Commit | Line | Data |
---|---|---|
73804d4b RS |
1 | @c -*-texinfo-*- |
2 | @c This is part of the GNU Emacs Lisp Reference Manual. | |
f9f59935 | 3 | @c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1998 Free Software Foundation, Inc. |
73804d4b RS |
4 | @c See the file elisp.texi for copying conditions. |
5 | @setfilename ../info/keymaps | |
6 | @node Keymaps, Modes, Command Loop, Top | |
7 | @chapter Keymaps | |
8 | @cindex keymap | |
9 | ||
10 | The bindings between input events and commands are recorded in data | |
11 | structures called @dfn{keymaps}. Each binding in a keymap associates | |
f9f59935 RS |
12 | (or @dfn{binds}) an individual event type either to another keymap or to |
13 | a command. When an event type is bound to a keymap, that keymap is used | |
14 | to look up the next input event; this continues until a command is | |
15 | found. The whole process is called @dfn{key lookup}. | |
73804d4b RS |
16 | |
17 | @menu | |
18 | * Keymap Terminology:: Definitions of terms pertaining to keymaps. | |
19 | * Format of Keymaps:: What a keymap looks like as a Lisp object. | |
20 | * Creating Keymaps:: Functions to create and copy keymaps. | |
21 | * Inheritance and Keymaps:: How one keymap can inherit the bindings | |
22 | of another keymap. | |
23 | * Prefix Keys:: Defining a key with a keymap as its definition. | |
73804d4b RS |
24 | * Active Keymaps:: Each buffer has a local keymap |
25 | to override the standard (global) bindings. | |
26 | A minor mode can also override them. | |
27 | * Key Lookup:: How extracting elements from keymaps works. | |
28 | * Functions for Key Lookup:: How to request key lookup. | |
29 | * Changing Key Bindings:: Redefining a key in a keymap. | |
30 | * Key Binding Commands:: Interactive interfaces for redefining keys. | |
31 | * Scanning Keymaps:: Looking through all keymaps, for printing help. | |
f9f59935 | 32 | * Menu Keymaps:: Defining a menu as a keymap. |
73804d4b RS |
33 | @end menu |
34 | ||
35 | @node Keymap Terminology | |
36 | @section Keymap Terminology | |
37 | @cindex key | |
38 | @cindex keystroke | |
39 | @cindex key binding | |
40 | @cindex binding of a key | |
41 | @cindex complete key | |
42 | @cindex undefined key | |
43 | ||
44 | A @dfn{keymap} is a table mapping event types to definitions (which | |
45 | can be any Lisp objects, though only certain types are meaningful for | |
46 | execution by the command loop). Given an event (or an event type) and a | |
969fe9b5 RS |
47 | keymap, Emacs can get the event's definition. Events include |
48 | characters, function keys, and mouse actions (@pxref{Input Events}). | |
73804d4b RS |
49 | |
50 | A sequence of input events that form a unit is called a | |
51 | @dfn{key sequence}, or @dfn{key} for short. A sequence of one event | |
52 | is always a key sequence, and so are some multi-event sequences. | |
53 | ||
54 | A keymap determines a binding or definition for any key sequence. If | |
55 | the key sequence is a single event, its binding is the definition of the | |
56 | event in the keymap. The binding of a key sequence of more than one | |
57 | event is found by an iterative process: the binding of the first event | |
58 | is found, and must be a keymap; then the second event's binding is found | |
59 | in that keymap, and so on until all the events in the key sequence are | |
60 | used up. | |
61 | ||
62 | If the binding of a key sequence is a keymap, we call the key sequence | |
63 | a @dfn{prefix key}. Otherwise, we call it a @dfn{complete key} (because | |
87b2d5ff | 64 | no more events can be added to it). If the binding is @code{nil}, |
73804d4b RS |
65 | we call the key @dfn{undefined}. Examples of prefix keys are @kbd{C-c}, |
66 | @kbd{C-x}, and @kbd{C-x 4}. Examples of defined complete keys are | |
67 | @kbd{X}, @key{RET}, and @kbd{C-x 4 C-f}. Examples of undefined complete | |
68 | keys are @kbd{C-x C-g}, and @kbd{C-c 3}. @xref{Prefix Keys}, for more | |
69 | details. | |
70 | ||
71 | The rule for finding the binding of a key sequence assumes that the | |
72 | intermediate bindings (found for the events before the last) are all | |
73 | keymaps; if this is not so, the sequence of events does not form a | |
f9f59935 RS |
74 | unit---it is not really one key sequence. In other words, removing one |
75 | or more events from the end of any valid key sequence must always yield | |
76 | a prefix key. For example, @kbd{C-f C-n} is not a key sequence; | |
77 | @kbd{C-f} is not a prefix key, so a longer sequence starting with | |
78 | @kbd{C-f} cannot be a key sequence. | |
79 | ||
80 | The set of possible multi-event key sequences depends on the bindings | |
81 | for prefix keys; therefore, it can be different for different keymaps, | |
82 | and can change when bindings are changed. However, a one-event sequence | |
83 | is always a key sequence, because it does not depend on any prefix keys | |
84 | for its well-formedness. | |
73804d4b RS |
85 | |
86 | At any time, several primary keymaps are @dfn{active}---that is, in | |
87 | use for finding key bindings. These are the @dfn{global map}, which is | |
88 | shared by all buffers; the @dfn{local keymap}, which is usually | |
89 | associated with a specific major mode; and zero or more @dfn{minor mode | |
87b2d5ff | 90 | keymaps}, which belong to currently enabled minor modes. (Not all minor |
73804d4b RS |
91 | modes have keymaps.) The local keymap bindings shadow (i.e., take |
92 | precedence over) the corresponding global bindings. The minor mode | |
93 | keymaps shadow both local and global keymaps. @xref{Active Keymaps}, | |
94 | for details. | |
95 | ||
96 | @node Format of Keymaps | |
97 | @section Format of Keymaps | |
98 | @cindex format of keymaps | |
99 | @cindex keymap format | |
100 | @cindex full keymap | |
101 | @cindex sparse keymap | |
102 | ||
103 | A keymap is a list whose @sc{car} is the symbol @code{keymap}. The | |
104 | remaining elements of the list define the key bindings of the keymap. | |
105 | Use the function @code{keymapp} (see below) to test whether an object is | |
106 | a keymap. | |
107 | ||
f9f59935 RS |
108 | Several kinds of elements may appear in a keymap, after the symbol |
109 | @code{keymap} that begins it: | |
87b2d5ff | 110 | |
f9f59935 RS |
111 | @table @code |
112 | @item (@var{type} .@: @var{binding}) | |
113 | This specifies one binding, for events of type @var{type}. Each | |
114 | ordinary binding applies to events of a particular @dfn{event type}, | |
115 | which is always a character or a symbol. @xref{Classifying Events}. | |
73804d4b | 116 | |
f9f59935 | 117 | @item (t .@: @var{binding}) |
73804d4b | 118 | @cindex default key binding |
f9f59935 RS |
119 | This specifies a @dfn{default key binding}; any event not bound by other |
120 | elements of the keymap is given @var{binding} as its binding. Default | |
121 | bindings allow a keymap to bind all possible event types without having | |
122 | to enumerate all of them. A keymap that has a default binding | |
123 | completely masks any lower-precedence keymap. | |
124 | ||
125 | @item @var{vector} | |
126 | If an element of a keymap is a vector, the vector counts as bindings for | |
969fe9b5 RS |
127 | all the @sc{ASCII} characters, codes 0 through 127; vector element |
128 | @var{n} is the binding for the character with code @var{n}. This is a | |
129 | compact way to record lots of bindings. A keymap with such a vector is | |
130 | called a @dfn{full keymap}. Other keymaps are called @dfn{sparse | |
131 | keymaps}. | |
f9f59935 RS |
132 | |
133 | When a keymap contains a vector, it always defines a binding for each | |
134 | @sc{ASCII} character, even if the vector contains @code{nil} for that | |
969fe9b5 | 135 | character. Such a binding of @code{nil} overrides any default key |
a9f0a989 RS |
136 | binding in the keymap, for @sc{ASCII} characters. However, default |
137 | bindings are still meaningful for events other than @sc{ASCII} | |
138 | characters. A binding of @code{nil} does @emph{not} override | |
139 | lower-precedence keymaps; thus, if the local map gives a binding of | |
140 | @code{nil}, Emacs uses the binding from the global map. | |
73804d4b | 141 | |
f9f59935 | 142 | @item @var{string} |
73804d4b RS |
143 | @cindex keymap prompt string |
144 | @cindex overall prompt string | |
145 | @cindex prompt string of keymap | |
f9f59935 | 146 | Aside from bindings, a keymap can also have a string as an element. |
73804d4b RS |
147 | This is called the @dfn{overall prompt string} and makes it possible to |
148 | use the keymap as a menu. @xref{Menu Keymaps}. | |
f9f59935 | 149 | @end table |
73804d4b RS |
150 | |
151 | @cindex meta characters lookup | |
f9f59935 RS |
152 | Keymaps do not directly record bindings for the meta characters. |
153 | Instead, meta characters are regarded for | |
73804d4b RS |
154 | purposes of key lookup as sequences of two characters, the first of |
155 | which is @key{ESC} (or whatever is currently the value of | |
156 | @code{meta-prefix-char}). Thus, the key @kbd{M-a} is really represented | |
157 | as @kbd{@key{ESC} a}, and its global binding is found at the slot for | |
158 | @kbd{a} in @code{esc-map} (@pxref{Prefix Keys}). | |
159 | ||
160 | Here as an example is the local keymap for Lisp mode, a sparse | |
161 | keymap. It defines bindings for @key{DEL} and @key{TAB}, plus @kbd{C-c | |
162 | C-l}, @kbd{M-C-q}, and @kbd{M-C-x}. | |
163 | ||
164 | @example | |
165 | @group | |
166 | lisp-mode-map | |
167 | @result{} | |
168 | @end group | |
169 | @group | |
170 | (keymap | |
171 | ;; @key{TAB} | |
172 | (9 . lisp-indent-line) | |
173 | @end group | |
174 | @group | |
175 | ;; @key{DEL} | |
176 | (127 . backward-delete-char-untabify) | |
177 | @end group | |
178 | @group | |
179 | (3 keymap | |
180 | ;; @kbd{C-c C-l} | |
181 | (12 . run-lisp)) | |
182 | @end group | |
183 | @group | |
184 | (27 keymap | |
185 | ;; @r{@kbd{M-C-q}, treated as @kbd{@key{ESC} C-q}} | |
186 | (17 . indent-sexp) | |
187 | ;; @r{@kbd{M-C-x}, treated as @kbd{@key{ESC} C-x}} | |
188 | (24 . lisp-send-defun))) | |
189 | @end group | |
190 | @end example | |
191 | ||
192 | @defun keymapp object | |
193 | This function returns @code{t} if @var{object} is a keymap, @code{nil} | |
87b2d5ff | 194 | otherwise. More precisely, this function tests for a list whose |
73804d4b RS |
195 | @sc{car} is @code{keymap}. |
196 | ||
197 | @example | |
198 | @group | |
199 | (keymapp '(keymap)) | |
200 | @result{} t | |
201 | @end group | |
202 | @group | |
203 | (keymapp (current-global-map)) | |
204 | @result{} t | |
205 | @end group | |
206 | @end example | |
207 | @end defun | |
208 | ||
209 | @node Creating Keymaps | |
210 | @section Creating Keymaps | |
211 | @cindex creating keymaps | |
212 | ||
213 | Here we describe the functions for creating keymaps. | |
214 | ||
f9f59935 | 215 | @c ??? This should come after make-sparse-keymap |
73804d4b | 216 | @defun make-keymap &optional prompt |
87b2d5ff RS |
217 | This function creates and returns a new full keymap (i.e., one |
218 | containing a vector of length 128 for defining all the @sc{ASCII} | |
73804d4b RS |
219 | characters). The new keymap initially binds all @sc{ASCII} characters |
220 | to @code{nil}, and does not bind any other kind of event. | |
221 | ||
222 | @example | |
223 | @group | |
224 | (make-keymap) | |
225 | @result{} (keymap [nil nil nil @dots{} nil nil]) | |
226 | @end group | |
227 | @end example | |
228 | ||
229 | If you specify @var{prompt}, that becomes the overall prompt string for | |
230 | the keymap. The prompt string is useful for menu keymaps (@pxref{Menu | |
231 | Keymaps}). | |
232 | @end defun | |
233 | ||
234 | @defun make-sparse-keymap &optional prompt | |
235 | This function creates and returns a new sparse keymap with no entries. | |
236 | The new keymap does not bind any events. The argument @var{prompt} | |
237 | specifies a prompt string, as in @code{make-keymap}. | |
238 | ||
239 | @example | |
240 | @group | |
241 | (make-sparse-keymap) | |
242 | @result{} (keymap) | |
243 | @end group | |
244 | @end example | |
245 | @end defun | |
246 | ||
247 | @defun copy-keymap keymap | |
87b2d5ff | 248 | This function returns a copy of @var{keymap}. Any keymaps that |
73804d4b RS |
