This commit was generated by cvs2svn to compensate for changes in r6453,

[chise/xemacs-chise.git.1] / info / lispref.info-19

This is Info file ../../info/lispref.info, produced by Makeinfo version
1.68 from the input file lispref.texi.

INFO-DIR-SECTION XEmacs Editor
START-INFO-DIR-ENTRY
* Lispref: (lispref).           XEmacs Lisp Reference Manual.
END-INFO-DIR-ENTRY

   Edition History:

   GNU Emacs Lisp Reference Manual Second Edition (v2.01), May 1993 GNU
Emacs Lisp Reference Manual Further Revised (v2.02), August 1993 Lucid
Emacs Lisp Reference Manual (for 19.10) First Edition, March 1994
XEmacs Lisp Programmer's Manual (for 19.12) Second Edition, April 1995
GNU Emacs Lisp Reference Manual v2.4, June 1995 XEmacs Lisp
Programmer's Manual (for 19.13) Third Edition, July 1995 XEmacs Lisp
Reference Manual (for 19.14 and 20.0) v3.1, March 1996 XEmacs Lisp
Reference Manual (for 19.15 and 20.1, 20.2, 20.3) v3.2, April, May,
November 1997 XEmacs Lisp Reference Manual (for 21.0) v3.3, April 1998

   Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995 Free Software
Foundation, Inc.  Copyright (C) 1994, 1995 Sun Microsystems, Inc.
Copyright (C) 1995, 1996 Ben Wing.

   Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that this permission notice may be stated in a
translation approved by the Foundation.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided also
that the section entitled "GNU General Public License" is included
exactly as in the original, and provided that the entire resulting
derived work is distributed under the terms of a permission notice
identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that the section entitled "GNU General Public License"
may be included in a translation approved by the Free Software
Foundation instead of in the original English.

\1f
File: lispref.info,  Node: Key Lookup,  Next: Functions for Key Lookup,  Prev: Active Keymaps,  Up: Keymaps

Key Lookup
==========

   "Key lookup" is the process of finding the binding of a key sequence
from a given keymap.  Actual execution of the binding is not part of
key lookup.

   Key lookup uses just the event type of each event in the key
sequence; the rest of the event is ignored.  In fact, a key sequence
used for key lookup may designate mouse events with just their types
(symbols) instead of with entire mouse events (lists).  *Note Events::.
Such a pseudo-key-sequence is insufficient for `command-execute', but
it is sufficient for looking up or rebinding a key.

   When the key sequence consists of multiple events, key lookup
processes the events sequentially: the binding of the first event is
found, and must be a keymap; then the second event's binding is found in
that keymap, and so on until all the events in the key sequence are used
up.  (The binding thus found for the last event may or may not be a
keymap.)  Thus, the process of key lookup is defined in terms of a
simpler process for looking up a single event in a keymap.  How that is
done depends on the type of object associated with the event in that
keymap.

   Let's use the term "keymap entry" to describe the value found by
looking up an event type in a keymap.  (This doesn't include the item
string and other extra elements in menu key bindings because
`lookup-key' and other key lookup functions don't include them in the
returned value.)  While any Lisp object may be stored in a keymap as a
keymap entry, not all make sense for key lookup.  Here is a list of the
meaningful kinds of keymap entries:

`nil'
     `nil' means that the events used so far in the lookup form an
     undefined key.  When a keymap fails to mention an event type at
     all, and has no default binding, that is equivalent to a binding
     of `nil' for that event type.

KEYMAP
     The events used so far in the lookup form a prefix key.  The next
     event of the key sequence is looked up in KEYMAP.

COMMAND
     The events used so far in the lookup form a complete key, and
     COMMAND is its binding.  *Note What Is a Function::.

ARRAY
     The array (either a string or a vector) is a keyboard macro.  The
     events used so far in the lookup form a complete key, and the
     array is its binding.  See *Note Keyboard Macros::, for more
     information. (Note that you cannot use a shortened form of a key
     sequence here, such as `(control y)'; you must use the full form
     `[(control y)]'.  *Note Key Sequences::.)

LIST
     The meaning of a list depends on the types of the elements of the
     list.

        * If the CAR of LIST is `lambda', then the list is a lambda
          expression.  This is presumed to be a command, and is treated
          as such (see above).

        * If the CAR of LIST is a keymap and the CDR is an event type,
          then this is an "indirect entry":

               (OTHERMAP . OTHERTYPE)

          When key lookup encounters an indirect entry, it looks up
          instead the binding of OTHERTYPE in OTHERMAP and uses that.

          This feature permits you to define one key as an alias for
          another key.  For example, an entry whose CAR is the keymap
          called `esc-map' and whose CDR is 32 (the code for <SPC>)
          means, "Use the global binding of `Meta-<SPC>', whatever that
          may be."

SYMBOL
     The function definition of SYMBOL is used in place of SYMBOL.  If
     that too is a symbol, then this process is repeated, any number of
     times.  Ultimately this should lead to an object that is a keymap,
     a command or a keyboard macro.  A list is allowed if it is a
     keymap or a command, but indirect entries are not understood when
     found via symbols.

     Note that keymaps and keyboard macros (strings and vectors) are not
     valid functions, so a symbol with a keymap, string, or vector as
     its function definition is invalid as a function.  It is, however,
     valid as a key binding.  If the definition is a keyboard macro,
     then the symbol is also valid as an argument to `command-execute'
     (*note Interactive Call::.).

     The symbol `undefined' is worth special mention: it means to treat
     the key as undefined.  Strictly speaking, the key is defined, and
     its binding is the command `undefined'; but that command does the
     same thing that is done automatically for an undefined key: it
     rings the bell (by calling `ding') but does not signal an error.

