| 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, 2001, |
| 4 | @c 2002, 2003, 2004, 2005, 2006, 2007 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 command bindings of input events are recorded in data structures |
| 12 | called @dfn{keymaps}. Each entry in a keymap associates (or |
| 13 | @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 |
| 15 | used to look up the next input event; this continues until a command |
| 16 | is found. The whole process is called @dfn{key lookup}. |
| 17 | |
| 18 | @menu |
| 19 | * Key Sequences:: Key sequences as Lisp objects. |
| 20 | * Keymap Basics:: Basic concepts of keymaps. |
| 21 | * Format of Keymaps:: What a keymap looks like as a Lisp object. |
| 22 | * Creating Keymaps:: Functions to create and copy keymaps. |
| 23 | * Inheritance and Keymaps:: How one keymap can inherit the bindings |
| 24 | of another keymap. |
| 25 | * Prefix Keys:: Defining a key with a keymap as its definition. |
| 26 | * Active Keymaps:: How Emacs searches the active keymaps |
| 27 | for a key binding. |
| 28 | * Searching Keymaps:: A pseudo-Lisp summary of searching active maps. |
| 29 | * Controlling Active Maps:: Each buffer has a local keymap |
| 30 | to override the standard (global) bindings. |
| 31 | A minor mode can also override them. |
| 32 | * Key Lookup:: Finding a key's binding in one keymap. |
| 33 | * Functions for Key Lookup:: How to request key lookup. |
| 34 | * Changing Key Bindings:: Redefining a key in a keymap. |
| 35 | * Remapping Commands:: A keymap can translate one command to another. |
| 36 | * Translation Keymaps:: Keymaps for translating sequences of events. |
| 37 | * Key Binding Commands:: Interactive interfaces for redefining keys. |
| 38 | * Scanning Keymaps:: Looking through all keymaps, for printing help. |
| 39 | * Menu Keymaps:: Defining a menu as a keymap. |
| 40 | @end menu |
| 41 | |
| 42 | @node Key Sequences |
| 43 | @section Key Sequences |
| 44 | @cindex key |
| 45 | @cindex keystroke |
| 46 | @cindex key sequence |
| 47 | |
| 48 | A @dfn{key sequence}, or @dfn{key} for short, is a sequence of one |
| 49 | or more input events that form a unit. Input events include |
| 50 | characters, function keys, and mouse actions (@pxref{Input Events}). |
| 51 | The Emacs Lisp representation for a key sequence is a string or |
| 52 | vector. Unless otherwise stated, any Emacs Lisp function that accepts |
| 53 | a key sequence as an argument can handle both representations. |
| 54 | |
| 55 | In the string representation, alphanumeric characters ordinarily |
| 56 | stand for themselves; for example, @code{"a"} represents @kbd{a} |
| 57 | and @code{"2"} represents @kbd{2}. Control character events are |
| 58 | prefixed by the substring @code{"\C-"}, and meta characters by |
| 59 | @code{"\M-"}; for example, @code{"\C-x"} represents the key @kbd{C-x}. |
| 60 | In addition, the @key{TAB}, @key{RET}, @key{ESC}, and @key{DEL} events |
| 61 | are represented by @code{"\t"}, @code{"\r"}, @code{"\e"}, and |
| 62 | @code{"\d"} respectively. The string representation of a complete key |
| 63 | sequence is the concatenation of the string representations of the |
| 64 | constituent events; thus, @code{"\C-xl"} represents the key sequence |
| 65 | @kbd{C-x l}. |
| 66 | |
| 67 | Key sequences containing function keys, mouse button events, or |
| 68 | non-ASCII characters such as @kbd{C-=} or @kbd{H-a} cannot be |
| 69 | represented as strings; they have to be represented as vectors. |
| 70 | |
| 71 | In the vector representation, each element of the vector represents |
| 72 | an input event, in its Lisp form. @xref{Input Events}. For example, |
| 73 | the vector @code{[?\C-x ?l]} represents the key sequence @kbd{C-x l}. |
| 74 | |
| 75 | For examples of key sequences written in string and vector |
| 76 | representations, @ref{Init Rebinding,,, emacs, The GNU Emacs Manual}. |
| 77 | |
| 78 | @defmac kbd keyseq-text |
| 79 | This macro converts the text @var{keyseq-text} (a string constant) |
| 80 | into a key sequence (a string or vector constant). The contents of |
| 81 | @var{keyseq-text} should describe the key sequence using almost the same |
| 82 | syntax used in this manual. More precisely, it uses the same syntax |
| 83 | that Edit Macro mode uses for editing keyboard macros (@pxref{Edit |
| 84 | Keyboard Macro,,, emacs, The GNU Emacs Manual}); you must surround |
| 85 | function key names with @samp{<@dots{}>}. |
| 86 | |
| 87 | @example |
| 88 | (kbd "C-x") @result{} "\C-x" |
| 89 | (kbd "C-x C-f") @result{} "\C-x\C-f" |
| 90 | (kbd "C-x 4 C-f") @result{} "\C-x4\C-f" |
| 91 | (kbd "X") @result{} "X" |
| 92 | (kbd "RET") @result{} "\^M" |
| 93 | (kbd "C-c SPC") @result{} "\C-c@ " |
| 94 | (kbd "<f1> SPC") @result{} [f1 32] |
| 95 | (kbd "C-M-<down>") @result{} [C-M-down] |
| 96 | @end example |
| 97 | |
| 98 | This macro is not meant for use with arguments that vary---only |
| 99 | with string constants. |
| 100 | @end defmac |
| 101 | |
| 102 | @node Keymap Basics |
| 103 | @section Keymap Basics |
| 104 | @cindex key binding |
| 105 | @cindex binding of a key |
| 106 | @cindex complete key |
| 107 | @cindex undefined key |
| 108 | |
| 109 | A keymap is a Lisp data structure that specifies @dfn{key bindings} |
| 110 | for various key sequences. |
| 111 | |
| 112 | A single keymap directly specifies definitions for individual |
| 113 | events. When a key sequence consists of a single event, its binding |
| 114 | in a keymap is the keymap's definition for that event. The binding of |
| 115 | a longer key sequence is found by an iterative process: first find the |
| 116 | definition of the first event (which must itself be a keymap); then |
| 117 | find the second event's definition in that keymap, and so on until all |
| 118 | the events in the key sequence have been processed. |
| 119 | |
| 120 | If the binding of a key sequence is a keymap, we call the key sequence |
| 121 | a @dfn{prefix key}. Otherwise, we call it a @dfn{complete key} (because |
| 122 | no more events can be added to it). If the binding is @code{nil}, |
| 123 | we call the key @dfn{undefined}. Examples of prefix keys are @kbd{C-c}, |
| 124 | @kbd{C-x}, and @kbd{C-x 4}. Examples of defined complete keys are |
| 125 | @kbd{X}, @key{RET}, and @kbd{C-x 4 C-f}. Examples of undefined complete |
| 126 | keys are @kbd{C-x C-g}, and @kbd{C-c 3}. @xref{Prefix Keys}, for more |
| 127 | details. |
| 128 | |
| 129 | The rule for finding the binding of a key sequence assumes that the |
| 130 | intermediate bindings (found for the events before the last) are all |
| 131 | keymaps; if this is not so, the sequence of events does not form a |
| 132 | unit---it is not really one key sequence. In other words, removing one |
| 133 | or more events from the end of any valid key sequence must always yield |
| 134 | a prefix key. For example, @kbd{C-f C-n} is not a key sequence; |
| 135 | @kbd{C-f} is not a prefix key, so a longer sequence starting with |
| 136 | @kbd{C-f} cannot be a key sequence. |
| 137 | |
| 138 | The set of possible multi-event key sequences depends on the bindings |
| 139 | for prefix keys; therefore, it can be different for different keymaps, |
| 140 | and can change when bindings are changed. However, a one-event sequence |
| 141 | is always a key sequence, because it does not depend on any prefix keys |
| 142 | for its well-formedness. |
| 143 | |
| 144 | At any time, several primary keymaps are @dfn{active}---that is, in |
| 145 | use for finding key bindings. These are the @dfn{global map}, which is |
| 146 | shared by all buffers; the @dfn{local keymap}, which is usually |
| 147 | associated with a specific major mode; and zero or more @dfn{minor mode |
| 148 | keymaps}, which belong to currently enabled minor modes. (Not all minor |
| 149 | modes have keymaps.) The local keymap bindings shadow (i.e., take |
| 150 | precedence over) the corresponding global bindings. The minor mode |
| 151 | keymaps shadow both local and global keymaps. @xref{Active Keymaps}, |
| 152 | for details. |
| 153 | |
| 154 | @node Format of Keymaps |
| 155 | @section Format of Keymaps |
| 156 | @cindex format of keymaps |
| 157 | @cindex keymap format |
| 158 | @cindex full keymap |
| 159 | @cindex sparse keymap |
| 160 | |
| 161 | Each keymap is a list whose @sc{car} is the symbol @code{keymap}. The |
| 162 | remaining elements of the list define the key bindings of the keymap. |
| 163 | A symbol whose function definition is a keymap is also a keymap. Use |
| 164 | the function @code{keymapp} (see below) to test whether an object is a |
| 165 | keymap. |
| 166 | |
| 167 | Several kinds of elements may appear in a keymap, after the symbol |
| 168 | @code{keymap} that begins it: |
| 169 | |
| 170 | @table @code |
| 171 | @item (@var{type} .@: @var{binding}) |
| 172 | This specifies one binding, for events of type @var{type}. Each |
| 173 | ordinary binding applies to events of a particular @dfn{event type}, |
| 174 | which is always a character or a symbol. @xref{Classifying Events}. |
| 175 | In this kind of binding, @var{binding} is a command. |
| 176 | |
| 177 | @item (@var{type} @var{item-name} @r{[}@var{cache}@r{]} .@: @var{binding}) |
| 178 | This specifies a binding which is also a simple menu item that |
| 179 | displays as @var{item-name} in the menu. @var{cache}, if present, |
| 180 | caches certain information for display in the menu. @xref{Simple Menu |
| 181 | Items}. |
| 182 | |
| 183 | @item (@var{type} @var{item-name} @var{help-string} @r{[}@var{cache}@r{]} .@: @var{binding}) |
| 184 | This is a simple menu item with help string @var{help-string}. |
| 185 | |
| 186 | @item (@var{type} menu-item .@: @var{details}) |
| 187 | This specifies a binding which is also an extended menu item. This |
| 188 | allows use of other features. @xref{Extended Menu Items}. |
| 189 | |
| 190 | @item (t .@: @var{binding}) |
| 191 | @cindex default key binding |
| 192 | This specifies a @dfn{default key binding}; any event not bound by other |
| 193 | elements of the keymap is given @var{binding} as its binding. Default |
| 194 | bindings allow a keymap to bind all possible event types without having |
| 195 | to enumerate all of them. A keymap that has a default binding |
| 196 | completely masks any lower-precedence keymap, except for events |
| 197 | explicitly bound to @code{nil} (see below). |
| 198 | |
| 199 | @item @var{char-table} |
| 200 | If an element of a keymap is a char-table, it counts as holding |
| 201 | bindings for all character events with no modifier bits |
| 202 | (@pxref{modifier bits}): element @var{n} is the binding for the |
| 203 | character with code @var{n}. This is a compact way to record lots of |
| 204 | bindings. A keymap with such a char-table is called a @dfn{full |
| 205 | keymap}. Other keymaps are called @dfn{sparse keymaps}. |
| 206 | |
| 207 | @item @var{string} |
| 208 | @cindex keymap prompt string |
| 209 | @cindex overall prompt string |
| 210 | @cindex prompt string of keymap |
| 211 | Aside from elements that specify bindings for keys, a keymap can also |
| 212 | have a string as an element. This is called the @dfn{overall prompt |
| 213 | string} and makes it possible to use the keymap as a menu. |
| 214 | @xref{Defining Menus}. |
| 215 | @end table |
| 216 | |
| 217 | When the binding is @code{nil}, it doesn't constitute a definition |
| 218 | but it does take precedence over a default binding or a binding in the |
| 219 | parent keymap. On the other hand, a binding of @code{nil} does |
| 220 | @emph{not} override lower-precedence keymaps; thus, if the local map |
| 221 | gives a binding of @code{nil}, Emacs uses the binding from the |
| 222 | global map. |
| 223 | |
| 224 | @cindex meta characters lookup |
| 225 | Keymaps do not directly record bindings for the meta characters. |
| 226 | Instead, meta characters are regarded for purposes of key lookup as |
| 227 | sequences of two characters, the first of which is @key{ESC} (or |
| 228 | whatever is currently the value of @code{meta-prefix-char}). Thus, the |
| 229 | key @kbd{M-a} is internally represented as @kbd{@key{ESC} a}, and its |
| 230 | global binding is found at the slot for @kbd{a} in @code{esc-map} |
| 231 | (@pxref{Prefix Keys}). |
| 232 | |
| 233 | This conversion applies only to characters, not to function keys or |
| 234 | other input events; thus, @kbd{M-@key{end}} has nothing to do with |
| 235 | @kbd{@key{ESC} @key{end}}. |
| 236 | |
| 237 | Here as an example is the local keymap for Lisp mode, a sparse |
| 238 | keymap. It defines bindings for @key{DEL} and @key{TAB}, plus @kbd{C-c |
| 239 | C-l}, @kbd{M-C-q}, and @kbd{M-C-x}. |
| 240 | |
| 241 | @example |
| 242 | @group |
| 243 | lisp-mode-map |
| 244 | @result{} |
| 245 | @end group |
| 246 | @group |
| 247 | (keymap |
| 248 | (3 keymap |
| 249 | ;; @kbd{C-c C-z} |
| 250 | (26 . run-lisp)) |
| 251 | @end group |
| 252 | @group |
| 253 | (27 keymap |
| 254 | ;; @r{@kbd{M-C-x}, treated as @kbd{@key{ESC} C-x}} |
| 255 | (24 . lisp-send-defun) |
| 256 | keymap |
| 257 | ;; @r{@kbd{M-C-q}, treated as @kbd{@key{ESC} C-q}} |
| 258 | (17 . indent-sexp)) |
| 259 | @end group |
| 260 | @group |
| 261 | ;; @r{This part is inherited from @code{lisp-mode-shared-map}.} |
| 262 | keymap |
| 263 | ;; @key{DEL} |
| 264 | (127 . backward-delete-char-untabify) |
| 265 | @end group |
| 266 | @group |
| 267 | (27 keymap |
| 268 | ;; @r{@kbd{M-C-q}, treated as @kbd{@key{ESC} C-q}} |
| 269 | (17 . indent-sexp)) |
| 270 | (9 . lisp-indent-line)) |
| 271 | @end group |
| 272 | @end example |
| 273 | |
| 274 | @defun keymapp object |
| 275 | This function returns @code{t} if @var{object} is a keymap, @code{nil} |
| 276 | otherwise. More precisely, this function tests for a list whose |
| 277 | @sc{car} is @code{keymap}, or for a symbol whose function definition |
| 278 | satisfies @code{keymapp}. |
| 279 | |
| 280 | @example |
| 281 | @group |
| 282 | (keymapp '(keymap)) |
| 283 | @result{} t |
| 284 | @end group |
| 285 | @group |
| 286 | (fset 'foo '(keymap)) |
| 287 | (keymapp 'foo) |
| 288 | @result{} t |
| 289 | @end group |
| 290 | @group |
| 291 | (keymapp (current-global-map)) |
| 292 | @result{} t |
| 293 | @end group |
| 294 | @end example |
| 295 | @end defun |
| 296 | |
| 297 | @node Creating Keymaps |
| 298 | @section Creating Keymaps |
| 299 | @cindex creating keymaps |
| 300 | |
| 301 | Here we describe the functions for creating keymaps. |
| 302 | |
| 303 | @defun make-sparse-keymap &optional prompt |
| 304 | This function creates and returns a new sparse keymap with no entries. |
| 305 | (A sparse keymap is the kind of keymap you usually want.) The new |
| 306 | keymap does not contain a char-table, unlike @code{make-keymap}, and |
| 307 | does not bind any events. |
| 308 | |
| 309 | @example |
| 310 | @group |
| 311 | (make-sparse-keymap) |
| 312 | @result{} (keymap) |
| 313 | @end group |
| 314 | @end example |
| 315 | |
| 316 | If you specify @var{prompt}, that becomes the overall prompt string |
| 317 | for the keymap. You should specify this only for menu keymaps |
| 318 | (@pxref{Defining Menus}). A keymap with an overall prompt string will |
| 319 | always present a mouse menu or a keyboard menu if it is active for |
| 320 | looking up the next input event. Don't specify an overall prompt string |
| 321 | for the main map of a major or minor mode, because that would cause |
| 322 | the command loop to present a keyboard menu every time. |
| 323 | @end defun |
| 324 | |
| 325 | @defun make-keymap &optional prompt |
| 326 | This function creates and returns a new full keymap. That keymap |
| 327 | contains a char-table (@pxref{Char-Tables}) with slots for all |
| 328 | characters without modifiers. The new keymap initially binds all |
| 329 | these characters to @code{nil}, and does not bind any other kind of |
| 330 | event. The argument @var{prompt} specifies a |
| 331 | prompt string, as in @code{make-sparse-keymap}. |
| 332 | |
| 333 | @example |
| 334 | @group |
| 335 | (make-keymap) |
| 336 | @result{} (keymap #^[t nil nil nil @dots{} nil nil keymap]) |
| 337 | @end group |
| 338 | @end example |
| 339 | |
| 340 | A full keymap is more efficient than a sparse keymap when it holds |
| 341 | lots of bindings; for just a few, the sparse keymap is better. |
| 342 | @end defun |
| 343 | |
| 344 | @defun copy-keymap keymap |
| 345 | This function returns a copy of @var{keymap}. Any keymaps that |
| 346 | appear directly as bindings in @var{keymap} are also copied recursively, |
| 347 | and so on to any number of levels. However, recursive copying does not |