249 | appear directly as bindings in @var{keymap} are also copied recursively, |
250 | and so on to any number of levels. However, recursive copying does not | |
251 | take place when the definition of a character is a symbol whose function | |
252 | definition is a keymap; the same symbol appears in the new copy. | |
253 | @c Emacs 19 feature | |
254 | ||
255 | @example | |
256 | @group | |
257 | (setq map (copy-keymap (current-local-map))) | |
258 | @result{} (keymap | |
259 | @end group | |
260 | @group | |
261 | ;; @r{(This implements meta characters.)} | |
262 | (27 keymap | |
263 | (83 . center-paragraph) | |
264 | (115 . center-line)) | |
265 | (9 . tab-to-tab-stop)) | |
266 | @end group | |
267 | ||
268 | @group | |
269 | (eq map (current-local-map)) | |
270 | @result{} nil | |
271 | @end group | |
272 | @group | |
273 | (equal map (current-local-map)) | |
274 | @result{} t | |
275 | @end group | |
276 | @end example | |
277 | @end defun | |
278 | ||
279 | @node Inheritance and Keymaps | |
280 | @section Inheritance and Keymaps | |
281 | @cindex keymap inheritance | |
282 | @cindex inheriting a keymap's bindings | |
283 | ||
0521d6f5 RS |
284 | A keymap can inherit the bindings of another keymap, which we call the |
285 | @dfn{parent keymap}. Such a keymap looks like this: | |
73804d4b RS |
286 | |
287 | @example | |
0521d6f5 | 288 | (keymap @var{bindings}@dots{} . @var{parent-keymap}) |
73804d4b RS |
289 | @end example |
290 | ||
291 | @noindent | |
292 | The effect is that this keymap inherits all the bindings of | |
0521d6f5 | 293 | @var{parent-keymap}, whatever they may be at the time a key is looked up, |
73804d4b RS |
294 | but can add to them or override them with @var{bindings}. |
295 | ||
0521d6f5 | 296 | If you change the bindings in @var{parent-keymap} using @code{define-key} |
73804d4b RS |
297 | or other key-binding functions, these changes are visible in the |
298 | inheriting keymap unless shadowed by @var{bindings}. The converse is | |
299 | not true: if you use @code{define-key} to change the inheriting keymap, | |
0521d6f5 RS |
300 | that affects @var{bindings}, but has no effect on @var{parent-keymap}. |
301 | ||
302 | The proper way to construct a keymap with a parent is to use | |
303 | @code{set-keymap-parent}; if you have code that directly constructs a | |
304 | keymap with a parent, please convert the program to use | |
305 | @code{set-keymap-parent} instead. | |
306 | ||
307 | @defun keymap-parent keymap | |
308 | This returns the parent keymap of @var{keymap}. If @var{keymap} | |
309 | has no parent, @code{keymap-parent} returns @code{nil}. | |
310 | @end defun | |
311 | ||
312 | @defun set-keymap-parent keymap parent | |
313 | This sets the parent keymap of @var{keymap} to @var{parent}, and returns | |
314 | @var{parent}. If @var{parent} is @code{nil}, this function gives | |
315 | @var{keymap} no parent at all. | |
316 | ||
317 | If @var{keymap} has submaps (bindings for prefix keys), they too receive | |
318 | new parent keymaps that reflect what @var{parent} specifies for those | |
319 | prefix keys. | |
320 | @end defun | |
73804d4b RS |
321 | |
322 | Here is an example showing how to make a keymap that inherits | |
323 | from @code{text-mode-map}: | |
324 | ||
325 | @example | |
0521d6f5 RS |
326 | (let ((map (make-sparse-keymap))) |
327 | (set-keymap-parent map text-mode-map) | |
328 | map) | |
73804d4b RS |
329 | @end example |
330 | ||
331 | @node Prefix Keys | |
332 | @section Prefix Keys | |
333 | @cindex prefix key | |
334 | ||
f9f59935 | 335 | A @dfn{prefix key} is a key sequence whose binding is a keymap. The |
969fe9b5 | 336 | keymap defines what to do with key sequences that extend the prefix key. |
f9f59935 RS |
337 | For example, @kbd{C-x} is a prefix key, and it uses a keymap that is |
338 | also stored in the variable @code{ctl-x-map}. This keymap defines | |
339 | bindings for key sequences starting with @kbd{C-x}. | |
340 | ||
1911e6e5 RS |
341 | Some of the standard Emacs prefix keys use keymaps that are |
342 | also found in Lisp variables: | |
73804d4b RS |
343 | |
344 | @itemize @bullet | |
345 | @item | |
346 | @vindex esc-map | |
347 | @findex ESC-prefix | |
f9f59935 RS |
348 | @code{esc-map} is the global keymap for the @key{ESC} prefix key. Thus, |
349 | the global definitions of all meta characters are actually found here. | |
350 | This map is also the function definition of @code{ESC-prefix}. | |
73804d4b RS |
351 | |
352 | @item | |
353 | @cindex @kbd{C-h} | |
a9f0a989 | 354 | @code{help-map} is the global keymap for the @kbd{C-h} prefix key. |
73804d4b RS |
355 | |
356 | @item | |
357 | @cindex @kbd{C-c} | |
358 | @vindex mode-specific-map | |
f9f59935 RS |
359 | @code{mode-specific-map} is the global keymap for the prefix key |
360 | @kbd{C-c}. This map is actually global, not mode-specific, but its name | |
361 | provides useful information about @kbd{C-c} in the output of @kbd{C-h b} | |
362 | (@code{display-bindings}), since the main use of this prefix key is for | |
363 | mode-specific bindings. | |
73804d4b RS |
364 | |
365 | @item | |
366 | @cindex @kbd{C-x} | |
367 | @vindex ctl-x-map | |
368 | @findex Control-X-prefix | |
a9f0a989 RS |
369 | @code{ctl-x-map} is the global keymap used for the @kbd{C-x} prefix key. |
370 | This map is found via the function cell of the symbol | |
f9f59935 | 371 | @code{Control-X-prefix}. |
73804d4b | 372 | |
1911e6e5 RS |
373 | @item |
374 | @cindex @kbd{C-x @key{RET}} | |
375 | @vindex mule-keymap | |
376 | @code{mule-keymap} is the global keymap used for the @kbd{C-x @key{RET}} | |
377 | prefix key. | |
378 | ||
73804d4b RS |
379 | @item |
380 | @cindex @kbd{C-x 4} | |
381 | @vindex ctl-x-4-map | |
f9f59935 RS |
382 | @code{ctl-x-4-map} is the global keymap used for the @kbd{C-x 4} prefix |
383 | key. | |
73804d4b RS |
384 | |
385 | @c Emacs 19 feature | |
386 | @item | |
387 | @cindex @kbd{C-x 5} | |
388 | @vindex ctl-x-5-map | |
f9f59935 RS |
389 | @code{ctl-x-5-map} is the global keymap used for the @kbd{C-x 5} prefix |
390 | key. | |
73804d4b RS |
391 | |
392 | @c Emacs 19 feature | |
393 | @item | |
1911e6e5 RS |
394 | @cindex @kbd{C-x 6} |
395 | @vindex 2C-mode-map | |
396 | @code{2C-mode-map} is the global keymap used for the @kbd{C-x 6} prefix | |
397 | key. | |
398 | ||
399 | @item | |
400 | @cindex @kbd{C-x v} | |
401 | @vindex vc-prefix-map | |
402 | @code{vc-prefix-map} is the global keymap used for the @kbd{C-x v} prefix | |
403 | key. | |
404 | ||
405 | @item | |
406 | @cindex @kbd{M-g} | |
407 | @vindex facemenu-keymap | |
408 | @code{facemenu-keymap} is the global keymap used for the @kbd{M-g} | |
409 | prefix key. | |
410 | ||
411 | @c Emacs 19 feature | |
412 | @item | |
413 | The other Emacs prefix keys are @kbd{C-x @@}, @kbd{C-x a i}, @kbd{C-x | |
414 | @key{ESC}} and @kbd{@key{ESC} @key{ESC}}. They use keymaps that have no | |
415 | special names. | |
73804d4b RS |
416 | @end itemize |
417 | ||
f9f59935 RS |
418 | The keymap binding of a prefix key is used for looking up the event |
419 | that follows the prefix key. (It may instead be a symbol whose function | |
420 | definition is a keymap. The effect is the same, but the symbol serves | |
421 | as a name for the prefix key.) Thus, the binding of @kbd{C-x} is the | |
a9f0a989 | 422 | symbol @code{Control-X-prefix}, whose function cell holds the keymap |
f9f59935 | 423 | for @kbd{C-x} commands. (The same keymap is also the value of |
73804d4b RS |
424 | @code{ctl-x-map}.) |
425 | ||
87b2d5ff RS |
426 | Prefix key definitions can appear in any active keymap. The |
427 | definitions of @kbd{C-c}, @kbd{C-x}, @kbd{C-h} and @key{ESC} as prefix | |
428 | keys appear in the global map, so these prefix keys are always | |
73804d4b RS |
429 | available. Major and minor modes can redefine a key as a prefix by |
430 | putting a prefix key definition for it in the local map or the minor | |
431 | mode's map. @xref{Active Keymaps}. | |
432 | ||
433 | If a key is defined as a prefix in more than one active map, then its | |
434 | various definitions are in effect merged: the commands defined in the | |
435 | minor mode keymaps come first, followed by those in the local map's | |
436 | prefix definition, and then by those from the global map. | |
437 | ||
438 | In the following example, we make @kbd{C-p} a prefix key in the local | |
439 | keymap, in such a way that @kbd{C-p} is identical to @kbd{C-x}. Then | |
440 | the binding for @kbd{C-p C-f} is the function @code{find-file}, just | |
441 | like @kbd{C-x C-f}. The key sequence @kbd{C-p 6} is not found in any | |
442 | active keymap. | |
443 | ||
444 | @example | |
445 | @group | |
446 | (use-local-map (make-sparse-keymap)) | |
447 | @result{} nil | |
448 | @end group | |
449 | @group | |
450 | (local-set-key "\C-p" ctl-x-map) | |
451 | @result{} nil | |
452 | @end group | |
453 | @group | |
454 | (key-binding "\C-p\C-f") | |
455 | @result{} find-file | |
456 | @end group | |
457 | ||
458 | @group | |
459 | (key-binding "\C-p6") | |
460 | @result{} nil | |
461 | @end group | |
462 | @end example | |
463 | ||
464 | @defun define-prefix-command symbol | |
465 | @cindex prefix command | |
f9f59935 RS |
466 | This function prepares @var{symbol} for use as a prefix key's binding: |
467 | it creates a full keymap and stores it as @var{symbol}'s function | |
468 | definition. Subsequently binding a key sequence to @var{symbol} will | |
469 | make that key sequence into a prefix key. | |
470 | ||
471 | This function also sets @var{symbol} as a variable, with the keymap as | |
472 | its value. It returns @var{symbol}. | |
473 | ||
474 | @c In Emacs version 18, only the function definition of @var{symbol} was | |
475 | @c set, not the value as a variable. | |
73804d4b RS |
476 | @end defun |
477 | ||
87b2d5ff RS |
478 | @node Active Keymaps |
479 | @section Active Keymaps | |
480 | @cindex active keymap | |
481 | @cindex global keymap | |
482 | @cindex local keymap | |
73804d4b | 483 | |
87b2d5ff RS |
484 | Emacs normally contains many keymaps; at any given time, just a few of |
485 | them are @dfn{active} in that they participate in the interpretation | |
486 | of user input. These are the global keymap, the current buffer's | |
487 | local keymap, and the keymaps of any enabled minor modes. | |
73804d4b | 488 | |
87b2d5ff RS |
489 | The @dfn{global keymap} holds the bindings of keys that are defined |
490 | regardless of the current buffer, such as @kbd{C-f}. The variable | |
491 | @code{global-map} holds this keymap, which is always active. | |
73804d4b | 492 | |
87b2d5ff RS |
493 | Each buffer may have another keymap, its @dfn{local keymap}, which may |
494 | contain new or overriding definitions for keys. The current buffer's | |
495 | local keymap is always active except when @code{overriding-local-map} | |
496 | overrides it. Text properties can specify an alternative local map for | |
497 | certain parts of the buffer; see @ref{Special Properties}. | |
73804d4b | 498 | |
a9f0a989 | 499 | Each minor mode can have a keymap; if it does, the keymap is active |
87b2d5ff | 500 | when the minor mode is enabled. |
73804d4b | 501 | |
87b2d5ff RS |
502 | The variable @code{overriding-local-map}, if non-@code{nil}, specifies |
503 | another local keymap that overrides the buffer's local map and all the | |
504 | minor mode keymaps. | |
73804d4b | 505 | |
87b2d5ff RS |
506 | All the active keymaps are used together to determine what command to |
507 | execute when a key is entered. Emacs searches these maps one by one, in | |
969fe9b5 RS |
508 | order of decreasing precedence, until it finds a binding in one of the |
509 | maps. The procedure for searching a single keymap is called @dfn{key | |
510 | lookup}; see @ref{Key Lookup}. | |
73804d4b | 511 | |
a9f0a989 RS |
512 | Normally, Emacs first searches for the key in the minor mode maps, in |
513 | the order specified by @code{minor-mode-map-alist}; if they do not | |
514 | supply a binding for the key, Emacs searches the local map; if that too | |
515 | has no binding, Emacs then searches the global map. However, if | |
516 | @code{overriding-local-map} is non-@code{nil}, Emacs searches that map | |
517 | first, before the global map. | |
73804d4b | 518 | |
87b2d5ff RS |
519 | @cindex major mode keymap |
520 | Since every buffer that uses the same major mode normally uses the | |
