| 1 | @c -*-texinfo-*- |
| 2 | @c This is part of the GNU Emacs Lisp Reference Manual. |
| 3 | @c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1998, 1999, 2000 |
| 4 | @c Free Software Foundation, Inc. |
| 5 | @c See the file elisp.texi for copying conditions. |
| 6 | @setfilename ../info/keymaps |
| 7 | @node Keymaps, Modes, Command Loop, Top |
| 8 | @chapter Keymaps |
| 9 | @cindex keymap |
| 10 | |
| 11 | The bindings between input events and commands are recorded in data |
| 12 | structures called @dfn{keymaps}. Each binding in a keymap associates |
| 13 | (or @dfn{binds}) an individual event type either to another keymap or to |
| 14 | a command. When an event type is bound to a keymap, that keymap is used |
| 15 | to look up the next input event; this continues until a command is |
| 16 | found. The whole process is called @dfn{key lookup}. |
| 17 | |
| 18 | @menu |
| 19 | * Keymap Terminology:: Definitions of terms pertaining to keymaps. |
| 20 | * Format of Keymaps:: What a keymap looks like as a Lisp object. |
| 21 | * Creating Keymaps:: Functions to create and copy keymaps. |
| 22 | * Inheritance and Keymaps:: How one keymap can inherit the bindings |
| 23 | of another keymap. |
| 24 | * Prefix Keys:: Defining a key with a keymap as its definition. |
| 25 | * Active Keymaps:: Each buffer has a local keymap |
| 26 | to override the standard (global) bindings. |
| 27 | A minor mode can also override them. |
| 28 | * Key Lookup:: How extracting elements from keymaps works. |
| 29 | * Functions for Key Lookup:: How to request key lookup. |
| 30 | * Changing Key Bindings:: Redefining a key in a keymap. |
| 31 | * Key Binding Commands:: Interactive interfaces for redefining keys. |
| 32 | * Scanning Keymaps:: Looking through all keymaps, for printing help. |
| 33 | * Menu Keymaps:: Defining a menu as a keymap. |
| 34 | @end menu |
| 35 | |
| 36 | @node Keymap Terminology |
| 37 | @section Keymap Terminology |
| 38 | @cindex key |
| 39 | @cindex keystroke |
| 40 | @cindex key binding |
| 41 | @cindex binding of a key |
| 42 | @cindex complete key |
| 43 | @cindex undefined key |
| 44 | |
| 45 | A @dfn{keymap} is a table mapping event types to definitions (which |
| 46 | can be any Lisp objects, though only certain types are meaningful for |
| 47 | execution by the command loop). Given an event (or an event type) and a |
| 48 | keymap, Emacs can get the event's definition. Events include |
| 49 | characters, function keys, and mouse actions (@pxref{Input Events}). |
| 50 | |
| 51 | A sequence of input events that form a unit is called a |
| 52 | @dfn{key sequence}, or @dfn{key} for short. A sequence of one event |
| 53 | is always a key sequence, and so are some multi-event sequences. |
| 54 | |
| 55 | A keymap determines a binding or definition for any key sequence. If |
| 56 | the key sequence is a single event, its binding is the definition of the |
| 57 | event in the keymap. The binding of a key sequence of more than one |
| 58 | event is found by an iterative process: the binding of the first event |
| 59 | is found, and must be a keymap; then the second event's binding is found |
| 60 | in that keymap, and so on until all the events in the key sequence are |
| 61 | used up. |
| 62 | |
| 63 | If the binding of a key sequence is a keymap, we call the key sequence |
| 64 | a @dfn{prefix key}. Otherwise, we call it a @dfn{complete key} (because |
| 65 | no more events can be added to it). If the binding is @code{nil}, |
| 66 | we call the key @dfn{undefined}. Examples of prefix keys are @kbd{C-c}, |
| 67 | @kbd{C-x}, and @kbd{C-x 4}. Examples of defined complete keys are |
| 68 | @kbd{X}, @key{RET}, and @kbd{C-x 4 C-f}. Examples of undefined complete |
| 69 | keys are @kbd{C-x C-g}, and @kbd{C-c 3}. @xref{Prefix Keys}, for more |
| 70 | details. |
| 71 | |
| 72 | The rule for finding the binding of a key sequence assumes that the |
| 73 | intermediate bindings (found for the events before the last) are all |
| 74 | keymaps; if this is not so, the sequence of events does not form a |
| 75 | unit---it is not really one key sequence. In other words, removing one |
| 76 | or more events from the end of any valid key sequence must always yield |
| 77 | a prefix key. For example, @kbd{C-f C-n} is not a key sequence; |
| 78 | @kbd{C-f} is not a prefix key, so a longer sequence starting with |
| 79 | @kbd{C-f} cannot be a key sequence. |
| 80 | |
| 81 | The set of possible multi-event key sequences depends on the bindings |
| 82 | for prefix keys; therefore, it can be different for different keymaps, |
| 83 | and can change when bindings are changed. However, a one-event sequence |
| 84 | is always a key sequence, because it does not depend on any prefix keys |
| 85 | for its well-formedness. |
| 86 | |
| 87 | At any time, several primary keymaps are @dfn{active}---that is, in |
| 88 | use for finding key bindings. These are the @dfn{global map}, which is |
| 89 | shared by all buffers; the @dfn{local keymap}, which is usually |
| 90 | associated with a specific major mode; and zero or more @dfn{minor mode |
| 91 | keymaps}, which belong to currently enabled minor modes. (Not all minor |
| 92 | modes have keymaps.) The local keymap bindings shadow (i.e., take |
| 93 | precedence over) the corresponding global bindings. The minor mode |
| 94 | keymaps shadow both local and global keymaps. @xref{Active Keymaps}, |
| 95 | for details. |
| 96 | |
| 97 | @node Format of Keymaps |
| 98 | @section Format of Keymaps |
| 99 | @cindex format of keymaps |
| 100 | @cindex keymap format |
| 101 | @cindex full keymap |
| 102 | @cindex sparse keymap |
| 103 | |
| 104 | A keymap is a list whose @sc{car} is the symbol @code{keymap}. The |
| 105 | remaining elements of the list define the key bindings of the keymap. |
| 106 | Use the function @code{keymapp} (see below) to test whether an object is |
| 107 | a keymap. |
| 108 | |
| 109 | Several kinds of elements may appear in a keymap, after the symbol |
| 110 | @code{keymap} that begins it: |
| 111 | |
| 112 | @table @code |
| 113 | @item (@var{type} .@: @var{binding}) |
| 114 | This specifies one binding, for events of type @var{type}. Each |
| 115 | ordinary binding applies to events of a particular @dfn{event type}, |
| 116 | which is always a character or a symbol. @xref{Classifying Events}. |
| 117 | |
| 118 | @item (t .@: @var{binding}) |
| 119 | @cindex default key binding |
| 120 | This specifies a @dfn{default key binding}; any event not bound by other |
| 121 | elements of the keymap is given @var{binding} as its binding. Default |
| 122 | bindings allow a keymap to bind all possible event types without having |
| 123 | to enumerate all of them. A keymap that has a default binding |
| 124 | completely masks any lower-precedence keymap. |
| 125 | |
| 126 | @item @var{vector} |
| 127 | If an element of a keymap is a vector, the vector counts as bindings for |
| 128 | all the @sc{ascii} characters, codes 0 through 127; vector element |
| 129 | @var{n} is the binding for the character with code @var{n}. This is a |
| 130 | compact way to record lots of bindings. A keymap with such a vector is |
| 131 | called a @dfn{full keymap}. Other keymaps are called @dfn{sparse |
| 132 | keymaps}. |
| 133 | |
| 134 | When a keymap contains a vector, it always defines a binding for each |
| 135 | @sc{ascii} character, even if the vector contains @code{nil} for that |
| 136 | character. Such a binding of @code{nil} overrides any default key |
| 137 | binding in the keymap, for @sc{ascii} characters. However, default |
| 138 | bindings are still meaningful for events other than @sc{ascii} |
| 139 | characters. A binding of @code{nil} does @emph{not} override |
| 140 | lower-precedence keymaps; thus, if the local map gives a binding of |
| 141 | @code{nil}, Emacs uses the binding from the global map. |
| 142 | |
| 143 | @item @var{string} |
| 144 | @cindex keymap prompt string |
| 145 | @cindex overall prompt string |
| 146 | @cindex prompt string of keymap |
| 147 | Aside from bindings, a keymap can also have a string as an element. |
| 148 | This is called the @dfn{overall prompt string} and makes it possible to |
| 149 | use the keymap as a menu. @xref{Defining Menus}. |
| 150 | @end table |
| 151 | |
| 152 | @cindex meta characters lookup |
| 153 | Keymaps do not directly record bindings for the meta characters. |
| 154 | Instead, meta characters are regarded for |
| 155 | purposes of key lookup as sequences of two characters, the first of |
| 156 | which is @key{ESC} (or whatever is currently the value of |
| 157 | @code{meta-prefix-char}). Thus, the key @kbd{M-a} is really represented |
| 158 | as @kbd{@key{ESC} a}, and its global binding is found at the slot for |
| 159 | @kbd{a} in @code{esc-map} (@pxref{Prefix Keys}). |
| 160 | |
| 161 | Here as an example is the local keymap for Lisp mode, a sparse |
| 162 | keymap. It defines bindings for @key{DEL} and @key{TAB}, plus @kbd{C-c |
| 163 | C-l}, @kbd{M-C-q}, and @kbd{M-C-x}. |
| 164 | |
| 165 | @example |
| 166 | @group |
| 167 | lisp-mode-map |
| 168 | @result{} |
| 169 | @end group |
| 170 | @group |
| 171 | (keymap |
| 172 | ;; @key{TAB} |
| 173 | (9 . lisp-indent-line) |
| 174 | @end group |
| 175 | @group |
| 176 | ;; @key{DEL} |
| 177 | (127 . backward-delete-char-untabify) |
| 178 | @end group |
| 179 | @group |
| 180 | (3 keymap |
| 181 | ;; @kbd{C-c C-l} |
| 182 | (12 . run-lisp)) |
| 183 | @end group |
| 184 | @group |
| 185 | (27 keymap |
| 186 | ;; @r{@kbd{M-C-q}, treated as @kbd{@key{ESC} C-q}} |
| 187 | (17 . indent-sexp) |
| 188 | ;; @r{@kbd{M-C-x}, treated as @kbd{@key{ESC} C-x}} |
| 189 | (24 . lisp-send-defun))) |
| 190 | @end group |
| 191 | @end example |
| 192 | |
| 193 | @defun keymapp object |
| 194 | This function returns @code{t} if @var{object} is a keymap, @code{nil} |
| 195 | otherwise. More precisely, this function tests for a list whose |
| 196 | @sc{car} is @code{keymap}. |
| 197 | |
| 198 | @example |
| 199 | @group |
| 200 | (keymapp '(keymap)) |
| 201 | @result{} t |
| 202 | @end group |
| 203 | @group |
| 204 | (keymapp (current-global-map)) |
| 205 | @result{} t |
| 206 | @end group |
| 207 | @end example |
| 208 | @end defun |
| 209 | |
| 210 | @node Creating Keymaps |
| 211 | @section Creating Keymaps |
| 212 | @cindex creating keymaps |
| 213 | |
| 214 | Here we describe the functions for creating keymaps. |
| 215 | |
| 216 | @c ??? This should come after make-sparse-keymap |
| 217 | @defun make-keymap &optional prompt |
| 218 | This function creates and returns a new full keymap (i.e., one |
| 219 | containing a vector of length 128 for defining all the @sc{ascii} |
| 220 | characters). The new keymap initially binds all @sc{ascii} characters |
| 221 | to @code{nil}, and does not bind any other kind of event. |
| 222 | |
| 223 | @example |
| 224 | @group |
| 225 | (make-keymap) |
| 226 | @result{} (keymap [nil nil nil @dots{} nil nil]) |
| 227 | @end group |
| 228 | @end example |
| 229 | |
| 230 | If you specify @var{prompt}, that becomes the overall prompt string for |
| 231 | the keymap. The prompt string should be provided for menu keymaps |
| 232 | (@pxref{Defining Menus}). |
| 233 | @end defun |
| 234 | |
| 235 | @defun make-sparse-keymap &optional prompt |
| 236 | This function creates and returns a new sparse keymap with no entries. |
| 237 | The new keymap does not bind any events. The argument @var{prompt} |
| 238 | specifies a prompt string, as in @code{make-keymap}. |
| 239 | |
| 240 | @example |
| 241 | @group |
| 242 | (make-sparse-keymap) |
| 243 | @result{} (keymap) |
| 244 | @end group |
| 245 | @end example |
| 246 | @end defun |
| 247 | |
| 248 | @defun copy-keymap keymap |
| 249 | This function returns a copy of @var{keymap}. Any keymaps that |
| 250 | appear directly as bindings in @var{keymap} are also copied recursively, |
| 251 | and so on to any number of levels. However, recursive copying does not |
| 252 | take place when the definition of a character is a symbol whose function |
| 253 | definition is a keymap; the same symbol appears in the new copy. |
| 254 | @c Emacs 19 feature |
| 255 | |
| 256 | @example |
| 257 | @group |
| 258 | (setq map (copy-keymap (current-local-map))) |
| 259 | @result{} (keymap |
| 260 | @end group |
| 261 | @group |
| 262 | ;; @r{(This implements meta characters.)} |
| 263 | (27 keymap |
| 264 | (83 . center-paragraph) |
| 265 | (115 . center-line)) |
| 266 | (9 . tab-to-tab-stop)) |
| 267 | @end group |
| 268 | |
| 269 | @group |
| 270 | (eq map (current-local-map)) |
| 271 | @result{} nil |
| 272 | @end group |
| 273 | @group |
| 274 | (equal map (current-local-map)) |
| 275 | @result{} t |
| 276 | @end group |
| 277 | @end example |
| 278 | @end defun |
| 279 | |
| 280 | @node Inheritance and Keymaps |
| 281 | @section Inheritance and Keymaps |
| 282 | @cindex keymap inheritance |
| 283 | @cindex inheriting a keymap's bindings |
| 284 | |
| 285 | A keymap can inherit the bindings of another keymap, which we call the |