     `undefined' is used in local keymaps to override a global key
     binding and make the key "undefined" locally.  A local binding of
     `nil' would fail to do this because it would not override the
     global binding.

ANYTHING ELSE
     If any other type of object is found, the events used so far in the
     lookup form a complete key, and the object is its binding, but the
     binding is not executable as a command.

   In short, a keymap entry may be a keymap, a command, a keyboard
macro, a symbol that leads to one of them, or an indirection or `nil'.

\1f
File: lispref.info,  Node: Functions for Key Lookup,  Next: Changing Key Bindings,  Prev: Key Lookup,  Up: Keymaps

Functions for Key Lookup
========================

   Here are the functions and variables pertaining to key lookup.

 - Function: lookup-key KEYMAP KEY &optional ACCEPT-DEFAULTS
     This function returns the definition of KEY in KEYMAP.  If the
     string or vector KEY is not a valid key sequence according to the
     prefix keys specified in KEYMAP (which means it is "too long" and
     has extra events at the end), then the value is a number, the
     number of events at the front of KEY that compose a complete key.

     If ACCEPT-DEFAULTS is non-`nil', then `lookup-key' considers
     default bindings as well as bindings for the specific events in
     KEY.  Otherwise, `lookup-key' reports only bindings for the
     specific sequence KEY, ignoring default bindings except when you
     explicitly ask about them.

     All the other functions described in this chapter that look up
     keys use `lookup-key'.

          (lookup-key (current-global-map) "\C-x\C-f")
              => find-file
          (lookup-key (current-global-map) "\C-x\C-f12345")
              => 2

     If KEY begins with the character whose value is contained in
     `meta-prefix-char', that character is implicitly removed and the
     <META> modifier added to the key.  Thus, the first example below is
     handled by conversion into the second example.

          (lookup-key (current-global-map) "\ef")
              => forward-word
          (lookup-key (current-global-map) "\M-f")
              => forward-word

     Unlike `read-key-sequence', this function does not modify the
     specified events in ways that discard information (*note Key
     Sequence Input::.).  In particular, it does not convert letters to
     lower case.

 - Command: undefined
     Used in keymaps to undefine keys.  If a key sequence is defined to
     this, invoking this key sequence causes a "key undefined" error,
     just as if the key sequence had no binding.

 - Function: key-binding KEY &optional ACCEPT-DEFAULTS
     This function returns the binding for KEY in the current keymaps,
     trying all the active keymaps.  The result is `nil' if KEY is
     undefined in the keymaps.

     The argument ACCEPT-DEFAULTS controls checking for default
     bindings, as in `lookup-key' (above).

          (key-binding "\C-x\C-f")
              => find-file
          (key-binding '(control home))
              => beginning-of-buffer
          (key-binding [escape escape escape])
              => keyboard-escape-quit

 - Function: local-key-binding KEY &optional ACCEPT-DEFAULTS
     This function returns the binding for KEY in the current local
     keymap, or `nil' if it is undefined there.

     The argument ACCEPT-DEFAULTS controls checking for default
     bindings, as in `lookup-key' (above).

 - Function: global-key-binding KEY &optional ACCEPT-DEFAULTS
     This function returns the binding for command KEY in the current
     global keymap, or `nil' if it is undefined there.

     The argument ACCEPT-DEFAULTS controls checking for default
     bindings, as in `lookup-key' (above).

 - Function: minor-mode-key-binding KEY &optional ACCEPT-DEFAULTS
     This function returns a list of all the active minor mode bindings
     of KEY.  More precisely, it returns an alist of pairs `(MODENAME .
     BINDING)', where MODENAME is the variable that enables the minor
     mode, and BINDING is KEY's binding in that mode.  If KEY has no
     minor-mode bindings, the value is `nil'.

     If the first binding is not a prefix command, all subsequent
     bindings from other minor modes are omitted, since they would be
     completely shadowed.  Similarly, the list omits non-prefix
     bindings that follow prefix bindings.

     The argument ACCEPT-DEFAULTS controls checking for default
     bindings, as in `lookup-key' (above).

 - Variable: meta-prefix-char
     This variable is the meta-prefix character code.  It is used when
     translating a two-character sequence to a meta character so it can
     be looked up in a keymap.  For useful results, the value should be
     a prefix event (*note Prefix Keys::.).  The default value is
     `?\^[' (integer 27), which is the ASCII character usually produced
     by the <ESC> key.

     As long as the value of `meta-prefix-char' remains `?\^[', key
     lookup translates `<ESC> b' into `M-b', which is normally defined
     as the `backward-word' command.  However, if you set
     `meta-prefix-char' to `?\^X' (i.e. the keystroke `C-x') or its
     equivalent ASCII code `24', then XEmacs will translate `C-x b'
     (whose standard binding is the `switch-to-buffer' command) into
     `M-b'.

          meta-prefix-char                    ; The default value.
               => ?\^[   ; Under XEmacs 20.
               => 27     ; Under XEmacs 19.

          (key-binding "\eb")
               => backward-word

          ?\C-x                               ; The print representation
                                                     ;   of a character.
               => ?\^X   ; Under XEmacs 20.
               => 24     ; Under XEmacs 19.

          (setq meta-prefix-char 24)
               => 24

          (key-binding "\C-xb")
               => backward-word            ; Now, typing `C-x b' is
                                              ;   like typing `M-b'.
          
          (setq meta-prefix-char ?\e)          ; Avoid confusion!
                                               ; Restore the default value!
               => ?\^[   ; Under XEmacs 20.
               => 27     ; Under XEmacs 19.

