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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
b65d8176 TTN |
2 | @c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001, |
3 | @c 2002, 2003, 2004, 2005 Free Software Foundation, Inc. | |
6bf7aab6 DL |
4 | @c See file emacs.texi for copying conditions. |
5 | @node Customization, Quitting, Amusements, Top | |
6 | @chapter Customization | |
7 | @cindex customization | |
8 | ||
9 | This chapter talks about various topics relevant to adapting the | |
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10 | behavior of Emacs in minor ways. |
11 | @iftex | |
12 | See @cite{The Emacs Lisp Reference Manual} | |
13 | @end iftex | |
14 | @ifnottex | |
15 | @xref{Top, Emacs Lisp, Emacs Lisp, elisp, The Emacs Lisp | |
16 | Reference Manual}, | |
17 | @end ifnottex | |
18 | for how to make more far-reaching changes. @xref{X Resources}, | |
e538270f | 19 | for information on using X resources to customize Emacs. |
6bf7aab6 | 20 | |
da6e9d86 | 21 | Customization that you do within Emacs normally affects only the |
110c9495 | 22 | particular Emacs session that you do it in---it does not persist |
da6e9d86 | 23 | between sessions unless you save the customization in a file such as |
17ec59da RS |
24 | @file{.emacs} or @file{.Xdefaults} that will affect future sessions. |
25 | @xref{Init File}. In the customization buffer, when you save | |
26 | customizations for future sessions, this actually works by editing | |
27 | @file{.emacs} for you. | |
6bf7aab6 | 28 | |
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29 | Another means of customization is the keyboard macro, which is a |
30 | sequence of keystrokes to be replayed with a single command. | |
31 | @xref{Keyboard Macros}, for full instruction how to record, manage, and | |
32 | replay sequences of keys. | |
33 | ||
6bf7aab6 DL |
34 | @menu |
35 | * Minor Modes:: Each minor mode is one feature you can turn on | |
36 | independently of any others. | |
5552d5a4 | 37 | * Easy Customization:: Convenient way to browse and change settings. |
6bf7aab6 DL |
38 | * Variables:: Many Emacs commands examine Emacs variables |
39 | to decide what to do; by setting variables, | |
40 | you can control their functioning. | |
6bf7aab6 DL |
41 | * Key Bindings:: The keymaps say what command each key runs. |
42 | By changing them, you can "redefine keys". | |
6bf7aab6 | 43 | * Syntax:: The syntax table controls how words and |
78b83812 | 44 | expressions are parsed. |
6bf7aab6 | 45 | * Init File:: How to write common customizations in the |
177c0ea7 | 46 | @file{.emacs} file. |
6bf7aab6 DL |
47 | @end menu |
48 | ||
49 | @node Minor Modes | |
50 | @section Minor Modes | |
51 | @cindex minor modes | |
52 | @cindex mode, minor | |
53 | ||
54 | Minor modes are optional features which you can turn on or off. For | |
55 | example, Auto Fill mode is a minor mode in which @key{SPC} breaks lines | |
56 | between words as you type. All the minor modes are independent of each | |
57 | other and of the selected major mode. Most minor modes say in the mode | |
58 | line when they are on; for example, @samp{Fill} in the mode line means | |
59 | that Auto Fill mode is on. | |
60 | ||
61 | Append @code{-mode} to the name of a minor mode to get the name of a | |
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62 | command that turns the mode on or off. Thus, the command to |
63 | enable or disable Auto Fill mode is called @code{auto-fill-mode}. These | |
6bf7aab6 DL |
64 | commands are usually invoked with @kbd{M-x}, but you can bind keys to them |
65 | if you wish. With no argument, the function turns the mode on if it was | |
66 | off and off if it was on. This is known as @dfn{toggling}. A positive | |
67 | argument always turns the mode on, and an explicit zero argument or a | |
68 | negative argument always turns it off. | |
69 | ||
da6e9d86 RS |
70 | Some minor modes are global: while enabled, they affect everything |
71 | you do in the Emacs session, in all buffers. Other minor modes are | |
72 | buffer-local; they apply only to the current buffer, so you can enable | |
73 | the mode in certain buffers and not others. | |
74 | ||
75 | For most minor modes, the command name is also the name of a | |
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76 | variable. The variable's value is non-@code{nil} if the mode is |
77 | enabled and @code{nil} if it is disabled. Some minor-mode commands | |