| 286 | @dfn{parent keymap}. Such a keymap looks like this: |
| 287 | |
| 288 | @example |
| 289 | (keymap @var{bindings}@dots{} . @var{parent-keymap}) |
| 290 | @end example |
| 291 | |
| 292 | @noindent |
| 293 | The effect is that this keymap inherits all the bindings of |
| 294 | @var{parent-keymap}, whatever they may be at the time a key is looked up, |
| 295 | but can add to them or override them with @var{bindings}. |
| 296 | |
| 297 | If you change the bindings in @var{parent-keymap} using @code{define-key} |
| 298 | or other key-binding functions, these changes are visible in the |
| 299 | inheriting keymap unless shadowed by @var{bindings}. The converse is |
| 300 | not true: if you use @code{define-key} to change the inheriting keymap, |
| 301 | that affects @var{bindings}, but has no effect on @var{parent-keymap}. |
| 302 | |
| 303 | The proper way to construct a keymap with a parent is to use |
| 304 | @code{set-keymap-parent}; if you have code that directly constructs a |
| 305 | keymap with a parent, please convert the program to use |
| 306 | @code{set-keymap-parent} instead. |
| 307 | |
| 308 | @defun keymap-parent keymap |
| 309 | This returns the parent keymap of @var{keymap}. If @var{keymap} |
| 310 | has no parent, @code{keymap-parent} returns @code{nil}. |
| 311 | @end defun |
| 312 | |
| 313 | @defun set-keymap-parent keymap parent |
| 314 | This sets the parent keymap of @var{keymap} to @var{parent}, and returns |
| 315 | @var{parent}. If @var{parent} is @code{nil}, this function gives |
| 316 | @var{keymap} no parent at all. |
| 317 | |
| 318 | If @var{keymap} has submaps (bindings for prefix keys), they too receive |
| 319 | new parent keymaps that reflect what @var{parent} specifies for those |
| 320 | prefix keys. |
| 321 | @end defun |
| 322 | |
| 323 | Here is an example showing how to make a keymap that inherits |
| 324 | from @code{text-mode-map}: |
| 325 | |
| 326 | @example |
| 327 | (let ((map (make-sparse-keymap))) |
| 328 | (set-keymap-parent map text-mode-map) |
| 329 | map) |
| 330 | @end example |
| 331 | |
| 332 | @node Prefix Keys |
| 333 | @section Prefix Keys |
| 334 | @cindex prefix key |
| 335 | |
| 336 | A @dfn{prefix key} is a key sequence whose binding is a keymap. The |
| 337 | keymap defines what to do with key sequences that extend the prefix key. |
| 338 | For example, @kbd{C-x} is a prefix key, and it uses a keymap that is |
| 339 | also stored in the variable @code{ctl-x-map}. This keymap defines |
| 340 | bindings for key sequences starting with @kbd{C-x}. |
| 341 | |
| 342 | Some of the standard Emacs prefix keys use keymaps that are |
| 343 | also found in Lisp variables: |
| 344 | |
| 345 | @itemize @bullet |
| 346 | @item |
| 347 | @vindex esc-map |
| 348 | @findex ESC-prefix |
| 349 | @code{esc-map} is the global keymap for the @key{ESC} prefix key. Thus, |
| 350 | the global definitions of all meta characters are actually found here. |
| 351 | This map is also the function definition of @code{ESC-prefix}. |
| 352 | |
| 353 | @item |
| 354 | @cindex @kbd{C-h} |
| 355 | @code{help-map} is the global keymap for the @kbd{C-h} prefix key. |
| 356 | |
| 357 | @item |
| 358 | @cindex @kbd{C-c} |
| 359 | @vindex mode-specific-map |
| 360 | @code{mode-specific-map} is the global keymap for the prefix key |
| 361 | @kbd{C-c}. This map is actually global, not mode-specific, but its name |
| 362 | provides useful information about @kbd{C-c} in the output of @kbd{C-h b} |
| 363 | (@code{display-bindings}), since the main use of this prefix key is for |
| 364 | mode-specific bindings. |
| 365 | |
| 366 | @item |
| 367 | @cindex @kbd{C-x} |
| 368 | @vindex ctl-x-map |
| 369 | @findex Control-X-prefix |
| 370 | @code{ctl-x-map} is the global keymap used for the @kbd{C-x} prefix key. |
| 371 | This map is found via the function cell of the symbol |
| 372 | @code{Control-X-prefix}. |
| 373 | |
| 374 | @item |
| 375 | @cindex @kbd{C-x @key{RET}} |
| 376 | @vindex mule-keymap |
| 377 | @code{mule-keymap} is the global keymap used for the @kbd{C-x @key{RET}} |
| 378 | prefix key. |
| 379 | |
| 380 | @item |
| 381 | @cindex @kbd{C-x 4} |
| 382 | @vindex ctl-x-4-map |
| 383 | @code{ctl-x-4-map} is the global keymap used for the @kbd{C-x 4} prefix |
| 384 | key. |
| 385 | |
| 386 | @c Emacs 19 feature |
| 387 | @item |
| 388 | @cindex @kbd{C-x 5} |
| 389 | @vindex ctl-x-5-map |
| 390 | @code{ctl-x-5-map} is the global keymap used for the @kbd{C-x 5} prefix |
| 391 | key. |
| 392 | |
| 393 | @c Emacs 19 feature |
| 394 | @item |
| 395 | @cindex @kbd{C-x 6} |
| 396 | @vindex 2C-mode-map |
| 397 | @code{2C-mode-map} is the global keymap used for the @kbd{C-x 6} prefix |
| 398 | key. |
| 399 | |
| 400 | @item |
| 401 | @cindex @kbd{C-x v} |
| 402 | @vindex vc-prefix-map |
| 403 | @code{vc-prefix-map} is the global keymap used for the @kbd{C-x v} prefix |
| 404 | key. |
| 405 | |
| 406 | @item |
| 407 | @cindex @kbd{M-g} |
| 408 | @vindex facemenu-keymap |
| 409 | @code{facemenu-keymap} is the global keymap used for the @kbd{M-g} |
| 410 | prefix key. |
| 411 | |
| 412 | @c Emacs 19 feature |
| 413 | @item |
| 414 | The other Emacs prefix keys are @kbd{C-x @@}, @kbd{C-x a i}, @kbd{C-x |
| 415 | @key{ESC}} and @kbd{@key{ESC} @key{ESC}}. They use keymaps that have no |
| 416 | special names. |
| 417 | @end itemize |
| 418 | |
| 419 | The keymap binding of a prefix key is used for looking up the event |
| 420 | that follows the prefix key. (It may instead be a symbol whose function |
| 421 | definition is a keymap. The effect is the same, but the symbol serves |
| 422 | as a name for the prefix key.) Thus, the binding of @kbd{C-x} is the |
| 423 | symbol @code{Control-X-prefix}, whose function cell holds the keymap |
| 424 | for @kbd{C-x} commands. (The same keymap is also the value of |
| 425 | @code{ctl-x-map}.) |
| 426 | |
| 427 | Prefix key definitions can appear in any active keymap. The |
| 428 | definitions of @kbd{C-c}, @kbd{C-x}, @kbd{C-h} and @key{ESC} as prefix |
| 429 | keys appear in the global map, so these prefix keys are always |
| 430 | available. Major and minor modes can redefine a key as a prefix by |
| 431 | putting a prefix key definition for it in the local map or the minor |
| 432 | mode's map. @xref{Active Keymaps}. |
| 433 | |
| 434 | If a key is defined as a prefix in more than one active map, then its |
| 435 | various definitions are in effect merged: the commands defined in the |
| 436 | minor mode keymaps come first, followed by those in the local map's |
| 437 | prefix definition, and then by those from the global map. |
| 438 | |
| 439 | In the following example, we make @kbd{C-p} a prefix key in the local |
| 440 | keymap, in such a way that @kbd{C-p} is identical to @kbd{C-x}. Then |
| 441 | the binding for @kbd{C-p C-f} is the function @code{find-file}, just |
| 442 | like @kbd{C-x C-f}. The key sequence @kbd{C-p 6} is not found in any |
| 443 | active keymap. |
| 444 | |
| 445 | @example |
| 446 | @group |
| 447 | (use-local-map (make-sparse-keymap)) |
| 448 | @result{} nil |
| 449 | @end group |
| 450 | @group |
| 451 | (local-set-key "\C-p" ctl-x-map) |
| 452 | @result{} nil |
| 453 | @end group |
| 454 | @group |
| 455 | (key-binding "\C-p\C-f") |
| 456 | @result{} find-file |
| 457 | @end group |
| 458 | |
| 459 | @group |
| 460 | (key-binding "\C-p6") |
| 461 | @result{} nil |
| 462 | @end group |
| 463 | @end example |
| 464 | |
| 465 | @defun define-prefix-command symbol &optional mapvar prompt |
| 466 | @cindex prefix command |
| 467 | This function prepares @var{symbol} for use as a prefix key's binding: |
| 468 | it creates a sparse keymap and stores it as @var{symbol}'s function |
| 469 | definition. Subsequently binding a key sequence to @var{symbol} will |
| 470 | make that key sequence into a prefix key. The return value is @code{symbol}. |
| 471 | |
| 472 | This function also sets @var{symbol} as a variable, with the keymap as |
| 473 | its value. But if @var{mapvar} is non-@code{nil}, it sets @var{mapvar} |
| 474 | as a variable instead. |
| 475 | |
| 476 | If @var{prompt} is non-@code{nil}, that becomes the overall prompt |
| 477 | string for the keymap. The prompt string should be given for menu keymaps |
| 478 | (@pxref{Defining Menus}). |
| 479 | @end defun |
| 480 | |
| 481 | @node Active Keymaps |
| 482 | @section Active Keymaps |
| 483 | @cindex active keymap |
| 484 | @cindex global keymap |
| 485 | @cindex local keymap |
| 486 | |
| 487 | Emacs normally contains many keymaps; at any given time, just a few of |
| 488 | them are @dfn{active} in that they participate in the interpretation |
| 489 | of user input. These are the global keymap, the current buffer's |
| 490 | local keymap, and the keymaps of any enabled minor modes. |
| 491 | |
| 492 | The @dfn{global keymap} holds the bindings of keys that are defined |
| 493 | regardless of the current buffer, such as @kbd{C-f}. The variable |
| 494 | @code{global-map} holds this keymap, which is always active. |
| 495 | |
| 496 | Each buffer may have another keymap, its @dfn{local keymap}, which may |
| 497 | contain new or overriding definitions for keys. The current buffer's |
| 498 | local keymap is always active except when @code{overriding-local-map} |
| 499 | overrides it. Text properties can specify an alternative local map for |
| 500 | certain parts of the buffer; see @ref{Special Properties}. |
| 501 | |
| 502 | Each minor mode can have a keymap; if it does, the keymap is active |
| 503 | when the minor mode is enabled. |
| 504 | |
| 505 | The variable @code{overriding-local-map}, if non-@code{nil}, specifies |
| 506 | another local keymap that overrides the buffer's local map and all the |
| 507 | minor mode keymaps. |
| 508 | |
| 509 | All the active keymaps are used together to determine what command to |
| 510 | execute when a key is entered. Emacs searches these maps one by one, in |
| 511 | order of decreasing precedence, until it finds a binding in one of the |
| 512 | maps. The procedure for searching a single keymap is called @dfn{key |
| 513 | lookup}; see @ref{Key Lookup}. |
| 514 | |
| 515 | Normally, Emacs first searches for the key in the minor mode maps, in |
| 516 | the order specified by @code{minor-mode-map-alist}; if they do not |
| 517 | supply a binding for the key, Emacs searches the local map; if that too |
| 518 | has no binding, Emacs then searches the global map. However, if |
| 519 | @code{overriding-local-map} is non-@code{nil}, Emacs searches that map |
| 520 | first, before the global map. |
| 521 | |
| 522 | @cindex major mode keymap |
| 523 | Since every buffer that uses the same major mode normally uses the |
| 524 | same local keymap, you can think of the keymap as local to the mode. A |
| 525 | change to the local keymap of a buffer (using @code{local-set-key}, for |
| 526 | example) is seen also in the other buffers that share that keymap. |
| 527 | |
| 528 | The local keymaps that are used for Lisp mode and some other major |
| 529 | modes exist even if they have not yet been used. These local maps are |
| 530 | the values of variables such as @code{lisp-mode-map}. For most major |
| 531 | modes, which are less frequently used, the local keymap is constructed |
| 532 | only when the mode is used for the first time in a session. |
| 533 | |
| 534 | The minibuffer has local keymaps, too; they contain various completion |
| 535 | and exit commands. @xref{Intro to Minibuffers}. |
| 536 | |
| 537 | Emacs has other keymaps that are used in a different way---translating |
| 538 | events within @code{read-key-sequence}. @xref{Translating Input}. |
| 539 | |
| 540 | @xref{Standard Keymaps}, for a list of standard keymaps. |
| 541 | |
| 542 | @defvar global-map |
| 543 | This variable contains the default global keymap that maps Emacs |
| 544 | keyboard input to commands. The global keymap is normally this keymap. |
| 545 | The default global keymap is a full keymap that binds |
| 546 | @code{self-insert-command} to all of the printing characters. |
| 547 | |
| 548 | It is normal practice to change the bindings in the global map, but you |
| 549 | should not assign this variable any value other than the keymap it starts |
| 550 | out with. |
| 551 | @end defvar |
| 552 | |
| 553 | @defun current-global-map |
| 554 | This function returns the current global keymap. This is the |
| 555 | same as the value of @code{global-map} unless you change one or the |
| 556 | other. |
| 557 | |
| 558 | @example |
| 559 | @group |
| 560 | (current-global-map) |
| 561 | @result{} (keymap [set-mark-command beginning-of-line @dots{} |
| 562 | delete-backward-char]) |
| 563 | @end group |
| 564 | @end example |
| 565 | @end defun |
| 566 | |
| 567 | @defun current-local-map |
| 568 | This function returns the current buffer's local keymap, or @code{nil} |
| 569 | if it has none. In the following example, the keymap for the |
| 570 | @samp{*scratch*} buffer (using Lisp Interaction mode) is a sparse keymap |
