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1 | @c -*-texinfo-*- |
2 | @c This is part of the GNU Emacs Lisp Reference Manual. | |
53a1239b | 3 | @c Copyright (C) 1990-1994, 1998-2012 Free Software Foundation, Inc. |
b8d4c8d0 | 4 | @c See the file elisp.texi for copying conditions. |
ecc6530d | 5 | @node Keymaps |
b8d4c8d0 GM |
6 | @chapter Keymaps |
7 | @cindex keymap | |
8 | ||
9 | The command bindings of input events are recorded in data structures | |
10 | called @dfn{keymaps}. Each entry in a keymap associates (or | |
11 | @dfn{binds}) an individual event type, either to another keymap or to | |
12 | a command. When an event type is bound to a keymap, that keymap is | |
13 | used to look up the next input event; this continues until a command | |
14 | is found. The whole process is called @dfn{key lookup}. | |
15 | ||
16 | @menu | |
d24880de | 17 | * Key Sequences:: Key sequences as Lisp objects. |
b8d4c8d0 | 18 | * Keymap Basics:: Basic concepts of keymaps. |
d24880de GM |
19 | * Format of Keymaps:: What a keymap looks like as a Lisp object. |
20 | * Creating Keymaps:: Functions to create and copy keymaps. | |
21 | * Inheritance and Keymaps:: How one keymap can inherit the bindings | |
22 | of another keymap. | |
b8d4c8d0 GM |
23 | * Prefix Keys:: Defining a key with a keymap as its definition. |
24 | * Active Keymaps:: How Emacs searches the active keymaps | |
25 | for a key binding. | |
26 | * Searching Keymaps:: A pseudo-Lisp summary of searching active maps. | |
27 | * Controlling Active Maps:: Each buffer has a local keymap | |
28 | to override the standard (global) bindings. | |
d24880de | 29 | A minor mode can also override them. |
b8d4c8d0 GM |
30 | * Key Lookup:: Finding a key's binding in one keymap. |
31 | * Functions for Key Lookup:: How to request key lookup. | |
32 | * Changing Key Bindings:: Redefining a key in a keymap. | |
33 | * Remapping Commands:: A keymap can translate one command to another. | |
34 | * Translation Keymaps:: Keymaps for translating sequences of events. | |
35 | * Key Binding Commands:: Interactive interfaces for redefining keys. | |
36 | * Scanning Keymaps:: Looking through all keymaps, for printing help. | |
d24880de | 37 | * Menu Keymaps:: Defining a menu as a keymap. |
b8d4c8d0 GM |
38 | @end menu |
39 | ||
40 | @node Key Sequences | |
41 | @section Key Sequences | |
42 | @cindex key | |
43 | @cindex keystroke | |
44 | @cindex key sequence | |
45 | ||
46 | A @dfn{key sequence}, or @dfn{key} for short, is a sequence of one | |
47 | or more input events that form a unit. Input events include | |
1ada2e55 EZ |
48 | characters, function keys, mouse actions, or system events external to |
49 | Emacs, such as @code{iconify-frame} (@pxref{Input Events}). | |
b8d4c8d0 GM |
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. | |
53 | ||
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 | |
64 | @kbd{C-x l}. | |
65 | ||
1ada2e55 EZ |
66 | Key sequences containing function keys, mouse button events, system |
67 | events, or non-@acronym{ASCII} characters such as @kbd{C-=} or | |
68 | @kbd{H-a} cannot be represented as strings; they have to be | |
69 | represented as vectors. | |
b8d4c8d0 GM |
70 | |
71 | In the vector representation, each element of the vector represents | |
72 | an input event, in its Lisp form. @xref{Input Events}. For example, | |
73 | the vector @code{[?\C-x ?l]} represents the key sequence @kbd{C-x l}. | |
74 | ||
75 | For examples of key sequences written in string and vector | |
76 | representations, @ref{Init Rebinding,,, emacs, The GNU Emacs Manual}. | |
77 | ||
78 | @defmac kbd keyseq-text | |
79 | This macro converts the text @var{keyseq-text} (a string constant) | |
80 | into a key sequence (a string or vector constant). The contents of | |
81 | @var{keyseq-text} should describe the key sequence using almost the same | |
82 | syntax used in this manual. More precisely, it uses the same syntax | |
83 | that Edit Macro mode uses for editing keyboard macros (@pxref{Edit | |
84 | Keyboard Macro,,, emacs, The GNU Emacs Manual}); you must surround | |
85 | function key names with @samp{<@dots{}>}. | |
86 | ||
87 | @example | |
88 | (kbd "C-x") @result{} "\C-x" | |
89 | (kbd "C-x C-f") @result{} "\C-x\C-f" | |
90 | (kbd "C-x 4 C-f") @result{} "\C-x4\C-f" | |
91 | (kbd "X") @result{} "X" | |
92 | (kbd "RET") @result{} "\^M" | |
93 | (kbd "C-c SPC") @result{} "\C-c@ " | |
94 | (kbd "<f1> SPC") @result{} [f1 32] | |
95 | (kbd "C-M-<down>") @result{} [C-M-down] | |
96 | @end example | |
97 | ||
98 | This macro is not meant for use with arguments that vary---only | |
99 | with string constants. | |
100 | @end defmac | |
101 | ||
102 | @node Keymap Basics | |
103 | @section Keymap Basics | |
104 | @cindex key binding | |
105 | @cindex binding of a key | |
106 | @cindex complete key | |
107 | @cindex undefined key | |
108 | ||
109 | A keymap is a Lisp data structure that specifies @dfn{key bindings} | |
110 | for various key sequences. | |
111 | ||
112 | A single keymap directly specifies definitions for individual | |
113 | events. When a key sequence consists of a single event, its binding | |
114 | in a keymap is the keymap's definition for that event. The binding of | |
115 | a longer key sequence is found by an iterative process: first find the | |
116 | definition of the first event (which must itself be a keymap); then | |
117 | find the second event's definition in that keymap, and so on until all | |
118 | the events in the key sequence have been processed. | |
119 | ||
120 | If the binding of a key sequence is a keymap, we call the key sequence | |
121 | a @dfn{prefix key}. Otherwise, we call it a @dfn{complete key} (because | |
122 | no more events can be added to it). If the binding is @code{nil}, | |
123 | we call the key @dfn{undefined}. Examples of prefix keys are @kbd{C-c}, | |
124 | @kbd{C-x}, and @kbd{C-x 4}. Examples of defined complete keys are | |
125 | @kbd{X}, @key{RET}, and @kbd{C-x 4 C-f}. Examples of undefined complete | |
126 | keys are @kbd{C-x C-g}, and @kbd{C-c 3}. @xref{Prefix Keys}, for more | |
127 | details. | |
128 | ||
129 | The rule for finding the binding of a key sequence assumes that the | |
130 | intermediate bindings (found for the events before the last) are all | |
131 | keymaps; if this is not so, the sequence of events does not form a | |
132 | unit---it is not really one key sequence. In other words, removing one | |
133 | or more events from the end of any valid key sequence must always yield | |
134 | a prefix key. For example, @kbd{C-f C-n} is not a key sequence; | |
135 | @kbd{C-f} is not a prefix key, so a longer sequence starting with | |
136 | @kbd{C-f} cannot be a key sequence. | |
137 | ||
138 | The set of possible multi-event key sequences depends on the bindings | |
139 | for prefix keys; therefore, it can be different for different keymaps, | |
140 | and can change when bindings are changed. However, a one-event sequence | |
141 | is always a key sequence, because it does not depend on any prefix keys | |
142 | for its well-formedness. | |
143 | ||
144 | At any time, several primary keymaps are @dfn{active}---that is, in | |
145 | use for finding key bindings. These are the @dfn{global map}, which is | |
146 | shared by all buffers; the @dfn{local keymap}, which is usually | |
147 | associated with a specific major mode; and zero or more @dfn{minor mode | |
148 | keymaps}, which belong to currently enabled minor modes. (Not all minor | |
149 | modes have keymaps.) The local keymap bindings shadow (i.e., take | |
150 | precedence over) the corresponding global bindings. The minor mode | |
151 | keymaps shadow both local and global keymaps. @xref{Active Keymaps}, | |
152 | for details. | |
153 | ||
154 | @node Format of Keymaps | |
155 | @section Format of Keymaps | |
156 | @cindex format of keymaps | |
157 | @cindex keymap format | |
158 | @cindex full keymap | |
159 | @cindex sparse keymap | |
160 | ||
161 | Each keymap is a list whose @sc{car} is the symbol @code{keymap}. The | |
162 | remaining elements of the list define the key bindings of the keymap. | |
163 | A symbol whose function definition is a keymap is also a keymap. Use | |
164 | the function @code{keymapp} (see below) to test whether an object is a | |
165 | keymap. | |
166 | ||
167 | Several kinds of elements may appear in a keymap, after the symbol | |
168 | @code{keymap} that begins it: | |
169 | ||
170 | @table @code | |
171 | @item (@var{type} .@: @var{binding}) | |
172 | This specifies one binding, for events of type @var{type}. Each | |
173 | ordinary binding applies to events of a particular @dfn{event type}, | |
174 | which is always a character or a symbol. @xref{Classifying Events}. | |
175 | In this kind of binding, @var{binding} is a command. | |
176 | ||
3d8badf4 | 177 | @item (@var{type} @var{item-name} .@: @var{binding}) |
b8d4c8d0 | 178 | This specifies a binding which is also a simple menu item that |
3d8badf4 | 179 | displays as @var{item-name} in the menu. @xref{Simple Menu Items}. |
b8d4c8d0 | 180 | |
3d8badf4 | 181 | @item (@var{type} @var{item-name} @var{help-string} .@: @var{binding}) |
b8d4c8d0 GM |
182 | This is a simple menu item with help string @var{help-string}. |
183 | ||
184 | @item (@var{type} menu-item .@: @var{details}) | |
185 | This specifies a binding which is also an extended menu item. This | |
186 | allows use of other features. @xref{Extended Menu Items}. | |
187 | ||
188 | @item (t .@: @var{binding}) | |
189 | @cindex default key binding | |
190 | This specifies a @dfn{default key binding}; any event not bound by other | |
191 | elements of the keymap is given @var{binding} as its binding. Default | |
192 | bindings allow a keymap to bind all possible event types without having | |
193 | to enumerate all of them. A keymap that has a default binding | |
194 | completely masks any lower-precedence keymap, except for events | |
195 | explicitly bound to @code{nil} (see below). | |
196 | ||
197 | @item @var{char-table} | |
198 | If an element of a keymap is a char-table, it counts as holding | |
199 | bindings for all character events with no modifier bits | |
200 | (@pxref{modifier bits}): element @var{n} is the binding for the | |
201 | character with code @var{n}. This is a compact way to record lots of | |
202 | bindings. A keymap with such a char-table is called a @dfn{full | |
203 | keymap}. Other keymaps are called @dfn{sparse keymaps}. | |
204 | ||
205 | @item @var{string} | |
206 | @cindex keymap prompt string | |
207 | @cindex overall prompt string | |
208 | @cindex prompt string of keymap | |
209 | Aside from elements that specify bindings for keys, a keymap can also | |
210 | have a string as an element. This is called the @dfn{overall prompt | |
211 | string} and makes it possible to use the keymap as a menu. | |
212 | @xref{Defining Menus}. | |
213 | @end table | |
214 | ||
215 | When the binding is @code{nil}, it doesn't constitute a definition | |
216 | but it does take precedence over a default binding or a binding in the | |
217 | parent keymap. On the other hand, a binding of @code{nil} does | |
218 | @emph{not} override lower-precedence keymaps; thus, if the local map | |
219 | gives a binding of @code{nil}, Emacs uses the binding from the | |
220 | global map. | |
221 | ||
222 | @cindex meta characters lookup | |
223 | Keymaps do not directly record bindings for the meta characters. | |
224 | Instead, meta characters are regarded for purposes of key lookup as | |
225 | sequences of two characters, the first of which is @key{ESC} (or | |
226 | whatever is currently the value of @code{meta-prefix-char}). Thus, the | |
227 | key @kbd{M-a} is internally represented as @kbd{@key{ESC} a}, and its | |
228 | global binding is found at the slot for @kbd{a} in @code{esc-map} | |
229 | (@pxref{Prefix Keys}). | |
230 | ||
231 | This conversion applies only to characters, not to function keys or | |
232 | other input events; thus, @kbd{M-@key{end}} has nothing to do with | |
233 | @kbd{@key{ESC} @key{end}}. | |
234 | ||
235 | Here as an example is the local keymap for Lisp mode, a sparse | |
3d8badf4 CY |
236 | keymap. It defines bindings for @key{DEL}, @kbd{C-c C-z}, |
237 | @kbd{C-M-q}, and @kbd{C-M-x} (the actual value also contains a menu | |
238 | binding, which is omitted here for the sake of brevity). | |
b8d4c8d0 GM |
239 | |
240 | @example | |
241 | @group | |
242 | lisp-mode-map | |
243 | @result{} | |
244 | @end group | |
245 | @group | |
246 | (keymap | |
247 | (3 keymap | |
248 | ;; @kbd{C-c C-z} | |
249 | (26 . run-lisp)) | |
250 | @end group | |
251 | @group | |
252 | (27 keymap | |
3d8badf4 CY |
253 | ;; @r{@kbd{C-M-x}, treated as @kbd{@key{ESC} C-x}} |
254 | (24 . lisp-send-defun)) | |
b8d4c8d0 GM |
255 | @end group |
256 | @group | |
257 | ;; @r{This part is inherited from @code{lisp-mode-shared-map}.} | |
258 | keymap | |
259 | ;; @key{DEL} | |
260 | (127 . backward-delete-char-untabify) | |
261 | @end group | |
262 | @group | |
263 | (27 keymap | |
3d8badf4 CY |
264 | ;; @r{@kbd{C-M-q}, treated as @kbd{@key{ESC} C-q}} |
265 | (17 . indent-sexp))) | |
b8d4c8d0 GM |
266 | @end group |
267 | @end example | |
268 | ||
269 | @defun keymapp object | |
270 | This function returns @code{t} if @var{object} is a keymap, @code{nil} | |
271 | otherwise. More precisely, this function tests for a list whose | |
272 | @sc{car} is @code{keymap}, or for a symbol whose function definition | |
273 | satisfies @code{keymapp}. | |
274 | ||
275 | @example | |
276 | @group | |
277 | (keymapp '(keymap)) | |
278 | @result{} t | |
279 | @end group | |
280 | @group | |
281 | (fset 'foo '(keymap)) | |
282 | (keymapp 'foo) | |
283 | @result{} t | |
284 | @end group | |
285 | @group | |
286 | (keymapp (current-global-map)) | |
287 | @result{} t | |
288 | @end group | |
289 | @end example | |
290 | @end defun | |
291 | ||
292 | @node Creating Keymaps | |
293 | @section Creating Keymaps | |
294 | @cindex creating keymaps | |
295 | ||
296 | Here we describe the functions for creating keymaps. | |
297 | ||
298 | @defun make-sparse-keymap &optional prompt | |
299 | This function creates and returns a new sparse keymap with no entries. | |
300 | (A sparse keymap is the kind of keymap you usually want.) The new | |
301 | keymap does not contain a char-table, unlike @code{make-keymap}, and | |
302 | does not bind any events. | |
303 | ||
304 | @example | |
305 | @group | |
306 | (make-sparse-keymap) | |
307 | @result{} (keymap) | |
308 | @end group | |
309 | @end example | |
310 | ||
311 | If you specify @var{prompt}, that becomes the overall prompt string | |
312 | for the keymap. You should specify this only for menu keymaps | |
313 | (@pxref{Defining Menus}). A keymap with an overall prompt string will | |
314 | always present a mouse menu or a keyboard menu if it is active for | |
315 | looking up the next input event. Don't specify an overall prompt string | |
316 | for the main map of a major or minor mode, because that would cause | |
317 | the command loop to present a keyboard menu every time. | |
318 | @end defun | |
319 | ||
320 | @defun make-keymap &optional prompt | |
321 | This function creates and returns a new full keymap. That keymap | |
322 | contains a char-table (@pxref{Char-Tables}) with slots for all | |
323 | characters without modifiers. The new keymap initially binds all | |
324 | these characters to @code{nil}, and does not bind any other kind of | |
325 | event. The argument @var{prompt} specifies a | |
326 | prompt string, as in @code{make-sparse-keymap}. | |
327 | ||
328 | @example | |
329 | @group | |
330 | (make-keymap) | |
331 | @result{} (keymap #^[t nil nil nil @dots{} nil nil keymap]) | |
332 | @end group | |
333 | @end example | |
334 | ||
335 | A full keymap is more efficient than a sparse keymap when it holds | |
336 | lots of bindings; for just a few, the sparse keymap is better. | |
337 | @end defun | |
338 | ||
339 | @defun copy-keymap keymap | |
340 | This function returns a copy of @var{keymap}. Any keymaps that | |
341 | appear directly as bindings in @var{keymap} are also copied recursively, | |
342 | and so on to any number of levels. However, recursive copying does not | |
343 | take place when the definition of a character is a symbol whose function | |
344 | definition is a keymap; the same symbol appears in the new copy. | |
345 | @c Emacs 19 feature | |
346 | ||
347 | @example | |
348 | @group | |
349 | (setq map (copy-keymap (current-local-map))) | |
350 | @result{} (keymap | |
351 | @end group | |
352 | @group | |
353 | ;; @r{(This implements meta characters.)} | |
354 | (27 keymap | |
355 | (83 . center-paragraph) | |
356 | (115 . center-line)) | |
357 | (9 . tab-to-tab-stop)) | |
358 | @end group | |
359 | ||
360 | @group | |
361 | (eq map (current-local-map)) | |
362 | @result{} nil | |
363 | @end group | |
364 | @group | |
365 | (equal map (current-local-map)) | |
366 | @result{} t | |
367 | @end group | |
368 | @end example | |
