2 @c This is part of the GNU Emacs Lisp Reference Manual.
3 @c Copyright (C) 1990-1994, 1998-2011 Free Software Foundation, Inc.
4 @c See the file elisp.texi for copying conditions.
5 @setfilename ../../info/keymaps
6 @node Keymaps, Modes, Command Loop, Top
10 The command bindings of input events are recorded in data structures
11 called @dfn{keymaps}. Each entry in a keymap associates (or
12 @dfn{binds}) an individual event type, either to another keymap or to
13 a command. When an event type is bound to a keymap, that keymap is
14 used to look up the next input event; this continues until a command
15 is found. The whole process is called @dfn{key lookup}.
18 * Key Sequences:: Key sequences as Lisp objects.
19 * Keymap Basics:: Basic concepts of keymaps.
20 * Format of Keymaps:: What a keymap looks like as a Lisp object.
21 * Creating Keymaps:: Functions to create and copy keymaps.
22 * Inheritance and Keymaps:: How one keymap can inherit the bindings
24 * Prefix Keys:: Defining a key with a keymap as its definition.
25 * Active Keymaps:: How Emacs searches the active keymaps
27 * Searching Keymaps:: A pseudo-Lisp summary of searching active maps.
28 * Controlling Active Maps:: Each buffer has a local keymap
29 to override the standard (global) bindings.
30 A minor mode can also override them.
31 * Key Lookup:: Finding a key's binding in one keymap.
32 * Functions for Key Lookup:: How to request key lookup.
33 * Changing Key Bindings:: Redefining a key in a keymap.
34 * Remapping Commands:: A keymap can translate one command to another.
35 * Translation Keymaps:: Keymaps for translating sequences of events.
36 * Key Binding Commands:: Interactive interfaces for redefining keys.
37 * Scanning Keymaps:: Looking through all keymaps, for printing help.
38 * Menu Keymaps:: Defining a menu as a keymap.
42 @section Key Sequences
47 A @dfn{key sequence}, or @dfn{key} for short, is a sequence of one
48 or more input events that form a unit. Input events include
49 characters, function keys, and mouse actions (@pxref{Input Events}).
50 The Emacs Lisp representation for a key sequence is a string or
51 vector. Unless otherwise stated, any Emacs Lisp function that accepts
52 a key sequence as an argument can handle both representations.
54 In the string representation, alphanumeric characters ordinarily
55 stand for themselves; for example, @code{"a"} represents @kbd{a}
56 and @code{"2"} represents @kbd{2}. Control character events are
57 prefixed by the substring @code{"\C-"}, and meta characters by
58 @code{"\M-"}; for example, @code{"\C-x"} represents the key @kbd{C-x}.
59 In addition, the @key{TAB}, @key{RET}, @key{ESC}, and @key{DEL} events
60 are represented by @code{"\t"}, @code{"\r"}, @code{"\e"}, and
61 @code{"\d"} respectively. The string representation of a complete key
62 sequence is the concatenation of the string representations of the
63 constituent events; thus, @code{"\C-xl"} represents the key sequence
66 Key sequences containing function keys, mouse button events, or
67 non-ASCII characters such as @kbd{C-=} or @kbd{H-a} cannot be
68 represented as strings; they have to be represented as vectors.
70 In the vector representation, each element of the vector represents
71 an input event, in its Lisp form. @xref{Input Events}. For example,
72 the vector @code{[?\C-x ?l]} represents the key sequence @kbd{C-x l}.
74 For examples of key sequences written in string and vector
75 representations, @ref{Init Rebinding,,, emacs, The GNU Emacs Manual}.
77 @defmac kbd keyseq-text
78 This macro converts the text @var{keyseq-text} (a string constant)
79 into a key sequence (a string or vector constant). The contents of
80 @var{keyseq-text} should describe the key sequence using almost the same
81 syntax used in this manual. More precisely, it uses the same syntax
82 that Edit Macro mode uses for editing keyboard macros (@pxref{Edit
83 Keyboard Macro,,, emacs, The GNU Emacs Manual}); you must surround
84 function key names with @samp{<@dots{}>}.
87 (kbd "C-x") @result{} "\C-x"
88 (kbd "C-x C-f") @result{} "\C-x\C-f"
89 (kbd "C-x 4 C-f") @result{} "\C-x4\C-f"
90 (kbd "X") @result{} "X"
91 (kbd "RET") @result{} "\^M"
92 (kbd "C-c SPC") @result{} "\C-c@ "
93 (kbd "<f1> SPC") @result{} [f1 32]
94 (kbd "C-M-<down>") @result{} [C-M-down]
97 This macro is not meant for use with arguments that vary---only
98 with string constants.
102 @section Keymap Basics
104 @cindex binding of a key
106 @cindex undefined key
108 A keymap is a Lisp data structure that specifies @dfn{key bindings}
109 for various key sequences.
111 A single keymap directly specifies definitions for individual
112 events. When a key sequence consists of a single event, its binding
113 in a keymap is the keymap's definition for that event. The binding of
114 a longer key sequence is found by an iterative process: first find the
115 definition of the first event (which must itself be a keymap); then
116 find the second event's definition in that keymap, and so on until all
117 the events in the key sequence have been processed.
119 If the binding of a key sequence is a keymap, we call the key sequence
120 a @dfn{prefix key}. Otherwise, we call it a @dfn{complete key} (because
121 no more events can be added to it). If the binding is @code{nil},
122 we call the key @dfn{undefined}. Examples of prefix keys are @kbd{C-c},
123 @kbd{C-x}, and @kbd{C-x 4}. Examples of defined complete keys are
124 @kbd{X}, @key{RET}, and @kbd{C-x 4 C-f}. Examples of undefined complete
125 keys are @kbd{C-x C-g}, and @kbd{C-c 3}. @xref{Prefix Keys}, for more
128 The rule for finding the binding of a key sequence assumes that the
129 intermediate bindings (found for the events before the last) are all
130 keymaps; if this is not so, the sequence of events does not form a
131 unit---it is not really one key sequence. In other words, removing one
132 or more events from the end of any valid key sequence must always yield
133 a prefix key. For example, @kbd{C-f C-n} is not a key sequence;
134 @kbd{C-f} is not a prefix key, so a longer sequence starting with
135 @kbd{C-f} cannot be a key sequence.
137 The set of possible multi-event key sequences depends on the bindings
138 for prefix keys; therefore, it can be different for different keymaps,
139 and can change when bindings are changed. However, a one-event sequence
140 is always a key sequence, because it does not depend on any prefix keys
141 for its well-formedness.
143 At any time, several primary keymaps are @dfn{active}---that is, in
144 use for finding key bindings. These are the @dfn{global map}, which is
145 shared by all buffers; the @dfn{local keymap}, which is usually
146 associated with a specific major mode; and zero or more @dfn{minor mode
147 keymaps}, which belong to currently enabled minor modes. (Not all minor
148 modes have keymaps.) The local keymap bindings shadow (i.e., take
149 precedence over) the corresponding global bindings. The minor mode
150 keymaps shadow both local and global keymaps. @xref{Active Keymaps},
153 @node Format of Keymaps
154 @section Format of Keymaps
155 @cindex format of keymaps
156 @cindex keymap format
158 @cindex sparse keymap
160 Each keymap is a list whose @sc{car} is the symbol @code{keymap}. The
161 remaining elements of the list define the key bindings of the keymap.
162 A symbol whose function definition is a keymap is also a keymap. Use
163 the function @code{keymapp} (see below) to test whether an object is a
166 Several kinds of elements may appear in a keymap, after the symbol
167 @code{keymap} that begins it:
170 @item (@var{type} .@: @var{binding})
171 This specifies one binding, for events of type @var{type}. Each
172 ordinary binding applies to events of a particular @dfn{event type},
173 which is always a character or a symbol. @xref{Classifying Events}.
174 In this kind of binding, @var{binding} is a command.
176 @item (@var{type} @var{item-name} @r{[}@var{cache}@r{]} .@: @var{binding})
177 This specifies a binding which is also a simple menu item that
178 displays as @var{item-name} in the menu. @var{cache}, if present,
179 caches certain information for display in the menu. @xref{Simple Menu
182 @item (@var{type} @var{item-name} @var{help-string} @r{[}@var{cache}@r{]} .@: @var{binding})
183 This is a simple menu item with help string @var{help-string}.
185 @item (@var{type} menu-item .@: @var{details})
186 This specifies a binding which is also an extended menu item. This
187 allows use of other features. @xref{Extended Menu Items}.
189 @item (t .@: @var{binding})
190 @cindex default key binding
191 This specifies a @dfn{default key binding}; any event not bound by other
192 elements of the keymap is given @var{binding} as its binding. Default
193 bindings allow a keymap to bind all possible event types without having
194 to enumerate all of them. A keymap that has a default binding
195 completely masks any lower-precedence keymap, except for events
196 explicitly bound to @code{nil} (see below).
198 @item @var{char-table}
199 If an element of a keymap is a char-table, it counts as holding
200 bindings for all character events with no modifier bits
201 (@pxref{modifier bits}): element @var{n} is the binding for the
202 character with code @var{n}. This is a compact way to record lots of
203 bindings. A keymap with such a char-table is called a @dfn{full
204 keymap}. Other keymaps are called @dfn{sparse keymaps}.
207 @cindex keymap prompt string
208 @cindex overall prompt string
209 @cindex prompt string of keymap
210 Aside from elements that specify bindings for keys, a keymap can also
211 have a string as an element. This is called the @dfn{overall prompt
212 string} and makes it possible to use the keymap as a menu.
213 @xref{Defining Menus}.
216 When the binding is @code{nil}, it doesn't constitute a definition
217 but it does take precedence over a default binding or a binding in the
218 parent keymap. On the other hand, a binding of @code{nil} does
219 @emph{not} override lower-precedence keymaps; thus, if the local map
220 gives a binding of @code{nil}, Emacs uses the binding from the
223 @cindex meta characters lookup
224 Keymaps do not directly record bindings for the meta characters.
225 Instead, meta characters are regarded for purposes of key lookup as
226 sequences of two characters, the first of which is @key{ESC} (or
227 whatever is currently the value of @code{meta-prefix-char}). Thus, the
228 key @kbd{M-a} is internally represented as @kbd{@key{ESC} a}, and its
229 global binding is found at the slot for @kbd{a} in @code{esc-map}
230 (@pxref{Prefix Keys}).
232 This conversion applies only to characters, not to function keys or
233 other input events; thus, @kbd{M-@key{end}} has nothing to do with
234 @kbd{@key{ESC} @key{end}}.
236 Here as an example is the local keymap for Lisp mode, a sparse
237 keymap. It defines bindings for @key{DEL} and @key{TAB}, plus @kbd{C-c
238 C-l}, @kbd{M-C-q}, and @kbd{M-C-x}.
253 ;; @r{@kbd{M-C-x}, treated as @kbd{@key{ESC} C-x}}
254 (24 . lisp-send-defun)
256 ;; @r{@kbd{M-C-q}, treated as @kbd{@key{ESC} C-q}}
260 ;; @r{This part is inherited from @code{lisp-mode-shared-map}.}
263 (127 . backward-delete-char-untabify)
267 ;; @r{@kbd{M-C-q}, treated as @kbd{@key{ESC} C-q}}
269 (9 . lisp-indent-line))
273 @defun keymapp object
274 This function returns @code{t} if @var{object} is a keymap, @code{nil}
275 otherwise. More precisely, this function tests for a list whose
276 @sc{car} is @code{keymap}, or for a symbol whose function definition
277 satisfies @code{keymapp}.
285 (fset 'foo '(keymap))
290 (keymapp (current-global-map))
296 @node Creating Keymaps
297 @section Creating Keymaps
298 @cindex creating keymaps
300 Here we describe the functions for creating keymaps.
302 @defun make-sparse-keymap &optional prompt
303 This function creates and returns a new sparse keymap with no entries.
304 (A sparse keymap is the kind of keymap you usually want.) The new
305 keymap does not contain a char-table, unlike @code{make-keymap}, and
306 does not bind any events.
315 If you specify @var{prompt}, that becomes the overall prompt string
316 for the keymap. You should specify this only for menu keymaps
317 (@pxref{Defining Menus}). A keymap with an overall prompt string will
318 always present a mouse menu or a keyboard menu if it is active for
319 looking up the next input event. Don't specify an overall prompt string
320 for the main map of a major or minor mode, because that would cause
321 the command loop to present a keyboard menu every time.