| 571 | in which the entry for @key{ESC}, @sc{ascii} code 27, is another sparse |
| 572 | keymap. |
| 573 | |
| 574 | @example |
| 575 | @group |
| 576 | (current-local-map) |
| 577 | @result{} (keymap |
| 578 | (10 . eval-print-last-sexp) |
| 579 | (9 . lisp-indent-line) |
| 580 | (127 . backward-delete-char-untabify) |
| 581 | @end group |
| 582 | @group |
| 583 | (27 keymap |
| 584 | (24 . eval-defun) |
| 585 | (17 . indent-sexp))) |
| 586 | @end group |
| 587 | @end example |
| 588 | @end defun |
| 589 | |
| 590 | @defun current-minor-mode-maps |
| 591 | This function returns a list of the keymaps of currently enabled minor modes. |
| 592 | @end defun |
| 593 | |
| 594 | @defun use-global-map keymap |
| 595 | This function makes @var{keymap} the new current global keymap. It |
| 596 | returns @code{nil}. |
| 597 | |
| 598 | It is very unusual to change the global keymap. |
| 599 | @end defun |
| 600 | |
| 601 | @defun use-local-map keymap |
| 602 | This function makes @var{keymap} the new local keymap of the current |
| 603 | buffer. If @var{keymap} is @code{nil}, then the buffer has no local |
| 604 | keymap. @code{use-local-map} returns @code{nil}. Most major mode |
| 605 | commands use this function. |
| 606 | @end defun |
| 607 | |
| 608 | @c Emacs 19 feature |
| 609 | @defvar minor-mode-map-alist |
| 610 | This variable is an alist describing keymaps that may or may not be |
| 611 | active according to the values of certain variables. Its elements look |
| 612 | like this: |
| 613 | |
| 614 | @example |
| 615 | (@var{variable} . @var{keymap}) |
| 616 | @end example |
| 617 | |
| 618 | The keymap @var{keymap} is active whenever @var{variable} has a |
| 619 | non-@code{nil} value. Typically @var{variable} is the variable that |
| 620 | enables or disables a minor mode. @xref{Keymaps and Minor Modes}. |
| 621 | |
| 622 | Note that elements of @code{minor-mode-map-alist} do not have the same |
| 623 | structure as elements of @code{minor-mode-alist}. The map must be the |
| 624 | @sc{cdr} of the element; a list with the map as the second element will |
| 625 | not do. The @sc{cdr} can be either a keymap (a list) or a symbol whose |
| 626 | function definition is a keymap. |
| 627 | |
| 628 | When more than one minor mode keymap is active, their order of priority |
| 629 | is the order of @code{minor-mode-map-alist}. But you should design |
| 630 | minor modes so that they don't interfere with each other. If you do |
| 631 | this properly, the order will not matter. |
| 632 | |
| 633 | See @ref{Keymaps and Minor Modes}, for more information about minor |
| 634 | modes. See also @code{minor-mode-key-binding} (@pxref{Functions for Key |
| 635 | Lookup}). |
| 636 | @end defvar |
| 637 | |
| 638 | @defvar minor-mode-overriding-map-alist |
| 639 | This variable allows major modes to override the key bindings for |
| 640 | particular minor modes. The elements of this alist look like the |
| 641 | elements of @code{minor-mode-map-alist}: @code{(@var{variable} |
| 642 | . @var{keymap})}. |
| 643 | |
| 644 | If a variable appears as an element of |
| 645 | @code{minor-mode-overriding-map-alist}, the map specified by that |
| 646 | element totally replaces any map specified for the same variable in |
| 647 | @code{minor-mode-map-alist}. |
| 648 | |
| 649 | @code{minor-mode-overriding-map-alist} is automatically buffer-local in |
| 650 | all buffers. |
| 651 | @end defvar |
| 652 | |
| 653 | @defvar overriding-local-map |
| 654 | If non-@code{nil}, this variable holds a keymap to use instead of the |
| 655 | buffer's local keymap and instead of all the minor mode keymaps. This |
| 656 | keymap, if any, overrides all other maps that would have been active, |
| 657 | except for the current global map. |
| 658 | @end defvar |
| 659 | |
| 660 | @defvar overriding-terminal-local-map |
| 661 | If non-@code{nil}, this variable holds a keymap to use instead of |
| 662 | @code{overriding-local-map}, the buffer's local keymap and all the minor |
| 663 | mode keymaps. |
| 664 | |
| 665 | This variable is always local to the current terminal and cannot be |
| 666 | buffer-local. @xref{Multiple Displays}. It is used to implement |
| 667 | incremental search mode. |
| 668 | @end defvar |
| 669 | |
| 670 | @defvar overriding-local-map-menu-flag |
| 671 | If this variable is non-@code{nil}, the value of |
| 672 | @code{overriding-local-map} or @code{overriding-terminal-local-map} can |
| 673 | affect the display of the menu bar. The default value is @code{nil}, so |
| 674 | those map variables have no effect on the menu bar. |
| 675 | |
| 676 | Note that these two map variables do affect the execution of key |
| 677 | sequences entered using the menu bar, even if they do not affect the |
| 678 | menu bar display. So if a menu bar key sequence comes in, you should |
| 679 | clear the variables before looking up and executing that key sequence. |
| 680 | Modes that use the variables would typically do this anyway; normally |
| 681 | they respond to events that they do not handle by ``unreading'' them and |
| 682 | exiting. |
| 683 | @end defvar |
| 684 | |
| 685 | @defvar special-event-map |
| 686 | This variable holds a keymap for special events. If an event type has a |
| 687 | binding in this keymap, then it is special, and the binding for the |
| 688 | event is run directly by @code{read-event}. @xref{Special Events}. |
| 689 | @end defvar |
| 690 | |
| 691 | @node Key Lookup |
| 692 | @section Key Lookup |
| 693 | @cindex key lookup |
| 694 | @cindex keymap entry |
| 695 | |
| 696 | @dfn{Key lookup} is the process of finding the binding of a key |
| 697 | sequence from a given keymap. Actual execution of the binding is not |
| 698 | part of key lookup. |
| 699 | |
| 700 | Key lookup uses just the event type of each event in the key sequence; |
| 701 | the rest of the event is ignored. In fact, a key sequence used for key |
| 702 | lookup may designate mouse events with just their types (symbols) |
| 703 | instead of with entire mouse events (lists). @xref{Input Events}. Such |
| 704 | a ``key-sequence'' is insufficient for @code{command-execute} to run, |
| 705 | but it is sufficient for looking up or rebinding a key. |
| 706 | |
| 707 | When the key sequence consists of multiple events, key lookup |
| 708 | processes the events sequentially: the binding of the first event is |
| 709 | found, and must be a keymap; then the second event's binding is found in |
| 710 | that keymap, and so on until all the events in the key sequence are used |
| 711 | up. (The binding thus found for the last event may or may not be a |
| 712 | keymap.) Thus, the process of key lookup is defined in terms of a |
| 713 | simpler process for looking up a single event in a keymap. How that is |
| 714 | done depends on the type of object associated with the event in that |
| 715 | keymap. |
| 716 | |
| 717 | Let's use the term @dfn{keymap entry} to describe the value found by |
| 718 | looking up an event type in a keymap. (This doesn't include the item |
| 719 | string and other extra elements in menu key bindings, because |
| 720 | @code{lookup-key} and other key lookup functions don't include them in |
| 721 | the returned value.) While any Lisp object may be stored in a keymap as |
| 722 | a keymap entry, not all make sense for key lookup. Here is a table of |
| 723 | the meaningful kinds of keymap entries: |
| 724 | |
| 725 | @table @asis |
| 726 | @item @code{nil} |
| 727 | @cindex @code{nil} in keymap |
| 728 | @code{nil} means that the events used so far in the lookup form an |
| 729 | undefined key. When a keymap fails to mention an event type at all, and |
| 730 | has no default binding, that is equivalent to a binding of @code{nil} |
| 731 | for that event type. |
| 732 | |
| 733 | @item @var{command} |
| 734 | @cindex command in keymap |
| 735 | The events used so far in the lookup form a complete key, |
| 736 | and @var{command} is its binding. @xref{What Is a Function}. |
| 737 | |
| 738 | @item @var{array} |
| 739 | @cindex string in keymap |
| 740 | The array (either a string or a vector) is a keyboard macro. The events |
| 741 | used so far in the lookup form a complete key, and the array is its |
| 742 | binding. See @ref{Keyboard Macros}, for more information. |
| 743 | |
| 744 | @item @var{keymap} |
| 745 | @cindex keymap in keymap |
| 746 | The events used so far in the lookup form a prefix key. The next |
| 747 | event of the key sequence is looked up in @var{keymap}. |
| 748 | |
| 749 | @item @var{list} |
| 750 | @cindex list in keymap |
| 751 | The meaning of a list depends on the types of the elements of the list. |
| 752 | |
| 753 | @itemize @bullet |
| 754 | @item |
| 755 | If the @sc{car} of @var{list} is the symbol @code{keymap}, then the list |
| 756 | is a keymap, and is treated as a keymap (see above). |
| 757 | |
| 758 | @item |
| 759 | @cindex @code{lambda} in keymap |
| 760 | If the @sc{car} of @var{list} is @code{lambda}, then the list is a |
| 761 | lambda expression. This is presumed to be a command, and is treated as |
| 762 | such (see above). |
| 763 | |
| 764 | @item |
| 765 | If the @sc{car} of @var{list} is a keymap and the @sc{cdr} is an event |
| 766 | type, then this is an @dfn{indirect entry}: |
| 767 | |
| 768 | @example |
| 769 | (@var{othermap} . @var{othertype}) |
| 770 | @end example |
| 771 | |
| 772 | When key lookup encounters an indirect entry, it looks up instead the |
| 773 | binding of @var{othertype} in @var{othermap} and uses that. |
| 774 | |
| 775 | This feature permits you to define one key as an alias for another key. |
| 776 | For example, an entry whose @sc{car} is the keymap called @code{esc-map} |
| 777 | and whose @sc{cdr} is 32 (the code for @key{SPC}) means, ``Use the global |
| 778 | binding of @kbd{Meta-@key{SPC}}, whatever that may be.'' |
| 779 | @end itemize |
| 780 | |
| 781 | @item @var{symbol} |
| 782 | @cindex symbol in keymap |
| 783 | The function definition of @var{symbol} is used in place of |
| 784 | @var{symbol}. If that too is a symbol, then this process is repeated, |
| 785 | any number of times. Ultimately this should lead to an object that is |
| 786 | a keymap, a command, or a keyboard macro. A list is allowed if it is a |
| 787 | keymap or a command, but indirect entries are not understood when found |
| 788 | via symbols. |
| 789 | |
| 790 | Note that keymaps and keyboard macros (strings and vectors) are not |
| 791 | valid functions, so a symbol with a keymap, string, or vector as its |
| 792 | function definition is invalid as a function. It is, however, valid as |
| 793 | a key binding. If the definition is a keyboard macro, then the symbol |
| 794 | is also valid as an argument to @code{command-execute} |
| 795 | (@pxref{Interactive Call}). |
| 796 | |
| 797 | @cindex @code{undefined} in keymap |
| 798 | The symbol @code{undefined} is worth special mention: it means to treat |
| 799 | the key as undefined. Strictly speaking, the key is defined, and its |
| 800 | binding is the command @code{undefined}; but that command does the same |
| 801 | thing that is done automatically for an undefined key: it rings the bell |
| 802 | (by calling @code{ding}) but does not signal an error. |
| 803 | |
| 804 | @cindex preventing prefix key |
| 805 | @code{undefined} is used in local keymaps to override a global key |
| 806 | binding and make the key ``undefined'' locally. A local binding of |
| 807 | @code{nil} would fail to do this because it would not override the |
| 808 | global binding. |
| 809 | |
| 810 | @item @var{anything else} |
| 811 | If any other type of object is found, the events used so far in the |
| 812 | lookup form a complete key, and the object is its binding, but the |
| 813 | binding is not executable as a command. |
| 814 | @end table |
| 815 | |
| 816 | In short, a keymap entry may be a keymap, a command, a keyboard macro, |
| 817 | a symbol that leads to one of them, or an indirection or @code{nil}. |
| 818 | Here is an example of a sparse keymap with two characters bound to |
| 819 | commands and one bound to another keymap. This map is the normal value |
| 820 | of @code{emacs-lisp-mode-map}. Note that 9 is the code for @key{TAB}, |
| 821 | 127 for @key{DEL}, 27 for @key{ESC}, 17 for @kbd{C-q} and 24 for |
| 822 | @kbd{C-x}. |
| 823 | |
| 824 | @example |
| 825 | @group |
| 826 | (keymap (9 . lisp-indent-line) |
| 827 | (127 . backward-delete-char-untabify) |
| 828 | (27 keymap (17 . indent-sexp) (24 . eval-defun))) |
| 829 | @end group |
| 830 | @end example |
| 831 | |
| 832 | @node Functions for Key Lookup |
| 833 | @section Functions for Key Lookup |
| 834 | |
| 835 | Here are the functions and variables pertaining to key lookup. |
| 836 | |
| 837 | @defun lookup-key keymap key &optional accept-defaults |
| 838 | This function returns the definition of @var{key} in @var{keymap}. All |
| 839 | the other functions described in this chapter that look up keys use |
| 840 | @code{lookup-key}. Here are examples: |
| 841 | |
| 842 | @example |
| 843 | @group |