521 | same local keymap, you can think of the keymap as local to the mode. A | |
522 | change to the local keymap of a buffer (using @code{local-set-key}, for | |
523 | example) is seen also in the other buffers that share that keymap. | |
73804d4b | 524 | |
969fe9b5 RS |
525 | The local keymaps that are used for Lisp mode and some other major |
526 | modes exist even if they have not yet been used. These local maps are | |
527 | the values of variables such as @code{lisp-mode-map}. For most major | |
528 | modes, which are less frequently used, the local keymap is constructed | |
529 | only when the mode is used for the first time in a session. | |
73804d4b | 530 | |
87b2d5ff RS |
531 | The minibuffer has local keymaps, too; they contain various completion |
532 | and exit commands. @xref{Intro to Minibuffers}. | |
73804d4b | 533 | |
a9f0a989 RS |
534 | Emacs has other keymaps that are used in a different way---translating |
535 | events within @code{read-key-sequence}. @xref{Translating Input}. | |
536 | ||
87b2d5ff | 537 | @xref{Standard Keymaps}, for a list of standard keymaps. |
73804d4b | 538 | |
87b2d5ff RS |
539 | @defvar global-map |
540 | This variable contains the default global keymap that maps Emacs | |
541 | keyboard input to commands. The global keymap is normally this keymap. | |
542 | The default global keymap is a full keymap that binds | |
543 | @code{self-insert-command} to all of the printing characters. | |
73804d4b | 544 | |
87b2d5ff RS |
545 | It is normal practice to change the bindings in the global map, but you |
546 | should not assign this variable any value other than the keymap it starts | |
547 | out with. | |
548 | @end defvar | |
73804d4b | 549 | |
87b2d5ff RS |
550 | @defun current-global-map |
551 | This function returns the current global keymap. This is the | |
552 | same as the value of @code{global-map} unless you change one or the | |
553 | other. | |
73804d4b | 554 | |
73804d4b | 555 | @example |
87b2d5ff RS |
556 | @group |
557 | (current-global-map) | |
558 | @result{} (keymap [set-mark-command beginning-of-line @dots{} | |
559 | delete-backward-char]) | |
560 | @end group | |
73804d4b | 561 | @end example |
87b2d5ff | 562 | @end defun |
73804d4b | 563 | |
87b2d5ff RS |
564 | @defun current-local-map |
565 | This function returns the current buffer's local keymap, or @code{nil} | |
566 | if it has none. In the following example, the keymap for the | |
567 | @samp{*scratch*} buffer (using Lisp Interaction mode) is a sparse keymap | |
568 | in which the entry for @key{ESC}, @sc{ASCII} code 27, is another sparse | |
569 | keymap. | |
73804d4b | 570 | |
87b2d5ff RS |
571 | @example |
572 | @group | |
573 | (current-local-map) | |
574 | @result{} (keymap | |
575 | (10 . eval-print-last-sexp) | |
576 | (9 . lisp-indent-line) | |
577 | (127 . backward-delete-char-untabify) | |
578 | @end group | |
579 | @group | |
580 | (27 keymap | |
581 | (24 . eval-defun) | |
582 | (17 . indent-sexp))) | |
583 | @end group | |
584 | @end example | |
585 | @end defun | |
73804d4b | 586 | |
87b2d5ff RS |
587 | @defun current-minor-mode-maps |
588 | This function returns a list of the keymaps of currently enabled minor modes. | |
589 | @end defun | |
73804d4b | 590 | |
87b2d5ff RS |
591 | @defun use-global-map keymap |
592 | This function makes @var{keymap} the new current global keymap. It | |
593 | returns @code{nil}. | |
73804d4b | 594 | |
87b2d5ff RS |
595 | It is very unusual to change the global keymap. |
596 | @end defun | |
73804d4b | 597 | |
87b2d5ff RS |
598 | @defun use-local-map keymap |
599 | This function makes @var{keymap} the new local keymap of the current | |
600 | buffer. If @var{keymap} is @code{nil}, then the buffer has no local | |
601 | keymap. @code{use-local-map} returns @code{nil}. Most major mode | |
602 | commands use this function. | |
603 | @end defun | |
73804d4b | 604 | |
87b2d5ff RS |
605 | @c Emacs 19 feature |
606 | @defvar minor-mode-map-alist | |
607 | This variable is an alist describing keymaps that may or may not be | |
608 | active according to the values of certain variables. Its elements look | |
609 | like this: | |
73804d4b | 610 | |
87b2d5ff RS |
611 | @example |
612 | (@var{variable} . @var{keymap}) | |
613 | @end example | |
73804d4b | 614 | |
87b2d5ff RS |
615 | The keymap @var{keymap} is active whenever @var{variable} has a |
616 | non-@code{nil} value. Typically @var{variable} is the variable that | |
617 | enables or disables a minor mode. @xref{Keymaps and Minor Modes}. | |
73804d4b | 618 | |
87b2d5ff RS |
619 | Note that elements of @code{minor-mode-map-alist} do not have the same |
620 | structure as elements of @code{minor-mode-alist}. The map must be the | |
f9f59935 | 621 | @sc{cdr} of the element; a list with the map as the @sc{cadr} will not |
969fe9b5 RS |
622 | do. The @sc{cadr} can be either a keymap (a list) or a symbol |
623 | whose function definition is a keymap. | |
73804d4b | 624 | |
87b2d5ff RS |
625 | When more than one minor mode keymap is active, their order of priority |
626 | is the order of @code{minor-mode-map-alist}. But you should design | |
627 | minor modes so that they don't interfere with each other. If you do | |
628 | this properly, the order will not matter. | |
73804d4b | 629 | |
f9f59935 RS |
630 | See @ref{Keymaps and Minor Modes}, for more information about minor |
631 | modes. See also @code{minor-mode-key-binding} (@pxref{Functions for Key | |
632 | Lookup}). | |
633 | @end defvar | |
634 | ||
f9f59935 | 635 | @defvar minor-mode-overriding-map-alist |
a9f0a989 | 636 | @tindex minor-mode-overriding-map-alist |
f9f59935 RS |
637 | This variable allows major modes to override the key bindings for |
638 | particular minor modes. The elements of this alist look like the | |
639 | elements of @code{minor-mode-map-alist}: @code{(@var{variable} | |
a9f0a989 RS |
640 | . @var{keymap})}. |
641 | ||
1911e6e5 | 642 | If a variable appears as an element of |
a9f0a989 RS |
643 | @code{minor-mode-overriding-map-alist}, the map specified by that |
644 | element totally replaces any map specified for the same variable in | |
645 | @code{minor-mode-map-alist}. | |
f9f59935 | 646 | |
969fe9b5 RS |
647 | @code{minor-mode-overriding-map-alist} is automatically buffer-local in |
648 | all buffers. | |
87b2d5ff | 649 | @end defvar |
73804d4b | 650 | |
87b2d5ff RS |
651 | @defvar overriding-local-map |
652 | If non-@code{nil}, this variable holds a keymap to use instead of the | |
653 | buffer's local keymap and instead of all the minor mode keymaps. This | |
654 | keymap, if any, overrides all other maps that would have been active, | |
655 | except for the current global map. | |
73804d4b RS |
656 | @end defvar |
657 | ||
5fe8e44d RS |
658 | @defvar overriding-terminal-local-map |
659 | If non-@code{nil}, this variable holds a keymap to use instead of | |
660 | @code{overriding-local-map}, the buffer's local keymap and all the minor | |
661 | mode keymaps. | |
662 | ||
663 | This variable is always local to the current terminal and cannot be | |
664 | buffer-local. @xref{Multiple Displays}. It is used to implement | |
665 | incremental search mode. | |
666 | @end defvar | |
667 | ||
4b4b65a6 RS |
668 | @defvar overriding-local-map-menu-flag |
669 | If this variable is non-@code{nil}, the value of | |
670 | @code{overriding-local-map} or @code{overriding-terminal-local-map} can | |
671 | affect the display of the menu bar. The default value is @code{nil}, so | |
672 | those map variables have no effect on the menu bar. | |
673 | ||
674 | Note that these two map variables do affect the execution of key | |
675 | sequences entered using the menu bar, even if they do not affect the | |
676 | menu bar display. So if a menu bar key sequence comes in, you should | |
677 | clear the variables before looking up and executing that key sequence. | |
678 | Modes that use the variables would typically do this anyway; normally | |
679 | they respond to events that they do not handle by ``unreading'' them and | |
680 | exiting. | |
681 | @end defvar | |
682 | ||
f9f59935 RS |
683 | @defvar special-event-map |
684 | This variable holds a keymap for special events. If an event type has a | |
685 | binding in this keymap, then it is special, and the binding for the | |
686 | event is run directly by @code{read-event}. @xref{Special Events}. | |
687 | @end defvar | |
688 | ||
87b2d5ff RS |
689 | @node Key Lookup |
690 | @section Key Lookup | |
691 | @cindex key lookup | |
692 | @cindex keymap entry | |
73804d4b | 693 | |
87b2d5ff RS |
694 | @dfn{Key lookup} is the process of finding the binding of a key |
695 | sequence from a given keymap. Actual execution of the binding is not | |
696 | part of key lookup. | |
73804d4b | 697 | |
f9f59935 RS |
698 | Key lookup uses just the event type of each event in the key sequence; |
699 | the rest of the event is ignored. In fact, a key sequence used for key | |
700 | lookup may designate mouse events with just their types (symbols) | |
701 | instead of with entire mouse events (lists). @xref{Input Events}. Such | |
702 | a ``key-sequence'' is insufficient for @code{command-execute} to run, | |
703 | but it is sufficient for looking up or rebinding a key. | |
73804d4b | 704 | |
87b2d5ff RS |
705 | When the key sequence consists of multiple events, key lookup |
706 | processes the events sequentially: the binding of the first event is | |
707 | found, and must be a keymap; then the second event's binding is found in | |
708 | that keymap, and so on until all the events in the key sequence are used | |
709 | up. (The binding thus found for the last event may or may not be a | |
710 | keymap.) Thus, the process of key lookup is defined in terms of a | |
711 | simpler process for looking up a single event in a keymap. How that is | |
712 | done depends on the type of object associated with the event in that | |
713 | keymap. | |
73804d4b | 714 | |
87b2d5ff RS |
715 | Let's use the term @dfn{keymap entry} to describe the value found by |
716 | looking up an event type in a keymap. (This doesn't include the item | |
969fe9b5 | 717 | string and other extra elements in menu key bindings, because |
87b2d5ff RS |
718 | @code{lookup-key} and other key lookup functions don't include them in |
719 | the returned value.) While any Lisp object may be stored in a keymap as | |
969fe9b5 | 720 | a keymap entry, not all make sense for key lookup. Here is a table of |
87b2d5ff | 721 | the meaningful kinds of keymap entries: |
73804d4b | 722 | |
87b2d5ff RS |
723 | @table @asis |
724 | @item @code{nil} | |
725 | @cindex @code{nil} in keymap | |
726 | @code{nil} means that the events used so far in the lookup form an | |
727 | undefined key. When a keymap fails to mention an event type at all, and | |
728 | has no default binding, that is equivalent to a binding of @code{nil} | |
729 | for that event type. | |
73804d4b | 730 | |
87b2d5ff RS |
731 | @item @var{command} |
732 | @cindex command in keymap | |
733 | The events used so far in the lookup form a complete key, | |
734 | and @var{command} is its binding. @xref{What Is a Function}. | |
73804d4b | 735 | |
bfe721d1 | 736 | @item @var{array} |
87b2d5ff | 737 | @cindex string in keymap |
bfe721d1 KH |
738 | The array (either a string or a vector) is a keyboard macro. The events |
739 | used so far in the lookup form a complete key, and the array is its | |
740 | binding. See @ref{Keyboard Macros}, for more information. | |
73804d4b | 741 | |
969fe9b5 RS |
742 | @item @var{keymap} |
743 | @cindex keymap in keymap | |
744 | The events used so far in the lookup form a prefix key. The next | |
745 | event of the key sequence is looked up in @var{keymap}. | |
746 | ||
87b2d5ff RS |
747 | @item @var{list} |
748 | @cindex list in keymap | |
749 | The meaning of a list depends on the types of the elements of the list. | |
73804d4b | 750 | |
87b2d5ff RS |
751 | @itemize @bullet |
752 | @item | |
753 | If the @sc{car} of @var{list} is the symbol @code{keymap}, then the list | |
754 | is a keymap, and is treated as a keymap (see above). | |
73804d4b | 755 | |
87b2d5ff RS |
756 | @item |
757 | @cindex @code{lambda} in keymap | |
758 | If the @sc{car} of @var{list} is @code{lambda}, then the list is a | |
