0; i < XVECTOR (items)->size; i += 4)
        {
          Lisp_Object string;

          string = XVECTOR (items)->contents[i + 1];
          if (NILP (string))
            break;

          wv = xmalloc_widget_value ();
          wv->name = (char *) XSTRING (string)->data;
          wv->value = 0;
          wv->enabled = 1;
          wv->button_type = BUTTON_TYPE_NONE;
          /* This prevents lwlib from assuming this
             menu item is really supposed to be empty.  */
          /* The EMACS_INT cast avoids a warning.
             This value just has to be different from small integers.  */
          wv->call_data = (void *) (EMACS_INT) (-1);

          if (prev_wv) 
            prev_wv->next = wv;
          else
            first_wv->contents = wv;
          prev_wv = wv;
        }

      /* Forget what we thought we knew about what is in the
         detailed contents of the menu bar menus.
         Changing the top level always destroys the contents.  */
      f->menu_bar_items_used = 0;
    }

  /* Create or update the menu bar widget.  */

  BLOCK_INPUT;

  if (menubar_widget)
    {
      /* Disable resizing (done for Motif!) */
      lw_allow_resizing (f->output_data.x->widget, False);

      /* The third arg is DEEP_P, which says to consider the entire
         menu trees we supply, rather than just the menu bar item names.  */
      lw_modify_all_widgets (id, first_wv, deep_p);

      /* Re-enable the edit widget to resize.  */
      lw_allow_resizing (f->output_data.x->widget, True);
    }
  else
    {
      menubar_widget = lw_create_widget ("menubar", "menubar", id, first_wv, 
                                         f->output_data.x->column_widget,
                                         0,
                                         popup_activate_callback,
                                         menubar_selection_callback,
                                         popup_deactivate_callback,
                                         menu_highlight_callback);
      f->output_data.x->menubar_widget = menubar_widget;
    }

  {
    int menubar_size 
      = (f->output_data.x->menubar_widget
         ? (f->output_data.x->menubar_widget->core.height
            + f->output_data.x->menubar_widget->core.border_width)
         : 0);

#if 0 /* Experimentally, we now get the right results
         for -geometry -0-0 without this.  24 Aug 96, rms.  */
#ifdef USE_LUCID
    if (FRAME_EXTERNAL_MENU_BAR (f))
      {
        Dimension ibw = 0;
        XtVaGetValues (f->output_data.x->column_widget,
                       XtNinternalBorderWidth, &ibw, NULL);
        menubar_size += ibw;
      }
#endif /* USE_LUCID */
#endif /* 0 */

    f->output_data.x->menubar_height = menubar_size;
  }
  
  free_menubar_widget_value_tree (first_wv);
  if (!update_frame_menubar (f))
    x_set_menu_resources_from_menu_face (f, menubar_widget);

  UNBLOCK_INPUT;
}

/* Called from Fx_create_frame to create the initial menubar of a frame
   before it is mapped, so that the window is mapped with the menubar already
   there instead of us tacking it on later and thrashing the window after it
   is visible.  */

void
initialize_frame_menubar (f)
     FRAME_PTR f;
{
  /* This function is called before the first chance to redisplay
     the frame.  It has to be, so the frame will have the right size.  */
  FRAME_MENU_BAR_ITEMS (f) = menu_bar_items (FRAME_MENU_BAR_ITEMS (f));
  set_frame_menubar (f, 1, 1);
}

/* Get rid of the menu bar of frame F, and free its storage.
   This is used when deleting a frame, and when turning off the menu bar.  */

void
free_frame_menubar (f)
     FRAME_PTR f;
{
  Widget menubar_widget;

  menubar_widget = f->output_data.x->menubar_widget;

  f->output_data.x->menubar_height = 0;
  
  if (menubar_widget)
    {
      BLOCK_INPUT;
      lw_destroy_all_widgets ((LWLIB_ID) f->output_data.x->id);
      f->output_data.x->menubar_widget = NULL;
      UNBLOCK_INPUT;
    }
}

#endif /* USE_X_TOOLKIT */
\f
/* xmenu_show actually displays a menu using the panes and items in menu_items
   and returns the value selected from it.
   There are two versions of xmenu_show, one for Xt and one for Xlib.
   Both assume input is blocked by the caller.  */

/* F is the frame the menu is for.
   X and Y are the frame-relative specified position,
   relative to the inside upper left corner of the frame F.
   FOR_CLICK is nonzero if this menu was invoked for a mouse click.
   KEYMAPS is 1 if this menu was specified with keymaps;
    in that case, we return a list containing the chosen item's value
    and perhaps also the pane's prefix.
   TITLE is the specified menu title.
   ERROR is a place to store an error message string in case of failure.
   (We return nil on failure, but the value doesn't actually matter.)  */

#ifdef USE_X_TOOLKIT

/* We need a unique id for each widget handled by the Lucid Widget
   library.