| 844 | (lookup-key (current-global-map) "\C-x\C-f") |
| 845 | @result{} find-file |
| 846 | @end group |
| 847 | @group |
| 848 | (lookup-key (current-global-map) "\C-x\C-f12345") |
| 849 | @result{} 2 |
| 850 | @end group |
| 851 | @end example |
| 852 | |
| 853 | If the string or vector @var{key} is not a valid key sequence according |
| 854 | to the prefix keys specified in @var{keymap}, it must be ``too long'' |
| 855 | and have extra events at the end that do not fit into a single key |
| 856 | sequence. Then the value is a number, the number of events at the front |
| 857 | of @var{key} that compose a complete key. |
| 858 | |
| 859 | @c Emacs 19 feature |
| 860 | If @var{accept-defaults} is non-@code{nil}, then @code{lookup-key} |
| 861 | considers default bindings as well as bindings for the specific events |
| 862 | in @var{key}. Otherwise, @code{lookup-key} reports only bindings for |
| 863 | the specific sequence @var{key}, ignoring default bindings except when |
| 864 | you explicitly ask about them. (To do this, supply @code{t} as an |
| 865 | element of @var{key}; see @ref{Format of Keymaps}.) |
| 866 | |
| 867 | If @var{key} contains a meta character, that character is implicitly |
| 868 | replaced by a two-character sequence: the value of |
| 869 | @code{meta-prefix-char}, followed by the corresponding non-meta |
| 870 | character. Thus, the first example below is handled by conversion into |
| 871 | the second example. |
| 872 | |
| 873 | @example |
| 874 | @group |
| 875 | (lookup-key (current-global-map) "\M-f") |
| 876 | @result{} forward-word |
| 877 | @end group |
| 878 | @group |
| 879 | (lookup-key (current-global-map) "\ef") |
| 880 | @result{} forward-word |
| 881 | @end group |
| 882 | @end example |
| 883 | |
| 884 | Unlike @code{read-key-sequence}, this function does not modify the |
| 885 | specified events in ways that discard information (@pxref{Key Sequence |
| 886 | Input}). In particular, it does not convert letters to lower case and |
| 887 | it does not change drag events to clicks. |
| 888 | @end defun |
| 889 | |
| 890 | @deffn Command undefined |
| 891 | Used in keymaps to undefine keys. It calls @code{ding}, but does |
| 892 | not cause an error. |
| 893 | @end deffn |
| 894 | |
| 895 | @defun key-binding key &optional accept-defaults |
| 896 | This function returns the binding for @var{key} in the current |
| 897 | keymaps, trying all the active keymaps. The result is @code{nil} if |
| 898 | @var{key} is undefined in the keymaps. |
| 899 | |
| 900 | @c Emacs 19 feature |
| 901 | The argument @var{accept-defaults} controls checking for default |
| 902 | bindings, as in @code{lookup-key} (above). |
| 903 | |
| 904 | An error is signaled if @var{key} is not a string or a vector. |
| 905 | |
| 906 | @example |
| 907 | @group |
| 908 | (key-binding "\C-x\C-f") |
| 909 | @result{} find-file |
| 910 | @end group |
| 911 | @end example |
| 912 | @end defun |
| 913 | |
| 914 | @defun local-key-binding key &optional accept-defaults |
| 915 | This function returns the binding for @var{key} in the current |
| 916 | local keymap, or @code{nil} if it is undefined there. |
| 917 | |
| 918 | @c Emacs 19 feature |
| 919 | The argument @var{accept-defaults} controls checking for default bindings, |
| 920 | as in @code{lookup-key} (above). |
| 921 | @end defun |
| 922 | |
| 923 | @defun global-key-binding key &optional accept-defaults |
| 924 | This function returns the binding for command @var{key} in the |
| 925 | current global keymap, or @code{nil} if it is undefined there. |
| 926 | |
| 927 | @c Emacs 19 feature |
| 928 | The argument @var{accept-defaults} controls checking for default bindings, |
| 929 | as in @code{lookup-key} (above). |
| 930 | @end defun |
| 931 | |
| 932 | @c Emacs 19 feature |
| 933 | @defun minor-mode-key-binding key &optional accept-defaults |
| 934 | This function returns a list of all the active minor mode bindings of |
| 935 | @var{key}. More precisely, it returns an alist of pairs |
| 936 | @code{(@var{modename} . @var{binding})}, where @var{modename} is the |
| 937 | variable that enables the minor mode, and @var{binding} is @var{key}'s |
| 938 | binding in that mode. If @var{key} has no minor-mode bindings, the |
| 939 | value is @code{nil}. |
| 940 | |
| 941 | If the first binding found is not a prefix definition (a keymap or a |
| 942 | symbol defined as a keymap), all subsequent bindings from other minor |
| 943 | modes are omitted, since they would be completely shadowed. Similarly, |
| 944 | the list omits non-prefix bindings that follow prefix bindings. |
| 945 | |
| 946 | The argument @var{accept-defaults} controls checking for default |
| 947 | bindings, as in @code{lookup-key} (above). |
| 948 | @end defun |
| 949 | |
| 950 | @defvar meta-prefix-char |
| 951 | @cindex @key{ESC} |
| 952 | This variable is the meta-prefix character code. It is used when |
| 953 | translating a meta character to a two-character sequence so it can be |
| 954 | looked up in a keymap. For useful results, the value should be a prefix |
| 955 | event (@pxref{Prefix Keys}). The default value is 27, which is the |
| 956 | @sc{ascii} code for @key{ESC}. |
| 957 | |
| 958 | As long as the value of @code{meta-prefix-char} remains 27, key |
| 959 | lookup translates @kbd{M-b} into @kbd{@key{ESC} b}, which is normally |
| 960 | defined as the @code{backward-word} command. However, if you set |
| 961 | @code{meta-prefix-char} to 24, the code for @kbd{C-x}, then Emacs will |
| 962 | translate @kbd{M-b} into @kbd{C-x b}, whose standard binding is the |
| 963 | @code{switch-to-buffer} command. Here is an illustration: |
| 964 | |
| 965 | @smallexample |
| 966 | @group |
| 967 | meta-prefix-char ; @r{The default value.} |
| 968 | @result{} 27 |
| 969 | @end group |
| 970 | @group |
| 971 | (key-binding "\M-b") |
| 972 | @result{} backward-word |
| 973 | @end group |
| 974 | @group |
| 975 | ?\C-x ; @r{The print representation} |
| 976 | @result{} 24 ; @r{of a character.} |
| 977 | @end group |
| 978 | @group |
| 979 | (setq meta-prefix-char 24) |
| 980 | @result{} 24 |
| 981 | @end group |
| 982 | @group |
| 983 | (key-binding "\M-b") |
| 984 | @result{} switch-to-buffer ; @r{Now, typing @kbd{M-b} is} |
| 985 | ; @r{like typing @kbd{C-x b}.} |
| 986 | |
| 987 | (setq meta-prefix-char 27) ; @r{Avoid confusion!} |
| 988 | @result{} 27 ; @r{Restore the default value!} |
| 989 | @end group |
| 990 | @end smallexample |
| 991 | @end defvar |
| 992 | |
| 993 | @node Changing Key Bindings |
| 994 | @section Changing Key Bindings |
| 995 | @cindex changing key bindings |
| 996 | @cindex rebinding |
| 997 | |
| 998 | The way to rebind a key is to change its entry in a keymap. If you |
| 999 | change a binding in the global keymap, the change is effective in all |
| 1000 | buffers (though it has no direct effect in buffers that shadow the |
| 1001 | global binding with a local one). If you change the current buffer's |
| 1002 | local map, that usually affects all buffers using the same major mode. |
| 1003 | The @code{global-set-key} and @code{local-set-key} functions are |
| 1004 | convenient interfaces for these operations (@pxref{Key Binding |
| 1005 | Commands}). You can also use @code{define-key}, a more general |
| 1006 | function; then you must specify explicitly the map to change. |
| 1007 | |
| 1008 | @cindex meta character key constants |
| 1009 | @cindex control character key constants |
| 1010 | In writing the key sequence to rebind, it is good to use the special |
| 1011 | escape sequences for control and meta characters (@pxref{String Type}). |
| 1012 | The syntax @samp{\C-} means that the following character is a control |
| 1013 | character and @samp{\M-} means that the following character is a meta |
| 1014 | character. Thus, the string @code{"\M-x"} is read as containing a |
| 1015 | single @kbd{M-x}, @code{"\C-f"} is read as containing a single |
| 1016 | @kbd{C-f}, and @code{"\M-\C-x"} and @code{"\C-\M-x"} are both read as |
| 1017 | containing a single @kbd{C-M-x}. You can also use this escape syntax in |
| 1018 | vectors, as well as others that aren't allowed in strings; one example |
| 1019 | is @samp{[?\C-\H-x home]}. @xref{Character Type}. |
| 1020 | |
| 1021 | The key definition and lookup functions accept an alternate syntax for |
| 1022 | event types in a key sequence that is a vector: you can use a list |
| 1023 | containing modifier names plus one base event (a character or function |
| 1024 | key name). For example, @code{(control ?a)} is equivalent to |
| 1025 | @code{?\C-a} and @code{(hyper control left)} is equivalent to |
| 1026 | @code{C-H-left}. One advantage of such lists is that the precise |
| 1027 | numeric codes for the modifier bits don't appear in compiled files. |
| 1028 | |
| 1029 | For the functions below, an error is signaled if @var{keymap} is not a |
| 1030 | keymap or if @var{key} is not a string or vector representing a key |
| 1031 | sequence. You can use event types (symbols) as shorthand for events |
| 1032 | that are lists. |
| 1033 | |
| 1034 | @defun define-key keymap key binding |
| 1035 | This function sets the binding for @var{key} in @var{keymap}. (If |
| 1036 | @var{key} is more than one event long, the change is actually made |
| 1037 | in another keymap reached from @var{keymap}.) The argument |
| 1038 | @var{binding} can be any Lisp object, but only certain types are |
| 1039 | meaningful. (For a list of meaningful types, see @ref{Key Lookup}.) |
| 1040 | The value returned by @code{define-key} is @var{binding}. |
| 1041 | |
| 1042 | @cindex invalid prefix key error |
| 1043 | @cindex key sequence error |
| 1044 | Every prefix of @var{key} must be a prefix key (i.e., bound to a keymap) |
| 1045 | or undefined; otherwise an error is signaled. If some prefix of |
| 1046 | @var{key} is undefined, then @code{define-key} defines it as a prefix |
| 1047 | key so that the rest of @var{key} can be defined as specified. |
| 1048 | |
| 1049 | If there was previously no binding for @var{key} in @var{keymap}, the |
| 1050 | new binding is added at the beginning of @var{keymap}. The order of |
| 1051 | bindings in a keymap makes no difference in most cases, but it does |
| 1052 | matter for menu keymaps (@pxref{Menu Keymaps}). |
| 1053 | @end defun |
| 1054 | |
| 1055 | Here is an example that creates a sparse keymap and makes a number of |
| 1056 | bindings in it: |
| 1057 | |
| 1058 | @smallexample |
| 1059 | @group |
| 1060 | (setq map (make-sparse-keymap)) |
| 1061 | @result{} (keymap) |
| 1062 | @end group |
| 1063 | @group |
| 1064 | (define-key map "\C-f" 'forward-char) |
| 1065 | @result{} forward-char |
| 1066 | @end group |
| 1067 | @group |
| 1068 | map |
| 1069 | @result{} (keymap (6 . forward-char)) |
| 1070 | @end group |
| 1071 | |
| 1072 | @group |
| 1073 | ;; @r{Build sparse submap for @kbd{C-x} and bind @kbd{f} in that.} |
| 1074 | (define-key map "\C-xf" 'forward-word) |
| 1075 | @result{} forward-word |
| 1076 | @end group |
| 1077 | @group |
| 1078 | map |
| 1079 | @result{} (keymap |
| 1080 | (24 keymap ; @kbd{C-x} |
| 1081 | (102 . forward-word)) ; @kbd{f} |
| 1082 | (6 . forward-char)) ; @kbd{C-f} |
| 1083 | @end group |
| 1084 | |
| 1085 | @group |
| 1086 | ;; @r{Bind @kbd{C-p} to the @code{ctl-x-map}.} |
| 1087 | (define-key map "\C-p" ctl-x-map) |
| 1088 | ;; @code{ctl-x-map} |
| 1089 | @result{} [nil @dots{} find-file @dots{} backward-kill-sentence] |
| 1090 | @end group |
| 1091 | |
| 1092 | @group |
| 1093 | ;; @r{Bind @kbd{C-f} to @code{foo} in the @code{ctl-x-map}.} |
| 1094 | (define-key map "\C-p\C-f" 'foo) |
| 1095 | @result{} 'foo |
| 1096 | @end group |
| 1097 | @group |
| 1098 | map |
| 1099 | @result{} (keymap ; @r{Note @code{foo} in @code{ctl-x-map}.} |
| 1100 | (16 keymap [nil @dots{} foo @dots{} backward-kill-sentence]) |
| 1101 | (24 keymap |
| 1102 | (102 . forward-word)) |
| 1103 | (6 . forward-char)) |
| 1104 | @end group |
| 1105 | @end smallexample |
| 1106 | |
| 1107 | @noindent |
| 1108 | Note that storing a new binding for @kbd{C-p C-f} actually works by |
| 1109 | changing an entry in @code{ctl-x-map}, and this has the effect of |
| 1110 | changing the bindings of both @kbd{C-p C-f} and @kbd{C-x C-f} in the |
| 1111 | default global map. |
| 1112 | |
| 1113 | @defun substitute-key-definition olddef newdef keymap &optional oldmap |
| 1114 | @cindex replace bindings |
| 1115 | This function replaces @var{olddef} with @var{newdef} for any keys in |
| 1116 | @var{keymap} that were bound to @var{olddef}. In other words, |
| 1117 | @var{olddef} is replaced with @var{newdef} wherever it appears. The |
| 1118 | function returns @code{nil}. |
| 1119 | |
| 1120 | For example, this redefines @kbd{C-x C-f}, if you do it in an Emacs with |
| 1121 | standard bindings: |
| 1122 | |
| 1123 | @smallexample |
| 1124 | @group |
| 1125 | (substitute-key-definition |
| 1126 | 'find-file 'find-file-read-only (current-global-map)) |
| 1127 | @end group |
| 1128 | @end smallexample |
| 1129 | |