369 | @end defun | |
370 | ||
371 | @node Inheritance and Keymaps | |
372 | @section Inheritance and Keymaps | |
373 | @cindex keymap inheritance | |
02676e5d | 374 | @cindex inheritance, keymap |
b8d4c8d0 GM |
375 | |
376 | A keymap can inherit the bindings of another keymap, which we call the | |
377 | @dfn{parent keymap}. Such a keymap looks like this: | |
378 | ||
379 | @example | |
380 | (keymap @var{elements}@dots{} . @var{parent-keymap}) | |
381 | @end example | |
382 | ||
383 | @noindent | |
384 | The effect is that this keymap inherits all the bindings of | |
385 | @var{parent-keymap}, whatever they may be at the time a key is looked up, | |
386 | but can add to them or override them with @var{elements}. | |
387 | ||
388 | If you change the bindings in @var{parent-keymap} using | |
389 | @code{define-key} or other key-binding functions, these changed | |
390 | bindings are visible in the inheriting keymap, unless shadowed by the | |
391 | bindings made by @var{elements}. The converse is not true: if you use | |
392 | @code{define-key} to change bindings in the inheriting keymap, these | |
393 | changes are recorded in @var{elements}, but have no effect on | |
394 | @var{parent-keymap}. | |
395 | ||
396 | The proper way to construct a keymap with a parent is to use | |
397 | @code{set-keymap-parent}; if you have code that directly constructs a | |
398 | keymap with a parent, please convert the program to use | |
399 | @code{set-keymap-parent} instead. | |
400 | ||
401 | @defun keymap-parent keymap | |
402 | This returns the parent keymap of @var{keymap}. If @var{keymap} | |
403 | has no parent, @code{keymap-parent} returns @code{nil}. | |
404 | @end defun | |
405 | ||
406 | @defun set-keymap-parent keymap parent | |
407 | This sets the parent keymap of @var{keymap} to @var{parent}, and returns | |
408 | @var{parent}. If @var{parent} is @code{nil}, this function gives | |
409 | @var{keymap} no parent at all. | |
410 | ||
411 | If @var{keymap} has submaps (bindings for prefix keys), they too receive | |
412 | new parent keymaps that reflect what @var{parent} specifies for those | |
413 | prefix keys. | |
414 | @end defun | |
415 | ||
416 | Here is an example showing how to make a keymap that inherits | |
417 | from @code{text-mode-map}: | |
418 | ||
419 | @example | |
420 | (let ((map (make-sparse-keymap))) | |
421 | (set-keymap-parent map text-mode-map) | |
422 | map) | |
423 | @end example | |
424 | ||
425 | A non-sparse keymap can have a parent too, but this is not very | |
426 | useful. A non-sparse keymap always specifies something as the binding | |
427 | for every numeric character code without modifier bits, even if it is | |
428 | @code{nil}, so these character's bindings are never inherited from | |
429 | the parent keymap. | |
430 | ||
dac86404 GM |
431 | @cindex keymap inheritance from multiple maps |
432 | Sometimes you want to make a keymap that inherits from more than one | |
433 | map. You can use the function @code{make-composed-keymap} for this. | |
434 | ||
435 | @defun make-composed-keymap maps &optional parent | |
436 | This function returns a new keymap composed of the existing keymap(s) | |
437 | @var{maps}, and optionally inheriting from a parent keymap | |
438 | @var{parent}. @var{maps} can be a single keymap or a list of more | |
439 | than one. When looking up a key in the resulting new map, Emacs | |
3d8badf4 CY |
440 | searches in each of the @var{maps} in turn, and then in @var{parent}, |
441 | stopping at the first match. A @code{nil} binding in any one of | |
442 | @var{maps} overrides any binding in @var{parent}, but it does not | |
443 | override any non-@code{nil} binding in any other of the @var{maps}. | |
dac86404 GM |
444 | @end defun |
445 | ||
446 | @noindent For example, here is how Emacs sets the parent of | |
447 | @code{help-mode-map}, such that it inherits from both | |
448 | @code{button-buffer-map} and @code{special-mode-map}: | |
449 | ||
450 | @example | |
451 | (defvar help-mode-map | |
452 | (let ((map (make-sparse-keymap))) | |
84f4a531 CY |
453 | (set-keymap-parent map |
454 | (make-composed-keymap button-buffer-map special-mode-map)) | |
dac86404 GM |
455 | ... map) ... ) |
456 | @end example | |
457 | ||
458 | ||
b8d4c8d0 GM |
459 | @node Prefix Keys |
460 | @section Prefix Keys | |
461 | @cindex prefix key | |
462 | ||
463 | A @dfn{prefix key} is a key sequence whose binding is a keymap. The | |
464 | keymap defines what to do with key sequences that extend the prefix key. | |
465 | For example, @kbd{C-x} is a prefix key, and it uses a keymap that is | |
466 | also stored in the variable @code{ctl-x-map}. This keymap defines | |
467 | bindings for key sequences starting with @kbd{C-x}. | |
468 | ||
469 | Some of the standard Emacs prefix keys use keymaps that are | |
470 | also found in Lisp variables: | |
471 | ||
472 | @itemize @bullet | |
473 | @item | |
474 | @vindex esc-map | |
475 | @findex ESC-prefix | |
476 | @code{esc-map} is the global keymap for the @key{ESC} prefix key. Thus, | |
477 | the global definitions of all meta characters are actually found here. | |
478 | This map is also the function definition of @code{ESC-prefix}. | |
479 | ||
480 | @item | |
481 | @cindex @kbd{C-h} | |
482 | @code{help-map} is the global keymap for the @kbd{C-h} prefix key. | |
483 | ||
484 | @item | |
485 | @cindex @kbd{C-c} | |
486 | @vindex mode-specific-map | |
487 | @code{mode-specific-map} is the global keymap for the prefix key | |
488 | @kbd{C-c}. This map is actually global, not mode-specific, but its name | |
489 | provides useful information about @kbd{C-c} in the output of @kbd{C-h b} | |
490 | (@code{display-bindings}), since the main use of this prefix key is for | |
491 | mode-specific bindings. | |
492 | ||
493 | @item | |
494 | @cindex @kbd{C-x} | |
495 | @vindex ctl-x-map | |
496 | @findex Control-X-prefix | |
497 | @code{ctl-x-map} is the global keymap used for the @kbd{C-x} prefix key. | |
498 | This map is found via the function cell of the symbol | |
499 | @code{Control-X-prefix}. | |
500 | ||
501 | @item | |
502 | @cindex @kbd{C-x @key{RET}} | |
503 | @vindex mule-keymap | |
504 | @code{mule-keymap} is the global keymap used for the @kbd{C-x @key{RET}} | |
505 | prefix key. | |
506 | ||
507 | @item | |
508 | @cindex @kbd{C-x 4} | |
509 | @vindex ctl-x-4-map | |
510 | @code{ctl-x-4-map} is the global keymap used for the @kbd{C-x 4} prefix | |
511 | key. | |
512 | ||
b8d4c8d0 GM |
513 | @item |
514 | @cindex @kbd{C-x 5} | |
515 | @vindex ctl-x-5-map | |
516 | @code{ctl-x-5-map} is the global keymap used for the @kbd{C-x 5} prefix | |
517 | key. | |
518 | ||
b8d4c8d0 GM |
519 | @item |
520 | @cindex @kbd{C-x 6} | |
521 | @vindex 2C-mode-map | |
522 | @code{2C-mode-map} is the global keymap used for the @kbd{C-x 6} prefix | |
523 | key. | |
524 | ||
525 | @item | |
526 | @cindex @kbd{C-x v} | |
527 | @vindex vc-prefix-map | |
528 | @code{vc-prefix-map} is the global keymap used for the @kbd{C-x v} prefix | |
529 | key. | |
530 | ||
260c0dc1 CY |
531 | @item |
532 | @cindex @kbd{M-g} | |
533 | @vindex goto-map | |
534 | @code{goto-map} is the global keymap used for the @kbd{M-g} prefix | |
535 | key. | |
536 | ||
537 | @item | |
538 | @cindex @kbd{M-s} | |
539 | @vindex search-map | |
540 | @code{search-map} is the global keymap used for the @kbd{M-s} prefix | |
541 | key. | |
542 | ||
b8d4c8d0 GM |
543 | @item |
544 | @cindex @kbd{M-o} | |
545 | @vindex facemenu-keymap | |
546 | @code{facemenu-keymap} is the global keymap used for the @kbd{M-o} | |
547 | prefix key. | |
548 | ||
b8d4c8d0 | 549 | @item |
260c0dc1 CY |
550 | The other Emacs prefix keys are @kbd{C-x @@}, @kbd{C-x a i}, @kbd{C-x |
551 | @key{ESC}} and @kbd{@key{ESC} @key{ESC}}. They use keymaps that have | |
552 | no special names. | |
b8d4c8d0 GM |
553 | @end itemize |
554 | ||
555 | The keymap binding of a prefix key is used for looking up the event | |
556 | that follows the prefix key. (It may instead be a symbol whose function | |
557 | definition is a keymap. The effect is the same, but the symbol serves | |
558 | as a name for the prefix key.) Thus, the binding of @kbd{C-x} is the | |
559 | symbol @code{Control-X-prefix}, whose function cell holds the keymap | |
560 | for @kbd{C-x} commands. (The same keymap is also the value of | |
561 | @code{ctl-x-map}.) | |
562 | ||
563 | Prefix key definitions can appear in any active keymap. The | |
564 | definitions of @kbd{C-c}, @kbd{C-x}, @kbd{C-h} and @key{ESC} as prefix | |
565 | keys appear in the global map, so these prefix keys are always | |
566 | available. Major and minor modes can redefine a key as a prefix by | |
567 | putting a prefix key definition for it in the local map or the minor | |
568 | mode's map. @xref{Active Keymaps}. | |
569 | ||
570 | If a key is defined as a prefix in more than one active map, then its | |
571 | various definitions are in effect merged: the commands defined in the | |
572 | minor mode keymaps come first, followed by those in the local map's | |
573 | prefix definition, and then by those from the global map. | |
574 | ||
575 | In the following example, we make @kbd{C-p} a prefix key in the local | |
576 | keymap, in such a way that @kbd{C-p} is identical to @kbd{C-x}. Then | |
577 | the binding for @kbd{C-p C-f} is the function @code{find-file}, just | |
578 | like @kbd{C-x C-f}. The key sequence @kbd{C-p 6} is not found in any | |
579 | active keymap. | |
580 | ||
581 | @example | |
582 | @group | |
583 | (use-local-map (make-sparse-keymap)) | |
584 | @result{} nil | |
585 | @end group | |
586 | @group | |
587 | (local-set-key "\C-p" ctl-x-map) | |
588 | @result{} nil | |
589 | @end group | |
590 | @group | |
591 | (key-binding "\C-p\C-f") | |
592 | @result{} find-file | |
593 | @end group | |
594 | ||
595 | @group | |
596 | (key-binding "\C-p6") | |
597 | @result{} nil | |
598 | @end group | |
599 | @end example | |
600 | ||
601 | @defun define-prefix-command symbol &optional mapvar prompt | |
602 | @cindex prefix command | |
603 | @anchor{Definition of define-prefix-command} | |
604 | This function prepares @var{symbol} for use as a prefix key's binding: | |
605 | it creates a sparse keymap and stores it as @var{symbol}'s function | |
606 | definition. Subsequently binding a key sequence to @var{symbol} will | |
607 | make that key sequence into a prefix key. The return value is @code{symbol}. | |
608 | ||
609 | This function also sets @var{symbol} as a variable, with the keymap as | |
610 | its value. But if @var{mapvar} is non-@code{nil}, it sets @var{mapvar} | |
611 | as a variable instead. | |
612 | ||
613 | If @var{prompt} is non-@code{nil}, that becomes the overall prompt | |
614 | string for the keymap. The prompt string should be given for menu keymaps | |
615 | (@pxref{Defining Menus}). | |
616 | @end defun | |
617 | ||
618 | @node Active Keymaps | |
619 | @section Active Keymaps | |
620 | @cindex active keymap | |
621 | @cindex global keymap | |
622 | @cindex local keymap | |
623 | ||
624 | Emacs normally contains many keymaps; at any given time, just a few | |
625 | of them are @dfn{active}, meaning that they participate in the | |
626 | interpretation of user input. All the active keymaps are used | |
627 | together to determine what command to execute when a key is entered. | |
628 | ||
629 | Normally the active keymaps are the @code{keymap} property keymap, | |
630 | the keymaps of any enabled minor modes, the current buffer's local | |
631 | keymap, and the global keymap, in that order. Emacs searches for each | |
632 | input key sequence in all these keymaps. @xref{Searching Keymaps}, | |
633 | for more details of this procedure. | |
634 | ||
635 | When the key sequence starts with a mouse event (optionally preceded | |
636 | by a symbolic prefix), the active keymaps are determined based on the | |
637 | position in that event. If the event happened on a string embedded | |
638 | with a @code{display}, @code{before-string}, or @code{after-string} | |
639 | property (@pxref{Special Properties}), the non-@code{nil} map | |
0f2ae894 CY |
640 | properties of the string override those of the buffer (if the |
641 | underlying buffer text contains map properties in its text properties | |
642 | or overlays, they are ignored). | |
b8d4c8d0 GM |
643 | |
644 | The @dfn{global keymap} holds the bindings of keys that are defined | |
645 | regardless of the current buffer, such as @kbd{C-f}. The variable | |
646 | @code{global-map} holds this keymap, which is always active. | |
647 | ||
648 | Each buffer may have another keymap, its @dfn{local keymap}, which | |
649 | may contain new or overriding definitions for keys. The current | |
650 | buffer's local keymap is always active except when | |
651 | @code{overriding-local-map} overrides it. The @code{local-map} text | |
652 | or overlay property can specify an alternative local keymap for certain | |
653 | parts of the buffer; see @ref{Special Properties}. | |
654 | ||
655 | Each minor mode can have a keymap; if it does, the keymap is active | |
656 | when the minor mode is enabled. Modes for emulation can specify | |
657 | additional active keymaps through the variable | |
658 | @code{emulation-mode-map-alists}. | |
659 | ||
660 | The highest precedence normal keymap comes from the @code{keymap} | |
661 | text or overlay property. If that is non-@code{nil}, it is the first | |
662 | keymap to be processed, in normal circumstances. | |
663 | ||
664 | However, there are also special ways for programs to substitute | |
665 | other keymaps for some of those. The variable | |
666 | @code{overriding-local-map}, if non-@code{nil}, specifies a keymap | |
667 | that replaces all the usual active keymaps except the global keymap. | |
668 | Another way to do this is with @code{overriding-terminal-local-map}; | |
669 | it operates on a per-terminal basis. These variables are documented | |
670 | below. | |
671 | ||
672 | @cindex major mode keymap | |
673 | Since every buffer that uses the same major mode normally uses the | |
674 | same local keymap, you can think of the keymap as local to the mode. A | |
675 | change to the local keymap of a buffer (using @code{local-set-key}, for | |
676 | example) is seen also in the other buffers that share that keymap. | |
677 | ||
678 | The local keymaps that are used for Lisp mode and some other major | |
679 | modes exist even if they have not yet been used. These local keymaps are | |
680 | the values of variables such as @code{lisp-mode-map}. For most major | |
681 | modes, which are less frequently used, the local keymap is constructed | |
682 | only when the mode is used for the first time in a session. | |
683 | ||
684 | The minibuffer has local keymaps, too; they contain various completion | |
685 | and exit commands. @xref{Intro to Minibuffers}. | |
686 | ||
687 | Emacs has other keymaps that are used in a different way---translating | |
688 | events within @code{read-key-sequence}. @xref{Translation Keymaps}. | |
689 | ||
53a1239b | 690 | @xref{Standard Keymaps}, for a list of some standard keymaps. |
b8d4c8d0 GM |
691 | |
692 | @defun current-active-maps &optional olp position | |
693 | This returns the list of active keymaps that would be used by the | |
694 | command loop in the current circumstances to look up a key sequence. | |
695 | Normally it ignores @code{overriding-local-map} and | |
696 | @code{overriding-terminal-local-map}, but if @var{olp} is non-@code{nil} | |
697 | then it pays attention to them. @var{position} can optionally be either | |
698 | an event position as returned by @code{event-start} or a buffer | |
699 | position, and may change the keymaps as described for | |
700 | @code{key-binding}. | |
701 | @end defun | |
702 | ||
703 | @defun key-binding key &optional accept-defaults no-remap position | |
704 | This function returns the binding for @var{key} according to the | |
705 | current active keymaps. The result is @code{nil} if @var{key} is | |
706 | undefined in the keymaps. | |
707 | ||
708 | The argument @var{accept-defaults} controls checking for default | |
709 | bindings, as in @code{lookup-key} (@pxref{Functions for Key Lookup}). | |
710 | ||
711 | When commands are remapped (@pxref{Remapping Commands}), | |
712 | @code{key-binding} normally processes command remappings so as to | |
35a30759 | 713 | return the remapped command that will actually be executed. However, |
b8d4c8d0 GM |
714 | if @var{no-remap} is non-@code{nil}, @code{key-binding} ignores |
715 | remappings and returns the binding directly specified for @var{key}. | |
716 | ||
717 | If @var{key} starts with a mouse event (perhaps following a prefix | |
718 | event), the maps to be consulted are determined based on the event's | |
719 | position. Otherwise, they are determined based on the value of point. | |
720 | However, you can override either of them by specifying @var{position}. | |
721 | If @var{position} is non-@code{nil}, it should be either a buffer | |