\1f
File: lispref.info,  Node: Changing Key Bindings,  Next: Key Binding Commands,  Prev: Functions for Key Lookup,  Up: Keymaps

Changing Key Bindings
=====================

   The way to rebind a key is to change its entry in a keymap.  If you
change a binding in the global keymap, the change is effective in all
buffers (though it has no direct effect in buffers that shadow the
global binding with a local one).  If you change the current buffer's
local map, that usually affects all buffers using the same major mode.
The `global-set-key' and `local-set-key' functions are convenient
interfaces for these operations (*note Key Binding Commands::.).  You
can also use `define-key', a more general function; then you must
specify explicitly the map to change.

   The way to specify the key sequence that you want to rebind is
described above (*note Key Sequences::.).

   For the functions below, an error is signaled if KEYMAP is not a
keymap or if KEY is not a string or vector representing a key sequence.
You can use event types (symbols) as shorthand for events that are
lists.

 - Function: define-key KEYMAP KEY BINDING
     This function sets the binding for KEY in KEYMAP.  (If KEY is more
     than one event long, the change is actually made in another keymap
     reached from KEYMAP.)  The argument BINDING can be any Lisp
     object, but only certain types are meaningful.  (For a list of
     meaningful types, see *Note Key Lookup::.)  The value returned by
     `define-key' is BINDING.

     Every prefix of KEY must be a prefix key (i.e., bound to a keymap)
     or undefined; otherwise an error is signaled.

     If some prefix of KEY is undefined, then `define-key' defines it
     as a prefix key so that the rest of KEY may be defined as
     specified.

   Here is an example that creates a sparse keymap and makes a number of
bindings in it:

     (setq map (make-sparse-keymap))
         => #<keymap 0 entries 0xbee>

     (define-key map "\C-f" 'forward-char)
         => forward-char

     map
         => #<keymap 1 entry 0xbee>
     (describe-bindings-internal map)
     =>   ; (Inserted in buffer)
     C-f             forward-char

     ;; Build sparse submap for `C-x' and bind `f' in that.
     (define-key map "\C-xf" 'forward-word)
         => forward-word

     map
         => #<keymap 2 entries 0xbee>
     (describe-bindings-internal map)
     =>   ; (Inserted in buffer)
     C-f             forward-char
     C-x             << Prefix Command >>
     
     C-x f           forward-word

     ;; Bind `C-p' to the `ctl-x-map'.
     (define-key map "\C-p" ctl-x-map)
     ;; `ctl-x-map'
     => #<keymap Control-X-prefix 77 entries 0x3bf>

     ;; Bind `C-f' to `foo' in the `ctl-x-map'.
     (define-key map "\C-p\C-f" 'foo)
     => foo

     map
         => #<keymap 3 entries 0xbee>
     (describe-bindings-internal map)
     =>   ; (Inserted in buffer)
     C-f             forward-char
     C-p             << Prefix command Control-X-prefix >>
     C-x             << Prefix Command >>
     
     C-p tab         indent-rigidly
     C-p $           set-selective-display
     C-p '           expand-abbrev
     C-p (           start-kbd-macro
     C-p )           end-kbd-macro
        ...
     C-p C-x         exchange-point-and-mark
     C-p C-z         suspend-or-iconify-emacs
     C-p M-escape    repeat-complex-command
     C-p M-C-[       repeat-complex-command
     
     C-x f           forward-word
     
     C-p 4 .         find-tag-other-window
        ...
     C-p 4 C-o       display-buffer
     
     C-p 5 0         delete-frame
        ...
     C-p 5 C-f       find-file-other-frame
     
        ...
     
     C-p a i g       inverse-add-global-abbrev
     C-p a i l       inverse-add-mode-abbrev

Note that storing a new binding for `C-p C-f' actually works by
changing an entry in `ctl-x-map', and this has the effect of changing
the bindings of both `C-p C-f' and `C-x C-f' in the default global map.

 - Function: substitute-key-definition OLDDEF NEWDEF KEYMAP &optional
          OLDMAP
     This function replaces OLDDEF with NEWDEF for any keys in KEYMAP
     that were bound to OLDDEF.  In other words, OLDDEF is replaced
     with NEWDEF wherever it appears.  The function returns `nil'.

     For example, this redefines `C-x C-f', if you do it in an XEmacs
     with standard bindings:

          (substitute-key-definition
           'find-file 'find-file-read-only (current-global-map))

     If OLDMAP is non-`nil', then its bindings determine which keys to
     rebind.  The rebindings still happen in NEWMAP, not in OLDMAP.
     Thus, you can change one map under the control of the bindings in
     another.  For example,

          (substitute-key-definition
            'delete-backward-char 'my-funny-delete
            my-map global-map)

     puts the special deletion command in `my-map' for whichever keys
     are globally bound to the standard deletion command.


 - Function: suppress-keymap KEYMAP &optional NODIGITS
     This function changes the contents of the full keymap KEYMAP by
     making all the printing characters undefined.  More precisely, it
     binds them to the command `undefined'.  This makes ordinary
     insertion of text impossible.  `suppress-keymap' returns `nil'.

     If NODIGITS is `nil', then `suppress-keymap' defines digits to run
     `digit-argument', and `-' to run `negative-argument'.  Otherwise
     it makes them undefined like the rest of the printing characters.

     The `suppress-keymap' function does not make it impossible to
     modify a buffer, as it does not suppress commands such as `yank'
     and `quoted-insert'.  To prevent any modification of a buffer, make
     it read-only (*note Read Only Buffers::.).

     Since this function modifies KEYMAP, you would normally use it on
     a newly created keymap.  Operating on an existing keymap that is
     used for some other purpose is likely to cause trouble; for
     example, suppressing `global-map' would make it impossible to use
     most of XEmacs.

