2 @c This is part of the GNU Emacs Lisp Reference Manual.
3 @c Copyright (C) 1990-1994, 1998-2012 Free Software Foundation, Inc.
4 @c See the file elisp.texi for copying conditions.
5 @node Keymaps, Modes, Command Loop, Top
9 The command bindings of input events are recorded in data structures
10 called @dfn{keymaps}. Each entry in a keymap associates (or
11 @dfn{binds}) an individual event type, either to another keymap or to
12 a command. When an event type is bound to a keymap, that keymap is
13 used to look up the next input event; this continues until a command
14 is found. The whole process is called @dfn{key lookup}.
17 * Key Sequences:: Key sequences as Lisp objects.
18 * Keymap Basics:: Basic concepts of keymaps.
19 * Format of Keymaps:: What a keymap looks like as a Lisp object.
20 * Creating Keymaps:: Functions to create and copy keymaps.
21 * Inheritance and Keymaps:: How one keymap can inherit the bindings
23 * Prefix Keys:: Defining a key with a keymap as its definition.
24 * Active Keymaps:: How Emacs searches the active keymaps
26 * Searching Keymaps:: A pseudo-Lisp summary of searching active maps.
27 * Controlling Active Maps:: Each buffer has a local keymap
28 to override the standard (global) bindings.
29 A minor mode can also override them.
30 * Key Lookup:: Finding a key's binding in one keymap.
31 * Functions for Key Lookup:: How to request key lookup.
32 * Changing Key Bindings:: Redefining a key in a keymap.
33 * Remapping Commands:: A keymap can translate one command to another.
34 * Translation Keymaps:: Keymaps for translating sequences of events.
35 * Key Binding Commands:: Interactive interfaces for redefining keys.
36 * Scanning Keymaps:: Looking through all keymaps, for printing help.
37 * Menu Keymaps:: Defining a menu as a keymap.
41 @section Key Sequences
46 A @dfn{key sequence}, or @dfn{key} for short, is a sequence of one
47 or more input events that form a unit. Input events include
48 characters, function keys, and mouse actions (@pxref{Input Events}).
49 The Emacs Lisp representation for a key sequence is a string or
50 vector. Unless otherwise stated, any Emacs Lisp function that accepts
51 a key sequence as an argument can handle both representations.
53 In the string representation, alphanumeric characters ordinarily
54 stand for themselves; for example, @code{"a"} represents @kbd{a}
55 and @code{"2"} represents @kbd{2}. Control character events are
56 prefixed by the substring @code{"\C-"}, and meta characters by
57 @code{"\M-"}; for example, @code{"\C-x"} represents the key @kbd{C-x}.
58 In addition, the @key{TAB}, @key{RET}, @key{ESC}, and @key{DEL} events
59 are represented by @code{"\t"}, @code{"\r"}, @code{"\e"}, and
60 @code{"\d"} respectively. The string representation of a complete key
61 sequence is the concatenation of the string representations of the
62 constituent events; thus, @code{"\C-xl"} represents the key sequence
65 Key sequences containing function keys, mouse button events, or
66 non-@acronym{ASCII} characters such as @kbd{C-=} or @kbd{H-a} cannot be
67 represented as strings; they have to be represented as vectors.
69 In the vector representation, each element of the vector represents
70 an input event, in its Lisp form. @xref{Input Events}. For example,
71 the vector @code{[?\C-x ?l]} represents the key sequence @kbd{C-x l}.
73 For examples of key sequences written in string and vector
74 representations, @ref{Init Rebinding,,, emacs, The GNU Emacs Manual}.
76 @defmac kbd keyseq-text
77 This macro converts the text @var{keyseq-text} (a string constant)
78 into a key sequence (a string or vector constant). The contents of
79 @var{keyseq-text} should describe the key sequence using almost the same
80 syntax used in this manual. More precisely, it uses the same syntax
81 that Edit Macro mode uses for editing keyboard macros (@pxref{Edit
82 Keyboard Macro,,, emacs, The GNU Emacs Manual}); you must surround
83 function key names with @samp{<@dots{}>}.
86 (kbd "C-x") @result{} "\C-x"
87 (kbd "C-x C-f") @result{} "\C-x\C-f"
88 (kbd "C-x 4 C-f") @result{} "\C-x4\C-f"
89 (kbd "X") @result{} "X"
90 (kbd "RET") @result{} "\^M"
91 (kbd "C-c SPC") @result{} "\C-c@ "
92 (kbd "<f1> SPC") @result{} [f1 32]
93 (kbd "C-M-<down>") @result{} [C-M-down]
96 This macro is not meant for use with arguments that vary---only
97 with string constants.
101 @section Keymap Basics
103 @cindex binding of a key
105 @cindex undefined key
107 A keymap is a Lisp data structure that specifies @dfn{key bindings}
108 for various key sequences.
110 A single keymap directly specifies definitions for individual
111 events. When a key sequence consists of a single event, its binding
112 in a keymap is the keymap's definition for that event. The binding of
113 a longer key sequence is found by an iterative process: first find the
114 definition of the first event (which must itself be a keymap); then
115 find the second event's definition in that keymap, and so on until all
116 the events in the key sequence have been processed.
118 If the binding of a key sequence is a keymap, we call the key sequence
119 a @dfn{prefix key}. Otherwise, we call it a @dfn{complete key} (because
120 no more events can be added to it). If the binding is @code{nil},
121 we call the key @dfn{undefined}. Examples of prefix keys are @kbd{C-c},
122 @kbd{C-x}, and @kbd{C-x 4}. Examples of defined complete keys are
123 @kbd{X}, @key{RET}, and @kbd{C-x 4 C-f}. Examples of undefined complete
124 keys are @kbd{C-x C-g}, and @kbd{C-c 3}. @xref{Prefix Keys}, for more
127 The rule for finding the binding of a key sequence assumes that the
128 intermediate bindings (found for the events before the last) are all
129 keymaps; if this is not so, the sequence of events does not form a
130 unit---it is not really one key sequence. In other words, removing one
131 or more events from the end of any valid key sequence must always yield
132 a prefix key. For example, @kbd{C-f C-n} is not a key sequence;
133 @kbd{C-f} is not a prefix key, so a longer sequence starting with
134 @kbd{C-f} cannot be a key sequence.
136 The set of possible multi-event key sequences depends on the bindings
137 for prefix keys; therefore, it can be different for different keymaps,
138 and can change when bindings are changed. However, a one-event sequence
139 is always a key sequence, because it does not depend on any prefix keys
140 for its well-formedness.
142 At any time, several primary keymaps are @dfn{active}---that is, in
143 use for finding key bindings. These are the @dfn{global map}, which is
144 shared by all buffers; the @dfn{local keymap}, which is usually
145 associated with a specific major mode; and zero or more @dfn{minor mode
146 keymaps}, which belong to currently enabled minor modes. (Not all minor
147 modes have keymaps.) The local keymap bindings shadow (i.e., take
148 precedence over) the corresponding global bindings. The minor mode
149 keymaps shadow both local and global keymaps. @xref{Active Keymaps},
152 @node Format of Keymaps
153 @section Format of Keymaps
154 @cindex format of keymaps
155 @cindex keymap format
157 @cindex sparse keymap
159 Each keymap is a list whose @sc{car} is the symbol @code{keymap}. The
160 remaining elements of the list define the key bindings of the keymap.
161 A symbol whose function definition is a keymap is also a keymap. Use
162 the function @code{keymapp} (see below) to test whether an object is a
165 Several kinds of elements may appear in a keymap, after the symbol
166 @code{keymap} that begins it:
169 @item (@var{type} .@: @var{binding})
170 This specifies one binding, for events of type @var{type}. Each
171 ordinary binding applies to events of a particular @dfn{event type},
172 which is always a character or a symbol. @xref{Classifying Events}.
173 In this kind of binding, @var{binding} is a command.
175 @item (@var{type} @var{item-name} .@: @var{binding})
176 This specifies a binding which is also a simple menu item that
177 displays as @var{item-name} in the menu. @xref{Simple Menu Items}.
179 @item (@var{type} @var{item-name} @var{help-string} .@: @var{binding})
180 This is a simple menu item with help string @var{help-string}.
182 @item (@var{type} menu-item .@: @var{details})
183 This specifies a binding which is also an extended menu item. This
184 allows use of other features. @xref{Extended Menu Items}.
186 @item (t .@: @var{binding})
187 @cindex default key binding
188 This specifies a @dfn{default key binding}; any event not bound by other
189 elements of the keymap is given @var{binding} as its binding. Default
190 bindings allow a keymap to bind all possible event types without having
191 to enumerate all of them. A keymap that has a default binding
192 completely masks any lower-precedence keymap, except for events
193 explicitly bound to @code{nil} (see below).
195 @item @var{char-table}
196 If an element of a keymap is a char-table, it counts as holding
197 bindings for all character events with no modifier bits
198 (@pxref{modifier bits}): element @var{n} is the binding for the
199 character with code @var{n}. This is a compact way to record lots of
200 bindings. A keymap with such a char-table is called a @dfn{full
201 keymap}. Other keymaps are called @dfn{sparse keymaps}.
204 @cindex keymap prompt string
205 @cindex overall prompt string
206 @cindex prompt string of keymap
207 Aside from elements that specify bindings for keys, a keymap can also
208 have a string as an element. This is called the @dfn{overall prompt
209 string} and makes it possible to use the keymap as a menu.
210 @xref{Defining Menus}.
213 When the binding is @code{nil}, it doesn't constitute a definition
214 but it does take precedence over a default binding or a binding in the
215 parent keymap. On the other hand, a binding of @code{nil} does
216 @emph{not} override lower-precedence keymaps; thus, if the local map
217 gives a binding of @code{nil}, Emacs uses the binding from the
220 @cindex meta characters lookup
221 Keymaps do not directly record bindings for the meta characters.
222 Instead, meta characters are regarded for purposes of key lookup as
223 sequences of two characters, the first of which is @key{ESC} (or
224 whatever is currently the value of @code{meta-prefix-char}). Thus, the
225 key @kbd{M-a} is internally represented as @kbd{@key{ESC} a}, and its
226 global binding is found at the slot for @kbd{a} in @code{esc-map}
227 (@pxref{Prefix Keys}).
229 This conversion applies only to characters, not to function keys or
230 other input events; thus, @kbd{M-@key{end}} has nothing to do with
231 @kbd{@key{ESC} @key{end}}.
233 Here as an example is the local keymap for Lisp mode, a sparse
234 keymap. It defines bindings for @key{DEL}, @kbd{C-c C-z},
235 @kbd{C-M-q}, and @kbd{C-M-x} (the actual value also contains a menu
236 binding, which is omitted here for the sake of brevity).
251 ;; @r{@kbd{C-M-x}, treated as @kbd{@key{ESC} C-x}}
252 (24 . lisp-send-defun))
255 ;; @r{This part is inherited from @code{lisp-mode-shared-map}.}
258 (127 . backward-delete-char-untabify)
262 ;; @r{@kbd{C-M-q}, treated as @kbd{@key{ESC} C-q}}
267 @defun keymapp object
268 This function returns @code{t} if @var{object} is a keymap, @code{nil}
269 otherwise. More precisely, this function tests for a list whose
270 @sc{car} is @code{keymap}, or for a symbol whose function definition
271 satisfies @code{keymapp}.
279 (fset 'foo '(keymap))
284 (keymapp (current-global-map))
290 @node Creating Keymaps
291 @section Creating Keymaps
292 @cindex creating keymaps
294 Here we describe the functions for creating keymaps.
296 @defun make-sparse-keymap &optional prompt
297 This function creates and returns a new sparse keymap with no entries.
298 (A sparse keymap is the kind of keymap you usually want.) The new
299 keymap does not contain a char-table, unlike @code{make-keymap}, and
300 does not bind any events.
309 If you specify @var{prompt}, that becomes the overall prompt string
310 for the keymap. You should specify this only for menu keymaps
311 (@pxref{Defining Menus}). A keymap with an overall prompt string will
312 always present a mouse menu or a keyboard menu if it is active for
313 looking up the next input event. Don't specify an overall prompt string
314 for the main map of a major or minor mode, because that would cause
315 the command loop to present a keyboard menu every time.
318 @defun make-keymap &optional prompt
319 This function creates and returns a new full keymap. That keymap
320 contains a char-table (@pxref{Char-Tables}) with slots for all
321 characters without modifiers. The new keymap initially binds all
322 these characters to @code{nil}, and does not bind any other kind of
323 event. The argument @var{prompt} specifies a
324 prompt string, as in @code{make-sparse-keymap}.