78 | work by just setting the variable. For example, the command | |
79 | @code{abbrev-mode} works by setting the value of @code{abbrev-mode} as | |
80 | a variable; it is this variable that directly turns Abbrev mode on and | |
81 | off. You can directly set the variable's value instead of calling the | |
82 | mode function. For other minor modes, you need to either set the | |
83 | variable through the Customize interface or call the mode function to | |
84 | correctly enable or disable the mode. To check which of these two | |
85 | possibilities applies to a given minor mode, use @kbd{C-h v} to ask | |
86 | for documentation on the variable name. | |
87 | ||
88 | For minor mode commands that work by just setting the minor mode | |
89 | variable, that variable provides a good way for Lisp programs to turn | |
90 | minor modes on and off; it is also useful in a file's local variables | |
91 | list (@pxref{File Variables}). But please think twice before setting | |
92 | minor modes with a local variables list, because most minor modes are | |
93 | a matter of user preference---other users editing the same file might | |
94 | not want the same minor modes you prefer. | |
da6e9d86 | 95 | |
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96 | The most useful buffer-local minor modes include Abbrev mode, Auto |
97 | Fill mode, Auto Save mode, Font-Lock mode, Glasses mode, ISO Accents | |
98 | mode, Outline minor mode, Overwrite mode, and Binary Overwrite mode. | |
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99 | |
100 | Abbrev mode allows you to define abbreviations that automatically expand | |
101 | as you type them. For example, @samp{amd} might expand to @samp{abbrev | |
102 | mode}. @xref{Abbrevs}, for full information. | |
103 | ||
104 | Auto Fill mode allows you to enter filled text without breaking lines | |
105 | explicitly. Emacs inserts newlines as necessary to prevent lines from | |
106 | becoming too long. @xref{Filling}. | |
107 | ||
108 | Auto Save mode causes the contents of a buffer to be saved | |
109 | periodically to reduce the amount of work you can lose in case of a | |
110 | system crash. @xref{Auto Save}. | |
111 | ||
112 | Enriched mode enables editing and saving of formatted text. | |
113 | @xref{Formatted Text}. | |
114 | ||
115 | Flyspell mode automatically highlights misspelled words. | |
116 | @xref{Spelling}. | |
117 | ||
118 | Font-Lock mode automatically highlights certain textual units found in | |
119 | programs, such as comments, strings, and function names being defined. | |
120 | This requires a window system that can display multiple fonts. | |
121 | @xref{Faces}. | |
122 | ||
6bf7aab6 DL |
123 | ISO Accents mode makes the characters @samp{`}, @samp{'}, @samp{"}, |
124 | @samp{^}, @samp{/} and @samp{~} combine with the following letter, to | |
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125 | produce an accented letter in the ISO Latin-1 character set. The |
126 | newer and more general feature of input methods more or less | |
127 | supersedes ISO Accents mode. @xref{Single-Byte Character Support}. | |
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128 | |
129 | Outline minor mode provides the same facilities as the major mode | |
130 | called Outline mode; but since it is a minor mode instead, you can | |
131 | combine it with any major mode. @xref{Outline Mode}. | |
132 | ||
133 | @cindex Overwrite mode | |
134 | @cindex mode, Overwrite | |
6bf7aab6 DL |
135 | Overwrite mode causes ordinary printing characters to replace existing |
136 | text instead of shoving it to the right. For example, if point is in | |
137 | front of the @samp{B} in @samp{FOOBAR}, then in Overwrite mode typing a | |
138 | @kbd{G} changes it to @samp{FOOGAR}, instead of producing @samp{FOOGBAR} | |
139 | as usual. In Overwrite mode, the command @kbd{C-q} inserts the next | |
140 | character whatever it may be, even if it is a digit---this gives you a | |
141 | way to insert a character instead of replacing an existing character. | |
142 | ||
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143 | @findex overwrite-mode |
144 | @kindex INSERT | |
145 | The command @code{overwrite-mode} is an exception to the rule that | |
146 | commands which toggle minor modes are normally not bound to keys: it is | |
147 | bound to the @key{INSERT} function key. This is because many other | |
148 | programs bind @key{INSERT} to similar functions. | |