759 | lambda expression. This is presumed to be a command, and is treated as | |
760 | such (see above). | |
73804d4b | 761 | |
87b2d5ff RS |
762 | @item |
763 | If the @sc{car} of @var{list} is a keymap and the @sc{cdr} is an event | |
764 | type, then this is an @dfn{indirect entry}: | |
73804d4b RS |
765 | |
766 | @example | |
87b2d5ff | 767 | (@var{othermap} . @var{othertype}) |
73804d4b RS |
768 | @end example |
769 | ||
87b2d5ff RS |
770 | When key lookup encounters an indirect entry, it looks up instead the |
771 | binding of @var{othertype} in @var{othermap} and uses that. | |
73804d4b | 772 | |
87b2d5ff RS |
773 | This feature permits you to define one key as an alias for another key. |
774 | For example, an entry whose @sc{car} is the keymap called @code{esc-map} | |
bfe721d1 | 775 | and whose @sc{cdr} is 32 (the code for @key{SPC}) means, ``Use the global |
87b2d5ff RS |
776 | binding of @kbd{Meta-@key{SPC}}, whatever that may be.'' |
777 | @end itemize | |
73804d4b | 778 | |
87b2d5ff RS |
779 | @item @var{symbol} |
780 | @cindex symbol in keymap | |
781 | The function definition of @var{symbol} is used in place of | |
782 | @var{symbol}. If that too is a symbol, then this process is repeated, | |
783 | any number of times. Ultimately this should lead to an object that is | |
f9f59935 | 784 | a keymap, a command, or a keyboard macro. A list is allowed if it is a |
87b2d5ff RS |
785 | keymap or a command, but indirect entries are not understood when found |
786 | via symbols. | |
73804d4b | 787 | |
87b2d5ff RS |
788 | Note that keymaps and keyboard macros (strings and vectors) are not |
789 | valid functions, so a symbol with a keymap, string, or vector as its | |
790 | function definition is invalid as a function. It is, however, valid as | |
791 | a key binding. If the definition is a keyboard macro, then the symbol | |
792 | is also valid as an argument to @code{command-execute} | |
793 | (@pxref{Interactive Call}). | |
73804d4b | 794 | |
87b2d5ff RS |
795 | @cindex @code{undefined} in keymap |
796 | The symbol @code{undefined} is worth special mention: it means to treat | |
797 | the key as undefined. Strictly speaking, the key is defined, and its | |
798 | binding is the command @code{undefined}; but that command does the same | |
799 | thing that is done automatically for an undefined key: it rings the bell | |
800 | (by calling @code{ding}) but does not signal an error. | |
73804d4b | 801 | |
87b2d5ff RS |
802 | @cindex preventing prefix key |
803 | @code{undefined} is used in local keymaps to override a global key | |
804 | binding and make the key ``undefined'' locally. A local binding of | |
805 | @code{nil} would fail to do this because it would not override the | |
806 | global binding. | |
807 | ||
808 | @item @var{anything else} | |
809 | If any other type of object is found, the events used so far in the | |
810 | lookup form a complete key, and the object is its binding, but the | |
811 | binding is not executable as a command. | |
812 | @end table | |
813 | ||
814 | In short, a keymap entry may be a keymap, a command, a keyboard macro, | |
815 | a symbol that leads to one of them, or an indirection or @code{nil}. | |
816 | Here is an example of a sparse keymap with two characters bound to | |
817 | commands and one bound to another keymap. This map is the normal value | |
818 | of @code{emacs-lisp-mode-map}. Note that 9 is the code for @key{TAB}, | |
819 | 127 for @key{DEL}, 27 for @key{ESC}, 17 for @kbd{C-q} and 24 for | |
820 | @kbd{C-x}. | |
73804d4b RS |
821 | |
822 | @example | |
87b2d5ff RS |
823 | @group |
824 | (keymap (9 . lisp-indent-line) | |
825 | (127 . backward-delete-char-untabify) | |
826 | (27 keymap (17 . indent-sexp) (24 . eval-defun))) | |
827 | @end group | |
73804d4b RS |
828 | @end example |
829 | ||
87b2d5ff RS |
830 | @node Functions for Key Lookup |
831 | @section Functions for Key Lookup | |
73804d4b | 832 | |
87b2d5ff | 833 | Here are the functions and variables pertaining to key lookup. |
73804d4b | 834 | |
87b2d5ff | 835 | @defun lookup-key keymap key &optional accept-defaults |
969fe9b5 RS |
836 | This function returns the definition of @var{key} in @var{keymap}. All |
837 | the other functions described in this chapter that look up keys use | |
838 | @code{lookup-key}. Here are examples: | |
73804d4b | 839 | |
87b2d5ff RS |
840 | @example |
841 | @group | |
842 | (lookup-key (current-global-map) "\C-x\C-f") | |
843 | @result{} find-file | |
844 | @end group | |
845 | @group | |
846 | (lookup-key (current-global-map) "\C-x\C-f12345") | |
847 | @result{} 2 | |
848 | @end group | |
849 | @end example | |
73804d4b | 850 | |
969fe9b5 RS |
851 | If the string or vector @var{key} is not a valid key sequence according |
852 | to the prefix keys specified in @var{keymap}, it must be ``too long'' | |
853 | and have extra events at the end that do not fit into a single key | |
854 | sequence. Then the value is a number, the number of events at the front | |
855 | of @var{key} that compose a complete key. | |
856 | ||
857 | @c Emacs 19 feature | |
858 | If @var{accept-defaults} is non-@code{nil}, then @code{lookup-key} | |
859 | considers default bindings as well as bindings for the specific events | |
860 | in @var{key}. Otherwise, @code{lookup-key} reports only bindings for | |
861 | the specific sequence @var{key}, ignoring default bindings except when | |
862 | you explicitly ask about them. (To do this, supply @code{t} as an | |
863 | element of @var{key}; see @ref{Format of Keymaps}.) | |
864 | ||
865 | If @var{key} contains a meta character, that character is implicitly | |
87b2d5ff RS |
866 | replaced by a two-character sequence: the value of |
867 | @code{meta-prefix-char}, followed by the corresponding non-meta | |
868 | character. Thus, the first example below is handled by conversion into | |
869 | the second example. | |
73804d4b RS |
870 | |
871 | @example | |
872 | @group | |
87b2d5ff RS |
873 | (lookup-key (current-global-map) "\M-f") |
874 | @result{} forward-word | |
875 | @end group | |
876 | @group | |
877 | (lookup-key (current-global-map) "\ef") | |
878 | @result{} forward-word | |
73804d4b RS |
879 | @end group |
880 | @end example | |
87b2d5ff RS |
881 | |
882 | Unlike @code{read-key-sequence}, this function does not modify the | |
883 | specified events in ways that discard information (@pxref{Key Sequence | |
884 | Input}). In particular, it does not convert letters to lower case and | |
885 | it does not change drag events to clicks. | |
73804d4b RS |
886 | @end defun |
887 | ||
87b2d5ff RS |
888 | @deffn Command undefined |
889 | Used in keymaps to undefine keys. It calls @code{ding}, but does | |
890 | not cause an error. | |
891 | @end deffn | |
892 | ||
893 | @defun key-binding key &optional accept-defaults | |
894 | This function returns the binding for @var{key} in the current | |
895 | keymaps, trying all the active keymaps. The result is @code{nil} if | |
896 | @var{key} is undefined in the keymaps. | |
897 | ||
898 | @c Emacs 19 feature | |
899 | The argument @var{accept-defaults} controls checking for default | |
900 | bindings, as in @code{lookup-key} (above). | |
901 | ||
902 | An error is signaled if @var{key} is not a string or a vector. | |
73804d4b RS |
903 | |
904 | @example | |
905 | @group | |
87b2d5ff RS |
906 | (key-binding "\C-x\C-f") |
907 | @result{} find-file | |
73804d4b RS |
908 | @end group |
909 | @end example | |
910 | @end defun | |
911 | ||
87b2d5ff RS |
912 | @defun local-key-binding key &optional accept-defaults |
913 | This function returns the binding for @var{key} in the current | |
914 | local keymap, or @code{nil} if it is undefined there. | |
73804d4b | 915 | |
87b2d5ff RS |
916 | @c Emacs 19 feature |
917 | The argument @var{accept-defaults} controls checking for default bindings, | |
918 | as in @code{lookup-key} (above). | |
73804d4b RS |
919 | @end defun |
920 | ||
87b2d5ff RS |
921 | @defun global-key-binding key &optional accept-defaults |
922 | This function returns the binding for command @var{key} in the | |
923 | current global keymap, or @code{nil} if it is undefined there. | |
73804d4b RS |
924 | |
925 | @c Emacs 19 feature | |
87b2d5ff RS |
926 | The argument @var{accept-defaults} controls checking for default bindings, |
927 | as in @code{lookup-key} (above). | |
928 | @end defun | |
73804d4b | 929 | |
87b2d5ff RS |
930 | @c Emacs 19 feature |
931 | @defun minor-mode-key-binding key &optional accept-defaults | |
932 | This function returns a list of all the active minor mode bindings of | |
933 | @var{key}. More precisely, it returns an alist of pairs | |
934 | @code{(@var{modename} . @var{binding})}, where @var{modename} is the | |
935 | variable that enables the minor mode, and @var{binding} is @var{key}'s | |
936 | binding in that mode. If @var{key} has no minor-mode bindings, the | |
937 | value is @code{nil}. | |
73804d4b | 938 | |
f9f59935 RS |
939 | If the first binding found is not a prefix definition (a keymap or a |
940 | symbol defined as a keymap), all subsequent bindings from other minor | |
941 | modes are omitted, since they would be completely shadowed. Similarly, | |
942 | the list omits non-prefix bindings that follow prefix bindings. | |
73804d4b | 943 | |
87b2d5ff RS |
944 | The argument @var{accept-defaults} controls checking for default |
945 | bindings, as in @code{lookup-key} (above). | |
946 | @end defun | |
73804d4b | 947 | |
87b2d5ff RS |
948 | @defvar meta-prefix-char |
949 | @cindex @key{ESC} | |
950 | This variable is the meta-prefix character code. It is used when | |
951 | translating a meta character to a two-character sequence so it can be | |
952 | looked up in a keymap. For useful results, the value should be a prefix | |
953 | event (@pxref{Prefix Keys}). The default value is 27, which is the | |
954 | @sc{ASCII} code for @key{ESC}. | |
73804d4b | 955 | |
87b2d5ff RS |
956 | As long as the value of @code{meta-prefix-char} remains 27, key |
957 | lookup translates @kbd{M-b} into @kbd{@key{ESC} b}, which is normally | |
958 | defined as the @code{backward-word} command. However, if you set | |
959 | @code{meta-prefix-char} to 24, the code for @kbd{C-x}, then Emacs will | |
960 | translate @kbd{M-b} into @kbd{C-x b}, whose standard binding is the | |
969fe9b5 | 961 | @code{switch-to-buffer} command. Here is an illustration: |
73804d4b | 962 | |
87b2d5ff RS |
963 | @smallexample |
964 | @group | |
965 | meta-prefix-char ; @r{The default value.} | |
966 | @result{} 27 | |
967 | @end group | |
968 | @group | |
969 | (key-binding "\M-b") | |
970 | @result{} backward-word | |
971 | @end group | |
972 | @group | |
973 | ?\C-x ; @r{The print representation} | |
974 | @result{} 24 ; @r{of a character.} | |
975 | @end group | |
976 | @group | |
977 | (setq meta-prefix-char 24) | |
978 | @result{} 24 | |
979 | @end group | |
980 | @group | |
981 | (key-binding "\M-b") | |
982 | @result{} switch-to-buffer ; @r{Now, typing @kbd{M-b} is} | |
983 | ; @r{like typing @kbd{C-x b}.} | |
73804d4b | 984 | |
87b2d5ff RS |
985 | (setq meta-prefix-char 27) ; @r{Avoid confusion!} |
986 | @result{} 27 ; @r{Restore the default value!} | |
987 | @end group | |
988 | @end smallexample | |
73804d4b RS |
989 | @end defvar |
990 | ||
87b2d5ff RS |
991 | @node Changing Key Bindings |
992 | @section Changing Key Bindings | |
993 | @cindex changing key bindings | |
994 | @cindex rebinding | |
73804d4b | 995 | |
87b2d5ff RS |
996 | The way to rebind a key is to change its entry in a keymap. If you |
997 | change a binding in the global keymap, the change is effective in all | |
998 | buffers (though it has no direct effect in buffers that shadow the | |
999 | global binding with a local one). If you change the current buffer's | |
1000 | local map, that usually affects all buffers using the same major mode. | |
1001 | The @code{global-set-key} and @code{local-set-key} functions are | |
1002 | convenient interfaces for these operations (@pxref{Key Binding | |
1003 | Commands}). You can also use @code{define-key}, a more general | |
1004 | function; then you must specify explicitly the map to change. | |
73804d4b | 1005 | |
87b2d5ff RS |
1006 | @cindex meta character key constants |
1007 | @cindex control character key constants | |