329 @result{} (keymap #^[t nil nil nil @dots{} nil nil keymap])
333 A full keymap is more efficient than a sparse keymap when it holds
334 lots of bindings; for just a few, the sparse keymap is better.
337 @defun copy-keymap keymap
338 This function returns a copy of @var{keymap}. Any keymaps that
339 appear directly as bindings in @var{keymap} are also copied recursively,
340 and so on to any number of levels. However, recursive copying does not
341 take place when the definition of a character is a symbol whose function
342 definition is a keymap; the same symbol appears in the new copy.
347 (setq map (copy-keymap (current-local-map)))
351 ;; @r{(This implements meta characters.)}
353 (83 . center-paragraph)
355 (9 . tab-to-tab-stop))
359 (eq map (current-local-map))
363 (equal map (current-local-map))
369 @node Inheritance and Keymaps
370 @section Inheritance and Keymaps
371 @cindex keymap inheritance
372 @cindex inheriting a keymap's bindings
374 A keymap can inherit the bindings of another keymap, which we call the
375 @dfn{parent keymap}. Such a keymap looks like this:
378 (keymap @var{elements}@dots{} . @var{parent-keymap})
382 The effect is that this keymap inherits all the bindings of
383 @var{parent-keymap}, whatever they may be at the time a key is looked up,
384 but can add to them or override them with @var{elements}.
386 If you change the bindings in @var{parent-keymap} using
387 @code{define-key} or other key-binding functions, these changed
388 bindings are visible in the inheriting keymap, unless shadowed by the
389 bindings made by @var{elements}. The converse is not true: if you use
390 @code{define-key} to change bindings in the inheriting keymap, these
391 changes are recorded in @var{elements}, but have no effect on
394 The proper way to construct a keymap with a parent is to use
395 @code{set-keymap-parent}; if you have code that directly constructs a
396 keymap with a parent, please convert the program to use
397 @code{set-keymap-parent} instead.
399 @defun keymap-parent keymap
400 This returns the parent keymap of @var{keymap}. If @var{keymap}
401 has no parent, @code{keymap-parent} returns @code{nil}.
404 @defun set-keymap-parent keymap parent
405 This sets the parent keymap of @var{keymap} to @var{parent}, and returns
406 @var{parent}. If @var{parent} is @code{nil}, this function gives
407 @var{keymap} no parent at all.
409 If @var{keymap} has submaps (bindings for prefix keys), they too receive
410 new parent keymaps that reflect what @var{parent} specifies for those
414 Here is an example showing how to make a keymap that inherits
415 from @code{text-mode-map}:
418 (let ((map (make-sparse-keymap)))
419 (set-keymap-parent map text-mode-map)
423 A non-sparse keymap can have a parent too, but this is not very
424 useful. A non-sparse keymap always specifies something as the binding
425 for every numeric character code without modifier bits, even if it is
426 @code{nil}, so these character's bindings are never inherited from
429 @cindex keymap inheritance from multiple maps
430 Sometimes you want to make a keymap that inherits from more than one
431 map. You can use the function @code{make-composed-keymap} for this.
433 @defun make-composed-keymap maps &optional parent
434 This function returns a new keymap composed of the existing keymap(s)
435 @var{maps}, and optionally inheriting from a parent keymap
436 @var{parent}. @var{maps} can be a single keymap or a list of more
437 than one. When looking up a key in the resulting new map, Emacs
438 searches in each of the @var{maps} in turn, and then in @var{parent},
439 stopping at the first match. A @code{nil} binding in any one of
440 @var{maps} overrides any binding in @var{parent}, but it does not
441 override any non-@code{nil} binding in any other of the @var{maps}.
444 @noindent For example, here is how Emacs sets the parent of
445 @code{help-mode-map}, such that it inherits from both
446 @code{button-buffer-map} and @code{special-mode-map}:
449 (defvar help-mode-map
450 (let ((map (make-sparse-keymap)))
451 (set-keymap-parent map (make-composed-keymap button-buffer-map
461 A @dfn{prefix key} is a key sequence whose binding is a keymap. The
462 keymap defines what to do with key sequences that extend the prefix key.
463 For example, @kbd{C-x} is a prefix key, and it uses a keymap that is
464 also stored in the variable @code{ctl-x-map}. This keymap defines
465 bindings for key sequences starting with @kbd{C-x}.
467 Some of the standard Emacs prefix keys use keymaps that are
468 also found in Lisp variables:
474 @code{esc-map} is the global keymap for the @key{ESC} prefix key. Thus,
475 the global definitions of all meta characters are actually found here.
476 This map is also the function definition of @code{ESC-prefix}.
480 @code{help-map} is the global keymap for the @kbd{C-h} prefix key.
484 @vindex mode-specific-map
485 @code{mode-specific-map} is the global keymap for the prefix key
486 @kbd{C-c}. This map is actually global, not mode-specific, but its name
487 provides useful information about @kbd{C-c} in the output of @kbd{C-h b}
488 (@code{display-bindings}), since the main use of this prefix key is for
489 mode-specific bindings.
494 @findex Control-X-prefix
495 @code{ctl-x-map} is the global keymap used for the @kbd{C-x} prefix key.
496 This map is found via the function cell of the symbol
497 @code{Control-X-prefix}.
500 @cindex @kbd{C-x @key{RET}}
502 @code{mule-keymap} is the global keymap used for the @kbd{C-x @key{RET}}
508 @code{ctl-x-4-map} is the global keymap used for the @kbd{C-x 4} prefix
514 @code{ctl-x-5-map} is the global keymap used for the @kbd{C-x 5} prefix
520 @code{2C-mode-map} is the global keymap used for the @kbd{C-x 6} prefix
525 @vindex vc-prefix-map
526 @code{vc-prefix-map} is the global keymap used for the @kbd{C-x v} prefix
532 @code{goto-map} is the global keymap used for the @kbd{M-g} prefix
538 @code{search-map} is the global keymap used for the @kbd{M-s} prefix
543 @vindex facemenu-keymap
544 @code{facemenu-keymap} is the global keymap used for the @kbd{M-o}
548 The other Emacs prefix keys are @kbd{C-x @@}, @kbd{C-x a i}, @kbd{C-x
549 @key{ESC}} and @kbd{@key{ESC} @key{ESC}}. They use keymaps that have
553 The keymap binding of a prefix key is used for looking up the event
554 that follows the prefix key. (It may instead be a symbol whose function
555 definition is a keymap. The effect is the same, but the symbol serves
556 as a name for the prefix key.) Thus, the binding of @kbd{C-x} is the
557 symbol @code{Control-X-prefix}, whose function cell holds the keymap
558 for @kbd{C-x} commands. (The same keymap is also the value of
561 Prefix key definitions can appear in any active keymap. The
562 definitions of @kbd{C-c}, @kbd{C-x}, @kbd{C-h} and @key{ESC} as prefix
563 keys appear in the global map, so these prefix keys are always
564 available. Major and minor modes can redefine a key as a prefix by
565 putting a prefix key definition for it in the local map or the minor
566 mode's map. @xref{Active Keymaps}.
568 If a key is defined as a prefix in more than one active map, then its
569 various definitions are in effect merged: the commands defined in the
570 minor mode keymaps come first, followed by those in the local map's
571 prefix definition, and then by those from the global map.
573 In the following example, we make @kbd{C-p} a prefix key in the local
574 keymap, in such a way that @kbd{C-p} is identical to @kbd{C-x}. Then
575 the binding for @kbd{C-p C-f} is the function @code{find-file}, just
576 like @kbd{C-x C-f}. The key sequence @kbd{C-p 6} is not found in any
581 (use-local-map (make-sparse-keymap))
585 (local-set-key "\C-p" ctl-x-map)
589 (key-binding "\C-p\C-f")
594 (key-binding "\C-p6")
599 @defun define-prefix-command symbol &optional mapvar prompt
600 @cindex prefix command
601 @anchor{Definition of define-prefix-command}
602 This function prepares @var{symbol} for use as a prefix key's binding:
603 it creates a sparse keymap and stores it as @var{symbol}'s function
604 definition. Subsequently binding a key sequence to @var{symbol} will
605 make that key sequence into a prefix key. The return value is @code{symbol}.
607 This function also sets @var{symbol} as a variable, with the keymap as
608 its value. But if @var{mapvar} is non-@code{nil}, it sets @var{mapvar}
609 as a variable instead.
611 If @var{prompt} is non-@code{nil}, that becomes the overall prompt
612 string for the keymap. The prompt string should be given for menu keymaps
613 (@pxref{Defining Menus}).
617 @section Active Keymaps
618 @cindex active keymap
619 @cindex global keymap
622 Emacs normally contains many keymaps; at any given time, just a few
623 of them are @dfn{active}, meaning that they participate in the
624 interpretation of user input. All the active keymaps are used
625 together to determine what command to execute when a key is entered.
627 Normally the active keymaps are the @code{keymap} property keymap,
628 the keymaps of any enabled minor modes, the current buffer's local
629 keymap, and the global keymap, in that order. Emacs searches for each
630 input key sequence in all these keymaps. @xref{Searching Keymaps},
631 for more details of this procedure.
633 When the key sequence starts with a mouse event (optionally preceded
634 by a symbolic prefix), the active keymaps are determined based on the
635 position in that event. If the event happened on a string embedded
636 with a @code{display}, @code{before-string}, or @code{after-string}
637 property (@pxref{Special Properties}), the non-@code{nil} map
638 properties of the string override those of the buffer (if the
639 underlying buffer text contains map properties in its text properties
640 or overlays, they are ignored).
642 The @dfn{global keymap} holds the bindings of keys that are defined
643 regardless of the current buffer, such as @kbd{C-f}. The variable
644 @code{global-map} holds this keymap, which is always active.
646 Each buffer may have another keymap, its @dfn{local keymap}, which
647 may contain new or overriding definitions for keys. The current
648 buffer's local keymap is always active except when
649 @code{overriding-local-map} overrides it. The @code{local-map} text
650 or overlay property can specify an alternative local keymap for certain
651 parts of the buffer; see @ref{Special Properties}.
653 Each minor mode can have a keymap; if it does, the keymap is active
654 when the minor mode is enabled. Modes for emulation can specify
655 additional active keymaps through the variable
656 @code{emulation-mode-map-alists}.
658 The highest precedence normal keymap comes from the @code{keymap}
659 text or overlay property. If that is non-@code{nil}, it is the first
660 keymap to be processed, in normal circumstances.
662 However, there are also special ways for programs to substitute
663 other keymaps for some of those. The variable
664 @code{overriding-local-map}, if non-@code{nil}, specifies a keymap
665 that replaces all the usual active keymaps except the global keymap.
666 Another way to do this is with @code{overriding-terminal-local-map};
667 it operates on a per-terminal basis. These variables are documented
670 @cindex major mode keymap
671 Since every buffer that uses the same major mode normally uses the
672 same local keymap, you can think of the keymap as local to the mode. A
673 change to the local keymap of a buffer (using @code{local-set-key}, for
674 example) is seen also in the other buffers that share that keymap.
676 The local keymaps that are used for Lisp mode and some other major
677 modes exist even if they have not yet been used. These local keymaps are
678 the values of variables such as @code{lisp-mode-map}. For most major
679 modes, which are less frequently used, the local keymap is constructed
680 only when the mode is used for the first time in a session.
682 The minibuffer has local keymaps, too; they contain various completion
683 and exit commands. @xref{Intro to Minibuffers}.
685 Emacs has other keymaps that are used in a different way---translating
686 events within @code{read-key-sequence}. @xref{Translation Keymaps}.
688 @xref{Standard Keymaps}, for a list of some standard keymaps.
690 @defun current-active-maps &optional olp position
691 This returns the list of active keymaps that would be used by the
692 command loop in the current circumstances to look up a key sequence.
693 Normally it ignores @code{overriding-local-map} and
694 @code{overriding-terminal-local-map}, but if @var{olp} is non-@code{nil}
695 then it pays attention to them. @var{position} can optionally be either
696 an event position as returned by @code{event-start} or a buffer
697 position, and may change the keymaps as described for
701 @defun key-binding key &optional accept-defaults no-remap position
702 This function returns the binding for @var{key} according to the
703 current active keymaps. The result is @code{nil} if @var{key} is
704 undefined in the keymaps.