| 1130 | @c Emacs 19 feature |
| 1131 | If @var{oldmap} is non-@code{nil}, that changes the behavior of |
| 1132 | @code{substitute-key-definition}: the bindings in @var{oldmap} determine |
| 1133 | which keys to rebind. The rebindings still happen in @var{keymap}, not |
| 1134 | in @var{oldmap}. Thus, you can change one map under the control of the |
| 1135 | bindings in another. For example, |
| 1136 | |
| 1137 | @smallexample |
| 1138 | (substitute-key-definition |
| 1139 | 'delete-backward-char 'my-funny-delete |
| 1140 | my-map global-map) |
| 1141 | @end smallexample |
| 1142 | |
| 1143 | @noindent |
| 1144 | puts the special deletion command in @code{my-map} for whichever keys |
| 1145 | are globally bound to the standard deletion command. |
| 1146 | |
| 1147 | @ignore |
| 1148 | @c Emacs 18 only |
| 1149 | Prefix keymaps that appear within @var{keymap} are not checked |
| 1150 | recursively for keys bound to @var{olddef}; they are not changed at all. |
| 1151 | Perhaps it would be better to check nested keymaps recursively. |
| 1152 | @end ignore |
| 1153 | |
| 1154 | Here is an example showing a keymap before and after substitution: |
| 1155 | |
| 1156 | @smallexample |
| 1157 | @group |
| 1158 | (setq map '(keymap |
| 1159 | (?1 . olddef-1) |
| 1160 | (?2 . olddef-2) |
| 1161 | (?3 . olddef-1))) |
| 1162 | @result{} (keymap (49 . olddef-1) (50 . olddef-2) (51 . olddef-1)) |
| 1163 | @end group |
| 1164 | |
| 1165 | @group |
| 1166 | (substitute-key-definition 'olddef-1 'newdef map) |
| 1167 | @result{} nil |
| 1168 | @end group |
| 1169 | @group |
| 1170 | map |
| 1171 | @result{} (keymap (49 . newdef) (50 . olddef-2) (51 . newdef)) |
| 1172 | @end group |
| 1173 | @end smallexample |
| 1174 | @end defun |
| 1175 | |
| 1176 | @defun suppress-keymap keymap &optional nodigits |
| 1177 | @cindex @code{self-insert-command} override |
| 1178 | This function changes the contents of the full keymap @var{keymap} by |
| 1179 | making all the printing characters undefined. More precisely, it binds |
| 1180 | them to the command @code{undefined}. This makes ordinary insertion of |
| 1181 | text impossible. @code{suppress-keymap} returns @code{nil}. |
| 1182 | |
| 1183 | If @var{nodigits} is @code{nil}, then @code{suppress-keymap} defines |
| 1184 | digits to run @code{digit-argument}, and @kbd{-} to run |
| 1185 | @code{negative-argument}. Otherwise it makes them undefined like the |
| 1186 | rest of the printing characters. |
| 1187 | |
| 1188 | @cindex yank suppression |
| 1189 | @cindex @code{quoted-insert} suppression |
| 1190 | The @code{suppress-keymap} function does not make it impossible to |
| 1191 | modify a buffer, as it does not suppress commands such as @code{yank} |
| 1192 | and @code{quoted-insert}. To prevent any modification of a buffer, make |
| 1193 | it read-only (@pxref{Read Only Buffers}). |
| 1194 | |
| 1195 | Since this function modifies @var{keymap}, you would normally use it |
| 1196 | on a newly created keymap. Operating on an existing keymap |
| 1197 | that is used for some other purpose is likely to cause trouble; for |
| 1198 | example, suppressing @code{global-map} would make it impossible to use |
| 1199 | most of Emacs. |
| 1200 | |
| 1201 | Most often, @code{suppress-keymap} is used to initialize local |
| 1202 | keymaps of modes such as Rmail and Dired where insertion of text is not |
| 1203 | desirable and the buffer is read-only. Here is an example taken from |
| 1204 | the file @file{emacs/lisp/dired.el}, showing how the local keymap for |
| 1205 | Dired mode is set up: |
| 1206 | |
| 1207 | @smallexample |
| 1208 | @group |
| 1209 | (setq dired-mode-map (make-keymap)) |
| 1210 | (suppress-keymap dired-mode-map) |
| 1211 | (define-key dired-mode-map "r" 'dired-rename-file) |
| 1212 | (define-key dired-mode-map "\C-d" 'dired-flag-file-deleted) |
| 1213 | (define-key dired-mode-map "d" 'dired-flag-file-deleted) |
| 1214 | (define-key dired-mode-map "v" 'dired-view-file) |
| 1215 | (define-key dired-mode-map "e" 'dired-find-file) |
| 1216 | (define-key dired-mode-map "f" 'dired-find-file) |
| 1217 | @dots{} |
| 1218 | @end group |
| 1219 | @end smallexample |
| 1220 | @end defun |
| 1221 | |
| 1222 | @node Key Binding Commands |
| 1223 | @section Commands for Binding Keys |
| 1224 | |
| 1225 | This section describes some convenient interactive interfaces for |
| 1226 | changing key bindings. They work by calling @code{define-key}. |
| 1227 | |
| 1228 | People often use @code{global-set-key} in their init files |
| 1229 | (@pxref{Init File}) for simple customization. For example, |
| 1230 | |
| 1231 | @smallexample |
| 1232 | (global-set-key "\C-x\C-\\" 'next-line) |
| 1233 | @end smallexample |
| 1234 | |
| 1235 | @noindent |
| 1236 | or |
| 1237 | |
| 1238 | @smallexample |
| 1239 | (global-set-key [?\C-x ?\C-\\] 'next-line) |
| 1240 | @end smallexample |
| 1241 | |
| 1242 | @noindent |
| 1243 | or |
| 1244 | |
| 1245 | @smallexample |
| 1246 | (global-set-key [(control ?x) (control ?\\)] 'next-line) |
| 1247 | @end smallexample |
| 1248 | |
| 1249 | @noindent |
| 1250 | redefines @kbd{C-x C-\} to move down a line. |
| 1251 | |
| 1252 | @smallexample |
| 1253 | (global-set-key [M-mouse-1] 'mouse-set-point) |
| 1254 | @end smallexample |
| 1255 | |
| 1256 | @noindent |
| 1257 | redefines the first (leftmost) mouse button, typed with the Meta key, to |
| 1258 | set point where you click. |
| 1259 | |
| 1260 | @cindex non-@sc{ascii} text in keybindings |
| 1261 | Be careful when using non-@sc{ascii} text characters in Lisp |
| 1262 | specifications of keys to bind. If these are read as multibyte text, as |
| 1263 | they usually will be in a Lisp file (@pxref{Loading Non-ASCII}), you |
| 1264 | must type the keys as multibyte too. For instance, if you use this: |
| 1265 | |
| 1266 | @smallexample |
| 1267 | (global-set-key "@"o" 'my-function) ; bind o-umlaut |
| 1268 | @end smallexample |
| 1269 | |
| 1270 | @noindent |
| 1271 | or |
| 1272 | |
| 1273 | @smallexample |
| 1274 | (global-set-key ?@"o 'my-function) ; bind o-umlaut |
| 1275 | @end smallexample |
| 1276 | |
| 1277 | @noindent |
| 1278 | and your language environment is multibyte Latin-1, these commands |
| 1279 | actually bind the multibyte character with code 2294, not the unibyte |
| 1280 | Latin-1 character with code 246 (@kbd{M-v}). In order to use this |
| 1281 | binding, you need to enter the multibyte Latin-1 character as keyboard |
| 1282 | input. One way to do this is by using an appropriate input method |
| 1283 | (@pxref{Input Methods, , Input Methods, emacs,The GNU Emacs Manual}). |
| 1284 | |
| 1285 | If you want to use a unibyte character in the key binding, you can |
| 1286 | construct the key sequence string using @code{multibyte-char-to-unibyte} |
| 1287 | or @code{string-make-unibyte} (@pxref{Converting Representations}). |
| 1288 | |
| 1289 | @deffn Command global-set-key key definition |
| 1290 | This function sets the binding of @var{key} in the current global map |
| 1291 | to @var{definition}. |
| 1292 | |
| 1293 | @smallexample |
| 1294 | @group |
| 1295 | (global-set-key @var{key} @var{definition}) |
| 1296 | @equiv{} |
| 1297 | (define-key (current-global-map) @var{key} @var{definition}) |
| 1298 | @end group |
| 1299 | @end smallexample |
| 1300 | @end deffn |
| 1301 | |
| 1302 | @deffn Command global-unset-key key |
| 1303 | @cindex unbinding keys |
| 1304 | This function removes the binding of @var{key} from the current |
| 1305 | global map. |
| 1306 | |
| 1307 | One use of this function is in preparation for defining a longer key |
| 1308 | that uses @var{key} as a prefix---which would not be allowed if |
| 1309 | @var{key} has a non-prefix binding. For example: |
| 1310 | |
| 1311 | @smallexample |
| 1312 | @group |
| 1313 | (global-unset-key "\C-l") |
| 1314 | @result{} nil |
| 1315 | @end group |
| 1316 | @group |
| 1317 | (global-set-key "\C-l\C-l" 'redraw-display) |
| 1318 | @result{} nil |
| 1319 | @end group |
| 1320 | @end smallexample |
| 1321 | |
| 1322 | This function is implemented simply using @code{define-key}: |
| 1323 | |
| 1324 | @smallexample |
| 1325 | @group |
| 1326 | (global-unset-key @var{key}) |
| 1327 | @equiv{} |
| 1328 | (define-key (current-global-map) @var{key} nil) |
| 1329 | @end group |
| 1330 | @end smallexample |
| 1331 | @end deffn |
| 1332 | |
| 1333 | @deffn Command local-set-key key definition |
| 1334 | This function sets the binding of @var{key} in the current local |
| 1335 | keymap to @var{definition}. |
| 1336 | |
| 1337 | @smallexample |
| 1338 | @group |
| 1339 | (local-set-key @var{key} @var{definition}) |
| 1340 | @equiv{} |
| 1341 | (define-key (current-local-map) @var{key} @var{definition}) |
| 1342 | @end group |
| 1343 | @end smallexample |
| 1344 | @end deffn |
| 1345 | |
| 1346 | @deffn Command local-unset-key key |
| 1347 | This function removes the binding of @var{key} from the current |
| 1348 | local map. |
| 1349 | |
| 1350 | @smallexample |
| 1351 | @group |
| 1352 | (local-unset-key @var{key}) |
| 1353 | @equiv{} |
| 1354 | (define-key (current-local-map) @var{key} nil) |
| 1355 | @end group |
| 1356 | @end smallexample |
| 1357 | @end deffn |
| 1358 | |
| 1359 | @node Scanning Keymaps |
| 1360 | @section Scanning Keymaps |
| 1361 | |
| 1362 | This section describes functions used to scan all the current keymaps |
| 1363 | for the sake of printing help information. |
| 1364 | |
| 1365 | @defun accessible-keymaps keymap &optional prefix |
| 1366 | This function returns a list of all the keymaps that can be reached (via |
| 1367 | zero or more prefix keys) from @var{keymap}. The value is an |
| 1368 | association list with elements of the form @code{(@var{key} .@: |
| 1369 | @var{map})}, where @var{key} is a prefix key whose definition in |
| 1370 | @var{keymap} is @var{map}. |
| 1371 | |
| 1372 | The elements of the alist are ordered so that the @var{key} increases |
| 1373 | in length. The first element is always @code{("" .@: @var{keymap})}, |
| 1374 | because the specified keymap is accessible from itself with a prefix of |
| 1375 | no events. |
| 1376 | |
| 1377 | If @var{prefix} is given, it should be a prefix key sequence; then |
| 1378 | @code{accessible-keymaps} includes only the submaps whose prefixes start |
| 1379 | with @var{prefix}. These elements look just as they do in the value of |
| 1380 | @code{(accessible-keymaps)}; the only difference is that some elements |
| 1381 | are omitted. |
| 1382 | |
| 1383 | In the example below, the returned alist indicates that the key |
| 1384 | @key{ESC}, which is displayed as @samp{^[}, is a prefix key whose |
| 1385 | definition is the sparse keymap @code{(keymap (83 .@: center-paragraph) |
| 1386 | (115 .@: foo))}. |
| 1387 | |
| 1388 | @smallexample |
| 1389 | @group |
| 1390 | (accessible-keymaps (current-local-map)) |
| 1391 | @result{}(("" keymap |
| 1392 | (27 keymap ; @r{Note this keymap for @key{ESC} is repeated below.} |
| 1393 | (83 . center-paragraph) |
| 1394 | (115 . center-line)) |
| 1395 | (9 . tab-to-tab-stop)) |
| 1396 | @end group |
| 1397 | |
| 1398 | @group |
| 1399 | ("^[" keymap |
| 1400 | (83 . center-paragraph) |
| 1401 | (115 . foo))) |
| 1402 | @end group |
| 1403 | @end smallexample |
| 1404 | |
| 1405 | In the following example, @kbd{C-h} is a prefix key that uses a sparse |
| 1406 | keymap starting with @code{(keymap (118 . describe-variable)@dots{})}. |
| 1407 | Another prefix, @kbd{C-x 4}, uses a keymap which is also the value of |
| 1408 | the variable @code{ctl-x-4-map}. The event @code{mode-line} is one of |
| 1409 | several dummy events used as prefixes for mouse actions in special parts |
| 1410 | of a window. |
| 1411 | |
| 1412 | @smallexample |
| 1413 | @group |
| 1414 | (accessible-keymaps (current-global-map)) |
| 1415 | @result{} (("" keymap [set-mark-command beginning-of-line @dots{} |
| 1416 | delete-backward-char]) |
| 1417 | @end group |
| 1418 | @group |
| 1419 | ("^H" keymap (118 . describe-variable) @dots{} |
| 1420 | (8 . help-for-help)) |
| 1421 | @end group |
| 1422 | @group |
| 1423 | ("^X" keymap [x-flush-mouse-queue @dots{} |
| 1424 | backward-kill-sentence]) |
| 1425 | @end group |
| 1426 | @group |
| 1427 | ("^[" keymap [mark-sexp backward-sexp @dots{} |
| 1428 | backward-kill-word]) |
| 1429 | @end group |
| 1430 | ("^X4" keymap (15 . display-buffer) @dots{}) |
| 1431 | @group |
| 1432 | ([mode-line] keymap |
| 1433 | (S-mouse-2 . mouse-split-window-horizontally) @dots{})) |
| 1434 | @end group |
| 1435 | @end smallexample |
| 1436 | |
| 1437 | @noindent |
| 1438 | These are not all the keymaps you would see in actuality. |
| 1439 | @end defun |
| 1440 | |
| 1441 | @defun where-is-internal command &optional keymap firstonly noindirect |
| 1442 | This function is a subroutine used by the @code{where-is} command |
| 1443 | (@pxref{Help, , Help, emacs,The GNU Emacs Manual}). It returns a list |
| 1444 | of key sequences (of any length) that are bound to @var{command} in a |
| 1445 | set of keymaps. |
| 1446 | |