1008 | In writing the key sequence to rebind, it is good to use the special | |
1009 | escape sequences for control and meta characters (@pxref{String Type}). | |
1010 | The syntax @samp{\C-} means that the following character is a control | |
1011 | character and @samp{\M-} means that the following character is a meta | |
1012 | character. Thus, the string @code{"\M-x"} is read as containing a | |
1013 | single @kbd{M-x}, @code{"\C-f"} is read as containing a single | |
1014 | @kbd{C-f}, and @code{"\M-\C-x"} and @code{"\C-\M-x"} are both read as | |
1015 | containing a single @kbd{C-M-x}. You can also use this escape syntax in | |
1016 | vectors, as well as others that aren't allowed in strings; one example | |
1017 | is @samp{[?\C-\H-x home]}. @xref{Character Type}. | |
73804d4b | 1018 | |
22697dac KH |
1019 | The key definition and lookup functions accept an alternate syntax for |
1020 | event types in a key sequence that is a vector: you can use a list | |
1021 | containing modifier names plus one base event (a character or function | |
1022 | key name). For example, @code{(control ?a)} is equivalent to | |
1023 | @code{?\C-a} and @code{(hyper control left)} is equivalent to | |
969fe9b5 RS |
1024 | @code{C-H-left}. One advantage of such lists is that the precise |
1025 | numeric codes for the modifier bits don't appear in compiled files. | |
bfe721d1 | 1026 | |
87b2d5ff RS |
1027 | For the functions below, an error is signaled if @var{keymap} is not a |
1028 | keymap or if @var{key} is not a string or vector representing a key | |
1029 | sequence. You can use event types (symbols) as shorthand for events | |
1030 | that are lists. | |
73804d4b | 1031 | |
87b2d5ff RS |
1032 | @defun define-key keymap key binding |
1033 | This function sets the binding for @var{key} in @var{keymap}. (If | |
1034 | @var{key} is more than one event long, the change is actually made | |
1035 | in another keymap reached from @var{keymap}.) The argument | |
1036 | @var{binding} can be any Lisp object, but only certain types are | |
1037 | meaningful. (For a list of meaningful types, see @ref{Key Lookup}.) | |
1038 | The value returned by @code{define-key} is @var{binding}. | |
73804d4b | 1039 | |
87b2d5ff RS |
1040 | @cindex invalid prefix key error |
1041 | @cindex key sequence error | |
969fe9b5 RS |
1042 | Every prefix of @var{key} must be a prefix key (i.e., bound to a keymap) |
1043 | or undefined; otherwise an error is signaled. If some prefix of | |
1044 | @var{key} is undefined, then @code{define-key} defines it as a prefix | |
1045 | key so that the rest of @var{key} can be defined as specified. | |
f9f59935 RS |
1046 | |
1047 | If there was previously no binding for @var{key} in @var{keymap}, the | |
1048 | new binding is added at the beginning of @var{keymap}. The order of | |
1049 | bindings in a keymap makes no difference in most cases, but it does | |
1050 | matter for menu keymaps (@pxref{Menu Keymaps}). | |
87b2d5ff | 1051 | @end defun |
73804d4b | 1052 | |
87b2d5ff RS |
1053 | Here is an example that creates a sparse keymap and makes a number of |
1054 | bindings in it: | |
73804d4b | 1055 | |
87b2d5ff | 1056 | @smallexample |
73804d4b | 1057 | @group |
87b2d5ff RS |
1058 | (setq map (make-sparse-keymap)) |
1059 | @result{} (keymap) | |
73804d4b | 1060 | @end group |
73804d4b | 1061 | @group |
87b2d5ff RS |
1062 | (define-key map "\C-f" 'forward-char) |
1063 | @result{} forward-char | |
73804d4b RS |
1064 | @end group |
1065 | @group | |
87b2d5ff RS |
1066 | map |
1067 | @result{} (keymap (6 . forward-char)) | |
73804d4b | 1068 | @end group |
73804d4b | 1069 | |
73804d4b | 1070 | @group |
87b2d5ff RS |
1071 | ;; @r{Build sparse submap for @kbd{C-x} and bind @kbd{f} in that.} |
1072 | (define-key map "\C-xf" 'forward-word) | |
73804d4b RS |
1073 | @result{} forward-word |
1074 | @end group | |
1075 | @group | |
87b2d5ff RS |
1076 | map |
1077 | @result{} (keymap | |
1078 | (24 keymap ; @kbd{C-x} | |
1079 | (102 . forward-word)) ; @kbd{f} | |
1080 | (6 . forward-char)) ; @kbd{C-f} | |
73804d4b | 1081 | @end group |
73804d4b | 1082 | |
87b2d5ff RS |
1083 | @group |
1084 | ;; @r{Bind @kbd{C-p} to the @code{ctl-x-map}.} | |
1085 | (define-key map "\C-p" ctl-x-map) | |
1086 | ;; @code{ctl-x-map} | |
1087 | @result{} [nil @dots{} find-file @dots{} backward-kill-sentence] | |
1088 | @end group | |
73804d4b | 1089 | |
73804d4b | 1090 | @group |
87b2d5ff RS |
1091 | ;; @r{Bind @kbd{C-f} to @code{foo} in the @code{ctl-x-map}.} |
1092 | (define-key map "\C-p\C-f" 'foo) | |
1093 | @result{} 'foo | |
73804d4b | 1094 | @end group |
87b2d5ff RS |
1095 | @group |
1096 | map | |
1097 | @result{} (keymap ; @r{Note @code{foo} in @code{ctl-x-map}.} | |
1098 | (16 keymap [nil @dots{} foo @dots{} backward-kill-sentence]) | |
1099 | (24 keymap | |
1100 | (102 . forward-word)) | |
1101 | (6 . forward-char)) | |
1102 | @end group | |
1103 | @end smallexample | |
73804d4b | 1104 | |
87b2d5ff RS |
1105 | @noindent |
1106 | Note that storing a new binding for @kbd{C-p C-f} actually works by | |
1107 | changing an entry in @code{ctl-x-map}, and this has the effect of | |
1108 | changing the bindings of both @kbd{C-p C-f} and @kbd{C-x C-f} in the | |
1109 | default global map. | |
73804d4b | 1110 | |
87b2d5ff RS |
1111 | @defun substitute-key-definition olddef newdef keymap &optional oldmap |
1112 | @cindex replace bindings | |
1113 | This function replaces @var{olddef} with @var{newdef} for any keys in | |
1114 | @var{keymap} that were bound to @var{olddef}. In other words, | |
1115 | @var{olddef} is replaced with @var{newdef} wherever it appears. The | |
1116 | function returns @code{nil}. | |
73804d4b | 1117 | |
87b2d5ff RS |
1118 | For example, this redefines @kbd{C-x C-f}, if you do it in an Emacs with |
1119 | standard bindings: | |
73804d4b | 1120 | |
87b2d5ff RS |
1121 | @smallexample |
1122 | @group | |
1123 | (substitute-key-definition | |
1124 | 'find-file 'find-file-read-only (current-global-map)) | |
1125 | @end group | |
1126 | @end smallexample | |
73804d4b RS |
1127 | |
1128 | @c Emacs 19 feature | |
87b2d5ff | 1129 | If @var{oldmap} is non-@code{nil}, then its bindings determine which |
3d3af498 | 1130 | keys to rebind. The rebindings still happen in @var{keymap}, not in |
87b2d5ff RS |
1131 | @var{oldmap}. Thus, you can change one map under the control of the |
1132 | bindings in another. For example, | |
73804d4b | 1133 | |
87b2d5ff RS |
1134 | @smallexample |
1135 | (substitute-key-definition | |
1136 | 'delete-backward-char 'my-funny-delete | |
1137 | my-map global-map) | |
1138 | @end smallexample | |
73804d4b | 1139 | |
87b2d5ff RS |
1140 | @noindent |
1141 | puts the special deletion command in @code{my-map} for whichever keys | |
1142 | are globally bound to the standard deletion command. | |
73804d4b | 1143 | |
87b2d5ff RS |
1144 | @ignore |
1145 | @c Emacs 18 only | |
1146 | Prefix keymaps that appear within @var{keymap} are not checked | |
1147 | recursively for keys bound to @var{olddef}; they are not changed at all. | |
1148 | Perhaps it would be better to check nested keymaps recursively. | |
1149 | @end ignore | |
73804d4b | 1150 | |
87b2d5ff | 1151 | Here is an example showing a keymap before and after substitution: |
73804d4b RS |
1152 | |
1153 | @smallexample | |
1154 | @group | |
1155 | (setq map '(keymap | |
1156 | (?1 . olddef-1) | |
1157 | (?2 . olddef-2) | |
1158 | (?3 . olddef-1))) | |
1159 | @result{} (keymap (49 . olddef-1) (50 . olddef-2) (51 . olddef-1)) | |
1160 | @end group | |
1161 | ||
1162 | @group | |
1163 | (substitute-key-definition 'olddef-1 'newdef map) | |
1164 | @result{} nil | |
1165 | @end group | |
1166 | @group | |
1167 | map | |
1168 | @result{} (keymap (49 . newdef) (50 . olddef-2) (51 . newdef)) | |
1169 | @end group | |
1170 | @end smallexample | |
1171 | @end defun | |
1172 | ||
1173 | @defun suppress-keymap keymap &optional nodigits | |
1174 | @cindex @code{self-insert-command} override | |
1175 | This function changes the contents of the full keymap @var{keymap} by | |
1176 | making all the printing characters undefined. More precisely, it binds | |
1177 | them to the command @code{undefined}. This makes ordinary insertion of | |
1178 | text impossible. @code{suppress-keymap} returns @code{nil}. | |
1179 | ||
1180 | If @var{nodigits} is @code{nil}, then @code{suppress-keymap} defines | |
1181 | digits to run @code{digit-argument}, and @kbd{-} to run | |
1182 | @code{negative-argument}. Otherwise it makes them undefined like the | |
1183 | rest of the printing characters. | |
1184 | ||
1185 | @cindex yank suppression | |
1186 | @cindex @code{quoted-insert} suppression | |
1187 | The @code{suppress-keymap} function does not make it impossible to | |
1188 | modify a buffer, as it does not suppress commands such as @code{yank} | |
1189 | and @code{quoted-insert}. To prevent any modification of a buffer, make | |
1190 | it read-only (@pxref{Read Only Buffers}). | |
1191 | ||
1192 | Since this function modifies @var{keymap}, you would normally use it | |
1193 | on a newly created keymap. Operating on an existing keymap | |
1194 | that is used for some other purpose is likely to cause trouble; for | |
1195 | example, suppressing @code{global-map} would make it impossible to use | |
1196 | most of Emacs. | |
1197 | ||
1198 | Most often, @code{suppress-keymap} is used to initialize local | |
1199 | keymaps of modes such as Rmail and Dired where insertion of text is not | |
1200 | desirable and the buffer is read-only. Here is an example taken from | |
1201 | the file @file{emacs/lisp/dired.el}, showing how the local keymap for | |
1202 | Dired mode is set up: | |
1203 | ||
1204 | @smallexample | |
1205 | @group | |
1911e6e5 RS |
1206 | (setq dired-mode-map (make-keymap)) |
1207 | (suppress-keymap dired-mode-map) | |
1208 | (define-key dired-mode-map "r" 'dired-rename-file) | |
1209 | (define-key dired-mode-map "\C-d" 'dired-flag-file-deleted) | |
1210 | (define-key dired-mode-map "d" 'dired-flag-file-deleted) | |
1211 | (define-key dired-mode-map "v" 'dired-view-file) | |
1212 | (define-key dired-mode-map "e" 'dired-find-file) | |
1213 | (define-key dired-mode-map "f" 'dired-find-file) | |
1214 | @dots{} | |
73804d4b RS |
1215 | @end group |
1216 | @end smallexample | |
1217 | @end defun | |
1218 | ||
1219 | @node Key Binding Commands | |
1220 | @section Commands for Binding Keys | |
1221 | ||
1222 | This section describes some convenient interactive interfaces for | |
1223 | changing key bindings. They work by calling @code{define-key}. | |
1224 | ||
87b2d5ff RS |
1225 | People often use @code{global-set-key} in their @file{.emacs} file for |
1226 | simple customization. For example, | |
1227 | ||
1228 | @smallexample | |
1229 | (global-set-key "\C-x\C-\\" 'next-line) | |
1230 | @end smallexample | |
1231 | ||
1232 | @noindent | |
1233 | or | |
1234 | ||
1235 | @smallexample | |
1236 | (global-set-key [?\C-x ?\C-\\] 'next-line) | |
1237 | @end smallexample | |
1238 | ||
bfe721d1 KH |
1239 | @noindent |
1240 | or | |
1241 | ||
1242 | @smallexample | |
1243 | (global-set-key [(control ?x) (control ?\\)] 'next-line) | |
1244 | @end smallexample | |
1245 | ||
87b2d5ff RS |
1246 | @noindent |
1247 | redefines @kbd{C-x C-\} to move down a line. | |
1248 | ||
1249 | @smallexample | |
1250 | (global-set-key [M-mouse-1] 'mouse-set-point) | |
1251 | @end smallexample | |
1252 | ||
1253 | @noindent | |
1254 | redefines the first (leftmost) mouse button, typed with the Meta key, to | |
1255 | set point where you click. | |
1256 | ||
73804d4b | 1257 | @deffn Command global-set-key key definition |
87b2d5ff | 1258 | This function sets the binding of @var{key} in the current global map |
73804d4b RS |
1259 | to @var{definition}. |
1260 | ||
1261 | @smallexample | |
1262 | @group | |
1263 | (global-set-key @var{key} @var{definition}) | |
1264 | @equiv{} | |
1265 | (define-key (current-global-map) @var{key} @var{definition}) | |
1266 | @end group | |
1267 | @end smallexample | |
1268 | @end deffn | |
1269 | ||
1270 | @deffn Command global-unset-key key | |
1271 | @cindex unbinding keys | |
87b2d5ff | 1272 | This function removes the binding of @var{key} from the current |
73804d4b RS |
1273 | global map. |
1274 | ||
87b2d5ff RS |
1275 | One use of this function is in preparation for defining a longer key |