     Most often, `suppress-keymap' is used to initialize local keymaps
     of modes such as Rmail and Dired where insertion of text is not
     desirable and the buffer is read-only.  Here is an example taken
     from the file `emacs/lisp/dired.el', showing how the local keymap
     for Dired mode is set up:

          ...
            (setq dired-mode-map (make-keymap))
            (suppress-keymap dired-mode-map)
            (define-key dired-mode-map "r" 'dired-rename-file)
            (define-key dired-mode-map "\C-d" 'dired-flag-file-deleted)
            (define-key dired-mode-map "d" 'dired-flag-file-deleted)
            (define-key dired-mode-map "v" 'dired-view-file)
            (define-key dired-mode-map "e" 'dired-find-file)
            (define-key dired-mode-map "f" 'dired-find-file)
            ...

\1f
File: lispref.info,  Node: Key Binding Commands,  Next: Scanning Keymaps,  Prev: Changing Key Bindings,  Up: Keymaps

Commands for Binding Keys
=========================

   This section describes some convenient interactive interfaces for
changing key bindings.  They work by calling `define-key'.

   People often use `global-set-key' in their `.emacs' file for simple
customization.  For example,

     (global-set-key "\C-x\C-\\" 'next-line)

or

     (global-set-key [(control ?x) (control ?\\)] 'next-line)

or

     (global-set-key [?\C-x ?\C-\\] 'next-line)

redefines `C-x C-\' to move down a line.

     (global-set-key [(meta button1)] 'mouse-set-point)

redefines the first (leftmost) mouse button, typed with the Meta key, to
set point where you click.

 - Command: global-set-key KEY DEFINITION
     This function sets the binding of KEY in the current global map to
     DEFINITION.

          (global-set-key KEY DEFINITION)
          ==
          (define-key (current-global-map) KEY DEFINITION)

 - Command: global-unset-key KEY
     This function removes the binding of KEY from the current global
     map.

     One use of this function is in preparation for defining a longer
     key that uses KEY as a prefix--which would not be allowed if KEY
     has a non-prefix binding.  For example:

          (global-unset-key "\C-l")
              => nil

          (global-set-key "\C-l\C-l" 'redraw-display)
              => nil

     This function is implemented simply using `define-key':

          (global-unset-key KEY)
          ==
          (define-key (current-global-map) KEY nil)

 - Command: local-set-key KEY DEFINITION
     This function sets the binding of KEY in the current local keymap
     to DEFINITION.

          (local-set-key KEY DEFINITION)
          ==
          (define-key (current-local-map) KEY DEFINITION)

 - Command: local-unset-key KEY
     This function removes the binding of KEY from the current local
     map.

          (local-unset-key KEY)
          ==
          (define-key (current-local-map) KEY nil)

\1f
File: lispref.info,  Node: Scanning Keymaps,  Next: Other Keymap Functions,  Prev: Key Binding Commands,  Up: Keymaps

Scanning Keymaps
================

   This section describes functions used to scan all the current
keymaps, or all keys within a keymap, for the sake of printing help
information.

 - Function: accessible-keymaps KEYMAP &optional PREFIX
     This function returns a list of all the keymaps that can be
     accessed (via prefix keys) from KEYMAP.  The value is an
     association list with elements of the form `(KEY . MAP)', where
     KEY is a prefix key whose definition in KEYMAP is MAP.

     The elements of the alist are ordered so that the KEY increases in
     length.  The first element is always `([] . KEYMAP)', because the
     specified keymap is accessible from itself with a prefix of no
     events.

     If PREFIX is given, it should be a prefix key sequence; then
     `accessible-keymaps' includes only the submaps whose prefixes start
     with PREFIX.  These elements look just as they do in the value of
     `(accessible-keymaps)'; the only difference is that some elements
     are omitted.

     In the example below, the returned alist indicates that the key
     `C-x', which is displayed as `[(control x)]', is a prefix key
     whose definition is the keymap `#<keymap ((control x) #<keymap
     emacs-lisp-mode-map 8 entries 0x546>) 1 entry 0x8a2>'. (The strange
     notation for the keymap's name indicates that this is an internal
     submap of `emacs-lisp-mode-map'.  This is because
     `lisp-interaction-mode-map' has set up `emacs-lisp-mode-map' as
     its parent, and `lisp-interaction-mode-map' defines no key
     sequences beginning with `C-x'.)

          (current-local-map)
          => #<keymap lisp-interaction-mode-map 5 entries 0x558>
          (accessible-keymaps (current-local-map))
          =>(([] . #<keymap lisp-interaction-mode-map 5 entries 0x558>)
              ([(control x)] .
               #<keymap ((control x) #<keymap emacs-lisp-mode-map 8 entries 0x546>)
                        1 entry 0x8a2>))

     The following example shows the results of calling
     `accessible-keymaps' on a large, complex keymap.  Notice how some
     keymaps were given explicit names using `set-keymap-name'; those
     submaps without explicit names are given descriptive names
     indicating their relationship to their enclosing keymap.

          (accessible-keymaps (current-global-map))
          => (([] . #<keymap global-map 639 entries 0x221>)
             ([(control c)] . #<keymap mode-specific-command-prefix 1 entry 0x3cb>)
             ([(control h)] . #<keymap help-map 33 entries 0x4ec>)
             ([(control x)] . #<keymap Control-X-prefix 77 entries 0x3bf>)
             ([(meta escape)] .
                #<keymap ((meta escape) #<keymap global-map 639 entries 0x221>)
                         3 entries 0x3e0>)
             ([(meta control \[)] .
                #<keymap ((meta escape) #<keymap global-map 639 entries 0x221>)
                         3 entries 0x3e0>)
             ([f1] . #<keymap help-map 33 entries 0x4ec>)
             ([(control x) \4] . #<keymap ctl-x-4-prefix 9 entries 0x3c5>)
             ([(control x) \5] . #<keymap ctl-x-5-prefix 8 entries 0x3c8>)
             ([(control x) \6] . #<keymap 13 entries 0x4d2>)
             ([(control x) a] .
                #<keymap (a #<keymap Control-X-prefix 77 entries 0x3bf>)
                         8 entries 0x3ef>)
             ([(control x) n] . #<keymap narrowing-prefix 3 entries 0x3dd>)
             ([(control x) r] . #<keymap rectangle-prefix 18 entries 0x3e9>)
             ([(control x) v] . #<keymap vc-prefix-map 13 entries 0x60e>)
             ([(control x) a i] .
               #<keymap (i #<keymap (a #<keymap Control-X-prefix 77 entries 0x3bf>)
                                    8 entries 0x3ef>)
                        2 entries 0x3f5>))