| 1447 | The argument @var{command} can be any object; it is compared with all |
| 1448 | keymap entries using @code{eq}. |
| 1449 | |
| 1450 | If @var{keymap} is @code{nil}, then the maps used are the current active |
| 1451 | keymaps, disregarding @code{overriding-local-map} (that is, pretending |
| 1452 | its value is @code{nil}). If @var{keymap} is non-@code{nil}, then the |
| 1453 | maps searched are @var{keymap} and the global keymap. |
| 1454 | |
| 1455 | Usually it's best to use @code{overriding-local-map} as the expression |
| 1456 | for @var{keymap}. Then @code{where-is-internal} searches precisely the |
| 1457 | keymaps that are active. To search only the global map, pass |
| 1458 | @code{(keymap)} (an empty keymap) as @var{keymap}. |
| 1459 | |
| 1460 | If @var{firstonly} is @code{non-ascii}, then the value is a single |
| 1461 | string representing the first key sequence found, rather than a list of |
| 1462 | all possible key sequences. If @var{firstonly} is @code{t}, then the |
| 1463 | value is the first key sequence, except that key sequences consisting |
| 1464 | entirely of @sc{ascii} characters (or meta variants of @sc{ascii} |
| 1465 | characters) are preferred to all other key sequences. |
| 1466 | |
| 1467 | If @var{noindirect} is non-@code{nil}, @code{where-is-internal} doesn't |
| 1468 | follow indirect keymap bindings. This makes it possible to search for |
| 1469 | an indirect definition itself. |
| 1470 | |
| 1471 | @smallexample |
| 1472 | @group |
| 1473 | (where-is-internal 'describe-function) |
| 1474 | @result{} ("\^hf" "\^hd") |
| 1475 | @end group |
| 1476 | @end smallexample |
| 1477 | @end defun |
| 1478 | |
| 1479 | @deffn Command describe-bindings &optional prefix |
| 1480 | This function creates a listing of all current key bindings, and |
| 1481 | displays it in a buffer named @samp{*Help*}. The text is grouped by |
| 1482 | modes---minor modes first, then the major mode, then global bindings. |
| 1483 | |
| 1484 | If @var{prefix} is non-@code{nil}, it should be a prefix key; then the |
| 1485 | listing includes only keys that start with @var{prefix}. |
| 1486 | |
| 1487 | The listing describes meta characters as @key{ESC} followed by the |
| 1488 | corresponding non-meta character. |
| 1489 | |
| 1490 | When several characters with consecutive @sc{ascii} codes have the |
| 1491 | same definition, they are shown together, as |
| 1492 | @samp{@var{firstchar}..@var{lastchar}}. In this instance, you need to |
| 1493 | know the @sc{ascii} codes to understand which characters this means. |
| 1494 | For example, in the default global map, the characters @samp{@key{SPC} |
| 1495 | ..@: ~} are described by a single line. @key{SPC} is @sc{ascii} 32, |
| 1496 | @kbd{~} is @sc{ascii} 126, and the characters between them include all |
| 1497 | the normal printing characters, (e.g., letters, digits, punctuation, |
| 1498 | etc.@:); all these characters are bound to @code{self-insert-command}. |
| 1499 | @end deffn |
| 1500 | |
| 1501 | @node Menu Keymaps |
| 1502 | @section Menu Keymaps |
| 1503 | @cindex menu keymaps |
| 1504 | |
| 1505 | @c Emacs 19 feature |
| 1506 | A keymap can define a menu as well as bindings for keyboard keys and |
| 1507 | mouse button. Menus are usually actuated with the mouse, but they can |
| 1508 | work with the keyboard also. |
| 1509 | |
| 1510 | @menu |
| 1511 | * Defining Menus:: How to make a keymap that defines a menu. |
| 1512 | * Mouse Menus:: How users actuate the menu with the mouse. |
| 1513 | * Keyboard Menus:: How they actuate it with the keyboard. |
| 1514 | * Menu Example:: Making a simple menu. |
| 1515 | * Menu Bar:: How to customize the menu bar. |
| 1516 | * Tool Bar:: A tool bar is a row of images. |
| 1517 | * Modifying Menus:: How to add new items to a menu. |
| 1518 | @end menu |
| 1519 | |
| 1520 | @node Defining Menus |
| 1521 | @subsection Defining Menus |
| 1522 | @cindex defining menus |
| 1523 | @cindex menu prompt string |
| 1524 | @cindex prompt string (of menu) |
| 1525 | |
| 1526 | A keymap is suitable for menu use if it has an @dfn{overall prompt |
| 1527 | string}, which is a string that appears as an element of the keymap. |
| 1528 | (@xref{Format of Keymaps}.) The string should describe the purpose of |
| 1529 | the menu's commands. Emacs displays the overall prompt string as the |
| 1530 | menu title in some cases, depending on the toolkit (if any) used for |
| 1531 | displaying menus.@footnote{It is required for menus which do not use a |
| 1532 | toolkit, e.g.@: under MS-DOS.} Keyboard menus also display the overall |
| 1533 | prompt string. |
| 1534 | |
| 1535 | The easiest way to construct a keymap with a prompt string is to specify |
| 1536 | the string as an argument when you call @code{make-keymap}, |
| 1537 | @code{make-sparse-keymap} or @code{define-prefix-command} |
| 1538 | (@pxref{Creating Keymaps}). |
| 1539 | |
| 1540 | The order of items in the menu is the same as the order of bindings in |
| 1541 | the keymap. Since @code{define-key} puts new bindings at the front, you |
| 1542 | should define the menu items starting at the bottom of the menu and |
| 1543 | moving to the top, if you care about the order. When you add an item to |
| 1544 | an existing menu, you can specify its position in the menu using |
| 1545 | @code{define-key-after} (@pxref{Modifying Menus}). |
| 1546 | |
| 1547 | @menu |
| 1548 | * Simple Menu Items:: A simple kind of menu key binding, |
| 1549 | limited in capabilities. |
| 1550 | * Extended Menu Items:: More powerful menu item definitions |
| 1551 | let you specify keywords to enable |
| 1552 | various features. |
| 1553 | * Menu Separators:: Drawing a horizontal line through a menu. |
| 1554 | * Alias Menu Items:: Using command aliases in menu items. |
| 1555 | @end menu |
| 1556 | |
| 1557 | @node Simple Menu Items |
| 1558 | @subsubsection Simple Menu Items |
| 1559 | |
| 1560 | The simpler and older way to define a menu keymap binding |
| 1561 | looks like this: |
| 1562 | |
| 1563 | @example |
| 1564 | (@var{item-string} . @var{real-binding}) |
| 1565 | @end example |
| 1566 | |
| 1567 | @noindent |
| 1568 | The @sc{car}, @var{item-string}, is the string to be displayed in the |
| 1569 | menu. It should be short---preferably one to three words. It should |
| 1570 | describe the action of the command it corresponds to. |
| 1571 | |
| 1572 | You can also supply a second string, called the help string, as follows: |
| 1573 | |
| 1574 | @example |
| 1575 | (@var{item-string} @var{help} . @var{real-binding}) |
| 1576 | @end example |
| 1577 | |
| 1578 | @var{help} specifies a ``help-echo'' string to display while the mouse |
| 1579 | is on that item in the same way as @code{help-echo} text properties |
| 1580 | (@pxref{Help display}). |
| 1581 | |
| 1582 | As far as @code{define-key} is concerned, @var{item-string} and |
| 1583 | @var{help-string} are part of the event's binding. However, |
| 1584 | @code{lookup-key} returns just @var{real-binding}, and only |
| 1585 | @var{real-binding} is used for executing the key. |
| 1586 | |
| 1587 | If @var{real-binding} is @code{nil}, then @var{item-string} appears in |
| 1588 | the menu but cannot be selected. |
| 1589 | |
| 1590 | If @var{real-binding} is a symbol and has a non-@code{nil} |
| 1591 | @code{menu-enable} property, that property is an expression that |
| 1592 | controls whether the menu item is enabled. Every time the keymap is |
| 1593 | used to display a menu, Emacs evaluates the expression, and it enables |
| 1594 | the menu item only if the expression's value is non-@code{nil}. When a |
| 1595 | menu item is disabled, it is displayed in a ``fuzzy'' fashion, and |
| 1596 | cannot be selected. |
| 1597 | |
| 1598 | The menu bar does not recalculate which items are enabled every time you |
| 1599 | look at a menu. This is because the X toolkit requires the whole tree |
| 1600 | of menus in advance. To force recalculation of the menu bar, call |
| 1601 | @code{force-mode-line-update} (@pxref{Mode Line Format}). |
| 1602 | |
| 1603 | You've probably noticed that menu items show the equivalent keyboard key |
| 1604 | sequence (if any) to invoke the same command. To save time on |
| 1605 | recalculation, menu display caches this information in a sublist in the |
| 1606 | binding, like this: |
| 1607 | |
| 1608 | @c This line is not too long--rms. |
| 1609 | @example |
| 1610 | (@var{item-string} @r{[}@var{help-string}@r{]} (@var{key-binding-data}) . @var{real-binding}) |
| 1611 | @end example |
| 1612 | |
| 1613 | @noindent |
| 1614 | Don't put these sublists in the menu item yourself; menu display |
| 1615 | calculates them automatically. Don't mention keyboard equivalents in |
| 1616 | the item strings themselves, since that is redundant. |
| 1617 | |
| 1618 | @node Extended Menu Items |
| 1619 | @subsubsection Extended Menu Items |
| 1620 | @kindex menu-item |
| 1621 | |
| 1622 | An extended-format menu item is a more flexible and also cleaner |
| 1623 | alternative to the simple format. It consists of a list that starts |
| 1624 | with the symbol @code{menu-item}. To define a non-selectable string, |
| 1625 | the item looks like this: |
| 1626 | |
| 1627 | @example |
| 1628 | (menu-item @var{item-name}) |
| 1629 | @end example |
| 1630 | |
| 1631 | @noindent |
| 1632 | A string starting with two or more dashes specifies a separator line; |
| 1633 | see @ref{Menu Separators}. |
| 1634 | |
| 1635 | To define a real menu item which can be selected, the extended format |
| 1636 | item looks like this: |
| 1637 | |
| 1638 | @example |
| 1639 | (menu-item @var{item-name} @var{real-binding} |
| 1640 | . @var{item-property-list}) |
| 1641 | @end example |
| 1642 | |
| 1643 | @noindent |
| 1644 | Here, @var{item-name} is an expression which evaluates to the menu item |
| 1645 | string. Thus, the string need not be a constant. The third element, |
| 1646 | @var{real-binding}, is the command to execute. The tail of the list, |
| 1647 | @var{item-property-list}, has the form of a property list which contains |
| 1648 | other information. Here is a table of the properties that are supported: |
| 1649 | |
| 1650 | @table @code |
| 1651 | @item :enable @var{form} |
| 1652 | The result of evaluating @var{form} determines whether the item is |
| 1653 | enabled (non-@code{nil} means yes). If the item is not enabled, |
| 1654 | you can't really click on it. |
| 1655 | |
| 1656 | @item :visible @var{form} |
| 1657 | The result of evaluating @var{form} determines whether the item should |
| 1658 | actually appear in the menu (non-@code{nil} means yes). If the item |
| 1659 | does not appear, then the menu is displayed as if this item were |
| 1660 | not defined at all. |
| 1661 | |
| 1662 | @item :help @var{help} |
| 1663 | The value of this property, @var{help}, specifies a ``help-echo'' string |
| 1664 | to display while the mouse is on that item. This is displayed in the |
| 1665 | same way as @code{help-echo} text properties (@pxref{Help display}). |
| 1666 | Note that this must be a constant string, unlike the @code{help-echo} |
| 1667 | property for text and overlays. |
| 1668 | |
| 1669 | @item :button (@var{type} . @var{selected}) |
| 1670 | This property provides a way to define radio buttons and toggle buttons. |
| 1671 | The @sc{car}, @var{type}, says which: it should be @code{:toggle} or |
| 1672 | @code{:radio}. The @sc{cdr}, @var{selected}, should be a form; the |
| 1673 | result of evaluating it says whether this button is currently selected. |
| 1674 | |
| 1675 | A @dfn{toggle} is a menu item which is labeled as either ``on'' or ``off'' |
| 1676 | according to the value of @var{selected}. The command itself should |
| 1677 | toggle @var{selected}, setting it to @code{t} if it is @code{nil}, |
| 1678 | and to @code{nil} if it is @code{t}. Here is how the menu item |
| 1679 | to toggle the @code{debug-on-error} flag is defined: |
| 1680 | |
| 1681 | @example |
| 1682 | (menu-item "Debug on Error" toggle-debug-on-error |
| 1683 | :button (:toggle |
| 1684 | . (and (boundp 'debug-on-error) |
| 1685 | debug-on-error))) |
| 1686 | @end example |
| 1687 | |
| 1688 | @noindent |
| 1689 | This works because @code{toggle-debug-on-error} is defined as a command |
| 1690 | which toggles the variable @code{debug-on-error}. |
| 1691 | |
| 1692 | @dfn{Radio buttons} are a group of menu items, in which at any time one |
| 1693 | and only one is ``selected.'' There should be a variable whose value |
| 1694 | says which one is selected at any time. The @var{selected} form for |
| 1695 | each radio button in the group should check whether the variable has the |
| 1696 | right value for selecting that button. Clicking on the button should |
| 1697 | set the variable so that the button you clicked on becomes selected. |
| 1698 | |
| 1699 | @item :key-sequence @var{key-sequence} |
| 1700 | This property specifies which key sequence is likely to be bound to the |
| 1701 | same command invoked by this menu item. If you specify the right key |