| 348 | take place when the definition of a character is a symbol whose function |
| 349 | definition is a keymap; the same symbol appears in the new copy. |
| 350 | @c Emacs 19 feature |
| 351 | |
| 352 | @example |
| 353 | @group |
| 354 | (setq map (copy-keymap (current-local-map))) |
| 355 | @result{} (keymap |
| 356 | @end group |
| 357 | @group |
| 358 | ;; @r{(This implements meta characters.)} |
| 359 | (27 keymap |
| 360 | (83 . center-paragraph) |
| 361 | (115 . center-line)) |
| 362 | (9 . tab-to-tab-stop)) |
| 363 | @end group |
| 364 | |
| 365 | @group |
| 366 | (eq map (current-local-map)) |
| 367 | @result{} nil |
| 368 | @end group |
| 369 | @group |
| 370 | (equal map (current-local-map)) |
| 371 | @result{} t |
| 372 | @end group |
| 373 | @end example |
| 374 | @end defun |
| 375 | |
| 376 | @node Inheritance and Keymaps |
| 377 | @section Inheritance and Keymaps |
| 378 | @cindex keymap inheritance |
| 379 | @cindex inheriting a keymap's bindings |
| 380 | |
| 381 | A keymap can inherit the bindings of another keymap, which we call the |
| 382 | @dfn{parent keymap}. Such a keymap looks like this: |
| 383 | |
| 384 | @example |
| 385 | (keymap @var{elements}@dots{} . @var{parent-keymap}) |
| 386 | @end example |
| 387 | |
| 388 | @noindent |
| 389 | The effect is that this keymap inherits all the bindings of |
| 390 | @var{parent-keymap}, whatever they may be at the time a key is looked up, |
| 391 | but can add to them or override them with @var{elements}. |
| 392 | |
| 393 | If you change the bindings in @var{parent-keymap} using |
| 394 | @code{define-key} or other key-binding functions, these changed |
| 395 | bindings are visible in the inheriting keymap, unless shadowed by the |
| 396 | bindings made by @var{elements}. The converse is not true: if you use |
| 397 | @code{define-key} to change bindings in the inheriting keymap, these |
| 398 | changes are recorded in @var{elements}, but have no effect on |
| 399 | @var{parent-keymap}. |
| 400 | |
| 401 | The proper way to construct a keymap with a parent is to use |
| 402 | @code{set-keymap-parent}; if you have code that directly constructs a |
| 403 | keymap with a parent, please convert the program to use |
| 404 | @code{set-keymap-parent} instead. |
| 405 | |
| 406 | @defun keymap-parent keymap |
| 407 | This returns the parent keymap of @var{keymap}. If @var{keymap} |
| 408 | has no parent, @code{keymap-parent} returns @code{nil}. |
| 409 | @end defun |
| 410 | |
| 411 | @defun set-keymap-parent keymap parent |
| 412 | This sets the parent keymap of @var{keymap} to @var{parent}, and returns |
| 413 | @var{parent}. If @var{parent} is @code{nil}, this function gives |
| 414 | @var{keymap} no parent at all. |
| 415 | |
| 416 | If @var{keymap} has submaps (bindings for prefix keys), they too receive |
| 417 | new parent keymaps that reflect what @var{parent} specifies for those |
| 418 | prefix keys. |
| 419 | @end defun |
| 420 | |
| 421 | Here is an example showing how to make a keymap that inherits |
| 422 | from @code{text-mode-map}: |
| 423 | |
| 424 | @example |
| 425 | (let ((map (make-sparse-keymap))) |
| 426 | (set-keymap-parent map text-mode-map) |
| 427 | map) |
| 428 | @end example |
| 429 | |
| 430 | A non-sparse keymap can have a parent too, but this is not very |
| 431 | useful. A non-sparse keymap always specifies something as the binding |
| 432 | for every numeric character code without modifier bits, even if it is |
| 433 | @code{nil}, so these character's bindings are never inherited from |
| 434 | the parent keymap. |
| 435 | |
| 436 | @node Prefix Keys |
| 437 | @section Prefix Keys |
| 438 | @cindex prefix key |
| 439 | |
| 440 | A @dfn{prefix key} is a key sequence whose binding is a keymap. The |
| 441 | keymap defines what to do with key sequences that extend the prefix key. |
| 442 | For example, @kbd{C-x} is a prefix key, and it uses a keymap that is |
| 443 | also stored in the variable @code{ctl-x-map}. This keymap defines |
| 444 | bindings for key sequences starting with @kbd{C-x}. |
| 445 | |
| 446 | Some of the standard Emacs prefix keys use keymaps that are |
| 447 | also found in Lisp variables: |
| 448 | |
| 449 | @itemize @bullet |
| 450 | @item |
| 451 | @vindex esc-map |
| 452 | @findex ESC-prefix |
| 453 | @code{esc-map} is the global keymap for the @key{ESC} prefix key. Thus, |
| 454 | the global definitions of all meta characters are actually found here. |
| 455 | This map is also the function definition of @code{ESC-prefix}. |
| 456 | |
| 457 | @item |
| 458 | @cindex @kbd{C-h} |
| 459 | @code{help-map} is the global keymap for the @kbd{C-h} prefix key. |
| 460 | |
| 461 | @item |
| 462 | @cindex @kbd{C-c} |
| 463 | @vindex mode-specific-map |
| 464 | @code{mode-specific-map} is the global keymap for the prefix key |
| 465 | @kbd{C-c}. This map is actually global, not mode-specific, but its name |
| 466 | provides useful information about @kbd{C-c} in the output of @kbd{C-h b} |
| 467 | (@code{display-bindings}), since the main use of this prefix key is for |
| 468 | mode-specific bindings. |
| 469 | |
| 470 | @item |
| 471 | @cindex @kbd{C-x} |
| 472 | @vindex ctl-x-map |
| 473 | @findex Control-X-prefix |
| 474 | @code{ctl-x-map} is the global keymap used for the @kbd{C-x} prefix key. |
| 475 | This map is found via the function cell of the symbol |
| 476 | @code{Control-X-prefix}. |
| 477 | |
| 478 | @item |
| 479 | @cindex @kbd{C-x @key{RET}} |
| 480 | @vindex mule-keymap |
| 481 | @code{mule-keymap} is the global keymap used for the @kbd{C-x @key{RET}} |
| 482 | prefix key. |
| 483 | |
| 484 | @item |
| 485 | @cindex @kbd{C-x 4} |
| 486 | @vindex ctl-x-4-map |
| 487 | @code{ctl-x-4-map} is the global keymap used for the @kbd{C-x 4} prefix |
| 488 | key. |
| 489 | |
| 490 | @c Emacs 19 feature |
| 491 | @item |
| 492 | @cindex @kbd{C-x 5} |
| 493 | @vindex ctl-x-5-map |
| 494 | @code{ctl-x-5-map} is the global keymap used for the @kbd{C-x 5} prefix |
| 495 | key. |
| 496 | |
| 497 | @c Emacs 19 feature |
| 498 | @item |
| 499 | @cindex @kbd{C-x 6} |
| 500 | @vindex 2C-mode-map |
| 501 | @code{2C-mode-map} is the global keymap used for the @kbd{C-x 6} prefix |
| 502 | key. |
| 503 | |
| 504 | @item |
| 505 | @cindex @kbd{C-x v} |
| 506 | @vindex vc-prefix-map |
| 507 | @code{vc-prefix-map} is the global keymap used for the @kbd{C-x v} prefix |
| 508 | key. |
| 509 | |
| 510 | @item |
| 511 | @cindex @kbd{M-o} |
| 512 | @vindex facemenu-keymap |
| 513 | @code{facemenu-keymap} is the global keymap used for the @kbd{M-o} |
| 514 | prefix key. |
| 515 | |
| 516 | @c Emacs 19 feature |
| 517 | @item |
| 518 | The other Emacs prefix keys are @kbd{M-g}, @kbd{C-x @@}, @kbd{C-x a i}, |
| 519 | @kbd{C-x @key{ESC}} and @kbd{@key{ESC} @key{ESC}}. They use keymaps |
| 520 | that have no special names. |
| 521 | @end itemize |
| 522 | |
| 523 | The keymap binding of a prefix key is used for looking up the event |
| 524 | that follows the prefix key. (It may instead be a symbol whose function |
| 525 | definition is a keymap. The effect is the same, but the symbol serves |
| 526 | as a name for the prefix key.) Thus, the binding of @kbd{C-x} is the |
| 527 | symbol @code{Control-X-prefix}, whose function cell holds the keymap |
| 528 | for @kbd{C-x} commands. (The same keymap is also the value of |
| 529 | @code{ctl-x-map}.) |
| 530 | |
| 531 | Prefix key definitions can appear in any active keymap. The |
| 532 | definitions of @kbd{C-c}, @kbd{C-x}, @kbd{C-h} and @key{ESC} as prefix |
| 533 | keys appear in the global map, so these prefix keys are always |
| 534 | available. Major and minor modes can redefine a key as a prefix by |
| 535 | putting a prefix key definition for it in the local map or the minor |
| 536 | mode's map. @xref{Active Keymaps}. |
| 537 | |
| 538 | If a key is defined as a prefix in more than one active map, then its |
| 539 | various definitions are in effect merged: the commands defined in the |
| 540 | minor mode keymaps come first, followed by those in the local map's |
| 541 | prefix definition, and then by those from the global map. |
| 542 | |
| 543 | In the following example, we make @kbd{C-p} a prefix key in the local |
| 544 | keymap, in such a way that @kbd{C-p} is identical to @kbd{C-x}. Then |
| 545 | the binding for @kbd{C-p C-f} is the function @code{find-file}, just |
| 546 | like @kbd{C-x C-f}. The key sequence @kbd{C-p 6} is not found in any |
| 547 | active keymap. |
| 548 | |
| 549 | @example |
| 550 | @group |
| 551 | (use-local-map (make-sparse-keymap)) |
| 552 | @result{} nil |
| 553 | @end group |
| 554 | @group |
| 555 | (local-set-key "\C-p" ctl-x-map) |
| 556 | @result{} nil |
| 557 | @end group |
| 558 | @group |
| 559 | (key-binding "\C-p\C-f") |
| 560 | @result{} find-file |
| 561 | @end group |
| 562 | |
| 563 | @group |
| 564 | (key-binding "\C-p6") |
| 565 | @result{} nil |
| 566 | @end group |
| 567 | @end example |
| 568 | |
| 569 | @defun define-prefix-command symbol &optional mapvar prompt |
| 570 | @cindex prefix command |
| 571 | @anchor{Definition of define-prefix-command} |
| 572 | This function prepares @var{symbol} for use as a prefix key's binding: |
| 573 | it creates a sparse keymap and stores it as @var{symbol}'s function |
| 574 | definition. Subsequently binding a key sequence to @var{symbol} will |
| 575 | make that key sequence into a prefix key. The return value is @code{symbol}. |
| 576 | |
| 577 | This function also sets @var{symbol} as a variable, with the keymap as |
| 578 | its value. But if @var{mapvar} is non-@code{nil}, it sets @var{mapvar} |
| 579 | as a variable instead. |
| 580 | |
| 581 | If @var{prompt} is non-@code{nil}, that becomes the overall prompt |
| 582 | string for the keymap. The prompt string should be given for menu keymaps |
| 583 | (@pxref{Defining Menus}). |
| 584 | @end defun |
| 585 | |
| 586 | @node Active Keymaps |
| 587 | @section Active Keymaps |
| 588 | @cindex active keymap |
| 589 | @cindex global keymap |
| 590 | @cindex local keymap |
| 591 | |
| 592 | Emacs normally contains many keymaps; at any given time, just a few |
| 593 | of them are @dfn{active}, meaning that they participate in the |
| 594 | interpretation of user input. All the active keymaps are used |
| 595 | together to determine what command to execute when a key is entered. |
| 596 | |
| 597 | Normally the active keymaps are the @code{keymap} property keymap, |
| 598 | the keymaps of any enabled minor modes, the current buffer's local |
| 599 | keymap, and the global keymap, in that order. Emacs searches for each |
| 600 | input key sequence in all these keymaps. @xref{Searching Keymaps}, |
| 601 | for more details of this procedure. |
| 602 | |
| 603 | When the key sequence starts with a mouse event (optionally preceded |
| 604 | by a symbolic prefix), the active keymaps are determined based on the |
| 605 | position in that event. If the event happened on a string embedded |
| 606 | with a @code{display}, @code{before-string}, or @code{after-string} |
| 607 | property (@pxref{Special Properties}), the non-@code{nil} map |
| 608 | properties of the string override those of the buffer. |
| 609 | |
| 610 | The @dfn{global keymap} holds the bindings of keys that are defined |
| 611 | regardless of the current buffer, such as @kbd{C-f}. The variable |
| 612 | @code{global-map} holds this keymap, which is always active. |
| 613 | |
| 614 | Each buffer may have another keymap, its @dfn{local keymap}, which |
| 615 | may contain new or overriding definitions for keys. The current |
| 616 | buffer's local keymap is always active except when |
| 617 | @code{overriding-local-map} overrides it. The @code{local-map} text |
| 618 | or overlay property can specify an alternative local keymap for certain |
| 619 | parts of the buffer; see @ref{Special Properties}. |
| 620 | |
| 621 | Each minor mode can have a keymap; if it does, the keymap is active |
| 622 | when the minor mode is enabled. Modes for emulation can specify |
| 623 | additional active keymaps through the variable |
| 624 | @code{emulation-mode-map-alists}. |
| 625 | |
| 626 | The highest precedence normal keymap comes from the @code{keymap} |
| 627 | text or overlay property. If that is non-@code{nil}, it is the first |
| 628 | keymap to be processed, in normal circumstances. |
| 629 | |
| 630 | However, there are also special ways for programs to substitute |
| 631 | other keymaps for some of those. The variable |
| 632 | @code{overriding-local-map}, if non-@code{nil}, specifies a keymap |
| 633 | that replaces all the usual active keymaps except the global keymap. |
| 634 | Another way to do this is with @code{overriding-terminal-local-map}; |
| 635 | it operates on a per-terminal basis. These variables are documented |
| 636 | below. |
| 637 | |
| 638 | @cindex major mode keymap |
| 639 | Since every buffer that uses the same major mode normally uses the |
| 640 | same local keymap, you can think of the keymap as local to the mode. A |
| 641 | change to the local keymap of a buffer (using @code{local-set-key}, for |
| 642 | example) is seen also in the other buffers that share that keymap. |
| 643 | |
| 644 | The local keymaps that are used for Lisp mode and some other major |
| 645 | modes exist even if they have not yet been used. These local keymaps are |
| 646 | the values of variables such as @code{lisp-mode-map}. For most major |
| 647 | modes, which are less frequently used, the local keymap is constructed |
| 648 | only when the mode is used for the first time in a session. |
| 649 | |
| 650 | The minibuffer has local keymaps, too; they contain various completion |
| 651 | and exit commands. @xref{Intro to Minibuffers}. |
| 652 | |
| 653 | Emacs has other keymaps that are used in a different way---translating |
| 654 | events within @code{read-key-sequence}. @xref{Translation Keymaps}. |
| 655 | |
| 656 | @xref{Standard Keymaps}, for a list of standard keymaps. |
| 657 | |
| 658 | @defun current-active-maps &optional olp |
| 659 | This returns the list of active keymaps that would be used by the |
| 660 | command loop in the current circumstances to look up a key sequence. |
| 661 | Normally it ignores @code{overriding-local-map} and |
| 662 | @code{overriding-terminal-local-map}, but if @var{olp} is |
| 663 | non-@code{nil} then it pays attention to them. |
| 664 | @end defun |
| 665 | |
| 666 | @defun key-binding key &optional accept-defaults no-remap position |
| 667 | This function returns the binding for @var{key} according to the |
| 668 | current active keymaps. The result is @code{nil} if @var{key} is |
| 669 | undefined in the keymaps. |
| 670 | |
| 671 | The argument @var{accept-defaults} controls checking for default |
| 672 | bindings, as in @code{lookup-key} (@pxref{Functions for Key Lookup}). |
| 673 | |
| 674 | When commands are remapped (@pxref{Remapping Commands}), |
| 675 | @code{key-binding} normally processes command remappings so as to |
| 676 | returns the remapped command that will actually be executed. However, |
| 677 | if @var{no-remap} is non-@code{nil}, @code{key-binding} ignores |
| 678 | remappings and returns the binding directly specified for @var{key}. |
| 679 | |
| 680 | If @var{key} starts with a mouse event (perhaps following a prefix |
| 681 | event), the maps to be consulted are determined based on the event's |
| 682 | position. Otherwise, they are determined based on the value of point. |
| 683 | However, you can override either of them by specifying @var{position}. |
| 684 | If @var{position} is non-@code{nil}, it should be either a buffer |
| 685 | position or an event position like the value of @code{event-start}. |
| 686 | Then the maps consulted are determined based on @var{position}. |
| 687 | |
| 688 | An error is signaled if @var{key} is not a string or a vector. |
| 689 | |
| 690 | @example |
| 691 | @group |
| 692 | (key-binding "\C-x\C-f") |
| 693 | @result{} find-file |
| 694 | @end group |
| 695 | @end example |
| 696 | @end defun |
| 697 | |
| 698 | @node Searching Keymaps |
| 699 | @section Searching the Active Keymaps |
| 700 | @cindex searching active keymaps for keys |
| 701 | |
| 702 | After translation of event subsequences (@pxref{Translation |
| 703 | Keymaps}) Emacs looks for them in the active keymaps. Here is a |
| 704 | pseudo-Lisp description of the order and conditions for searching |
| 705 | them: |
| 706 | |
| 707 | @lisp |
| 708 | (or (if overriding-terminal-local-map |
| 709 | (@var{find-in} overriding-terminal-local-map) |
| 710 | (if overriding-local-map |