 - Function: map-keymap FUNCTION KEYMAP &optional SORT-FIRST
     This function applies FUNCTION to each element of `KEYMAP'.
     FUNCTION will be called with two arguments: a key-description
     list, and the binding.  The order in which the elements of the
     keymap are passed to the function is unspecified.  If the function
     inserts new elements into the keymap, it may or may not be called
     with them later.  No element of the keymap will ever be passed to
     the function more than once.

     The function will not be called on elements of this keymap's
     parents (*note Inheritance and Keymaps::.) or upon keymaps which
     are contained within this keymap (multi-character definitions).
     It will be called on <META> characters since they are not really
     two-character sequences.

     If the optional third argument SORT-FIRST is non-`nil', then the
     elements of the keymap will be passed to the mapper function in a
     canonical order.  Otherwise, they will be passed in hash (that is,
     random) order, which is faster.

 - Function: keymap-fullness KEYMAP
     This function returns the number of bindings in the keymap.

 - Function: where-is-internal DEFINITION &optional KEYMAPS FIRSTONLY
          NOINDIRECT EVENT-OR-KEYS
     This function returns a list of key sequences (of any length) that
     are bound to DEFINITION in a set of keymaps.

     The argument DEFINITION can be any object; it is compared with all
     keymap entries using `eq'.

     KEYMAPS can be either a keymap (meaning search in that keymap and
     the current global keymap) or a list of keymaps (meaning search in
     exactly those keymaps and no others).  If KEYMAPS is nil, search
     in the currently applicable maps for EVENT-OR-KEYS.

     If KEYMAP is a keymap, then the maps searched are KEYMAP and the
     global keymap.  If KEYMAP is a list of keymaps, then the maps
     searched are exactly those keymaps, and no others.  If KEYMAP is
     `nil', then the maps used are the current active keymaps for
     EVENT-OR-KEYS (this is equivalent to specifying `(current-keymaps
     EVENT-OR-KEYS)' as the argument to KEYMAPS).

     If FIRSTONLY is non-`nil', then the value is a single vector
     representing the first key sequence found, rather than a list of
     all possible key sequences.

     If NOINDIRECT is non-`nil', `where-is-internal' doesn't follow
     indirect keymap bindings.  This makes it possible to search for an
     indirect definition itself.

     This function is used by `where-is' (*note Help: (emacs)Help.).

          (where-is-internal 'describe-function)
              => ([(control h) d] [(control h) f] [f1 d] [f1 f])

 - Function: describe-bindings-internal MAP &optional ALL SHADOW PREFIX
          MOUSE-ONLY-P
     This function inserts (into the current buffer) a list of all
     defined keys and their definitions in MAP.  Optional second
     argument ALL says whether to include even "uninteresting"
     definitions, i.e.  symbols with a non-`nil' `suppress-keymap'
     property.  Third argument SHADOW is a list of keymaps whose
     bindings shadow those of map; if a binding is present in any
     shadowing map, it is not printed.  Fourth argument PREFIX, if
     non-`nil', should be a key sequence; only bindings which start
     with that key sequence will be printed.  Fifth argument
     MOUSE-ONLY-P says to only print bindings for mouse clicks.

   `describe-bindings-internal' is used to implement the help command
`describe-bindings'.

 - Command: describe-bindings PREFIX MOUSE-ONLY-P
     This function creates a listing of all defined keys and their
     definitions.  It writes the listing in a buffer named `*Help*' and
     displays it in a window.

     If PREFIX is non-`nil', it should be a prefix key; then the
     listing includes only keys that start with PREFIX.

     When several characters with consecutive ASCII codes have the same
     definition, they are shown together, as `FIRSTCHAR..LASTCHAR'.  In
     this instance, you need to know the ASCII codes to understand
     which characters this means.  For example, in the default global
     map, the characters `<SPC> .. ~' are described by a single line.
     <SPC> is ASCII 32, `~' is ASCII 126, and the characters between
     them include all the normal printing characters, (e.g., letters,
     digits, punctuation, etc.); all these characters are bound to
     `self-insert-command'.

     If the second argument (prefix arg, interactively) is non-`nil'
     then only the mouse bindings are displayed.

\1f
File: lispref.info,  Node: Other Keymap Functions,  Prev: Scanning Keymaps,  Up: Keymaps

Other Keymap Functions
======================

 - Function: set-keymap-prompt KEYMAP NEW-PROMPT
     This function sets the "prompt" of KEYMAP to string NEW-PROMPT, or
     `nil' if no prompt is desired.  The prompt is shown in the
     echo-area when reading a key-sequence to be looked-up in this
     keymap.

 - Function: keymap-prompt KEYMAP &optional USE-INHERITED
     This function returns the "prompt" of the given keymap.  If
     USE-INHERITED is non-`nil', any parent keymaps will also be
     searched for a prompt.