| 1702 | sequence, that makes preparing the menu for display run much faster. |
| 1703 | |
| 1704 | If you specify the wrong key sequence, it has no effect; before Emacs |
| 1705 | displays @var{key-sequence} in the menu, it verifies that |
| 1706 | @var{key-sequence} is really equivalent to this menu item. |
| 1707 | |
| 1708 | @item :key-sequence nil |
| 1709 | This property indicates that there is normally no key binding which is |
| 1710 | equivalent to this menu item. Using this property saves time in |
| 1711 | preparing the menu for display, because Emacs does not need to search |
| 1712 | the keymaps for a keyboard equivalent for this menu item. |
| 1713 | |
| 1714 | However, if the user has rebound this item's definition to a key |
| 1715 | sequence, Emacs ignores the @code{:keys} property and finds the keyboard |
| 1716 | equivalent anyway. |
| 1717 | |
| 1718 | @item :keys @var{string} |
| 1719 | This property specifies that @var{string} is the string to display |
| 1720 | as the keyboard equivalent for this menu item. You can use |
| 1721 | the @samp{\\[...]} documentation construct in @var{string}. |
| 1722 | |
| 1723 | @item :filter @var{filter-fn} |
| 1724 | This property provides a way to compute the menu item dynamically. |
| 1725 | The property value @var{filter-fn} should be a function of one argument; |
| 1726 | when it is called, its argument will be @var{real-binding}. The |
| 1727 | function should return the binding to use instead. |
| 1728 | @end table |
| 1729 | |
| 1730 | @node Menu Separators |
| 1731 | @subsubsection Menu Separators |
| 1732 | @cindex menu separators |
| 1733 | |
| 1734 | A menu separator is a kind of menu item that doesn't display any |
| 1735 | text--instead, it divides the menu into subparts with a horizontal line. |
| 1736 | A separator looks like this in the menu keymap: |
| 1737 | |
| 1738 | @example |
| 1739 | (menu-item @var{separator-type}) |
| 1740 | @end example |
| 1741 | |
| 1742 | @noindent |
| 1743 | where @var{separator-type} is a string starting with two or more dashes. |
| 1744 | |
| 1745 | In the simplest case, @var{separator-type} consists of only dashes. |
| 1746 | That specifies the default kind of separator. (For compatibility, |
| 1747 | @code{""} and @code{-} also count as separators.) |
| 1748 | |
| 1749 | Starting in Emacs 21, certain other values of @var{separator-type} |
| 1750 | specify a different style of separator. Here is a table of them: |
| 1751 | |
| 1752 | @table @code |
| 1753 | @item "--no-line" |
| 1754 | @itemx "--space" |
| 1755 | An extra vertical space, with no actual line. |
| 1756 | |
| 1757 | @item "--single-line" |
| 1758 | A single line in the menu's foreground color. |
| 1759 | |
| 1760 | @item "--double-line" |
| 1761 | A double line in the menu's foreground color. |
| 1762 | |
| 1763 | @item "--single-dashed-line" |
| 1764 | A single dashed line in the menu's foreground color. |
| 1765 | |
| 1766 | @item "--double-dashed-line" |
| 1767 | A double dashed line in the menu's foreground color. |
| 1768 | |
| 1769 | @item "--shadow-etched-in" |
| 1770 | A single line with a 3D sunken appearance. This is the default, |
| 1771 | used separators consisting of dashes only. |
| 1772 | |
| 1773 | @item "--shadow-etched-out" |
| 1774 | A single line with a 3D raised appearance. |
| 1775 | |
| 1776 | @item "--shadow-etched-in-dash" |
| 1777 | A single dashed line with a 3D sunken appearance. |
| 1778 | |
| 1779 | @item "--shadow-etched-out-dash" |
| 1780 | A single dashed line with a 3D raised appearance. |
| 1781 | |
| 1782 | @item "--shadow-double-etched-in" |
| 1783 | Two lines with a 3D sunken appearance. |
| 1784 | |
| 1785 | @item "--shadow-double-etched-out" |
| 1786 | Two lines with a 3D raised appearance. |
| 1787 | |
| 1788 | @item "--shadow-double-etched-in-dash" |
| 1789 | Two dashed lines with a 3D sunken appearance. |
| 1790 | |
| 1791 | @item "--shadow-double-etched-out-dash" |
| 1792 | Two dashed lines with a 3D raised appearance. |
| 1793 | @end table |
| 1794 | |
| 1795 | You can also give these names in another style, adding a colon after |
| 1796 | the double-dash and replacing each single dash with capitalization of |
| 1797 | the following word. Thus, @code{"--:singleLine"}, is equivalent to |
| 1798 | @code{"--single-line"}. |
| 1799 | |
| 1800 | Some systems and display toolkits don't really handle all of these |
| 1801 | separator types. If you use a type that isn't supported, the menu |
| 1802 | displays a similar kind of separator that is supported. |
| 1803 | |
| 1804 | @node Alias Menu Items |
| 1805 | @subsubsection Alias Menu Items |
| 1806 | |
| 1807 | Sometimes it is useful to make menu items that use the ``same'' |
| 1808 | command but with different enable conditions. The best way to do this |
| 1809 | in Emacs now is with extended menu items; before that feature existed, |
| 1810 | it could be done by defining alias commands and using them in menu |
| 1811 | items. Here's an example that makes two aliases for |
| 1812 | @code{toggle-read-only} and gives them different enable conditions: |
| 1813 | |
| 1814 | @example |
| 1815 | (defalias 'make-read-only 'toggle-read-only) |
| 1816 | (put 'make-read-only 'menu-enable '(not buffer-read-only)) |
| 1817 | (defalias 'make-writable 'toggle-read-only) |
| 1818 | (put 'make-writable 'menu-enable 'buffer-read-only) |
| 1819 | @end example |
| 1820 | |
| 1821 | When using aliases in menus, often it is useful to display the |
| 1822 | equivalent key bindings for the ``real'' command name, not the aliases |
| 1823 | (which typically don't have any key bindings except for the menu |
| 1824 | itself). To request this, give the alias symbol a non-@code{nil} |
| 1825 | @code{menu-alias} property. Thus, |
| 1826 | |
| 1827 | @example |
| 1828 | (put 'make-read-only 'menu-alias t) |
| 1829 | (put 'make-writable 'menu-alias t) |
| 1830 | @end example |
| 1831 | |
| 1832 | @noindent |
| 1833 | causes menu items for @code{make-read-only} and @code{make-writable} to |
| 1834 | show the keyboard bindings for @code{toggle-read-only}. |
| 1835 | |
| 1836 | @node Mouse Menus |
| 1837 | @subsection Menus and the Mouse |
| 1838 | |
| 1839 | The usual way to make a menu keymap produce a menu is to make it the |
| 1840 | definition of a prefix key. (A Lisp program can explicitly pop up a |
| 1841 | menu and receive the user's choice---see @ref{Pop-Up Menus}.) |
| 1842 | |
| 1843 | If the prefix key ends with a mouse event, Emacs handles the menu keymap |
| 1844 | by popping up a visible menu, so that the user can select a choice with |
| 1845 | the mouse. When the user clicks on a menu item, the event generated is |
| 1846 | whatever character or symbol has the binding that brought about that |
| 1847 | menu item. (A menu item may generate a series of events if the menu has |
| 1848 | multiple levels or comes from the menu bar.) |
| 1849 | |
| 1850 | It's often best to use a button-down event to trigger the menu. Then |
| 1851 | the user can select a menu item by releasing the button. |
| 1852 | |
| 1853 | A single keymap can appear as multiple menu panes, if you explicitly |
| 1854 | arrange for this. The way to do this is to make a keymap for each pane, |
| 1855 | then create a binding for each of those maps in the main keymap of the |
| 1856 | menu. Give each of these bindings an item string that starts with |
| 1857 | @samp{@@}. The rest of the item string becomes the name of the pane. |
| 1858 | See the file @file{lisp/mouse.el} for an example of this. Any ordinary |
| 1859 | bindings with @samp{@@}-less item strings are grouped into one pane, |
| 1860 | which appears along with the other panes explicitly created for the |
| 1861 | submaps. |
| 1862 | |
| 1863 | X toolkit menus don't have panes; instead, they can have submenus. |
| 1864 | Every nested keymap becomes a submenu, whether the item string starts |
| 1865 | with @samp{@@} or not. In a toolkit version of Emacs, the only thing |
| 1866 | special about @samp{@@} at the beginning of an item string is that the |
| 1867 | @samp{@@} doesn't appear in the menu item. |
| 1868 | |
| 1869 | You can also produce multiple panes or submenus from separate keymaps. |
| 1870 | The full definition of a prefix key always comes from merging the |
| 1871 | definitions supplied by the various active keymaps (minor mode, local, |
| 1872 | and global). When more than one of these keymaps is a menu, each of |
| 1873 | them makes a separate pane or panes (when Emacs does not use an |
| 1874 | X-toolkit) or a separate submenu (when using an X-toolkit). |
| 1875 | @xref{Active Keymaps}. |
| 1876 | |
| 1877 | @node Keyboard Menus |
| 1878 | @subsection Menus and the Keyboard |
| 1879 | |
| 1880 | When a prefix key ending with a keyboard event (a character or function |
| 1881 | key) has a definition that is a menu keymap, the user can use the |
| 1882 | keyboard to choose a menu item. |
| 1883 | |
| 1884 | Emacs displays the menu's overall prompt string followed by the |
| 1885 | alternatives (the item strings of the bindings) in the echo area. If |
| 1886 | the bindings don't all fit at once, the user can type @key{SPC} to see |
| 1887 | the next line of alternatives. Successive uses of @key{SPC} eventually |
| 1888 | get to the end of the menu and then cycle around to the beginning. (The |
| 1889 | variable @code{menu-prompt-more-char} specifies which character is used |
| 1890 | for this; @key{SPC} is the default.) |
| 1891 | |
| 1892 | When the user has found the desired alternative from the menu, he or she |
| 1893 | should type the corresponding character---the one whose binding is that |
| 1894 | alternative. |
| 1895 | |
| 1896 | @ignore |
| 1897 | In a menu intended for keyboard use, each menu item must clearly |
| 1898 | indicate what character to type. The best convention to use is to make |
| 1899 | the character the first letter of the item string---that is something |
| 1900 | users will understand without being told. We plan to change this; by |
| 1901 | the time you read this manual, keyboard menus may explicitly name the |
| 1902 | key for each alternative. |
| 1903 | @end ignore |
| 1904 | |
| 1905 | This way of using menus in an Emacs-like editor was inspired by the |
| 1906 | Hierarkey system. |
| 1907 | |
| 1908 | @defvar menu-prompt-more-char |
| 1909 | This variable specifies the character to use to ask to see |
| 1910 | the next line of a menu. Its initial value is 32, the code |
| 1911 | for @key{SPC}. |
| 1912 | @end defvar |
| 1913 | |
| 1914 | @node Menu Example |
| 1915 | @subsection Menu Example |
| 1916 | @cindex menu definition example |
| 1917 | |
| 1918 | Here is a complete example of defining a menu keymap. It is the |
| 1919 | definition of the @samp{Print} submenu in the @samp{Tools} menu in the |
| 1920 | menu bar, and it uses the simple menu item format (@pxref{Simple Menu |
| 1921 | Items}). First we create the keymap, and give it a name: |
| 1922 | |
| 1923 | @example |
| 1924 | (defvar menu-bar-print-menu (make-sparse-keymap "Print")) |
| 1925 | @end example |
| 1926 | |
| 1927 | @noindent |
| 1928 | Next we define the menu items: |
| 1929 | |
| 1930 | @example |
| 1931 | (define-key menu-bar-print-menu [ps-print-region] |
| 1932 | '("Postscript Print Region" . ps-print-region-with-faces)) |
| 1933 | (define-key menu-bar-print-menu [ps-print-buffer] |
| 1934 | '("Postscript Print Buffer" . ps-print-buffer-with-faces)) |
| 1935 | (define-key menu-bar-print-menu [separator-ps-print] |
| 1936 | '("--")) |
| 1937 | (define-key menu-bar-print-menu [print-region] |
| 1938 | '("Print Region" . print-region)) |
| 1939 | (define-key menu-bar-print-menu [print-buffer] |
| 1940 | '("Print Buffer" . print-buffer)) |
| 1941 | @end example |
| 1942 | |
| 1943 | @noindent |
| 1944 | Note the symbols which the bindings are ``made for''; these appear |
| 1945 | inside square brackets, in the key sequence being defined. In some |
| 1946 | cases, this symbol is the same as the command name; sometimes it is |
| 1947 | different. These symbols are treated as ``function keys'', but they are |
| 1948 | not real function keys on the keyboard. They do not affect the |
| 1949 | functioning of the menu itself, but they are ``echoed'' in the echo area |
| 1950 | when the user selects from the menu, and they appear in the output of |
| 1951 | @code{where-is} and @code{apropos}. |
| 1952 | |
| 1953 | The binding whose definition is @code{("--")} is a separator line. |
| 1954 | Like a real menu item, the separator has a key symbol, in this case |
| 1955 | @code{separator-ps-print}. If one menu has two separators, they must |
| 1956 | have two different key symbols. |
| 1957 | |
| 1958 | Here is code to define enable conditions for two of the commands in |
| 1959 | the menu: |
| 1960 | |
| 1961 | @example |
| 1962 | (put 'print-region 'menu-enable 'mark-active) |
| 1963 | (put 'ps-print-region-with-faces 'menu-enable 'mark-active) |
| 1964 | @end example |
| 1965 | |