   For the main windows, and popup menus, we use this counter,
   which we increment each time after use.  This starts from 1<<16.

   For menu bars, we use numbers starting at 0, counted in
   next_menubar_widget_id.  */
LWLIB_ID widget_id_tick;

static Lisp_Object *volatile menu_item_selection;

static void
popup_selection_callback (widget, id, client_data)
     Widget widget;
     LWLIB_ID id;
     XtPointer client_data;
{
  menu_item_selection = (Lisp_Object *) client_data;
}

static Lisp_Object
xmenu_show (f, x, y, for_click, keymaps, title, error)
     FRAME_PTR f;
     int x;
     int y;
     int for_click;
     int keymaps;
     Lisp_Object title;
     char **error;
{
  int i;
  LWLIB_ID menu_id;
  Widget menu;
  Arg av[2];
  int ac = 0;
  widget_value *wv, *save_wv = 0, *first_wv = 0, *prev_wv = 0;
  widget_value **submenu_stack
    = (widget_value **) alloca (menu_items_used * sizeof (widget_value *));
  Lisp_Object *subprefix_stack
    = (Lisp_Object *) alloca (menu_items_used * sizeof (Lisp_Object));
  int submenu_depth = 0;
  XButtonPressedEvent dummy;

  int first_pane;

  *error = NULL;

  if (menu_items_used <= MENU_ITEMS_PANE_LENGTH)
    {
      *error = "Empty menu";
      return Qnil;
    }

  /* Create a tree of widget_value objects
     representing the panes and their items.  */
  wv = xmalloc_widget_value ();
  wv->name = "menu";
  wv->value = 0;
  wv->enabled = 1;
  wv->button_type = BUTTON_TYPE_NONE;
  first_wv = wv;
  first_pane = 1;
 
  /* Loop over all panes and items, filling in the tree.  */
  i = 0;
  while (i < menu_items_used)
    {
      if (EQ (XVECTOR (menu_items)->contents[i], Qnil))
        {
          submenu_stack[submenu_depth++] = save_wv;
          save_wv = prev_wv;
          prev_wv = 0;
          first_pane = 1;
          i++;
        }
      else if (EQ (XVECTOR (menu_items)->contents[i], Qlambda))
        {
          prev_wv = save_wv;
          save_wv = submenu_stack[--submenu_depth];
          first_pane = 0;
          i++;
        }
      else if (EQ (XVECTOR (menu_items)->contents[i], Qt)
               && submenu_depth != 0)
        i += MENU_ITEMS_PANE_LENGTH;
      /* Ignore a nil in the item list.
         It's meaningful only for dialog boxes.  */
      else if (EQ (XVECTOR (menu_items)->contents[i], Qquote))
        i += 1;
      else if (EQ (XVECTOR (menu_items)->contents[i], Qt))
        {
          /* Create a new pane.  */
          Lisp_Object pane_name, prefix;
          char *pane_string;
          pane_name = XVECTOR (menu_items)->contents[i + MENU_ITEMS_PANE_NAME];
          prefix = XVECTOR (menu_items)->contents[i + MENU_ITEMS_PANE_PREFIX];
#ifndef HAVE_MULTILINGUAL_MENU
          if (!NILP (pane_name) && STRING_MULTIBYTE (pane_name))
            pane_name = string_make_unibyte (pane_name);
#endif
          pane_string = (NILP (pane_name)
                         ? "" : (char *) XSTRING (pane_name)->data);
          /* If there is just one top-level pane, put all its items directly
             under the top-level menu.  */
          if (menu_items_n_panes == 1)
            pane_string = "";