324 @defun make-keymap &optional prompt
325 This function creates and returns a new full keymap. That keymap
326 contains a char-table (@pxref{Char-Tables}) with slots for all
327 characters without modifiers. The new keymap initially binds all
328 these characters to @code{nil}, and does not bind any other kind of
329 event. The argument @var{prompt} specifies a
330 prompt string, as in @code{make-sparse-keymap}.
335 @result{} (keymap #^[t nil nil nil @dots{} nil nil keymap])
339 A full keymap is more efficient than a sparse keymap when it holds
340 lots of bindings; for just a few, the sparse keymap is better.
343 @defun copy-keymap keymap
344 This function returns a copy of @var{keymap}. Any keymaps that
345 appear directly as bindings in @var{keymap} are also copied recursively,
346 and so on to any number of levels. However, recursive copying does not
347 take place when the definition of a character is a symbol whose function
348 definition is a keymap; the same symbol appears in the new copy.
353 (setq map (copy-keymap (current-local-map)))
357 ;; @r{(This implements meta characters.)}
359 (83 . center-paragraph)
361 (9 . tab-to-tab-stop))
365 (eq map (current-local-map))
369 (equal map (current-local-map))
375 @node Inheritance and Keymaps
376 @section Inheritance and Keymaps
377 @cindex keymap inheritance
378 @cindex inheriting a keymap's bindings
380 A keymap can inherit the bindings of another keymap, which we call the
381 @dfn{parent keymap}. Such a keymap looks like this:
384 (keymap @var{elements}@dots{} . @var{parent-keymap})
388 The effect is that this keymap inherits all the bindings of
389 @var{parent-keymap}, whatever they may be at the time a key is looked up,
390 but can add to them or override them with @var{elements}.
392 If you change the bindings in @var{parent-keymap} using
393 @code{define-key} or other key-binding functions, these changed
394 bindings are visible in the inheriting keymap, unless shadowed by the
395 bindings made by @var{elements}. The converse is not true: if you use
396 @code{define-key} to change bindings in the inheriting keymap, these
397 changes are recorded in @var{elements}, but have no effect on
400 The proper way to construct a keymap with a parent is to use
401 @code{set-keymap-parent}; if you have code that directly constructs a
402 keymap with a parent, please convert the program to use
403 @code{set-keymap-parent} instead.
405 @defun keymap-parent keymap
406 This returns the parent keymap of @var{keymap}. If @var{keymap}
407 has no parent, @code{keymap-parent} returns @code{nil}.
410 @defun set-keymap-parent keymap parent
411 This sets the parent keymap of @var{keymap} to @var{parent}, and returns
412 @var{parent}. If @var{parent} is @code{nil}, this function gives
413 @var{keymap} no parent at all.
415 If @var{keymap} has submaps (bindings for prefix keys), they too receive
416 new parent keymaps that reflect what @var{parent} specifies for those
420 Here is an example showing how to make a keymap that inherits
421 from @code{text-mode-map}:
424 (let ((map (make-sparse-keymap)))
425 (set-keymap-parent map text-mode-map)
429 A non-sparse keymap can have a parent too, but this is not very
430 useful. A non-sparse keymap always specifies something as the binding
431 for every numeric character code without modifier bits, even if it is
432 @code{nil}, so these character's bindings are never inherited from
439 A @dfn{prefix key} is a key sequence whose binding is a keymap. The
440 keymap defines what to do with key sequences that extend the prefix key.
441 For example, @kbd{C-x} is a prefix key, and it uses a keymap that is
442 also stored in the variable @code{ctl-x-map}. This keymap defines
443 bindings for key sequences starting with @kbd{C-x}.
445 Some of the standard Emacs prefix keys use keymaps that are
446 also found in Lisp variables:
452 @code{esc-map} is the global keymap for the @key{ESC} prefix key. Thus,
453 the global definitions of all meta characters are actually found here.
454 This map is also the function definition of @code{ESC-prefix}.
458 @code{help-map} is the global keymap for the @kbd{C-h} prefix key.
462 @vindex mode-specific-map
463 @code{mode-specific-map} is the global keymap for the prefix key
464 @kbd{C-c}. This map is actually global, not mode-specific, but its name
465 provides useful information about @kbd{C-c} in the output of @kbd{C-h b}
466 (@code{display-bindings}), since the main use of this prefix key is for
467 mode-specific bindings.
472 @findex Control-X-prefix
473 @code{ctl-x-map} is the global keymap used for the @kbd{C-x} prefix key.
474 This map is found via the function cell of the symbol
475 @code{Control-X-prefix}.
478 @cindex @kbd{C-x @key{RET}}
480 @code{mule-keymap} is the global keymap used for the @kbd{C-x @key{RET}}
486 @code{ctl-x-4-map} is the global keymap used for the @kbd{C-x 4} prefix
492 @code{ctl-x-5-map} is the global keymap used for the @kbd{C-x 5} prefix
498 @code{2C-mode-map} is the global keymap used for the @kbd{C-x 6} prefix
503 @vindex vc-prefix-map
504 @code{vc-prefix-map} is the global keymap used for the @kbd{C-x v} prefix
510 @code{goto-map} is the global keymap used for the @kbd{M-g} prefix
516 @code{search-map} is the global keymap used for the @kbd{M-s} prefix
521 @vindex facemenu-keymap
522 @code{facemenu-keymap} is the global keymap used for the @kbd{M-o}
526 The other Emacs prefix keys are @kbd{C-x @@}, @kbd{C-x a i}, @kbd{C-x
527 @key{ESC}} and @kbd{@key{ESC} @key{ESC}}. They use keymaps that have
531 The keymap binding of a prefix key is used for looking up the event
532 that follows the prefix key. (It may instead be a symbol whose function
533 definition is a keymap. The effect is the same, but the symbol serves
534 as a name for the prefix key.) Thus, the binding of @kbd{C-x} is the
535 symbol @code{Control-X-prefix}, whose function cell holds the keymap
536 for @kbd{C-x} commands. (The same keymap is also the value of
539 Prefix key definitions can appear in any active keymap. The
540 definitions of @kbd{C-c}, @kbd{C-x}, @kbd{C-h} and @key{ESC} as prefix
541 keys appear in the global map, so these prefix keys are always
542 available. Major and minor modes can redefine a key as a prefix by
543 putting a prefix key definition for it in the local map or the minor
544 mode's map. @xref{Active Keymaps}.
546 If a key is defined as a prefix in more than one active map, then its
547 various definitions are in effect merged: the commands defined in the
548 minor mode keymaps come first, followed by those in the local map's
549 prefix definition, and then by those from the global map.
551 In the following example, we make @kbd{C-p} a prefix key in the local
552 keymap, in such a way that @kbd{C-p} is identical to @kbd{C-x}. Then
553 the binding for @kbd{C-p C-f} is the function @code{find-file}, just
554 like @kbd{C-x C-f}. The key sequence @kbd{C-p 6} is not found in any
559 (use-local-map (make-sparse-keymap))
563 (local-set-key "\C-p" ctl-x-map)
567 (key-binding "\C-p\C-f")
572 (key-binding "\C-p6")
577 @defun define-prefix-command symbol &optional mapvar prompt
578 @cindex prefix command
579 @anchor{Definition of define-prefix-command}
580 This function prepares @var{symbol} for use as a prefix key's binding:
581 it creates a sparse keymap and stores it as @var{symbol}'s function
582 definition. Subsequently binding a key sequence to @var{symbol} will
583 make that key sequence into a prefix key. The return value is @code{symbol}.
585 This function also sets @var{symbol} as a variable, with the keymap as
586 its value. But if @var{mapvar} is non-@code{nil}, it sets @var{mapvar}
587 as a variable instead.
589 If @var{prompt} is non-@code{nil}, that becomes the overall prompt
590 string for the keymap. The prompt string should be given for menu keymaps
591 (@pxref{Defining Menus}).
595 @section Active Keymaps
596 @cindex active keymap
597 @cindex global keymap
600 Emacs normally contains many keymaps; at any given time, just a few
601 of them are @dfn{active}, meaning that they participate in the
602 interpretation of user input. All the active keymaps are used
603 together to determine what command to execute when a key is entered.
605 Normally the active keymaps are the @code{keymap} property keymap,
606 the keymaps of any enabled minor modes, the current buffer's local
607 keymap, and the global keymap, in that order. Emacs searches for each
608 input key sequence in all these keymaps. @xref{Searching Keymaps},
609 for more details of this procedure.
611 When the key sequence starts with a mouse event (optionally preceded
612 by a symbolic prefix), the active keymaps are determined based on the
613 position in that event. If the event happened on a string embedded
614 with a @code{display}, @code{before-string}, or @code{after-string}
615 property (@pxref{Special Properties}), the non-@code{nil} map
616 properties of the string override those of the buffer (if the
617 underlying buffer text contains map properties in its text properties
618 or overlays, they are ignored).
620 The @dfn{global keymap} holds the bindings of keys that are defined
621 regardless of the current buffer, such as @kbd{C-f}. The variable
622 @code{global-map} holds this keymap, which is always active.
624 Each buffer may have another keymap, its @dfn{local keymap}, which
625 may contain new or overriding definitions for keys. The current
626 buffer's local keymap is always active except when
627 @code{overriding-local-map} overrides it. The @code{local-map} text
628 or overlay property can specify an alternative local keymap for certain
629 parts of the buffer; see @ref{Special Properties}.
631 Each minor mode can have a keymap; if it does, the keymap is active
632 when the minor mode is enabled. Modes for emulation can specify
633 additional active keymaps through the variable
634 @code{emulation-mode-map-alists}.
636 The highest precedence normal keymap comes from the @code{keymap}
637 text or overlay property. If that is non-@code{nil}, it is the first
638 keymap to be processed, in normal circumstances.
640 However, there are also special ways for programs to substitute
641 other keymaps for some of those. The variable
642 @code{overriding-local-map}, if non-@code{nil}, specifies a keymap
643 that replaces all the usual active keymaps except the global keymap.
644 Another way to do this is with @code{overriding-terminal-local-map};
645 it operates on a per-terminal basis. These variables are documented
648 @cindex major mode keymap
649 Since every buffer that uses the same major mode normally uses the
650 same local keymap, you can think of the keymap as local to the mode. A
651 change to the local keymap of a buffer (using @code{local-set-key}, for
652 example) is seen also in the other buffers that share that keymap.
654 The local keymaps that are used for Lisp mode and some other major
655 modes exist even if they have not yet been used. These local keymaps are
656 the values of variables such as @code{lisp-mode-map}. For most major
657 modes, which are less frequently used, the local keymap is constructed
658 only when the mode is used for the first time in a session.
660 The minibuffer has local keymaps, too; they contain various completion
661 and exit commands. @xref{Intro to Minibuffers}.
663 Emacs has other keymaps that are used in a different way---translating
664 events within @code{read-key-sequence}. @xref{Translation Keymaps}.
666 @xref{Standard Keymaps}, for a list of standard keymaps.
668 @defun current-active-maps &optional olp position
669 This returns the list of active keymaps that would be used by the
670 command loop in the current circumstances to look up a key sequence.
671 Normally it ignores @code{overriding-local-map} and
672 @code{overriding-terminal-local-map}, but if @var{olp} is non-@code{nil}
673 then it pays attention to them. @var{position} can optionally be either
674 an event position as returned by @code{event-start} or a buffer
675 position, and may change the keymaps as described for
679 @defun key-binding key &optional accept-defaults no-remap position
680 This function returns the binding for @var{key} according to the
681 current active keymaps. The result is @code{nil} if @var{key} is
682 undefined in the keymaps.
684 The argument @var{accept-defaults} controls checking for default
685 bindings, as in @code{lookup-key} (@pxref{Functions for Key Lookup}).
687 When commands are remapped (@pxref{Remapping Commands}),
688 @code{key-binding} normally processes command remappings so as to
689 returns the remapped command that will actually be executed. However,
690 if @var{no-remap} is non-@code{nil}, @code{key-binding} ignores
691 remappings and returns the binding directly specified for @var{key}.
693 If @var{key} starts with a mouse event (perhaps following a prefix
694 event), the maps to be consulted are determined based on the event's
695 position. Otherwise, they are determined based on the value of point.
696 However, you can override either of them by specifying @var{position}.
697 If @var{position} is non-@code{nil}, it should be either a buffer
698 position or an event position like the value of @code{event-start}.