| 1966 | Here is how we make this menu appear as an item in the parent menu: |
| 1967 | |
| 1968 | @example |
| 1969 | (define-key menu-bar-tools-menu [print] |
| 1970 | (cons "Print" menu-bar-print-menu)) |
| 1971 | @end example |
| 1972 | |
| 1973 | @noindent |
| 1974 | Note that this incorporates the submenu keymap, which is the value of |
| 1975 | the variable @code{menu-bar-print-menu}, rather than the symbol |
| 1976 | @code{menu-bar-print-menu} itself. Using that symbol in the parent menu |
| 1977 | item would be meaningless because @code{menu-bar-print-menu} is not a |
| 1978 | command. |
| 1979 | |
| 1980 | If you wanted to attach the same print menu to a mouse click, you |
| 1981 | can do it this way: |
| 1982 | |
| 1983 | @example |
| 1984 | (define-key global-map [C-S-down-mouse-1] |
| 1985 | menu-bar-print-menu) |
| 1986 | @end example |
| 1987 | |
| 1988 | We could equally well use an extended menu item (@pxref{Extended Menu |
| 1989 | Items}) for @code{print-region}, like this: |
| 1990 | |
| 1991 | @example |
| 1992 | (define-key menu-bar-print-menu [print-region] |
| 1993 | '(menu-item "Print Region" print-region |
| 1994 | :enable mark-active)) |
| 1995 | @end example |
| 1996 | |
| 1997 | @noindent |
| 1998 | With the extended menu item, the enable condition is specified |
| 1999 | inside the menu item itself. If we wanted to make this |
| 2000 | item disappear from the menu entirely when the mark is inactive, |
| 2001 | we could do it this way: |
| 2002 | |
| 2003 | @example |
| 2004 | (define-key menu-bar-print-menu [print-region] |
| 2005 | '(menu-item "Print Region" print-region |
| 2006 | :visible mark-active)) |
| 2007 | @end example |
| 2008 | |
| 2009 | @node Menu Bar |
| 2010 | @subsection The Menu Bar |
| 2011 | @cindex menu bar |
| 2012 | |
| 2013 | Most window systems allow each frame to have a @dfn{menu bar}---a |
| 2014 | permanently displayed menu stretching horizontally across the top of the |
| 2015 | frame. The items of the menu bar are the subcommands of the fake |
| 2016 | ``function key'' @code{menu-bar}, as defined by all the active keymaps. |
| 2017 | |
| 2018 | To add an item to the menu bar, invent a fake ``function key'' of your |
| 2019 | own (let's call it @var{key}), and make a binding for the key sequence |
| 2020 | @code{[menu-bar @var{key}]}. Most often, the binding is a menu keymap, |
| 2021 | so that pressing a button on the menu bar item leads to another menu. |
| 2022 | |
| 2023 | When more than one active keymap defines the same fake function key |
| 2024 | for the menu bar, the item appears just once. If the user clicks on |
| 2025 | that menu bar item, it brings up a single, combined menu containing |
| 2026 | all the subcommands of that item---the global subcommands, the local |
| 2027 | subcommands, and the minor mode subcommands. |
| 2028 | |
| 2029 | The variable @code{overriding-local-map} is normally ignored when |
| 2030 | determining the menu bar contents. That is, the menu bar is computed |
| 2031 | from the keymaps that would be active if @code{overriding-local-map} |
| 2032 | were @code{nil}. @xref{Active Keymaps}. |
| 2033 | |
| 2034 | In order for a frame to display a menu bar, its @code{menu-bar-lines} |
| 2035 | parameter must be greater than zero. Emacs uses just one line for the |
| 2036 | menu bar itself; if you specify more than one line, the other lines |
| 2037 | serve to separate the menu bar from the windows in the frame. We |
| 2038 | recommend 1 or 2 as the value of @code{menu-bar-lines}. @xref{Window Frame |
| 2039 | Parameters}. |
| 2040 | |
| 2041 | Here's an example of setting up a menu bar item: |
| 2042 | |
| 2043 | @example |
| 2044 | @group |
| 2045 | (modify-frame-parameters (selected-frame) |
| 2046 | '((menu-bar-lines . 2))) |
| 2047 | @end group |
| 2048 | |
| 2049 | @group |
| 2050 | ;; @r{Make a menu keymap (with a prompt string)} |
| 2051 | ;; @r{and make it the menu bar item's definition.} |
| 2052 | (define-key global-map [menu-bar words] |
| 2053 | (cons "Words" (make-sparse-keymap "Words"))) |
| 2054 | @end group |
| 2055 | |
| 2056 | @group |
| 2057 | ;; @r{Define specific subcommands in this menu.} |
| 2058 | (define-key global-map |
| 2059 | [menu-bar words forward] |
| 2060 | '("Forward word" . forward-word)) |
| 2061 | @end group |
| 2062 | @group |
| 2063 | (define-key global-map |
| 2064 | [menu-bar words backward] |
| 2065 | '("Backward word" . backward-word)) |
| 2066 | @end group |
| 2067 | @end example |
| 2068 | |
| 2069 | A local keymap can cancel a menu bar item made by the global keymap by |
| 2070 | rebinding the same fake function key with @code{undefined} as the |
| 2071 | binding. For example, this is how Dired suppresses the @samp{Edit} menu |
| 2072 | bar item: |
| 2073 | |
| 2074 | @example |
| 2075 | (define-key dired-mode-map [menu-bar edit] 'undefined) |
| 2076 | @end example |
| 2077 | |
| 2078 | @noindent |
| 2079 | @code{edit} is the fake function key used by the global map for the |
| 2080 | @samp{Edit} menu bar item. The main reason to suppress a global |
| 2081 | menu bar item is to regain space for mode-specific items. |
| 2082 | |
| 2083 | @defvar menu-bar-final-items |
| 2084 | Normally the menu bar shows global items followed by items defined by the |
| 2085 | local maps. |
| 2086 | |
| 2087 | This variable holds a list of fake function keys for items to display at |
| 2088 | the end of the menu bar rather than in normal sequence. The default |
| 2089 | value is @code{(help-menu)}; thus, the @samp{Help} menu item normally appears |
| 2090 | at the end of the menu bar, following local menu items. |
| 2091 | @end defvar |
| 2092 | |
| 2093 | @defvar menu-bar-update-hook |
| 2094 | This normal hook is run whenever the user clicks on the menu bar, before |
| 2095 | displaying a submenu. You can use it to update submenus whose contents |
| 2096 | should vary. |
| 2097 | @end defvar |
| 2098 | |
| 2099 | @node Tool Bar |
| 2100 | @subsection Tool bars |
| 2101 | @cindex tool bar |
| 2102 | |
| 2103 | A @dfn{tool bar} is a row of icons at the top of a frame, that execute |
| 2104 | commands when you click on them---in effect, a kind of graphical menu |
| 2105 | bar. Emacs supports tool bars starting with version 21. |
| 2106 | |
| 2107 | The frame parameter @code{tool-bar-lines} (X resource @samp{toolBar}) |
| 2108 | controls how many lines' worth of height to reserve for the tool bar. A |
| 2109 | zero value suppresses the tool bar. If the value is nonzero, and |
| 2110 | @code{auto-resize-tool-bars} is non-@code{nil}, the tool bar expands and |
| 2111 | contracts automatically as needed to hold the specified contents. |
| 2112 | |
| 2113 | The tool bar contents are controlled by a menu keymap attached to a |
| 2114 | fake ``function key'' called @code{tool-bar} (much like the way the menu |
| 2115 | bar is controlled). So you define a tool bar item using |
| 2116 | @code{define-key}, like this: |
| 2117 | |
| 2118 | @example |
| 2119 | (define-key global-map [tool-bar @var{key}] @var{item}) |
| 2120 | @end example |
| 2121 | |
| 2122 | @noindent |
| 2123 | where @var{key} is a fake ``function key'' to distinguish this item from |
| 2124 | other items, and @var{item} is a menu item key binding (@pxref{Extended |
| 2125 | Menu Items}), which says how to display this item and how it behaves. |
| 2126 | |
| 2127 | The usual menu keymap item properties, @code{:visible}, |
| 2128 | @code{:enable}, @code{:button}, and @code{:filter}, are useful in |
| 2129 | tool bar bindings and have their normal meanings. The @var{real-binding} |
| 2130 | in the item must be a command, not a keymap; in other words, it does not |
| 2131 | work to define a tool bar icon as a prefix key. |
| 2132 | |
| 2133 | The @code{:help} property specifies a ``help-echo'' string to display |
| 2134 | while the mouse is on that item. This is displayed in the same way as |
| 2135 | @code{help-echo} text properties (@pxref{Help display}). |
| 2136 | |
| 2137 | In addition, you should use the @code{:image} property; |
| 2138 | this is how you specify the image to display in the tool bar: |
| 2139 | |
| 2140 | @table @code |
| 2141 | @item :image @var{image} |
| 2142 | @var{images} is either a single image specification or a vector of four |
| 2143 | image specifications. If you use a vector of four, |
| 2144 | one of them is used, depending on circumstances: |
| 2145 | |
| 2146 | @table @asis |
| 2147 | @item item 0 |
| 2148 | Used when the item is enabled and selected. |
| 2149 | @item item 1 |
| 2150 | Used when the item is enabled and deselected. |
| 2151 | @item item 2 |
| 2152 | Used when the item is disabled and selected. |
| 2153 | @item item 3 |
| 2154 | Used when the item is disabled and deselected. |
| 2155 | @end table |
| 2156 | @end table |
| 2157 | |
| 2158 | If @var{image} is a single image specification, Emacs draws the tool bar |
| 2159 | button in disabled state by applying an edge-detection algorithm to the |
| 2160 | image. |
| 2161 | |
| 2162 | @tindex auto-resize-tool-bar |
| 2163 | @defvar auto-resize-tool-bar |
| 2164 | If this variable is non-@code{nil}, the tool bar automatically resizes to |
| 2165 | show all defined tool bar items---but not larger than a quarter of the |
| 2166 | frame's height. |
| 2167 | @end defvar |
| 2168 | |
| 2169 | @tindex auto-raise-tool-bar-items |
| 2170 | @defvar auto-raise-tool-bar-items |
| 2171 | If this variable is non-@code{nil}, tool bar items display |
| 2172 | in raised form when the mouse moves over them. |
| 2173 | @end defvar |
| 2174 | |
| 2175 | @tindex tool-bar-item-margin |
| 2176 | @defvar tool-bar-item-margin |
| 2177 | This variable specifies an extra margin to add around tool bar items. |
| 2178 | The value is an integer, a number of pixels. The default is 1. |
| 2179 | @end defvar |
| 2180 | |
| 2181 | @tindex tool-bar-item-relief |
| 2182 | @defvar tool-bar-item-relief |
| 2183 | This variable specifies the shadow width for tool bar items. |
| 2184 | The value is an integer, a number of pixels. The default is 3. |
| 2185 | @end defvar |
| 2186 | |
| 2187 | You can define a special meaning for clicking on a tool bar item with |
| 2188 | the shift, control, meta, etc., modifiers. You do this by setting up |
| 2189 | additional items that relate to the original item through the fake |
| 2190 | function keys. Specifically, the additional items should use the |
| 2191 | modified versions of the same fake function key used to name the |
| 2192 | original item. |
| 2193 | |
| 2194 | Thus, if the original item was defined this way, |
| 2195 | |
| 2196 | @example |
| 2197 | (define-key global-map [tool-bar shell] |
| 2198 | '(menu-item "Shell" shell |
| 2199 | :image (image :type xpm :file "shell.xpm"))) |
| 2200 | @end example |
| 2201 | |
| 2202 | @noindent |
| 2203 | then here is how you can define clicking on the same tool bar image with |
| 2204 | the shift modifier: |
| 2205 | |
| 2206 | @example |
| 2207 | (define-key global-map [tool-bar S-shell] 'some-command) |
| 2208 | @end example |
| 2209 | |
| 2210 | @xref{Function Keys}, for more information about how to add modifiers to |
| 2211 | function keys. |
| 2212 | |
| 2213 | @node Modifying Menus |
| 2214 | @subsection Modifying Menus |
| 2215 | |
| 2216 | When you insert a new item in an existing menu, you probably want to |
| 2217 | put it in a particular place among the menu's existing items. If you |
| 2218 | use @code{define-key} to add the item, it normally goes at the front of |
| 2219 | the menu. To put it elsewhere in the menu, use @code{define-key-after}: |
| 2220 | |
| 2221 | @defun define-key-after map key binding &optional after |
| 2222 | Define a binding in @var{map} for @var{key}, with value @var{binding}, |
| 2223 | just like @code{define-key}, but position the binding in @var{map} after |
| 2224 | the binding for the event @var{after}. The argument @var{key} should be |
| 2225 | of length one---a vector or string with just one element. But |
| 2226 | @var{after} should be a single event type---a symbol or a character, not |
| 2227 | a sequence. The new binding goes after the binding for @var{after}. If |
| 2228 | @var{after} is @code{t} or is omitted, then the new binding goes last, at |
| 2229 | the end of the keymap. However, new bindings are added before any |
| 2230 | inherited keymap. |
| 2231 | |
| 2232 | Here is an example: |
| 2233 | |
| 2234 | @example |
| 2235 | (define-key-after my-menu [drink] |
| 2236 | '("Drink" . drink-command) 'eat) |
| 2237 | @end example |
| 2238 | |
| 2239 | @noindent |
| 2240 | makes a binding for the fake function key @key{DRINK} and puts it |
| 2241 | right after the binding for @key{EAT}. |
| 2242 | |
| 2243 | Here is how to insert an item called @samp{Work} in the @samp{Signals} |
| 2244 | menu of Shell mode, after the item @code{break}: |
| 2245 | |
| 2246 | @example |
| 2247 | (define-key-after |
| 2248 | (lookup-key shell-mode-map [menu-bar signals]) |
| 2249 | [work] '("Work" . work-command) 'break) |
| 2250 | @end example |
| 2251 | @end defun |