| 711 | (@var{find-in} overriding-local-map) |
| 712 | (or (@var{find-in} (get-char-property (point) 'keymap)) |
| 713 | (@var{find-in-any} emulation-mode-map-alists) |
| 714 | (@var{find-in-any} minor-mode-overriding-map-alist) |
| 715 | (@var{find-in-any} minor-mode-map-alist) |
| 716 | (if (get-text-property (point) 'local-map) |
| 717 | (@var{find-in} (get-char-property (point) 'local-map)) |
| 718 | (@var{find-in} (current-local-map)))))) |
| 719 | (@var{find-in} (current-global-map))) |
| 720 | @end lisp |
| 721 | |
| 722 | @noindent |
| 723 | The @var{find-in} and @var{find-in-any} are pseudo functions that |
| 724 | search in one keymap and in an alist of keymaps, respectively. |
| 725 | (Searching a single keymap for a binding is called @dfn{key lookup}; |
| 726 | see @ref{Key Lookup}.) If the key sequence starts with a mouse event, |
| 727 | or a symbolic prefix event followed by a mouse event, that event's |
| 728 | position is used instead of point and the current buffer. Mouse |
| 729 | events on an embedded string use non-@code{nil} text properties from |
| 730 | that string instead of the buffer. |
| 731 | |
| 732 | @enumerate |
| 733 | @item |
| 734 | The function finally found may be remapped |
| 735 | (@pxref{Remapping Commands}). |
| 736 | |
| 737 | @item |
| 738 | Characters that are bound to @code{self-insert-command} are translated |
| 739 | according to @code{translation-table-for-input} before insertion. |
| 740 | |
| 741 | @item |
| 742 | @code{current-active-maps} returns a list of the |
| 743 | currently active keymaps at point. |
| 744 | |
| 745 | @item |
| 746 | When a match is found (@pxref{Key Lookup}), if the binding in the |
| 747 | keymap is a function, the search is over. However if the keymap entry |
| 748 | is a symbol with a value or a string, Emacs replaces the input key |
| 749 | sequences with the variable's value or the string, and restarts the |
| 750 | search of the active keymaps. |
| 751 | @end enumerate |
| 752 | |
| 753 | @node Controlling Active Maps |
| 754 | @section Controlling the Active Keymaps |
| 755 | |
| 756 | @defvar global-map |
| 757 | This variable contains the default global keymap that maps Emacs |
| 758 | keyboard input to commands. The global keymap is normally this |
| 759 | keymap. The default global keymap is a full keymap that binds |
| 760 | @code{self-insert-command} to all of the printing characters. |
| 761 | |
| 762 | It is normal practice to change the bindings in the global keymap, but you |
| 763 | should not assign this variable any value other than the keymap it starts |
| 764 | out with. |
| 765 | @end defvar |
| 766 | |
| 767 | @defun current-global-map |
| 768 | This function returns the current global keymap. This is the |
| 769 | same as the value of @code{global-map} unless you change one or the |
| 770 | other. |
| 771 | |
| 772 | @example |
| 773 | @group |
| 774 | (current-global-map) |
| 775 | @result{} (keymap [set-mark-command beginning-of-line @dots{} |
| 776 | delete-backward-char]) |
| 777 | @end group |
| 778 | @end example |
| 779 | @end defun |
| 780 | |
| 781 | @defun current-local-map |
| 782 | This function returns the current buffer's local keymap, or @code{nil} |
| 783 | if it has none. In the following example, the keymap for the |
| 784 | @samp{*scratch*} buffer (using Lisp Interaction mode) is a sparse keymap |
| 785 | in which the entry for @key{ESC}, @acronym{ASCII} code 27, is another sparse |
| 786 | keymap. |
| 787 | |
| 788 | @example |
| 789 | @group |
| 790 | (current-local-map) |
| 791 | @result{} (keymap |
| 792 | (10 . eval-print-last-sexp) |
| 793 | (9 . lisp-indent-line) |
| 794 | (127 . backward-delete-char-untabify) |
| 795 | @end group |
| 796 | @group |
| 797 | (27 keymap |
| 798 | (24 . eval-defun) |
| 799 | (17 . indent-sexp))) |
| 800 | @end group |
| 801 | @end example |
| 802 | @end defun |
| 803 | |
| 804 | @defun current-minor-mode-maps |
| 805 | This function returns a list of the keymaps of currently enabled minor modes. |
| 806 | @end defun |
| 807 | |
| 808 | @defun use-global-map keymap |
| 809 | This function makes @var{keymap} the new current global keymap. It |
| 810 | returns @code{nil}. |
| 811 | |
| 812 | It is very unusual to change the global keymap. |
| 813 | @end defun |
| 814 | |
| 815 | @defun use-local-map keymap |
| 816 | This function makes @var{keymap} the new local keymap of the current |
| 817 | buffer. If @var{keymap} is @code{nil}, then the buffer has no local |
| 818 | keymap. @code{use-local-map} returns @code{nil}. Most major mode |
| 819 | commands use this function. |
| 820 | @end defun |
| 821 | |
| 822 | @c Emacs 19 feature |
| 823 | @defvar minor-mode-map-alist |
| 824 | @anchor{Definition of minor-mode-map-alist} |
| 825 | This variable is an alist describing keymaps that may or may not be |
| 826 | active according to the values of certain variables. Its elements look |
| 827 | like this: |
| 828 | |
| 829 | @example |
| 830 | (@var{variable} . @var{keymap}) |
| 831 | @end example |
| 832 | |
| 833 | The keymap @var{keymap} is active whenever @var{variable} has a |
| 834 | non-@code{nil} value. Typically @var{variable} is the variable that |
| 835 | enables or disables a minor mode. @xref{Keymaps and Minor Modes}. |
| 836 | |
| 837 | Note that elements of @code{minor-mode-map-alist} do not have the same |
| 838 | structure as elements of @code{minor-mode-alist}. The map must be the |
| 839 | @sc{cdr} of the element; a list with the map as the second element will |
| 840 | not do. The @sc{cdr} can be either a keymap (a list) or a symbol whose |
| 841 | function definition is a keymap. |
| 842 | |
| 843 | When more than one minor mode keymap is active, the earlier one in |
| 844 | @code{minor-mode-map-alist} takes priority. But you should design |
| 845 | minor modes so that they don't interfere with each other. If you do |
| 846 | this properly, the order will not matter. |
| 847 | |
| 848 | See @ref{Keymaps and Minor Modes}, for more information about minor |
| 849 | modes. See also @code{minor-mode-key-binding} (@pxref{Functions for Key |
| 850 | Lookup}). |
| 851 | @end defvar |
| 852 | |
| 853 | @defvar minor-mode-overriding-map-alist |
| 854 | This variable allows major modes to override the key bindings for |
| 855 | particular minor modes. The elements of this alist look like the |
| 856 | elements of @code{minor-mode-map-alist}: @code{(@var{variable} |
| 857 | . @var{keymap})}. |
| 858 | |
| 859 | If a variable appears as an element of |
| 860 | @code{minor-mode-overriding-map-alist}, the map specified by that |
| 861 | element totally replaces any map specified for the same variable in |
| 862 | @code{minor-mode-map-alist}. |
| 863 | |
| 864 | @code{minor-mode-overriding-map-alist} is automatically buffer-local in |
| 865 | all buffers. |
| 866 | @end defvar |
| 867 | |
| 868 | @defvar overriding-local-map |
| 869 | If non-@code{nil}, this variable holds a keymap to use instead of the |
| 870 | buffer's local keymap, any text property or overlay keymaps, and any |
| 871 | minor mode keymaps. This keymap, if specified, overrides all other |
| 872 | maps that would have been active, except for the current global map. |
| 873 | @end defvar |
| 874 | |
| 875 | @defvar overriding-terminal-local-map |
| 876 | If non-@code{nil}, this variable holds a keymap to use instead of |
| 877 | @code{overriding-local-map}, the buffer's local keymap, text property |
| 878 | or overlay keymaps, and all the minor mode keymaps. |
| 879 | |
| 880 | This variable is always local to the current terminal and cannot be |
| 881 | buffer-local. @xref{Multiple Displays}. It is used to implement |
| 882 | incremental search mode. |
| 883 | @end defvar |
| 884 | |
| 885 | @defvar overriding-local-map-menu-flag |
| 886 | If this variable is non-@code{nil}, the value of |
| 887 | @code{overriding-local-map} or @code{overriding-terminal-local-map} can |
| 888 | affect the display of the menu bar. The default value is @code{nil}, so |
| 889 | those map variables have no effect on the menu bar. |
| 890 | |
| 891 | Note that these two map variables do affect the execution of key |
| 892 | sequences entered using the menu bar, even if they do not affect the |
| 893 | menu bar display. So if a menu bar key sequence comes in, you should |
| 894 | clear the variables before looking up and executing that key sequence. |
| 895 | Modes that use the variables would typically do this anyway; normally |
| 896 | they respond to events that they do not handle by ``unreading'' them and |
| 897 | exiting. |
| 898 | @end defvar |
| 899 | |
| 900 | @defvar special-event-map |
| 901 | This variable holds a keymap for special events. If an event type has a |
| 902 | binding in this keymap, then it is special, and the binding for the |
| 903 | event is run directly by @code{read-event}. @xref{Special Events}. |
| 904 | @end defvar |
| 905 | |
| 906 | @defvar emulation-mode-map-alists |
| 907 | This variable holds a list of keymap alists to use for emulations |
| 908 | modes. It is intended for modes or packages using multiple minor-mode |
| 909 | keymaps. Each element is a keymap alist which has the same format and |
| 910 | meaning as @code{minor-mode-map-alist}, or a symbol with a variable |
| 911 | binding which is such an alist. The ``active'' keymaps in each alist |
| 912 | are used before @code{minor-mode-map-alist} and |
| 913 | @code{minor-mode-overriding-map-alist}. |
| 914 | @end defvar |
| 915 | |
| 916 | @node Key Lookup |
| 917 | @section Key Lookup |
| 918 | @cindex key lookup |
| 919 | @cindex keymap entry |
| 920 | |
| 921 | @dfn{Key lookup} is the process of finding the binding of a key |
| 922 | sequence from a given keymap. The execution or use of the binding is |
| 923 | not part of key lookup. |
| 924 | |
| 925 | Key lookup uses just the event type of each event in the key sequence; |
| 926 | the rest of the event is ignored. In fact, a key sequence used for key |
| 927 | lookup may designate a mouse event with just its types (a symbol) |
| 928 | instead of the entire event (a list). @xref{Input Events}. Such |
| 929 | a ``key sequence'' is insufficient for @code{command-execute} to run, |
| 930 | but it is sufficient for looking up or rebinding a key. |
| 931 | |
| 932 | When the key sequence consists of multiple events, key lookup |
| 933 | processes the events sequentially: the binding of the first event is |
| 934 | found, and must be a keymap; then the second event's binding is found in |
| 935 | that keymap, and so on until all the events in the key sequence are used |
| 936 | up. (The binding thus found for the last event may or may not be a |
| 937 | keymap.) Thus, the process of key lookup is defined in terms of a |
| 938 | simpler process for looking up a single event in a keymap. How that is |
| 939 | done depends on the type of object associated with the event in that |
| 940 | keymap. |
| 941 | |
| 942 | Let's use the term @dfn{keymap entry} to describe the value found by |
| 943 | looking up an event type in a keymap. (This doesn't include the item |
| 944 | string and other extra elements in a keymap element for a menu item, because |
| 945 | @code{lookup-key} and other key lookup functions don't include them in |
| 946 | the returned value.) While any Lisp object may be stored in a keymap |
| 947 | as a keymap entry, not all make sense for key lookup. Here is a table |
| 948 | of the meaningful types of keymap entries: |
| 949 | |
| 950 | @table @asis |
| 951 | @item @code{nil} |
| 952 | @cindex @code{nil} in keymap |
| 953 | @code{nil} means that the events used so far in the lookup form an |
| 954 | undefined key. When a keymap fails to mention an event type at all, and |
| 955 | has no default binding, that is equivalent to a binding of @code{nil} |
| 956 | for that event type. |
| 957 | |
| 958 | @item @var{command} |
| 959 | @cindex command in keymap |
| 960 | The events used so far in the lookup form a complete key, |
| 961 | and @var{command} is its binding. @xref{What Is a Function}. |
| 962 | |
| 963 | @item @var{array} |
| 964 | @cindex string in keymap |
| 965 | The array (either a string or a vector) is a keyboard macro. The events |
| 966 | used so far in the lookup form a complete key, and the array is its |
| 967 | binding. See @ref{Keyboard Macros}, for more information. |
| 968 | |
| 969 | @item @var{keymap} |
| 970 | @cindex keymap in keymap |
| 971 | The events used so far in the lookup form a prefix key. The next |
| 972 | event of the key sequence is looked up in @var{keymap}. |
| 973 | |
| 974 | @item @var{list} |
| 975 | @cindex list in keymap |
| 976 | The meaning of a list depends on what it contains: |
| 977 | |
| 978 | @itemize @bullet |
| 979 | @item |
| 980 | If the @sc{car} of @var{list} is the symbol @code{keymap}, then the list |
| 981 | is a keymap, and is treated as a keymap (see above). |
| 982 | |
| 983 | @item |
| 984 | @cindex @code{lambda} in keymap |
| 985 | If the @sc{car} of @var{list} is @code{lambda}, then the list is a |
| 986 | lambda expression. This is presumed to be a function, and is treated |
| 987 | as such (see above). In order to execute properly as a key binding, |
| 988 | this function must be a command---it must have an @code{interactive} |
| 989 | specification. @xref{Defining Commands}. |
| 990 | |
| 991 | @item |
| 992 | If the @sc{car} of @var{list} is a keymap and the @sc{cdr} is an event |
| 993 | type, then this is an @dfn{indirect entry}: |
| 994 | |
| 995 | @example |
| 996 | (@var{othermap} . @var{othertype}) |
| 997 | @end example |
| 998 | |
| 999 | When key lookup encounters an indirect entry, it looks up instead the |
| 1000 | binding of @var{othertype} in @var{othermap} and uses that. |
| 1001 | |
| 1002 | This feature permits you to define one key as an alias for another key. |
| 1003 | For example, an entry whose @sc{car} is the keymap called @code{esc-map} |
| 1004 | and whose @sc{cdr} is 32 (the code for @key{SPC}) means, ``Use the global |
| 1005 | binding of @kbd{Meta-@key{SPC}}, whatever that may be.'' |
| 1006 | @end itemize |
| 1007 | |
| 1008 | @item @var{symbol} |
| 1009 | @cindex symbol in keymap |
| 1010 | The function definition of @var{symbol} is used in place of |
| 1011 | @var{symbol}. If that too is a symbol, then this process is repeated, |
| 1012 | any number of times. Ultimately this should lead to an object that is |
| 1013 | a keymap, a command, or a keyboard macro. A list is allowed if it is a |
| 1014 | keymap or a command, but indirect entries are not understood when found |
| 1015 | via symbols. |
| 1016 | |
| 1017 | Note that keymaps and keyboard macros (strings and vectors) are not |
| 1018 | valid functions, so a symbol with a keymap, string, or vector as its |
| 1019 | function definition is invalid as a function. It is, however, valid as |
| 1020 | a key binding. If the definition is a keyboard macro, then the symbol |
| 1021 | is also valid as an argument to @code{command-execute} |
| 1022 | (@pxref{Interactive Call}). |
| 1023 | |
| 1024 | @cindex @code{undefined} in keymap |
| 1025 | The symbol @code{undefined} is worth special mention: it means to treat |
| 1026 | the key as undefined. Strictly speaking, the key is defined, and its |
| 1027 | binding is the command @code{undefined}; but that command does the same |
| 1028 | thing that is done automatically for an undefined key: it rings the bell |
| 1029 | (by calling @code{ding}) but does not signal an error. |
| 1030 | |
| 1031 | @cindex preventing prefix key |
| 1032 | @code{undefined} is used in local keymaps to override a global key |
| 1033 | binding and make the key ``undefined'' locally. A local binding of |
| 1034 | @code{nil} would fail to do this because it would not override the |
| 1035 | global binding. |
| 1036 | |
| 1037 | @item @var{anything else} |
| 1038 | If any other type of object is found, the events used so far in the |
| 1039 | lookup form a complete key, and the object is its binding, but the |
| 1040 | binding is not executable as a command. |
| 1041 | @end table |
| 1042 | |
| 1043 | In short, a keymap entry may be a keymap, a command, a keyboard macro, |
| 1044 | a symbol that leads to one of them, or an indirection or @code{nil}. |
| 1045 | Here is an example of a sparse keymap with two characters bound to |
| 1046 | commands and one bound to another keymap. This map is the normal value |
| 1047 | of @code{emacs-lisp-mode-map}. Note that 9 is the code for @key{TAB}, |
| 1048 | 127 for @key{DEL}, 27 for @key{ESC}, 17 for @kbd{C-q} and 24 for |
| 1049 | @kbd{C-x}. |
| 1050 | |
| 1051 | @example |