699 Then the maps consulted are determined based on @var{position}.
701 An error is signaled if @var{key} is not a string or a vector.
705 (key-binding "\C-x\C-f")
711 @node Searching Keymaps
712 @section Searching the Active Keymaps
713 @cindex searching active keymaps for keys
715 After translation of event subsequences (@pxref{Translation
716 Keymaps}) Emacs looks for them in the active keymaps. Here is a
717 pseudo-Lisp description of the order and conditions for searching
721 (or (if overriding-terminal-local-map
722 (@var{find-in} overriding-terminal-local-map)
723 (if overriding-local-map
724 (@var{find-in} overriding-local-map)
725 (or (@var{find-in} (get-char-property (point) 'keymap))
726 (@var{find-in-any} emulation-mode-map-alists)
727 (@var{find-in-any} minor-mode-overriding-map-alist)
728 (@var{find-in-any} minor-mode-map-alist)
729 (if (get-text-property (point) 'local-map)
730 (@var{find-in} (get-char-property (point) 'local-map))
731 (@var{find-in} (current-local-map))))))
732 (@var{find-in} (current-global-map)))
736 The @var{find-in} and @var{find-in-any} are pseudo functions that
737 search in one keymap and in an alist of keymaps, respectively.
738 (Searching a single keymap for a binding is called @dfn{key lookup};
739 see @ref{Key Lookup}.) If the key sequence starts with a mouse event,
740 or a symbolic prefix event followed by a mouse event, that event's
741 position is used instead of point and the current buffer. Mouse
742 events on an embedded string use non-@code{nil} text properties from
743 that string instead of the buffer.
747 The function finally found may be remapped
748 (@pxref{Remapping Commands}).
751 Characters that are bound to @code{self-insert-command} are translated
752 according to @code{translation-table-for-input} before insertion.
755 @code{current-active-maps} returns a list of the
756 currently active keymaps at point.
759 When a match is found (@pxref{Key Lookup}), if the binding in the
760 keymap is a function, the search is over. However if the keymap entry
761 is a symbol with a value or a string, Emacs replaces the input key
762 sequences with the variable's value or the string, and restarts the
763 search of the active keymaps.
766 @node Controlling Active Maps
767 @section Controlling the Active Keymaps
770 This variable contains the default global keymap that maps Emacs
771 keyboard input to commands. The global keymap is normally this
772 keymap. The default global keymap is a full keymap that binds
773 @code{self-insert-command} to all of the printing characters.
775 It is normal practice to change the bindings in the global keymap, but you
776 should not assign this variable any value other than the keymap it starts
780 @defun current-global-map
781 This function returns the current global keymap. This is the same as
782 the value of @code{global-map} unless you change one or the other.
783 The return value is a reference, not a copy; if you use
784 @code{define-key} or other functions on it you will alter global
790 @result{} (keymap [set-mark-command beginning-of-line @dots{}
791 delete-backward-char])
796 @defun current-local-map
797 This function returns the current buffer's local keymap, or @code{nil}
798 if it has none. In the following example, the keymap for the
799 @samp{*scratch*} buffer (using Lisp Interaction mode) is a sparse keymap
800 in which the entry for @key{ESC}, @acronym{ASCII} code 27, is another sparse
807 (10 . eval-print-last-sexp)
808 (9 . lisp-indent-line)
809 (127 . backward-delete-char-untabify)
819 @code{current-local-map} returns a reference to the local keymap, not
820 a copy of it; if you use @code{define-key} or other functions on it
821 you will alter local bindings.
823 @defun current-minor-mode-maps
824 This function returns a list of the keymaps of currently enabled minor modes.
827 @defun use-global-map keymap
828 This function makes @var{keymap} the new current global keymap. It
831 It is very unusual to change the global keymap.
834 @defun use-local-map keymap
835 This function makes @var{keymap} the new local keymap of the current
836 buffer. If @var{keymap} is @code{nil}, then the buffer has no local
837 keymap. @code{use-local-map} returns @code{nil}. Most major mode
838 commands use this function.
842 @defvar minor-mode-map-alist
843 @anchor{Definition of minor-mode-map-alist}
844 This variable is an alist describing keymaps that may or may not be
845 active according to the values of certain variables. Its elements look
849 (@var{variable} . @var{keymap})
852 The keymap @var{keymap} is active whenever @var{variable} has a
853 non-@code{nil} value. Typically @var{variable} is the variable that
854 enables or disables a minor mode. @xref{Keymaps and Minor Modes}.
856 Note that elements of @code{minor-mode-map-alist} do not have the same
857 structure as elements of @code{minor-mode-alist}. The map must be the
858 @sc{cdr} of the element; a list with the map as the second element will
859 not do. The @sc{cdr} can be either a keymap (a list) or a symbol whose
860 function definition is a keymap.
862 When more than one minor mode keymap is active, the earlier one in
863 @code{minor-mode-map-alist} takes priority. But you should design
864 minor modes so that they don't interfere with each other. If you do
865 this properly, the order will not matter.
867 See @ref{Keymaps and Minor Modes}, for more information about minor
868 modes. See also @code{minor-mode-key-binding} (@pxref{Functions for Key
872 @defvar minor-mode-overriding-map-alist
873 This variable allows major modes to override the key bindings for
874 particular minor modes. The elements of this alist look like the
875 elements of @code{minor-mode-map-alist}: @code{(@var{variable}
878 If a variable appears as an element of
879 @code{minor-mode-overriding-map-alist}, the map specified by that
880 element totally replaces any map specified for the same variable in
881 @code{minor-mode-map-alist}.
883 @code{minor-mode-overriding-map-alist} is automatically buffer-local in
887 @defvar overriding-local-map
888 If non-@code{nil}, this variable holds a keymap to use instead of the
889 buffer's local keymap, any text property or overlay keymaps, and any
890 minor mode keymaps. This keymap, if specified, overrides all other
891 maps that would have been active, except for the current global map.
894 @defvar overriding-terminal-local-map
895 If non-@code{nil}, this variable holds a keymap to use instead of
896 @code{overriding-local-map}, the buffer's local keymap, text property
897 or overlay keymaps, and all the minor mode keymaps.
899 This variable is always local to the current terminal and cannot be
900 buffer-local. @xref{Multiple Terminals}. It is used to implement
901 incremental search mode.
904 @defvar overriding-local-map-menu-flag
905 If this variable is non-@code{nil}, the value of
906 @code{overriding-local-map} or @code{overriding-terminal-local-map} can
907 affect the display of the menu bar. The default value is @code{nil}, so
908 those map variables have no effect on the menu bar.
910 Note that these two map variables do affect the execution of key
911 sequences entered using the menu bar, even if they do not affect the
912 menu bar display. So if a menu bar key sequence comes in, you should
913 clear the variables before looking up and executing that key sequence.
914 Modes that use the variables would typically do this anyway; normally
915 they respond to events that they do not handle by ``unreading'' them and
919 @defvar special-event-map
920 This variable holds a keymap for special events. If an event type has a
921 binding in this keymap, then it is special, and the binding for the
922 event is run directly by @code{read-event}. @xref{Special Events}.
925 @defvar emulation-mode-map-alists
926 This variable holds a list of keymap alists to use for emulations
927 modes. It is intended for modes or packages using multiple minor-mode
928 keymaps. Each element is a keymap alist which has the same format and
929 meaning as @code{minor-mode-map-alist}, or a symbol with a variable
930 binding which is such an alist. The ``active'' keymaps in each alist
931 are used before @code{minor-mode-map-alist} and
932 @code{minor-mode-overriding-map-alist}.
940 @dfn{Key lookup} is the process of finding the binding of a key
941 sequence from a given keymap. The execution or use of the binding is
942 not part of key lookup.
944 Key lookup uses just the event type of each event in the key sequence;
945 the rest of the event is ignored. In fact, a key sequence used for key
946 lookup may designate a mouse event with just its types (a symbol)
947 instead of the entire event (a list). @xref{Input Events}. Such
948 a ``key sequence'' is insufficient for @code{command-execute} to run,
949 but it is sufficient for looking up or rebinding a key.
951 When the key sequence consists of multiple events, key lookup
952 processes the events sequentially: the binding of the first event is
953 found, and must be a keymap; then the second event's binding is found in
954 that keymap, and so on until all the events in the key sequence are used
955 up. (The binding thus found for the last event may or may not be a
956 keymap.) Thus, the process of key lookup is defined in terms of a
957 simpler process for looking up a single event in a keymap. How that is
958 done depends on the type of object associated with the event in that
961 Let's use the term @dfn{keymap entry} to describe the value found by
962 looking up an event type in a keymap. (This doesn't include the item
963 string and other extra elements in a keymap element for a menu item, because
964 @code{lookup-key} and other key lookup functions don't include them in
965 the returned value.) While any Lisp object may be stored in a keymap
966 as a keymap entry, not all make sense for key lookup. Here is a table
967 of the meaningful types of keymap entries:
971 @cindex @code{nil} in keymap
972 @code{nil} means that the events used so far in the lookup form an
973 undefined key. When a keymap fails to mention an event type at all, and
974 has no default binding, that is equivalent to a binding of @code{nil}
978 @cindex command in keymap
979 The events used so far in the lookup form a complete key,
980 and @var{command} is its binding. @xref{What Is a Function}.
983 @cindex string in keymap
984 The array (either a string or a vector) is a keyboard macro. The events
985 used so far in the lookup form a complete key, and the array is its
986 binding. See @ref{Keyboard Macros}, for more information.
989 @cindex keymap in keymap
990 The events used so far in the lookup form a prefix key. The next
991 event of the key sequence is looked up in @var{keymap}.
994 @cindex list in keymap
995 The meaning of a list depends on what it contains:
999 If the @sc{car} of @var{list} is the symbol @code{keymap}, then the list
1000 is a keymap, and is treated as a keymap (see above).
1003 @cindex @code{lambda} in keymap
1004 If the @sc{car} of @var{list} is @code{lambda}, then the list is a
1005 lambda expression. This is presumed to be a function, and is treated
1006 as such (see above). In order to execute properly as a key binding,
1007 this function must be a command---it must have an @code{interactive}
1008 specification. @xref{Defining Commands}.
1011 If the @sc{car} of @var{list} is a keymap and the @sc{cdr} is an event
1012 type, then this is an @dfn{indirect entry}:
1015 (@var{othermap} . @var{othertype})
1018 When key lookup encounters an indirect entry, it looks up instead the
1019 binding of @var{othertype} in @var{othermap} and uses that.
1021 This feature permits you to define one key as an alias for another key.
1022 For example, an entry whose @sc{car} is the keymap called @code{esc-map}
1023 and whose @sc{cdr} is 32 (the code for @key{SPC}) means, ``Use the global
1024 binding of @kbd{Meta-@key{SPC}}, whatever that may be.''
1028 @cindex symbol in keymap
1029 The function definition of @var{symbol} is used in place of
1030 @var{symbol}. If that too is a symbol, then this process is repeated,
1031 any number of times. Ultimately this should lead to an object that is
1032 a keymap, a command, or a keyboard macro. A list is allowed if it is a
1033 keymap or a command, but indirect entries are not understood when found
1036 Note that keymaps and keyboard macros (strings and vectors) are not
1037 valid functions, so a symbol with a keymap, string, or vector as its
1038 function definition is invalid as a function. It is, however, valid as
1039 a key binding. If the definition is a keyboard macro, then the symbol
1040 is also valid as an argument to @code{command-execute}
1041 (@pxref{Interactive Call}).
1043 @cindex @code{undefined} in keymap
1044 The symbol @code{undefined} is worth special mention: it means to treat
1045 the key as undefined. Strictly speaking, the key is defined, and its
1046 binding is the command @code{undefined}; but that command does the same
1047 thing that is done automatically for an undefined key: it rings the bell
1048 (by calling @code{ding}) but does not signal an error.
1050 @cindex preventing prefix key
1051 @code{undefined} is used in local keymaps to override a global key
1052 binding and make the key ``undefined'' locally. A local binding of
1053 @code{nil} would fail to do this because it would not override the
1056 @item @var{anything else}
1057 If any other type of object is found, the events used so far in the
1058 lookup form a complete key, and the object is its binding, but the
1059 binding is not executable as a command.
1062 In short, a keymap entry may be a keymap, a command, a keyboard macro,
1063 a symbol that leads to one of them, or an indirection or @code{nil}.