1276 | that uses @var{key} as a prefix---which would not be allowed if | |
1277 | @var{key} has a non-prefix binding. For example: | |
1278 | ||
1279 | @smallexample | |
1280 | @group | |
1281 | (global-unset-key "\C-l") | |
1282 | @result{} nil | |
1283 | @end group | |
1284 | @group | |
1285 | (global-set-key "\C-l\C-l" 'redraw-display) | |
1286 | @result{} nil | |
1287 | @end group | |
1288 | @end smallexample | |
1289 | ||
1290 | This function is implemented simply using @code{define-key}: | |
1291 | ||
1292 | @smallexample | |
1293 | @group | |
1294 | (global-unset-key @var{key}) | |
1295 | @equiv{} | |
1296 | (define-key (current-global-map) @var{key} nil) | |
1297 | @end group | |
1298 | @end smallexample | |
1299 | @end deffn | |
1300 | ||
1301 | @deffn Command local-set-key key definition | |
1302 | This function sets the binding of @var{key} in the current local | |
1303 | keymap to @var{definition}. | |
1304 | ||
1305 | @smallexample | |
1306 | @group | |
1307 | (local-set-key @var{key} @var{definition}) | |
1308 | @equiv{} | |
1309 | (define-key (current-local-map) @var{key} @var{definition}) | |
1310 | @end group | |
1311 | @end smallexample | |
1312 | @end deffn | |
1313 | ||
1314 | @deffn Command local-unset-key key | |
1315 | This function removes the binding of @var{key} from the current | |
1316 | local map. | |
1317 | ||
1318 | @smallexample | |
1319 | @group | |
1320 | (local-unset-key @var{key}) | |
1321 | @equiv{} | |
1322 | (define-key (current-local-map) @var{key} nil) | |
1323 | @end group | |
1324 | @end smallexample | |
1325 | @end deffn | |
1326 | ||
1327 | @node Scanning Keymaps | |
1328 | @section Scanning Keymaps | |
1329 | ||
1330 | This section describes functions used to scan all the current keymaps | |
1331 | for the sake of printing help information. | |
1332 | ||
1333 | @defun accessible-keymaps keymap &optional prefix | |
f9f59935 RS |
1334 | This function returns a list of all the keymaps that can be reached (via |
1335 | zero or more prefix keys) from @var{keymap}. The value is an | |
1336 | association list with elements of the form @code{(@var{key} .@: | |
1337 | @var{map})}, where @var{key} is a prefix key whose definition in | |
1338 | @var{keymap} is @var{map}. | |
87b2d5ff RS |
1339 | |
1340 | The elements of the alist are ordered so that the @var{key} increases | |
1341 | in length. The first element is always @code{("" .@: @var{keymap})}, | |
1342 | because the specified keymap is accessible from itself with a prefix of | |
1343 | no events. | |
1344 | ||
1345 | If @var{prefix} is given, it should be a prefix key sequence; then | |
1346 | @code{accessible-keymaps} includes only the submaps whose prefixes start | |
1347 | with @var{prefix}. These elements look just as they do in the value of | |
1348 | @code{(accessible-keymaps)}; the only difference is that some elements | |
1349 | are omitted. | |
1350 | ||
1351 | In the example below, the returned alist indicates that the key | |
1352 | @key{ESC}, which is displayed as @samp{^[}, is a prefix key whose | |
1353 | definition is the sparse keymap @code{(keymap (83 .@: center-paragraph) | |
1354 | (115 .@: foo))}. | |
1355 | ||
1356 | @smallexample | |
1357 | @group | |
1358 | (accessible-keymaps (current-local-map)) | |
1359 | @result{}(("" keymap | |
1360 | (27 keymap ; @r{Note this keymap for @key{ESC} is repeated below.} | |
1361 | (83 . center-paragraph) | |
1362 | (115 . center-line)) | |
1363 | (9 . tab-to-tab-stop)) | |
1364 | @end group | |
1365 | ||
1366 | @group | |
1367 | ("^[" keymap | |
1368 | (83 . center-paragraph) | |
1369 | (115 . foo))) | |
1370 | @end group | |
1371 | @end smallexample | |
1372 | ||
1373 | In the following example, @kbd{C-h} is a prefix key that uses a sparse | |
1374 | keymap starting with @code{(keymap (118 . describe-variable)@dots{})}. | |
1375 | Another prefix, @kbd{C-x 4}, uses a keymap which is also the value of | |
1376 | the variable @code{ctl-x-4-map}. The event @code{mode-line} is one of | |
1377 | several dummy events used as prefixes for mouse actions in special parts | |
1378 | of a window. | |
1379 | ||
1380 | @smallexample | |
1381 | @group | |
1382 | (accessible-keymaps (current-global-map)) | |
1383 | @result{} (("" keymap [set-mark-command beginning-of-line @dots{} | |
1384 | delete-backward-char]) | |
1385 | @end group | |
1386 | @group | |
1387 | ("^H" keymap (118 . describe-variable) @dots{} | |
1388 | (8 . help-for-help)) | |
1389 | @end group | |
1390 | @group | |
1391 | ("^X" keymap [x-flush-mouse-queue @dots{} | |
1392 | backward-kill-sentence]) | |
1393 | @end group | |
1394 | @group | |
1395 | ("^[" keymap [mark-sexp backward-sexp @dots{} | |
1396 | backward-kill-word]) | |
1397 | @end group | |
1398 | ("^X4" keymap (15 . display-buffer) @dots{}) | |
1399 | @group | |
1400 | ([mode-line] keymap | |
1401 | (S-mouse-2 . mouse-split-window-horizontally) @dots{})) | |
1402 | @end group | |
1403 | @end smallexample | |
1404 | ||
1405 | @noindent | |
969fe9b5 | 1406 | These are not all the keymaps you would see in actuality. |
87b2d5ff RS |
1407 | @end defun |
1408 | ||
1409 | @defun where-is-internal command &optional keymap firstonly noindirect | |
f9f59935 RS |
1410 | This function is a subroutine used by the @code{where-is} command |
1411 | (@pxref{Help, , Help, emacs,The GNU Emacs Manual}). It returns a list | |
1412 | of key sequences (of any length) that are bound to @var{command} in a | |
1413 | set of keymaps. | |
87b2d5ff RS |
1414 | |
1415 | The argument @var{command} can be any object; it is compared with all | |
1416 | keymap entries using @code{eq}. | |
1417 | ||
1418 | If @var{keymap} is @code{nil}, then the maps used are the current active | |
1419 | keymaps, disregarding @code{overriding-local-map} (that is, pretending | |
1420 | its value is @code{nil}). If @var{keymap} is non-@code{nil}, then the | |
1421 | maps searched are @var{keymap} and the global keymap. | |
1422 | ||
1423 | Usually it's best to use @code{overriding-local-map} as the expression | |
1424 | for @var{keymap}. Then @code{where-is-internal} searches precisely the | |
1425 | keymaps that are active. To search only the global map, pass | |
1426 | @code{(keymap)} (an empty keymap) as @var{keymap}. | |
1427 | ||
1428 | If @var{firstonly} is @code{non-ascii}, then the value is a single | |
1429 | string representing the first key sequence found, rather than a list of | |
1430 | all possible key sequences. If @var{firstonly} is @code{t}, then the | |
1431 | value is the first key sequence, except that key sequences consisting | |
1432 | entirely of @sc{ASCII} characters (or meta variants of @sc{ASCII} | |
1433 | characters) are preferred to all other key sequences. | |
1434 | ||
1435 | If @var{noindirect} is non-@code{nil}, @code{where-is-internal} doesn't | |
1436 | follow indirect keymap bindings. This makes it possible to search for | |
1437 | an indirect definition itself. | |
1438 | ||
87b2d5ff RS |
1439 | @smallexample |
1440 | @group | |
1441 | (where-is-internal 'describe-function) | |
1442 | @result{} ("\^hf" "\^hd") | |
1443 | @end group | |
1444 | @end smallexample | |
1445 | @end defun | |
1446 | ||
a9f0a989 | 1447 | @deffn Command describe-bindings &optional prefix |
969fe9b5 RS |
1448 | This function creates a listing of all current key bindings, and |
1449 | displays it in a buffer named @samp{*Help*}. The text is grouped by | |
1450 | modes---minor modes first, then the major mode, then global bindings. | |
87b2d5ff RS |
1451 | |
1452 | If @var{prefix} is non-@code{nil}, it should be a prefix key; then the | |
1453 | listing includes only keys that start with @var{prefix}. | |
1454 | ||
1455 | The listing describes meta characters as @key{ESC} followed by the | |
1456 | corresponding non-meta character. | |
1457 | ||
1458 | When several characters with consecutive @sc{ASCII} codes have the | |
1459 | same definition, they are shown together, as | |
1460 | @samp{@var{firstchar}..@var{lastchar}}. In this instance, you need to | |
1461 | know the @sc{ASCII} codes to understand which characters this means. | |
1462 | For example, in the default global map, the characters @samp{@key{SPC} | |
1463 | ..@: ~} are described by a single line. @key{SPC} is @sc{ASCII} 32, | |
1464 | @kbd{~} is @sc{ASCII} 126, and the characters between them include all | |
1465 | the normal printing characters, (e.g., letters, digits, punctuation, | |
1466 | etc.@:); all these characters are bound to @code{self-insert-command}. | |
1467 | @end deffn | |
1468 | ||
1469 | @node Menu Keymaps | |
1470 | @section Menu Keymaps | |
1471 | @cindex menu keymaps | |
1472 | ||
1473 | @c Emacs 19 feature | |
1474 | A keymap can define a menu as well as bindings for keyboard keys and | |
1475 | mouse button. Menus are usually actuated with the mouse, but they can | |
1476 | work with the keyboard also. | |
1477 | ||
1478 | @menu | |
1479 | * Defining Menus:: How to make a keymap that defines a menu. | |
1480 | * Mouse Menus:: How users actuate the menu with the mouse. | |
1481 | * Keyboard Menus:: How they actuate it with the keyboard. | |
1482 | * Menu Example:: Making a simple menu. | |
1483 | * Menu Bar:: How to customize the menu bar. | |
1484 | * Modifying Menus:: How to add new items to a menu. | |
1485 | @end menu | |
1486 | ||
1487 | @node Defining Menus | |
1488 | @subsection Defining Menus | |
1489 | @cindex defining menus | |
1490 | @cindex menu prompt string | |
1491 | @cindex prompt string (of menu) | |
1492 | ||
1493 | A keymap is suitable for menu use if it has an @dfn{overall prompt | |
1494 | string}, which is a string that appears as an element of the keymap. | |
1495 | (@xref{Format of Keymaps}.) The string should describe the purpose of | |
1496 | the menu. The easiest way to construct a keymap with a prompt string is | |
1497 | to specify the string as an argument when you call @code{make-keymap} or | |
1498 | @code{make-sparse-keymap} (@pxref{Creating Keymaps}). | |
1499 | ||
aae60c21 RS |
1500 | The order of items in the menu is the same as the order of bindings in |
1501 | the keymap. Since @code{define-key} puts new bindings at the front, you | |
1502 | should define the menu items starting at the bottom of the menu and | |
1503 | moving to the top, if you care about the order. When you add an item to | |
1504 | an existing menu, you can specify its position in the menu using | |
1505 | @code{define-key-after} (@pxref{Modifying Menus}). | |
1506 | ||
969fe9b5 | 1507 | @menu |
a9f0a989 RS |
1508 | * Simple Menu Items:: A simple kind of menu key binding, |
1509 | limited in capabilities. | |
1510 | * Alias Menu Items:: Using command aliases in menu items. | |
1511 | * Extended Menu Items:: More powerful menu item definitions | |
1512 | let you specify keywords to enable | |
1513 | various features. | |
969fe9b5 RS |
1514 | @end menu |
1515 | ||
1516 | @node Simple Menu Items | |
1517 | @subsubsection Simple Menu Items | |
1518 | ||
1519 | The simpler and older way to define a menu keymap binding | |
1520 | looks like this: | |
87b2d5ff RS |
1521 | |
1522 | @example | |
969fe9b5 | 1523 | (@var{item-string} . @var{real-binding}) |
87b2d5ff RS |
1524 | @end example |
1525 | ||
a9f0a989 | 1526 | @noindent |
969fe9b5 RS |
1527 | The @sc{car}, @var{item-string}, is the string to be displayed in the |
1528 | menu. It should be short---preferably one to three words. It should | |
1529 | describe the action of the command it corresponds to. | |
87b2d5ff | 1530 | |
87b2d5ff RS |
1531 | You can also supply a second string, called the help string, as follows: |
1532 | ||
1533 | @example | |
969fe9b5 | 1534 | (@var{item-string} @var{help-string} . @var{real-binding}) |
87b2d5ff RS |
1535 | @end example |
1536 | ||
1537 | Currently Emacs does not actually use @var{help-string}; it knows only | |
1538 | how to ignore @var{help-string} in order to extract @var{real-binding}. | |
bfe721d1 KH |
1539 | In the future we may use @var{help-string} as extended documentation for |
1540 | the menu item, available on request. | |
87b2d5ff | 1541 | |
969fe9b5 | 1542 | As far as @code{define-key} is concerned, @var{item-string} and |
0521d6f5 RS |
1543 | @var{help-string} are part of the event's binding. However, |