| 1052 | @group |
| 1053 | (keymap (9 . lisp-indent-line) |
| 1054 | (127 . backward-delete-char-untabify) |
| 1055 | (27 keymap (17 . indent-sexp) (24 . eval-defun))) |
| 1056 | @end group |
| 1057 | @end example |
| 1058 | |
| 1059 | @node Functions for Key Lookup |
| 1060 | @section Functions for Key Lookup |
| 1061 | |
| 1062 | Here are the functions and variables pertaining to key lookup. |
| 1063 | |
| 1064 | @defun lookup-key keymap key &optional accept-defaults |
| 1065 | This function returns the definition of @var{key} in @var{keymap}. All |
| 1066 | the other functions described in this chapter that look up keys use |
| 1067 | @code{lookup-key}. Here are examples: |
| 1068 | |
| 1069 | @example |
| 1070 | @group |
| 1071 | (lookup-key (current-global-map) "\C-x\C-f") |
| 1072 | @result{} find-file |
| 1073 | @end group |
| 1074 | @group |
| 1075 | (lookup-key (current-global-map) (kbd "C-x C-f")) |
| 1076 | @result{} find-file |
| 1077 | @end group |
| 1078 | @group |
| 1079 | (lookup-key (current-global-map) "\C-x\C-f12345") |
| 1080 | @result{} 2 |
| 1081 | @end group |
| 1082 | @end example |
| 1083 | |
| 1084 | If the string or vector @var{key} is not a valid key sequence according |
| 1085 | to the prefix keys specified in @var{keymap}, it must be ``too long'' |
| 1086 | and have extra events at the end that do not fit into a single key |
| 1087 | sequence. Then the value is a number, the number of events at the front |
| 1088 | of @var{key} that compose a complete key. |
| 1089 | |
| 1090 | @c Emacs 19 feature |
| 1091 | If @var{accept-defaults} is non-@code{nil}, then @code{lookup-key} |
| 1092 | considers default bindings as well as bindings for the specific events |
| 1093 | in @var{key}. Otherwise, @code{lookup-key} reports only bindings for |
| 1094 | the specific sequence @var{key}, ignoring default bindings except when |
| 1095 | you explicitly ask about them. (To do this, supply @code{t} as an |
| 1096 | element of @var{key}; see @ref{Format of Keymaps}.) |
| 1097 | |
| 1098 | If @var{key} contains a meta character (not a function key), that |
| 1099 | character is implicitly replaced by a two-character sequence: the value |
| 1100 | of @code{meta-prefix-char}, followed by the corresponding non-meta |
| 1101 | character. Thus, the first example below is handled by conversion into |
| 1102 | the second example. |
| 1103 | |
| 1104 | @example |
| 1105 | @group |
| 1106 | (lookup-key (current-global-map) "\M-f") |
| 1107 | @result{} forward-word |
| 1108 | @end group |
| 1109 | @group |
| 1110 | (lookup-key (current-global-map) "\ef") |
| 1111 | @result{} forward-word |
| 1112 | @end group |
| 1113 | @end example |
| 1114 | |
| 1115 | Unlike @code{read-key-sequence}, this function does not modify the |
| 1116 | specified events in ways that discard information (@pxref{Key Sequence |
| 1117 | Input}). In particular, it does not convert letters to lower case and |
| 1118 | it does not change drag events to clicks. |
| 1119 | @end defun |
| 1120 | |
| 1121 | @deffn Command undefined |
| 1122 | Used in keymaps to undefine keys. It calls @code{ding}, but does |
| 1123 | not cause an error. |
| 1124 | @end deffn |
| 1125 | |
| 1126 | @defun local-key-binding key &optional accept-defaults |
| 1127 | This function returns the binding for @var{key} in the current |
| 1128 | local keymap, or @code{nil} if it is undefined there. |
| 1129 | |
| 1130 | @c Emacs 19 feature |
| 1131 | The argument @var{accept-defaults} controls checking for default bindings, |
| 1132 | as in @code{lookup-key} (above). |
| 1133 | @end defun |
| 1134 | |
| 1135 | @defun global-key-binding key &optional accept-defaults |
| 1136 | This function returns the binding for command @var{key} in the |
| 1137 | current global keymap, or @code{nil} if it is undefined there. |
| 1138 | |
| 1139 | @c Emacs 19 feature |
| 1140 | The argument @var{accept-defaults} controls checking for default bindings, |
| 1141 | as in @code{lookup-key} (above). |
| 1142 | @end defun |
| 1143 | |
| 1144 | @c Emacs 19 feature |
| 1145 | @defun minor-mode-key-binding key &optional accept-defaults |
| 1146 | This function returns a list of all the active minor mode bindings of |
| 1147 | @var{key}. More precisely, it returns an alist of pairs |
| 1148 | @code{(@var{modename} . @var{binding})}, where @var{modename} is the |
| 1149 | variable that enables the minor mode, and @var{binding} is @var{key}'s |
| 1150 | binding in that mode. If @var{key} has no minor-mode bindings, the |
| 1151 | value is @code{nil}. |
| 1152 | |
| 1153 | If the first binding found is not a prefix definition (a keymap or a |
| 1154 | symbol defined as a keymap), all subsequent bindings from other minor |
| 1155 | modes are omitted, since they would be completely shadowed. Similarly, |
| 1156 | the list omits non-prefix bindings that follow prefix bindings. |
| 1157 | |
| 1158 | The argument @var{accept-defaults} controls checking for default |
| 1159 | bindings, as in @code{lookup-key} (above). |
| 1160 | @end defun |
| 1161 | |
| 1162 | @defvar meta-prefix-char |
| 1163 | @cindex @key{ESC} |
| 1164 | This variable is the meta-prefix character code. It is used for |
| 1165 | translating a meta character to a two-character sequence so it can be |
| 1166 | looked up in a keymap. For useful results, the value should be a |
| 1167 | prefix event (@pxref{Prefix Keys}). The default value is 27, which is |
| 1168 | the @acronym{ASCII} code for @key{ESC}. |
| 1169 | |
| 1170 | As long as the value of @code{meta-prefix-char} remains 27, key lookup |
| 1171 | translates @kbd{M-b} into @kbd{@key{ESC} b}, which is normally defined |
| 1172 | as the @code{backward-word} command. However, if you were to set |
| 1173 | @code{meta-prefix-char} to 24, the code for @kbd{C-x}, then Emacs will |
| 1174 | translate @kbd{M-b} into @kbd{C-x b}, whose standard binding is the |
| 1175 | @code{switch-to-buffer} command. (Don't actually do this!) Here is an |
| 1176 | illustration of what would happen: |
| 1177 | |
| 1178 | @smallexample |
| 1179 | @group |
| 1180 | meta-prefix-char ; @r{The default value.} |
| 1181 | @result{} 27 |
| 1182 | @end group |
| 1183 | @group |
| 1184 | (key-binding "\M-b") |
| 1185 | @result{} backward-word |
| 1186 | @end group |
| 1187 | @group |
| 1188 | ?\C-x ; @r{The print representation} |
| 1189 | @result{} 24 ; @r{of a character.} |
| 1190 | @end group |
| 1191 | @group |
| 1192 | (setq meta-prefix-char 24) |
| 1193 | @result{} 24 |
| 1194 | @end group |
| 1195 | @group |
| 1196 | (key-binding "\M-b") |
| 1197 | @result{} switch-to-buffer ; @r{Now, typing @kbd{M-b} is} |
| 1198 | ; @r{like typing @kbd{C-x b}.} |
| 1199 | |
| 1200 | (setq meta-prefix-char 27) ; @r{Avoid confusion!} |
| 1201 | @result{} 27 ; @r{Restore the default value!} |
| 1202 | @end group |
| 1203 | @end smallexample |
| 1204 | |
| 1205 | This translation of one event into two happens only for characters, not |
| 1206 | for other kinds of input events. Thus, @kbd{M-@key{F1}}, a function |
| 1207 | key, is not converted into @kbd{@key{ESC} @key{F1}}. |
| 1208 | @end defvar |
| 1209 | |
| 1210 | @node Changing Key Bindings |
| 1211 | @section Changing Key Bindings |
| 1212 | @cindex changing key bindings |
| 1213 | @cindex rebinding |
| 1214 | |
| 1215 | The way to rebind a key is to change its entry in a keymap. If you |
| 1216 | change a binding in the global keymap, the change is effective in all |
| 1217 | buffers (though it has no direct effect in buffers that shadow the |
| 1218 | global binding with a local one). If you change the current buffer's |
| 1219 | local map, that usually affects all buffers using the same major mode. |
| 1220 | The @code{global-set-key} and @code{local-set-key} functions are |
| 1221 | convenient interfaces for these operations (@pxref{Key Binding |
| 1222 | Commands}). You can also use @code{define-key}, a more general |
| 1223 | function; then you must specify explicitly the map to change. |
| 1224 | |
| 1225 | When choosing the key sequences for Lisp programs to rebind, please |
| 1226 | follow the Emacs conventions for use of various keys (@pxref{Key |
| 1227 | Binding Conventions}). |
| 1228 | |
| 1229 | @cindex meta character key constants |
| 1230 | @cindex control character key constants |
| 1231 | In writing the key sequence to rebind, it is good to use the special |
| 1232 | escape sequences for control and meta characters (@pxref{String Type}). |
| 1233 | The syntax @samp{\C-} means that the following character is a control |
| 1234 | character and @samp{\M-} means that the following character is a meta |
| 1235 | character. Thus, the string @code{"\M-x"} is read as containing a |
| 1236 | single @kbd{M-x}, @code{"\C-f"} is read as containing a single |
| 1237 | @kbd{C-f}, and @code{"\M-\C-x"} and @code{"\C-\M-x"} are both read as |
| 1238 | containing a single @kbd{C-M-x}. You can also use this escape syntax in |
| 1239 | vectors, as well as others that aren't allowed in strings; one example |
| 1240 | is @samp{[?\C-\H-x home]}. @xref{Character Type}. |
| 1241 | |
| 1242 | The key definition and lookup functions accept an alternate syntax for |
| 1243 | event types in a key sequence that is a vector: you can use a list |
| 1244 | containing modifier names plus one base event (a character or function |
| 1245 | key name). For example, @code{(control ?a)} is equivalent to |
| 1246 | @code{?\C-a} and @code{(hyper control left)} is equivalent to |
| 1247 | @code{C-H-left}. One advantage of such lists is that the precise |
| 1248 | numeric codes for the modifier bits don't appear in compiled files. |
| 1249 | |
| 1250 | The functions below signal an error if @var{keymap} is not a keymap, |
| 1251 | or if @var{key} is not a string or vector representing a key sequence. |
| 1252 | You can use event types (symbols) as shorthand for events that are |
| 1253 | lists. The @code{kbd} macro (@pxref{Key Sequences}) is a convenient |
| 1254 | way to specify the key sequence. |
| 1255 | |
| 1256 | @defun define-key keymap key binding |
| 1257 | This function sets the binding for @var{key} in @var{keymap}. (If |
| 1258 | @var{key} is more than one event long, the change is actually made |
| 1259 | in another keymap reached from @var{keymap}.) The argument |
| 1260 | @var{binding} can be any Lisp object, but only certain types are |
| 1261 | meaningful. (For a list of meaningful types, see @ref{Key Lookup}.) |
| 1262 | The value returned by @code{define-key} is @var{binding}. |
| 1263 | |
| 1264 | If @var{key} is @code{[t]}, this sets the default binding in |
| 1265 | @var{keymap}. When an event has no binding of its own, the Emacs |
| 1266 | command loop uses the keymap's default binding, if there is one. |
| 1267 | |
| 1268 | @cindex invalid prefix key error |
| 1269 | @cindex key sequence error |
| 1270 | Every prefix of @var{key} must be a prefix key (i.e., bound to a keymap) |
| 1271 | or undefined; otherwise an error is signaled. If some prefix of |
| 1272 | @var{key} is undefined, then @code{define-key} defines it as a prefix |
| 1273 | key so that the rest of @var{key} can be defined as specified. |
| 1274 | |
| 1275 | If there was previously no binding for @var{key} in @var{keymap}, the |
| 1276 | new binding is added at the beginning of @var{keymap}. The order of |
| 1277 | bindings in a keymap makes no difference for keyboard input, but it |
| 1278 | does matter for menu keymaps (@pxref{Menu Keymaps}). |
| 1279 | @end defun |
| 1280 | |
| 1281 | This example creates a sparse keymap and makes a number of |
| 1282 | bindings in it: |
| 1283 | |
| 1284 | @smallexample |
| 1285 | @group |
| 1286 | (setq map (make-sparse-keymap)) |
| 1287 | @result{} (keymap) |
| 1288 | @end group |
| 1289 | @group |
| 1290 | (define-key map "\C-f" 'forward-char) |
| 1291 | @result{} forward-char |
| 1292 | @end group |
| 1293 | @group |
| 1294 | map |
| 1295 | @result{} (keymap (6 . forward-char)) |
| 1296 | @end group |
| 1297 | |
| 1298 | @group |
| 1299 | ;; @r{Build sparse submap for @kbd{C-x} and bind @kbd{f} in that.} |
| 1300 | (define-key map (kbd "C-x f") 'forward-word) |
| 1301 | @result{} forward-word |
| 1302 | @end group |
| 1303 | @group |
| 1304 | map |
| 1305 | @result{} (keymap |
| 1306 | (24 keymap ; @kbd{C-x} |
| 1307 | (102 . forward-word)) ; @kbd{f} |
| 1308 | (6 . forward-char)) ; @kbd{C-f} |
| 1309 | @end group |
| 1310 | |
| 1311 | @group |
| 1312 | ;; @r{Bind @kbd{C-p} to the @code{ctl-x-map}.} |
| 1313 | (define-key map (kbd "C-p") ctl-x-map) |
| 1314 | ;; @code{ctl-x-map} |
| 1315 | @result{} [nil @dots{} find-file @dots{} backward-kill-sentence] |
| 1316 | @end group |
| 1317 | |
| 1318 | @group |
| 1319 | ;; @r{Bind @kbd{C-f} to @code{foo} in the @code{ctl-x-map}.} |
| 1320 | (define-key map (kbd "C-p C-f") 'foo) |
| 1321 | @result{} 'foo |
| 1322 | @end group |
| 1323 | @group |
| 1324 | map |
| 1325 | @result{} (keymap ; @r{Note @code{foo} in @code{ctl-x-map}.} |
| 1326 | (16 keymap [nil @dots{} foo @dots{} backward-kill-sentence]) |
| 1327 | (24 keymap |
| 1328 | (102 . forward-word)) |
| 1329 | (6 . forward-char)) |
| 1330 | @end group |
| 1331 | @end smallexample |
| 1332 | |
| 1333 | @noindent |
| 1334 | Note that storing a new binding for @kbd{C-p C-f} actually works by |
| 1335 | changing an entry in @code{ctl-x-map}, and this has the effect of |
| 1336 | changing the bindings of both @kbd{C-p C-f} and @kbd{C-x C-f} in the |
| 1337 | default global map. |
| 1338 | |
| 1339 | The function @code{substitute-key-definition} scans a keymap for |
| 1340 | keys that have a certain binding and rebinds them with a different |
| 1341 | binding. Another feature which is cleaner and can often produce the |
| 1342 | same results to remap one command into another (@pxref{Remapping |
| 1343 | Commands}). |
| 1344 | |
| 1345 | @defun substitute-key-definition olddef newdef keymap &optional oldmap |
| 1346 | @cindex replace bindings |
| 1347 | This function replaces @var{olddef} with @var{newdef} for any keys in |
| 1348 | @var{keymap} that were bound to @var{olddef}. In other words, |
| 1349 | @var{olddef} is replaced with @var{newdef} wherever it appears. The |
| 1350 | function returns @code{nil}. |
| 1351 | |
| 1352 | For example, this redefines @kbd{C-x C-f}, if you do it in an Emacs with |
| 1353 | standard bindings: |
| 1354 | |
| 1355 | @smallexample |
| 1356 | @group |
| 1357 | (substitute-key-definition |
| 1358 | 'find-file 'find-file-read-only (current-global-map)) |
| 1359 | @end group |
| 1360 | @end smallexample |
| 1361 | |
| 1362 | @c Emacs 19 feature |
| 1363 | If @var{oldmap} is non-@code{nil}, that changes the behavior of |
| 1364 | @code{substitute-key-definition}: the bindings in @var{oldmap} determine |
| 1365 | which keys to rebind. The rebindings still happen in @var{keymap}, not |
| 1366 | in @var{oldmap}. Thus, you can change one map under the control of the |
| 1367 | bindings in another. For example, |
| 1368 | |
| 1369 | @smallexample |
| 1370 | (substitute-key-definition |
| 1371 | 'delete-backward-char 'my-funny-delete |
| 1372 | my-map global-map) |
| 1373 | @end smallexample |
| 1374 | |
| 1375 | @noindent |
| 1376 | puts the special deletion command in @code{my-map} for whichever keys |
| 1377 | are globally bound to the standard deletion command. |
| 1378 | |
| 1379 | Here is an example showing a keymap before and after substitution: |
| 1380 | |
| 1381 | @smallexample |
| 1382 | @group |
| 1383 | (setq map '(keymap |
| 1384 | (?1 . olddef-1) |
| 1385 | (?2 . olddef-2) |
| 1386 | (?3 . olddef-1))) |
| 1387 | @result{} (keymap (49 . olddef-1) (50 . olddef-2) (51 . olddef-1)) |
| 1388 | @end group |
| 1389 | |
| 1390 | @group |
| 1391 | (substitute-key-definition 'olddef-1 'newdef map) |
| 1392 | @result{} nil |
| 1393 | @end group |
| 1394 | @group |
| 1395 | map |
| 1396 | @result{} (keymap (49 . newdef) (50 . olddef-2) (51 . newdef)) |
| 1397 | @end group |
| 1398 | @end smallexample |
| 1399 | @end defun |
| 1400 | |
| 1401 | @defun suppress-keymap keymap &optional nodigits |
| 1402 | @cindex @code{self-insert-command} override |
| 1403 | This function changes the contents of the full keymap @var{keymap} by |
| 1404 | remapping @code{self-insert-command} to the command @code{undefined} |
| 1405 | (@pxref{Remapping Commands}). This has the effect of undefining all |
| 1406 | printing characters, thus making ordinary insertion of text impossible. |
| 1407 | @code{suppress-keymap} returns @code{nil}. |
| 1408 | |
| 1409 | If @var{nodigits} is @code{nil}, then @code{suppress-keymap} defines |