1064 Here is an example of a sparse keymap with two characters bound to
1065 commands and one bound to another keymap. This map is the normal value
1066 of @code{emacs-lisp-mode-map}. Note that 9 is the code for @key{TAB},
1067 127 for @key{DEL}, 27 for @key{ESC}, 17 for @kbd{C-q} and 24 for
1072 (keymap (9 . lisp-indent-line)
1073 (127 . backward-delete-char-untabify)
1074 (27 keymap (17 . indent-sexp) (24 . eval-defun)))
1078 @node Functions for Key Lookup
1079 @section Functions for Key Lookup
1081 Here are the functions and variables pertaining to key lookup.
1083 @defun lookup-key keymap key &optional accept-defaults
1084 This function returns the definition of @var{key} in @var{keymap}. All
1085 the other functions described in this chapter that look up keys use
1086 @code{lookup-key}. Here are examples:
1090 (lookup-key (current-global-map) "\C-x\C-f")
1094 (lookup-key (current-global-map) (kbd "C-x C-f"))
1098 (lookup-key (current-global-map) "\C-x\C-f12345")
1103 If the string or vector @var{key} is not a valid key sequence according
1104 to the prefix keys specified in @var{keymap}, it must be ``too long''
1105 and have extra events at the end that do not fit into a single key
1106 sequence. Then the value is a number, the number of events at the front
1107 of @var{key} that compose a complete key.
1110 If @var{accept-defaults} is non-@code{nil}, then @code{lookup-key}
1111 considers default bindings as well as bindings for the specific events
1112 in @var{key}. Otherwise, @code{lookup-key} reports only bindings for
1113 the specific sequence @var{key}, ignoring default bindings except when
1114 you explicitly ask about them. (To do this, supply @code{t} as an
1115 element of @var{key}; see @ref{Format of Keymaps}.)
1117 If @var{key} contains a meta character (not a function key), that
1118 character is implicitly replaced by a two-character sequence: the value
1119 of @code{meta-prefix-char}, followed by the corresponding non-meta
1120 character. Thus, the first example below is handled by conversion into
1125 (lookup-key (current-global-map) "\M-f")
1126 @result{} forward-word
1129 (lookup-key (current-global-map) "\ef")
1130 @result{} forward-word
1134 Unlike @code{read-key-sequence}, this function does not modify the
1135 specified events in ways that discard information (@pxref{Key Sequence
1136 Input}). In particular, it does not convert letters to lower case and
1137 it does not change drag events to clicks.
1140 @deffn Command undefined
1141 Used in keymaps to undefine keys. It calls @code{ding}, but does
1145 @defun local-key-binding key &optional accept-defaults
1146 This function returns the binding for @var{key} in the current
1147 local keymap, or @code{nil} if it is undefined there.
1150 The argument @var{accept-defaults} controls checking for default bindings,
1151 as in @code{lookup-key} (above).
1154 @defun global-key-binding key &optional accept-defaults
1155 This function returns the binding for command @var{key} in the
1156 current global keymap, or @code{nil} if it is undefined there.
1159 The argument @var{accept-defaults} controls checking for default bindings,
1160 as in @code{lookup-key} (above).
1164 @defun minor-mode-key-binding key &optional accept-defaults
1165 This function returns a list of all the active minor mode bindings of
1166 @var{key}. More precisely, it returns an alist of pairs
1167 @code{(@var{modename} . @var{binding})}, where @var{modename} is the
1168 variable that enables the minor mode, and @var{binding} is @var{key}'s
1169 binding in that mode. If @var{key} has no minor-mode bindings, the
1170 value is @code{nil}.
1172 If the first binding found is not a prefix definition (a keymap or a
1173 symbol defined as a keymap), all subsequent bindings from other minor
1174 modes are omitted, since they would be completely shadowed. Similarly,
1175 the list omits non-prefix bindings that follow prefix bindings.
1177 The argument @var{accept-defaults} controls checking for default
1178 bindings, as in @code{lookup-key} (above).
1181 @defopt meta-prefix-char
1183 This variable is the meta-prefix character code. It is used for
1184 translating a meta character to a two-character sequence so it can be
1185 looked up in a keymap. For useful results, the value should be a
1186 prefix event (@pxref{Prefix Keys}). The default value is 27, which is
1187 the @acronym{ASCII} code for @key{ESC}.
1189 As long as the value of @code{meta-prefix-char} remains 27, key lookup
1190 translates @kbd{M-b} into @kbd{@key{ESC} b}, which is normally defined
1191 as the @code{backward-word} command. However, if you were to set
1192 @code{meta-prefix-char} to 24, the code for @kbd{C-x}, then Emacs will
1193 translate @kbd{M-b} into @kbd{C-x b}, whose standard binding is the
1194 @code{switch-to-buffer} command. (Don't actually do this!) Here is an
1195 illustration of what would happen:
1199 meta-prefix-char ; @r{The default value.}
1203 (key-binding "\M-b")
1204 @result{} backward-word
1207 ?\C-x ; @r{The print representation}
1208 @result{} 24 ; @r{of a character.}
1211 (setq meta-prefix-char 24)
1215 (key-binding "\M-b")
1216 @result{} switch-to-buffer ; @r{Now, typing @kbd{M-b} is}
1217 ; @r{like typing @kbd{C-x b}.}
1219 (setq meta-prefix-char 27) ; @r{Avoid confusion!}
1220 @result{} 27 ; @r{Restore the default value!}
1224 This translation of one event into two happens only for characters, not
1225 for other kinds of input events. Thus, @kbd{M-@key{F1}}, a function
1226 key, is not converted into @kbd{@key{ESC} @key{F1}}.
1229 @node Changing Key Bindings
1230 @section Changing Key Bindings
1231 @cindex changing key bindings
1234 The way to rebind a key is to change its entry in a keymap. If you
1235 change a binding in the global keymap, the change is effective in all
1236 buffers (though it has no direct effect in buffers that shadow the
1237 global binding with a local one). If you change the current buffer's
1238 local map, that usually affects all buffers using the same major mode.
1239 The @code{global-set-key} and @code{local-set-key} functions are
1240 convenient interfaces for these operations (@pxref{Key Binding
1241 Commands}). You can also use @code{define-key}, a more general
1242 function; then you must specify explicitly the map to change.
1244 When choosing the key sequences for Lisp programs to rebind, please
1245 follow the Emacs conventions for use of various keys (@pxref{Key
1246 Binding Conventions}).
1248 @cindex meta character key constants
1249 @cindex control character key constants
1250 In writing the key sequence to rebind, it is good to use the special
1251 escape sequences for control and meta characters (@pxref{String Type}).
1252 The syntax @samp{\C-} means that the following character is a control
1253 character and @samp{\M-} means that the following character is a meta
1254 character. Thus, the string @code{"\M-x"} is read as containing a
1255 single @kbd{M-x}, @code{"\C-f"} is read as containing a single
1256 @kbd{C-f}, and @code{"\M-\C-x"} and @code{"\C-\M-x"} are both read as
1257 containing a single @kbd{C-M-x}. You can also use this escape syntax in
1258 vectors, as well as others that aren't allowed in strings; one example
1259 is @samp{[?\C-\H-x home]}. @xref{Character Type}.
1261 The key definition and lookup functions accept an alternate syntax for
1262 event types in a key sequence that is a vector: you can use a list
1263 containing modifier names plus one base event (a character or function
1264 key name). For example, @code{(control ?a)} is equivalent to
1265 @code{?\C-a} and @code{(hyper control left)} is equivalent to
1266 @code{C-H-left}. One advantage of such lists is that the precise
1267 numeric codes for the modifier bits don't appear in compiled files.
1269 The functions below signal an error if @var{keymap} is not a keymap,
1270 or if @var{key} is not a string or vector representing a key sequence.
1271 You can use event types (symbols) as shorthand for events that are
1272 lists. The @code{kbd} macro (@pxref{Key Sequences}) is a convenient
1273 way to specify the key sequence.
1275 @defun define-key keymap key binding
1276 This function sets the binding for @var{key} in @var{keymap}. (If
1277 @var{key} is more than one event long, the change is actually made
1278 in another keymap reached from @var{keymap}.) The argument
1279 @var{binding} can be any Lisp object, but only certain types are
1280 meaningful. (For a list of meaningful types, see @ref{Key Lookup}.)
1281 The value returned by @code{define-key} is @var{binding}.
1283 If @var{key} is @code{[t]}, this sets the default binding in
1284 @var{keymap}. When an event has no binding of its own, the Emacs
1285 command loop uses the keymap's default binding, if there is one.
1287 @cindex invalid prefix key error
1288 @cindex key sequence error
1289 Every prefix of @var{key} must be a prefix key (i.e., bound to a keymap)
1290 or undefined; otherwise an error is signaled. If some prefix of
1291 @var{key} is undefined, then @code{define-key} defines it as a prefix
1292 key so that the rest of @var{key} can be defined as specified.
1294 If there was previously no binding for @var{key} in @var{keymap}, the
1295 new binding is added at the beginning of @var{keymap}. The order of
1296 bindings in a keymap makes no difference for keyboard input, but it
1297 does matter for menu keymaps (@pxref{Menu Keymaps}).
1300 This example creates a sparse keymap and makes a number of
1305 (setq map (make-sparse-keymap))
1309 (define-key map "\C-f" 'forward-char)
1310 @result{} forward-char
1314 @result{} (keymap (6 . forward-char))
1318 ;; @r{Build sparse submap for @kbd{C-x} and bind @kbd{f} in that.}
1319 (define-key map (kbd "C-x f") 'forward-word)
1320 @result{} forward-word
1325 (24 keymap ; @kbd{C-x}
1326 (102 . forward-word)) ; @kbd{f}
1327 (6 . forward-char)) ; @kbd{C-f}
1331 ;; @r{Bind @kbd{C-p} to the @code{ctl-x-map}.}
1332 (define-key map (kbd "C-p") ctl-x-map)
1334 @result{} [nil @dots{} find-file @dots{} backward-kill-sentence]
1338 ;; @r{Bind @kbd{C-f} to @code{foo} in the @code{ctl-x-map}.}
1339 (define-key map (kbd "C-p C-f") 'foo)
1344 @result{} (keymap ; @r{Note @code{foo} in @code{ctl-x-map}.}
1345 (16 keymap [nil @dots{} foo @dots{} backward-kill-sentence])
1347 (102 . forward-word))
1353 Note that storing a new binding for @kbd{C-p C-f} actually works by
1354 changing an entry in @code{ctl-x-map}, and this has the effect of
1355 changing the bindings of both @kbd{C-p C-f} and @kbd{C-x C-f} in the
1358 The function @code{substitute-key-definition} scans a keymap for
1359 keys that have a certain binding and rebinds them with a different
1360 binding. Another feature which is cleaner and can often produce the
1361 same results to remap one command into another (@pxref{Remapping
1364 @defun substitute-key-definition olddef newdef keymap &optional oldmap
1365 @cindex replace bindings
1366 This function replaces @var{olddef} with @var{newdef} for any keys in
1367 @var{keymap} that were bound to @var{olddef}. In other words,
1368 @var{olddef} is replaced with @var{newdef} wherever it appears. The
1369 function returns @code{nil}.
1371 For example, this redefines @kbd{C-x C-f}, if you do it in an Emacs with
1376 (substitute-key-definition
1377 'find-file 'find-file-read-only (current-global-map))
1382 If @var{oldmap} is non-@code{nil}, that changes the behavior of
1383 @code{substitute-key-definition}: the bindings in @var{oldmap} determine
1384 which keys to rebind. The rebindings still happen in @var{keymap}, not
1385 in @var{oldmap}. Thus, you can change one map under the control of the
1386 bindings in another. For example,
1389 (substitute-key-definition
1390 'delete-backward-char 'my-funny-delete
1395 puts the special deletion command in @code{my-map} for whichever keys
1396 are globally bound to the standard deletion command.
1398 Here is an example showing a keymap before and after substitution:
1406 @result{} (keymap (49 . olddef-1) (50 . olddef-2) (51 . olddef-1))
1410 (substitute-key-definition 'olddef-1 'newdef map)
1415 @result{} (keymap (49 . newdef) (50 . olddef-2) (51 . newdef))
1420 @defun suppress-keymap keymap &optional nodigits
1421 @cindex @code{self-insert-command} override
1422 This function changes the contents of the full keymap @var{keymap} by
1423 remapping @code{self-insert-command} to the command @code{undefined}
1424 (@pxref{Remapping Commands}). This has the effect of undefining all
1425 printing characters, thus making ordinary insertion of text impossible.