706 The argument @var{accept-defaults} controls checking for default
707 bindings, as in @code{lookup-key} (@pxref{Functions for Key Lookup}).
709 When commands are remapped (@pxref{Remapping Commands}),
710 @code{key-binding} normally processes command remappings so as to
711 return the remapped command that will actually be executed. However,
712 if @var{no-remap} is non-@code{nil}, @code{key-binding} ignores
713 remappings and returns the binding directly specified for @var{key}.
715 If @var{key} starts with a mouse event (perhaps following a prefix
716 event), the maps to be consulted are determined based on the event's
717 position. Otherwise, they are determined based on the value of point.
718 However, you can override either of them by specifying @var{position}.
719 If @var{position} is non-@code{nil}, it should be either a buffer
720 position or an event position like the value of @code{event-start}.
721 Then the maps consulted are determined based on @var{position}.
723 An error is signaled if @var{key} is not a string or a vector.
727 (key-binding "\C-x\C-f")
733 @node Searching Keymaps
734 @section Searching the Active Keymaps
735 @cindex searching active keymaps for keys
737 After translation of event subsequences (@pxref{Translation
738 Keymaps}) Emacs looks for them in the active keymaps. Here is a
739 pseudo-Lisp description of the order and conditions for searching
744 (overriding-terminal-local-map
745 (@var{find-in} overriding-terminal-local-map))
746 (overriding-local-map
747 (@var{find-in} overriding-local-map))
748 ((or (@var{find-in} (get-char-property (point) 'keymap))
749 (@var{find-in-any} emulation-mode-map-alists)
750 (@var{find-in-any} minor-mode-overriding-map-alist)
751 (@var{find-in-any} minor-mode-map-alist)
752 (if (get-text-property (point) 'local-map)
753 (@var{find-in} (get-char-property (point) 'local-map))
754 (@var{find-in} (current-local-map))))))
755 (@var{find-in} (current-global-map)))
759 @var{find-in} and @var{find-in-any} are pseudo functions that search
760 in one keymap and in an alist of keymaps, respectively. (Searching a
761 single keymap for a binding is called @dfn{key lookup}; see @ref{Key
762 Lookup}.) If the key sequence starts with a mouse event, or a
763 symbolic prefix event followed by a mouse event, that event's position
764 is used instead of point and the current buffer. Mouse events on an
765 embedded string use non-@code{nil} text properties from that string
766 instead of the buffer.
768 When a match is found (@pxref{Key Lookup}), if the binding in the
769 keymap is a function, the search is over. However if the keymap entry
770 is a symbol with a value or a string, Emacs replaces the input key
771 sequences with the variable's value or the string, and restarts the
772 search of the active keymaps.
774 The function finally found might also be remapped. @xref{Remapping
777 @node Controlling Active Maps
778 @section Controlling the Active Keymaps
781 This variable contains the default global keymap that maps Emacs
782 keyboard input to commands. The global keymap is normally this
783 keymap. The default global keymap is a full keymap that binds
784 @code{self-insert-command} to all of the printing characters.
786 It is normal practice to change the bindings in the global keymap, but you
787 should not assign this variable any value other than the keymap it starts
791 @defun current-global-map
792 This function returns the current global keymap. This is the same as
793 the value of @code{global-map} unless you change one or the other.
794 The return value is a reference, not a copy; if you use
795 @code{define-key} or other functions on it you will alter global
801 @result{} (keymap [set-mark-command beginning-of-line @dots{}
802 delete-backward-char])
807 @defun current-local-map
808 This function returns the current buffer's local keymap, or @code{nil}
809 if it has none. In the following example, the keymap for the
810 @file{*scratch*} buffer (using Lisp Interaction mode) is a sparse keymap
811 in which the entry for @key{ESC}, @acronym{ASCII} code 27, is another sparse
818 (10 . eval-print-last-sexp)
819 (9 . lisp-indent-line)
820 (127 . backward-delete-char-untabify)
830 @code{current-local-map} returns a reference to the local keymap, not
831 a copy of it; if you use @code{define-key} or other functions on it
832 you will alter local bindings.
834 @defun current-minor-mode-maps
835 This function returns a list of the keymaps of currently enabled minor modes.
838 @defun use-global-map keymap
839 This function makes @var{keymap} the new current global keymap. It
842 It is very unusual to change the global keymap.
845 @defun use-local-map keymap
846 This function makes @var{keymap} the new local keymap of the current
847 buffer. If @var{keymap} is @code{nil}, then the buffer has no local
848 keymap. @code{use-local-map} returns @code{nil}. Most major mode
849 commands use this function.
853 @defvar minor-mode-map-alist
854 @anchor{Definition of minor-mode-map-alist}
855 This variable is an alist describing keymaps that may or may not be
856 active according to the values of certain variables. Its elements look
860 (@var{variable} . @var{keymap})
863 The keymap @var{keymap} is active whenever @var{variable} has a
864 non-@code{nil} value. Typically @var{variable} is the variable that
865 enables or disables a minor mode. @xref{Keymaps and Minor Modes}.
867 Note that elements of @code{minor-mode-map-alist} do not have the same
868 structure as elements of @code{minor-mode-alist}. The map must be the
869 @sc{cdr} of the element; a list with the map as the second element will
870 not do. The @sc{cdr} can be either a keymap (a list) or a symbol whose
871 function definition is a keymap.
873 When more than one minor mode keymap is active, the earlier one in
874 @code{minor-mode-map-alist} takes priority. But you should design
875 minor modes so that they don't interfere with each other. If you do
876 this properly, the order will not matter.
878 See @ref{Keymaps and Minor Modes}, for more information about minor
879 modes. See also @code{minor-mode-key-binding} (@pxref{Functions for Key
883 @defvar minor-mode-overriding-map-alist
884 This variable allows major modes to override the key bindings for
885 particular minor modes. The elements of this alist look like the
886 elements of @code{minor-mode-map-alist}: @code{(@var{variable}
889 If a variable appears as an element of
890 @code{minor-mode-overriding-map-alist}, the map specified by that
891 element totally replaces any map specified for the same variable in
892 @code{minor-mode-map-alist}.
894 @code{minor-mode-overriding-map-alist} is automatically buffer-local in
898 @defvar overriding-local-map
899 If non-@code{nil}, this variable holds a keymap to use instead of the
900 buffer's local keymap, any text property or overlay keymaps, and any
901 minor mode keymaps. This keymap, if specified, overrides all other
902 maps that would have been active, except for the current global map.
905 @defvar overriding-terminal-local-map
906 If non-@code{nil}, this variable holds a keymap to use instead of
907 @code{overriding-local-map}, the buffer's local keymap, text property
908 or overlay keymaps, and all the minor mode keymaps.
910 This variable is always local to the current terminal and cannot be
911 buffer-local. @xref{Multiple Terminals}. It is used to implement
912 incremental search mode.
915 @defvar overriding-local-map-menu-flag
916 If this variable is non-@code{nil}, the value of
917 @code{overriding-local-map} or @code{overriding-terminal-local-map} can
918 affect the display of the menu bar. The default value is @code{nil}, so
919 those map variables have no effect on the menu bar.
921 Note that these two map variables do affect the execution of key
922 sequences entered using the menu bar, even if they do not affect the
923 menu bar display. So if a menu bar key sequence comes in, you should
924 clear the variables before looking up and executing that key sequence.
925 Modes that use the variables would typically do this anyway; normally
926 they respond to events that they do not handle by ``unreading'' them and
930 @defvar special-event-map
931 This variable holds a keymap for special events. If an event type has a
932 binding in this keymap, then it is special, and the binding for the
933 event is run directly by @code{read-event}. @xref{Special Events}.
936 @defvar emulation-mode-map-alists
937 This variable holds a list of keymap alists to use for emulations
938 modes. It is intended for modes or packages using multiple minor-mode
939 keymaps. Each element is a keymap alist which has the same format and
940 meaning as @code{minor-mode-map-alist}, or a symbol with a variable
941 binding which is such an alist. The ``active'' keymaps in each alist
942 are used before @code{minor-mode-map-alist} and
943 @code{minor-mode-overriding-map-alist}.
951 @dfn{Key lookup} is the process of finding the binding of a key
952 sequence from a given keymap. The execution or use of the binding is
953 not part of key lookup.
955 Key lookup uses just the event type of each event in the key sequence;
956 the rest of the event is ignored. In fact, a key sequence used for key
957 lookup may designate a mouse event with just its types (a symbol)
958 instead of the entire event (a list). @xref{Input Events}. Such
959 a ``key sequence'' is insufficient for @code{command-execute} to run,
960 but it is sufficient for looking up or rebinding a key.
962 When the key sequence consists of multiple events, key lookup
963 processes the events sequentially: the binding of the first event is
964 found, and must be a keymap; then the second event's binding is found in
965 that keymap, and so on until all the events in the key sequence are used
966 up. (The binding thus found for the last event may or may not be a
967 keymap.) Thus, the process of key lookup is defined in terms of a
968 simpler process for looking up a single event in a keymap. How that is
969 done depends on the type of object associated with the event in that
972 Let's use the term @dfn{keymap entry} to describe the value found by
973 looking up an event type in a keymap. (This doesn't include the item
974 string and other extra elements in a keymap element for a menu item, because
975 @code{lookup-key} and other key lookup functions don't include them in
976 the returned value.) While any Lisp object may be stored in a keymap
977 as a keymap entry, not all make sense for key lookup. Here is a table
978 of the meaningful types of keymap entries:
982 @cindex @code{nil} in keymap
983 @code{nil} means that the events used so far in the lookup form an
984 undefined key. When a keymap fails to mention an event type at all, and
985 has no default binding, that is equivalent to a binding of @code{nil}
989 @cindex command in keymap
990 The events used so far in the lookup form a complete key,
991 and @var{command} is its binding. @xref{What Is a Function}.
994 @cindex string in keymap
995 The array (either a string or a vector) is a keyboard macro. The events
996 used so far in the lookup form a complete key, and the array is its
997 binding. See @ref{Keyboard Macros}, for more information.
1000 @cindex keymap in keymap
1001 The events used so far in the lookup form a prefix key. The next
1002 event of the key sequence is looked up in @var{keymap}.
1005 @cindex list in keymap
1006 The meaning of a list depends on what it contains:
1010 If the @sc{car} of @var{list} is the symbol @code{keymap}, then the list
1011 is a keymap, and is treated as a keymap (see above).
1014 @cindex @code{lambda} in keymap
1015 If the @sc{car} of @var{list} is @code{lambda}, then the list is a
1016 lambda expression. This is presumed to be a function, and is treated
1017 as such (see above). In order to execute properly as a key binding,
1018 this function must be a command---it must have an @code{interactive}
1019 specification. @xref{Defining Commands}.
1022 If the @sc{car} of @var{list} is a keymap and the @sc{cdr} is an event
1023 type, then this is an @dfn{indirect entry}:
1026 (@var{othermap} . @var{othertype})
1029 When key lookup encounters an indirect entry, it looks up instead the
1030 binding of @var{othertype} in @var{othermap} and uses that.
1032 This feature permits you to define one key as an alias for another key.
1033 For example, an entry whose @sc{car} is the keymap called @code{esc-map}
1034 and whose @sc{cdr} is 32 (the code for @key{SPC}) means, ``Use the global
1035 binding of @kbd{Meta-@key{SPC}}, whatever that may be''.
1039 @cindex symbol in keymap
1040 The function definition of @var{symbol} is used in place of
1041 @var{symbol}. If that too is a symbol, then this process is repeated,
1042 any number of times. Ultimately this should lead to an object that is
1043 a keymap, a command, or a keyboard macro. A list is allowed if it is a
1044 keymap or a command, but indirect entries are not understood when found
1047 Note that keymaps and keyboard macros (strings and vectors) are not
1048 valid functions, so a symbol with a keymap, string, or vector as its
1049 function definition is invalid as a function. It is, however, valid as
1050 a key binding. If the definition is a keyboard macro, then the symbol
1051 is also valid as an argument to @code{command-execute}
1052 (@pxref{Interactive Call}).
1054 @cindex @code{undefined} in keymap
1055 The symbol @code{undefined} is worth special mention: it means to treat
1056 the key as undefined. Strictly speaking, the key is defined, and its
1057 binding is the command @code{undefined}; but that command does the same
1058 thing that is done automatically for an undefined key: it rings the bell
1059 (by calling @code{ding}) but does not signal an error.