722 | position or an event position like the value of @code{event-start}. | |
723 | Then the maps consulted are determined based on @var{position}. | |
724 | ||
725 | An error is signaled if @var{key} is not a string or a vector. | |
726 | ||
727 | @example | |
728 | @group | |
729 | (key-binding "\C-x\C-f") | |
730 | @result{} find-file | |
731 | @end group | |
732 | @end example | |
733 | @end defun | |
734 | ||
735 | @node Searching Keymaps | |
736 | @section Searching the Active Keymaps | |
737 | @cindex searching active keymaps for keys | |
738 | ||
739 | After translation of event subsequences (@pxref{Translation | |
740 | Keymaps}) Emacs looks for them in the active keymaps. Here is a | |
741 | pseudo-Lisp description of the order and conditions for searching | |
742 | them: | |
743 | ||
744 | @lisp | |
049bcbcb CY |
745 | (or (cond |
746 | (overriding-terminal-local-map | |
747 | (@var{find-in} overriding-terminal-local-map)) | |
748 | (overriding-local-map | |
749 | (@var{find-in} overriding-local-map)) | |
dfc47e35 CY |
750 | ((or (@var{find-in} (get-char-property (point) 'keymap)) |
751 | (@var{find-in-any} emulation-mode-map-alists) | |
752 | (@var{find-in-any} minor-mode-overriding-map-alist) | |
753 | (@var{find-in-any} minor-mode-map-alist) | |
754 | (if (get-text-property (point) 'local-map) | |
755 | (@var{find-in} (get-char-property (point) 'local-map)) | |
756 | (@var{find-in} (current-local-map)))))) | |
b8d4c8d0 GM |
757 | (@var{find-in} (current-global-map))) |
758 | @end lisp | |
759 | ||
760 | @noindent | |
3d8badf4 CY |
761 | @var{find-in} and @var{find-in-any} are pseudo functions that search |
762 | in one keymap and in an alist of keymaps, respectively. (Searching a | |
763 | single keymap for a binding is called @dfn{key lookup}; see @ref{Key | |
764 | Lookup}.) If the key sequence starts with a mouse event, or a | |
765 | symbolic prefix event followed by a mouse event, that event's position | |
766 | is used instead of point and the current buffer. Mouse events on an | |
767 | embedded string use non-@code{nil} text properties from that string | |
768 | instead of the buffer. | |
769 | ||
770 | When a match is found (@pxref{Key Lookup}), if the binding in the | |
b8d4c8d0 GM |
771 | keymap is a function, the search is over. However if the keymap entry |
772 | is a symbol with a value or a string, Emacs replaces the input key | |
773 | sequences with the variable's value or the string, and restarts the | |
774 | search of the active keymaps. | |
3d8badf4 CY |
775 | |
776 | The function finally found might also be remapped. @xref{Remapping | |
777 | Commands}. | |
b8d4c8d0 GM |
778 | |
779 | @node Controlling Active Maps | |
780 | @section Controlling the Active Keymaps | |
781 | ||
782 | @defvar global-map | |
783 | This variable contains the default global keymap that maps Emacs | |
784 | keyboard input to commands. The global keymap is normally this | |
785 | keymap. The default global keymap is a full keymap that binds | |
786 | @code{self-insert-command} to all of the printing characters. | |
787 | ||
788 | It is normal practice to change the bindings in the global keymap, but you | |
789 | should not assign this variable any value other than the keymap it starts | |
790 | out with. | |
791 | @end defvar | |
792 | ||
793 | @defun current-global-map | |
1ef5eecc ER |
794 | This function returns the current global keymap. This is the same as |
795 | the value of @code{global-map} unless you change one or the other. | |
796 | The return value is a reference, not a copy; if you use | |
797 | @code{define-key} or other functions on it you will alter global | |
798 | bindings. | |
b8d4c8d0 GM |
799 | |
800 | @example | |
801 | @group | |
802 | (current-global-map) | |
803 | @result{} (keymap [set-mark-command beginning-of-line @dots{} | |
804 | delete-backward-char]) | |
805 | @end group | |
806 | @end example | |
807 | @end defun | |
808 | ||
809 | @defun current-local-map | |
810 | This function returns the current buffer's local keymap, or @code{nil} | |
811 | if it has none. In the following example, the keymap for the | |
2bb0eca1 | 812 | @file{*scratch*} buffer (using Lisp Interaction mode) is a sparse keymap |
b8d4c8d0 GM |
813 | in which the entry for @key{ESC}, @acronym{ASCII} code 27, is another sparse |
814 | keymap. | |
815 | ||
816 | @example | |
817 | @group | |
818 | (current-local-map) | |
819 | @result{} (keymap | |
820 | (10 . eval-print-last-sexp) | |
821 | (9 . lisp-indent-line) | |
822 | (127 . backward-delete-char-untabify) | |
823 | @end group | |
824 | @group | |
825 | (27 keymap | |
826 | (24 . eval-defun) | |
827 | (17 . indent-sexp))) | |
828 | @end group | |
829 | @end example | |
830 | @end defun | |
831 | ||
1ef5eecc ER |
832 | @code{current-local-map} returns a reference to the local keymap, not |
833 | a copy of it; if you use @code{define-key} or other functions on it | |
834 | you will alter local bindings. | |
835 | ||
b8d4c8d0 GM |
836 | @defun current-minor-mode-maps |
837 | This function returns a list of the keymaps of currently enabled minor modes. | |
838 | @end defun | |
839 | ||
840 | @defun use-global-map keymap | |
841 | This function makes @var{keymap} the new current global keymap. It | |
842 | returns @code{nil}. | |
843 | ||
844 | It is very unusual to change the global keymap. | |
845 | @end defun | |
846 | ||
847 | @defun use-local-map keymap | |
848 | This function makes @var{keymap} the new local keymap of the current | |
849 | buffer. If @var{keymap} is @code{nil}, then the buffer has no local | |
850 | keymap. @code{use-local-map} returns @code{nil}. Most major mode | |
851 | commands use this function. | |
852 | @end defun | |
853 | ||
854 | @c Emacs 19 feature | |
855 | @defvar minor-mode-map-alist | |
856 | @anchor{Definition of minor-mode-map-alist} | |
857 | This variable is an alist describing keymaps that may or may not be | |
858 | active according to the values of certain variables. Its elements look | |
859 | like this: | |
860 | ||
861 | @example | |
862 | (@var{variable} . @var{keymap}) | |
863 | @end example | |
864 | ||
865 | The keymap @var{keymap} is active whenever @var{variable} has a | |
866 | non-@code{nil} value. Typically @var{variable} is the variable that | |
867 | enables or disables a minor mode. @xref{Keymaps and Minor Modes}. | |
868 | ||
869 | Note that elements of @code{minor-mode-map-alist} do not have the same | |
870 | structure as elements of @code{minor-mode-alist}. The map must be the | |
871 | @sc{cdr} of the element; a list with the map as the second element will | |
872 | not do. The @sc{cdr} can be either a keymap (a list) or a symbol whose | |
873 | function definition is a keymap. | |
874 | ||
875 | When more than one minor mode keymap is active, the earlier one in | |
876 | @code{minor-mode-map-alist} takes priority. But you should design | |
877 | minor modes so that they don't interfere with each other. If you do | |
878 | this properly, the order will not matter. | |
879 | ||
880 | See @ref{Keymaps and Minor Modes}, for more information about minor | |
881 | modes. See also @code{minor-mode-key-binding} (@pxref{Functions for Key | |
882 | Lookup}). | |
883 | @end defvar | |
884 | ||
885 | @defvar minor-mode-overriding-map-alist | |
886 | This variable allows major modes to override the key bindings for | |
887 | particular minor modes. The elements of this alist look like the | |
888 | elements of @code{minor-mode-map-alist}: @code{(@var{variable} | |
889 | . @var{keymap})}. | |
890 | ||
891 | If a variable appears as an element of | |
892 | @code{minor-mode-overriding-map-alist}, the map specified by that | |
893 | element totally replaces any map specified for the same variable in | |
894 | @code{minor-mode-map-alist}. | |
895 | ||
896 | @code{minor-mode-overriding-map-alist} is automatically buffer-local in | |
897 | all buffers. | |
898 | @end defvar | |
899 | ||
900 | @defvar overriding-local-map | |
901 | If non-@code{nil}, this variable holds a keymap to use instead of the | |
902 | buffer's local keymap, any text property or overlay keymaps, and any | |
903 | minor mode keymaps. This keymap, if specified, overrides all other | |
904 | maps that would have been active, except for the current global map. | |
905 | @end defvar | |
906 | ||
907 | @defvar overriding-terminal-local-map | |
908 | If non-@code{nil}, this variable holds a keymap to use instead of | |
909 | @code{overriding-local-map}, the buffer's local keymap, text property | |
910 | or overlay keymaps, and all the minor mode keymaps. | |
911 | ||
912 | This variable is always local to the current terminal and cannot be | |
3ec61d4e | 913 | buffer-local. @xref{Multiple Terminals}. It is used to implement |
b8d4c8d0 GM |
914 | incremental search mode. |
915 | @end defvar | |
916 | ||
917 | @defvar overriding-local-map-menu-flag | |
918 | If this variable is non-@code{nil}, the value of | |
919 | @code{overriding-local-map} or @code{overriding-terminal-local-map} can | |
920 | affect the display of the menu bar. The default value is @code{nil}, so | |
921 | those map variables have no effect on the menu bar. | |
922 | ||
923 | Note that these two map variables do affect the execution of key | |
924 | sequences entered using the menu bar, even if they do not affect the | |
925 | menu bar display. So if a menu bar key sequence comes in, you should | |
926 | clear the variables before looking up and executing that key sequence. | |
927 | Modes that use the variables would typically do this anyway; normally | |
928 | they respond to events that they do not handle by ``unreading'' them and | |
929 | exiting. | |
930 | @end defvar | |
931 | ||
932 | @defvar special-event-map | |
933 | This variable holds a keymap for special events. If an event type has a | |
934 | binding in this keymap, then it is special, and the binding for the | |
935 | event is run directly by @code{read-event}. @xref{Special Events}. | |
936 | @end defvar | |
937 | ||
938 | @defvar emulation-mode-map-alists | |
939 | This variable holds a list of keymap alists to use for emulations | |
940 | modes. It is intended for modes or packages using multiple minor-mode | |
941 | keymaps. Each element is a keymap alist which has the same format and | |
942 | meaning as @code{minor-mode-map-alist}, or a symbol with a variable | |
943 | binding which is such an alist. The ``active'' keymaps in each alist | |
944 | are used before @code{minor-mode-map-alist} and | |
945 | @code{minor-mode-overriding-map-alist}. | |
946 | @end defvar | |
947 | ||
948 | @node Key Lookup | |
949 | @section Key Lookup | |
950 | @cindex key lookup | |
951 | @cindex keymap entry | |
952 | ||
953 | @dfn{Key lookup} is the process of finding the binding of a key | |
954 | sequence from a given keymap. The execution or use of the binding is | |
955 | not part of key lookup. | |
956 | ||
957 | Key lookup uses just the event type of each event in the key sequence; | |
958 | the rest of the event is ignored. In fact, a key sequence used for key | |
959 | lookup may designate a mouse event with just its types (a symbol) | |
960 | instead of the entire event (a list). @xref{Input Events}. Such | |
961 | a ``key sequence'' is insufficient for @code{command-execute} to run, | |
962 | but it is sufficient for looking up or rebinding a key. | |
963 | ||
964 | When the key sequence consists of multiple events, key lookup | |
965 | processes the events sequentially: the binding of the first event is | |
966 | found, and must be a keymap; then the second event's binding is found in | |
967 | that keymap, and so on until all the events in the key sequence are used | |
968 | up. (The binding thus found for the last event may or may not be a | |
969 | keymap.) Thus, the process of key lookup is defined in terms of a | |
970 | simpler process for looking up a single event in a keymap. How that is | |
971 | done depends on the type of object associated with the event in that | |
972 | keymap. | |
973 | ||
974 | Let's use the term @dfn{keymap entry} to describe the value found by | |
975 | looking up an event type in a keymap. (This doesn't include the item | |
976 | string and other extra elements in a keymap element for a menu item, because | |
977 | @code{lookup-key} and other key lookup functions don't include them in | |
978 | the returned value.) While any Lisp object may be stored in a keymap | |
979 | as a keymap entry, not all make sense for key lookup. Here is a table | |
980 | of the meaningful types of keymap entries: | |
981 | ||
982 | @table @asis | |
983 | @item @code{nil} | |
984 | @cindex @code{nil} in keymap | |
985 | @code{nil} means that the events used so far in the lookup form an | |
986 | undefined key. When a keymap fails to mention an event type at all, and | |
987 | has no default binding, that is equivalent to a binding of @code{nil} | |
988 | for that event type. | |
989 | ||
990 | @item @var{command} | |
991 | @cindex command in keymap | |
992 | The events used so far in the lookup form a complete key, | |
993 | and @var{command} is its binding. @xref{What Is a Function}. | |
994 | ||
995 | @item @var{array} | |
996 | @cindex string in keymap | |
997 | The array (either a string or a vector) is a keyboard macro. The events | |
998 | used so far in the lookup form a complete key, and the array is its | |
999 | binding. See @ref{Keyboard Macros}, for more information. | |
1000 | ||
1001 | @item @var{keymap} | |
1002 | @cindex keymap in keymap | |
1003 | The events used so far in the lookup form a prefix key. The next | |
1004 | event of the key sequence is looked up in @var{keymap}. | |
1005 | ||
1006 | @item @var{list} | |
1007 | @cindex list in keymap | |
1008 | The meaning of a list depends on what it contains: | |
1009 | ||
1010 | @itemize @bullet | |
1011 | @item | |
1012 | If the @sc{car} of @var{list} is the symbol @code{keymap}, then the list | |
1013 | is a keymap, and is treated as a keymap (see above). | |
1014 | ||
1015 | @item | |
1016 | @cindex @code{lambda} in keymap | |
1017 | If the @sc{car} of @var{list} is @code{lambda}, then the list is a | |
1018 | lambda expression. This is presumed to be a function, and is treated | |
1019 | as such (see above). In order to execute properly as a key binding, | |
1020 | this function must be a command---it must have an @code{interactive} | |
1021 | specification. @xref{Defining Commands}. | |
1022 | ||
1023 | @item | |
1024 | If the @sc{car} of @var{list} is a keymap and the @sc{cdr} is an event | |
1025 | type, then this is an @dfn{indirect entry}: | |
1026 | ||
1027 | @example | |
1028 | (@var{othermap} . @var{othertype}) | |
1029 | @end example | |
1030 | ||
1031 | When key lookup encounters an indirect entry, it looks up instead the | |
1032 | binding of @var{othertype} in @var{othermap} and uses that. | |
1033 | ||
1034 | This feature permits you to define one key as an alias for another key. | |
1035 | For example, an entry whose @sc{car} is the keymap called @code{esc-map} | |
1036 | and whose @sc{cdr} is 32 (the code for @key{SPC}) means, ``Use the global | |
16152b76 | 1037 | binding of @kbd{Meta-@key{SPC}}, whatever that may be''. |
b8d4c8d0 GM |
1038 | @end itemize |
1039 | ||
1040 | @item @var{symbol} | |
1041 | @cindex symbol in keymap | |
1042 | The function definition of @var{symbol} is used in place of | |
1043 | @var{symbol}. If that too is a symbol, then this process is repeated, | |
1044 | any number of times. Ultimately this should lead to an object that is | |
1045 | a keymap, a command, or a keyboard macro. A list is allowed if it is a | |
1046 | keymap or a command, but indirect entries are not understood when found | |
1047 | via symbols. | |
1048 | ||
1049 | Note that keymaps and keyboard macros (strings and vectors) are not | |
1050 | valid functions, so a symbol with a keymap, string, or vector as its | |
1051 | function definition is invalid as a function. It is, however, valid as | |
1052 | a key binding. If the definition is a keyboard macro, then the symbol | |
1053 | is also valid as an argument to @code{command-execute} | |
1054 | (@pxref{Interactive Call}). | |
1055 | ||
1056 | @cindex @code{undefined} in keymap | |
1057 | The symbol @code{undefined} is worth special mention: it means to treat | |
1058 | the key as undefined. Strictly speaking, the key is defined, and its | |
1059 | binding is the command @code{undefined}; but that command does the same | |
1060 | thing that is done automatically for an undefined key: it rings the bell | |
1061 | (by calling @code{ding}) but does not signal an error. | |
1062 | ||
1063 | @cindex preventing prefix key | |
1064 | @code{undefined} is used in local keymaps to override a global key | |
1065 | binding and make the key ``undefined'' locally. A local binding of | |
1066 | @code{nil} would fail to do this because it would not override the | |
1067 | global binding. | |
1068 | ||
1069 | @item @var{anything else} | |