1426 @code{suppress-keymap} returns @code{nil}.
1428 If @var{nodigits} is @code{nil}, then @code{suppress-keymap} defines
1429 digits to run @code{digit-argument}, and @kbd{-} to run
1430 @code{negative-argument}. Otherwise it makes them undefined like the
1431 rest of the printing characters.
1433 @cindex yank suppression
1434 @cindex @code{quoted-insert} suppression
1435 The @code{suppress-keymap} function does not make it impossible to
1436 modify a buffer, as it does not suppress commands such as @code{yank}
1437 and @code{quoted-insert}. To prevent any modification of a buffer, make
1438 it read-only (@pxref{Read Only Buffers}).
1440 Since this function modifies @var{keymap}, you would normally use it
1441 on a newly created keymap. Operating on an existing keymap
1442 that is used for some other purpose is likely to cause trouble; for
1443 example, suppressing @code{global-map} would make it impossible to use
1446 Most often, @code{suppress-keymap} is used to initialize local
1447 keymaps of modes such as Rmail and Dired where insertion of text is not
1448 desirable and the buffer is read-only. Here is an example taken from
1449 the file @file{emacs/lisp/dired.el}, showing how the local keymap for
1450 Dired mode is set up:
1454 (setq dired-mode-map (make-keymap))
1455 (suppress-keymap dired-mode-map)
1456 (define-key dired-mode-map "r" 'dired-rename-file)
1457 (define-key dired-mode-map "\C-d" 'dired-flag-file-deleted)
1458 (define-key dired-mode-map "d" 'dired-flag-file-deleted)
1459 (define-key dired-mode-map "v" 'dired-view-file)
1460 (define-key dired-mode-map "e" 'dired-find-file)
1461 (define-key dired-mode-map "f" 'dired-find-file)
1467 @node Remapping Commands
1468 @section Remapping Commands
1469 @cindex remapping commands
1471 A special kind of key binding, using a special ``key sequence''
1472 which includes a command name, has the effect of @dfn{remapping} that
1473 command into another. Here's how it works. You make a key binding
1474 for a key sequence that starts with the dummy event @code{remap},
1475 followed by the command name you want to remap. Specify the remapped
1476 definition as the definition in this binding. The remapped definition
1477 is usually a command name, but it can be any valid definition for
1480 Here's an example. Suppose that My mode uses special commands
1481 @code{my-kill-line} and @code{my-kill-word}, which should be invoked
1482 instead of @code{kill-line} and @code{kill-word}. It can establish
1483 this by making these two command-remapping bindings in its keymap:
1486 (define-key my-mode-map [remap kill-line] 'my-kill-line)
1487 (define-key my-mode-map [remap kill-word] 'my-kill-word)
1490 Whenever @code{my-mode-map} is an active keymap, if the user types
1491 @kbd{C-k}, Emacs will find the standard global binding of
1492 @code{kill-line} (assuming nobody has changed it). But
1493 @code{my-mode-map} remaps @code{kill-line} to @code{my-kill-line},
1494 so instead of running @code{kill-line}, Emacs runs
1495 @code{my-kill-line}.
1497 Remapping only works through a single level. In other words,
1500 (define-key my-mode-map [remap kill-line] 'my-kill-line)
1501 (define-key my-mode-map [remap my-kill-line] 'my-other-kill-line)
1505 does not have the effect of remapping @code{kill-line} into
1506 @code{my-other-kill-line}. If an ordinary key binding specifies
1507 @code{kill-line}, this keymap will remap it to @code{my-kill-line};
1508 if an ordinary binding specifies @code{my-kill-line}, this keymap will
1509 remap it to @code{my-other-kill-line}.
1511 @defun command-remapping command &optional position keymaps
1512 This function returns the remapping for @var{command} (a symbol),
1513 given the current active keymaps. If @var{command} is not remapped
1514 (which is the usual situation), or not a symbol, the function returns
1515 @code{nil}. @code{position} can optionally specify a buffer position
1516 or an event position to determine the keymaps to use, as in
1519 If the optional argument @code{keymaps} is non-@code{nil}, it
1520 specifies a list of keymaps to search in. This argument is ignored if
1521 @code{position} is non-@code{nil}.
1524 @node Translation Keymaps
1525 @section Keymaps for Translating Sequences of Events
1526 @cindex keymaps for translating events
1528 This section describes keymaps that are used during reading a key
1529 sequence, to translate certain event sequences into others.
1530 @code{read-key-sequence} checks every subsequence of the key sequence
1531 being read, as it is read, against @code{input-decode-map}, then
1532 @code{local-function-key-map}, and then against @code{key-translation-map}.
1534 @defvar input-decode-map
1535 This variable holds a keymap that describes the character sequences sent
1536 by function keys on an ordinary character terminal. This keymap has the
1537 same structure as other keymaps, but is used differently: it specifies
1538 translations to make while reading key sequences, rather than bindings
1541 If @code{input-decode-map} ``binds'' a key sequence @var{k} to a vector
1542 @var{v}, then when @var{k} appears as a subsequence @emph{anywhere} in a
1543 key sequence, it is replaced with the events in @var{v}.
1545 For example, VT100 terminals send @kbd{@key{ESC} O P} when the
1546 keypad @key{PF1} key is pressed. Therefore, we want Emacs to translate
1547 that sequence of events into the single event @code{pf1}. We accomplish
1548 this by ``binding'' @kbd{@key{ESC} O P} to @code{[pf1]} in
1549 @code{input-decode-map}, when using a VT100.
1551 Thus, typing @kbd{C-c @key{PF1}} sends the character sequence @kbd{C-c
1552 @key{ESC} O P}; later the function @code{read-key-sequence} translates
1553 this back into @kbd{C-c @key{PF1}}, which it returns as the vector
1556 The value of @code{input-decode-map} is usually set up automatically
1557 according to the terminal's Terminfo or Termcap entry, but sometimes
1558 those need help from terminal-specific Lisp files. Emacs comes with
1559 terminal-specific files for many common terminals; their main purpose is
1560 to make entries in @code{input-decode-map} beyond those that can be
1561 deduced from Termcap and Terminfo. @xref{Terminal-Specific}.
1564 @defvar local-function-key-map
1565 This variable holds a keymap similar to @code{input-decode-map} except
1566 that it describes key sequences which should be translated to
1567 alternative interpretations that are usually preferred. It applies
1568 after @code{input-decode-map} and before @code{key-translation-map}.
1570 Entries in @code{local-function-key-map} are ignored if they conflict
1571 with bindings made in the minor mode, local, or global keymaps. I.e.
1572 the remapping only applies if the original key sequence would
1573 otherwise not have any binding.
1575 @code{local-function-key-map} inherits from @code{function-key-map},
1576 but the latter should not be used directly.
1579 @defvar key-translation-map
1580 This variable is another keymap used just like @code{input-decode-map}
1581 to translate input events into other events. It differs from
1582 @code{input-decode-map} in that it goes to work after
1583 @code{local-function-key-map} is finished rather than before; it
1584 receives the results of translation by @code{local-function-key-map}.
1586 Just like @code{input-decode-map}, but unlike
1587 @code{local-function-key-map}, this keymap is applied regardless of
1588 whether the input key-sequence has a normal binding. Note however
1589 that actual key bindings can have an effect on
1590 @code{key-translation-map}, even though they are overridden by it.
1591 Indeed, actual key bindings override @code{local-function-key-map} and
1592 thus may alter the key sequence that @code{key-translation-map}
1593 receives. Clearly, it is better to avoid this type of situation.
1595 The intent of @code{key-translation-map} is for users to map one
1596 character set to another, including ordinary characters normally bound
1597 to @code{self-insert-command}.
1600 @cindex key translation function
1601 You can use @code{input-decode-map}, @code{local-function-key-map}, or
1602 @code{key-translation-map} for more than simple aliases, by using a
1603 function, instead of a key sequence, as the ``translation'' of a key.
1604 Then this function is called to compute the translation of that key.
1606 The key translation function receives one argument, which is the prompt
1607 that was specified in @code{read-key-sequence}---or @code{nil} if the
1608 key sequence is being read by the editor command loop. In most cases
1609 you can ignore the prompt value.
1611 If the function reads input itself, it can have the effect of altering
1612 the event that follows. For example, here's how to define @kbd{C-c h}
1613 to turn the character that follows into a Hyper character:
1617 (defun hyperify (prompt)
1618 (let ((e (read-event)))
1619 (vector (if (numberp e)
1620 (logior (lsh 1 24) e)
1621 (if (memq 'hyper (event-modifiers e))
1623 (add-event-modifier "H-" e))))))
1625 (defun add-event-modifier (string e)
1626 (let ((symbol (if (symbolp e) e (car e))))
1627 (setq symbol (intern (concat string
1628 (symbol-name symbol))))
1633 (cons symbol (cdr e)))))
1635 (define-key local-function-key-map "\C-ch" 'hyperify)
1639 If you have enabled keyboard character set decoding using
1640 @code{set-keyboard-coding-system}, decoding is done after the
1641 translations listed above. @xref{Terminal I/O Encoding}. However, in
1642 future Emacs versions, character set decoding may be done at an
1645 @node Key Binding Commands
1646 @section Commands for Binding Keys
1648 This section describes some convenient interactive interfaces for
1649 changing key bindings. They work by calling @code{define-key}.
1651 People often use @code{global-set-key} in their init files
1652 (@pxref{Init File}) for simple customization. For example,
1655 (global-set-key (kbd "C-x C-\\") 'next-line)
1662 (global-set-key [?\C-x ?\C-\\] 'next-line)
1669 (global-set-key [(control ?x) (control ?\\)] 'next-line)
1673 redefines @kbd{C-x C-\} to move down a line.
1676 (global-set-key [M-mouse-1] 'mouse-set-point)
1680 redefines the first (leftmost) mouse button, entered with the Meta key, to
1681 set point where you click.
1683 @cindex non-@acronym{ASCII} text in keybindings
1684 Be careful when using non-@acronym{ASCII} text characters in Lisp
1685 specifications of keys to bind. If these are read as multibyte text, as
1686 they usually will be in a Lisp file (@pxref{Loading Non-ASCII}), you
1687 must type the keys as multibyte too. For instance, if you use this:
1690 (global-set-key "@"o" 'my-function) ; bind o-umlaut
1697 (global-set-key ?@"o 'my-function) ; bind o-umlaut
1701 and your language environment is multibyte Latin-1, these commands
1702 actually bind the multibyte character with code 2294, not the unibyte
1703 Latin-1 character with code 246 (@kbd{M-v}). In order to use this
1704 binding, you need to enter the multibyte Latin-1 character as keyboard
1705 input. One way to do this is by using an appropriate input method
1706 (@pxref{Input Methods, , Input Methods, emacs, The GNU Emacs Manual}).
1708 If you want to use a unibyte character in the key binding, you can
1709 construct the key sequence string using @code{multibyte-char-to-unibyte}
1710 or @code{string-make-unibyte} (@pxref{Converting Representations}).
1712 @deffn Command global-set-key key binding
1713 This function sets the binding of @var{key} in the current global map
1718 (global-set-key @var{key} @var{binding})
1720 (define-key (current-global-map) @var{key} @var{binding})
1725 @deffn Command global-unset-key key
1726 @cindex unbinding keys
1727 This function removes the binding of @var{key} from the current
1730 One use of this function is in preparation for defining a longer key
1731 that uses @var{key} as a prefix---which would not be allowed if
1732 @var{key} has a non-prefix binding. For example:
1736 (global-unset-key "\C-l")
1740 (global-set-key "\C-l\C-l" 'redraw-display)
1745 This function is implemented simply using @code{define-key}:
1749 (global-unset-key @var{key})
1751 (define-key (current-global-map) @var{key} nil)
1756 @deffn Command local-set-key key binding
1757 This function sets the binding of @var{key} in the current local
1758 keymap to @var{binding}.
1762 (local-set-key @var{key} @var{binding})
1764 (define-key (current-local-map) @var{key} @var{binding})
1769 @deffn Command local-unset-key key
1770 This function removes the binding of @var{key} from the current
1775 (local-unset-key @var{key})
1777 (define-key (current-local-map) @var{key} nil)
1782 @node Scanning Keymaps
1783 @section Scanning Keymaps
1785 This section describes functions used to scan all the current keymaps
1786 for the sake of printing help information.