          /* If the pane has a meaningful name,
             make the pane a top-level menu item
             with its items as a submenu beneath it.  */
          if (!keymaps && strcmp (pane_string, ""))
            {
              wv = xmalloc_widget_value ();
              if (save_wv)
                save_wv->next = wv;
              else
                first_wv->contents = wv;
              wv->name = pane_string;
              if (keymaps && !NILP (prefix))
                wv->name++;
              wv->value = 0;
              wv->enabled = 1;
              wv->button_type = BUTTON_TYPE_NONE;
              save_wv = wv;
              prev_wv = 0;
            }
          else if (first_pane)
            {
              save_wv = wv;
              prev_wv = 0;
            }
          first_pane = 0;
          i += MENU_ITEMS_PANE_LENGTH;
        }
      else
        {
          /* Create a new item within current pane.  */
          Lisp_Object item_name, enable, descrip, def, type, selected, help;
          item_name = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_NAME];
          enable = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_ENABLE];
          descrip
            = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_EQUIV_KEY];
          def = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_DEFINITION];
          type = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_TYPE];
          selected = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_SELECTED];
          help = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_HELP];

#ifndef HAVE_MULTILINGUAL_MENU
          if (STRINGP (item_name) && STRING_MULTIBYTE (item_name))
            item_name = string_make_unibyte (item_name);
          if (STRINGP (descrip) && STRING_MULTIBYTE (descrip))
            item_name = string_make_unibyte (descrip);
#endif
 
          wv = xmalloc_widget_value ();
          if (prev_wv) 
            prev_wv->next = wv;
          else 
            save_wv->contents = wv;
          wv->name = (char *) XSTRING (item_name)->data;
          if (!NILP (descrip))
            wv->key = (char *) XSTRING (descrip)->data;
          wv->value = 0;
          /* If this item has a null value,
             make the call_data null so that it won't display a box
             when the mouse is on it.  */
          wv->call_data
            = (!NILP (def) ? (void *) &XVECTOR (menu_items)->contents[i] : 0);
          wv->enabled = !NILP (enable);

          if (NILP (type))
            wv->button_type = BUTTON_TYPE_NONE;
          else if (EQ (type, QCtoggle))
            wv->button_type = BUTTON_TYPE_TOGGLE;
          else if (EQ (type, QCradio))
            wv->button_type = BUTTON_TYPE_RADIO;
          else
            abort ();

          wv->selected = !NILP (selected);
          if (STRINGP (help))
            wv->help = XSTRING (help)->data;
          
          prev_wv = wv;

          i += MENU_ITEMS_ITEM_LENGTH;
        }
    }

  /* Deal with the title, if it is non-nil.  */
  if (!NILP (title))
    {
      widget_value *wv_title = xmalloc_widget_value ();
      widget_value *wv_sep1 = xmalloc_widget_value ();
      widget_value *wv_sep2 = xmalloc_widget_value ();

      wv_sep2->name = "--";
      wv_sep2->next = first_wv->contents;

      wv_sep1->name = "--";
      wv_sep1->next = wv_sep2;

#ifndef HAVE_MULTILINGUAL_MENU
      if (STRING_MULTIBYTE (title))
        title = string_make_unibyte (title);
#endif
      wv_title->name = (char *) XSTRING (title)->data;
      wv_title->enabled = True;
      wv_title->button_type = BUTTON_TYPE_NONE;
      wv_title->next = wv_sep1;
      first_wv->contents = wv_title;
    }

  /* Actually create the menu.  */
  menu_id = widget_id_tick++;
  menu = lw_create_widget ("popup", first_wv->name, menu_id, first_wv,
                           f->output_data.x->widget, 1, 0,
                           popup_selection_callback,
                           popup_deactivate_callback,
                           menu_highlight_callback);

  /* Adjust coordinates to relative to the outer (window manager) window.  */
  {
    Window child;
    int win_x = 0, win_y = 0;

    /* Find the position of the outside upper-left corner of
       the inner window, with respect to the outer window.  */
    if (f->output_data.x->parent_desc != FRAME_X_DISPLAY_INFO (f)->root_window)
      {
        BLOCK_INPUT;
        XTranslateCoordinates (FRAME_X_DISPLAY (f),

                               /* From-window, to-window.  */
                               f->output_data.x->window_desc,
                               f->output_data.x->parent_desc,

                               /* From-position, to-position.  */
                               0, 0, &win_x, &win_y,

                               /* Child of window.  */
                               &child);
        UNBLOCK_INPUT;
        x += win_x;
        y += win_y;
      }
  }