| 1410 | digits to run @code{digit-argument}, and @kbd{-} to run |
| 1411 | @code{negative-argument}. Otherwise it makes them undefined like the |
| 1412 | rest of the printing characters. |
| 1413 | |
| 1414 | @cindex yank suppression |
| 1415 | @cindex @code{quoted-insert} suppression |
| 1416 | The @code{suppress-keymap} function does not make it impossible to |
| 1417 | modify a buffer, as it does not suppress commands such as @code{yank} |
| 1418 | and @code{quoted-insert}. To prevent any modification of a buffer, make |
| 1419 | it read-only (@pxref{Read Only Buffers}). |
| 1420 | |
| 1421 | Since this function modifies @var{keymap}, you would normally use it |
| 1422 | on a newly created keymap. Operating on an existing keymap |
| 1423 | that is used for some other purpose is likely to cause trouble; for |
| 1424 | example, suppressing @code{global-map} would make it impossible to use |
| 1425 | most of Emacs. |
| 1426 | |
| 1427 | Most often, @code{suppress-keymap} is used to initialize local |
| 1428 | keymaps of modes such as Rmail and Dired where insertion of text is not |
| 1429 | desirable and the buffer is read-only. Here is an example taken from |
| 1430 | the file @file{emacs/lisp/dired.el}, showing how the local keymap for |
| 1431 | Dired mode is set up: |
| 1432 | |
| 1433 | @smallexample |
| 1434 | @group |
| 1435 | (setq dired-mode-map (make-keymap)) |
| 1436 | (suppress-keymap dired-mode-map) |
| 1437 | (define-key dired-mode-map "r" 'dired-rename-file) |
| 1438 | (define-key dired-mode-map "\C-d" 'dired-flag-file-deleted) |
| 1439 | (define-key dired-mode-map "d" 'dired-flag-file-deleted) |
| 1440 | (define-key dired-mode-map "v" 'dired-view-file) |
| 1441 | (define-key dired-mode-map "e" 'dired-find-file) |
| 1442 | (define-key dired-mode-map "f" 'dired-find-file) |
| 1443 | @dots{} |
| 1444 | @end group |
| 1445 | @end smallexample |
| 1446 | @end defun |
| 1447 | |
| 1448 | @node Remapping Commands |
| 1449 | @section Remapping Commands |
| 1450 | @cindex remapping commands |
| 1451 | |
| 1452 | A special kind of key binding, using a special ``key sequence'' |
| 1453 | which includes a command name, has the effect of @dfn{remapping} that |
| 1454 | command into another. Here's how it works. You make a key binding |
| 1455 | for a key sequence that starts with the dummy event @code{remap}, |
| 1456 | followed by the command name you want to remap. Specify the remapped |
| 1457 | definition as the definition in this binding. The remapped definition |
| 1458 | is usually a command name, but it can be any valid definition for |
| 1459 | a key binding. |
| 1460 | |
| 1461 | Here's an example. Suppose that My mode uses special commands |
| 1462 | @code{my-kill-line} and @code{my-kill-word}, which should be invoked |
| 1463 | instead of @code{kill-line} and @code{kill-word}. It can establish |
| 1464 | this by making these two command-remapping bindings in its keymap: |
| 1465 | |
| 1466 | @smallexample |
| 1467 | (define-key my-mode-map [remap kill-line] 'my-kill-line) |
| 1468 | (define-key my-mode-map [remap kill-word] 'my-kill-word) |
| 1469 | @end smallexample |
| 1470 | |
| 1471 | Whenever @code{my-mode-map} is an active keymap, if the user types |
| 1472 | @kbd{C-k}, Emacs will find the standard global binding of |
| 1473 | @code{kill-line} (assuming nobody has changed it). But |
| 1474 | @code{my-mode-map} remaps @code{kill-line} to @code{my-kill-line}, |
| 1475 | so instead of running @code{kill-line}, Emacs runs |
| 1476 | @code{my-kill-line}. |
| 1477 | |
| 1478 | Remapping only works through a single level. In other words, |
| 1479 | |
| 1480 | @smallexample |
| 1481 | (define-key my-mode-map [remap kill-line] 'my-kill-line) |
| 1482 | (define-key my-mode-map [remap my-kill-line] 'my-other-kill-line) |
| 1483 | @end smallexample |
| 1484 | |
| 1485 | @noindent |
| 1486 | does not have the effect of remapping @code{kill-line} into |
| 1487 | @code{my-other-kill-line}. If an ordinary key binding specifies |
| 1488 | @code{kill-line}, this keymap will remap it to @code{my-kill-line}; |
| 1489 | if an ordinary binding specifies @code{my-kill-line}, this keymap will |
| 1490 | remap it to @code{my-other-kill-line}. |
| 1491 | |
| 1492 | @defun command-remapping command &optional position keymaps |
| 1493 | This function returns the remapping for @var{command} (a symbol), |
| 1494 | given the current active keymaps. If @var{command} is not remapped |
| 1495 | (which is the usual situation), or not a symbol, the function returns |
| 1496 | @code{nil}. @code{position} can optionally specify a buffer position |
| 1497 | or an event position to determine the keymaps to use, as in |
| 1498 | @code{key-binding}. |
| 1499 | |
| 1500 | If the optional argument @code{keymaps} is non-@code{nil}, it |
| 1501 | specifies a list of keymaps to search in. This argument is ignored if |
| 1502 | @code{position} is non-@code{nil}. |
| 1503 | @end defun |
| 1504 | |
| 1505 | @node Translation Keymaps |
| 1506 | @section Keymaps for Translating Sequences of Events |
| 1507 | @cindex keymaps for translating events |
| 1508 | |
| 1509 | This section describes keymaps that are used during reading a key |
| 1510 | sequence, to translate certain event sequences into others. |
| 1511 | @code{read-key-sequence} checks every subsequence of the key sequence |
| 1512 | being read, as it is read, against @code{function-key-map} and then |
| 1513 | against @code{key-translation-map}. |
| 1514 | |
| 1515 | @defvar function-key-map |
| 1516 | This variable holds a keymap that describes the character sequences sent |
| 1517 | by function keys on an ordinary character terminal. This keymap has the |
| 1518 | same structure as other keymaps, but is used differently: it specifies |
| 1519 | translations to make while reading key sequences, rather than bindings |
| 1520 | for key sequences. |
| 1521 | |
| 1522 | If @code{function-key-map} ``binds'' a key sequence @var{k} to a vector |
| 1523 | @var{v}, then when @var{k} appears as a subsequence @emph{anywhere} in a |
| 1524 | key sequence, it is replaced with the events in @var{v}. |
| 1525 | |
| 1526 | For example, VT100 terminals send @kbd{@key{ESC} O P} when the |
| 1527 | keypad @key{PF1} key is pressed. Therefore, we want Emacs to translate |
| 1528 | that sequence of events into the single event @code{pf1}. We accomplish |
| 1529 | this by ``binding'' @kbd{@key{ESC} O P} to @code{[pf1]} in |
| 1530 | @code{function-key-map}, when using a VT100. |
| 1531 | |
| 1532 | Thus, typing @kbd{C-c @key{PF1}} sends the character sequence @kbd{C-c |
| 1533 | @key{ESC} O P}; later the function @code{read-key-sequence} translates |
| 1534 | this back into @kbd{C-c @key{PF1}}, which it returns as the vector |
| 1535 | @code{[?\C-c pf1]}. |
| 1536 | |
| 1537 | Entries in @code{function-key-map} are ignored if they conflict with |
| 1538 | bindings made in the minor mode, local, or global keymaps. The intent |
| 1539 | is that the character sequences that function keys send should not have |
| 1540 | command bindings in their own right---but if they do, the ordinary |
| 1541 | bindings take priority. |
| 1542 | |
| 1543 | The value of @code{function-key-map} is usually set up automatically |
| 1544 | according to the terminal's Terminfo or Termcap entry, but sometimes |
| 1545 | those need help from terminal-specific Lisp files. Emacs comes with |
| 1546 | terminal-specific files for many common terminals; their main purpose is |
| 1547 | to make entries in @code{function-key-map} beyond those that can be |
| 1548 | deduced from Termcap and Terminfo. @xref{Terminal-Specific}. |
| 1549 | @end defvar |
| 1550 | |
| 1551 | @defvar key-translation-map |
| 1552 | This variable is another keymap used just like @code{function-key-map} |
| 1553 | to translate input events into other events. It differs from |
| 1554 | @code{function-key-map} in two ways: |
| 1555 | |
| 1556 | @itemize @bullet |
| 1557 | @item |
| 1558 | @code{key-translation-map} goes to work after @code{function-key-map} is |
| 1559 | finished; it receives the results of translation by |
| 1560 | @code{function-key-map}. |
| 1561 | |
| 1562 | @item |
| 1563 | Non-prefix bindings in @code{key-translation-map} override actual key |
| 1564 | bindings. For example, if @kbd{C-x f} has a non-prefix binding in |
| 1565 | @code{key-translation-map}, that translation takes effect even though |
| 1566 | @kbd{C-x f} also has a key binding in the global map. |
| 1567 | @end itemize |
| 1568 | |
| 1569 | Note however that actual key bindings can have an effect on |
| 1570 | @code{key-translation-map}, even though they are overridden by it. |
| 1571 | Indeed, actual key bindings override @code{function-key-map} and thus |
| 1572 | may alter the key sequence that @code{key-translation-map} receives. |
| 1573 | Clearly, it is better to avoid this type of situation. |
| 1574 | |
| 1575 | The intent of @code{key-translation-map} is for users to map one |
| 1576 | character set to another, including ordinary characters normally bound |
| 1577 | to @code{self-insert-command}. |
| 1578 | @end defvar |
| 1579 | |
| 1580 | @cindex key translation function |
| 1581 | You can use @code{function-key-map} or @code{key-translation-map} for |
| 1582 | more than simple aliases, by using a function, instead of a key |
| 1583 | sequence, as the ``translation'' of a key. Then this function is called |
| 1584 | to compute the translation of that key. |
| 1585 | |
| 1586 | The key translation function receives one argument, which is the prompt |
| 1587 | that was specified in @code{read-key-sequence}---or @code{nil} if the |
| 1588 | key sequence is being read by the editor command loop. In most cases |
| 1589 | you can ignore the prompt value. |
| 1590 | |
| 1591 | If the function reads input itself, it can have the effect of altering |
| 1592 | the event that follows. For example, here's how to define @kbd{C-c h} |
| 1593 | to turn the character that follows into a Hyper character: |
| 1594 | |
| 1595 | @example |
| 1596 | @group |
| 1597 | (defun hyperify (prompt) |
| 1598 | (let ((e (read-event))) |
| 1599 | (vector (if (numberp e) |
| 1600 | (logior (lsh 1 24) e) |
| 1601 | (if (memq 'hyper (event-modifiers e)) |
| 1602 | e |
| 1603 | (add-event-modifier "H-" e)))))) |
| 1604 | |
| 1605 | (defun add-event-modifier (string e) |
| 1606 | (let ((symbol (if (symbolp e) e (car e)))) |
| 1607 | (setq symbol (intern (concat string |
| 1608 | (symbol-name symbol)))) |
| 1609 | @end group |
| 1610 | @group |
| 1611 | (if (symbolp e) |
| 1612 | symbol |
| 1613 | (cons symbol (cdr e))))) |
| 1614 | |
| 1615 | (define-key function-key-map "\C-ch" 'hyperify) |
| 1616 | @end group |
| 1617 | @end example |
| 1618 | |
| 1619 | If you have enabled keyboard character set decoding using |
| 1620 | @code{set-keyboard-coding-system}, decoding is done after the |
| 1621 | translations listed above. @xref{Terminal I/O Encoding}. However, in |
| 1622 | future Emacs versions, character set decoding may be done at an |
| 1623 | earlier stage. |
| 1624 | |
| 1625 | @node Key Binding Commands |
| 1626 | @section Commands for Binding Keys |
| 1627 | |
| 1628 | This section describes some convenient interactive interfaces for |
| 1629 | changing key bindings. They work by calling @code{define-key}. |
| 1630 | |
| 1631 | People often use @code{global-set-key} in their init files |
| 1632 | (@pxref{Init File}) for simple customization. For example, |
| 1633 | |
| 1634 | @smallexample |
| 1635 | (global-set-key (kbd "C-x C-\\") 'next-line) |
| 1636 | @end smallexample |
| 1637 | |
| 1638 | @noindent |
| 1639 | or |
| 1640 | |
| 1641 | @smallexample |
| 1642 | (global-set-key [?\C-x ?\C-\\] 'next-line) |
| 1643 | @end smallexample |
| 1644 | |
| 1645 | @noindent |
| 1646 | or |
| 1647 | |
| 1648 | @smallexample |
| 1649 | (global-set-key [(control ?x) (control ?\\)] 'next-line) |
| 1650 | @end smallexample |
| 1651 | |
| 1652 | @noindent |
| 1653 | redefines @kbd{C-x C-\} to move down a line. |
| 1654 | |
| 1655 | @smallexample |
| 1656 | (global-set-key [M-mouse-1] 'mouse-set-point) |
| 1657 | @end smallexample |
| 1658 | |
| 1659 | @noindent |
| 1660 | redefines the first (leftmost) mouse button, entered with the Meta key, to |
| 1661 | set point where you click. |
| 1662 | |
| 1663 | @cindex non-@acronym{ASCII} text in keybindings |
| 1664 | Be careful when using non-@acronym{ASCII} text characters in Lisp |
| 1665 | specifications of keys to bind. If these are read as multibyte text, as |
| 1666 | they usually will be in a Lisp file (@pxref{Loading Non-ASCII}), you |
| 1667 | must type the keys as multibyte too. For instance, if you use this: |
| 1668 | |
| 1669 | @smallexample |
| 1670 | (global-set-key "@"o" 'my-function) ; bind o-umlaut |
| 1671 | @end smallexample |
| 1672 | |
| 1673 | @noindent |
| 1674 | or |
| 1675 | |
| 1676 | @smallexample |
| 1677 | (global-set-key ?@"o 'my-function) ; bind o-umlaut |
| 1678 | @end smallexample |
| 1679 | |
| 1680 | @noindent |
| 1681 | and your language environment is multibyte Latin-1, these commands |
| 1682 | actually bind the multibyte character with code 2294, not the unibyte |
| 1683 | Latin-1 character with code 246 (@kbd{M-v}). In order to use this |
| 1684 | binding, you need to enter the multibyte Latin-1 character as keyboard |
| 1685 | input. One way to do this is by using an appropriate input method |
| 1686 | (@pxref{Input Methods, , Input Methods, emacs, The GNU Emacs Manual}). |
| 1687 | |
| 1688 | If you want to use a unibyte character in the key binding, you can |
| 1689 | construct the key sequence string using @code{multibyte-char-to-unibyte} |
| 1690 | or @code{string-make-unibyte} (@pxref{Converting Representations}). |
| 1691 | |
| 1692 | @deffn Command global-set-key key binding |
| 1693 | This function sets the binding of @var{key} in the current global map |
| 1694 | to @var{binding}. |
| 1695 | |
| 1696 | @smallexample |
| 1697 | @group |
| 1698 | (global-set-key @var{key} @var{binding}) |
| 1699 | @equiv{} |
| 1700 | (define-key (current-global-map) @var{key} @var{binding}) |
| 1701 | @end group |
| 1702 | @end smallexample |
| 1703 | @end deffn |
| 1704 | |
| 1705 | @deffn Command global-unset-key key |
| 1706 | @cindex unbinding keys |
| 1707 | This function removes the binding of @var{key} from the current |
| 1708 | global map. |
| 1709 | |
| 1710 | One use of this function is in preparation for defining a longer key |
| 1711 | that uses @var{key} as a prefix---which would not be allowed if |
| 1712 | @var{key} has a non-prefix binding. For example: |
| 1713 | |
| 1714 | @smallexample |
| 1715 | @group |
| 1716 | (global-unset-key "\C-l") |
| 1717 | @result{} nil |
| 1718 | @end group |
| 1719 | @group |
| 1720 | (global-set-key "\C-l\C-l" 'redraw-display) |
| 1721 | @result{} nil |
| 1722 | @end group |
| 1723 | @end smallexample |
| 1724 | |
| 1725 | This function is implemented simply using @code{define-key}: |
| 1726 | |
| 1727 | @smallexample |
| 1728 | @group |
| 1729 | (global-unset-key @var{key}) |
| 1730 | @equiv{} |
| 1731 | (define-key (current-global-map) @var{key} nil) |
| 1732 | @end group |
| 1733 | @end smallexample |
| 1734 | @end deffn |
| 1735 | |
| 1736 | @deffn Command local-set-key key binding |
| 1737 | This function sets the binding of @var{key} in the current local |
| 1738 | keymap to @var{binding}. |
| 1739 | |
| 1740 | @smallexample |
| 1741 | @group |
| 1742 | (local-set-key @var{key} @var{binding}) |
| 1743 | @equiv{} |
| 1744 | (define-key (current-local-map) @var{key} @var{binding}) |
| 1745 | @end group |
| 1746 | @end smallexample |
| 1747 | @end deffn |
| 1748 | |
| 1749 | @deffn Command local-unset-key key |
| 1750 | This function removes the binding of @var{key} from the current |
| 1751 | local map. |
| 1752 | |
| 1753 | @smallexample |
| 1754 | @group |
| 1755 | (local-unset-key @var{key}) |
| 1756 | @equiv{} |
| 1757 | (define-key (current-local-map) @var{key} nil) |
| 1758 | @end group |
| 1759 | @end smallexample |
| 1760 | @end deffn |
| 1761 | |
| 1762 | @node Scanning Keymaps |
| 1763 | @section Scanning Keymaps |
| 1764 | |
| 1765 | This section describes functions used to scan all the current keymaps |
| 1766 | for the sake of printing help information. |
| 1767 | |
| 1768 | @defun accessible-keymaps keymap &optional prefix |
| 1769 | This function returns a list of all the keymaps that can be reached (via |
| 1770 | zero or more prefix keys) from @var{keymap}. The value is an |
| 1771 | association list with elements of the form @code{(@var{key} .@: |
| 1772 | @var{map})}, where @var{key} is a prefix key whose definition in |