1788 @defun accessible-keymaps keymap &optional prefix
1789 This function returns a list of all the keymaps that can be reached (via
1790 zero or more prefix keys) from @var{keymap}. The value is an
1791 association list with elements of the form @code{(@var{key} .@:
1792 @var{map})}, where @var{key} is a prefix key whose definition in
1793 @var{keymap} is @var{map}.
1795 The elements of the alist are ordered so that the @var{key} increases
1796 in length. The first element is always @code{([] .@: @var{keymap})},
1797 because the specified keymap is accessible from itself with a prefix of
1800 If @var{prefix} is given, it should be a prefix key sequence; then
1801 @code{accessible-keymaps} includes only the submaps whose prefixes start
1802 with @var{prefix}. These elements look just as they do in the value of
1803 @code{(accessible-keymaps)}; the only difference is that some elements
1806 In the example below, the returned alist indicates that the key
1807 @key{ESC}, which is displayed as @samp{^[}, is a prefix key whose
1808 definition is the sparse keymap @code{(keymap (83 .@: center-paragraph)
1813 (accessible-keymaps (current-local-map))
1814 @result{}(([] keymap
1815 (27 keymap ; @r{Note this keymap for @key{ESC} is repeated below.}
1816 (83 . center-paragraph)
1817 (115 . center-line))
1818 (9 . tab-to-tab-stop))
1823 (83 . center-paragraph)
1828 In the following example, @kbd{C-h} is a prefix key that uses a sparse
1829 keymap starting with @code{(keymap (118 . describe-variable)@dots{})}.
1830 Another prefix, @kbd{C-x 4}, uses a keymap which is also the value of
1831 the variable @code{ctl-x-4-map}. The event @code{mode-line} is one of
1832 several dummy events used as prefixes for mouse actions in special parts
1837 (accessible-keymaps (current-global-map))
1838 @result{} (([] keymap [set-mark-command beginning-of-line @dots{}
1839 delete-backward-char])
1842 ("^H" keymap (118 . describe-variable) @dots{}
1843 (8 . help-for-help))
1846 ("^X" keymap [x-flush-mouse-queue @dots{}
1847 backward-kill-sentence])
1850 ("^[" keymap [mark-sexp backward-sexp @dots{}
1851 backward-kill-word])
1853 ("^X4" keymap (15 . display-buffer) @dots{})
1856 (S-mouse-2 . mouse-split-window-horizontally) @dots{}))
1861 These are not all the keymaps you would see in actuality.
1864 @defun map-keymap function keymap
1865 The function @code{map-keymap} calls @var{function} once
1866 for each binding in @var{keymap}. It passes two arguments,
1867 the event type and the value of the binding. If @var{keymap}
1868 has a parent, the parent's bindings are included as well.
1869 This works recursively: if the parent has itself a parent, then the
1870 grandparent's bindings are also included and so on.
1872 This function is the cleanest way to examine all the bindings
1876 @defun where-is-internal command &optional keymap firstonly noindirect no-remap
1877 This function is a subroutine used by the @code{where-is} command
1878 (@pxref{Help, , Help, emacs,The GNU Emacs Manual}). It returns a list
1879 of all key sequences (of any length) that are bound to @var{command} in a
1882 The argument @var{command} can be any object; it is compared with all
1883 keymap entries using @code{eq}.
1885 If @var{keymap} is @code{nil}, then the maps used are the current active
1886 keymaps, disregarding @code{overriding-local-map} (that is, pretending
1887 its value is @code{nil}). If @var{keymap} is a keymap, then the
1888 maps searched are @var{keymap} and the global keymap. If @var{keymap}
1889 is a list of keymaps, only those keymaps are searched.
1891 Usually it's best to use @code{overriding-local-map} as the expression
1892 for @var{keymap}. Then @code{where-is-internal} searches precisely the
1893 keymaps that are active. To search only the global map, pass
1894 @code{(keymap)} (an empty keymap) as @var{keymap}.
1896 If @var{firstonly} is @code{non-ascii}, then the value is a single
1897 vector representing the first key sequence found, rather than a list of
1898 all possible key sequences. If @var{firstonly} is @code{t}, then the
1899 value is the first key sequence, except that key sequences consisting
1900 entirely of @acronym{ASCII} characters (or meta variants of @acronym{ASCII}
1901 characters) are preferred to all other key sequences and that the
1902 return value can never be a menu binding.
1904 If @var{noindirect} is non-@code{nil}, @code{where-is-internal} doesn't
1905 follow indirect keymap bindings. This makes it possible to search for
1906 an indirect definition itself.
1908 When command remapping is in effect (@pxref{Remapping Commands}),
1909 @code{where-is-internal} figures out when a command will be run due to
1910 remapping and reports keys accordingly. It also returns @code{nil} if
1911 @var{command} won't really be run because it has been remapped to some
1912 other command. However, if @var{no-remap} is non-@code{nil}.
1913 @code{where-is-internal} ignores remappings.
1917 (where-is-internal 'describe-function)
1918 @result{} ([8 102] [f1 102] [help 102]
1919 [menu-bar help-menu describe describe-function])
1924 @deffn Command describe-bindings &optional prefix buffer-or-name
1925 This function creates a listing of all current key bindings, and
1926 displays it in a buffer named @samp{*Help*}. The text is grouped by
1927 modes---minor modes first, then the major mode, then global bindings.
1929 If @var{prefix} is non-@code{nil}, it should be a prefix key; then the
1930 listing includes only keys that start with @var{prefix}.
1932 The listing describes meta characters as @key{ESC} followed by the
1933 corresponding non-meta character.
1935 When several characters with consecutive @acronym{ASCII} codes have the
1936 same definition, they are shown together, as
1937 @samp{@var{firstchar}..@var{lastchar}}. In this instance, you need to
1938 know the @acronym{ASCII} codes to understand which characters this means.
1939 For example, in the default global map, the characters @samp{@key{SPC}
1940 ..@: ~} are described by a single line. @key{SPC} is @acronym{ASCII} 32,
1941 @kbd{~} is @acronym{ASCII} 126, and the characters between them include all
1942 the normal printing characters, (e.g., letters, digits, punctuation,
1943 etc.@:); all these characters are bound to @code{self-insert-command}.
1945 If @var{buffer-or-name} is non-@code{nil}, it should be a buffer or a
1946 buffer name. Then @code{describe-bindings} lists that buffer's bindings,
1947 instead of the current buffer's.
1951 @section Menu Keymaps
1952 @cindex menu keymaps
1954 A keymap can operate as a menu as well as defining bindings for
1955 keyboard keys and mouse buttons. Menus are usually actuated with the
1956 mouse, but they can function with the keyboard also. If a menu keymap
1957 is active for the next input event, that activates the keyboard menu
1961 * Defining Menus:: How to make a keymap that defines a menu.
1962 * Mouse Menus:: How users actuate the menu with the mouse.
1963 * Keyboard Menus:: How users actuate the menu with the keyboard.
1964 * Menu Example:: Making a simple menu.
1965 * Menu Bar:: How to customize the menu bar.
1966 * Tool Bar:: A tool bar is a row of images.
1967 * Modifying Menus:: How to add new items to a menu.
1970 @node Defining Menus
1971 @subsection Defining Menus
1972 @cindex defining menus
1973 @cindex menu prompt string
1974 @cindex prompt string (of menu)
1977 A keymap acts as a menu if it has an @dfn{overall prompt string},
1978 which is a string that appears as an element of the keymap.
1979 (@xref{Format of Keymaps}.) The string should describe the purpose of
1980 the menu's commands. Emacs displays the overall prompt string as the
1981 menu title in some cases, depending on the toolkit (if any) used for
1982 displaying menus.@footnote{It is required for menus which do not use a
1983 toolkit, e.g.@: under MS-DOS.} Keyboard menus also display the
1984 overall prompt string.
1986 The easiest way to construct a keymap with a prompt string is to
1987 specify the string as an argument when you call @code{make-keymap},
1988 @code{make-sparse-keymap} (@pxref{Creating Keymaps}), or
1989 @code{define-prefix-command} (@pxref{Definition of
1990 define-prefix-command}). If you do not want the keymap to operate as
1991 a menu, don't specify a prompt string for it.
1993 @defun keymap-prompt keymap
1994 This function returns the overall prompt string of @var{keymap},
1995 or @code{nil} if it has none.
1998 The menu's items are the bindings in the keymap. Each binding
1999 associates an event type to a definition, but the event types have no
2000 significance for the menu appearance. (Usually we use pseudo-events,
2001 symbols that the keyboard cannot generate, as the event types for menu
2002 item bindings.) The menu is generated entirely from the bindings that
2003 correspond in the keymap to these events.
2005 The order of items in the menu is the same as the order of bindings in
2006 the keymap. Since @code{define-key} puts new bindings at the front, you
2007 should define the menu items starting at the bottom of the menu and
2008 moving to the top, if you care about the order. When you add an item to
2009 an existing menu, you can specify its position in the menu using
2010 @code{define-key-after} (@pxref{Modifying Menus}).
2013 * Simple Menu Items:: A simple kind of menu key binding,
2014 limited in capabilities.
2015 * Extended Menu Items:: More powerful menu item definitions
2016 let you specify keywords to enable
2018 * Menu Separators:: Drawing a horizontal line through a menu.
2019 * Alias Menu Items:: Using command aliases in menu items.
2022 @node Simple Menu Items
2023 @subsubsection Simple Menu Items
2025 The simpler (and original) way to define a menu item is to bind some
2026 event type (it doesn't matter what event type) to a binding like this:
2029 (@var{item-string} . @var{real-binding})
2033 The @sc{car}, @var{item-string}, is the string to be displayed in the
2034 menu. It should be short---preferably one to three words. It should
2035 describe the action of the command it corresponds to. Note that it is
2036 not generally possible to display non-@acronym{ASCII} text in menus. It will
2037 work for keyboard menus and will work to a large extent when Emacs is
2038 built with the Gtk+ toolkit.@footnote{In this case, the text is first
2039 encoded using the @code{utf-8} coding system and then rendered by the
2040 toolkit as it sees fit.}
2042 You can also supply a second string, called the help string, as follows:
2045 (@var{item-string} @var{help} . @var{real-binding})
2049 @var{help} specifies a ``help-echo'' string to display while the mouse
2050 is on that item in the same way as @code{help-echo} text properties
2051 (@pxref{Help display}).
2053 As far as @code{define-key} is concerned, @var{item-string} and
2054 @var{help-string} are part of the event's binding. However,
2055 @code{lookup-key} returns just @var{real-binding}, and only
2056 @var{real-binding} is used for executing the key.
2058 If @var{real-binding} is @code{nil}, then @var{item-string} appears in
2059 the menu but cannot be selected.
2061 If @var{real-binding} is a symbol and has a non-@code{nil}
2062 @code{menu-enable} property, that property is an expression that
2063 controls whether the menu item is enabled. Every time the keymap is
2064 used to display a menu, Emacs evaluates the expression, and it enables
2065 the menu item only if the expression's value is non-@code{nil}. When a
2066 menu item is disabled, it is displayed in a ``fuzzy'' fashion, and
2069 The menu bar does not recalculate which items are enabled every time you
2070 look at a menu. This is because the X toolkit requires the whole tree
2071 of menus in advance. To force recalculation of the menu bar, call
2072 @code{force-mode-line-update} (@pxref{Mode Line Format}).
2074 @node Extended Menu Items
2075 @subsubsection Extended Menu Items
2077 @cindex extended menu item
2079 An extended-format menu item is a more flexible and also cleaner
2080 alternative to the simple format. You define an event type with a
2081 binding that's a list starting with the symbol @code{menu-item}.
2082 For a non-selectable string, the binding looks like this:
2085 (menu-item @var{item-name})
2089 A string starting with two or more dashes specifies a separator line;
2090 see @ref{Menu Separators}.
2092 To define a real menu item which can be selected, the extended format
2093 binding looks like this:
2096 (menu-item @var{item-name} @var{real-binding}
2097 . @var{item-property-list})
2101 Here, @var{item-name} is an expression which evaluates to the menu item
2102 string. Thus, the string need not be a constant. The third element,
2103 @var{real-binding}, is the command to execute. The tail of the list,
2104 @var{item-property-list}, has the form of a property list which contains
2107 Here is a table of the properties that are supported:
2110 @item :enable @var{form}
2111 The result of evaluating @var{form} determines whether the item is
2112 enabled (non-@code{nil} means yes). If the item is not enabled,
2113 you can't really click on it.