  /* Adjust coordinates to be root-window-relative.  */
  x += f->output_data.x->left_pos;
  y += f->output_data.x->top_pos;

  dummy.type = ButtonPress;
  dummy.serial = 0;
  dummy.send_event = 0;
  dummy.display = FRAME_X_DISPLAY (f);
  dummy.time = CurrentTime;
  dummy.root = FRAME_X_DISPLAY_INFO (f)->root_window;
  dummy.window = dummy.root;
  dummy.subwindow = dummy.root;
  dummy.x_root = x;
  dummy.y_root = y;
  dummy.x = x;
  dummy.y = y;
  dummy.state = (FRAME_X_DISPLAY_INFO (f)->grabbed >> 1) * Button1Mask;
  dummy.button = 0;
  for (i = 0; i < 5; i++)
    if (FRAME_X_DISPLAY_INFO (f)->grabbed & (1 << i))
      dummy.button = i;

  /* Don't allow any geometry request from the user.  */
  XtSetArg (av[ac], XtNgeometry, 0); ac++;
  XtSetValues (menu, av, ac);

  /* Free the widget_value objects we used to specify the contents.  */
  free_menubar_widget_value_tree (first_wv);

  /* Override any default settings with ones from the `menu' face.  */
  x_set_menu_resources_from_menu_face (f, menu);

  /* No selection has been chosen yet.  */
  menu_item_selection = 0;

  /* Display the menu.  */
  lw_popup_menu (menu, (XEvent *) &dummy);
  popup_activated_flag = 1;

  /* Process events that apply to the menu.  */
  popup_get_selection ((XEvent *) 0, FRAME_X_DISPLAY_INFO (f), menu_id);

  /* fp turned off the following statement and wrote a comment
     that it is unnecessary--that the menu has already disappeared.
     Nowadays the menu disappears ok, all right, but
     we need to delete the widgets or multiple ones will pile up.  */
  lw_destroy_all_widgets (menu_id); 

  /* Find the selected item, and its pane, to return
     the proper value.  */
  if (menu_item_selection != 0)
    {
      Lisp_Object prefix, entry;

      prefix = entry = Qnil;
      i = 0;
      while (i < menu_items_used)
        {
          if (EQ (XVECTOR (menu_items)->contents[i], Qnil))
            {
              subprefix_stack[submenu_depth++] = prefix;
              prefix = entry;
              i++;
            }
          else if (EQ (XVECTOR (menu_items)->contents[i], Qlambda))
            {
              prefix = subprefix_stack[--submenu_depth];
              i++;
            }
          else if (EQ (XVECTOR (menu_items)->contents[i], Qt))
            {
              prefix
                = XVECTOR (menu_items)->contents[i + MENU_ITEMS_PANE_PREFIX];
              i += MENU_ITEMS_PANE_LENGTH;
            }
          /* Ignore a nil in the item list.
             It's meaningful only for dialog boxes.  */
          else if (EQ (XVECTOR (menu_items)->contents[i], Qquote))
            i += 1;
          else
            {
              entry
                = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_VALUE];
              if (menu_item_selection == &XVECTOR (menu_items)->contents[i])
                {
                  if (keymaps != 0)
                    {
                      int j;

                      entry = Fcons (entry, Qnil);
                      if (!NILP (prefix))
                        entry = Fcons (prefix, entry);
                      for (j = submenu_depth - 1; j >= 0; j--)
                        if (!NILP (subprefix_stack[j]))
                          entry = Fcons (subprefix_stack[j], entry);
                    }
                  return entry;
                }
              i += MENU_ITEMS_ITEM_LENGTH;
            }
        }
    }

  return Qnil;
}
\f
static void
dialog_selection_callback (widget, id, client_data)
     Widget widget;
     LWLIB_ID id;
     XtPointer client_data;
{
  /* The EMACS_INT cast avoids a warning.  There's no problem
     as long as pointers have enough bits to hold small integers.  */
  if ((int) (EMACS_INT) client_data != -1)
    menu_item_selection = (Lisp_Object *) client_data;
  BLOCK_INPUT;
  lw_destroy_all_widgets (id);
  UNBLOCK_INPUT;
  popup_activated_flag = 0;
}

static char * button_names [] = {
  "button1", "button2", "button3", "button4", "button5",
  "button6", "button7", "button8", "button9", "button10" };

static Lisp_Object
xdialog_show (f, keymaps, title, error)
     FRAME_PTR f;
     int keymaps;
     Lisp_Object title;
     char **error;
{
  int i, nb_buttons=0;
  LWLIB_ID dialog_id;
  Widget menu;
  char dialog_name[6];

  widget_value *wv, *first_wv = 0, *prev_wv = 0;