1061 @cindex preventing prefix key
1062 @code{undefined} is used in local keymaps to override a global key
1063 binding and make the key ``undefined'' locally. A local binding of
1064 @code{nil} would fail to do this because it would not override the
1067 @item @var{anything else}
1068 If any other type of object is found, the events used so far in the
1069 lookup form a complete key, and the object is its binding, but the
1070 binding is not executable as a command.
1073 In short, a keymap entry may be a keymap, a command, a keyboard
1074 macro, a symbol that leads to one of them, or an indirection or
1077 @node Functions for Key Lookup
1078 @section Functions for Key Lookup
1080 Here are the functions and variables pertaining to key lookup.
1082 @defun lookup-key keymap key &optional accept-defaults
1083 This function returns the definition of @var{key} in @var{keymap}. All
1084 the other functions described in this chapter that look up keys use
1085 @code{lookup-key}. Here are examples:
1089 (lookup-key (current-global-map) "\C-x\C-f")
1093 (lookup-key (current-global-map) (kbd "C-x C-f"))
1097 (lookup-key (current-global-map) "\C-x\C-f12345")
1102 If the string or vector @var{key} is not a valid key sequence according
1103 to the prefix keys specified in @var{keymap}, it must be ``too long''
1104 and have extra events at the end that do not fit into a single key
1105 sequence. Then the value is a number, the number of events at the front
1106 of @var{key} that compose a complete key.
1109 If @var{accept-defaults} is non-@code{nil}, then @code{lookup-key}
1110 considers default bindings as well as bindings for the specific events
1111 in @var{key}. Otherwise, @code{lookup-key} reports only bindings for
1112 the specific sequence @var{key}, ignoring default bindings except when
1113 you explicitly ask about them. (To do this, supply @code{t} as an
1114 element of @var{key}; see @ref{Format of Keymaps}.)
1116 If @var{key} contains a meta character (not a function key), that
1117 character is implicitly replaced by a two-character sequence: the value
1118 of @code{meta-prefix-char}, followed by the corresponding non-meta
1119 character. Thus, the first example below is handled by conversion into
1124 (lookup-key (current-global-map) "\M-f")
1125 @result{} forward-word
1128 (lookup-key (current-global-map) "\ef")
1129 @result{} forward-word
1133 Unlike @code{read-key-sequence}, this function does not modify the
1134 specified events in ways that discard information (@pxref{Key Sequence
1135 Input}). In particular, it does not convert letters to lower case and
1136 it does not change drag events to clicks.
1139 @deffn Command undefined
1140 Used in keymaps to undefine keys. It calls @code{ding}, but does
1144 @defun local-key-binding key &optional accept-defaults
1145 This function returns the binding for @var{key} in the current
1146 local keymap, or @code{nil} if it is undefined there.
1149 The argument @var{accept-defaults} controls checking for default bindings,
1150 as in @code{lookup-key} (above).
1153 @defun global-key-binding key &optional accept-defaults
1154 This function returns the binding for command @var{key} in the
1155 current global keymap, or @code{nil} if it is undefined there.
1158 The argument @var{accept-defaults} controls checking for default bindings,
1159 as in @code{lookup-key} (above).
1163 @defun minor-mode-key-binding key &optional accept-defaults
1164 This function returns a list of all the active minor mode bindings of
1165 @var{key}. More precisely, it returns an alist of pairs
1166 @code{(@var{modename} . @var{binding})}, where @var{modename} is the
1167 variable that enables the minor mode, and @var{binding} is @var{key}'s
1168 binding in that mode. If @var{key} has no minor-mode bindings, the
1169 value is @code{nil}.
1171 If the first binding found is not a prefix definition (a keymap or a
1172 symbol defined as a keymap), all subsequent bindings from other minor
1173 modes are omitted, since they would be completely shadowed. Similarly,
1174 the list omits non-prefix bindings that follow prefix bindings.
1176 The argument @var{accept-defaults} controls checking for default
1177 bindings, as in @code{lookup-key} (above).
1180 @defopt meta-prefix-char
1182 This variable is the meta-prefix character code. It is used for
1183 translating a meta character to a two-character sequence so it can be
1184 looked up in a keymap. For useful results, the value should be a
1185 prefix event (@pxref{Prefix Keys}). The default value is 27, which is
1186 the @acronym{ASCII} code for @key{ESC}.
1188 As long as the value of @code{meta-prefix-char} remains 27, key lookup
1189 translates @kbd{M-b} into @kbd{@key{ESC} b}, which is normally defined
1190 as the @code{backward-word} command. However, if you were to set
1191 @code{meta-prefix-char} to 24, the code for @kbd{C-x}, then Emacs will
1192 translate @kbd{M-b} into @kbd{C-x b}, whose standard binding is the
1193 @code{switch-to-buffer} command. (Don't actually do this!) Here is an
1194 illustration of what would happen:
1198 meta-prefix-char ; @r{The default value.}
1202 (key-binding "\M-b")
1203 @result{} backward-word
1206 ?\C-x ; @r{The print representation}
1207 @result{} 24 ; @r{of a character.}
1210 (setq meta-prefix-char 24)
1214 (key-binding "\M-b")
1215 @result{} switch-to-buffer ; @r{Now, typing @kbd{M-b} is}
1216 ; @r{like typing @kbd{C-x b}.}
1218 (setq meta-prefix-char 27) ; @r{Avoid confusion!}
1219 @result{} 27 ; @r{Restore the default value!}
1223 This translation of one event into two happens only for characters, not
1224 for other kinds of input events. Thus, @kbd{M-@key{F1}}, a function
1225 key, is not converted into @kbd{@key{ESC} @key{F1}}.
1228 @node Changing Key Bindings
1229 @section Changing Key Bindings
1230 @cindex changing key bindings
1233 The way to rebind a key is to change its entry in a keymap. If you
1234 change a binding in the global keymap, the change is effective in all
1235 buffers (though it has no direct effect in buffers that shadow the
1236 global binding with a local one). If you change the current buffer's
1237 local map, that usually affects all buffers using the same major mode.
1238 The @code{global-set-key} and @code{local-set-key} functions are
1239 convenient interfaces for these operations (@pxref{Key Binding
1240 Commands}). You can also use @code{define-key}, a more general
1241 function; then you must explicitly specify the map to change.
1243 When choosing the key sequences for Lisp programs to rebind, please
1244 follow the Emacs conventions for use of various keys (@pxref{Key
1245 Binding Conventions}).
1247 @cindex meta character key constants
1248 @cindex control character key constants
1249 In writing the key sequence to rebind, it is good to use the special
1250 escape sequences for control and meta characters (@pxref{String Type}).
1251 The syntax @samp{\C-} means that the following character is a control
1252 character and @samp{\M-} means that the following character is a meta
1253 character. Thus, the string @code{"\M-x"} is read as containing a
1254 single @kbd{M-x}, @code{"\C-f"} is read as containing a single
1255 @kbd{C-f}, and @code{"\M-\C-x"} and @code{"\C-\M-x"} are both read as
1256 containing a single @kbd{C-M-x}. You can also use this escape syntax in
1257 vectors, as well as others that aren't allowed in strings; one example
1258 is @samp{[?\C-\H-x home]}. @xref{Character Type}.
1260 The key definition and lookup functions accept an alternate syntax for
1261 event types in a key sequence that is a vector: you can use a list
1262 containing modifier names plus one base event (a character or function
1263 key name). For example, @code{(control ?a)} is equivalent to
1264 @code{?\C-a} and @code{(hyper control left)} is equivalent to
1265 @code{C-H-left}. One advantage of such lists is that the precise
1266 numeric codes for the modifier bits don't appear in compiled files.
1268 The functions below signal an error if @var{keymap} is not a keymap,
1269 or if @var{key} is not a string or vector representing a key sequence.
1270 You can use event types (symbols) as shorthand for events that are
1271 lists. The @code{kbd} macro (@pxref{Key Sequences}) is a convenient
1272 way to specify the key sequence.
1274 @defun define-key keymap key binding
1275 This function sets the binding for @var{key} in @var{keymap}. (If
1276 @var{key} is more than one event long, the change is actually made
1277 in another keymap reached from @var{keymap}.) The argument
1278 @var{binding} can be any Lisp object, but only certain types are
1279 meaningful. (For a list of meaningful types, see @ref{Key Lookup}.)
1280 The value returned by @code{define-key} is @var{binding}.
1282 If @var{key} is @code{[t]}, this sets the default binding in
1283 @var{keymap}. When an event has no binding of its own, the Emacs
1284 command loop uses the keymap's default binding, if there is one.
1286 @cindex invalid prefix key error
1287 @cindex key sequence error
1288 Every prefix of @var{key} must be a prefix key (i.e., bound to a keymap)
1289 or undefined; otherwise an error is signaled. If some prefix of
1290 @var{key} is undefined, then @code{define-key} defines it as a prefix
1291 key so that the rest of @var{key} can be defined as specified.
1293 If there was previously no binding for @var{key} in @var{keymap}, the
1294 new binding is added at the beginning of @var{keymap}. The order of
1295 bindings in a keymap makes no difference for keyboard input, but it
1296 does matter for menu keymaps (@pxref{Menu Keymaps}).
1299 This example creates a sparse keymap and makes a number of
1304 (setq map (make-sparse-keymap))
1308 (define-key map "\C-f" 'forward-char)
1309 @result{} forward-char
1313 @result{} (keymap (6 . forward-char))
1317 ;; @r{Build sparse submap for @kbd{C-x} and bind @kbd{f} in that.}
1318 (define-key map (kbd "C-x f") 'forward-word)
1319 @result{} forward-word
1324 (24 keymap ; @kbd{C-x}
1325 (102 . forward-word)) ; @kbd{f}
1326 (6 . forward-char)) ; @kbd{C-f}
1330 ;; @r{Bind @kbd{C-p} to the @code{ctl-x-map}.}
1331 (define-key map (kbd "C-p") ctl-x-map)
1333 @result{} [nil @dots{} find-file @dots{} backward-kill-sentence]
1337 ;; @r{Bind @kbd{C-f} to @code{foo} in the @code{ctl-x-map}.}
1338 (define-key map (kbd "C-p C-f") 'foo)
1343 @result{} (keymap ; @r{Note @code{foo} in @code{ctl-x-map}.}
1344 (16 keymap [nil @dots{} foo @dots{} backward-kill-sentence])
1346 (102 . forward-word))
1352 Note that storing a new binding for @kbd{C-p C-f} actually works by
1353 changing an entry in @code{ctl-x-map}, and this has the effect of
1354 changing the bindings of both @kbd{C-p C-f} and @kbd{C-x C-f} in the
1357 The function @code{substitute-key-definition} scans a keymap for
1358 keys that have a certain binding and rebinds them with a different
1359 binding. Another feature which is cleaner and can often produce the
1360 same results to remap one command into another (@pxref{Remapping
1363 @defun substitute-key-definition olddef newdef keymap &optional oldmap
1364 @cindex replace bindings
1365 This function replaces @var{olddef} with @var{newdef} for any keys in
1366 @var{keymap} that were bound to @var{olddef}. In other words,
1367 @var{olddef} is replaced with @var{newdef} wherever it appears. The
1368 function returns @code{nil}.
1370 For example, this redefines @kbd{C-x C-f}, if you do it in an Emacs with
1375 (substitute-key-definition
1376 'find-file 'find-file-read-only (current-global-map))
1381 If @var{oldmap} is non-@code{nil}, that changes the behavior of
1382 @code{substitute-key-definition}: the bindings in @var{oldmap} determine
1383 which keys to rebind. The rebindings still happen in @var{keymap}, not
1384 in @var{oldmap}. Thus, you can change one map under the control of the
1385 bindings in another. For example,
1388 (substitute-key-definition
1389 'delete-backward-char 'my-funny-delete
1394 puts the special deletion command in @code{my-map} for whichever keys
1395 are globally bound to the standard deletion command.
1397 Here is an example showing a keymap before and after substitution:
1405 @result{} (keymap (49 . olddef-1) (50 . olddef-2) (51 . olddef-1))
1409 (substitute-key-definition 'olddef-1 'newdef map)
1414 @result{} (keymap (49 . newdef) (50 . olddef-2) (51 . newdef))
1419 @defun suppress-keymap keymap &optional nodigits
1420 @cindex @code{self-insert-command} override
1421 This function changes the contents of the full keymap @var{keymap} by
1422 remapping @code{self-insert-command} to the command @code{undefined}
1423 (@pxref{Remapping Commands}). This has the effect of undefining all
1424 printing characters, thus making ordinary insertion of text impossible.