1070 | If any other type of object is found, the events used so far in the | |
1071 | lookup form a complete key, and the object is its binding, but the | |
1072 | binding is not executable as a command. | |
1073 | @end table | |
1074 | ||
3d8badf4 CY |
1075 | In short, a keymap entry may be a keymap, a command, a keyboard |
1076 | macro, a symbol that leads to one of them, or an indirection or | |
1077 | @code{nil}. | |
b8d4c8d0 GM |
1078 | |
1079 | @node Functions for Key Lookup | |
1080 | @section Functions for Key Lookup | |
1081 | ||
1082 | Here are the functions and variables pertaining to key lookup. | |
1083 | ||
1084 | @defun lookup-key keymap key &optional accept-defaults | |
1085 | This function returns the definition of @var{key} in @var{keymap}. All | |
1086 | the other functions described in this chapter that look up keys use | |
1087 | @code{lookup-key}. Here are examples: | |
1088 | ||
1089 | @example | |
1090 | @group | |
1091 | (lookup-key (current-global-map) "\C-x\C-f") | |
1092 | @result{} find-file | |
1093 | @end group | |
1094 | @group | |
1095 | (lookup-key (current-global-map) (kbd "C-x C-f")) | |
1096 | @result{} find-file | |
1097 | @end group | |
1098 | @group | |
1099 | (lookup-key (current-global-map) "\C-x\C-f12345") | |
1100 | @result{} 2 | |
1101 | @end group | |
1102 | @end example | |
1103 | ||
1104 | If the string or vector @var{key} is not a valid key sequence according | |
1105 | to the prefix keys specified in @var{keymap}, it must be ``too long'' | |
1106 | and have extra events at the end that do not fit into a single key | |
1107 | sequence. Then the value is a number, the number of events at the front | |
1108 | of @var{key} that compose a complete key. | |
1109 | ||
1110 | @c Emacs 19 feature | |
1111 | If @var{accept-defaults} is non-@code{nil}, then @code{lookup-key} | |
1112 | considers default bindings as well as bindings for the specific events | |
1113 | in @var{key}. Otherwise, @code{lookup-key} reports only bindings for | |
1114 | the specific sequence @var{key}, ignoring default bindings except when | |
1115 | you explicitly ask about them. (To do this, supply @code{t} as an | |
1116 | element of @var{key}; see @ref{Format of Keymaps}.) | |
1117 | ||
1118 | If @var{key} contains a meta character (not a function key), that | |
1119 | character is implicitly replaced by a two-character sequence: the value | |
1120 | of @code{meta-prefix-char}, followed by the corresponding non-meta | |
1121 | character. Thus, the first example below is handled by conversion into | |
1122 | the second example. | |
1123 | ||
1124 | @example | |
1125 | @group | |
1126 | (lookup-key (current-global-map) "\M-f") | |
1127 | @result{} forward-word | |
1128 | @end group | |
1129 | @group | |
1130 | (lookup-key (current-global-map) "\ef") | |
1131 | @result{} forward-word | |
1132 | @end group | |
1133 | @end example | |
1134 | ||
1135 | Unlike @code{read-key-sequence}, this function does not modify the | |
1136 | specified events in ways that discard information (@pxref{Key Sequence | |
1137 | Input}). In particular, it does not convert letters to lower case and | |
1138 | it does not change drag events to clicks. | |
1139 | @end defun | |
1140 | ||
1141 | @deffn Command undefined | |
1142 | Used in keymaps to undefine keys. It calls @code{ding}, but does | |
1143 | not cause an error. | |
1144 | @end deffn | |
1145 | ||
1146 | @defun local-key-binding key &optional accept-defaults | |
1147 | This function returns the binding for @var{key} in the current | |
1148 | local keymap, or @code{nil} if it is undefined there. | |
1149 | ||
1150 | @c Emacs 19 feature | |
1151 | The argument @var{accept-defaults} controls checking for default bindings, | |
1152 | as in @code{lookup-key} (above). | |
1153 | @end defun | |
1154 | ||
1155 | @defun global-key-binding key &optional accept-defaults | |
1156 | This function returns the binding for command @var{key} in the | |
1157 | current global keymap, or @code{nil} if it is undefined there. | |
1158 | ||
1159 | @c Emacs 19 feature | |
1160 | The argument @var{accept-defaults} controls checking for default bindings, | |
1161 | as in @code{lookup-key} (above). | |
1162 | @end defun | |
1163 | ||
1164 | @c Emacs 19 feature | |
1165 | @defun minor-mode-key-binding key &optional accept-defaults | |
1166 | This function returns a list of all the active minor mode bindings of | |
1167 | @var{key}. More precisely, it returns an alist of pairs | |
1168 | @code{(@var{modename} . @var{binding})}, where @var{modename} is the | |
1169 | variable that enables the minor mode, and @var{binding} is @var{key}'s | |
1170 | binding in that mode. If @var{key} has no minor-mode bindings, the | |
1171 | value is @code{nil}. | |
1172 | ||
1173 | If the first binding found is not a prefix definition (a keymap or a | |
1174 | symbol defined as a keymap), all subsequent bindings from other minor | |
1175 | modes are omitted, since they would be completely shadowed. Similarly, | |
1176 | the list omits non-prefix bindings that follow prefix bindings. | |
1177 | ||
1178 | The argument @var{accept-defaults} controls checking for default | |
1179 | bindings, as in @code{lookup-key} (above). | |
1180 | @end defun | |
1181 | ||
01f17ae2 | 1182 | @defopt meta-prefix-char |
b8d4c8d0 GM |
1183 | @cindex @key{ESC} |
1184 | This variable is the meta-prefix character code. It is used for | |
1185 | translating a meta character to a two-character sequence so it can be | |
1186 | looked up in a keymap. For useful results, the value should be a | |
1187 | prefix event (@pxref{Prefix Keys}). The default value is 27, which is | |
1188 | the @acronym{ASCII} code for @key{ESC}. | |
1189 | ||
1190 | As long as the value of @code{meta-prefix-char} remains 27, key lookup | |
1191 | translates @kbd{M-b} into @kbd{@key{ESC} b}, which is normally defined | |
1192 | as the @code{backward-word} command. However, if you were to set | |
1193 | @code{meta-prefix-char} to 24, the code for @kbd{C-x}, then Emacs will | |
1194 | translate @kbd{M-b} into @kbd{C-x b}, whose standard binding is the | |
1195 | @code{switch-to-buffer} command. (Don't actually do this!) Here is an | |
1196 | illustration of what would happen: | |
1197 | ||
1198 | @smallexample | |
1199 | @group | |
1200 | meta-prefix-char ; @r{The default value.} | |
1201 | @result{} 27 | |
1202 | @end group | |
1203 | @group | |
1204 | (key-binding "\M-b") | |
1205 | @result{} backward-word | |
1206 | @end group | |
1207 | @group | |
1208 | ?\C-x ; @r{The print representation} | |
1209 | @result{} 24 ; @r{of a character.} | |
1210 | @end group | |
1211 | @group | |
1212 | (setq meta-prefix-char 24) | |
1213 | @result{} 24 | |
1214 | @end group | |
1215 | @group | |
1216 | (key-binding "\M-b") | |
1217 | @result{} switch-to-buffer ; @r{Now, typing @kbd{M-b} is} | |
1218 | ; @r{like typing @kbd{C-x b}.} | |
1219 | ||
1220 | (setq meta-prefix-char 27) ; @r{Avoid confusion!} | |
1221 | @result{} 27 ; @r{Restore the default value!} | |
1222 | @end group | |
1223 | @end smallexample | |
1224 | ||
1225 | This translation of one event into two happens only for characters, not | |
1226 | for other kinds of input events. Thus, @kbd{M-@key{F1}}, a function | |
1227 | key, is not converted into @kbd{@key{ESC} @key{F1}}. | |
01f17ae2 | 1228 | @end defopt |
b8d4c8d0 GM |
1229 | |
1230 | @node Changing Key Bindings | |
1231 | @section Changing Key Bindings | |
1232 | @cindex changing key bindings | |
1233 | @cindex rebinding | |
1234 | ||
1235 | The way to rebind a key is to change its entry in a keymap. If you | |
1236 | change a binding in the global keymap, the change is effective in all | |
1237 | buffers (though it has no direct effect in buffers that shadow the | |
1238 | global binding with a local one). If you change the current buffer's | |
1239 | local map, that usually affects all buffers using the same major mode. | |
1240 | The @code{global-set-key} and @code{local-set-key} functions are | |
1241 | convenient interfaces for these operations (@pxref{Key Binding | |
1242 | Commands}). You can also use @code{define-key}, a more general | |
35a30759 | 1243 | function; then you must explicitly specify the map to change. |
b8d4c8d0 GM |
1244 | |
1245 | When choosing the key sequences for Lisp programs to rebind, please | |
1246 | follow the Emacs conventions for use of various keys (@pxref{Key | |
1247 | Binding Conventions}). | |
1248 | ||
1249 | @cindex meta character key constants | |
1250 | @cindex control character key constants | |
1251 | In writing the key sequence to rebind, it is good to use the special | |
1252 | escape sequences for control and meta characters (@pxref{String Type}). | |
1253 | The syntax @samp{\C-} means that the following character is a control | |
1254 | character and @samp{\M-} means that the following character is a meta | |
1255 | character. Thus, the string @code{"\M-x"} is read as containing a | |
1256 | single @kbd{M-x}, @code{"\C-f"} is read as containing a single | |
1257 | @kbd{C-f}, and @code{"\M-\C-x"} and @code{"\C-\M-x"} are both read as | |
1258 | containing a single @kbd{C-M-x}. You can also use this escape syntax in | |
1259 | vectors, as well as others that aren't allowed in strings; one example | |
1260 | is @samp{[?\C-\H-x home]}. @xref{Character Type}. | |
1261 | ||
1262 | The key definition and lookup functions accept an alternate syntax for | |
1263 | event types in a key sequence that is a vector: you can use a list | |
1264 | containing modifier names plus one base event (a character or function | |
1265 | key name). For example, @code{(control ?a)} is equivalent to | |
1266 | @code{?\C-a} and @code{(hyper control left)} is equivalent to | |
1267 | @code{C-H-left}. One advantage of such lists is that the precise | |
1268 | numeric codes for the modifier bits don't appear in compiled files. | |
1269 | ||
1270 | The functions below signal an error if @var{keymap} is not a keymap, | |
1271 | or if @var{key} is not a string or vector representing a key sequence. | |
1272 | You can use event types (symbols) as shorthand for events that are | |
1273 | lists. The @code{kbd} macro (@pxref{Key Sequences}) is a convenient | |
1274 | way to specify the key sequence. | |
1275 | ||
1276 | @defun define-key keymap key binding | |
1277 | This function sets the binding for @var{key} in @var{keymap}. (If | |
1278 | @var{key} is more than one event long, the change is actually made | |
1279 | in another keymap reached from @var{keymap}.) The argument | |
1280 | @var{binding} can be any Lisp object, but only certain types are | |
1281 | meaningful. (For a list of meaningful types, see @ref{Key Lookup}.) | |
1282 | The value returned by @code{define-key} is @var{binding}. | |
1283 | ||
1284 | If @var{key} is @code{[t]}, this sets the default binding in | |
1285 | @var{keymap}. When an event has no binding of its own, the Emacs | |
1286 | command loop uses the keymap's default binding, if there is one. | |
1287 | ||
1288 | @cindex invalid prefix key error | |
1289 | @cindex key sequence error | |
1290 | Every prefix of @var{key} must be a prefix key (i.e., bound to a keymap) | |
1291 | or undefined; otherwise an error is signaled. If some prefix of | |
1292 | @var{key} is undefined, then @code{define-key} defines it as a prefix | |
1293 | key so that the rest of @var{key} can be defined as specified. | |
1294 | ||
1295 | If there was previously no binding for @var{key} in @var{keymap}, the | |
1296 | new binding is added at the beginning of @var{keymap}. The order of | |
1297 | bindings in a keymap makes no difference for keyboard input, but it | |
1298 | does matter for menu keymaps (@pxref{Menu Keymaps}). | |
1299 | @end defun | |
1300 | ||
1301 | This example creates a sparse keymap and makes a number of | |
1302 | bindings in it: | |
1303 | ||
1304 | @smallexample | |
1305 | @group | |
1306 | (setq map (make-sparse-keymap)) | |
1307 | @result{} (keymap) | |
1308 | @end group | |
1309 | @group | |
1310 | (define-key map "\C-f" 'forward-char) | |
1311 | @result{} forward-char | |
1312 | @end group | |
1313 | @group | |
1314 | map | |
1315 | @result{} (keymap (6 . forward-char)) | |
1316 | @end group | |
1317 | ||
1318 | @group | |
1319 | ;; @r{Build sparse submap for @kbd{C-x} and bind @kbd{f} in that.} | |
1320 | (define-key map (kbd "C-x f") 'forward-word) | |
1321 | @result{} forward-word | |
1322 | @end group | |
1323 | @group | |
1324 | map | |
1325 | @result{} (keymap | |
1326 | (24 keymap ; @kbd{C-x} | |
1327 | (102 . forward-word)) ; @kbd{f} | |
1328 | (6 . forward-char)) ; @kbd{C-f} | |
1329 | @end group | |
1330 | ||
1331 | @group | |
1332 | ;; @r{Bind @kbd{C-p} to the @code{ctl-x-map}.} | |
1333 | (define-key map (kbd "C-p") ctl-x-map) | |
1334 | ;; @code{ctl-x-map} | |
1335 | @result{} [nil @dots{} find-file @dots{} backward-kill-sentence] | |
1336 | @end group | |
1337 | ||
1338 | @group | |
1339 | ;; @r{Bind @kbd{C-f} to @code{foo} in the @code{ctl-x-map}.} | |
1340 | (define-key map (kbd "C-p C-f") 'foo) | |
1341 | @result{} 'foo | |
1342 | @end group | |
1343 | @group | |
1344 | map | |
1345 | @result{} (keymap ; @r{Note @code{foo} in @code{ctl-x-map}.} | |
1346 | (16 keymap [nil @dots{} foo @dots{} backward-kill-sentence]) | |
1347 | (24 keymap | |
1348 | (102 . forward-word)) | |
1349 | (6 . forward-char)) | |
1350 | @end group | |
1351 | @end smallexample | |
1352 | ||
1353 | @noindent | |
1354 | Note that storing a new binding for @kbd{C-p C-f} actually works by | |
1355 | changing an entry in @code{ctl-x-map}, and this has the effect of | |
1356 | changing the bindings of both @kbd{C-p C-f} and @kbd{C-x C-f} in the | |
1357 | default global map. | |
1358 | ||
1359 | The function @code{substitute-key-definition} scans a keymap for | |
1360 | keys that have a certain binding and rebinds them with a different | |
1361 | binding. Another feature which is cleaner and can often produce the | |
1362 | same results to remap one command into another (@pxref{Remapping | |
1363 | Commands}). | |
1364 | ||
1365 | @defun substitute-key-definition olddef newdef keymap &optional oldmap | |
1366 | @cindex replace bindings | |
1367 | This function replaces @var{olddef} with @var{newdef} for any keys in | |
1368 | @var{keymap} that were bound to @var{olddef}. In other words, | |
1369 | @var{olddef} is replaced with @var{newdef} wherever it appears. The | |
1370 | function returns @code{nil}. | |
1371 | ||
1372 | For example, this redefines @kbd{C-x C-f}, if you do it in an Emacs with | |
1373 | standard bindings: | |
1374 | ||
1375 | @smallexample | |
1376 | @group | |
1377 | (substitute-key-definition | |
1378 | 'find-file 'find-file-read-only (current-global-map)) | |
1379 | @end group | |
1380 | @end smallexample | |
1381 | ||
1382 | @c Emacs 19 feature | |
1383 | If @var{oldmap} is non-@code{nil}, that changes the behavior of | |
1384 | @code{substitute-key-definition}: the bindings in @var{oldmap} determine | |
1385 | which keys to rebind. The rebindings still happen in @var{keymap}, not | |
1386 | in @var{oldmap}. Thus, you can change one map under the control of the | |
1387 | bindings in another. For example, | |
1388 | ||
1389 | @smallexample | |
1390 | (substitute-key-definition | |
1391 | 'delete-backward-char 'my-funny-delete | |
1392 | my-map global-map) | |
1393 | @end smallexample | |
1394 | ||
1395 | @noindent | |
1396 | puts the special deletion command in @code{my-map} for whichever keys | |
1397 | are globally bound to the standard deletion command. | |
1398 | ||
1399 | Here is an example showing a keymap before and after substitution: | |
1400 | ||
1401 | @smallexample | |
1402 | @group | |
1403 | (setq map '(keymap | |
1404 | (?1 . olddef-1) | |
1405 | (?2 . olddef-2) | |
1406 | (?3 . olddef-1))) | |
1407 | @result{} (keymap (49 . olddef-1) (50 . olddef-2) (51 . olddef-1)) | |
1408 | @end group | |
1409 | ||
1410 | @group | |
1411 | (substitute-key-definition 'olddef-1 'newdef map) | |
1412 | @result{} nil | |
1413 | @end group | |
1414 | @group | |
1415 | map | |
1416 | @result{} (keymap (49 . newdef) (50 . olddef-2) (51 . newdef)) | |
1417 | @end group | |
1418 | @end smallexample | |
1419 | @end defun | |
1420 | ||
1421 | @defun suppress-keymap keymap &optional nodigits | |
1422 | @cindex @code{self-insert-command} override | |
1423 | This function changes the contents of the full keymap @var{keymap} by | |
1424 | remapping @code{self-insert-command} to the command @code{undefined} | |
1425 | (@pxref{Remapping Commands}). This has the effect of undefining all | |
1426 | printing characters, thus making ordinary insertion of text impossible. | |
1427 | @code{suppress-keymap} returns @code{nil}. | |
1428 | ||
1429 | If @var{nodigits} is @code{nil}, then @code{suppress-keymap} defines | |
1430 | digits to run @code{digit-argument}, and @kbd{-} to run | |
1431 | @code{negative-argument}. Otherwise it makes them undefined like the | |
1432 | rest of the printing characters. | |
1433 | ||
1434 | @cindex yank suppression | |