  /* Number of elements seen so far, before boundary.  */
  int left_count = 0;
  /* 1 means we've seen the boundary between left-hand elts and right-hand.  */
  int boundary_seen = 0;

  *error = NULL;

  if (menu_items_n_panes > 1)
    {
      *error = "Multiple panes in dialog box";
      return Qnil;
    }

  /* Create a tree of widget_value objects
     representing the text label and buttons.  */
  {
    Lisp_Object pane_name, prefix;
    char *pane_string;
    pane_name = XVECTOR (menu_items)->contents[MENU_ITEMS_PANE_NAME];
    prefix = XVECTOR (menu_items)->contents[MENU_ITEMS_PANE_PREFIX];
    pane_string = (NILP (pane_name)
                   ? "" : (char *) XSTRING (pane_name)->data);  
    prev_wv = xmalloc_widget_value ();
    prev_wv->value = pane_string;
    if (keymaps && !NILP (prefix))
      prev_wv->name++;
    prev_wv->enabled = 1;
    prev_wv->name = "message";
    first_wv = prev_wv;
 
    /* Loop over all panes and items, filling in the tree.  */
    i = MENU_ITEMS_PANE_LENGTH;
    while (i < menu_items_used)
      {
        
        /* Create a new item within current pane.  */
        Lisp_Object item_name, enable, descrip;
        item_name = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_NAME];
        enable = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_ENABLE];
        descrip
          = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_EQUIV_KEY];
        
        if (NILP (item_name))
          {
            free_menubar_widget_value_tree (first_wv);
            *error = "Submenu in dialog items";
            return Qnil;
          }
        if (EQ (item_name, Qquote))
          {
            /* This is the boundary between left-side elts
               and right-side elts.  Stop incrementing right_count.  */
            boundary_seen = 1;
            i++;
            continue;
          }
        if (nb_buttons >= 9)
          {
            free_menubar_widget_value_tree (first_wv);
            *error = "Too many dialog items";
            return Qnil;
          }

        wv = xmalloc_widget_value ();
        prev_wv->next = wv;
        wv->name = (char *) button_names[nb_buttons];
        if (!NILP (descrip))
          wv->key = (char *) XSTRING (descrip)->data;
        wv->value = (char *) XSTRING (item_name)->data;
        wv->call_data = (void *) &XVECTOR (menu_items)->contents[i];
        wv->enabled = !NILP (enable);
        prev_wv = wv;

        if (! boundary_seen)
          left_count++;

        nb_buttons++;
        i += MENU_ITEMS_ITEM_LENGTH;
      }

    /* If the boundary was not specified,
       by default put half on the left and half on the right.  */
    if (! boundary_seen)
      left_count = nb_buttons - nb_buttons / 2;

    wv = xmalloc_widget_value ();
    wv->name = dialog_name;

    /* Dialog boxes use a really stupid name encoding
       which specifies how many buttons to use
       and how many buttons are on the right.
       The Q means something also.  */
    dialog_name[0] = 'Q';
    dialog_name[1] = '0' + nb_buttons;
    dialog_name[2] = 'B';
    dialog_name[3] = 'R';
    /* Number of buttons to put on the right.  */
    dialog_name[4] = '0' + nb_buttons - left_count;
    dialog_name[5] = 0;
    wv->contents = first_wv;
    first_wv = wv;
  }

  /* Actually create the dialog.  */
  dialog_id = widget_id_tick++;
  menu = lw_create_widget (first_wv->name, "dialog", dialog_id, first_wv,
                           f->output_data.x->widget, 1, 0,
                           dialog_selection_callback, 0, 0);
  lw_modify_all_widgets (dialog_id, first_wv->contents, True);
  /* Free the widget_value objects we used to specify the contents.  */
  free_menubar_widget_value_tree (first_wv);

  /* No selection has been chosen yet.  */
  menu_item_selection = 0;

  /* Display the menu.  */
  lw_pop_up_all_widgets (dialog_id);
  popup_activated_flag = 1;

  /* Process events that apply to the menu.  */
  popup_get_selection ((XEvent *) 0, FRAME_X_DISPLAY_INFO (f), dialog_id);

  lw_destroy_all_widgets (dialog_id); 