1425 @code{suppress-keymap} returns @code{nil}.
1427 If @var{nodigits} is @code{nil}, then @code{suppress-keymap} defines
1428 digits to run @code{digit-argument}, and @kbd{-} to run
1429 @code{negative-argument}. Otherwise it makes them undefined like the
1430 rest of the printing characters.
1432 @cindex yank suppression
1433 @cindex @code{quoted-insert} suppression
1434 The @code{suppress-keymap} function does not make it impossible to
1435 modify a buffer, as it does not suppress commands such as @code{yank}
1436 and @code{quoted-insert}. To prevent any modification of a buffer, make
1437 it read-only (@pxref{Read Only Buffers}).
1439 Since this function modifies @var{keymap}, you would normally use it
1440 on a newly created keymap. Operating on an existing keymap
1441 that is used for some other purpose is likely to cause trouble; for
1442 example, suppressing @code{global-map} would make it impossible to use
1445 This function can be used to initialize the local keymap of a major
1446 mode for which insertion of text is not desirable. But usually such a
1447 mode should be derived from @code{special-mode} (@pxref{Basic Major
1448 Modes}); then its keymap will automatically inherit from
1449 @code{special-mode-map}, which is already suppressed. Here is how
1450 @code{special-mode-map} is defined:
1454 (defvar special-mode-map
1455 (let ((map (make-sparse-keymap)))
1456 (suppress-keymap map)
1457 (define-key map "q" 'quit-window)
1464 @node Remapping Commands
1465 @section Remapping Commands
1466 @cindex remapping commands
1468 A special kind of key binding can be used to @dfn{remap} one command
1469 to another, without having to refer to the key sequence(s) bound to
1470 the original command. To use this feature, make a key binding for a
1471 key sequence that starts with the dummy event @code{remap}, followed
1472 by the command name you want to remap; for the binding, specify the
1473 new definition (usually a command name, but possibly any other valid
1474 definition for a key binding).
1476 For example, suppose My mode provides a special command
1477 @code{my-kill-line}, which should be invoked instead of
1478 @code{kill-line}. To establish this, its mode keymap should contain
1479 the following remapping:
1482 (define-key my-mode-map [remap kill-line] 'my-kill-line)
1486 Then, whenever @code{my-mode-map} is active, if the user types
1487 @kbd{C-k} (the default global key sequence for @code{kill-line}) Emacs
1488 will instead run @code{my-kill-line}.
1490 Note that remapping only takes place through active keymaps; for
1491 example, putting a remapping in a prefix keymap like @code{ctl-x-map}
1492 typically has no effect, as such keymaps are not themselves active.
1493 In addition, remapping only works through a single level; in the
1497 (define-key my-mode-map [remap kill-line] 'my-kill-line)
1498 (define-key my-mode-map [remap my-kill-line] 'my-other-kill-line)
1502 @code{kill-line} is @emph{not} remapped to @code{my-other-kill-line}.
1503 Instead, if an ordinary key binding specifies @code{kill-line}, it is
1504 remapped to @code{my-kill-line}; if an ordinary binding specifies
1505 @code{my-kill-line}, it is remapped to @code{my-other-kill-line}.
1507 To undo the remapping of a command, remap it to @code{nil}; e.g.
1510 (define-key my-mode-map [remap kill-line] nil)
1513 @defun command-remapping command &optional position keymaps
1514 This function returns the remapping for @var{command} (a symbol),
1515 given the current active keymaps. If @var{command} is not remapped
1516 (which is the usual situation), or not a symbol, the function returns
1517 @code{nil}. @code{position} can optionally specify a buffer position
1518 or an event position to determine the keymaps to use, as in
1521 If the optional argument @code{keymaps} is non-@code{nil}, it
1522 specifies a list of keymaps to search in. This argument is ignored if
1523 @code{position} is non-@code{nil}.
1526 @node Translation Keymaps
1527 @section Keymaps for Translating Sequences of Events
1528 @cindex keymaps for translating events
1530 This section describes keymaps that are used during reading a key
1531 sequence, to translate certain event sequences into others.
1532 @code{read-key-sequence} checks every subsequence of the key sequence
1533 being read, as it is read, against @code{input-decode-map}, then
1534 @code{local-function-key-map}, and then against @code{key-translation-map}.
1536 @defvar input-decode-map
1537 This variable holds a keymap that describes the character sequences sent
1538 by function keys on an ordinary character terminal. This keymap has the
1539 same structure as other keymaps, but is used differently: it specifies
1540 translations to make while reading key sequences, rather than bindings
1543 If @code{input-decode-map} ``binds'' a key sequence @var{k} to a vector
1544 @var{v}, then when @var{k} appears as a subsequence @emph{anywhere} in a
1545 key sequence, it is replaced with the events in @var{v}.
1547 For example, VT100 terminals send @kbd{@key{ESC} O P} when the
1548 keypad @key{PF1} key is pressed. Therefore, we want Emacs to translate
1549 that sequence of events into the single event @code{pf1}. We accomplish
1550 this by ``binding'' @kbd{@key{ESC} O P} to @code{[pf1]} in
1551 @code{input-decode-map}, when using a VT100.
1553 Thus, typing @kbd{C-c @key{PF1}} sends the character sequence @kbd{C-c
1554 @key{ESC} O P}; later the function @code{read-key-sequence} translates
1555 this back into @kbd{C-c @key{PF1}}, which it returns as the vector
1558 The value of @code{input-decode-map} is usually set up automatically
1559 according to the terminal's Terminfo or Termcap entry, but sometimes
1560 those need help from terminal-specific Lisp files. Emacs comes with
1561 terminal-specific files for many common terminals; their main purpose is
1562 to make entries in @code{input-decode-map} beyond those that can be
1563 deduced from Termcap and Terminfo. @xref{Terminal-Specific}.
1566 @defvar local-function-key-map
1567 This variable holds a keymap similar to @code{input-decode-map} except
1568 that it describes key sequences which should be translated to
1569 alternative interpretations that are usually preferred. It applies
1570 after @code{input-decode-map} and before @code{key-translation-map}.
1572 Entries in @code{local-function-key-map} are ignored if they conflict
1573 with bindings made in the minor mode, local, or global keymaps. I.e.
1574 the remapping only applies if the original key sequence would
1575 otherwise not have any binding.
1577 @code{local-function-key-map} inherits from @code{function-key-map},
1578 but the latter should not be used directly.
1581 @defvar key-translation-map
1582 This variable is another keymap used just like @code{input-decode-map}
1583 to translate input events into other events. It differs from
1584 @code{input-decode-map} in that it goes to work after
1585 @code{local-function-key-map} is finished rather than before; it
1586 receives the results of translation by @code{local-function-key-map}.
1588 Just like @code{input-decode-map}, but unlike
1589 @code{local-function-key-map}, this keymap is applied regardless of
1590 whether the input key-sequence has a normal binding. Note however
1591 that actual key bindings can have an effect on
1592 @code{key-translation-map}, even though they are overridden by it.
1593 Indeed, actual key bindings override @code{local-function-key-map} and
1594 thus may alter the key sequence that @code{key-translation-map}
1595 receives. Clearly, it is better to avoid this type of situation.
1597 The intent of @code{key-translation-map} is for users to map one
1598 character set to another, including ordinary characters normally bound
1599 to @code{self-insert-command}.
1602 @cindex key translation function
1603 You can use @code{input-decode-map}, @code{local-function-key-map}, or
1604 @code{key-translation-map} for more than simple aliases, by using a
1605 function, instead of a key sequence, as the ``translation'' of a key.
1606 Then this function is called to compute the translation of that key.
1608 The key translation function receives one argument, which is the prompt
1609 that was specified in @code{read-key-sequence}---or @code{nil} if the
1610 key sequence is being read by the editor command loop. In most cases
1611 you can ignore the prompt value.
1613 If the function reads input itself, it can have the effect of altering
1614 the event that follows. For example, here's how to define @kbd{C-c h}
1615 to turn the character that follows into a Hyper character:
1619 (defun hyperify (prompt)
1620 (let ((e (read-event)))
1621 (vector (if (numberp e)
1622 (logior (lsh 1 24) e)
1623 (if (memq 'hyper (event-modifiers e))
1625 (add-event-modifier "H-" e))))))
1627 (defun add-event-modifier (string e)
1628 (let ((symbol (if (symbolp e) e (car e))))
1629 (setq symbol (intern (concat string
1630 (symbol-name symbol))))
1635 (cons symbol (cdr e)))))
1637 (define-key local-function-key-map "\C-ch" 'hyperify)
1641 If you have enabled keyboard character set decoding using
1642 @code{set-keyboard-coding-system}, decoding is done after the
1643 translations listed above. @xref{Terminal I/O Encoding}. However, in
1644 future Emacs versions, character set decoding may be done at an
1647 @node Key Binding Commands
1648 @section Commands for Binding Keys
1650 This section describes some convenient interactive interfaces for
1651 changing key bindings. They work by calling @code{define-key}.
1653 People often use @code{global-set-key} in their init files
1654 (@pxref{Init File}) for simple customization. For example,
1657 (global-set-key (kbd "C-x C-\\") 'next-line)
1664 (global-set-key [?\C-x ?\C-\\] 'next-line)
1671 (global-set-key [(control ?x) (control ?\\)] 'next-line)
1675 redefines @kbd{C-x C-\} to move down a line.
1678 (global-set-key [M-mouse-1] 'mouse-set-point)
1682 redefines the first (leftmost) mouse button, entered with the Meta key, to
1683 set point where you click.
1685 @cindex non-@acronym{ASCII} text in keybindings
1686 Be careful when using non-@acronym{ASCII} text characters in Lisp
1687 specifications of keys to bind. If these are read as multibyte text, as
1688 they usually will be in a Lisp file (@pxref{Loading Non-ASCII}), you
1689 must type the keys as multibyte too. For instance, if you use this:
1692 (global-set-key "@"o" 'my-function) ; bind o-umlaut
1699 (global-set-key ?@"o 'my-function) ; bind o-umlaut
1703 and your language environment is multibyte Latin-1, these commands
1704 actually bind the multibyte character with code 246, not the byte
1705 code 246 (@kbd{M-v}) sent by a Latin-1 terminal. In order to use this
1706 binding, you need to teach Emacs how to decode the keyboard by using an
1707 appropriate input method (@pxref{Input Methods, , Input Methods, emacs, The GNU
1710 @deffn Command global-set-key key binding
1711 This function sets the binding of @var{key} in the current global map
1716 (global-set-key @var{key} @var{binding})
1718 (define-key (current-global-map) @var{key} @var{binding})
1723 @deffn Command global-unset-key key
1724 @cindex unbinding keys
1725 This function removes the binding of @var{key} from the current
1728 One use of this function is in preparation for defining a longer key
1729 that uses @var{key} as a prefix---which would not be allowed if
1730 @var{key} has a non-prefix binding. For example:
1734 (global-unset-key "\C-l")
1738 (global-set-key "\C-l\C-l" 'redraw-display)
1743 This function is implemented simply using @code{define-key}:
1747 (global-unset-key @var{key})
1749 (define-key (current-global-map) @var{key} nil)
1754 @deffn Command local-set-key key binding
1755 This function sets the binding of @var{key} in the current local
1756 keymap to @var{binding}.
1760 (local-set-key @var{key} @var{binding})
1762 (define-key (current-local-map) @var{key} @var{binding})
1767 @deffn Command local-unset-key key
1768 This function removes the binding of @var{key} from the current
1773 (local-unset-key @var{key})
1775 (define-key (current-local-map) @var{key} nil)
1780 @node Scanning Keymaps
1781 @section Scanning Keymaps
1783 This section describes functions used to scan all the current keymaps
1784 for the sake of printing help information.
1786 @defun accessible-keymaps keymap &optional prefix
1787 This function returns a list of all the keymaps that can be reached (via
1788 zero or more prefix keys) from @var{keymap}. The value is an
1789 association list with elements of the form @code{(@var{key} .@:
1790 @var{map})}, where @var{key} is a prefix key whose definition in
1791 @var{keymap} is @var{map}.