1435 | @cindex @code{quoted-insert} suppression | |
1436 | The @code{suppress-keymap} function does not make it impossible to | |
1437 | modify a buffer, as it does not suppress commands such as @code{yank} | |
1438 | and @code{quoted-insert}. To prevent any modification of a buffer, make | |
1439 | it read-only (@pxref{Read Only Buffers}). | |
1440 | ||
1441 | Since this function modifies @var{keymap}, you would normally use it | |
1442 | on a newly created keymap. Operating on an existing keymap | |
1443 | that is used for some other purpose is likely to cause trouble; for | |
1444 | example, suppressing @code{global-map} would make it impossible to use | |
1445 | most of Emacs. | |
1446 | ||
3d8badf4 CY |
1447 | This function can be used to initialize the local keymap of a major |
1448 | mode for which insertion of text is not desirable. But usually such a | |
1449 | mode should be derived from @code{special-mode} (@pxref{Basic Major | |
1450 | Modes}); then its keymap will automatically inherit from | |
1451 | @code{special-mode-map}, which is already suppressed. Here is how | |
1452 | @code{special-mode-map} is defined: | |
b8d4c8d0 GM |
1453 | |
1454 | @smallexample | |
1455 | @group | |
3d8badf4 CY |
1456 | (defvar special-mode-map |
1457 | (let ((map (make-sparse-keymap))) | |
1458 | (suppress-keymap map) | |
1459 | (define-key map "q" 'quit-window) | |
1460 | @dots{} | |
1461 | map)) | |
b8d4c8d0 GM |
1462 | @end group |
1463 | @end smallexample | |
1464 | @end defun | |
1465 | ||
1466 | @node Remapping Commands | |
1467 | @section Remapping Commands | |
1468 | @cindex remapping commands | |
1469 | ||
58539c63 CY |
1470 | A special kind of key binding can be used to @dfn{remap} one command |
1471 | to another, without having to refer to the key sequence(s) bound to | |
1472 | the original command. To use this feature, make a key binding for a | |
1473 | key sequence that starts with the dummy event @code{remap}, followed | |
1474 | by the command name you want to remap; for the binding, specify the | |
1475 | new definition (usually a command name, but possibly any other valid | |
1476 | definition for a key binding). | |
1477 | ||
1478 | For example, suppose My mode provides a special command | |
1479 | @code{my-kill-line}, which should be invoked instead of | |
1480 | @code{kill-line}. To establish this, its mode keymap should contain | |
1481 | the following remapping: | |
b8d4c8d0 GM |
1482 | |
1483 | @smallexample | |
1484 | (define-key my-mode-map [remap kill-line] 'my-kill-line) | |
b8d4c8d0 GM |
1485 | @end smallexample |
1486 | ||
58539c63 CY |
1487 | @noindent |
1488 | Then, whenever @code{my-mode-map} is active, if the user types | |
1489 | @kbd{C-k} (the default global key sequence for @code{kill-line}) Emacs | |
1490 | will instead run @code{my-kill-line}. | |
b8d4c8d0 | 1491 | |
58539c63 CY |
1492 | Note that remapping only takes place through active keymaps; for |
1493 | example, putting a remapping in a prefix keymap like @code{ctl-x-map} | |
1494 | typically has no effect, as such keymaps are not themselves active. | |
1495 | In addition, remapping only works through a single level; in the | |
1496 | following example, | |
b8d4c8d0 GM |
1497 | |
1498 | @smallexample | |
1499 | (define-key my-mode-map [remap kill-line] 'my-kill-line) | |
1500 | (define-key my-mode-map [remap my-kill-line] 'my-other-kill-line) | |
1501 | @end smallexample | |
1502 | ||
1503 | @noindent | |
58539c63 CY |
1504 | @code{kill-line} is @emph{not} remapped to @code{my-other-kill-line}. |
1505 | Instead, if an ordinary key binding specifies @code{kill-line}, it is | |
1506 | remapped to @code{my-kill-line}; if an ordinary binding specifies | |
1507 | @code{my-kill-line}, it is remapped to @code{my-other-kill-line}. | |
b8d4c8d0 | 1508 | |
dff9ac46 GM |
1509 | To undo the remapping of a command, remap it to @code{nil}; e.g. |
1510 | ||
1511 | @smallexample | |
1512 | (define-key my-mode-map [remap kill-line] nil) | |
1513 | @end smallexample | |
1514 | ||
b8d4c8d0 GM |
1515 | @defun command-remapping command &optional position keymaps |
1516 | This function returns the remapping for @var{command} (a symbol), | |
1517 | given the current active keymaps. If @var{command} is not remapped | |
1518 | (which is the usual situation), or not a symbol, the function returns | |
1519 | @code{nil}. @code{position} can optionally specify a buffer position | |
1520 | or an event position to determine the keymaps to use, as in | |
1521 | @code{key-binding}. | |
1522 | ||
1523 | If the optional argument @code{keymaps} is non-@code{nil}, it | |
1524 | specifies a list of keymaps to search in. This argument is ignored if | |
1525 | @code{position} is non-@code{nil}. | |
1526 | @end defun | |
1527 | ||
1528 | @node Translation Keymaps | |
1529 | @section Keymaps for Translating Sequences of Events | |
1530 | @cindex keymaps for translating events | |
1531 | ||
1532 | This section describes keymaps that are used during reading a key | |
1533 | sequence, to translate certain event sequences into others. | |
1534 | @code{read-key-sequence} checks every subsequence of the key sequence | |
4f4a84ec | 1535 | being read, as it is read, against @code{input-decode-map}, then |
6b9e7694 | 1536 | @code{local-function-key-map}, and then against @code{key-translation-map}. |
4f4a84ec SM |
1537 | |
1538 | @defvar input-decode-map | |
b8d4c8d0 GM |
1539 | This variable holds a keymap that describes the character sequences sent |
1540 | by function keys on an ordinary character terminal. This keymap has the | |
1541 | same structure as other keymaps, but is used differently: it specifies | |
1542 | translations to make while reading key sequences, rather than bindings | |
1543 | for key sequences. | |
1544 | ||
4f4a84ec | 1545 | If @code{input-decode-map} ``binds'' a key sequence @var{k} to a vector |
b8d4c8d0 GM |
1546 | @var{v}, then when @var{k} appears as a subsequence @emph{anywhere} in a |
1547 | key sequence, it is replaced with the events in @var{v}. | |
1548 | ||
1549 | For example, VT100 terminals send @kbd{@key{ESC} O P} when the | |
1550 | keypad @key{PF1} key is pressed. Therefore, we want Emacs to translate | |
1551 | that sequence of events into the single event @code{pf1}. We accomplish | |
1552 | this by ``binding'' @kbd{@key{ESC} O P} to @code{[pf1]} in | |
4f4a84ec | 1553 | @code{input-decode-map}, when using a VT100. |
b8d4c8d0 GM |
1554 | |
1555 | Thus, typing @kbd{C-c @key{PF1}} sends the character sequence @kbd{C-c | |
1556 | @key{ESC} O P}; later the function @code{read-key-sequence} translates | |
1557 | this back into @kbd{C-c @key{PF1}}, which it returns as the vector | |
1558 | @code{[?\C-c pf1]}. | |
1559 | ||
4f4a84ec | 1560 | The value of @code{input-decode-map} is usually set up automatically |
b8d4c8d0 GM |
1561 | according to the terminal's Terminfo or Termcap entry, but sometimes |
1562 | those need help from terminal-specific Lisp files. Emacs comes with | |
1563 | terminal-specific files for many common terminals; their main purpose is | |
4f4a84ec | 1564 | to make entries in @code{input-decode-map} beyond those that can be |
b8d4c8d0 GM |
1565 | deduced from Termcap and Terminfo. @xref{Terminal-Specific}. |
1566 | @end defvar | |
1567 | ||
6b9e7694 | 1568 | @defvar local-function-key-map |
4f4a84ec SM |
1569 | This variable holds a keymap similar to @code{input-decode-map} except |
1570 | that it describes key sequences which should be translated to | |
1571 | alternative interpretations that are usually preferred. It applies | |
1572 | after @code{input-decode-map} and before @code{key-translation-map}. | |
b8d4c8d0 | 1573 | |
6b9e7694 EZ |
1574 | Entries in @code{local-function-key-map} are ignored if they conflict |
1575 | with bindings made in the minor mode, local, or global keymaps. I.e. | |
4f4a84ec SM |
1576 | the remapping only applies if the original key sequence would |
1577 | otherwise not have any binding. | |
6b9e7694 EZ |
1578 | |
1579 | @code{local-function-key-map} inherits from @code{function-key-map}, | |
1580 | but the latter should not be used directly. | |
4f4a84ec | 1581 | @end defvar |
b8d4c8d0 | 1582 | |
4f4a84ec SM |
1583 | @defvar key-translation-map |
1584 | This variable is another keymap used just like @code{input-decode-map} | |
1585 | to translate input events into other events. It differs from | |
1586 | @code{input-decode-map} in that it goes to work after | |
6b9e7694 EZ |
1587 | @code{local-function-key-map} is finished rather than before; it |
1588 | receives the results of translation by @code{local-function-key-map}. | |
1589 | ||
1590 | Just like @code{input-decode-map}, but unlike | |
1591 | @code{local-function-key-map}, this keymap is applied regardless of | |
1592 | whether the input key-sequence has a normal binding. Note however | |
1593 | that actual key bindings can have an effect on | |
1594 | @code{key-translation-map}, even though they are overridden by it. | |
1595 | Indeed, actual key bindings override @code{local-function-key-map} and | |
1596 | thus may alter the key sequence that @code{key-translation-map} | |
1597 | receives. Clearly, it is better to avoid this type of situation. | |
b8d4c8d0 GM |
1598 | |
1599 | The intent of @code{key-translation-map} is for users to map one | |
1600 | character set to another, including ordinary characters normally bound | |
1601 | to @code{self-insert-command}. | |
1602 | @end defvar | |
1603 | ||
1604 | @cindex key translation function | |
84f4a531 CY |
1605 | You can use @code{input-decode-map}, @code{local-function-key-map}, |
1606 | and @code{key-translation-map} for more than simple aliases, by using | |
1607 | a function, instead of a key sequence, as the ``translation'' of a | |
1608 | key. Then this function is called to compute the translation of that | |
1609 | key. | |
b8d4c8d0 GM |
1610 | |
1611 | The key translation function receives one argument, which is the prompt | |
1612 | that was specified in @code{read-key-sequence}---or @code{nil} if the | |
1613 | key sequence is being read by the editor command loop. In most cases | |
1614 | you can ignore the prompt value. | |
1615 | ||
1616 | If the function reads input itself, it can have the effect of altering | |
1617 | the event that follows. For example, here's how to define @kbd{C-c h} | |
1618 | to turn the character that follows into a Hyper character: | |
1619 | ||
1620 | @example | |
1621 | @group | |
1622 | (defun hyperify (prompt) | |
1623 | (let ((e (read-event))) | |
1624 | (vector (if (numberp e) | |
1625 | (logior (lsh 1 24) e) | |
1626 | (if (memq 'hyper (event-modifiers e)) | |
1627 | e | |
1628 | (add-event-modifier "H-" e)))))) | |
1629 | ||
1630 | (defun add-event-modifier (string e) | |
1631 | (let ((symbol (if (symbolp e) e (car e)))) | |
1632 | (setq symbol (intern (concat string | |
1633 | (symbol-name symbol)))) | |
1634 | @end group | |
1635 | @group | |
1636 | (if (symbolp e) | |
1637 | symbol | |
1638 | (cons symbol (cdr e))))) | |
1639 | ||
6b9e7694 | 1640 | (define-key local-function-key-map "\C-ch" 'hyperify) |
b8d4c8d0 GM |
1641 | @end group |
1642 | @end example | |
1643 | ||
1644 | If you have enabled keyboard character set decoding using | |
1645 | @code{set-keyboard-coding-system}, decoding is done after the | |
1646 | translations listed above. @xref{Terminal I/O Encoding}. However, in | |
1647 | future Emacs versions, character set decoding may be done at an | |
1648 | earlier stage. | |
1649 | ||
1650 | @node Key Binding Commands | |
1651 | @section Commands for Binding Keys | |
1652 | ||
1653 | This section describes some convenient interactive interfaces for | |
1654 | changing key bindings. They work by calling @code{define-key}. | |
1655 | ||
1656 | People often use @code{global-set-key} in their init files | |
1657 | (@pxref{Init File}) for simple customization. For example, | |
1658 | ||
1659 | @smallexample | |
1660 | (global-set-key (kbd "C-x C-\\") 'next-line) | |
1661 | @end smallexample | |
1662 | ||
1663 | @noindent | |
1664 | or | |
1665 | ||
1666 | @smallexample | |
1667 | (global-set-key [?\C-x ?\C-\\] 'next-line) | |
1668 | @end smallexample | |
1669 | ||
1670 | @noindent | |
1671 | or | |
1672 | ||
1673 | @smallexample | |
1674 | (global-set-key [(control ?x) (control ?\\)] 'next-line) | |
1675 | @end smallexample | |
1676 | ||
1677 | @noindent | |
1678 | redefines @kbd{C-x C-\} to move down a line. | |
1679 | ||
1680 | @smallexample | |
1681 | (global-set-key [M-mouse-1] 'mouse-set-point) | |
1682 | @end smallexample | |
1683 | ||
1684 | @noindent | |
1685 | redefines the first (leftmost) mouse button, entered with the Meta key, to | |
1686 | set point where you click. | |
1687 | ||
1688 | @cindex non-@acronym{ASCII} text in keybindings | |
1689 | Be careful when using non-@acronym{ASCII} text characters in Lisp | |
1690 | specifications of keys to bind. If these are read as multibyte text, as | |
1691 | they usually will be in a Lisp file (@pxref{Loading Non-ASCII}), you | |
1692 | must type the keys as multibyte too. For instance, if you use this: | |
1693 | ||
1694 | @smallexample | |
1695 | (global-set-key "@"o" 'my-function) ; bind o-umlaut | |
1696 | @end smallexample | |
1697 | ||
1698 | @noindent | |
1699 | or | |
1700 | ||
1701 | @smallexample | |
1702 | (global-set-key ?@"o 'my-function) ; bind o-umlaut | |
1703 | @end smallexample | |
1704 | ||
1705 | @noindent | |
1706 | and your language environment is multibyte Latin-1, these commands | |
e4021ec1 SM |
1707 | actually bind the multibyte character with code 246, not the byte |
1708 | code 246 (@kbd{M-v}) sent by a Latin-1 terminal. In order to use this | |
1709 | binding, you need to teach Emacs how to decode the keyboard by using an | |
1710 | appropriate input method (@pxref{Input Methods, , Input Methods, emacs, The GNU | |
1711 | Emacs Manual}). | |
b8d4c8d0 GM |
1712 | |
1713 | @deffn Command global-set-key key binding | |
1714 | This function sets the binding of @var{key} in the current global map | |
1715 | to @var{binding}. | |
1716 | ||
1717 | @smallexample | |
1718 | @group | |
1719 | (global-set-key @var{key} @var{binding}) | |
1720 | @equiv{} | |
1721 | (define-key (current-global-map) @var{key} @var{binding}) | |
1722 | @end group | |
1723 | @end smallexample | |
1724 | @end deffn | |
1725 | ||
1726 | @deffn Command global-unset-key key | |
1727 | @cindex unbinding keys | |
1728 | This function removes the binding of @var{key} from the current | |
1729 | global map. | |
1730 | ||
1731 | One use of this function is in preparation for defining a longer key | |
1732 | that uses @var{key} as a prefix---which would not be allowed if | |
1733 | @var{key} has a non-prefix binding. For example: | |
1734 | ||
1735 | @smallexample | |
1736 | @group | |
1737 | (global-unset-key "\C-l") | |
1738 | @result{} nil | |
1739 | @end group | |
1740 | @group | |
1741 | (global-set-key "\C-l\C-l" 'redraw-display) | |
1742 | @result{} nil | |
1743 | @end group | |
1744 | @end smallexample | |
1745 | ||
1746 | This function is implemented simply using @code{define-key}: | |
1747 | ||
1748 | @smallexample | |
1749 | @group | |
1750 | (global-unset-key @var{key}) | |
1751 | @equiv{} | |
1752 | (define-key (current-global-map) @var{key} nil) | |
1753 | @end group | |
1754 | @end smallexample | |
1755 | @end deffn | |
1756 | ||
1757 | @deffn Command local-set-key key binding | |
1758 | This function sets the binding of @var{key} in the current local | |
1759 | keymap to @var{binding}. | |
1760 | ||
1761 | @smallexample | |
1762 | @group | |
1763 | (local-set-key @var{key} @var{binding}) | |
1764 | @equiv{} | |
1765 | (define-key (current-local-map) @var{key} @var{binding}) | |
1766 | @end group | |
1767 | @end smallexample | |
1768 | @end deffn | |
1769 | ||
1770 | @deffn Command local-unset-key key | |
1771 | This function removes the binding of @var{key} from the current | |
1772 | local map. | |
1773 | ||
1774 | @smallexample | |
1775 | @group | |
1776 | (local-unset-key @var{key}) | |
1777 | @equiv{} | |
1778 | (define-key (current-local-map) @var{key} nil) | |
1779 | @end group | |
1780 | @end smallexample | |
1781 | @end deffn | |
1782 | ||
1783 | @node Scanning Keymaps | |
1784 | @section Scanning Keymaps | |
1785 | ||
1786 | This section describes functions used to scan all the current keymaps | |
1787 | for the sake of printing help information. | |
1788 | ||
1789 | @defun accessible-keymaps keymap &optional prefix | |
1790 | This function returns a list of all the keymaps that can be reached (via | |
1791 | zero or more prefix keys) from @var{keymap}. The value is an | |
1792 | association list with elements of the form @code{(@var{key} .@: | |
1793 | @var{map})}, where @var{key} is a prefix key whose definition in | |
1794 | @var{keymap} is @var{map}. | |
1795 | ||
1796 | The elements of the alist are ordered so that the @var{key} increases | |
1797 | in length. The first element is always @code{([] .@: @var{keymap})}, | |