  /* Find the selected item, and its pane, to return
     the proper value.  */
  if (menu_item_selection != 0)
    {
      Lisp_Object prefix;

      prefix = Qnil;
      i = 0;
      while (i < menu_items_used)
        {
          Lisp_Object entry;

          if (EQ (XVECTOR (menu_items)->contents[i], Qt))
            {
              prefix
                = XVECTOR (menu_items)->contents[i + MENU_ITEMS_PANE_PREFIX];
              i += MENU_ITEMS_PANE_LENGTH;
            }
          else if (EQ (XVECTOR (menu_items)->contents[i], Qquote))
            {
              /* This is the boundary between left-side elts and
                 right-side elts.  */
              ++i;
            }
          else
            {
              entry
                = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_VALUE];
              if (menu_item_selection == &XVECTOR (menu_items)->contents[i])
                {
                  if (keymaps != 0)
                    {
                      entry = Fcons (entry, Qnil);
                      if (!NILP (prefix))
                        entry = Fcons (prefix, entry);
                    }
                  return entry;
                }
              i += MENU_ITEMS_ITEM_LENGTH;
            }
        }
    }

  return Qnil;
}

#else /* not USE_X_TOOLKIT */

/* The frame of the last activated non-toolkit menu bar.
   Used to generate menu help events.  */

static struct frame *menu_help_frame;


/* Show help HELP_STRING, or clear help if HELP_STRING is null.

   PANE is the pane number, and ITEM is the menu item number in
   the menu (currently not used).
   
   This cannot be done with generating a HELP_EVENT because
   XMenuActivate contains a loop that doesn't let Emacs process
   keyboard events.  */

static void
menu_help_callback (help_string, pane, item)
     char *help_string;
     int pane, item;
{
  extern Lisp_Object Qmenu_item;
  Lisp_Object *first_item;
  Lisp_Object pane_name;
  Lisp_Object menu_object;
 
  first_item = XVECTOR (menu_items)->contents;
  if (EQ (first_item[0], Qt))
    pane_name = first_item[MENU_ITEMS_PANE_NAME];
  else if (EQ (first_item[0], Qquote))
    /* This shouldn't happen, see xmenu_show.  */
    pane_name = build_string ("");
  else
    pane_name = first_item[MENU_ITEMS_ITEM_NAME];
 
  /* (menu-item MENU-NAME PANE-NUMBER)  */
  menu_object = Fcons (Qmenu_item,
                       Fcons (pane_name,
                              Fcons (make_number (pane), Qnil)));
  show_help_echo (help_string ? build_string (help_string) : Qnil,
                  Qnil, menu_object, make_number (item), 1);
}
  

static Lisp_Object
xmenu_show (f, x, y, for_click, keymaps, title, error)
     FRAME_PTR f;
     int x, y;
     int for_click;
     int keymaps;
     Lisp_Object title;
     char **error;
{
  Window root;          
  XMenu *menu;
  int pane, selidx, lpane, status;
  Lisp_Object entry, pane_prefix;
  char *datap;
  int ulx, uly, width, height;
  int dispwidth, dispheight;
  int i, j;
  int maxwidth;
  int dummy_int;
  unsigned int dummy_uint;

  *error = 0;
  if (menu_items_n_panes == 0)
    return Qnil;

  if (menu_items_used <= MENU_ITEMS_PANE_LENGTH)
    {
      *error = "Empty menu";
      return Qnil;
    }

  /* Figure out which root window F is on.  */
  XGetGeometry (FRAME_X_DISPLAY (f), FRAME_X_WINDOW (f), &root,
                &dummy_int, &dummy_int, &dummy_uint, &dummy_uint,
                &dummy_uint, &dummy_uint);

  /* Make the menu on that window.  */
  menu = XMenuCreate (FRAME_X_DISPLAY (f), root, "emacs");
  if (menu == NULL)
    {
      *error = "Can't create menu";
      return Qnil;
    }

#ifdef HAVE_X_WINDOWS
  /* Adjust coordinates to relative to the outer (window manager) window.  */
  {
    Window child;
    int win_x = 0, win_y = 0;

    /* Find the position of the outside upper-left corner of
       the inner window, with respect to the outer window.  */
    if (f->output_data.x->parent_desc != FRAME_X_DISPLAY_INFO (f)->root_window)
      {
        BLOCK_INPUT;
        XTranslateCoordinates (FRAME_X_DISPLAY (f),