\1f
File: lispref.info,  Node: Menus,  Next: Dialog Boxes,  Prev: Keymaps,  Up: Top

Menus
*****

* Menu:

* Menu Format::         Format of a menu description.
* Menubar Format::      How to specify a menubar.
* Menubar::             Functions for controlling the menubar.
* Modifying Menus::     Modifying a menu description.
* Pop-Up Menus::        Functions for specifying pop-up menus.
* Menu Filters::        Filter functions for the default menubar.
* Menu Accelerators::   Using and controlling menu accelerator keys
* Buffers Menu::        The menu that displays the list of buffers.

\1f
File: lispref.info,  Node: Menu Format,  Next: Menubar Format,  Up: Menus

Format of Menus
===============

   A menu is described using a "menu description", which is a list of
menu items, keyword-value pairs, strings, and submenus.  The menu
description specifies which items are present in the menu, what function
each item invokes, and whether the item is selectable or not.  Pop-up
menus are directly described with a menu description, while menubars are
described slightly differently (see below).

   The first element of a menu must be a string, which is the name of
the menu.  This is the string that will be displayed in the parent menu
or menubar, if any.  This string is not displayed in the menu itself,
except in the case of the top level pop-up menu, where there is no
parent.  In this case, the string will be displayed at the top of the
menu if `popup-menu-titles' is non-`nil'.

   Immediately following the first element there may optionally be up
to four keyword-value pairs, as follows:

`:included FORM'
     This can be used to control the visibility of a menu.  The form is
     evaluated and the menu will be omitted if the result is `nil'.

`:config SYMBOL'
     This is an efficient shorthand for `:included (memq SYMBOL
     menubar-configuration)'.  See the variable `menubar-configuration'.

`:filter FUNCTION'
     A menu filter is used to sensitize or incrementally create a
     submenu only when it is selected by the user and not every time
     the menubar is activated.  The filter function is passed the list
     of menu items in the submenu and must return a list of menu items
     to be used for the menu.  It is called only when the menu is about
     to be displayed, so other menus may already be displayed.  Vile
     and terrible things will happen if a menu filter function changes
     the current buffer, window, or frame.  It also should not raise,
     lower, or iconify any frames.  Basically, the filter function
     should have no side-effects.

`:accelerator KEY'
     A menu accelerator is a keystroke which can be pressed while the
     menu is visible which will immediately activate the item.  KEY
     must be a char or the symbol name of a key.  *Note Menu
     Accelerators::.

   The rest of the menu consists of elements as follows:

   * A "menu item", which is a vector in the following form:

          `[ NAME CALLBACK :KEYWORD VALUE :KEYWORD VALUE ... ]'

     NAME is a string, the name of the menu item; it is the string to
     display on the menu.  It is filtered through the resource
     database, so it is possible for resources to override what string
     is actually displayed.

     CALLBACK is a form that will be invoked when the menu item is
     selected.  If the callback of a menu item is a symbol, then it
     must name a command.  It will be invoked with
     `call-interactively'.  If it is a list, then it is evaluated with
     `eval'.

     The valid keywords and their meanings are described below.

     Note that for compatibility purposes, the form

          `[ NAME CALLBACK ACTIVE-P ]'

     is also accepted and is equivalent to

          `[ NAME CALLBACK :active ACTIVE-P ]'

     and the form

          `[ NAME CALLBACK ACTIVE-P SUFFIX]'

     is accepted and is equivalent to

          `[ NAME CALLBACK :active ACTIVE-P :suffix SUFFIX]'

     However, these older forms are deprecated and should generally not
     be used.

   * If an element of a menu is a string, then that string will be
     presented in the menu as unselectable text.

   * If an element of a menu is a string consisting solely of hyphens,
     then that item will be presented as a solid horizontal line.

   * If an element of a menu is a string beginning with `--:', then a
     particular sort of horizontal line will be displayed, as follows:

    `"--:singleLine"'
          A solid horizontal line.  This is equivalent to a string
          consisting solely of hyphens.

    `"--:doubleLine"'
          A solid double horizontal line.

    `"--:singleDashedLine"'
          A dashed horizontal line.

    `"--:doubleDashedLine"'
          A dashed double horizontal line.

    `"--:noLine"'
          No line (but a small space is left).

    `"--:shadowEtchedIn"'
          A solid horizontal line with a 3-d recessed appearance.

    `"--:shadowEtchedOut"'
          A solid horizontal line with a 3-d pushed-out appearance.

    `"--:shadowDoubleEtchedIn"'
          A solid double horizontal line with a 3-d recessed appearance.

    `"--:shadowDoubleEtchedOut"'
          A solid double horizontal line with a 3-d pushed-out
          appearance.

    `"--:shadowEtchedInDash"'
          A dashed horizontal line with a 3-d recessed appearance.

    `"--:shadowEtchedOutDash"'
          A dashed horizontal line with a 3-d pushed-out appearance.

    `"--:shadowDoubleEtchedInDash"'
          A dashed double horizontal line with a 3-d recessed
          appearance.

    `"--:shadowDoubleEtchedOutDash"'
          A dashed double horizontal line with a 3-d pushed-out
          appearance.

   * If an element of a menu is a list, it is treated as a submenu.
     The name of that submenu (the first element in the list) will be
     used as the name of the item representing this menu on the parent.

   The possible keywords are as follows:

:active FORM
     FORM will be evaluated when the menu that this item is a part of
     is about to be displayed, and the item will be selectable only if
     the result is non-`nil'.  If the item is unselectable, it will
     usually be displayed grayed-out to indicate this.

:suffix FORM
     FORM will be evaluated when the menu that this item is a part of
     is about to be displayed, and the resulting string is appended to
     the displayed name.  This provides a convenient way of adding the
     name of a command's "argument" to the menu, like `Kill Buffer
     NAME'.

:keys STRING
     Normally, the keyboard equivalents of commands in menus are
     displayed when the "callback" is a symbol.  This can be used to
     specify keys for more complex menu items.  It is passed through
     `substitute-command-keys' first.