1798 | because the specified keymap is accessible from itself with a prefix of | |
1799 | no events. | |
1800 | ||
1801 | If @var{prefix} is given, it should be a prefix key sequence; then | |
1802 | @code{accessible-keymaps} includes only the submaps whose prefixes start | |
1803 | with @var{prefix}. These elements look just as they do in the value of | |
1804 | @code{(accessible-keymaps)}; the only difference is that some elements | |
1805 | are omitted. | |
1806 | ||
1807 | In the example below, the returned alist indicates that the key | |
1808 | @key{ESC}, which is displayed as @samp{^[}, is a prefix key whose | |
1809 | definition is the sparse keymap @code{(keymap (83 .@: center-paragraph) | |
1810 | (115 .@: foo))}. | |
1811 | ||
1812 | @smallexample | |
1813 | @group | |
1814 | (accessible-keymaps (current-local-map)) | |
1815 | @result{}(([] keymap | |
1816 | (27 keymap ; @r{Note this keymap for @key{ESC} is repeated below.} | |
1817 | (83 . center-paragraph) | |
1818 | (115 . center-line)) | |
1819 | (9 . tab-to-tab-stop)) | |
1820 | @end group | |
1821 | ||
1822 | @group | |
1823 | ("^[" keymap | |
1824 | (83 . center-paragraph) | |
1825 | (115 . foo))) | |
1826 | @end group | |
1827 | @end smallexample | |
1828 | ||
1829 | In the following example, @kbd{C-h} is a prefix key that uses a sparse | |
1830 | keymap starting with @code{(keymap (118 . describe-variable)@dots{})}. | |
1831 | Another prefix, @kbd{C-x 4}, uses a keymap which is also the value of | |
1832 | the variable @code{ctl-x-4-map}. The event @code{mode-line} is one of | |
1833 | several dummy events used as prefixes for mouse actions in special parts | |
1834 | of a window. | |
1835 | ||
1836 | @smallexample | |
1837 | @group | |
1838 | (accessible-keymaps (current-global-map)) | |
1839 | @result{} (([] keymap [set-mark-command beginning-of-line @dots{} | |
1840 | delete-backward-char]) | |
1841 | @end group | |
1842 | @group | |
1843 | ("^H" keymap (118 . describe-variable) @dots{} | |
1844 | (8 . help-for-help)) | |
1845 | @end group | |
1846 | @group | |
1847 | ("^X" keymap [x-flush-mouse-queue @dots{} | |
1848 | backward-kill-sentence]) | |
1849 | @end group | |
1850 | @group | |
1851 | ("^[" keymap [mark-sexp backward-sexp @dots{} | |
1852 | backward-kill-word]) | |
1853 | @end group | |
1854 | ("^X4" keymap (15 . display-buffer) @dots{}) | |
1855 | @group | |
1856 | ([mode-line] keymap | |
1857 | (S-mouse-2 . mouse-split-window-horizontally) @dots{})) | |
1858 | @end group | |
1859 | @end smallexample | |
1860 | ||
1861 | @noindent | |
1862 | These are not all the keymaps you would see in actuality. | |
1863 | @end defun | |
1864 | ||
1865 | @defun map-keymap function keymap | |
1866 | The function @code{map-keymap} calls @var{function} once | |
1867 | for each binding in @var{keymap}. It passes two arguments, | |
1868 | the event type and the value of the binding. If @var{keymap} | |
1869 | has a parent, the parent's bindings are included as well. | |
1870 | This works recursively: if the parent has itself a parent, then the | |
1871 | grandparent's bindings are also included and so on. | |
1872 | ||
1873 | This function is the cleanest way to examine all the bindings | |
1874 | in a keymap. | |
1875 | @end defun | |
1876 | ||
1877 | @defun where-is-internal command &optional keymap firstonly noindirect no-remap | |
1878 | This function is a subroutine used by the @code{where-is} command | |
1879 | (@pxref{Help, , Help, emacs,The GNU Emacs Manual}). It returns a list | |
1880 | of all key sequences (of any length) that are bound to @var{command} in a | |
1881 | set of keymaps. | |
1882 | ||
1883 | The argument @var{command} can be any object; it is compared with all | |
1884 | keymap entries using @code{eq}. | |
1885 | ||
1886 | If @var{keymap} is @code{nil}, then the maps used are the current active | |
1887 | keymaps, disregarding @code{overriding-local-map} (that is, pretending | |
1888 | its value is @code{nil}). If @var{keymap} is a keymap, then the | |
1889 | maps searched are @var{keymap} and the global keymap. If @var{keymap} | |
1890 | is a list of keymaps, only those keymaps are searched. | |
1891 | ||
1892 | Usually it's best to use @code{overriding-local-map} as the expression | |
775ab395 CY |
1893 | for @var{keymap}. Then @code{where-is-internal} searches precisely |
1894 | the keymaps that are active. To search only the global map, pass the | |
1895 | value @code{(keymap)} (an empty keymap) as @var{keymap}. | |
b8d4c8d0 GM |
1896 | |
1897 | If @var{firstonly} is @code{non-ascii}, then the value is a single | |
1898 | vector representing the first key sequence found, rather than a list of | |
1899 | all possible key sequences. If @var{firstonly} is @code{t}, then the | |
1900 | value is the first key sequence, except that key sequences consisting | |
1901 | entirely of @acronym{ASCII} characters (or meta variants of @acronym{ASCII} | |
1902 | characters) are preferred to all other key sequences and that the | |
1903 | return value can never be a menu binding. | |
1904 | ||
1905 | If @var{noindirect} is non-@code{nil}, @code{where-is-internal} doesn't | |
1906 | follow indirect keymap bindings. This makes it possible to search for | |
1907 | an indirect definition itself. | |
1908 | ||
775ab395 CY |
1909 | The fifth argument, @var{no-remap}, determines how this function |
1910 | treats command remappings (@pxref{Remapping Commands}). There are two | |
1911 | cases of interest: | |
b8d4c8d0 | 1912 | |
775ab395 CY |
1913 | @table @asis |
1914 | @item If a command @var{other-command} is remapped to @var{command}: | |
1915 | If @var{no-remap} is @code{nil}, find the bindings for | |
1916 | @var{other-command} and treat them as though they are also bindings | |
1917 | for @var{command}. If @var{no-remap} is non-@code{nil}, include the | |
1918 | vector @code{[remap @var{other-command}]} in the list of possible key | |
1919 | sequences, instead of finding those bindings. | |
1920 | ||
1921 | @item If @var{command} is remapped to @var{other-command}: | |
1922 | If @var{no-remap} is @code{nil}, return the bindings for | |
1923 | @var{other-command} rather than @var{command}. If @var{no-remap} is | |
1924 | non-@code{nil}, return the bindings for @var{command}, ignoring the | |
1925 | fact that it is remapped. | |
1926 | @end table | |
b8d4c8d0 GM |
1927 | @end defun |
1928 | ||
1929 | @deffn Command describe-bindings &optional prefix buffer-or-name | |
1930 | This function creates a listing of all current key bindings, and | |
2bb0eca1 | 1931 | displays it in a buffer named @file{*Help*}. The text is grouped by |
b8d4c8d0 GM |
1932 | modes---minor modes first, then the major mode, then global bindings. |
1933 | ||
1934 | If @var{prefix} is non-@code{nil}, it should be a prefix key; then the | |
1935 | listing includes only keys that start with @var{prefix}. | |
1936 | ||
1937 | The listing describes meta characters as @key{ESC} followed by the | |
1938 | corresponding non-meta character. | |
1939 | ||
1940 | When several characters with consecutive @acronym{ASCII} codes have the | |
1941 | same definition, they are shown together, as | |
1942 | @samp{@var{firstchar}..@var{lastchar}}. In this instance, you need to | |
1943 | know the @acronym{ASCII} codes to understand which characters this means. | |
1944 | For example, in the default global map, the characters @samp{@key{SPC} | |
1945 | ..@: ~} are described by a single line. @key{SPC} is @acronym{ASCII} 32, | |
1946 | @kbd{~} is @acronym{ASCII} 126, and the characters between them include all | |
1947 | the normal printing characters, (e.g., letters, digits, punctuation, | |
1948 | etc.@:); all these characters are bound to @code{self-insert-command}. | |
1949 | ||
1950 | If @var{buffer-or-name} is non-@code{nil}, it should be a buffer or a | |
1951 | buffer name. Then @code{describe-bindings} lists that buffer's bindings, | |
1952 | instead of the current buffer's. | |
1953 | @end deffn | |
1954 | ||
1955 | @node Menu Keymaps | |
1956 | @section Menu Keymaps | |
1957 | @cindex menu keymaps | |
1958 | ||
1959 | A keymap can operate as a menu as well as defining bindings for | |
1960 | keyboard keys and mouse buttons. Menus are usually actuated with the | |
1961 | mouse, but they can function with the keyboard also. If a menu keymap | |
1962 | is active for the next input event, that activates the keyboard menu | |
1963 | feature. | |
1964 | ||
1965 | @menu | |
d24880de GM |
1966 | * Defining Menus:: How to make a keymap that defines a menu. |
1967 | * Mouse Menus:: How users actuate the menu with the mouse. | |
1968 | * Keyboard Menus:: How users actuate the menu with the keyboard. | |
1969 | * Menu Example:: Making a simple menu. | |
1970 | * Menu Bar:: How to customize the menu bar. | |
b8d4c8d0 GM |
1971 | * Tool Bar:: A tool bar is a row of images. |
1972 | * Modifying Menus:: How to add new items to a menu. | |
1973 | @end menu | |
1974 | ||
1975 | @node Defining Menus | |
1976 | @subsection Defining Menus | |
1977 | @cindex defining menus | |
1978 | @cindex menu prompt string | |
1979 | @cindex prompt string (of menu) | |
7427eb97 | 1980 | @cindex menu item |
b8d4c8d0 GM |
1981 | |
1982 | A keymap acts as a menu if it has an @dfn{overall prompt string}, | |
1983 | which is a string that appears as an element of the keymap. | |
1984 | (@xref{Format of Keymaps}.) The string should describe the purpose of | |
1985 | the menu's commands. Emacs displays the overall prompt string as the | |
1986 | menu title in some cases, depending on the toolkit (if any) used for | |
1987 | displaying menus.@footnote{It is required for menus which do not use a | |
1988 | toolkit, e.g.@: under MS-DOS.} Keyboard menus also display the | |
1989 | overall prompt string. | |
1990 | ||
1991 | The easiest way to construct a keymap with a prompt string is to | |
1992 | specify the string as an argument when you call @code{make-keymap}, | |
1993 | @code{make-sparse-keymap} (@pxref{Creating Keymaps}), or | |
1994 | @code{define-prefix-command} (@pxref{Definition of | |
1995 | define-prefix-command}). If you do not want the keymap to operate as | |
1996 | a menu, don't specify a prompt string for it. | |
1997 | ||
1998 | @defun keymap-prompt keymap | |
1999 | This function returns the overall prompt string of @var{keymap}, | |
2000 | or @code{nil} if it has none. | |
2001 | @end defun | |
2002 | ||
2003 | The menu's items are the bindings in the keymap. Each binding | |
2004 | associates an event type to a definition, but the event types have no | |
2005 | significance for the menu appearance. (Usually we use pseudo-events, | |
2006 | symbols that the keyboard cannot generate, as the event types for menu | |
2007 | item bindings.) The menu is generated entirely from the bindings that | |
2008 | correspond in the keymap to these events. | |
2009 | ||
2010 | The order of items in the menu is the same as the order of bindings in | |
2011 | the keymap. Since @code{define-key} puts new bindings at the front, you | |
2012 | should define the menu items starting at the bottom of the menu and | |
2013 | moving to the top, if you care about the order. When you add an item to | |
2014 | an existing menu, you can specify its position in the menu using | |
2015 | @code{define-key-after} (@pxref{Modifying Menus}). | |
2016 | ||
2017 | @menu | |
2018 | * Simple Menu Items:: A simple kind of menu key binding, | |
2019 | limited in capabilities. | |
2020 | * Extended Menu Items:: More powerful menu item definitions | |
2021 | let you specify keywords to enable | |
2022 | various features. | |
2023 | * Menu Separators:: Drawing a horizontal line through a menu. | |
2024 | * Alias Menu Items:: Using command aliases in menu items. | |
011b0ad6 | 2025 | * Toolkit Differences:: Not all toolkits provide the same features. |
b8d4c8d0 GM |
2026 | @end menu |
2027 | ||
011b0ad6 | 2028 | |
b8d4c8d0 GM |
2029 | @node Simple Menu Items |
2030 | @subsubsection Simple Menu Items | |
2031 | ||
2032 | The simpler (and original) way to define a menu item is to bind some | |
2033 | event type (it doesn't matter what event type) to a binding like this: | |
2034 | ||
2035 | @example | |
2036 | (@var{item-string} . @var{real-binding}) | |
2037 | @end example | |
2038 | ||
2039 | @noindent | |
2040 | The @sc{car}, @var{item-string}, is the string to be displayed in the | |
2041 | menu. It should be short---preferably one to three words. It should | |
3d8badf4 CY |
2042 | describe the action of the command it corresponds to. Note that not |
2043 | all graphical toolkits can display non-@acronym{ASCII} text in menus | |
2044 | (it will work for keyboard menus and will work to a large extent with | |
2045 | the GTK+ toolkit). | |
b8d4c8d0 GM |
2046 | |
2047 | You can also supply a second string, called the help string, as follows: | |
2048 | ||
2049 | @example | |
2050 | (@var{item-string} @var{help} . @var{real-binding}) | |
2051 | @end example | |
2052 | ||
2053 | @noindent | |
2054 | @var{help} specifies a ``help-echo'' string to display while the mouse | |
2055 | is on that item in the same way as @code{help-echo} text properties | |
2056 | (@pxref{Help display}). | |
2057 | ||
2058 | As far as @code{define-key} is concerned, @var{item-string} and | |
2059 | @var{help-string} are part of the event's binding. However, | |
2060 | @code{lookup-key} returns just @var{real-binding}, and only | |
2061 | @var{real-binding} is used for executing the key. | |
2062 | ||
2063 | If @var{real-binding} is @code{nil}, then @var{item-string} appears in | |
2064 | the menu but cannot be selected. | |
2065 | ||
2066 | If @var{real-binding} is a symbol and has a non-@code{nil} | |
2067 | @code{menu-enable} property, that property is an expression that | |
2068 | controls whether the menu item is enabled. Every time the keymap is | |
2069 | used to display a menu, Emacs evaluates the expression, and it enables | |
2070 | the menu item only if the expression's value is non-@code{nil}. When a | |
2071 | menu item is disabled, it is displayed in a ``fuzzy'' fashion, and | |
2072 | cannot be selected. | |
2073 | ||
2074 | The menu bar does not recalculate which items are enabled every time you | |
2075 | look at a menu. This is because the X toolkit requires the whole tree | |
2076 | of menus in advance. To force recalculation of the menu bar, call | |
2077 | @code{force-mode-line-update} (@pxref{Mode Line Format}). | |
2078 | ||
b8d4c8d0 GM |
2079 | @node Extended Menu Items |
2080 | @subsubsection Extended Menu Items | |
2081 | @kindex menu-item | |
7427eb97 | 2082 | @cindex extended menu item |
b8d4c8d0 GM |
2083 | |
2084 | An extended-format menu item is a more flexible and also cleaner | |
2085 | alternative to the simple format. You define an event type with a | |
2086 | binding that's a list starting with the symbol @code{menu-item}. | |
2087 | For a non-selectable string, the binding looks like this: | |
2088 | ||
2089 | @example | |
2090 | (menu-item @var{item-name}) | |
2091 | @end example | |
2092 | ||
2093 | @noindent | |
2094 | A string starting with two or more dashes specifies a separator line; | |
2095 | see @ref{Menu Separators}. | |
2096 | ||
2097 | To define a real menu item which can be selected, the extended format | |
2098 | binding looks like this: | |
2099 | ||
2100 | @example | |
2101 | (menu-item @var{item-name} @var{real-binding} | |
2102 | . @var{item-property-list}) | |
2103 | @end example | |
2104 | ||
2105 | @noindent | |
2106 | Here, @var{item-name} is an expression which evaluates to the menu item | |
2107 | string. Thus, the string need not be a constant. The third element, | |
2108 | @var{real-binding}, is the command to execute. The tail of the list, | |
2109 | @var{item-property-list}, has the form of a property list which contains | |
2110 | other information. | |
2111 | ||
b8d4c8d0 GM |
2112 | Here is a table of the properties that are supported: |
2113 | ||
2114 | @table @code | |
2115 | @item :enable @var{form} | |
2116 | The result of evaluating @var{form} determines whether the item is | |
2117 | enabled (non-@code{nil} means yes). If the item is not enabled, | |
2118 | you can't really click on it. | |
2119 | ||
2120 | @item :visible @var{form} | |
2121 | The result of evaluating @var{form} determines whether the item should | |
2122 | actually appear in the menu (non-@code{nil} means yes). If the item | |
2123 | does not appear, then the menu is displayed as if this item were | |
2124 | not defined at all. | |
2125 | ||
2126 | @item :help @var{help} | |
2127 | The value of this property, @var{help}, specifies a ``help-echo'' string | |
2128 | to display while the mouse is on that item. This is displayed in the | |
2129 | same way as @code{help-echo} text properties (@pxref{Help display}). | |
2130 | Note that this must be a constant string, unlike the @code{help-echo} | |
2131 | property for text and overlays. | |
2132 | ||
2133 | @item :button (@var{type} . @var{selected}) | |