1544 | @code{lookup-key} returns just @var{real-binding}, and only | |
1545 | @var{real-binding} is used for executing the key. | |
1546 | ||
969fe9b5 RS |
1547 | If @var{real-binding} is @code{nil}, then @var{item-string} appears in |
1548 | the menu but cannot be selected. | |
87b2d5ff RS |
1549 | |
1550 | If @var{real-binding} is a symbol and has a non-@code{nil} | |
1551 | @code{menu-enable} property, that property is an expression that | |
1552 | controls whether the menu item is enabled. Every time the keymap is | |
1553 | used to display a menu, Emacs evaluates the expression, and it enables | |
1554 | the menu item only if the expression's value is non-@code{nil}. When a | |
1555 | menu item is disabled, it is displayed in a ``fuzzy'' fashion, and | |
969fe9b5 | 1556 | cannot be selected. |
87b2d5ff | 1557 | |
bfe721d1 KH |
1558 | The menu bar does not recalculate which items are enabled every time you |
1559 | look at a menu. This is because the X toolkit requires the whole tree | |
1560 | of menus in advance. To force recalculation of the menu bar, call | |
1561 | @code{force-mode-line-update} (@pxref{Mode Line Format}). | |
1562 | ||
0521d6f5 RS |
1563 | You've probably noticed that menu items show the equivalent keyboard key |
1564 | sequence (if any) to invoke the same command. To save time on | |
1565 | recalculation, menu display caches this information in a sublist in the | |
1566 | binding, like this: | |
1567 | ||
1568 | @c This line is not too long--rms. | |
1569 | @example | |
969fe9b5 | 1570 | (@var{item-string} @r{[}@var{help-string}@r{]} (@var{key-binding-data}) . @var{real-binding}) |
0521d6f5 RS |
1571 | @end example |
1572 | ||
969fe9b5 | 1573 | @noindent |
0521d6f5 | 1574 | Don't put these sublists in the menu item yourself; menu display |
969fe9b5 RS |
1575 | calculates them automatically. Don't mention keyboard equivalents in |
1576 | the item strings themselves, since that is redundant. | |
0521d6f5 | 1577 | |
969fe9b5 RS |
1578 | @node Extended Menu Items |
1579 | @subsubsection Extended Menu Items | |
a9f0a989 | 1580 | @kindex menu-item |
969fe9b5 RS |
1581 | |
1582 | An extended-format menu item is a more flexible and also cleaner | |
1583 | alternative to the simple format. It consists of a list that starts | |
1584 | with the symbol @code{menu-item}. To define a non-selectable string, | |
1585 | the item looks like this: | |
1586 | ||
1587 | @example | |
1588 | (menu-item @var{item-name}) | |
1589 | @end example | |
1590 | ||
1591 | @noindent | |
1592 | where a string consisting of two or more dashes specifies a separator line. | |
1593 | ||
1594 | To define a real menu item which can be selected, the extended format | |
1595 | item looks like this: | |
1596 | ||
1597 | @example | |
1598 | (menu-item @var{item-name} @var{real-binding} | |
1599 | . @var{item-property-list}) | |
1600 | @end example | |
1601 | ||
1602 | @noindent | |
1603 | Here, @var{item-name} is an expression which evaluates to the menu item | |
1604 | string. Thus, the string need not be a constant. The third element, | |
1605 | @var{real-binding}, is the command to execute. The tail of the list, | |
1606 | @var{item-property-list}, has the form of a property list which contains | |
1607 | other information. Here is a table of the properties that are supported: | |
1608 | ||
1609 | @table @code | |
1610 | @item :enable FORM | |
1611 | The result of evaluating @var{form} determines whether the item is | |
1612 | enabled (non-@code{nil} means yes). | |
1613 | ||
1614 | @item :visible FORM | |
1615 | The result of evaluating @var{form} determines whether the item should | |
1616 | actually appear in the menu (non-@code{nil} means yes). If the item | |
1617 | does not appear, then the menu is displayed as if this item were | |
1618 | not defined at all. | |
1619 | ||
1620 | @item :help @var{help} | |
1621 | The value of this property, @var{help}, is the extra help string (not | |
a9f0a989 | 1622 | currently used by Emacs). |
969fe9b5 RS |
1623 | |
1624 | @item :button (@var{type} . @var{selected}) | |
1625 | This property provides a way to define radio buttons and toggle buttons. | |
1626 | The @sc{car}, @var{type}, says which: is should be @code{:toggle} or | |
1627 | @code{:radio}. The @sc{cdr}, @var{selected}, should be a form; the | |
1628 | result of evaluating it says whether this button is currently selected. | |
1629 | ||
a9f0a989 RS |
1630 | A @dfn{toggle} is a menu item which is labeled as either ``on'' or ``off'' |
1631 | according to the value of @var{selected}. The command itself should | |
1632 | toggle @var{selected}, setting it to @code{t} if it is @code{nil}, | |
1633 | and to @code{nil} if it is @code{t}. Here is how the menu item | |
1634 | to toggle the @code{debug-on-error} flag is defined: | |
1635 | ||
1636 | @example | |
1637 | (menu-item "Debug on Error" toggle-debug-on-error | |
1638 | :button (:toggle | |
1639 | . (and (boundp 'debug-on-error) | |
1640 | debug-on-error)) | |
1641 | @end example | |
1642 | ||
1643 | @noindent | |
1644 | This works because @code{toggle-debug-on-error} is defined as a command | |
1645 | which toggles the variable @code{debug-on-error}. | |
1646 | ||
1647 | @dfn{Radio buttons} are a group of menu items, in which at any time one | |
1648 | and only one is ``selected.'' There should be a variable whose value | |
1649 | says which one is selected at any time. The @var{selected} form for | |
1650 | each radio button in the group should check whether the variable has the | |
1651 | right value for selecting that button. Clicking on the button should | |
1652 | set the variable so that the button you clicked on becomes selected. | |
1653 | ||
1654 | @item :key-sequence @var{key-sequence} | |
1655 | This property specifies which key sequence is likely to be bound to the | |
1656 | same command invoked by this menu item. If you specify the right key | |
1657 | sequence, that makes preparing the menu for display run much faster. | |
1658 | ||
1659 | If you specify the wrong key sequence, it has no effect; before Emacs | |
1660 | displays @var{key-sequence} in the menu, it verifies that | |
1661 | @var{key-sequence} is really equivalent to this menu item. | |
1662 | ||
1663 | @item :key-sequence nil | |
1664 | This property indicates that there is normally no key binding which is | |
1665 | equivalent to this menu item. Using this property saves time in | |
1666 | preparing the menu for display, because Emacs does not need to search | |
1667 | the keymaps for a keyboard equivalent for this menu item. | |
1668 | ||
1669 | However, if the user has rebound this item's definition to a key | |
1670 | sequence, Emacs ignores the @code{:keys} property and finds the keyboard | |
1671 | equivalent anyway. | |
1672 | ||
1673 | @item :keys @var{string} | |
1674 | This property specifies that @var{string} is the string to display | |
1675 | as the keyboard equivalent for this menu item. You can use | |
1676 | the @samp{\\[...]} documentation construct in @var{string}. | |
1677 | ||
969fe9b5 RS |
1678 | @item :filter @var{filter-fn} |
1679 | This property provides a way to compute the menu item dynamically. | |
1680 | The property value @var{filter-fn} should be a function of one argument; | |
1681 | when it is called, its argument will be @var{real-binding}. The | |
1682 | function should return the binding to use instead. | |
1683 | @end table | |
1684 | ||
a9f0a989 RS |
1685 | @node Alias Menu Items |
1686 | @subsubsection Alias Menu Items | |
1687 | ||
1688 | Sometimes it is useful to make menu items that use the ``same'' | |
1689 | command but with different enable conditions. The best way to do this | |
1690 | in Emacs now is with extended menu items; before that feature existed, | |
1691 | it could be done by defining alias commands and using them in menu | |
1692 | items. Here's an example that makes two aliases for | |
1693 | @code{toggle-read-only} and gives them different enable conditions: | |
1694 | ||
1695 | @example | |
1696 | (defalias 'make-read-only 'toggle-read-only) | |
1697 | (put 'make-read-only 'menu-enable '(not buffer-read-only)) | |
1698 | (defalias 'make-writable 'toggle-read-only) | |
1699 | (put 'make-writable 'menu-enable 'buffer-read-only) | |
1700 | @end example | |
1701 | ||
1702 | When using aliases in menus, often it is useful to display the | |
1703 | equivalent key bindings for the ``real'' command name, not the aliases | |
1704 | (which typically don't have any key bindings except for the menu | |
1705 | itself). To request this, give the alias symbol a non-@code{nil} | |
1706 | @code{menu-alias} property. Thus, | |
1707 | ||
1708 | @example | |
1709 | (put 'make-read-only 'menu-alias t) | |
1710 | (put 'make-writable 'menu-alias t) | |
1711 | @end example | |
1712 | ||
1713 | @noindent | |
1714 | causes menu items for @code{make-read-only} and @code{make-writable} to | |
1715 | show the keyboard bindings for @code{toggle-read-only}. | |
1716 | ||
87b2d5ff RS |
1717 | @node Mouse Menus |
1718 | @subsection Menus and the Mouse | |
1719 | ||
969fe9b5 RS |
1720 | The usual way to make a menu keymap produce a menu is to make it the |
1721 | definition of a prefix key. (A Lisp program can explicitly pop up a | |
1722 | menu and receive the user's choice---see @ref{Pop-Up Menus}.) | |
87b2d5ff | 1723 | |
969fe9b5 | 1724 | If the prefix key ends with a mouse event, Emacs handles the menu keymap |
87b2d5ff RS |
1725 | by popping up a visible menu, so that the user can select a choice with |
1726 | the mouse. When the user clicks on a menu item, the event generated is | |
1727 | whatever character or symbol has the binding that brought about that | |
1728 | menu item. (A menu item may generate a series of events if the menu has | |
1729 | multiple levels or comes from the menu bar.) | |
1730 | ||
969fe9b5 | 1731 | It's often best to use a button-down event to trigger the menu. Then |
87b2d5ff RS |
1732 | the user can select a menu item by releasing the button. |
1733 | ||
969fe9b5 | 1734 | A single keymap can appear as multiple menu panes, if you explicitly |
87b2d5ff RS |
1735 | arrange for this. The way to do this is to make a keymap for each pane, |
1736 | then create a binding for each of those maps in the main keymap of the | |
1737 | menu. Give each of these bindings an item string that starts with | |
1738 | @samp{@@}. The rest of the item string becomes the name of the pane. | |
1739 | See the file @file{lisp/mouse.el} for an example of this. Any ordinary | |
1740 | bindings with @samp{@@}-less item strings are grouped into one pane, | |
1741 | which appears along with the other panes explicitly created for the | |
1742 | submaps. | |
1743 | ||
969fe9b5 | 1744 | X toolkit menus don't have panes; instead, they can have submenus. |
87b2d5ff RS |
1745 | Every nested keymap becomes a submenu, whether the item string starts |
1746 | with @samp{@@} or not. In a toolkit version of Emacs, the only thing | |
1747 | special about @samp{@@} at the beginning of an item string is that the | |
1748 | @samp{@@} doesn't appear in the menu item. | |
1749 | ||
969fe9b5 RS |
1750 | You can also produce multiple panes or submenus from separate keymaps. |
1751 | The full definition of a prefix key always comes from merging the | |
1752 | definitions supplied by the various active keymaps (minor mode, local, | |
1753 | and global). When more than one of these keymaps is a menu, each of | |
1754 | them makes a separate pane or panes (when Emacs does not use an | |
1755 | X-toolkit) or a separate submenu (when using an X-toolkit). | |
1756 | @xref{Active Keymaps}. | |
87b2d5ff RS |
1757 | |
1758 | @node Keyboard Menus | |
1759 | @subsection Menus and the Keyboard | |
1760 | ||
1761 | When a prefix key ending with a keyboard event (a character or function | |
1762 | key) has a definition that is a menu keymap, the user can use the | |
1763 | keyboard to choose a menu item. | |
1764 | ||
1765 | Emacs displays the menu alternatives (the item strings of the bindings) | |
1766 | in the echo area. If they don't all fit at once, the user can type | |
1767 | @key{SPC} to see the next line of alternatives. Successive uses of | |
1768 | @key{SPC} eventually get to the end of the menu and then cycle around to | |