:style STYLE
     Specifies what kind of object this menu item is.  STYLE be one of
     the symbols

    `nil'
          A normal menu item.

    `toggle'
          A toggle button.

    `radio'
          A radio button.

    `button'
          A menubar button.

     The only difference between toggle and radio buttons is how they
     are displayed.  But for consistency, a toggle button should be
     used when there is one option whose value can be turned on or off,
     and radio buttons should be used when there is a set of mutually
     exclusive options.  When using a group of radio buttons, you
     should arrange for no more than one to be marked as selected at a
     time.

:selected FORM
     Meaningful only when STYLE is `toggle', `radio' or `button'.  This
     specifies whether the button will be in the selected or unselected
     state.  FORM is evaluated, as for `:active'.

:included FORM
     This can be used to control the visibility of a menu item.  The
     form is evaluated and the menu item is only displayed if the
     result is non-`nil'.  Note that this is different from `:active':
     If `:active' evaluates to `nil', the item will be displayed grayed
     out, while if `:included' evaluates to `nil', the item will be
     omitted entirely.

:config SYMBOL
     This is an efficient shorthand for `:included (memq SYMBOL
     menubar-configuration)'.  See the variable `menubar-configuration'.

:accelerator KEY
     A menu accelerator is a keystroke which can be pressed while the
     menu is visible which will immediately activate the item.  KEY
     must be a char or the symbol name of a key.  *Note Menu
     Accelerators::.

 - Variable: menubar-configuration
     This variable holds a list of symbols, against which the value of
     the `:config' tag for each menubar item will be compared.  If a
     menubar item has a `:config' tag, then it is omitted from the
     menubar if that tag is not a member of the `menubar-configuration'
     list.

   For example:

      ("File"
       :filter file-menu-filter ; file-menu-filter is a function that takes
                                ; one argument (a list of menu items) and
                                ; returns a list of menu items
       [ "Save As..."    write-file]
       [ "Revert Buffer" revert-buffer :active (buffer-modified-p) ]
       [ "Read Only"     toggle-read-only :style toggle :selected buffer-read-only ]
       )

\1f
File: lispref.info,  Node: Menubar Format,  Next: Menubar,  Prev: Menu Format,  Up: Menus

Format of the Menubar
=====================

   A menubar is a list of menus, menu items, and strings.  The format is
similar to that of a menu, except:

   * The first item need not be a string, and is not treated specially.

   * A string consisting solely of hyphens is not treated specially.

   * If an element of a menubar is `nil', then it is used to represent
     the division between the set of menubar items which are flush-left
     and those which are flush-right.  (Note: this isn't completely
     implemented yet.)

\1f
File: lispref.info,  Node: Menubar,  Next: Modifying Menus,  Prev: Menubar Format,  Up: Menus

Menubar
=======

 - Variable: current-menubar
     This variable holds the description of the current menubar.  This
     may be buffer-local.  When the menubar is changed, the function
     `set-menubar-dirty-flag' has to be called in order for the menubar
     to be updated on the screen.

 - Constant: default-menubar
     This variable holds the menubar description of the menubar that is
     visible at startup.  This is the value that `current-menubar' has
     at startup.

 - Function: set-menubar-dirty-flag
     This function tells XEmacs that the menubar widget has to be
     updated.  Changes to the menubar will generally not be visible
     until this function is called.

   The following convenience functions are provided for setting the
menubar.  They are equivalent to doing the appropriate action to change
`current-menubar', and then calling `set-menubar-dirty-flag'.  Note
that these functions copy their argument using `copy-sequence'.

 - Function: set-menubar MENUBAR
     This function sets the default menubar to be MENUBAR (*note Menu
     Format::.).  This is the menubar that will be visible in buffers
     that have not defined their own, buffer-local menubar.

 - Function: set-buffer-menubar MENUBAR
     This function sets the buffer-local menubar to be MENUBAR.  This
     does not change the menubar in any buffers other than the current
     one.

   Miscellaneous:

 - Variable: menubar-show-keybindings
     If true, the menubar will display keyboard equivalents.  If false,
     only the command names will be displayed.

 - Variable: activate-menubar-hook
     Function or functions called before a menubar menu is pulled down.
     These functions are called with no arguments, and should
     interrogate and modify the value of `current-menubar' as desired.

     The functions on this hook are invoked after the mouse goes down,
     but before the menu is mapped, and may be used to activate,
     deactivate, add, or delete items from the menus.  However, using a
     filter (with the `:filter' keyword in a menu description) is
     generally a more efficient way of accomplishing the same thing,
     because the filter is invoked only when the actual menu goes down.
     With a complex menu, there can be a quite noticeable and
     sometimes aggravating delay if all menu modification is
     implemented using the `activate-menubar-hook'.  See above.

     These functions may return the symbol `t' to assert that they have
     made no changes to the menubar.  If any other value is returned,
     the menubar is recomputed.  If `t' is returned but the menubar has
     been changed, then the changes may not show up right away.
     Returning `nil' when the menubar has not changed is not so bad;
     more computation will be done, but redisplay of the menubar will
     still be performed optimally.

 - Variable: menu-no-selection-hook
     Function or functions to call when a menu or dialog box is
     dismissed without a selection having been made.

\1f
File: lispref.info,  Node: Modifying Menus,  Next: Pop-Up Menus,  Prev: Menubar,  Up: Menus

Modifying Menus
===============

   The following functions are provided to modify the menubar of one of
its submenus.  Note that these functions modify the menu in-place,
rather than copying it and making a new menu.

   Some of these functions take a "menu path", which is a list of
strings identifying the menu to be modified.  For example, `("File")'
names the top-level "File" menu.  `("File" "Foo")' names a hypothetical
submenu of "File".