| 1773 | @var{keymap} is @var{map}. |
| 1774 | |
| 1775 | The elements of the alist are ordered so that the @var{key} increases |
| 1776 | in length. The first element is always @code{([] .@: @var{keymap})}, |
| 1777 | because the specified keymap is accessible from itself with a prefix of |
| 1778 | no events. |
| 1779 | |
| 1780 | If @var{prefix} is given, it should be a prefix key sequence; then |
| 1781 | @code{accessible-keymaps} includes only the submaps whose prefixes start |
| 1782 | with @var{prefix}. These elements look just as they do in the value of |
| 1783 | @code{(accessible-keymaps)}; the only difference is that some elements |
| 1784 | are omitted. |
| 1785 | |
| 1786 | In the example below, the returned alist indicates that the key |
| 1787 | @key{ESC}, which is displayed as @samp{^[}, is a prefix key whose |
| 1788 | definition is the sparse keymap @code{(keymap (83 .@: center-paragraph) |
| 1789 | (115 .@: foo))}. |
| 1790 | |
| 1791 | @smallexample |
| 1792 | @group |
| 1793 | (accessible-keymaps (current-local-map)) |
| 1794 | @result{}(([] keymap |
| 1795 | (27 keymap ; @r{Note this keymap for @key{ESC} is repeated below.} |
| 1796 | (83 . center-paragraph) |
| 1797 | (115 . center-line)) |
| 1798 | (9 . tab-to-tab-stop)) |
| 1799 | @end group |
| 1800 | |
| 1801 | @group |
| 1802 | ("^[" keymap |
| 1803 | (83 . center-paragraph) |
| 1804 | (115 . foo))) |
| 1805 | @end group |
| 1806 | @end smallexample |
| 1807 | |
| 1808 | In the following example, @kbd{C-h} is a prefix key that uses a sparse |
| 1809 | keymap starting with @code{(keymap (118 . describe-variable)@dots{})}. |
| 1810 | Another prefix, @kbd{C-x 4}, uses a keymap which is also the value of |
| 1811 | the variable @code{ctl-x-4-map}. The event @code{mode-line} is one of |
| 1812 | several dummy events used as prefixes for mouse actions in special parts |
| 1813 | of a window. |
| 1814 | |
| 1815 | @smallexample |
| 1816 | @group |
| 1817 | (accessible-keymaps (current-global-map)) |
| 1818 | @result{} (([] keymap [set-mark-command beginning-of-line @dots{} |
| 1819 | delete-backward-char]) |
| 1820 | @end group |
| 1821 | @group |
| 1822 | ("^H" keymap (118 . describe-variable) @dots{} |
| 1823 | (8 . help-for-help)) |
| 1824 | @end group |
| 1825 | @group |
| 1826 | ("^X" keymap [x-flush-mouse-queue @dots{} |
| 1827 | backward-kill-sentence]) |
| 1828 | @end group |
| 1829 | @group |
| 1830 | ("^[" keymap [mark-sexp backward-sexp @dots{} |
| 1831 | backward-kill-word]) |
| 1832 | @end group |
| 1833 | ("^X4" keymap (15 . display-buffer) @dots{}) |
| 1834 | @group |
| 1835 | ([mode-line] keymap |
| 1836 | (S-mouse-2 . mouse-split-window-horizontally) @dots{})) |
| 1837 | @end group |
| 1838 | @end smallexample |
| 1839 | |
| 1840 | @noindent |
| 1841 | These are not all the keymaps you would see in actuality. |
| 1842 | @end defun |
| 1843 | |
| 1844 | @defun map-keymap function keymap |
| 1845 | The function @code{map-keymap} calls @var{function} once |
| 1846 | for each binding in @var{keymap}. It passes two arguments, |
| 1847 | the event type and the value of the binding. If @var{keymap} |
| 1848 | has a parent, the parent's bindings are included as well. |
| 1849 | This works recursively: if the parent has itself a parent, then the |
| 1850 | grandparent's bindings are also included and so on. |
| 1851 | |
| 1852 | This function is the cleanest way to examine all the bindings |
| 1853 | in a keymap. |
| 1854 | @end defun |
| 1855 | |
| 1856 | @defun where-is-internal command &optional keymap firstonly noindirect no-remap |
| 1857 | This function is a subroutine used by the @code{where-is} command |
| 1858 | (@pxref{Help, , Help, emacs,The GNU Emacs Manual}). It returns a list |
| 1859 | of all key sequences (of any length) that are bound to @var{command} in a |
| 1860 | set of keymaps. |
| 1861 | |
| 1862 | The argument @var{command} can be any object; it is compared with all |
| 1863 | keymap entries using @code{eq}. |
| 1864 | |
| 1865 | If @var{keymap} is @code{nil}, then the maps used are the current active |
| 1866 | keymaps, disregarding @code{overriding-local-map} (that is, pretending |
| 1867 | its value is @code{nil}). If @var{keymap} is a keymap, then the |
| 1868 | maps searched are @var{keymap} and the global keymap. If @var{keymap} |
| 1869 | is a list of keymaps, only those keymaps are searched. |
| 1870 | |
| 1871 | Usually it's best to use @code{overriding-local-map} as the expression |
| 1872 | for @var{keymap}. Then @code{where-is-internal} searches precisely the |
| 1873 | keymaps that are active. To search only the global map, pass |
| 1874 | @code{(keymap)} (an empty keymap) as @var{keymap}. |
| 1875 | |
| 1876 | If @var{firstonly} is @code{non-ascii}, then the value is a single |
| 1877 | vector representing the first key sequence found, rather than a list of |
| 1878 | all possible key sequences. If @var{firstonly} is @code{t}, then the |
| 1879 | value is the first key sequence, except that key sequences consisting |
| 1880 | entirely of @acronym{ASCII} characters (or meta variants of @acronym{ASCII} |
| 1881 | characters) are preferred to all other key sequences and that the |
| 1882 | return value can never be a menu binding. |
| 1883 | |
| 1884 | If @var{noindirect} is non-@code{nil}, @code{where-is-internal} doesn't |
| 1885 | follow indirect keymap bindings. This makes it possible to search for |
| 1886 | an indirect definition itself. |
| 1887 | |
| 1888 | When command remapping is in effect (@pxref{Remapping Commands}), |
| 1889 | @code{where-is-internal} figures out when a command will be run due to |
| 1890 | remapping and reports keys accordingly. It also returns @code{nil} if |
| 1891 | @var{command} won't really be run because it has been remapped to some |
| 1892 | other command. However, if @var{no-remap} is non-@code{nil}. |
| 1893 | @code{where-is-internal} ignores remappings. |
| 1894 | |
| 1895 | @smallexample |
| 1896 | @group |
| 1897 | (where-is-internal 'describe-function) |
| 1898 | @result{} ("\^hf" "\^hd") |
| 1899 | @end group |
| 1900 | @end smallexample |
| 1901 | @end defun |
| 1902 | |
| 1903 | @deffn Command describe-bindings &optional prefix buffer-or-name |
| 1904 | This function creates a listing of all current key bindings, and |
| 1905 | displays it in a buffer named @samp{*Help*}. The text is grouped by |
| 1906 | modes---minor modes first, then the major mode, then global bindings. |
| 1907 | |
| 1908 | If @var{prefix} is non-@code{nil}, it should be a prefix key; then the |
| 1909 | listing includes only keys that start with @var{prefix}. |
| 1910 | |
| 1911 | The listing describes meta characters as @key{ESC} followed by the |
| 1912 | corresponding non-meta character. |
| 1913 | |
| 1914 | When several characters with consecutive @acronym{ASCII} codes have the |
| 1915 | same definition, they are shown together, as |
| 1916 | @samp{@var{firstchar}..@var{lastchar}}. In this instance, you need to |
| 1917 | know the @acronym{ASCII} codes to understand which characters this means. |
| 1918 | For example, in the default global map, the characters @samp{@key{SPC} |
| 1919 | ..@: ~} are described by a single line. @key{SPC} is @acronym{ASCII} 32, |
| 1920 | @kbd{~} is @acronym{ASCII} 126, and the characters between them include all |
| 1921 | the normal printing characters, (e.g., letters, digits, punctuation, |
| 1922 | etc.@:); all these characters are bound to @code{self-insert-command}. |
| 1923 | |
| 1924 | If @var{buffer-or-name} is non-@code{nil}, it should be a buffer or a |
| 1925 | buffer name. Then @code{describe-bindings} lists that buffer's bindings, |
| 1926 | instead of the current buffer's. |
| 1927 | @end deffn |
| 1928 | |
| 1929 | @node Menu Keymaps |
| 1930 | @section Menu Keymaps |
| 1931 | @cindex menu keymaps |
| 1932 | |
| 1933 | A keymap can operate as a menu as well as defining bindings for |
| 1934 | keyboard keys and mouse buttons. Menus are usually actuated with the |
| 1935 | mouse, but they can function with the keyboard also. If a menu keymap |
| 1936 | is active for the next input event, that activates the keyboard menu |
| 1937 | feature. |
| 1938 | |
| 1939 | @menu |
| 1940 | * Defining Menus:: How to make a keymap that defines a menu. |
| 1941 | * Mouse Menus:: How users actuate the menu with the mouse. |
| 1942 | * Keyboard Menus:: How users actuate the menu with the keyboard. |
| 1943 | * Menu Example:: Making a simple menu. |
| 1944 | * Menu Bar:: How to customize the menu bar. |
| 1945 | * Tool Bar:: A tool bar is a row of images. |
| 1946 | * Modifying Menus:: How to add new items to a menu. |
| 1947 | @end menu |
| 1948 | |
| 1949 | @node Defining Menus |
| 1950 | @subsection Defining Menus |
| 1951 | @cindex defining menus |
| 1952 | @cindex menu prompt string |
| 1953 | @cindex prompt string (of menu) |
| 1954 | |
| 1955 | A keymap acts as a menu if it has an @dfn{overall prompt string}, |
| 1956 | which is a string that appears as an element of the keymap. |
| 1957 | (@xref{Format of Keymaps}.) The string should describe the purpose of |
| 1958 | the menu's commands. Emacs displays the overall prompt string as the |
| 1959 | menu title in some cases, depending on the toolkit (if any) used for |
| 1960 | displaying menus.@footnote{It is required for menus which do not use a |
| 1961 | toolkit, e.g.@: under MS-DOS.} Keyboard menus also display the |
| 1962 | overall prompt string. |
| 1963 | |
| 1964 | The easiest way to construct a keymap with a prompt string is to |
| 1965 | specify the string as an argument when you call @code{make-keymap}, |
| 1966 | @code{make-sparse-keymap} (@pxref{Creating Keymaps}), or |
| 1967 | @code{define-prefix-command} (@pxref{Definition of |
| 1968 | define-prefix-command}). If you do not want the keymap to operate as |
| 1969 | a menu, don't specify a prompt string for it. |
| 1970 | |
| 1971 | @defun keymap-prompt keymap |
| 1972 | This function returns the overall prompt string of @var{keymap}, |
| 1973 | or @code{nil} if it has none. |
| 1974 | @end defun |
| 1975 | |
| 1976 | The menu's items are the bindings in the keymap. Each binding |
| 1977 | associates an event type to a definition, but the event types have no |
| 1978 | significance for the menu appearance. (Usually we use pseudo-events, |
| 1979 | symbols that the keyboard cannot generate, as the event types for menu |
| 1980 | item bindings.) The menu is generated entirely from the bindings that |
| 1981 | correspond in the keymap to these events. |
| 1982 | |
| 1983 | The order of items in the menu is the same as the order of bindings in |
| 1984 | the keymap. Since @code{define-key} puts new bindings at the front, you |
| 1985 | should define the menu items starting at the bottom of the menu and |
| 1986 | moving to the top, if you care about the order. When you add an item to |
| 1987 | an existing menu, you can specify its position in the menu using |
| 1988 | @code{define-key-after} (@pxref{Modifying Menus}). |
| 1989 | |
| 1990 | @menu |
| 1991 | * Simple Menu Items:: A simple kind of menu key binding, |
| 1992 | limited in capabilities. |
| 1993 | * Extended Menu Items:: More powerful menu item definitions |
| 1994 | let you specify keywords to enable |
| 1995 | various features. |
| 1996 | * Menu Separators:: Drawing a horizontal line through a menu. |
| 1997 | * Alias Menu Items:: Using command aliases in menu items. |
| 1998 | @end menu |
| 1999 | |
| 2000 | @node Simple Menu Items |
| 2001 | @subsubsection Simple Menu Items |
| 2002 | |
| 2003 | The simpler (and original) way to define a menu item is to bind some |
| 2004 | event type (it doesn't matter what event type) to a binding like this: |
| 2005 | |
| 2006 | @example |
| 2007 | (@var{item-string} . @var{real-binding}) |
| 2008 | @end example |
| 2009 | |
| 2010 | @noindent |
| 2011 | The @sc{car}, @var{item-string}, is the string to be displayed in the |
| 2012 | menu. It should be short---preferably one to three words. It should |
| 2013 | describe the action of the command it corresponds to. Note that it is |
| 2014 | not generally possible to display non-@acronym{ASCII} text in menus. It will |
| 2015 | work for keyboard menus and will work to a large extent when Emacs is |
| 2016 | built with the Gtk+ toolkit.@footnote{In this case, the text is first |
| 2017 | encoded using the @code{utf-8} coding system and then rendered by the |
| 2018 | toolkit as it sees fit.} |
| 2019 | |
| 2020 | You can also supply a second string, called the help string, as follows: |
| 2021 | |
| 2022 | @example |
| 2023 | (@var{item-string} @var{help} . @var{real-binding}) |
| 2024 | @end example |
| 2025 | |
| 2026 | @noindent |
| 2027 | @var{help} specifies a ``help-echo'' string to display while the mouse |
| 2028 | is on that item in the same way as @code{help-echo} text properties |
| 2029 | (@pxref{Help display}). |
| 2030 | |
| 2031 | As far as @code{define-key} is concerned, @var{item-string} and |
| 2032 | @var{help-string} are part of the event's binding. However, |
| 2033 | @code{lookup-key} returns just @var{real-binding}, and only |
| 2034 | @var{real-binding} is used for executing the key. |
| 2035 | |
| 2036 | If @var{real-binding} is @code{nil}, then @var{item-string} appears in |
| 2037 | the menu but cannot be selected. |
| 2038 | |
| 2039 | If @var{real-binding} is a symbol and has a non-@code{nil} |
| 2040 | @code{menu-enable} property, that property is an expression that |
| 2041 | controls whether the menu item is enabled. Every time the keymap is |
| 2042 | used to display a menu, Emacs evaluates the expression, and it enables |
| 2043 | the menu item only if the expression's value is non-@code{nil}. When a |
| 2044 | menu item is disabled, it is displayed in a ``fuzzy'' fashion, and |
| 2045 | cannot be selected. |
| 2046 | |
| 2047 | The menu bar does not recalculate which items are enabled every time you |
| 2048 | look at a menu. This is because the X toolkit requires the whole tree |
| 2049 | of menus in advance. To force recalculation of the menu bar, call |
| 2050 | @code{force-mode-line-update} (@pxref{Mode Line Format}). |
| 2051 | |
| 2052 | You've probably noticed that menu items show the equivalent keyboard key |
| 2053 | sequence (if any) to invoke the same command. To save time on |
| 2054 | recalculation, menu display caches this information in a sublist in the |
| 2055 | binding, like this: |
| 2056 | |
| 2057 | @c This line is not too long--rms. |
| 2058 | @example |
| 2059 | (@var{item-string} @r{[}@var{help}@r{]} (@var{key-binding-data}) . @var{real-binding}) |
| 2060 | @end example |
| 2061 | |
| 2062 | @noindent |
| 2063 | Don't put these sublists in the menu item yourself; menu display |
| 2064 | calculates them automatically. Don't mention keyboard equivalents in |
| 2065 | the item strings themselves, since that is redundant. |
| 2066 | |
| 2067 | @node Extended Menu Items |
| 2068 | @subsubsection Extended Menu Items |
| 2069 | @kindex menu-item |
| 2070 | |
| 2071 | An extended-format menu item is a more flexible and also cleaner |
| 2072 | alternative to the simple format. You define an event type with a |
| 2073 | binding that's a list starting with the symbol @code{menu-item}. |
| 2074 | For a non-selectable string, the binding looks like this: |
| 2075 | |
| 2076 | @example |
| 2077 | (menu-item @var{item-name}) |
| 2078 | @end example |
| 2079 | |
| 2080 | @noindent |
| 2081 | A string starting with two or more dashes specifies a separator line; |
| 2082 | see @ref{Menu Separators}. |
| 2083 | |
| 2084 | To define a real menu item which can be selected, the extended format |
| 2085 | binding looks like this: |
| 2086 | |
| 2087 | @example |
| 2088 | (menu-item @var{item-name} @var{real-binding} |
| 2089 | . @var{item-property-list}) |
| 2090 | @end example |
| 2091 | |
| 2092 | @noindent |
| 2093 | Here, @var{item-name} is an expression which evaluates to the menu item |
| 2094 | string. Thus, the string need not be a constant. The third element, |
| 2095 | @var{real-binding}, is the command to execute. The tail of the list, |
| 2096 | @var{item-property-list}, has the form of a property list which contains |
| 2097 | other information. |
| 2098 | |
| 2099 | When an equivalent keyboard key binding is cached, the extended menu |
| 2100 | item binding looks like this: |
| 2101 | |
| 2102 | @example |
| 2103 | (menu-item @var{item-name} @var{real-binding} (@var{key-binding-data}) |
| 2104 | . @var{item-property-list}) |
| 2105 | @end example |
| 2106 | |