                               /* From-window, to-window.  */
                               f->output_data.x->window_desc,
                               f->output_data.x->parent_desc,

                               /* From-position, to-position.  */
                               0, 0, &win_x, &win_y,

                               /* Child of window.  */
                               &child);
        UNBLOCK_INPUT;
        x += win_x;
        y += win_y;
      }
  }
#endif /* HAVE_X_WINDOWS */

  /* Adjust coordinates to be root-window-relative.  */
  x += f->output_data.x->left_pos;
  y += f->output_data.x->top_pos;
 
  /* Create all the necessary panes and their items.  */
  i = 0;
  while (i < menu_items_used)
    {
      if (EQ (XVECTOR (menu_items)->contents[i], Qt))
        {
          /* Create a new pane.  */
          Lisp_Object pane_name, prefix;
          char *pane_string;

          pane_name = XVECTOR (menu_items)->contents[i + MENU_ITEMS_PANE_NAME];
          prefix = XVECTOR (menu_items)->contents[i + MENU_ITEMS_PANE_PREFIX];
          pane_string = (NILP (pane_name)
                         ? "" : (char *) XSTRING (pane_name)->data);
          if (keymaps && !NILP (prefix))
            pane_string++;

          lpane = XMenuAddPane (FRAME_X_DISPLAY (f), menu, pane_string, TRUE);
          if (lpane == XM_FAILURE)
            {
              XMenuDestroy (FRAME_X_DISPLAY (f), menu);
              *error = "Can't create pane";
              return Qnil;
            }
          i += MENU_ITEMS_PANE_LENGTH;

          /* Find the width of the widest item in this pane.  */
          maxwidth = 0;
          j = i;
          while (j < menu_items_used)
            {
              Lisp_Object item;
              item = XVECTOR (menu_items)->contents[j];
              if (EQ (item, Qt))
                break;
              if (NILP (item))
                {
                  j++;
                  continue;
                }
              width = STRING_BYTES (XSTRING (item));
              if (width > maxwidth)
                maxwidth = width;

              j += MENU_ITEMS_ITEM_LENGTH;
            }
        }
      /* Ignore a nil in the item list.
         It's meaningful only for dialog boxes.  */
      else if (EQ (XVECTOR (menu_items)->contents[i], Qquote))
        i += 1;
      else
        {
          /* Create a new item within current pane.  */
          Lisp_Object item_name, enable, descrip, help;
          unsigned char *item_data;
          char *help_string;

          item_name = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_NAME];
          enable = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_ENABLE];
          descrip
            = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_EQUIV_KEY];
          help = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_HELP];
          help_string = STRINGP (help) ? XSTRING (help)->data : NULL;
          
          if (!NILP (descrip))
            {
              int gap = maxwidth - STRING_BYTES (XSTRING (item_name));
#ifdef C_ALLOCA
              Lisp_Object spacer;
              spacer = Fmake_string (make_number (gap), make_number (' '));
              item_name = concat2 (item_name, spacer);
              item_name = concat2 (item_name, descrip);
              item_data = XSTRING (item_name)->data;
#else
              /* if alloca is fast, use that to make the space,
                 to reduce gc needs.  */
              item_data
                = (unsigned char *) alloca (maxwidth
                                            + STRING_BYTES (XSTRING (descrip)) + 1);
              bcopy (XSTRING (item_name)->data, item_data,
                     STRING_BYTES (XSTRING (item_name)));
              for (j = XSTRING (item_name)->size; j < maxwidth; j++)
                item_data[j] = ' ';
              bcopy (XSTRING (descrip)->data, item_data + j,
                     STRING_BYTES (XSTRING (descrip)));
              item_data[j + STRING_BYTES (XSTRING (descrip))] = 0;
#endif
            }
          else
            item_data = XSTRING (item_name)->data;

          if (XMenuAddSelection (FRAME_X_DISPLAY (f),
                                 menu, lpane, 0, item_data,
                                 !NILP (enable), help_string)
              == XM_FAILURE)
            {
              XMenuDestroy (FRAME_X_DISPLAY (f), menu);
              *error = "Can't add selection to menu";
              return Qnil;
            }
          i += MENU_ITEMS_ITEM_LENGTH;
        }
    }