2134 | This property provides a way to define radio buttons and toggle buttons. | |
2135 | The @sc{car}, @var{type}, says which: it should be @code{:toggle} or | |
2136 | @code{:radio}. The @sc{cdr}, @var{selected}, should be a form; the | |
2137 | result of evaluating it says whether this button is currently selected. | |
2138 | ||
2139 | A @dfn{toggle} is a menu item which is labeled as either ``on'' or ``off'' | |
2140 | according to the value of @var{selected}. The command itself should | |
2141 | toggle @var{selected}, setting it to @code{t} if it is @code{nil}, | |
2142 | and to @code{nil} if it is @code{t}. Here is how the menu item | |
2143 | to toggle the @code{debug-on-error} flag is defined: | |
2144 | ||
2145 | @example | |
2146 | (menu-item "Debug on Error" toggle-debug-on-error | |
2147 | :button (:toggle | |
2148 | . (and (boundp 'debug-on-error) | |
2149 | debug-on-error))) | |
2150 | @end example | |
2151 | ||
2152 | @noindent | |
2153 | This works because @code{toggle-debug-on-error} is defined as a command | |
2154 | which toggles the variable @code{debug-on-error}. | |
2155 | ||
2156 | @dfn{Radio buttons} are a group of menu items, in which at any time one | |
16152b76 | 2157 | and only one is ``selected''. There should be a variable whose value |
b8d4c8d0 GM |
2158 | says which one is selected at any time. The @var{selected} form for |
2159 | each radio button in the group should check whether the variable has the | |
2160 | right value for selecting that button. Clicking on the button should | |
2161 | set the variable so that the button you clicked on becomes selected. | |
2162 | ||
2163 | @item :key-sequence @var{key-sequence} | |
2164 | This property specifies which key sequence is likely to be bound to the | |
2165 | same command invoked by this menu item. If you specify the right key | |
2166 | sequence, that makes preparing the menu for display run much faster. | |
2167 | ||
2168 | If you specify the wrong key sequence, it has no effect; before Emacs | |
2169 | displays @var{key-sequence} in the menu, it verifies that | |
2170 | @var{key-sequence} is really equivalent to this menu item. | |
2171 | ||
2172 | @item :key-sequence nil | |
2173 | This property indicates that there is normally no key binding which is | |
2174 | equivalent to this menu item. Using this property saves time in | |
2175 | preparing the menu for display, because Emacs does not need to search | |
2176 | the keymaps for a keyboard equivalent for this menu item. | |
2177 | ||
2178 | However, if the user has rebound this item's definition to a key | |
2179 | sequence, Emacs ignores the @code{:keys} property and finds the keyboard | |
2180 | equivalent anyway. | |
2181 | ||
2182 | @item :keys @var{string} | |
2183 | This property specifies that @var{string} is the string to display | |
2184 | as the keyboard equivalent for this menu item. You can use | |
2185 | the @samp{\\[...]} documentation construct in @var{string}. | |
2186 | ||
2187 | @item :filter @var{filter-fn} | |
2188 | This property provides a way to compute the menu item dynamically. | |
2189 | The property value @var{filter-fn} should be a function of one argument; | |
2190 | when it is called, its argument will be @var{real-binding}. The | |
2191 | function should return the binding to use instead. | |
2192 | ||
2193 | Emacs can call this function at any time that it does redisplay or | |
2194 | operates on menu data structures, so you should write it so it can | |
2195 | safely be called at any time. | |
2196 | @end table | |
2197 | ||
2198 | @node Menu Separators | |
2199 | @subsubsection Menu Separators | |
2200 | @cindex menu separators | |
2201 | ||
2202 | A menu separator is a kind of menu item that doesn't display any | |
2203 | text---instead, it divides the menu into subparts with a horizontal line. | |
2204 | A separator looks like this in the menu keymap: | |
2205 | ||
2206 | @example | |
2207 | (menu-item @var{separator-type}) | |
2208 | @end example | |
2209 | ||
2210 | @noindent | |
2211 | where @var{separator-type} is a string starting with two or more dashes. | |
2212 | ||
2213 | In the simplest case, @var{separator-type} consists of only dashes. | |
2214 | That specifies the default kind of separator. (For compatibility, | |
2215 | @code{""} and @code{-} also count as separators.) | |
2216 | ||
2217 | Certain other values of @var{separator-type} specify a different | |
2218 | style of separator. Here is a table of them: | |
2219 | ||
2220 | @table @code | |
2221 | @item "--no-line" | |
2222 | @itemx "--space" | |
2223 | An extra vertical space, with no actual line. | |
2224 | ||
2225 | @item "--single-line" | |
2226 | A single line in the menu's foreground color. | |
2227 | ||
2228 | @item "--double-line" | |
2229 | A double line in the menu's foreground color. | |
2230 | ||
2231 | @item "--single-dashed-line" | |
2232 | A single dashed line in the menu's foreground color. | |
2233 | ||
2234 | @item "--double-dashed-line" | |
2235 | A double dashed line in the menu's foreground color. | |
2236 | ||
2237 | @item "--shadow-etched-in" | |
2238 | A single line with a 3D sunken appearance. This is the default, | |
2239 | used separators consisting of dashes only. | |
2240 | ||
2241 | @item "--shadow-etched-out" | |
2242 | A single line with a 3D raised appearance. | |
2243 | ||
2244 | @item "--shadow-etched-in-dash" | |
2245 | A single dashed line with a 3D sunken appearance. | |
2246 | ||
2247 | @item "--shadow-etched-out-dash" | |
2248 | A single dashed line with a 3D raised appearance. | |
2249 | ||
2250 | @item "--shadow-double-etched-in" | |
2251 | Two lines with a 3D sunken appearance. | |
2252 | ||
2253 | @item "--shadow-double-etched-out" | |
2254 | Two lines with a 3D raised appearance. | |
2255 | ||
2256 | @item "--shadow-double-etched-in-dash" | |
2257 | Two dashed lines with a 3D sunken appearance. | |
2258 | ||
2259 | @item "--shadow-double-etched-out-dash" | |
2260 | Two dashed lines with a 3D raised appearance. | |
2261 | @end table | |
2262 | ||
2263 | You can also give these names in another style, adding a colon after | |
2264 | the double-dash and replacing each single dash with capitalization of | |
2265 | the following word. Thus, @code{"--:singleLine"}, is equivalent to | |
2266 | @code{"--single-line"}. | |
2267 | ||
0bc59b25 LMI |
2268 | You can use a longer form to specify keywords such as @code{:enable} |
2269 | and @code{:visible} for a menu separator: | |
2270 | ||
2271 | @code{(menu-item @var{separator-type} nil . @var{item-property-list})} | |
2272 | ||
2273 | For example: | |
2274 | ||
2275 | @example | |
2276 | (menu-item "--" nil :visible (boundp 'foo)) | |
2277 | @end example | |
2278 | ||
b8d4c8d0 GM |
2279 | Some systems and display toolkits don't really handle all of these |
2280 | separator types. If you use a type that isn't supported, the menu | |
2281 | displays a similar kind of separator that is supported. | |
2282 | ||
2283 | @node Alias Menu Items | |
2284 | @subsubsection Alias Menu Items | |
2285 | ||
2286 | Sometimes it is useful to make menu items that use the ``same'' | |
2287 | command but with different enable conditions. The best way to do this | |
2288 | in Emacs now is with extended menu items; before that feature existed, | |
2289 | it could be done by defining alias commands and using them in menu | |
2290 | items. Here's an example that makes two aliases for | |
2291 | @code{toggle-read-only} and gives them different enable conditions: | |
2292 | ||
2293 | @example | |
2294 | (defalias 'make-read-only 'toggle-read-only) | |
2295 | (put 'make-read-only 'menu-enable '(not buffer-read-only)) | |
2296 | (defalias 'make-writable 'toggle-read-only) | |
2297 | (put 'make-writable 'menu-enable 'buffer-read-only) | |
2298 | @end example | |
2299 | ||
2300 | When using aliases in menus, often it is useful to display the | |
2301 | equivalent key bindings for the ``real'' command name, not the aliases | |
2302 | (which typically don't have any key bindings except for the menu | |
2303 | itself). To request this, give the alias symbol a non-@code{nil} | |
2304 | @code{menu-alias} property. Thus, | |
2305 | ||
2306 | @example | |
2307 | (put 'make-read-only 'menu-alias t) | |
2308 | (put 'make-writable 'menu-alias t) | |
2309 | @end example | |
2310 | ||
2311 | @noindent | |
2312 | causes menu items for @code{make-read-only} and @code{make-writable} to | |
2313 | show the keyboard bindings for @code{toggle-read-only}. | |
2314 | ||
011b0ad6 LMI |
2315 | @node Toolkit Differences |
2316 | @subsubsection Toolkit Differences | |
2317 | ||
2318 | The various toolkits with which you can build Emacs do not all support | |
2319 | the same set of features for menus. Some code works as expected with | |
2320 | one toolkit, but not under another. | |
2321 | ||
b737198d | 2322 | One example is menu actions or buttons in a top-level menu bar. The |
011b0ad6 LMI |
2323 | following works with the Lucid toolkit or on MS Windows, but not with |
2324 | GTK or Nextstep, where clicking on the item has no effect. | |
2325 | ||
2326 | @example | |
2327 | (defun menu-action-greet () | |
2328 | (interactive) | |
2329 | (message "Hello Emacs User!")) | |
2330 | ||
2331 | (defun top-level-menu () | |
2332 | (interactive) | |
2333 | (define-key lisp-interaction-mode-map [menu-bar m] | |
2334 | '(menu-item "Action Button" menu-action-greet))) | |
2335 | @end example | |
2336 | ||
b8d4c8d0 GM |
2337 | @node Mouse Menus |
2338 | @subsection Menus and the Mouse | |
2339 | ||
2340 | The usual way to make a menu keymap produce a menu is to make it the | |
2341 | definition of a prefix key. (A Lisp program can explicitly pop up a | |
2342 | menu and receive the user's choice---see @ref{Pop-Up Menus}.) | |
2343 | ||
2344 | If the prefix key ends with a mouse event, Emacs handles the menu keymap | |
2345 | by popping up a visible menu, so that the user can select a choice with | |
2346 | the mouse. When the user clicks on a menu item, the event generated is | |
2347 | whatever character or symbol has the binding that brought about that | |
2348 | menu item. (A menu item may generate a series of events if the menu has | |
2349 | multiple levels or comes from the menu bar.) | |
2350 | ||
2351 | It's often best to use a button-down event to trigger the menu. Then | |
2352 | the user can select a menu item by releasing the button. | |
2353 | ||
83ef8187 CY |
2354 | @cindex submenu |
2355 | If the menu keymap contains a binding to a nested keymap, the nested | |
2356 | keymap specifies a @dfn{submenu}. There will be a menu item, labeled | |
2357 | by the nested keymap's item string, and clicking on this item | |
2358 | automatically pops up the specified submenu. As a special exception, | |
2359 | if the menu keymap contains a single nested keymap and no other menu | |
2360 | items, the menu shows the contents of the nested keymap directly, not | |
2361 | as a submenu. | |
2362 | ||
2363 | However, if Emacs is compiled without X toolkit support, submenus | |
2364 | are not supported. Each nested keymap is shown as a menu item, but | |
2365 | clicking on it does not automatically pop up the submenu. If you wish | |
2366 | to imitate the effect of submenus, you can do that by giving a nested | |
2367 | keymap an item string which starts with @samp{@@}. This causes Emacs | |
2368 | to display the nested keymap using a separate @dfn{menu pane}; the | |
2369 | rest of the item string after the @samp{@@} is the pane label. If | |
2370 | Emacs is compiled without X toolkit support, menu panes are not used; | |
2371 | in that case, a @samp{@@} at the beginning of an item string is | |
2372 | omitted when the menu label is displayed, and has no other effect. | |
b8d4c8d0 GM |
2373 | |
2374 | @node Keyboard Menus | |
2375 | @subsection Menus and the Keyboard | |
2376 | ||
2377 | When a prefix key ending with a keyboard event (a character or | |
2378 | function key) has a definition that is a menu keymap, the keymap | |
2379 | operates as a keyboard menu; the user specifies the next event by | |
2380 | choosing a menu item with the keyboard. | |
2381 | ||
2382 | Emacs displays the keyboard menu with the map's overall prompt | |
2383 | string, followed by the alternatives (the item strings of the map's | |
2384 | bindings), in the echo area. If the bindings don't all fit at once, | |
2385 | the user can type @key{SPC} to see the next line of alternatives. | |
2386 | Successive uses of @key{SPC} eventually get to the end of the menu and | |
2387 | then cycle around to the beginning. (The variable | |
2388 | @code{menu-prompt-more-char} specifies which character is used for | |
2389 | this; @key{SPC} is the default.) | |
2390 | ||
2391 | When the user has found the desired alternative from the menu, he or | |
2392 | she should type the corresponding character---the one whose binding is | |
2393 | that alternative. | |
2394 | ||
b8d4c8d0 GM |
2395 | @defvar menu-prompt-more-char |
2396 | This variable specifies the character to use to ask to see | |
2397 | the next line of a menu. Its initial value is 32, the code | |
2398 | for @key{SPC}. | |
2399 | @end defvar | |
2400 | ||
2401 | @node Menu Example | |
2402 | @subsection Menu Example | |
2403 | @cindex menu definition example | |
2404 | ||
2405 | Here is a complete example of defining a menu keymap. It is the | |
2406 | definition of the @samp{Replace} submenu in the @samp{Edit} menu in | |
2407 | the menu bar, and it uses the extended menu item format | |
2408 | (@pxref{Extended Menu Items}). First we create the keymap, and give | |
2409 | it a name: | |
2410 | ||
2411 | @smallexample | |
2412 | (defvar menu-bar-replace-menu (make-sparse-keymap "Replace")) | |
2413 | @end smallexample | |
2414 | ||
2415 | @noindent | |
2416 | Next we define the menu items: | |
2417 | ||
2418 | @smallexample | |
2419 | (define-key menu-bar-replace-menu [tags-repl-continue] | |
2420 | '(menu-item "Continue Replace" tags-loop-continue | |
d24880de | 2421 | :help "Continue last tags replace operation")) |
b8d4c8d0 GM |
2422 | (define-key menu-bar-replace-menu [tags-repl] |
2423 | '(menu-item "Replace in tagged files" tags-query-replace | |
d24880de | 2424 | :help "Interactively replace a regexp in all tagged files")) |
b8d4c8d0 GM |
2425 | (define-key menu-bar-replace-menu [separator-replace-tags] |
2426 | '(menu-item "--")) | |
2427 | ;; @r{@dots{}} | |
2428 | @end smallexample | |
2429 | ||
2430 | @noindent | |
2431 | Note the symbols which the bindings are ``made for''; these appear | |
2432 | inside square brackets, in the key sequence being defined. In some | |
2433 | cases, this symbol is the same as the command name; sometimes it is | |
16152b76 | 2434 | different. These symbols are treated as ``function keys'', but they are |
b8d4c8d0 GM |
2435 | not real function keys on the keyboard. They do not affect the |
2436 | functioning of the menu itself, but they are ``echoed'' in the echo area | |
2437 | when the user selects from the menu, and they appear in the output of | |
2438 | @code{where-is} and @code{apropos}. | |
2439 | ||
2440 | The menu in this example is intended for use with the mouse. If a | |
2441 | menu is intended for use with the keyboard, that is, if it is bound to | |
2442 | a key sequence ending with a keyboard event, then the menu items | |
2443 | should be bound to characters or ``real'' function keys, that can be | |
2444 | typed with the keyboard. | |
2445 | ||
2446 | The binding whose definition is @code{("--")} is a separator line. | |
2447 | Like a real menu item, the separator has a key symbol, in this case | |
2448 | @code{separator-replace-tags}. If one menu has two separators, they | |
2449 | must have two different key symbols. | |
2450 | ||
2451 | Here is how we make this menu appear as an item in the parent menu: | |
2452 | ||
2453 | @example | |
2454 | (define-key menu-bar-edit-menu [replace] | |
2455 | (list 'menu-item "Replace" menu-bar-replace-menu)) | |
2456 | @end example | |
2457 | ||
2458 | @noindent | |
2459 | Note that this incorporates the submenu keymap, which is the value of | |
2460 | the variable @code{menu-bar-replace-menu}, rather than the symbol | |
2461 | @code{menu-bar-replace-menu} itself. Using that symbol in the parent | |
2462 | menu item would be meaningless because @code{menu-bar-replace-menu} is | |
2463 | not a command. | |
2464 | ||
2465 | If you wanted to attach the same replace menu to a mouse click, you | |
2466 | can do it this way: | |
2467 | ||
2468 | @example | |
2469 | (define-key global-map [C-S-down-mouse-1] | |
2470 | menu-bar-replace-menu) | |
2471 | @end example | |
2472 | ||
2473 | @node Menu Bar | |
2474 | @subsection The Menu Bar | |
2475 | @cindex menu bar | |
2476 | ||
3d8badf4 CY |
2477 | On graphical displays, there is usually a @dfn{menu bar} at the top |
2478 | of each frame. @xref{Menu Bars,,,emacs, The GNU Emacs Manual}. Menu | |
2479 | bar items are subcommands of the fake ``function key'' | |