1793 The elements of the alist are ordered so that the @var{key} increases
1794 in length. The first element is always @code{([] .@: @var{keymap})},
1795 because the specified keymap is accessible from itself with a prefix of
1798 If @var{prefix} is given, it should be a prefix key sequence; then
1799 @code{accessible-keymaps} includes only the submaps whose prefixes start
1800 with @var{prefix}. These elements look just as they do in the value of
1801 @code{(accessible-keymaps)}; the only difference is that some elements
1804 In the example below, the returned alist indicates that the key
1805 @key{ESC}, which is displayed as @samp{^[}, is a prefix key whose
1806 definition is the sparse keymap @code{(keymap (83 .@: center-paragraph)
1811 (accessible-keymaps (current-local-map))
1812 @result{}(([] keymap
1813 (27 keymap ; @r{Note this keymap for @key{ESC} is repeated below.}
1814 (83 . center-paragraph)
1815 (115 . center-line))
1816 (9 . tab-to-tab-stop))
1821 (83 . center-paragraph)
1826 In the following example, @kbd{C-h} is a prefix key that uses a sparse
1827 keymap starting with @code{(keymap (118 . describe-variable)@dots{})}.
1828 Another prefix, @kbd{C-x 4}, uses a keymap which is also the value of
1829 the variable @code{ctl-x-4-map}. The event @code{mode-line} is one of
1830 several dummy events used as prefixes for mouse actions in special parts
1835 (accessible-keymaps (current-global-map))
1836 @result{} (([] keymap [set-mark-command beginning-of-line @dots{}
1837 delete-backward-char])
1840 ("^H" keymap (118 . describe-variable) @dots{}
1841 (8 . help-for-help))
1844 ("^X" keymap [x-flush-mouse-queue @dots{}
1845 backward-kill-sentence])
1848 ("^[" keymap [mark-sexp backward-sexp @dots{}
1849 backward-kill-word])
1851 ("^X4" keymap (15 . display-buffer) @dots{})
1854 (S-mouse-2 . mouse-split-window-horizontally) @dots{}))
1859 These are not all the keymaps you would see in actuality.
1862 @defun map-keymap function keymap
1863 The function @code{map-keymap} calls @var{function} once
1864 for each binding in @var{keymap}. It passes two arguments,
1865 the event type and the value of the binding. If @var{keymap}
1866 has a parent, the parent's bindings are included as well.
1867 This works recursively: if the parent has itself a parent, then the
1868 grandparent's bindings are also included and so on.
1870 This function is the cleanest way to examine all the bindings
1874 @defun where-is-internal command &optional keymap firstonly noindirect no-remap
1875 This function is a subroutine used by the @code{where-is} command
1876 (@pxref{Help, , Help, emacs,The GNU Emacs Manual}). It returns a list
1877 of all key sequences (of any length) that are bound to @var{command} in a
1880 The argument @var{command} can be any object; it is compared with all
1881 keymap entries using @code{eq}.
1883 If @var{keymap} is @code{nil}, then the maps used are the current active
1884 keymaps, disregarding @code{overriding-local-map} (that is, pretending
1885 its value is @code{nil}). If @var{keymap} is a keymap, then the
1886 maps searched are @var{keymap} and the global keymap. If @var{keymap}
1887 is a list of keymaps, only those keymaps are searched.
1889 Usually it's best to use @code{overriding-local-map} as the expression
1890 for @var{keymap}. Then @code{where-is-internal} searches precisely
1891 the keymaps that are active. To search only the global map, pass the
1892 value @code{(keymap)} (an empty keymap) as @var{keymap}.
1894 If @var{firstonly} is @code{non-ascii}, then the value is a single
1895 vector representing the first key sequence found, rather than a list of
1896 all possible key sequences. If @var{firstonly} is @code{t}, then the
1897 value is the first key sequence, except that key sequences consisting
1898 entirely of @acronym{ASCII} characters (or meta variants of @acronym{ASCII}
1899 characters) are preferred to all other key sequences and that the
1900 return value can never be a menu binding.
1902 If @var{noindirect} is non-@code{nil}, @code{where-is-internal} doesn't
1903 follow indirect keymap bindings. This makes it possible to search for
1904 an indirect definition itself.
1906 The fifth argument, @var{no-remap}, determines how this function
1907 treats command remappings (@pxref{Remapping Commands}). There are two
1911 @item If a command @var{other-command} is remapped to @var{command}:
1912 If @var{no-remap} is @code{nil}, find the bindings for
1913 @var{other-command} and treat them as though they are also bindings
1914 for @var{command}. If @var{no-remap} is non-@code{nil}, include the
1915 vector @code{[remap @var{other-command}]} in the list of possible key
1916 sequences, instead of finding those bindings.
1918 @item If @var{command} is remapped to @var{other-command}:
1919 If @var{no-remap} is @code{nil}, return the bindings for
1920 @var{other-command} rather than @var{command}. If @var{no-remap} is
1921 non-@code{nil}, return the bindings for @var{command}, ignoring the
1922 fact that it is remapped.
1926 @deffn Command describe-bindings &optional prefix buffer-or-name
1927 This function creates a listing of all current key bindings, and
1928 displays it in a buffer named @file{*Help*}. The text is grouped by
1929 modes---minor modes first, then the major mode, then global bindings.
1931 If @var{prefix} is non-@code{nil}, it should be a prefix key; then the
1932 listing includes only keys that start with @var{prefix}.
1934 The listing describes meta characters as @key{ESC} followed by the
1935 corresponding non-meta character.
1937 When several characters with consecutive @acronym{ASCII} codes have the
1938 same definition, they are shown together, as
1939 @samp{@var{firstchar}..@var{lastchar}}. In this instance, you need to
1940 know the @acronym{ASCII} codes to understand which characters this means.
1941 For example, in the default global map, the characters @samp{@key{SPC}
1942 ..@: ~} are described by a single line. @key{SPC} is @acronym{ASCII} 32,
1943 @kbd{~} is @acronym{ASCII} 126, and the characters between them include all
1944 the normal printing characters, (e.g., letters, digits, punctuation,
1945 etc.@:); all these characters are bound to @code{self-insert-command}.
1947 If @var{buffer-or-name} is non-@code{nil}, it should be a buffer or a
1948 buffer name. Then @code{describe-bindings} lists that buffer's bindings,
1949 instead of the current buffer's.
1953 @section Menu Keymaps
1954 @cindex menu keymaps
1956 A keymap can operate as a menu as well as defining bindings for
1957 keyboard keys and mouse buttons. Menus are usually actuated with the
1958 mouse, but they can function with the keyboard also. If a menu keymap
1959 is active for the next input event, that activates the keyboard menu
1963 * Defining Menus:: How to make a keymap that defines a menu.
1964 * Mouse Menus:: How users actuate the menu with the mouse.
1965 * Keyboard Menus:: How users actuate the menu with the keyboard.
1966 * Menu Example:: Making a simple menu.
1967 * Menu Bar:: How to customize the menu bar.
1968 * Tool Bar:: A tool bar is a row of images.
1969 * Modifying Menus:: How to add new items to a menu.
1972 @node Defining Menus
1973 @subsection Defining Menus
1974 @cindex defining menus
1975 @cindex menu prompt string
1976 @cindex prompt string (of menu)
1979 A keymap acts as a menu if it has an @dfn{overall prompt string},
1980 which is a string that appears as an element of the keymap.
1981 (@xref{Format of Keymaps}.) The string should describe the purpose of
1982 the menu's commands. Emacs displays the overall prompt string as the
1983 menu title in some cases, depending on the toolkit (if any) used for
1984 displaying menus.@footnote{It is required for menus which do not use a
1985 toolkit, e.g.@: under MS-DOS.} Keyboard menus also display the
1986 overall prompt string.
1988 The easiest way to construct a keymap with a prompt string is to
1989 specify the string as an argument when you call @code{make-keymap},
1990 @code{make-sparse-keymap} (@pxref{Creating Keymaps}), or
1991 @code{define-prefix-command} (@pxref{Definition of
1992 define-prefix-command}). If you do not want the keymap to operate as
1993 a menu, don't specify a prompt string for it.
1995 @defun keymap-prompt keymap
1996 This function returns the overall prompt string of @var{keymap},
1997 or @code{nil} if it has none.
2000 The menu's items are the bindings in the keymap. Each binding
2001 associates an event type to a definition, but the event types have no
2002 significance for the menu appearance. (Usually we use pseudo-events,
2003 symbols that the keyboard cannot generate, as the event types for menu
2004 item bindings.) The menu is generated entirely from the bindings that
2005 correspond in the keymap to these events.
2007 The order of items in the menu is the same as the order of bindings in
2008 the keymap. Since @code{define-key} puts new bindings at the front, you
2009 should define the menu items starting at the bottom of the menu and
2010 moving to the top, if you care about the order. When you add an item to
2011 an existing menu, you can specify its position in the menu using
2012 @code{define-key-after} (@pxref{Modifying Menus}).
2015 * Simple Menu Items:: A simple kind of menu key binding,
2016 limited in capabilities.
2017 * Extended Menu Items:: More powerful menu item definitions
2018 let you specify keywords to enable
2020 * Menu Separators:: Drawing a horizontal line through a menu.
2021 * Alias Menu Items:: Using command aliases in menu items.
2022 * Toolkit Differences:: Not all toolkits provide the same features.
2026 @node Simple Menu Items
2027 @subsubsection Simple Menu Items
2029 The simpler (and original) way to define a menu item is to bind some
2030 event type (it doesn't matter what event type) to a binding like this:
2033 (@var{item-string} . @var{real-binding})
2037 The @sc{car}, @var{item-string}, is the string to be displayed in the
2038 menu. It should be short---preferably one to three words. It should
2039 describe the action of the command it corresponds to. Note that not
2040 all graphical toolkits can display non-@acronym{ASCII} text in menus
2041 (it will work for keyboard menus and will work to a large extent with
2044 You can also supply a second string, called the help string, as follows:
2047 (@var{item-string} @var{help} . @var{real-binding})
2051 @var{help} specifies a ``help-echo'' string to display while the mouse
2052 is on that item in the same way as @code{help-echo} text properties
2053 (@pxref{Help display}).
2055 As far as @code{define-key} is concerned, @var{item-string} and
2056 @var{help-string} are part of the event's binding. However,
2057 @code{lookup-key} returns just @var{real-binding}, and only
2058 @var{real-binding} is used for executing the key.
2060 If @var{real-binding} is @code{nil}, then @var{item-string} appears in
2061 the menu but cannot be selected.
2063 If @var{real-binding} is a symbol and has a non-@code{nil}
2064 @code{menu-enable} property, that property is an expression that
2065 controls whether the menu item is enabled. Every time the keymap is
2066 used to display a menu, Emacs evaluates the expression, and it enables
2067 the menu item only if the expression's value is non-@code{nil}. When a
2068 menu item is disabled, it is displayed in a ``fuzzy'' fashion, and
2071 The menu bar does not recalculate which items are enabled every time you
2072 look at a menu. This is because the X toolkit requires the whole tree
2073 of menus in advance. To force recalculation of the menu bar, call
2074 @code{force-mode-line-update} (@pxref{Mode Line Format}).
2076 @node Extended Menu Items
2077 @subsubsection Extended Menu Items
2079 @cindex extended menu item
2081 An extended-format menu item is a more flexible and also cleaner
2082 alternative to the simple format. You define an event type with a
2083 binding that's a list starting with the symbol @code{menu-item}.
2084 For a non-selectable string, the binding looks like this:
2087 (menu-item @var{item-name})
2091 A string starting with two or more dashes specifies a separator line;
2092 see @ref{Menu Separators}.
2094 To define a real menu item which can be selected, the extended format
2095 binding looks like this:
2098 (menu-item @var{item-name} @var{real-binding}
2099 . @var{item-property-list})
2103 Here, @var{item-name} is an expression which evaluates to the menu item
2104 string. Thus, the string need not be a constant. The third element,
2105 @var{real-binding}, is the command to execute. The tail of the list,
2106 @var{item-property-list}, has the form of a property list which contains
2109 Here is a table of the properties that are supported:
2112 @item :enable @var{form}
2113 The result of evaluating @var{form} determines whether the item is
2114 enabled (non-@code{nil} means yes). If the item is not enabled,
2115 you can't really click on it.
2117 @item :visible @var{form}
2118 The result of evaluating @var{form} determines whether the item should
2119 actually appear in the menu (non-@code{nil} means yes). If the item
2120 does not appear, then the menu is displayed as if this item were
2123 @item :help @var{help}
2124 The value of this property, @var{help}, specifies a ``help-echo'' string
2125 to display while the mouse is on that item. This is displayed in the
2126 same way as @code{help-echo} text properties (@pxref{Help display}).