2115 @item :visible @var{form}
2116 The result of evaluating @var{form} determines whether the item should
2117 actually appear in the menu (non-@code{nil} means yes). If the item
2118 does not appear, then the menu is displayed as if this item were
2121 @item :help @var{help}
2122 The value of this property, @var{help}, specifies a ``help-echo'' string
2123 to display while the mouse is on that item. This is displayed in the
2124 same way as @code{help-echo} text properties (@pxref{Help display}).
2125 Note that this must be a constant string, unlike the @code{help-echo}
2126 property for text and overlays.
2128 @item :button (@var{type} . @var{selected})
2129 This property provides a way to define radio buttons and toggle buttons.
2130 The @sc{car}, @var{type}, says which: it should be @code{:toggle} or
2131 @code{:radio}. The @sc{cdr}, @var{selected}, should be a form; the
2132 result of evaluating it says whether this button is currently selected.
2134 A @dfn{toggle} is a menu item which is labeled as either ``on'' or ``off''
2135 according to the value of @var{selected}. The command itself should
2136 toggle @var{selected}, setting it to @code{t} if it is @code{nil},
2137 and to @code{nil} if it is @code{t}. Here is how the menu item
2138 to toggle the @code{debug-on-error} flag is defined:
2141 (menu-item "Debug on Error" toggle-debug-on-error
2143 . (and (boundp 'debug-on-error)
2148 This works because @code{toggle-debug-on-error} is defined as a command
2149 which toggles the variable @code{debug-on-error}.
2151 @dfn{Radio buttons} are a group of menu items, in which at any time one
2152 and only one is ``selected.'' There should be a variable whose value
2153 says which one is selected at any time. The @var{selected} form for
2154 each radio button in the group should check whether the variable has the
2155 right value for selecting that button. Clicking on the button should
2156 set the variable so that the button you clicked on becomes selected.
2158 @item :key-sequence @var{key-sequence}
2159 This property specifies which key sequence is likely to be bound to the
2160 same command invoked by this menu item. If you specify the right key
2161 sequence, that makes preparing the menu for display run much faster.
2163 If you specify the wrong key sequence, it has no effect; before Emacs
2164 displays @var{key-sequence} in the menu, it verifies that
2165 @var{key-sequence} is really equivalent to this menu item.
2167 @item :key-sequence nil
2168 This property indicates that there is normally no key binding which is
2169 equivalent to this menu item. Using this property saves time in
2170 preparing the menu for display, because Emacs does not need to search
2171 the keymaps for a keyboard equivalent for this menu item.
2173 However, if the user has rebound this item's definition to a key
2174 sequence, Emacs ignores the @code{:keys} property and finds the keyboard
2177 @item :keys @var{string}
2178 This property specifies that @var{string} is the string to display
2179 as the keyboard equivalent for this menu item. You can use
2180 the @samp{\\[...]} documentation construct in @var{string}.
2182 @item :filter @var{filter-fn}
2183 This property provides a way to compute the menu item dynamically.
2184 The property value @var{filter-fn} should be a function of one argument;
2185 when it is called, its argument will be @var{real-binding}. The
2186 function should return the binding to use instead.
2188 Emacs can call this function at any time that it does redisplay or
2189 operates on menu data structures, so you should write it so it can
2190 safely be called at any time.
2193 @node Menu Separators
2194 @subsubsection Menu Separators
2195 @cindex menu separators
2197 A menu separator is a kind of menu item that doesn't display any
2198 text---instead, it divides the menu into subparts with a horizontal line.
2199 A separator looks like this in the menu keymap:
2202 (menu-item @var{separator-type})
2206 where @var{separator-type} is a string starting with two or more dashes.
2208 In the simplest case, @var{separator-type} consists of only dashes.
2209 That specifies the default kind of separator. (For compatibility,
2210 @code{""} and @code{-} also count as separators.)
2212 Certain other values of @var{separator-type} specify a different
2213 style of separator. Here is a table of them:
2218 An extra vertical space, with no actual line.
2220 @item "--single-line"
2221 A single line in the menu's foreground color.
2223 @item "--double-line"
2224 A double line in the menu's foreground color.
2226 @item "--single-dashed-line"
2227 A single dashed line in the menu's foreground color.
2229 @item "--double-dashed-line"
2230 A double dashed line in the menu's foreground color.
2232 @item "--shadow-etched-in"
2233 A single line with a 3D sunken appearance. This is the default,
2234 used separators consisting of dashes only.
2236 @item "--shadow-etched-out"
2237 A single line with a 3D raised appearance.
2239 @item "--shadow-etched-in-dash"
2240 A single dashed line with a 3D sunken appearance.
2242 @item "--shadow-etched-out-dash"
2243 A single dashed line with a 3D raised appearance.
2245 @item "--shadow-double-etched-in"
2246 Two lines with a 3D sunken appearance.
2248 @item "--shadow-double-etched-out"
2249 Two lines with a 3D raised appearance.
2251 @item "--shadow-double-etched-in-dash"
2252 Two dashed lines with a 3D sunken appearance.
2254 @item "--shadow-double-etched-out-dash"
2255 Two dashed lines with a 3D raised appearance.
2258 You can also give these names in another style, adding a colon after
2259 the double-dash and replacing each single dash with capitalization of
2260 the following word. Thus, @code{"--:singleLine"}, is equivalent to
2261 @code{"--single-line"}.
2263 Some systems and display toolkits don't really handle all of these
2264 separator types. If you use a type that isn't supported, the menu
2265 displays a similar kind of separator that is supported.
2267 @node Alias Menu Items
2268 @subsubsection Alias Menu Items
2270 Sometimes it is useful to make menu items that use the ``same''
2271 command but with different enable conditions. The best way to do this
2272 in Emacs now is with extended menu items; before that feature existed,
2273 it could be done by defining alias commands and using them in menu
2274 items. Here's an example that makes two aliases for
2275 @code{toggle-read-only} and gives them different enable conditions:
2278 (defalias 'make-read-only 'toggle-read-only)
2279 (put 'make-read-only 'menu-enable '(not buffer-read-only))
2280 (defalias 'make-writable 'toggle-read-only)
2281 (put 'make-writable 'menu-enable 'buffer-read-only)
2284 When using aliases in menus, often it is useful to display the
2285 equivalent key bindings for the ``real'' command name, not the aliases
2286 (which typically don't have any key bindings except for the menu
2287 itself). To request this, give the alias symbol a non-@code{nil}
2288 @code{menu-alias} property. Thus,
2291 (put 'make-read-only 'menu-alias t)
2292 (put 'make-writable 'menu-alias t)
2296 causes menu items for @code{make-read-only} and @code{make-writable} to
2297 show the keyboard bindings for @code{toggle-read-only}.
2300 @subsection Menus and the Mouse
2302 The usual way to make a menu keymap produce a menu is to make it the
2303 definition of a prefix key. (A Lisp program can explicitly pop up a
2304 menu and receive the user's choice---see @ref{Pop-Up Menus}.)
2306 If the prefix key ends with a mouse event, Emacs handles the menu keymap
2307 by popping up a visible menu, so that the user can select a choice with
2308 the mouse. When the user clicks on a menu item, the event generated is
2309 whatever character or symbol has the binding that brought about that
2310 menu item. (A menu item may generate a series of events if the menu has
2311 multiple levels or comes from the menu bar.)
2313 It's often best to use a button-down event to trigger the menu. Then
2314 the user can select a menu item by releasing the button.
2316 A single keymap can appear as multiple menu panes, if you explicitly
2317 arrange for this. The way to do this is to make a keymap for each pane,
2318 then create a binding for each of those maps in the main keymap of the
2319 menu. Give each of these bindings an item string that starts with
2320 @samp{@@}. The rest of the item string becomes the name of the pane.
2321 See the file @file{lisp/mouse.el} for an example of this. Any ordinary
2322 bindings with @samp{@@}-less item strings are grouped into one pane,
2323 which appears along with the other panes explicitly created for the
2326 X toolkit menus don't have panes; instead, they can have submenus.
2327 Every nested keymap becomes a submenu, whether the item string starts
2328 with @samp{@@} or not. In a toolkit version of Emacs, the only thing
2329 special about @samp{@@} at the beginning of an item string is that the
2330 @samp{@@} doesn't appear in the menu item.
2332 Multiple keymaps that define the same menu prefix key produce
2333 separate panes or separate submenus.
2335 @node Keyboard Menus
2336 @subsection Menus and the Keyboard
2338 When a prefix key ending with a keyboard event (a character or
2339 function key) has a definition that is a menu keymap, the keymap
2340 operates as a keyboard menu; the user specifies the next event by
2341 choosing a menu item with the keyboard.
2343 Emacs displays the keyboard menu with the map's overall prompt
2344 string, followed by the alternatives (the item strings of the map's
2345 bindings), in the echo area. If the bindings don't all fit at once,
2346 the user can type @key{SPC} to see the next line of alternatives.
2347 Successive uses of @key{SPC} eventually get to the end of the menu and
2348 then cycle around to the beginning. (The variable
2349 @code{menu-prompt-more-char} specifies which character is used for
2350 this; @key{SPC} is the default.)
2352 When the user has found the desired alternative from the menu, he or
2353 she should type the corresponding character---the one whose binding is
2357 In a menu intended for keyboard use, each menu item must clearly
2358 indicate what character to type. The best convention to use is to make
2359 the character the first letter of the item string---that is something
2360 users will understand without being told. We plan to change this; by
2361 the time you read this manual, keyboard menus may explicitly name the
2362 key for each alternative.
2365 This way of using menus in an Emacs-like editor was inspired by the
2368 @defvar menu-prompt-more-char
2369 This variable specifies the character to use to ask to see
2370 the next line of a menu. Its initial value is 32, the code
2375 @subsection Menu Example
2376 @cindex menu definition example
2378 Here is a complete example of defining a menu keymap. It is the
2379 definition of the @samp{Replace} submenu in the @samp{Edit} menu in
2380 the menu bar, and it uses the extended menu item format
2381 (@pxref{Extended Menu Items}). First we create the keymap, and give
2385 (defvar menu-bar-replace-menu (make-sparse-keymap "Replace"))
2389 Next we define the menu items:
2392 (define-key menu-bar-replace-menu [tags-repl-continue]
2393 '(menu-item "Continue Replace" tags-loop-continue
2394 :help "Continue last tags replace operation"))
2395 (define-key menu-bar-replace-menu [tags-repl]
2396 '(menu-item "Replace in tagged files" tags-query-replace
2397 :help "Interactively replace a regexp in all tagged files"))
2398 (define-key menu-bar-replace-menu [separator-replace-tags]
2404 Note the symbols which the bindings are ``made for''; these appear
2405 inside square brackets, in the key sequence being defined. In some
2406 cases, this symbol is the same as the command name; sometimes it is
2407 different. These symbols are treated as ``function keys,'' but they are
2408 not real function keys on the keyboard. They do not affect the
2409 functioning of the menu itself, but they are ``echoed'' in the echo area
2410 when the user selects from the menu, and they appear in the output of
2411 @code{where-is} and @code{apropos}.
2413 The menu in this example is intended for use with the mouse. If a
2414 menu is intended for use with the keyboard, that is, if it is bound to
2415 a key sequence ending with a keyboard event, then the menu items
2416 should be bound to characters or ``real'' function keys, that can be
2417 typed with the keyboard.
2419 The binding whose definition is @code{("--")} is a separator line.
2420 Like a real menu item, the separator has a key symbol, in this case
2421 @code{separator-replace-tags}. If one menu has two separators, they
2422 must have two different key symbols.
2424 Here is how we make this menu appear as an item in the parent menu:
2427 (define-key menu-bar-edit-menu [replace]
2428 (list 'menu-item "Replace" menu-bar-replace-menu))
2432 Note that this incorporates the submenu keymap, which is the value of
2433 the variable @code{menu-bar-replace-menu}, rather than the symbol
2434 @code{menu-bar-replace-menu} itself. Using that symbol in the parent
2435 menu item would be meaningless because @code{menu-bar-replace-menu} is
2438 If you wanted to attach the same replace menu to a mouse click, you
2442 (define-key global-map [C-S-down-mouse-1]
2443 menu-bar-replace-menu)
2447 @subsection The Menu Bar
2450 Most window systems allow each frame to have a @dfn{menu bar}---a
2451 permanently displayed menu stretching horizontally across the top of
2452 the frame. (In order for a frame to display a menu bar, its
2453 @code{menu-bar-lines} parameter must be greater than zero.