2480 | @code{menu-bar}, as defined in the active keymaps. | |
b8d4c8d0 GM |
2481 | |
2482 | To add an item to the menu bar, invent a fake ``function key'' of your | |
2483 | own (let's call it @var{key}), and make a binding for the key sequence | |
2484 | @code{[menu-bar @var{key}]}. Most often, the binding is a menu keymap, | |
2485 | so that pressing a button on the menu bar item leads to another menu. | |
2486 | ||
3d8badf4 | 2487 | When more than one active keymap defines the same ``function key'' |
b8d4c8d0 GM |
2488 | for the menu bar, the item appears just once. If the user clicks on |
2489 | that menu bar item, it brings up a single, combined menu containing | |
2490 | all the subcommands of that item---the global subcommands, the local | |
2491 | subcommands, and the minor mode subcommands. | |
2492 | ||
2493 | The variable @code{overriding-local-map} is normally ignored when | |
2494 | determining the menu bar contents. That is, the menu bar is computed | |
2495 | from the keymaps that would be active if @code{overriding-local-map} | |
2496 | were @code{nil}. @xref{Active Keymaps}. | |
2497 | ||
b8d4c8d0 GM |
2498 | Here's an example of setting up a menu bar item: |
2499 | ||
2500 | @example | |
b8d4c8d0 GM |
2501 | @group |
2502 | ;; @r{Make a menu keymap (with a prompt string)} | |
2503 | ;; @r{and make it the menu bar item's definition.} | |
2504 | (define-key global-map [menu-bar words] | |
2505 | (cons "Words" (make-sparse-keymap "Words"))) | |
2506 | @end group | |
2507 | ||
2508 | @group | |
2509 | ;; @r{Define specific subcommands in this menu.} | |
2510 | (define-key global-map | |
2511 | [menu-bar words forward] | |
2512 | '("Forward word" . forward-word)) | |
2513 | @end group | |
2514 | @group | |
2515 | (define-key global-map | |
2516 | [menu-bar words backward] | |
2517 | '("Backward word" . backward-word)) | |
2518 | @end group | |
2519 | @end example | |
2520 | ||
2521 | A local keymap can cancel a menu bar item made by the global keymap by | |
2522 | rebinding the same fake function key with @code{undefined} as the | |
2523 | binding. For example, this is how Dired suppresses the @samp{Edit} menu | |
2524 | bar item: | |
2525 | ||
2526 | @example | |
2527 | (define-key dired-mode-map [menu-bar edit] 'undefined) | |
2528 | @end example | |
2529 | ||
2530 | @noindent | |
c7c32279 CY |
2531 | Here, @code{edit} is the fake function key used by the global map for |
2532 | the @samp{Edit} menu bar item. The main reason to suppress a global | |
b8d4c8d0 GM |
2533 | menu bar item is to regain space for mode-specific items. |
2534 | ||
2535 | @defvar menu-bar-final-items | |
2536 | Normally the menu bar shows global items followed by items defined by the | |
2537 | local maps. | |
2538 | ||
2539 | This variable holds a list of fake function keys for items to display at | |
2540 | the end of the menu bar rather than in normal sequence. The default | |
2541 | value is @code{(help-menu)}; thus, the @samp{Help} menu item normally appears | |
2542 | at the end of the menu bar, following local menu items. | |
2543 | @end defvar | |
2544 | ||
2545 | @defvar menu-bar-update-hook | |
2546 | This normal hook is run by redisplay to update the menu bar contents, | |
2547 | before redisplaying the menu bar. You can use it to update submenus | |
2548 | whose contents should vary. Since this hook is run frequently, we | |
2549 | advise you to ensure that the functions it calls do not take much time | |
2550 | in the usual case. | |
2551 | @end defvar | |
2552 | ||
c7c32279 CY |
2553 | Next to every menu bar item, Emacs displays a key binding that runs |
2554 | the same command (if such a key binding exists). This serves as a | |
2555 | convenient hint for users who do not know the key binding. If a | |
2556 | command has multiple bindings, Emacs normally displays the first one | |
2557 | it finds. You can specify one particular key binding by assigning an | |
21ffa320 CY |
2558 | @code{:advertised-binding} symbol property to the command. @xref{Keys |
2559 | in Documentation}. | |
c7c32279 | 2560 | |
b8d4c8d0 GM |
2561 | @node Tool Bar |
2562 | @subsection Tool bars | |
2563 | @cindex tool bar | |
2564 | ||
3d8badf4 CY |
2565 | A @dfn{tool bar} is a row of clickable icons at the top of a frame, |
2566 | just below the menu bar. @xref{Tool Bars,,,emacs, The GNU Emacs | |
2567 | Manual}. | |
b8d4c8d0 | 2568 | |
3d8badf4 CY |
2569 | On each frame, the frame parameter @code{tool-bar-lines} controls |
2570 | how many lines' worth of height to reserve for the tool bar. A zero | |
2571 | value suppresses the tool bar. If the value is nonzero, and | |
2572 | @code{auto-resize-tool-bars} is non-@code{nil}, the tool bar expands | |
2573 | and contracts automatically as needed to hold the specified contents. | |
2574 | If the value is @code{grow-only}, the tool bar expands automatically, | |
2575 | but does not contract automatically. | |
b8d4c8d0 GM |
2576 | |
2577 | The tool bar contents are controlled by a menu keymap attached to a | |
2578 | fake ``function key'' called @code{tool-bar} (much like the way the menu | |
2579 | bar is controlled). So you define a tool bar item using | |
2580 | @code{define-key}, like this: | |
2581 | ||
2582 | @example | |
2583 | (define-key global-map [tool-bar @var{key}] @var{item}) | |
2584 | @end example | |
2585 | ||
2586 | @noindent | |
2587 | where @var{key} is a fake ``function key'' to distinguish this item from | |
2588 | other items, and @var{item} is a menu item key binding (@pxref{Extended | |
2589 | Menu Items}), which says how to display this item and how it behaves. | |
2590 | ||
2591 | The usual menu keymap item properties, @code{:visible}, | |
2592 | @code{:enable}, @code{:button}, and @code{:filter}, are useful in | |
2593 | tool bar bindings and have their normal meanings. The @var{real-binding} | |
2594 | in the item must be a command, not a keymap; in other words, it does not | |
2595 | work to define a tool bar icon as a prefix key. | |
2596 | ||
2597 | The @code{:help} property specifies a ``help-echo'' string to display | |
2598 | while the mouse is on that item. This is displayed in the same way as | |
2599 | @code{help-echo} text properties (@pxref{Help display}). | |
2600 | ||
2601 | In addition, you should use the @code{:image} property; | |
2602 | this is how you specify the image to display in the tool bar: | |
2603 | ||
2604 | @table @code | |
2605 | @item :image @var{image} | |
2606 | @var{images} is either a single image specification or a vector of four | |
2607 | image specifications. If you use a vector of four, | |
2608 | one of them is used, depending on circumstances: | |
2609 | ||
2610 | @table @asis | |
2611 | @item item 0 | |
2612 | Used when the item is enabled and selected. | |
2613 | @item item 1 | |
2614 | Used when the item is enabled and deselected. | |
2615 | @item item 2 | |
2616 | Used when the item is disabled and selected. | |
2617 | @item item 3 | |
2618 | Used when the item is disabled and deselected. | |
2619 | @end table | |
2620 | @end table | |
2621 | ||
2622 | If @var{image} is a single image specification, Emacs draws the tool bar | |
2623 | button in disabled state by applying an edge-detection algorithm to the | |
2624 | image. | |
2625 | ||
eafa12e6 | 2626 | The @code{:rtl} property specifies an alternative image to use for |
3d8badf4 | 2627 | right-to-left languages. Only the GTK+ version of Emacs supports this |
eafa12e6 JD |
2628 | at present. |
2629 | ||
f7c9199f GM |
2630 | Like the menu bar, the tool bar can display separators (@pxref{Menu |
2631 | Separators}). Tool bar separators are vertical rather than | |
3d8badf4 CY |
2632 | horizontal, though, and only a single style is supported. They are |
2633 | represented in the tool bar keymap by @code{(menu-item "--")} entries; | |
2634 | properties like @code{:visible} are not supported for tool bar | |
2635 | separators. Separators are rendered natively in GTK+ and Nextstep | |
2636 | tool bars; in the other cases, they are rendered using an image of a | |
2637 | vertical line. | |
f7c9199f | 2638 | |
b8d4c8d0 GM |
2639 | The default tool bar is defined so that items specific to editing do not |
2640 | appear for major modes whose command symbol has a @code{mode-class} | |
2641 | property of @code{special} (@pxref{Major Mode Conventions}). Major | |
2642 | modes may add items to the global bar by binding @code{[tool-bar | |
2643 | @var{foo}]} in their local map. It makes sense for some major modes to | |
2644 | replace the default tool bar items completely, since not many can be | |
2645 | accommodated conveniently, and the default bindings make this easy by | |
2646 | using an indirection through @code{tool-bar-map}. | |
2647 | ||
2648 | @defvar tool-bar-map | |
2649 | By default, the global map binds @code{[tool-bar]} as follows: | |
3d8badf4 | 2650 | |
b8d4c8d0 GM |
2651 | @example |
2652 | (global-set-key [tool-bar] | |
3d8badf4 CY |
2653 | `(menu-item ,(purecopy "tool bar") ignore |
2654 | :filter tool-bar-make-keymap)) | |
b8d4c8d0 | 2655 | @end example |
3d8badf4 | 2656 | |
b8d4c8d0 | 2657 | @noindent |
3d8badf4 CY |
2658 | The function @code{tool-bar-make-keymap}, in turn, derives the actual |
2659 | tool bar map dynamically from the value of the variable | |
2660 | @code{tool-bar-map}. Hence, you should normally adjust the default | |
2661 | (global) tool bar by changing that map. Some major modes, such as | |
2662 | Info mode, completely replace the global tool bar by making | |
2663 | @code{tool-bar-map} buffer-local and setting it to a different keymap. | |
b8d4c8d0 GM |
2664 | @end defvar |
2665 | ||
2666 | There are two convenience functions for defining tool bar items, as | |
2667 | follows. | |
2668 | ||
2669 | @defun tool-bar-add-item icon def key &rest props | |
2670 | This function adds an item to the tool bar by modifying | |
2671 | @code{tool-bar-map}. The image to use is defined by @var{icon}, which | |
2672 | is the base name of an XPM, XBM or PBM image file to be located by | |
2673 | @code{find-image}. Given a value @samp{"exit"}, say, @file{exit.xpm}, | |
2674 | @file{exit.pbm} and @file{exit.xbm} would be searched for in that order | |
2675 | on a color display. On a monochrome display, the search order is | |
2676 | @samp{.pbm}, @samp{.xbm} and @samp{.xpm}. The binding to use is the | |
2677 | command @var{def}, and @var{key} is the fake function key symbol in the | |
2678 | prefix keymap. The remaining arguments @var{props} are additional | |
2679 | property list elements to add to the menu item specification. | |
2680 | ||
2681 | To define items in some local map, bind @code{tool-bar-map} with | |
2682 | @code{let} around calls of this function: | |
2683 | @example | |
2684 | (defvar foo-tool-bar-map | |
2685 | (let ((tool-bar-map (make-sparse-keymap))) | |
2686 | (tool-bar-add-item @dots{}) | |
2687 | @dots{} | |
2688 | tool-bar-map)) | |
2689 | @end example | |
2690 | @end defun | |
2691 | ||
2692 | @defun tool-bar-add-item-from-menu command icon &optional map &rest props | |
2693 | This function is a convenience for defining tool bar items which are | |
2694 | consistent with existing menu bar bindings. The binding of | |
2695 | @var{command} is looked up in the menu bar in @var{map} (default | |
2696 | @code{global-map}) and modified to add an image specification for | |
2697 | @var{icon}, which is found in the same way as by | |
2698 | @code{tool-bar-add-item}. The resulting binding is then placed in | |
2699 | @code{tool-bar-map}, so use this function only for global tool bar | |
2700 | items. | |
2701 | ||
2702 | @var{map} must contain an appropriate keymap bound to | |
2703 | @code{[menu-bar]}. The remaining arguments @var{props} are additional | |
2704 | property list elements to add to the menu item specification. | |
2705 | @end defun | |
2706 | ||
2707 | @defun tool-bar-local-item-from-menu command icon in-map &optional from-map &rest props | |
2708 | This function is used for making non-global tool bar items. Use it | |
2709 | like @code{tool-bar-add-item-from-menu} except that @var{in-map} | |
2710 | specifies the local map to make the definition in. The argument | |
2711 | @var{from-map} is like the @var{map} argument of | |
2712 | @code{tool-bar-add-item-from-menu}. | |
2713 | @end defun | |
2714 | ||
9c283d5b | 2715 | @defvar auto-resize-tool-bars |
b8d4c8d0 GM |
2716 | If this variable is non-@code{nil}, the tool bar automatically resizes to |
2717 | show all defined tool bar items---but not larger than a quarter of the | |
2718 | frame's height. | |
2719 | ||
2720 | If the value is @code{grow-only}, the tool bar expands automatically, | |
2721 | but does not contract automatically. To contract the tool bar, the | |
2722 | user has to redraw the frame by entering @kbd{C-l}. | |
9c283d5b CY |
2723 | |
2724 | If Emacs is built with GTK or Nextstep, the tool bar can only show one | |
2725 | line, so this variable has no effect. | |
b8d4c8d0 GM |
2726 | @end defvar |
2727 | ||
2728 | @defvar auto-raise-tool-bar-buttons | |
2729 | If this variable is non-@code{nil}, tool bar items display | |
2730 | in raised form when the mouse moves over them. | |
2731 | @end defvar | |
2732 | ||
2733 | @defvar tool-bar-button-margin | |
2734 | This variable specifies an extra margin to add around tool bar items. | |
2735 | The value is an integer, a number of pixels. The default is 4. | |
2736 | @end defvar | |
2737 | ||
2738 | @defvar tool-bar-button-relief | |
2739 | This variable specifies the shadow width for tool bar items. | |
2740 | The value is an integer, a number of pixels. The default is 1. | |
2741 | @end defvar | |
2742 | ||
2743 | @defvar tool-bar-border | |
2744 | This variable specifies the height of the border drawn below the tool | |
2745 | bar area. An integer value specifies height as a number of pixels. | |
2746 | If the value is one of @code{internal-border-width} (the default) or | |
2747 | @code{border-width}, the tool bar border height corresponds to the | |
2748 | corresponding frame parameter. | |
2749 | @end defvar | |
2750 | ||
2751 | You can define a special meaning for clicking on a tool bar item with | |
2752 | the shift, control, meta, etc., modifiers. You do this by setting up | |
2753 | additional items that relate to the original item through the fake | |
2754 | function keys. Specifically, the additional items should use the | |
2755 | modified versions of the same fake function key used to name the | |
2756 | original item. | |
2757 | ||
2758 | Thus, if the original item was defined this way, | |
2759 | ||
2760 | @example | |
2761 | (define-key global-map [tool-bar shell] | |
2762 | '(menu-item "Shell" shell | |
2763 | :image (image :type xpm :file "shell.xpm"))) | |
2764 | @end example | |
2765 | ||
2766 | @noindent | |
2767 | then here is how you can define clicking on the same tool bar image with | |
2768 | the shift modifier: | |
2769 | ||
2770 | @example | |
2771 | (define-key global-map [tool-bar S-shell] 'some-command) | |
2772 | @end example | |
2773 | ||
2774 | @xref{Function Keys}, for more information about how to add modifiers to | |
2775 | function keys. | |
2776 | ||
2777 | @node Modifying Menus | |
2778 | @subsection Modifying Menus | |
2779 | ||
2780 | When you insert a new item in an existing menu, you probably want to | |
2781 | put it in a particular place among the menu's existing items. If you | |
2782 | use @code{define-key} to add the item, it normally goes at the front of | |
2783 | the menu. To put it elsewhere in the menu, use @code{define-key-after}: | |
2784 | ||
2785 | @defun define-key-after map key binding &optional after | |
2786 | Define a binding in @var{map} for @var{key}, with value @var{binding}, | |
2787 | just like @code{define-key}, but position the binding in @var{map} after | |
2788 | the binding for the event @var{after}. The argument @var{key} should be | |
2789 | of length one---a vector or string with just one element. But | |
2790 | @var{after} should be a single event type---a symbol or a character, not | |
2791 | a sequence. The new binding goes after the binding for @var{after}. If | |
2792 | @var{after} is @code{t} or is omitted, then the new binding goes last, at | |
2793 | the end of the keymap. However, new bindings are added before any | |
2794 | inherited keymap. | |
2795 | ||
2796 | Here is an example: | |
2797 | ||
2798 | @example | |
2799 | (define-key-after my-menu [drink] | |
2800 | '("Drink" . drink-command) 'eat) | |
2801 | @end example | |
2802 | ||
2803 | @noindent | |
2804 | makes a binding for the fake function key @key{DRINK} and puts it | |
2805 | right after the binding for @key{EAT}. | |
2806 | ||
2807 | Here is how to insert an item called @samp{Work} in the @samp{Signals} | |
2808 | menu of Shell mode, after the item @code{break}: | |
2809 | ||
2810 | @example | |
2811 | (define-key-after | |
2812 | (lookup-key shell-mode-map [menu-bar signals]) | |
2813 | [work] '("Work" . work-command) 'break) | |
2814 | @end example | |
2815 | @end defun |