2127 Note that this must be a constant string, unlike the @code{help-echo}
2128 property for text and overlays.
2130 @item :button (@var{type} . @var{selected})
2131 This property provides a way to define radio buttons and toggle buttons.
2132 The @sc{car}, @var{type}, says which: it should be @code{:toggle} or
2133 @code{:radio}. The @sc{cdr}, @var{selected}, should be a form; the
2134 result of evaluating it says whether this button is currently selected.
2136 A @dfn{toggle} is a menu item which is labeled as either ``on'' or ``off''
2137 according to the value of @var{selected}. The command itself should
2138 toggle @var{selected}, setting it to @code{t} if it is @code{nil},
2139 and to @code{nil} if it is @code{t}. Here is how the menu item
2140 to toggle the @code{debug-on-error} flag is defined:
2143 (menu-item "Debug on Error" toggle-debug-on-error
2145 . (and (boundp 'debug-on-error)
2150 This works because @code{toggle-debug-on-error} is defined as a command
2151 which toggles the variable @code{debug-on-error}.
2153 @dfn{Radio buttons} are a group of menu items, in which at any time one
2154 and only one is ``selected''. There should be a variable whose value
2155 says which one is selected at any time. The @var{selected} form for
2156 each radio button in the group should check whether the variable has the
2157 right value for selecting that button. Clicking on the button should
2158 set the variable so that the button you clicked on becomes selected.
2160 @item :key-sequence @var{key-sequence}
2161 This property specifies which key sequence is likely to be bound to the
2162 same command invoked by this menu item. If you specify the right key
2163 sequence, that makes preparing the menu for display run much faster.
2165 If you specify the wrong key sequence, it has no effect; before Emacs
2166 displays @var{key-sequence} in the menu, it verifies that
2167 @var{key-sequence} is really equivalent to this menu item.
2169 @item :key-sequence nil
2170 This property indicates that there is normally no key binding which is
2171 equivalent to this menu item. Using this property saves time in
2172 preparing the menu for display, because Emacs does not need to search
2173 the keymaps for a keyboard equivalent for this menu item.
2175 However, if the user has rebound this item's definition to a key
2176 sequence, Emacs ignores the @code{:keys} property and finds the keyboard
2179 @item :keys @var{string}
2180 This property specifies that @var{string} is the string to display
2181 as the keyboard equivalent for this menu item. You can use
2182 the @samp{\\[...]} documentation construct in @var{string}.
2184 @item :filter @var{filter-fn}
2185 This property provides a way to compute the menu item dynamically.
2186 The property value @var{filter-fn} should be a function of one argument;
2187 when it is called, its argument will be @var{real-binding}. The
2188 function should return the binding to use instead.
2190 Emacs can call this function at any time that it does redisplay or
2191 operates on menu data structures, so you should write it so it can
2192 safely be called at any time.
2195 @node Menu Separators
2196 @subsubsection Menu Separators
2197 @cindex menu separators
2199 A menu separator is a kind of menu item that doesn't display any
2200 text---instead, it divides the menu into subparts with a horizontal line.
2201 A separator looks like this in the menu keymap:
2204 (menu-item @var{separator-type})
2208 where @var{separator-type} is a string starting with two or more dashes.
2210 In the simplest case, @var{separator-type} consists of only dashes.
2211 That specifies the default kind of separator. (For compatibility,
2212 @code{""} and @code{-} also count as separators.)
2214 Certain other values of @var{separator-type} specify a different
2215 style of separator. Here is a table of them:
2220 An extra vertical space, with no actual line.
2222 @item "--single-line"
2223 A single line in the menu's foreground color.
2225 @item "--double-line"
2226 A double line in the menu's foreground color.
2228 @item "--single-dashed-line"
2229 A single dashed line in the menu's foreground color.
2231 @item "--double-dashed-line"
2232 A double dashed line in the menu's foreground color.
2234 @item "--shadow-etched-in"
2235 A single line with a 3D sunken appearance. This is the default,
2236 used separators consisting of dashes only.
2238 @item "--shadow-etched-out"
2239 A single line with a 3D raised appearance.
2241 @item "--shadow-etched-in-dash"
2242 A single dashed line with a 3D sunken appearance.
2244 @item "--shadow-etched-out-dash"
2245 A single dashed line with a 3D raised appearance.
2247 @item "--shadow-double-etched-in"
2248 Two lines with a 3D sunken appearance.
2250 @item "--shadow-double-etched-out"
2251 Two lines with a 3D raised appearance.
2253 @item "--shadow-double-etched-in-dash"
2254 Two dashed lines with a 3D sunken appearance.
2256 @item "--shadow-double-etched-out-dash"
2257 Two dashed lines with a 3D raised appearance.
2260 You can also give these names in another style, adding a colon after
2261 the double-dash and replacing each single dash with capitalization of
2262 the following word. Thus, @code{"--:singleLine"}, is equivalent to
2263 @code{"--single-line"}.
2265 You can use a longer form to specify keywords such as @code{:enable}
2266 and @code{:visible} for a menu separator:
2268 @code{(menu-item @var{separator-type} nil . @var{item-property-list})}
2273 (menu-item "--" nil :visible (boundp 'foo))
2276 Some systems and display toolkits don't really handle all of these
2277 separator types. If you use a type that isn't supported, the menu
2278 displays a similar kind of separator that is supported.
2280 @node Alias Menu Items
2281 @subsubsection Alias Menu Items
2283 Sometimes it is useful to make menu items that use the ``same''
2284 command but with different enable conditions. The best way to do this
2285 in Emacs now is with extended menu items; before that feature existed,
2286 it could be done by defining alias commands and using them in menu
2287 items. Here's an example that makes two aliases for
2288 @code{toggle-read-only} and gives them different enable conditions:
2291 (defalias 'make-read-only 'toggle-read-only)
2292 (put 'make-read-only 'menu-enable '(not buffer-read-only))
2293 (defalias 'make-writable 'toggle-read-only)
2294 (put 'make-writable 'menu-enable 'buffer-read-only)
2297 When using aliases in menus, often it is useful to display the
2298 equivalent key bindings for the ``real'' command name, not the aliases
2299 (which typically don't have any key bindings except for the menu
2300 itself). To request this, give the alias symbol a non-@code{nil}
2301 @code{menu-alias} property. Thus,
2304 (put 'make-read-only 'menu-alias t)
2305 (put 'make-writable 'menu-alias t)
2309 causes menu items for @code{make-read-only} and @code{make-writable} to
2310 show the keyboard bindings for @code{toggle-read-only}.
2312 @node Toolkit Differences
2313 @subsubsection Toolkit Differences
2315 The various toolkits with which you can build Emacs do not all support
2316 the same set of features for menus. Some code works as expected with
2317 one toolkit, but not under another.
2319 One example is menu actions or buttons in a top-level menu bar. The
2320 following works with the Lucid toolkit or on MS Windows, but not with
2321 GTK or Nextstep, where clicking on the item has no effect.
2324 (defun menu-action-greet ()
2326 (message "Hello Emacs User!"))
2328 (defun top-level-menu ()
2330 (define-key lisp-interaction-mode-map [menu-bar m]
2331 '(menu-item "Action Button" menu-action-greet)))
2335 @subsection Menus and the Mouse
2337 The usual way to make a menu keymap produce a menu is to make it the
2338 definition of a prefix key. (A Lisp program can explicitly pop up a
2339 menu and receive the user's choice---see @ref{Pop-Up Menus}.)
2341 If the prefix key ends with a mouse event, Emacs handles the menu keymap
2342 by popping up a visible menu, so that the user can select a choice with
2343 the mouse. When the user clicks on a menu item, the event generated is
2344 whatever character or symbol has the binding that brought about that
2345 menu item. (A menu item may generate a series of events if the menu has
2346 multiple levels or comes from the menu bar.)
2348 It's often best to use a button-down event to trigger the menu. Then
2349 the user can select a menu item by releasing the button.
2352 If the menu keymap contains a binding to a nested keymap, the nested
2353 keymap specifies a @dfn{submenu}. There will be a menu item, labeled
2354 by the nested keymap's item string, and clicking on this item
2355 automatically pops up the specified submenu. As a special exception,
2356 if the menu keymap contains a single nested keymap and no other menu
2357 items, the menu shows the contents of the nested keymap directly, not
2360 However, if Emacs is compiled without X toolkit support, submenus
2361 are not supported. Each nested keymap is shown as a menu item, but
2362 clicking on it does not automatically pop up the submenu. If you wish
2363 to imitate the effect of submenus, you can do that by giving a nested
2364 keymap an item string which starts with @samp{@@}. This causes Emacs
2365 to display the nested keymap using a separate @dfn{menu pane}; the
2366 rest of the item string after the @samp{@@} is the pane label. If
2367 Emacs is compiled without X toolkit support, menu panes are not used;
2368 in that case, a @samp{@@} at the beginning of an item string is
2369 omitted when the menu label is displayed, and has no other effect.
2371 @node Keyboard Menus
2372 @subsection Menus and the Keyboard
2374 When a prefix key ending with a keyboard event (a character or
2375 function key) has a definition that is a menu keymap, the keymap
2376 operates as a keyboard menu; the user specifies the next event by
2377 choosing a menu item with the keyboard.
2379 Emacs displays the keyboard menu with the map's overall prompt
2380 string, followed by the alternatives (the item strings of the map's
2381 bindings), in the echo area. If the bindings don't all fit at once,
2382 the user can type @key{SPC} to see the next line of alternatives.
2383 Successive uses of @key{SPC} eventually get to the end of the menu and
2384 then cycle around to the beginning. (The variable
2385 @code{menu-prompt-more-char} specifies which character is used for
2386 this; @key{SPC} is the default.)
2388 When the user has found the desired alternative from the menu, he or
2389 she should type the corresponding character---the one whose binding is
2392 @defvar menu-prompt-more-char
2393 This variable specifies the character to use to ask to see
2394 the next line of a menu. Its initial value is 32, the code
2399 @subsection Menu Example
2400 @cindex menu definition example
2402 Here is a complete example of defining a menu keymap. It is the
2403 definition of the @samp{Replace} submenu in the @samp{Edit} menu in
2404 the menu bar, and it uses the extended menu item format
2405 (@pxref{Extended Menu Items}). First we create the keymap, and give
2409 (defvar menu-bar-replace-menu (make-sparse-keymap "Replace"))
2413 Next we define the menu items:
2416 (define-key menu-bar-replace-menu [tags-repl-continue]
2417 '(menu-item "Continue Replace" tags-loop-continue
2418 :help "Continue last tags replace operation"))
2419 (define-key menu-bar-replace-menu [tags-repl]
2420 '(menu-item "Replace in tagged files" tags-query-replace
2421 :help "Interactively replace a regexp in all tagged files"))
2422 (define-key menu-bar-replace-menu [separator-replace-tags]
2428 Note the symbols which the bindings are ``made for''; these appear
2429 inside square brackets, in the key sequence being defined. In some
2430 cases, this symbol is the same as the command name; sometimes it is
2431 different. These symbols are treated as ``function keys'', but they are
2432 not real function keys on the keyboard. They do not affect the
2433 functioning of the menu itself, but they are ``echoed'' in the echo area
2434 when the user selects from the menu, and they appear in the output of
2435 @code{where-is} and @code{apropos}.
2437 The menu in this example is intended for use with the mouse. If a
2438 menu is intended for use with the keyboard, that is, if it is bound to
2439 a key sequence ending with a keyboard event, then the menu items
2440 should be bound to characters or ``real'' function keys, that can be
2441 typed with the keyboard.
2443 The binding whose definition is @code{("--")} is a separator line.
2444 Like a real menu item, the separator has a key symbol, in this case
2445 @code{separator-replace-tags}. If one menu has two separators, they
2446 must have two different key symbols.
2448 Here is how we make this menu appear as an item in the parent menu:
2451 (define-key menu-bar-edit-menu [replace]
2452 (list 'menu-item "Replace" menu-bar-replace-menu))
2456 Note that this incorporates the submenu keymap, which is the value of
2457 the variable @code{menu-bar-replace-menu}, rather than the symbol
2458 @code{menu-bar-replace-menu} itself. Using that symbol in the parent
2459 menu item would be meaningless because @code{menu-bar-replace-menu} is
2462 If you wanted to attach the same replace menu to a mouse click, you
2466 (define-key global-map [C-S-down-mouse-1]
2467 menu-bar-replace-menu)
2471 @subsection The Menu Bar
2474 On graphical displays, there is usually a @dfn{menu bar} at the top
2475 of each frame. @xref{Menu Bars,,,emacs, The GNU Emacs Manual}. Menu
2476 bar items are subcommands of the fake ``function key''
2477 @code{menu-bar}, as defined in the active keymaps.