  /* All set and ready to fly.  */
  XMenuRecompute (FRAME_X_DISPLAY (f), menu);
  dispwidth = DisplayWidth (FRAME_X_DISPLAY (f),
                            XScreenNumberOfScreen (FRAME_X_SCREEN (f)));
  dispheight = DisplayHeight (FRAME_X_DISPLAY (f),
                              XScreenNumberOfScreen (FRAME_X_SCREEN (f)));
  x = min (x, dispwidth);
  y = min (y, dispheight);
  x = max (x, 1);
  y = max (y, 1);
  XMenuLocate (FRAME_X_DISPLAY (f), menu, 0, 0, x, y,
               &ulx, &uly, &width, &height);
  if (ulx+width > dispwidth)
    {
      x -= (ulx + width) - dispwidth;
      ulx = dispwidth - width;
    }
  if (uly+height > dispheight)
    {
      y -= (uly + height) - dispheight;
      uly = dispheight - height;
    }
  if (ulx < 0) x -= ulx;
  if (uly < 0) y -= uly;

  XMenuSetAEQ (menu, TRUE);
  XMenuSetFreeze (menu, TRUE);
  pane = selidx = 0;

  /* Help display under X won't work because XMenuActivate contains
     a loop that doesn't give Emacs a chance to process it.  */
  menu_help_frame = f;
  status = XMenuActivate (FRAME_X_DISPLAY (f), menu, &pane, &selidx,
                          x, y, ButtonReleaseMask, &datap,
                          menu_help_callback);


#ifdef HAVE_X_WINDOWS
  /* Assume the mouse has moved out of the X window.
     If it has actually moved in, we will get an EnterNotify.  */
  x_mouse_leave (FRAME_X_DISPLAY_INFO (f));
#endif

  switch (status)
    {
    case XM_SUCCESS:
#ifdef XDEBUG
      fprintf (stderr, "pane= %d line = %d\n", panes, selidx);
#endif

      /* Find the item number SELIDX in pane number PANE.  */
      i = 0;
      while (i < menu_items_used)
        {
          if (EQ (XVECTOR (menu_items)->contents[i], Qt))
            {
              if (pane == 0)
                pane_prefix
                  = XVECTOR (menu_items)->contents[i + MENU_ITEMS_PANE_PREFIX];
              pane--;
              i += MENU_ITEMS_PANE_LENGTH;
            }
          else
            {
              if (pane == -1)
                {
                  if (selidx == 0)
                    {
                      entry
                        = XVECTOR (menu_items)->contents[i + MENU_ITEMS_ITEM_VALUE];
                      if (keymaps != 0)
                        {
                          entry = Fcons (entry, Qnil);
                          if (!NILP (pane_prefix))
                            entry = Fcons (pane_prefix, entry);
                        }
                      break;
                    }
                  selidx--;
                }
              i += MENU_ITEMS_ITEM_LENGTH;
            }
        }
      break;

    case XM_FAILURE:
      *error = "Can't activate menu";
    case XM_IA_SELECT:
    case XM_NO_SELECT:
      entry = Qnil;
      break;
    }
  XMenuDestroy (FRAME_X_DISPLAY (f), menu);

#ifdef HAVE_X_WINDOWS
  /* State that no mouse buttons are now held.
     (The oldXMenu code doesn't track this info for us.)
     That is not necessarily true, but the fiction leads to reasonable
     results, and it is a pain to ask which are actually held now.  */
  FRAME_X_DISPLAY_INFO (f)->grabbed = 0;
#endif

  return entry;
}

#endif /* not USE_X_TOOLKIT */

#endif /* HAVE_MENUS */
\f
void
syms_of_xmenu ()
{
  staticpro (&menu_items);
  menu_items = Qnil;

  Qdebug_on_next_call = intern ("debug-on-next-call");
  staticpro (&Qdebug_on_next_call);

  DEFVAR_LISP ("menu-updating-frame", &Vmenu_updating_frame,
    "Frame for which we are updating a menu.\n\
The enable predicate for a menu command should check this variable.");
  Vmenu_updating_frame = Qnil;

#ifdef USE_X_TOOLKIT
  widget_id_tick = (1<<16);     
  next_menubar_widget_id = 1;
#endif

  defsubr (&Sx_popup_menu);
#ifdef HAVE_MENUS
  defsubr (&Sx_popup_dialog);
#endif
}