| 2107 | Here is a table of the properties that are supported: |
| 2108 | |
| 2109 | @table @code |
| 2110 | @item :enable @var{form} |
| 2111 | The result of evaluating @var{form} determines whether the item is |
| 2112 | enabled (non-@code{nil} means yes). If the item is not enabled, |
| 2113 | you can't really click on it. |
| 2114 | |
| 2115 | @item :visible @var{form} |
| 2116 | The result of evaluating @var{form} determines whether the item should |
| 2117 | actually appear in the menu (non-@code{nil} means yes). If the item |
| 2118 | does not appear, then the menu is displayed as if this item were |
| 2119 | not defined at all. |
| 2120 | |
| 2121 | @item :help @var{help} |
| 2122 | The value of this property, @var{help}, specifies a ``help-echo'' string |
| 2123 | to display while the mouse is on that item. This is displayed in the |
| 2124 | same way as @code{help-echo} text properties (@pxref{Help display}). |
| 2125 | Note that this must be a constant string, unlike the @code{help-echo} |
| 2126 | property for text and overlays. |
| 2127 | |
| 2128 | @item :button (@var{type} . @var{selected}) |
| 2129 | This property provides a way to define radio buttons and toggle buttons. |
| 2130 | The @sc{car}, @var{type}, says which: it should be @code{:toggle} or |
| 2131 | @code{:radio}. The @sc{cdr}, @var{selected}, should be a form; the |
| 2132 | result of evaluating it says whether this button is currently selected. |
| 2133 | |
| 2134 | A @dfn{toggle} is a menu item which is labeled as either ``on'' or ``off'' |
| 2135 | according to the value of @var{selected}. The command itself should |
| 2136 | toggle @var{selected}, setting it to @code{t} if it is @code{nil}, |
| 2137 | and to @code{nil} if it is @code{t}. Here is how the menu item |
| 2138 | to toggle the @code{debug-on-error} flag is defined: |
| 2139 | |
| 2140 | @example |
| 2141 | (menu-item "Debug on Error" toggle-debug-on-error |
| 2142 | :button (:toggle |
| 2143 | . (and (boundp 'debug-on-error) |
| 2144 | debug-on-error))) |
| 2145 | @end example |
| 2146 | |
| 2147 | @noindent |
| 2148 | This works because @code{toggle-debug-on-error} is defined as a command |
| 2149 | which toggles the variable @code{debug-on-error}. |
| 2150 | |
| 2151 | @dfn{Radio buttons} are a group of menu items, in which at any time one |
| 2152 | and only one is ``selected.'' There should be a variable whose value |
| 2153 | says which one is selected at any time. The @var{selected} form for |
| 2154 | each radio button in the group should check whether the variable has the |
| 2155 | right value for selecting that button. Clicking on the button should |
| 2156 | set the variable so that the button you clicked on becomes selected. |
| 2157 | |
| 2158 | @item :key-sequence @var{key-sequence} |
| 2159 | This property specifies which key sequence is likely to be bound to the |
| 2160 | same command invoked by this menu item. If you specify the right key |
| 2161 | sequence, that makes preparing the menu for display run much faster. |
| 2162 | |
| 2163 | If you specify the wrong key sequence, it has no effect; before Emacs |
| 2164 | displays @var{key-sequence} in the menu, it verifies that |
| 2165 | @var{key-sequence} is really equivalent to this menu item. |
| 2166 | |
| 2167 | @item :key-sequence nil |
| 2168 | This property indicates that there is normally no key binding which is |
| 2169 | equivalent to this menu item. Using this property saves time in |
| 2170 | preparing the menu for display, because Emacs does not need to search |
| 2171 | the keymaps for a keyboard equivalent for this menu item. |
| 2172 | |
| 2173 | However, if the user has rebound this item's definition to a key |
| 2174 | sequence, Emacs ignores the @code{:keys} property and finds the keyboard |
| 2175 | equivalent anyway. |
| 2176 | |
| 2177 | @item :keys @var{string} |
| 2178 | This property specifies that @var{string} is the string to display |
| 2179 | as the keyboard equivalent for this menu item. You can use |
| 2180 | the @samp{\\[...]} documentation construct in @var{string}. |
| 2181 | |
| 2182 | @item :filter @var{filter-fn} |
| 2183 | This property provides a way to compute the menu item dynamically. |
| 2184 | The property value @var{filter-fn} should be a function of one argument; |
| 2185 | when it is called, its argument will be @var{real-binding}. The |
| 2186 | function should return the binding to use instead. |
| 2187 | |
| 2188 | Emacs can call this function at any time that it does redisplay or |
| 2189 | operates on menu data structures, so you should write it so it can |
| 2190 | safely be called at any time. |
| 2191 | @end table |
| 2192 | |
| 2193 | @node Menu Separators |
| 2194 | @subsubsection Menu Separators |
| 2195 | @cindex menu separators |
| 2196 | |
| 2197 | A menu separator is a kind of menu item that doesn't display any |
| 2198 | text---instead, it divides the menu into subparts with a horizontal line. |
| 2199 | A separator looks like this in the menu keymap: |
| 2200 | |
| 2201 | @example |
| 2202 | (menu-item @var{separator-type}) |
| 2203 | @end example |
| 2204 | |
| 2205 | @noindent |
| 2206 | where @var{separator-type} is a string starting with two or more dashes. |
| 2207 | |
| 2208 | In the simplest case, @var{separator-type} consists of only dashes. |
| 2209 | That specifies the default kind of separator. (For compatibility, |
| 2210 | @code{""} and @code{-} also count as separators.) |
| 2211 | |
| 2212 | Certain other values of @var{separator-type} specify a different |
| 2213 | style of separator. Here is a table of them: |
| 2214 | |
| 2215 | @table @code |
| 2216 | @item "--no-line" |
| 2217 | @itemx "--space" |
| 2218 | An extra vertical space, with no actual line. |
| 2219 | |
| 2220 | @item "--single-line" |
| 2221 | A single line in the menu's foreground color. |
| 2222 | |
| 2223 | @item "--double-line" |
| 2224 | A double line in the menu's foreground color. |
| 2225 | |
| 2226 | @item "--single-dashed-line" |
| 2227 | A single dashed line in the menu's foreground color. |
| 2228 | |
| 2229 | @item "--double-dashed-line" |
| 2230 | A double dashed line in the menu's foreground color. |
| 2231 | |
| 2232 | @item "--shadow-etched-in" |
| 2233 | A single line with a 3D sunken appearance. This is the default, |
| 2234 | used separators consisting of dashes only. |
| 2235 | |
| 2236 | @item "--shadow-etched-out" |
| 2237 | A single line with a 3D raised appearance. |
| 2238 | |
| 2239 | @item "--shadow-etched-in-dash" |
| 2240 | A single dashed line with a 3D sunken appearance. |
| 2241 | |
| 2242 | @item "--shadow-etched-out-dash" |
| 2243 | A single dashed line with a 3D raised appearance. |
| 2244 | |
| 2245 | @item "--shadow-double-etched-in" |
| 2246 | Two lines with a 3D sunken appearance. |
| 2247 | |
| 2248 | @item "--shadow-double-etched-out" |
| 2249 | Two lines with a 3D raised appearance. |
| 2250 | |
| 2251 | @item "--shadow-double-etched-in-dash" |
| 2252 | Two dashed lines with a 3D sunken appearance. |
| 2253 | |
| 2254 | @item "--shadow-double-etched-out-dash" |
| 2255 | Two dashed lines with a 3D raised appearance. |
| 2256 | @end table |
| 2257 | |
| 2258 | You can also give these names in another style, adding a colon after |
| 2259 | the double-dash and replacing each single dash with capitalization of |
| 2260 | the following word. Thus, @code{"--:singleLine"}, is equivalent to |
| 2261 | @code{"--single-line"}. |
| 2262 | |
| 2263 | Some systems and display toolkits don't really handle all of these |
| 2264 | separator types. If you use a type that isn't supported, the menu |
| 2265 | displays a similar kind of separator that is supported. |
| 2266 | |
| 2267 | @node Alias Menu Items |
| 2268 | @subsubsection Alias Menu Items |
| 2269 | |
| 2270 | Sometimes it is useful to make menu items that use the ``same'' |
| 2271 | command but with different enable conditions. The best way to do this |
| 2272 | in Emacs now is with extended menu items; before that feature existed, |
| 2273 | it could be done by defining alias commands and using them in menu |
| 2274 | items. Here's an example that makes two aliases for |
| 2275 | @code{toggle-read-only} and gives them different enable conditions: |
| 2276 | |
| 2277 | @example |
| 2278 | (defalias 'make-read-only 'toggle-read-only) |
| 2279 | (put 'make-read-only 'menu-enable '(not buffer-read-only)) |
| 2280 | (defalias 'make-writable 'toggle-read-only) |
| 2281 | (put 'make-writable 'menu-enable 'buffer-read-only) |
| 2282 | @end example |
| 2283 | |
| 2284 | When using aliases in menus, often it is useful to display the |
| 2285 | equivalent key bindings for the ``real'' command name, not the aliases |
| 2286 | (which typically don't have any key bindings except for the menu |
| 2287 | itself). To request this, give the alias symbol a non-@code{nil} |
| 2288 | @code{menu-alias} property. Thus, |
| 2289 | |
| 2290 | @example |
| 2291 | (put 'make-read-only 'menu-alias t) |
| 2292 | (put 'make-writable 'menu-alias t) |
| 2293 | @end example |
| 2294 | |
| 2295 | @noindent |
| 2296 | causes menu items for @code{make-read-only} and @code{make-writable} to |
| 2297 | show the keyboard bindings for @code{toggle-read-only}. |
| 2298 | |
| 2299 | @node Mouse Menus |
| 2300 | @subsection Menus and the Mouse |
| 2301 | |
| 2302 | The usual way to make a menu keymap produce a menu is to make it the |
| 2303 | definition of a prefix key. (A Lisp program can explicitly pop up a |
| 2304 | menu and receive the user's choice---see @ref{Pop-Up Menus}.) |
| 2305 | |
| 2306 | If the prefix key ends with a mouse event, Emacs handles the menu keymap |
| 2307 | by popping up a visible menu, so that the user can select a choice with |
| 2308 | the mouse. When the user clicks on a menu item, the event generated is |
| 2309 | whatever character or symbol has the binding that brought about that |
| 2310 | menu item. (A menu item may generate a series of events if the menu has |
| 2311 | multiple levels or comes from the menu bar.) |
| 2312 | |
| 2313 | It's often best to use a button-down event to trigger the menu. Then |
| 2314 | the user can select a menu item by releasing the button. |
| 2315 | |
| 2316 | A single keymap can appear as multiple menu panes, if you explicitly |
| 2317 | arrange for this. The way to do this is to make a keymap for each pane, |
| 2318 | then create a binding for each of those maps in the main keymap of the |
| 2319 | menu. Give each of these bindings an item string that starts with |
| 2320 | @samp{@@}. The rest of the item string becomes the name of the pane. |
| 2321 | See the file @file{lisp/mouse.el} for an example of this. Any ordinary |
| 2322 | bindings with @samp{@@}-less item strings are grouped into one pane, |
| 2323 | which appears along with the other panes explicitly created for the |
| 2324 | submaps. |
| 2325 | |
| 2326 | X toolkit menus don't have panes; instead, they can have submenus. |
| 2327 | Every nested keymap becomes a submenu, whether the item string starts |
| 2328 | with @samp{@@} or not. In a toolkit version of Emacs, the only thing |
| 2329 | special about @samp{@@} at the beginning of an item string is that the |
| 2330 | @samp{@@} doesn't appear in the menu item. |
| 2331 | |
| 2332 | Multiple keymaps that define the same menu prefix key produce |
| 2333 | separate panes or separate submenus. |
| 2334 | |
| 2335 | @node Keyboard Menus |
| 2336 | @subsection Menus and the Keyboard |
| 2337 | |
| 2338 | When a prefix key ending with a keyboard event (a character or |
| 2339 | function key) has a definition that is a menu keymap, the keymap |
| 2340 | operates as a keyboard menu; the user specifies the next event by |
| 2341 | choosing a menu item with the keyboard. |
| 2342 | |
| 2343 | Emacs displays the keyboard menu with the map's overall prompt |
| 2344 | string, followed by the alternatives (the item strings of the map's |
| 2345 | bindings), in the echo area. If the bindings don't all fit at once, |
| 2346 | the user can type @key{SPC} to see the next line of alternatives. |
| 2347 | Successive uses of @key{SPC} eventually get to the end of the menu and |
| 2348 | then cycle around to the beginning. (The variable |
| 2349 | @code{menu-prompt-more-char} specifies which character is used for |
| 2350 | this; @key{SPC} is the default.) |
| 2351 | |
| 2352 | When the user has found the desired alternative from the menu, he or |
| 2353 | she should type the corresponding character---the one whose binding is |
| 2354 | that alternative. |
| 2355 | |
| 2356 | @ignore |
| 2357 | In a menu intended for keyboard use, each menu item must clearly |
| 2358 | indicate what character to type. The best convention to use is to make |
| 2359 | the character the first letter of the item string---that is something |
| 2360 | users will understand without being told. We plan to change this; by |
| 2361 | the time you read this manual, keyboard menus may explicitly name the |
| 2362 | key for each alternative. |
| 2363 | @end ignore |
| 2364 | |
| 2365 | This way of using menus in an Emacs-like editor was inspired by the |
| 2366 | Hierarkey system. |
| 2367 | |
| 2368 | @defvar menu-prompt-more-char |
| 2369 | This variable specifies the character to use to ask to see |
| 2370 | the next line of a menu. Its initial value is 32, the code |
| 2371 | for @key{SPC}. |
| 2372 | @end defvar |
| 2373 | |
| 2374 | @node Menu Example |
| 2375 | @subsection Menu Example |
| 2376 | @cindex menu definition example |
| 2377 | |
| 2378 | Here is a complete example of defining a menu keymap. It is the |
| 2379 | definition of the @samp{Replace} submenu in the @samp{Edit} menu in |
| 2380 | the menu bar, and it uses the extended menu item format |
| 2381 | (@pxref{Extended Menu Items}). First we create the keymap, and give |
| 2382 | it a name: |
| 2383 | |
| 2384 | @smallexample |
| 2385 | (defvar menu-bar-replace-menu (make-sparse-keymap "Replace")) |
| 2386 | @end smallexample |
| 2387 | |
| 2388 | @noindent |
| 2389 | Next we define the menu items: |
| 2390 | |
| 2391 | @smallexample |
| 2392 | (define-key menu-bar-replace-menu [tags-repl-continue] |
| 2393 | '(menu-item "Continue Replace" tags-loop-continue |
| 2394 | :help "Continue last tags replace operation")) |
| 2395 | (define-key menu-bar-replace-menu [tags-repl] |
| 2396 | '(menu-item "Replace in tagged files" tags-query-replace |
| 2397 | :help "Interactively replace a regexp in all tagged files")) |
| 2398 | (define-key menu-bar-replace-menu [separator-replace-tags] |
| 2399 | '(menu-item "--")) |
| 2400 | ;; @r{@dots{}} |
| 2401 | @end smallexample |
| 2402 | |
| 2403 | @noindent |
| 2404 | Note the symbols which the bindings are ``made for''; these appear |
| 2405 | inside square brackets, in the key sequence being defined. In some |
| 2406 | cases, this symbol is the same as the command name; sometimes it is |
| 2407 | different. These symbols are treated as ``function keys,'' but they are |
| 2408 | not real function keys on the keyboard. They do not affect the |
| 2409 | functioning of the menu itself, but they are ``echoed'' in the echo area |
| 2410 | when the user selects from the menu, and they appear in the output of |
| 2411 | @code{where-is} and @code{apropos}. |
| 2412 | |
| 2413 | The menu in this example is intended for use with the mouse. If a |
| 2414 | menu is intended for use with the keyboard, that is, if it is bound to |
| 2415 | a key sequence ending with a keyboard event, then the menu items |
| 2416 | should be bound to characters or ``real'' function keys, that can be |
| 2417 | typed with the keyboard. |
| 2418 | |
| 2419 | The binding whose definition is @code{("--")} is a separator line. |
| 2420 | Like a real menu item, the separator has a key symbol, in this case |
| 2421 | @code{separator-replace-tags}. If one menu has two separators, they |
| 2422 | must have two different key symbols. |
| 2423 | |
| 2424 | Here is how we make this menu appear as an item in the parent menu: |
| 2425 | |
| 2426 | @example |
| 2427 | (define-key menu-bar-edit-menu [replace] |
| 2428 | (list 'menu-item "Replace" menu-bar-replace-menu)) |
| 2429 | @end example |
| 2430 | |
| 2431 | @noindent |
| 2432 | Note that this incorporates the submenu keymap, which is the value of |
| 2433 | the variable @code{menu-bar-replace-menu}, rather than the symbol |
| 2434 | @code{menu-bar-replace-menu} itself. Using that symbol in the parent |
| 2435 | menu item would be meaningless because @code{menu-bar-replace-menu} is |
| 2436 | not a command. |
| 2437 | |
| 2438 | If you wanted to attach the same replace menu to a mouse click, you |