1769 | the beginning. (The variable @code{menu-prompt-more-char} specifies | |
1770 | which character is used for this; @key{SPC} is the default.) | |
1771 | ||
1772 | When the user has found the desired alternative from the menu, he or she | |
1773 | should type the corresponding character---the one whose binding is that | |
1774 | alternative. | |
1775 | ||
bfe721d1 | 1776 | @ignore |
87b2d5ff RS |
1777 | In a menu intended for keyboard use, each menu item must clearly |
1778 | indicate what character to type. The best convention to use is to make | |
bfe721d1 KH |
1779 | the character the first letter of the item string---that is something |
1780 | users will understand without being told. We plan to change this; by | |
1781 | the time you read this manual, keyboard menus may explicitly name the | |
1782 | key for each alternative. | |
1783 | @end ignore | |
87b2d5ff RS |
1784 | |
1785 | This way of using menus in an Emacs-like editor was inspired by the | |
1786 | Hierarkey system. | |
73804d4b | 1787 | |
87b2d5ff RS |
1788 | @defvar menu-prompt-more-char |
1789 | This variable specifies the character to use to ask to see | |
1790 | the next line of a menu. Its initial value is 32, the code | |
1791 | for @key{SPC}. | |
1792 | @end defvar | |
73804d4b | 1793 | |
87b2d5ff RS |
1794 | @node Menu Example |
1795 | @subsection Menu Example | |
f9f59935 | 1796 | @cindex menu definition example |
73804d4b | 1797 | |
f9f59935 RS |
1798 | Here is a complete example of defining a menu keymap. It is the |
1799 | definition of the @samp{Print} submenu in the @samp{Tools} menu in the | |
a9f0a989 RS |
1800 | menu bar, and it uses the simple menu item format (@pxref{Simple Menu |
1801 | Items}). First we create the keymap, and give it a name: | |
73804d4b | 1802 | |
87b2d5ff | 1803 | @example |
f9f59935 | 1804 | (defvar menu-bar-print-menu (make-sparse-keymap "Print")) |
87b2d5ff | 1805 | @end example |
73804d4b | 1806 | |
969fe9b5 RS |
1807 | @noindent |
1808 | Next we define the menu items: | |
73804d4b | 1809 | |
f9f59935 RS |
1810 | @example |
1811 | (define-key menu-bar-print-menu [ps-print-region] | |
1812 | '("Postscript Print Region" . ps-print-region-with-faces)) | |
1813 | (define-key menu-bar-print-menu [ps-print-buffer] | |
1814 | '("Postscript Print Buffer" . ps-print-buffer-with-faces)) | |
1815 | (define-key menu-bar-print-menu [separator-ps-print] | |
1816 | '("--")) | |
1817 | (define-key menu-bar-print-menu [print-region] | |
1818 | '("Print Region" . print-region)) | |
1819 | (define-key menu-bar-print-menu [print-buffer] | |
1820 | '("Print Buffer" . print-buffer)) | |
1821 | @end example | |
1822 | ||
1823 | @noindent | |
1824 | Note the symbols which the bindings are ``made for''; these appear | |
1825 | inside square brackets, in the key sequence being defined. In some | |
1826 | cases, this symbol is the same as the command name; sometimes it is | |
1827 | different. These symbols are treated as ``function keys'', but they are | |
1828 | not real function keys on the keyboard. They do not affect the | |
1829 | functioning of the menu itself, but they are ``echoed'' in the echo area | |
1830 | when the user selects from the menu, and they appear in the output of | |
1831 | @code{where-is} and @code{apropos}. | |
1832 | ||
1833 | The binding whose definition is @code{("--")} is a separator line. | |
1834 | Like a real menu item, the separator has a key symbol, in this case | |
1835 | @code{separator-ps-print}. If one menu has two separators, they must | |
1836 | have two different key symbols. | |
1837 | ||
1838 | Here is code to define enable conditions for two of the commands in | |
1839 | the menu: | |
1840 | ||
1841 | @example | |
1842 | (put 'print-region 'menu-enable 'mark-active) | |
1843 | (put 'ps-print-region-with-faces 'menu-enable 'mark-active) | |
1844 | @end example | |
1845 | ||
1846 | Here is how we make this menu appear as an item in the parent menu: | |
1847 | ||
1848 | @example | |
1849 | (define-key menu-bar-tools-menu [print] | |
1850 | (cons "Print" menu-bar-print-menu)) | |
1851 | @end example | |
1852 | ||
1853 | @noindent | |
1854 | Note that this incorporates the submenu keymap, which is the value of | |
1855 | the variable @code{menu-bar-print-menu}, rather than the symbol | |
1856 | @code{menu-bar-print-menu} itself. Using that symbol in the parent menu | |
1857 | item would be meaningless because @code{menu-bar-print-menu} is not a | |
1858 | command. | |
1859 | ||
1860 | If you wanted to attach the same print menu to a mouse click, you | |
969fe9b5 | 1861 | can do it this way: |
f9f59935 RS |
1862 | |
1863 | @example | |
a9f0a989 RS |
1864 | (define-key global-map [C-S-down-mouse-1] |
1865 | menu-bar-print-menu) | |
1866 | @end example | |
1867 | ||
1868 | We could equally well use an extended menu item (@pxref{Extended Menu | |
1869 | Items}) for @code{print-region}, like this: | |
1870 | ||
1871 | @example | |
1872 | (define-key menu-bar-print-menu [print-region] | |
1873 | '(menu-item "Print Region" print-region | |
1874 | :enable (mark-active))) | |
1875 | @end example | |
1876 | ||
1877 | @noindent | |
1878 | With the extended menu item, the enable condition is specified | |
1879 | inside the menu item itself. If we wanted to make this | |
1880 | item disappear from the menu entirely when the mark is inactive, | |
1881 | we could do it this way: | |
1882 | ||
1883 | @example | |
1884 | (define-key menu-bar-print-menu [print-region] | |
1885 | '(menu-item "Print Region" print-region | |
1886 | :visible (mark-active))) | |
f9f59935 | 1887 | @end example |
73804d4b | 1888 | |
87b2d5ff RS |
1889 | @node Menu Bar |
1890 | @subsection The Menu Bar | |
1891 | @cindex menu bar | |
73804d4b | 1892 | |
87b2d5ff RS |
1893 | Most window systems allow each frame to have a @dfn{menu bar}---a |
1894 | permanently displayed menu stretching horizontally across the top of the | |
1895 | frame. The items of the menu bar are the subcommands of the fake | |
1896 | ``function key'' @code{menu-bar}, as defined by all the active keymaps. | |
73804d4b | 1897 | |
87b2d5ff RS |
1898 | To add an item to the menu bar, invent a fake ``function key'' of your |
1899 | own (let's call it @var{key}), and make a binding for the key sequence | |
1900 | @code{[menu-bar @var{key}]}. Most often, the binding is a menu keymap, | |
1901 | so that pressing a button on the menu bar item leads to another menu. | |
73804d4b | 1902 | |
87b2d5ff RS |
1903 | When more than one active keymap defines the same fake function key |
1904 | for the menu bar, the item appears just once. If the user clicks on | |
969fe9b5 | 1905 | that menu bar item, it brings up a single, combined menu containing |
87b2d5ff | 1906 | all the subcommands of that item---the global subcommands, the local |
969fe9b5 | 1907 | subcommands, and the minor mode subcommands. |
73804d4b | 1908 | |
22697dac KH |
1909 | The variable @code{overriding-local-map} is normally ignored when |
1910 | determining the menu bar contents. That is, the menu bar is computed | |
1911 | from the keymaps that would be active if @code{overriding-local-map} | |
1912 | were @code{nil}. @xref{Active Keymaps}. | |
1913 | ||
87b2d5ff RS |
1914 | In order for a frame to display a menu bar, its @code{menu-bar-lines} |
1915 | parameter must be greater than zero. Emacs uses just one line for the | |
1916 | menu bar itself; if you specify more than one line, the other lines | |
1917 | serve to separate the menu bar from the windows in the frame. We | |
969fe9b5 | 1918 | recommend 1 or 2 as the value of @code{menu-bar-lines}. @xref{Window Frame |
bfe721d1 | 1919 | Parameters}. |
73804d4b | 1920 | |
87b2d5ff | 1921 | Here's an example of setting up a menu bar item: |
73804d4b | 1922 | |
87b2d5ff | 1923 | @example |
73804d4b | 1924 | @group |
87b2d5ff RS |
1925 | (modify-frame-parameters (selected-frame) |
1926 | '((menu-bar-lines . 2))) | |
73804d4b | 1927 | @end group |
73804d4b | 1928 | |
73804d4b | 1929 | @group |
87b2d5ff RS |
1930 | ;; @r{Make a menu keymap (with a prompt string)} |
1931 | ;; @r{and make it the menu bar item's definition.} | |
1932 | (define-key global-map [menu-bar words] | |
1933 | (cons "Words" (make-sparse-keymap "Words"))) | |
73804d4b | 1934 | @end group |
87b2d5ff | 1935 | |
73804d4b | 1936 | @group |
969fe9b5 | 1937 | ;; @r{Define specific subcommands in this menu.} |
87b2d5ff RS |
1938 | (define-key global-map |
1939 | [menu-bar words forward] | |
1940 | '("Forward word" . forward-word)) | |
73804d4b | 1941 | @end group |
73804d4b | 1942 | @group |
87b2d5ff RS |
1943 | (define-key global-map |
1944 | [menu-bar words backward] | |
1945 | '("Backward word" . backward-word)) | |
73804d4b | 1946 | @end group |
87b2d5ff | 1947 | @end example |
73804d4b | 1948 | |
87b2d5ff RS |
1949 | A local keymap can cancel a menu bar item made by the global keymap by |
1950 | rebinding the same fake function key with @code{undefined} as the | |
1951 | binding. For example, this is how Dired suppresses the @samp{Edit} menu | |
1952 | bar item: | |
73804d4b | 1953 | |
87b2d5ff RS |
1954 | @example |
1955 | (define-key dired-mode-map [menu-bar edit] 'undefined) | |
1956 | @end example | |
73804d4b | 1957 | |
87b2d5ff RS |
1958 | @noindent |
1959 | @code{edit} is the fake function key used by the global map for the | |
1960 | @samp{Edit} menu bar item. The main reason to suppress a global | |
1961 | menu bar item is to regain space for mode-specific items. | |
73804d4b | 1962 | |
87b2d5ff RS |
1963 | @defvar menu-bar-final-items |
1964 | Normally the menu bar shows global items followed by items defined by the | |
1965 | local maps. | |
73804d4b | 1966 | |
87b2d5ff RS |
1967 | This variable holds a list of fake function keys for items to display at |
1968 | the end of the menu bar rather than in normal sequence. The default | |
969fe9b5 | 1969 | value is @code{(help-menu)}; thus, the @samp{Help} menu item normally appears |
87b2d5ff RS |
1970 | at the end of the menu bar, following local menu items. |
1971 | @end defvar | |
73804d4b | 1972 | |
bd98ada9 RS |
1973 | @defvar menu-bar-update-hook |
1974 | This normal hook is run whenever the user clicks on the menu bar, before | |
1975 | displaying a submenu. You can use it to update submenus whose contents | |
1976 | should vary. | |
1977 | @end defvar | |
1978 | ||
87b2d5ff RS |
1979 | @node Modifying Menus |
1980 | @subsection Modifying Menus | |
73804d4b | 1981 | |
87b2d5ff RS |
1982 | When you insert a new item in an existing menu, you probably want to |
1983 | put it in a particular place among the menu's existing items. If you | |
1984 | use @code{define-key} to add the item, it normally goes at the front of | |
f9f59935 | 1985 | the menu. To put it elsewhere in the menu, use @code{define-key-after}: |
73804d4b | 1986 | |
87b2d5ff RS |
1987 | @defun define-key-after map key binding after |
1988 | Define a binding in @var{map} for @var{key}, with value @var{binding}, | |
1989 | just like @code{define-key}, but position the binding in @var{map} after | |
f9f59935 RS |
1990 | the binding for the event @var{after}. The argument @var{key} should be |
1991 | of length one---a vector or string with just one element. But | |
969fe9b5 RS |
1992 | @var{after} should be a single event type---a symbol or a character, not |
1993 | a sequence. The new binding goes after the binding for @var{after}. If | |
1994 | @var{after} is @code{t}, then the new binding goes last, at the end of | |
1995 | the keymap. | |
b2955417 | 1996 | |
969fe9b5 | 1997 | Here is an example: |
73804d4b | 1998 | |
87b2d5ff RS |
1999 | @example |
2000 | (define-key-after my-menu [drink] | |
2001 | '("Drink" . drink-command) 'eat) | |
2002 | @end example | |
73804d4b | 2003 | |
87b2d5ff | 2004 | @noindent |
969fe9b5 RS |
2005 | makes a binding for the fake function key @key{DRINK} and puts it |
2006 | right after the binding for @key{EAT}. | |
f9f59935 | 2007 | |
87b2d5ff RS |
2008 | Here is how to insert an item called @samp{Work} in the @samp{Signals} |
2009 | menu of Shell mode, after the item @code{break}: | |
73804d4b | 2010 | |
87b2d5ff RS |
2011 | @example |
2012 | (define-key-after | |
2013 | (lookup-key shell-mode-map [menu-bar signals]) | |
2014 | [work] '("Work" . work-command) 'break) | |
2015 | @end example | |
87b2d5ff | 2016 | @end defun |