2479 To add an item to the menu bar, invent a fake ``function key'' of your
2480 own (let's call it @var{key}), and make a binding for the key sequence
2481 @code{[menu-bar @var{key}]}. Most often, the binding is a menu keymap,
2482 so that pressing a button on the menu bar item leads to another menu.
2484 When more than one active keymap defines the same ``function key''
2485 for the menu bar, the item appears just once. If the user clicks on
2486 that menu bar item, it brings up a single, combined menu containing
2487 all the subcommands of that item---the global subcommands, the local
2488 subcommands, and the minor mode subcommands.
2490 The variable @code{overriding-local-map} is normally ignored when
2491 determining the menu bar contents. That is, the menu bar is computed
2492 from the keymaps that would be active if @code{overriding-local-map}
2493 were @code{nil}. @xref{Active Keymaps}.
2495 Here's an example of setting up a menu bar item:
2499 ;; @r{Make a menu keymap (with a prompt string)}
2500 ;; @r{and make it the menu bar item's definition.}
2501 (define-key global-map [menu-bar words]
2502 (cons "Words" (make-sparse-keymap "Words")))
2506 ;; @r{Define specific subcommands in this menu.}
2507 (define-key global-map
2508 [menu-bar words forward]
2509 '("Forward word" . forward-word))
2512 (define-key global-map
2513 [menu-bar words backward]
2514 '("Backward word" . backward-word))
2518 A local keymap can cancel a menu bar item made by the global keymap by
2519 rebinding the same fake function key with @code{undefined} as the
2520 binding. For example, this is how Dired suppresses the @samp{Edit} menu
2524 (define-key dired-mode-map [menu-bar edit] 'undefined)
2528 Here, @code{edit} is the fake function key used by the global map for
2529 the @samp{Edit} menu bar item. The main reason to suppress a global
2530 menu bar item is to regain space for mode-specific items.
2532 @defvar menu-bar-final-items
2533 Normally the menu bar shows global items followed by items defined by the
2536 This variable holds a list of fake function keys for items to display at
2537 the end of the menu bar rather than in normal sequence. The default
2538 value is @code{(help-menu)}; thus, the @samp{Help} menu item normally appears
2539 at the end of the menu bar, following local menu items.
2542 @defvar menu-bar-update-hook
2543 This normal hook is run by redisplay to update the menu bar contents,
2544 before redisplaying the menu bar. You can use it to update submenus
2545 whose contents should vary. Since this hook is run frequently, we
2546 advise you to ensure that the functions it calls do not take much time
2550 Next to every menu bar item, Emacs displays a key binding that runs
2551 the same command (if such a key binding exists). This serves as a
2552 convenient hint for users who do not know the key binding. If a
2553 command has multiple bindings, Emacs normally displays the first one
2554 it finds. You can specify one particular key binding by assigning an
2555 @code{:advertised-binding} symbol property to the command. @xref{Keys
2559 @subsection Tool bars
2562 A @dfn{tool bar} is a row of clickable icons at the top of a frame,
2563 just below the menu bar. @xref{Tool Bars,,,emacs, The GNU Emacs
2566 On each frame, the frame parameter @code{tool-bar-lines} controls
2567 how many lines' worth of height to reserve for the tool bar. A zero
2568 value suppresses the tool bar. If the value is nonzero, and
2569 @code{auto-resize-tool-bars} is non-@code{nil}, the tool bar expands
2570 and contracts automatically as needed to hold the specified contents.
2571 If the value is @code{grow-only}, the tool bar expands automatically,
2572 but does not contract automatically.
2574 The tool bar contents are controlled by a menu keymap attached to a
2575 fake ``function key'' called @code{tool-bar} (much like the way the menu
2576 bar is controlled). So you define a tool bar item using
2577 @code{define-key}, like this:
2580 (define-key global-map [tool-bar @var{key}] @var{item})
2584 where @var{key} is a fake ``function key'' to distinguish this item from
2585 other items, and @var{item} is a menu item key binding (@pxref{Extended
2586 Menu Items}), which says how to display this item and how it behaves.
2588 The usual menu keymap item properties, @code{:visible},
2589 @code{:enable}, @code{:button}, and @code{:filter}, are useful in
2590 tool bar bindings and have their normal meanings. The @var{real-binding}
2591 in the item must be a command, not a keymap; in other words, it does not
2592 work to define a tool bar icon as a prefix key.
2594 The @code{:help} property specifies a ``help-echo'' string to display
2595 while the mouse is on that item. This is displayed in the same way as
2596 @code{help-echo} text properties (@pxref{Help display}).
2598 In addition, you should use the @code{:image} property;
2599 this is how you specify the image to display in the tool bar:
2602 @item :image @var{image}
2603 @var{images} is either a single image specification or a vector of four
2604 image specifications. If you use a vector of four,
2605 one of them is used, depending on circumstances:
2609 Used when the item is enabled and selected.
2611 Used when the item is enabled and deselected.
2613 Used when the item is disabled and selected.
2615 Used when the item is disabled and deselected.
2619 If @var{image} is a single image specification, Emacs draws the tool bar
2620 button in disabled state by applying an edge-detection algorithm to the
2623 The @code{:rtl} property specifies an alternative image to use for
2624 right-to-left languages. Only the GTK+ version of Emacs supports this
2627 Like the menu bar, the tool bar can display separators (@pxref{Menu
2628 Separators}). Tool bar separators are vertical rather than
2629 horizontal, though, and only a single style is supported. They are
2630 represented in the tool bar keymap by @code{(menu-item "--")} entries;
2631 properties like @code{:visible} are not supported for tool bar
2632 separators. Separators are rendered natively in GTK+ and Nextstep
2633 tool bars; in the other cases, they are rendered using an image of a
2636 The default tool bar is defined so that items specific to editing do not
2637 appear for major modes whose command symbol has a @code{mode-class}
2638 property of @code{special} (@pxref{Major Mode Conventions}). Major
2639 modes may add items to the global bar by binding @code{[tool-bar
2640 @var{foo}]} in their local map. It makes sense for some major modes to
2641 replace the default tool bar items completely, since not many can be
2642 accommodated conveniently, and the default bindings make this easy by
2643 using an indirection through @code{tool-bar-map}.
2645 @defvar tool-bar-map
2646 By default, the global map binds @code{[tool-bar]} as follows:
2649 (global-set-key [tool-bar]
2650 `(menu-item ,(purecopy "tool bar") ignore
2651 :filter tool-bar-make-keymap))
2655 The function @code{tool-bar-make-keymap}, in turn, derives the actual
2656 tool bar map dynamically from the value of the variable
2657 @code{tool-bar-map}. Hence, you should normally adjust the default
2658 (global) tool bar by changing that map. Some major modes, such as
2659 Info mode, completely replace the global tool bar by making
2660 @code{tool-bar-map} buffer-local and setting it to a different keymap.
2663 There are two convenience functions for defining tool bar items, as
2666 @defun tool-bar-add-item icon def key &rest props
2667 This function adds an item to the tool bar by modifying
2668 @code{tool-bar-map}. The image to use is defined by @var{icon}, which
2669 is the base name of an XPM, XBM or PBM image file to be located by
2670 @code{find-image}. Given a value @samp{"exit"}, say, @file{exit.xpm},
2671 @file{exit.pbm} and @file{exit.xbm} would be searched for in that order
2672 on a color display. On a monochrome display, the search order is
2673 @samp{.pbm}, @samp{.xbm} and @samp{.xpm}. The binding to use is the
2674 command @var{def}, and @var{key} is the fake function key symbol in the
2675 prefix keymap. The remaining arguments @var{props} are additional
2676 property list elements to add to the menu item specification.
2678 To define items in some local map, bind @code{tool-bar-map} with
2679 @code{let} around calls of this function:
2681 (defvar foo-tool-bar-map
2682 (let ((tool-bar-map (make-sparse-keymap)))
2683 (tool-bar-add-item @dots{})
2689 @defun tool-bar-add-item-from-menu command icon &optional map &rest props
2690 This function is a convenience for defining tool bar items which are
2691 consistent with existing menu bar bindings. The binding of
2692 @var{command} is looked up in the menu bar in @var{map} (default
2693 @code{global-map}) and modified to add an image specification for
2694 @var{icon}, which is found in the same way as by
2695 @code{tool-bar-add-item}. The resulting binding is then placed in
2696 @code{tool-bar-map}, so use this function only for global tool bar
2699 @var{map} must contain an appropriate keymap bound to
2700 @code{[menu-bar]}. The remaining arguments @var{props} are additional
2701 property list elements to add to the menu item specification.
2704 @defun tool-bar-local-item-from-menu command icon in-map &optional from-map &rest props
2705 This function is used for making non-global tool bar items. Use it
2706 like @code{tool-bar-add-item-from-menu} except that @var{in-map}
2707 specifies the local map to make the definition in. The argument
2708 @var{from-map} is like the @var{map} argument of
2709 @code{tool-bar-add-item-from-menu}.
2712 @defvar auto-resize-tool-bars
2713 If this variable is non-@code{nil}, the tool bar automatically resizes to
2714 show all defined tool bar items---but not larger than a quarter of the
2717 If the value is @code{grow-only}, the tool bar expands automatically,
2718 but does not contract automatically. To contract the tool bar, the
2719 user has to redraw the frame by entering @kbd{C-l}.
2721 If Emacs is built with GTK or Nextstep, the tool bar can only show one
2722 line, so this variable has no effect.
2725 @defvar auto-raise-tool-bar-buttons
2726 If this variable is non-@code{nil}, tool bar items display
2727 in raised form when the mouse moves over them.
2730 @defvar tool-bar-button-margin
2731 This variable specifies an extra margin to add around tool bar items.
2732 The value is an integer, a number of pixels. The default is 4.
2735 @defvar tool-bar-button-relief
2736 This variable specifies the shadow width for tool bar items.
2737 The value is an integer, a number of pixels. The default is 1.
2740 @defvar tool-bar-border
2741 This variable specifies the height of the border drawn below the tool
2742 bar area. An integer value specifies height as a number of pixels.
2743 If the value is one of @code{internal-border-width} (the default) or
2744 @code{border-width}, the tool bar border height corresponds to the
2745 corresponding frame parameter.
2748 You can define a special meaning for clicking on a tool bar item with
2749 the shift, control, meta, etc., modifiers. You do this by setting up
2750 additional items that relate to the original item through the fake
2751 function keys. Specifically, the additional items should use the
2752 modified versions of the same fake function key used to name the
2755 Thus, if the original item was defined this way,
2758 (define-key global-map [tool-bar shell]
2759 '(menu-item "Shell" shell
2760 :image (image :type xpm :file "shell.xpm")))
2764 then here is how you can define clicking on the same tool bar image with
2768 (define-key global-map [tool-bar S-shell] 'some-command)
2771 @xref{Function Keys}, for more information about how to add modifiers to
2774 @node Modifying Menus
2775 @subsection Modifying Menus
2777 When you insert a new item in an existing menu, you probably want to
2778 put it in a particular place among the menu's existing items. If you
2779 use @code{define-key} to add the item, it normally goes at the front of
2780 the menu. To put it elsewhere in the menu, use @code{define-key-after}:
2782 @defun define-key-after map key binding &optional after
2783 Define a binding in @var{map} for @var{key}, with value @var{binding},
2784 just like @code{define-key}, but position the binding in @var{map} after
2785 the binding for the event @var{after}. The argument @var{key} should be
2786 of length one---a vector or string with just one element. But
2787 @var{after} should be a single event type---a symbol or a character, not
2788 a sequence. The new binding goes after the binding for @var{after}. If
2789 @var{after} is @code{t} or is omitted, then the new binding goes last, at
2790 the end of the keymap. However, new bindings are added before any
2796 (define-key-after my-menu [drink]
2797 '("Drink" . drink-command) 'eat)
2801 makes a binding for the fake function key @key{DRINK} and puts it
2802 right after the binding for @key{EAT}.
2804 Here is how to insert an item called @samp{Work} in the @samp{Signals}
2805 menu of Shell mode, after the item @code{break}:
2809 (lookup-key shell-mode-map [menu-bar signals])
2810 [work] '("Work" . work-command) 'break)