| 2439 | can do it this way: |
| 2440 | |
| 2441 | @example |
| 2442 | (define-key global-map [C-S-down-mouse-1] |
| 2443 | menu-bar-replace-menu) |
| 2444 | @end example |
| 2445 | |
| 2446 | @node Menu Bar |
| 2447 | @subsection The Menu Bar |
| 2448 | @cindex menu bar |
| 2449 | |
| 2450 | Most window systems allow each frame to have a @dfn{menu bar}---a |
| 2451 | permanently displayed menu stretching horizontally across the top of the |
| 2452 | frame. The items of the menu bar are the subcommands of the fake |
| 2453 | ``function key'' @code{menu-bar}, as defined in the active keymaps. |
| 2454 | |
| 2455 | To add an item to the menu bar, invent a fake ``function key'' of your |
| 2456 | own (let's call it @var{key}), and make a binding for the key sequence |
| 2457 | @code{[menu-bar @var{key}]}. Most often, the binding is a menu keymap, |
| 2458 | so that pressing a button on the menu bar item leads to another menu. |
| 2459 | |
| 2460 | When more than one active keymap defines the same fake function key |
| 2461 | for the menu bar, the item appears just once. If the user clicks on |
| 2462 | that menu bar item, it brings up a single, combined menu containing |
| 2463 | all the subcommands of that item---the global subcommands, the local |
| 2464 | subcommands, and the minor mode subcommands. |
| 2465 | |
| 2466 | The variable @code{overriding-local-map} is normally ignored when |
| 2467 | determining the menu bar contents. That is, the menu bar is computed |
| 2468 | from the keymaps that would be active if @code{overriding-local-map} |
| 2469 | were @code{nil}. @xref{Active Keymaps}. |
| 2470 | |
| 2471 | In order for a frame to display a menu bar, its @code{menu-bar-lines} |
| 2472 | parameter must be greater than zero. Emacs uses just one line for the |
| 2473 | menu bar itself; if you specify more than one line, the other lines |
| 2474 | serve to separate the menu bar from the windows in the frame. We |
| 2475 | recommend 1 or 2 as the value of @code{menu-bar-lines}. @xref{Layout |
| 2476 | Parameters}. |
| 2477 | |
| 2478 | Here's an example of setting up a menu bar item: |
| 2479 | |
| 2480 | @example |
| 2481 | @group |
| 2482 | (modify-frame-parameters (selected-frame) |
| 2483 | '((menu-bar-lines . 2))) |
| 2484 | @end group |
| 2485 | |
| 2486 | @group |
| 2487 | ;; @r{Make a menu keymap (with a prompt string)} |
| 2488 | ;; @r{and make it the menu bar item's definition.} |
| 2489 | (define-key global-map [menu-bar words] |
| 2490 | (cons "Words" (make-sparse-keymap "Words"))) |
| 2491 | @end group |
| 2492 | |
| 2493 | @group |
| 2494 | ;; @r{Define specific subcommands in this menu.} |
| 2495 | (define-key global-map |
| 2496 | [menu-bar words forward] |
| 2497 | '("Forward word" . forward-word)) |
| 2498 | @end group |
| 2499 | @group |
| 2500 | (define-key global-map |
| 2501 | [menu-bar words backward] |
| 2502 | '("Backward word" . backward-word)) |
| 2503 | @end group |
| 2504 | @end example |
| 2505 | |
| 2506 | A local keymap can cancel a menu bar item made by the global keymap by |
| 2507 | rebinding the same fake function key with @code{undefined} as the |
| 2508 | binding. For example, this is how Dired suppresses the @samp{Edit} menu |
| 2509 | bar item: |
| 2510 | |
| 2511 | @example |
| 2512 | (define-key dired-mode-map [menu-bar edit] 'undefined) |
| 2513 | @end example |
| 2514 | |
| 2515 | @noindent |
| 2516 | @code{edit} is the fake function key used by the global map for the |
| 2517 | @samp{Edit} menu bar item. The main reason to suppress a global |
| 2518 | menu bar item is to regain space for mode-specific items. |
| 2519 | |
| 2520 | @defvar menu-bar-final-items |
| 2521 | Normally the menu bar shows global items followed by items defined by the |
| 2522 | local maps. |
| 2523 | |
| 2524 | This variable holds a list of fake function keys for items to display at |
| 2525 | the end of the menu bar rather than in normal sequence. The default |
| 2526 | value is @code{(help-menu)}; thus, the @samp{Help} menu item normally appears |
| 2527 | at the end of the menu bar, following local menu items. |
| 2528 | @end defvar |
| 2529 | |
| 2530 | @defvar menu-bar-update-hook |
| 2531 | This normal hook is run by redisplay to update the menu bar contents, |
| 2532 | before redisplaying the menu bar. You can use it to update submenus |
| 2533 | whose contents should vary. Since this hook is run frequently, we |
| 2534 | advise you to ensure that the functions it calls do not take much time |
| 2535 | in the usual case. |
| 2536 | @end defvar |
| 2537 | |
| 2538 | @node Tool Bar |
| 2539 | @subsection Tool bars |
| 2540 | @cindex tool bar |
| 2541 | |
| 2542 | A @dfn{tool bar} is a row of icons at the top of a frame, that execute |
| 2543 | commands when you click on them---in effect, a kind of graphical menu |
| 2544 | bar. |
| 2545 | |
| 2546 | The frame parameter @code{tool-bar-lines} (X resource @samp{toolBar}) |
| 2547 | controls how many lines' worth of height to reserve for the tool bar. A |
| 2548 | zero value suppresses the tool bar. If the value is nonzero, and |
| 2549 | @code{auto-resize-tool-bars} is non-@code{nil}, the tool bar expands and |
| 2550 | contracts automatically as needed to hold the specified contents. |
| 2551 | |
| 2552 | If the value of @code{auto-resize-tool-bars} is @code{grow-only}, |
| 2553 | the tool bar expands automatically, but does not contract automatically. |
| 2554 | To contract the tool bar, the user has to redraw the frame by entering |
| 2555 | @kbd{C-l}. |
| 2556 | |
| 2557 | The tool bar contents are controlled by a menu keymap attached to a |
| 2558 | fake ``function key'' called @code{tool-bar} (much like the way the menu |
| 2559 | bar is controlled). So you define a tool bar item using |
| 2560 | @code{define-key}, like this: |
| 2561 | |
| 2562 | @example |
| 2563 | (define-key global-map [tool-bar @var{key}] @var{item}) |
| 2564 | @end example |
| 2565 | |
| 2566 | @noindent |
| 2567 | where @var{key} is a fake ``function key'' to distinguish this item from |
| 2568 | other items, and @var{item} is a menu item key binding (@pxref{Extended |
| 2569 | Menu Items}), which says how to display this item and how it behaves. |
| 2570 | |
| 2571 | The usual menu keymap item properties, @code{:visible}, |
| 2572 | @code{:enable}, @code{:button}, and @code{:filter}, are useful in |
| 2573 | tool bar bindings and have their normal meanings. The @var{real-binding} |
| 2574 | in the item must be a command, not a keymap; in other words, it does not |
| 2575 | work to define a tool bar icon as a prefix key. |
| 2576 | |
| 2577 | The @code{:help} property specifies a ``help-echo'' string to display |
| 2578 | while the mouse is on that item. This is displayed in the same way as |
| 2579 | @code{help-echo} text properties (@pxref{Help display}). |
| 2580 | |
| 2581 | In addition, you should use the @code{:image} property; |
| 2582 | this is how you specify the image to display in the tool bar: |
| 2583 | |
| 2584 | @table @code |
| 2585 | @item :image @var{image} |
| 2586 | @var{images} is either a single image specification or a vector of four |
| 2587 | image specifications. If you use a vector of four, |
| 2588 | one of them is used, depending on circumstances: |
| 2589 | |
| 2590 | @table @asis |
| 2591 | @item item 0 |
| 2592 | Used when the item is enabled and selected. |
| 2593 | @item item 1 |
| 2594 | Used when the item is enabled and deselected. |
| 2595 | @item item 2 |
| 2596 | Used when the item is disabled and selected. |
| 2597 | @item item 3 |
| 2598 | Used when the item is disabled and deselected. |
| 2599 | @end table |
| 2600 | @end table |
| 2601 | |
| 2602 | If @var{image} is a single image specification, Emacs draws the tool bar |
| 2603 | button in disabled state by applying an edge-detection algorithm to the |
| 2604 | image. |
| 2605 | |
| 2606 | The default tool bar is defined so that items specific to editing do not |
| 2607 | appear for major modes whose command symbol has a @code{mode-class} |
| 2608 | property of @code{special} (@pxref{Major Mode Conventions}). Major |
| 2609 | modes may add items to the global bar by binding @code{[tool-bar |
| 2610 | @var{foo}]} in their local map. It makes sense for some major modes to |
| 2611 | replace the default tool bar items completely, since not many can be |
| 2612 | accommodated conveniently, and the default bindings make this easy by |
| 2613 | using an indirection through @code{tool-bar-map}. |
| 2614 | |
| 2615 | @defvar tool-bar-map |
| 2616 | By default, the global map binds @code{[tool-bar]} as follows: |
| 2617 | @example |
| 2618 | (global-set-key [tool-bar] |
| 2619 | '(menu-item "tool bar" ignore |
| 2620 | :filter (lambda (ignore) tool-bar-map))) |
| 2621 | @end example |
| 2622 | @noindent |
| 2623 | Thus the tool bar map is derived dynamically from the value of variable |
| 2624 | @code{tool-bar-map} and you should normally adjust the default (global) |
| 2625 | tool bar by changing that map. Major modes may replace the global bar |
| 2626 | completely by making @code{tool-bar-map} buffer-local and set to a |
| 2627 | keymap containing only the desired items. Info mode provides an |
| 2628 | example. |
| 2629 | @end defvar |
| 2630 | |
| 2631 | There are two convenience functions for defining tool bar items, as |
| 2632 | follows. |
| 2633 | |
| 2634 | @defun tool-bar-add-item icon def key &rest props |
| 2635 | This function adds an item to the tool bar by modifying |
| 2636 | @code{tool-bar-map}. The image to use is defined by @var{icon}, which |
| 2637 | is the base name of an XPM, XBM or PBM image file to be located by |
| 2638 | @code{find-image}. Given a value @samp{"exit"}, say, @file{exit.xpm}, |
| 2639 | @file{exit.pbm} and @file{exit.xbm} would be searched for in that order |
| 2640 | on a color display. On a monochrome display, the search order is |
| 2641 | @samp{.pbm}, @samp{.xbm} and @samp{.xpm}. The binding to use is the |
| 2642 | command @var{def}, and @var{key} is the fake function key symbol in the |
| 2643 | prefix keymap. The remaining arguments @var{props} are additional |
| 2644 | property list elements to add to the menu item specification. |
| 2645 | |
| 2646 | To define items in some local map, bind @code{tool-bar-map} with |
| 2647 | @code{let} around calls of this function: |
| 2648 | @example |
| 2649 | (defvar foo-tool-bar-map |
| 2650 | (let ((tool-bar-map (make-sparse-keymap))) |
| 2651 | (tool-bar-add-item @dots{}) |
| 2652 | @dots{} |
| 2653 | tool-bar-map)) |
| 2654 | @end example |
| 2655 | @end defun |
| 2656 | |
| 2657 | @defun tool-bar-add-item-from-menu command icon &optional map &rest props |
| 2658 | This function is a convenience for defining tool bar items which are |
| 2659 | consistent with existing menu bar bindings. The binding of |
| 2660 | @var{command} is looked up in the menu bar in @var{map} (default |
| 2661 | @code{global-map}) and modified to add an image specification for |
| 2662 | @var{icon}, which is found in the same way as by |
| 2663 | @code{tool-bar-add-item}. The resulting binding is then placed in |
| 2664 | @code{tool-bar-map}, so use this function only for global tool bar |
| 2665 | items. |
| 2666 | |
| 2667 | @var{map} must contain an appropriate keymap bound to |
| 2668 | @code{[menu-bar]}. The remaining arguments @var{props} are additional |
| 2669 | property list elements to add to the menu item specification. |
| 2670 | @end defun |
| 2671 | |
| 2672 | @defun tool-bar-local-item-from-menu command icon in-map &optional from-map &rest props |
| 2673 | This function is used for making non-global tool bar items. Use it |
| 2674 | like @code{tool-bar-add-item-from-menu} except that @var{in-map} |
| 2675 | specifies the local map to make the definition in. The argument |
| 2676 | @var{from-map} is like the @var{map} argument of |
| 2677 | @code{tool-bar-add-item-from-menu}. |
| 2678 | @end defun |
| 2679 | |
| 2680 | @defvar auto-resize-tool-bar |
| 2681 | If this variable is non-@code{nil}, the tool bar automatically resizes to |
| 2682 | show all defined tool bar items---but not larger than a quarter of the |
| 2683 | frame's height. |
| 2684 | |
| 2685 | If the value is @code{grow-only}, the tool bar expands automatically, |
| 2686 | but does not contract automatically. To contract the tool bar, the |
| 2687 | user has to redraw the frame by entering @kbd{C-l}. |
| 2688 | @end defvar |
| 2689 | |
| 2690 | @defvar auto-raise-tool-bar-buttons |
| 2691 | If this variable is non-@code{nil}, tool bar items display |
| 2692 | in raised form when the mouse moves over them. |
| 2693 | @end defvar |
| 2694 | |
| 2695 | @defvar tool-bar-button-margin |
| 2696 | This variable specifies an extra margin to add around tool bar items. |
| 2697 | The value is an integer, a number of pixels. The default is 4. |
| 2698 | @end defvar |
| 2699 | |
| 2700 | @defvar tool-bar-button-relief |
| 2701 | This variable specifies the shadow width for tool bar items. |
| 2702 | The value is an integer, a number of pixels. The default is 1. |
| 2703 | @end defvar |
| 2704 | |
| 2705 | @defvar tool-bar-border |
| 2706 | This variable specifies the height of the border drawn below the tool |
| 2707 | bar area. An integer value specifies height as a number of pixels. |
| 2708 | If the value is one of @code{internal-border-width} (the default) or |
| 2709 | @code{border-width}, the tool bar border height corresponds to the |
| 2710 | corresponding frame parameter. |
| 2711 | @end defvar |
| 2712 | |
| 2713 | You can define a special meaning for clicking on a tool bar item with |
| 2714 | the shift, control, meta, etc., modifiers. You do this by setting up |
| 2715 | additional items that relate to the original item through the fake |
| 2716 | function keys. Specifically, the additional items should use the |
| 2717 | modified versions of the same fake function key used to name the |
| 2718 | original item. |
| 2719 | |
| 2720 | Thus, if the original item was defined this way, |
| 2721 | |
| 2722 | @example |
| 2723 | (define-key global-map [tool-bar shell] |
| 2724 | '(menu-item "Shell" shell |
| 2725 | :image (image :type xpm :file "shell.xpm"))) |
| 2726 | @end example |
| 2727 | |
| 2728 | @noindent |
| 2729 | then here is how you can define clicking on the same tool bar image with |
| 2730 | the shift modifier: |
| 2731 | |
| 2732 | @example |
| 2733 | (define-key global-map [tool-bar S-shell] 'some-command) |
| 2734 | @end example |
| 2735 | |
| 2736 | @xref{Function Keys}, for more information about how to add modifiers to |
| 2737 | function keys. |
| 2738 | |
| 2739 | @node Modifying Menus |
| 2740 | @subsection Modifying Menus |
| 2741 | |
| 2742 | When you insert a new item in an existing menu, you probably want to |
| 2743 | put it in a particular place among the menu's existing items. If you |
| 2744 | use @code{define-key} to add the item, it normally goes at the front of |
| 2745 | the menu. To put it elsewhere in the menu, use @code{define-key-after}: |
| 2746 | |
| 2747 | @defun define-key-after map key binding &optional after |
| 2748 | Define a binding in @var{map} for @var{key}, with value @var{binding}, |
| 2749 | just like @code{define-key}, but position the binding in @var{map} after |
| 2750 | the binding for the event @var{after}. The argument @var{key} should be |
| 2751 | of length one---a vector or string with just one element. But |
| 2752 | @var{after} should be a single event type---a symbol or a character, not |
| 2753 | a sequence. The new binding goes after the binding for @var{after}. If |
| 2754 | @var{after} is @code{t} or is omitted, then the new binding goes last, at |
| 2755 | the end of the keymap. However, new bindings are added before any |
| 2756 | inherited keymap. |
| 2757 | |
| 2758 | Here is an example: |
| 2759 | |
| 2760 | @example |
| 2761 | (define-key-after my-menu [drink] |
| 2762 | '("Drink" . drink-command) 'eat) |
| 2763 | @end example |
| 2764 | |
| 2765 | @noindent |
| 2766 | makes a binding for the fake function key @key{DRINK} and puts it |
| 2767 | right after the binding for @key{EAT}. |
| 2768 | |
| 2769 | Here is how to insert an item called @samp{Work} in the @samp{Signals} |
| 2770 | menu of Shell mode, after the item @code{break}: |
| 2771 | |
| 2772 | @example |
| 2773 | (define-key-after |
| 2774 | (lookup-key shell-mode-map [menu-bar signals]) |
| 2775 | [work] '("Work" . work-command) 'break) |
| 2776 | @end example |
| 2777 | @end defun |
| 2778 | |
| 2779 | @ignore |
| 2780 | arch-tag: cfb87287-9364-4e46-9e93-6c2f7f6ae794 |
| 2781 | @end ignore |