   Others take a "menu item path", which is similar to a menu path but
also specifies a particular item to be modified.  For example, `("File"
"Save")' means the menu item called "Save" under the top-level "File"
menu.  `("Menu" "Foo" "Item")' means the menu item called "Item" under
the "Foo" submenu of "Menu".

 - Function: add-submenu MENU-PATH SUBMENU &optional BEFORE
     This function adds a menu to the menubar or one of its submenus.
     If the named menu exists already, it is changed.

     MENU-PATH identifies the menu under which the new menu should be
     inserted.  If MENU-PATH is `nil', then the menu will be added to
     the menubar itself.

     SUBMENU is the new menu to add (*note Menu Format::.).

     BEFORE, if provided, is the name of a menu before which this menu
     should be added, if this menu is not on its parent already.  If
     the menu is already present, it will not be moved.

 - Function: add-menu-button MENU-PATH MENU-LEAF &optional BEFORE
     This function adds a menu item to some menu, creating the menu
     first if necessary.  If the named item exists already, it is
     changed.

     MENU-PATH identifies the menu under which the new menu item should
     be inserted.

     MENU-LEAF is a menubar leaf node (*note Menu Format::.).

     BEFORE, if provided, is the name of a menu before which this item
     should be added, if this item is not on the menu already.  If the
     item is already present, it will not be moved.

 - Function: delete-menu-item MENU-ITEM-PATH
     This function removes the menu item specified by MENU-ITEM-PATH
     from the menu hierarchy.

 - Function: enable-menu-item MENU-ITEM-PATH
     This function makes the menu item specified by MENU-ITEM-PATH be
     selectable.

 - Function: disable-menu-item MENU-ITEM-PATH
     This function makes the menu item specified by MENU-ITEM-PATH be
     unselectable.

 - Function: relabel-menu-item MENU-ITEM-PATH NEW-NAME
     This function changes the string of the menu item specified by
     MENU-ITEM-PATH.  NEW-NAME is the string that the menu item will be
     printed as from now on.

   The following function can be used to search for a particular item in
a menubar specification, given a path to the item.

 - Function: find-menu-item MENUBAR MENU-ITEM-PATH &optional PARENT
     This function searches MENUBAR for the item given by
     MENU-ITEM-PATH starting from PARENT (`nil' means start at the top
     of MENUBAR).  This function returns `(ITEM . PARENT)', where
     PARENT is the immediate parent of the item found (a menu
     description), and ITEM is either a vector, list, or string,
     depending on the nature of the menu item.

     This function signals an error if the item is not found.

   The following deprecated functions are also documented, so that
existing code can be understood.  You should not use these functions in
new code.

 - Function: add-menu MENU-PATH MENU-NAME MENU-ITEMS &optional BEFORE
     This function adds a menu to the menubar or one of its submenus.
     If the named menu exists already, it is changed.  This is
     obsolete; use `add-submenu' instead.

     MENU-PATH identifies the menu under which the new menu should be
     inserted.  If MENU-PATH is `nil', then the menu will be added to
     the menubar itself.

     MENU-NAME is the string naming the menu to be added; MENU-ITEMS is
     a list of menu items, strings, and submenus.  These two arguments
     are the same as the first and following elements of a menu
     description (*note Menu Format::.).

     BEFORE, if provided, is the name of a menu before which this menu
     should be added, if this menu is not on its parent already.  If the
     menu is already present, it will not be moved.

 - Function: add-menu-item MENU-PATH ITEM-NAME FUNCTION ENABLED-P
          &optional BEFORE
     This function adds a menu item to some menu, creating the menu
     first if necessary.  If the named item exists already, it is
     changed.  This is obsolete; use `add-menu-button' instead.

     MENU-PATH identifies the menu under which the new menu item should
     be inserted. ITEM-NAME, FUNCTION, and ENABLED-P are the first,
     second, and third elements of a menu item vector (*note Menu
     Format::.).

     BEFORE, if provided, is the name of a menu item before which this
     item should be added, if this item is not on the menu already.  If
     the item is already present, it will not be moved.

\1f
File: lispref.info,  Node: Menu Filters,  Next: Menu Accelerators,  Prev: Pop-Up Menus,  Up: Menus

Menu Filters
============

   The following filter functions are provided for use in
`default-menubar'.  You may want to use them in your own menubar
description.

 - Function: file-menu-filter MENU-ITEMS
     This function changes the arguments and sensitivity of these File
     menu items:

    `Delete Buffer'
          Has the name of the current buffer appended to it.

    `Print Buffer'
          Has the name of the current buffer appended to it.

    `Pretty-Print Buffer'
          Has the name of the current buffer appended to it.

    `Save Buffer'
          Has the name of the current buffer appended to it, and is
          sensitive only when the current buffer is modified.

    `Revert Buffer'
          Has the name of the current buffer appended to it, and is
          sensitive only when the current buffer has a file.

    `Delete Frame'
          Sensitive only when there is more than one visible frame.

 - Function: edit-menu-filter MENU-ITEMS
     This function changes the arguments and sensitivity of these Edit
     menu items:

    `Cut'
          Sensitive only when XEmacs owns the primary X Selection (if
          `zmacs-regions' is `t', this is equivalent to saying that
          there is a region selected).

    `Copy'
          Sensitive only when XEmacs owns the primary X Selection.

    `Clear'
          Sensitive only when XEmacs owns the primary X Selection.

    `Paste'
          Sensitive only when there is an owner for the X Clipboard
          Selection.

    `Undo'
          Sensitive only when there is undo information.  While in the
          midst of an undo, this is changed to `Undo More'.

 - Function: buffers-menu-filter MENU-ITEMS
     This function sets up the Buffers menu.  *Note Buffers Menu::, for
     more information.