2454 @xref{Layout Parameters}.)
2456 The items of the menu bar are the subcommands of the fake ``function
2457 key'' @code{menu-bar}, as defined in the active keymaps.
2459 To add an item to the menu bar, invent a fake ``function key'' of your
2460 own (let's call it @var{key}), and make a binding for the key sequence
2461 @code{[menu-bar @var{key}]}. Most often, the binding is a menu keymap,
2462 so that pressing a button on the menu bar item leads to another menu.
2464 When more than one active keymap defines the same fake function key
2465 for the menu bar, the item appears just once. If the user clicks on
2466 that menu bar item, it brings up a single, combined menu containing
2467 all the subcommands of that item---the global subcommands, the local
2468 subcommands, and the minor mode subcommands.
2470 The variable @code{overriding-local-map} is normally ignored when
2471 determining the menu bar contents. That is, the menu bar is computed
2472 from the keymaps that would be active if @code{overriding-local-map}
2473 were @code{nil}. @xref{Active Keymaps}.
2475 Here's an example of setting up a menu bar item:
2479 (modify-frame-parameters (selected-frame)
2480 '((menu-bar-lines . 2)))
2484 ;; @r{Make a menu keymap (with a prompt string)}
2485 ;; @r{and make it the menu bar item's definition.}
2486 (define-key global-map [menu-bar words]
2487 (cons "Words" (make-sparse-keymap "Words")))
2491 ;; @r{Define specific subcommands in this menu.}
2492 (define-key global-map
2493 [menu-bar words forward]
2494 '("Forward word" . forward-word))
2497 (define-key global-map
2498 [menu-bar words backward]
2499 '("Backward word" . backward-word))
2503 A local keymap can cancel a menu bar item made by the global keymap by
2504 rebinding the same fake function key with @code{undefined} as the
2505 binding. For example, this is how Dired suppresses the @samp{Edit} menu
2509 (define-key dired-mode-map [menu-bar edit] 'undefined)
2513 Here, @code{edit} is the fake function key used by the global map for
2514 the @samp{Edit} menu bar item. The main reason to suppress a global
2515 menu bar item is to regain space for mode-specific items.
2517 @defvar menu-bar-final-items
2518 Normally the menu bar shows global items followed by items defined by the
2521 This variable holds a list of fake function keys for items to display at
2522 the end of the menu bar rather than in normal sequence. The default
2523 value is @code{(help-menu)}; thus, the @samp{Help} menu item normally appears
2524 at the end of the menu bar, following local menu items.
2527 @defvar menu-bar-update-hook
2528 This normal hook is run by redisplay to update the menu bar contents,
2529 before redisplaying the menu bar. You can use it to update submenus
2530 whose contents should vary. Since this hook is run frequently, we
2531 advise you to ensure that the functions it calls do not take much time
2535 Next to every menu bar item, Emacs displays a key binding that runs
2536 the same command (if such a key binding exists). This serves as a
2537 convenient hint for users who do not know the key binding. If a
2538 command has multiple bindings, Emacs normally displays the first one
2539 it finds. You can specify one particular key binding by assigning an
2540 @code{:advertised-binding} symbol property to the command. For
2541 instance, the following tells Emacs to show @kbd{C-/} for the
2542 @code{undo} menu item:
2545 (put 'undo :advertised-binding [?\C-/])
2549 If the @code{:advertised-binding} property specifies a key binding
2550 that the command does not actually have, it is ignored.
2553 @subsection Tool bars
2556 A @dfn{tool bar} is a row of icons at the top of a frame, that execute
2557 commands when you click on them---in effect, a kind of graphical menu
2560 The frame parameter @code{tool-bar-lines} (X resource @samp{toolBar})
2561 controls how many lines' worth of height to reserve for the tool bar. A
2562 zero value suppresses the tool bar. If the value is nonzero, and
2563 @code{auto-resize-tool-bars} is non-@code{nil}, the tool bar expands and
2564 contracts automatically as needed to hold the specified contents.
2566 If the value of @code{auto-resize-tool-bars} is @code{grow-only},
2567 the tool bar expands automatically, but does not contract automatically.
2568 To contract the tool bar, the user has to redraw the frame by entering
2571 The tool bar contents are controlled by a menu keymap attached to a
2572 fake ``function key'' called @code{tool-bar} (much like the way the menu
2573 bar is controlled). So you define a tool bar item using
2574 @code{define-key}, like this:
2577 (define-key global-map [tool-bar @var{key}] @var{item})
2581 where @var{key} is a fake ``function key'' to distinguish this item from
2582 other items, and @var{item} is a menu item key binding (@pxref{Extended
2583 Menu Items}), which says how to display this item and how it behaves.
2585 The usual menu keymap item properties, @code{:visible},
2586 @code{:enable}, @code{:button}, and @code{:filter}, are useful in
2587 tool bar bindings and have their normal meanings. The @var{real-binding}
2588 in the item must be a command, not a keymap; in other words, it does not
2589 work to define a tool bar icon as a prefix key.
2591 The @code{:help} property specifies a ``help-echo'' string to display
2592 while the mouse is on that item. This is displayed in the same way as
2593 @code{help-echo} text properties (@pxref{Help display}).
2595 In addition, you should use the @code{:image} property;
2596 this is how you specify the image to display in the tool bar:
2599 @item :image @var{image}
2600 @var{images} is either a single image specification or a vector of four
2601 image specifications. If you use a vector of four,
2602 one of them is used, depending on circumstances:
2606 Used when the item is enabled and selected.
2608 Used when the item is enabled and deselected.
2610 Used when the item is disabled and selected.
2612 Used when the item is disabled and deselected.
2616 If @var{image} is a single image specification, Emacs draws the tool bar
2617 button in disabled state by applying an edge-detection algorithm to the
2620 The @code{:rtl} property specifies an alternative image to use for
2621 right-to-left languages. Only the Gtk+ version of Emacs supports this
2624 The default tool bar is defined so that items specific to editing do not
2625 appear for major modes whose command symbol has a @code{mode-class}
2626 property of @code{special} (@pxref{Major Mode Conventions}). Major
2627 modes may add items to the global bar by binding @code{[tool-bar
2628 @var{foo}]} in their local map. It makes sense for some major modes to
2629 replace the default tool bar items completely, since not many can be
2630 accommodated conveniently, and the default bindings make this easy by
2631 using an indirection through @code{tool-bar-map}.
2633 @defvar tool-bar-map
2634 By default, the global map binds @code{[tool-bar]} as follows:
2636 (global-set-key [tool-bar]
2637 '(menu-item "tool bar" ignore
2638 :filter (lambda (ignore) tool-bar-map)))
2641 Thus the tool bar map is derived dynamically from the value of variable
2642 @code{tool-bar-map} and you should normally adjust the default (global)
2643 tool bar by changing that map. Major modes may replace the global bar
2644 completely by making @code{tool-bar-map} buffer-local and set to a
2645 keymap containing only the desired items. Info mode provides an
2649 There are two convenience functions for defining tool bar items, as
2652 @defun tool-bar-add-item icon def key &rest props
2653 This function adds an item to the tool bar by modifying
2654 @code{tool-bar-map}. The image to use is defined by @var{icon}, which
2655 is the base name of an XPM, XBM or PBM image file to be located by
2656 @code{find-image}. Given a value @samp{"exit"}, say, @file{exit.xpm},
2657 @file{exit.pbm} and @file{exit.xbm} would be searched for in that order
2658 on a color display. On a monochrome display, the search order is
2659 @samp{.pbm}, @samp{.xbm} and @samp{.xpm}. The binding to use is the
2660 command @var{def}, and @var{key} is the fake function key symbol in the
2661 prefix keymap. The remaining arguments @var{props} are additional
2662 property list elements to add to the menu item specification.
2664 To define items in some local map, bind @code{tool-bar-map} with
2665 @code{let} around calls of this function:
2667 (defvar foo-tool-bar-map
2668 (let ((tool-bar-map (make-sparse-keymap)))
2669 (tool-bar-add-item @dots{})
2675 @defun tool-bar-add-item-from-menu command icon &optional map &rest props
2676 This function is a convenience for defining tool bar items which are
2677 consistent with existing menu bar bindings. The binding of
2678 @var{command} is looked up in the menu bar in @var{map} (default
2679 @code{global-map}) and modified to add an image specification for
2680 @var{icon}, which is found in the same way as by
2681 @code{tool-bar-add-item}. The resulting binding is then placed in
2682 @code{tool-bar-map}, so use this function only for global tool bar
2685 @var{map} must contain an appropriate keymap bound to
2686 @code{[menu-bar]}. The remaining arguments @var{props} are additional
2687 property list elements to add to the menu item specification.
2690 @defun tool-bar-local-item-from-menu command icon in-map &optional from-map &rest props
2691 This function is used for making non-global tool bar items. Use it
2692 like @code{tool-bar-add-item-from-menu} except that @var{in-map}
2693 specifies the local map to make the definition in. The argument
2694 @var{from-map} is like the @var{map} argument of
2695 @code{tool-bar-add-item-from-menu}.
2698 @defvar auto-resize-tool-bars
2699 If this variable is non-@code{nil}, the tool bar automatically resizes to
2700 show all defined tool bar items---but not larger than a quarter of the
2703 If the value is @code{grow-only}, the tool bar expands automatically,
2704 but does not contract automatically. To contract the tool bar, the
2705 user has to redraw the frame by entering @kbd{C-l}.
2707 If Emacs is built with GTK or Nextstep, the tool bar can only show one
2708 line, so this variable has no effect.
2711 @defvar auto-raise-tool-bar-buttons
2712 If this variable is non-@code{nil}, tool bar items display
2713 in raised form when the mouse moves over them.
2716 @defvar tool-bar-button-margin
2717 This variable specifies an extra margin to add around tool bar items.
2718 The value is an integer, a number of pixels. The default is 4.
2721 @defvar tool-bar-button-relief
2722 This variable specifies the shadow width for tool bar items.
2723 The value is an integer, a number of pixels. The default is 1.
2726 @defvar tool-bar-border
2727 This variable specifies the height of the border drawn below the tool
2728 bar area. An integer value specifies height as a number of pixels.
2729 If the value is one of @code{internal-border-width} (the default) or
2730 @code{border-width}, the tool bar border height corresponds to the
2731 corresponding frame parameter.
2734 You can define a special meaning for clicking on a tool bar item with
2735 the shift, control, meta, etc., modifiers. You do this by setting up
2736 additional items that relate to the original item through the fake
2737 function keys. Specifically, the additional items should use the
2738 modified versions of the same fake function key used to name the
2741 Thus, if the original item was defined this way,
2744 (define-key global-map [tool-bar shell]
2745 '(menu-item "Shell" shell
2746 :image (image :type xpm :file "shell.xpm")))
2750 then here is how you can define clicking on the same tool bar image with
2754 (define-key global-map [tool-bar S-shell] 'some-command)
2757 @xref{Function Keys}, for more information about how to add modifiers to
2760 @node Modifying Menus
2761 @subsection Modifying Menus
2763 When you insert a new item in an existing menu, you probably want to
2764 put it in a particular place among the menu's existing items. If you
2765 use @code{define-key} to add the item, it normally goes at the front of
2766 the menu. To put it elsewhere in the menu, use @code{define-key-after}:
2768 @defun define-key-after map key binding &optional after
2769 Define a binding in @var{map} for @var{key}, with value @var{binding},
2770 just like @code{define-key}, but position the binding in @var{map} after
2771 the binding for the event @var{after}. The argument @var{key} should be
2772 of length one---a vector or string with just one element. But
2773 @var{after} should be a single event type---a symbol or a character, not
2774 a sequence. The new binding goes after the binding for @var{after}. If
2775 @var{after} is @code{t} or is omitted, then the new binding goes last, at
2776 the end of the keymap. However, new bindings are added before any
2782 (define-key-after my-menu [drink]
2783 '("Drink" . drink-command) 'eat)
2787 makes a binding for the fake function key @key{DRINK} and puts it
2788 right after the binding for @key{EAT}.
2790 Here is how to insert an item called @samp{Work} in the @samp{Signals}
2791 menu of Shell mode, after the item @code{break}:
2795 (lookup-key shell-mode-map [menu-bar signals])
2796 [work] '("Work" . work-command) 'break)