149 | ||
150 | @findex binary-overwrite-mode | |
6bf7aab6 DL |
151 | Binary Overwrite mode is a variant of Overwrite mode for editing |
152 | binary files; it treats newlines and tabs like other characters, so that | |
153 | they overwrite other characters and can be overwritten by them. | |
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154 | In Binary Overwrite mode, digits after @kbd{C-q} specify an |
155 | octal character code, as usual. | |
6bf7aab6 | 156 | |
c04a2eab | 157 | Here are some useful minor modes that normally apply to all buffers |
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158 | at once. Since Line Number mode and Transient Mark mode can be |
159 | enabled or disabled just by setting the value of the minor mode | |
c04a2eab | 160 | variable, you @emph{can} set them differently for particular buffers, |
365cd965 | 161 | by explicitly making the corresponding variable local in those |
c04a2eab | 162 | buffers. @xref{Locals}. |
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163 | |
164 | Icomplete mode displays an indication of available completions when | |
165 | you are in the minibuffer and completion is active. @xref{Completion | |
166 | Options}. | |
167 | ||
168 | Line Number mode enables continuous display in the mode line of the | |
5d9dd378 | 169 | line number of point, and Column Number mode enables display of the |
6ca0edfe | 170 | column number. @xref{Mode Line}. |
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171 | |
172 | Scroll Bar mode gives each window a scroll bar (@pxref{Scroll Bars}). | |
173 | Menu Bar mode gives each frame a menu bar (@pxref{Menu Bars}). Both of | |
174 | these modes are enabled by default when you use the X Window System. | |
175 | ||
176 | In Transient Mark mode, every change in the buffer contents | |
177 | ``deactivates'' the mark, so that commands that operate on the region | |
178 | will get an error. This means you must either set the mark, or | |
179 | explicitly ``reactivate'' it, before each command that uses the region. | |
180 | The advantage of Transient Mark mode is that Emacs can display the | |
365cd965 | 181 | region highlighted. @xref{Mark}. |
6bf7aab6 | 182 | |
6bf7aab6 | 183 | @node Easy Customization |
bba2a48e RS |
184 | @section Easy Customization Interface |
185 | ||
5552d5a4 RS |
186 | @cindex settings |
187 | Emacs has many @dfn{settings} which have values that you can specify | |
188 | in order to customize various commands. Many are documented in this | |
189 | manual. Most settings are @dfn{user options}---that is to say, Lisp | |
190 | variables (@pxref{Variables})---so their names appear in the Variable | |
191 | Index (@pxref{Variable Index}). The other settings are faces and | |
192 | their attributes (@pxref{Faces}). | |
6bf7aab6 DL |
193 | |
194 | @findex customize | |
195 | @cindex customization buffer | |
5552d5a4 RS |
196 | You can browse interactively through settings and change them using |
197 | @kbd{M-x customize}. This command creates a @dfn{customization | |
198 | buffer}, which offers commands to navigate through a logically | |
199 | organized structure of the Emacs settings; you can also use it to edit | |
200 | and set their values, and to save settings permanently in your | |
201 | @file{~/.emacs} file (@pxref{Init File}). | |
bba2a48e RS |
202 | |
203 | The appearance of the example buffers in this section is typically | |
204 | different under a window system, since faces are then used to indicate | |
5552d5a4 | 205 | buttons and editable fields. |
c9f2d80c | 206 | |
6bf7aab6 | 207 | @menu |
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208 | * Groups: Customization Groups. How settings are classified in a structure. |
209 | * Browsing: Browsing Custom. Browsing and searching for settings. | |
210 | * Changing a Variable:: How to edit an option's value and set the option. | |
b4fa47b5 | 211 | * Saving Customizations:: Specifying the file for saving customizations. |
6bf7aab6 DL |
212 | * Face Customization:: How to edit the attributes of a face. |
213 | * Specific Customization:: Making a customization buffer for specific | |
89fa0de4 | 214 | variables, faces, or groups. |
4242b8d6 CY |
215 | * Custom Themes:: How to define collections of customized options |
216 | that can be loaded and unloaded together. | |
6bf7aab6 DL |
217 | @end menu |
218 | ||
219 | @node Customization Groups | |
bba2a48e | 220 | @subsection Customization Groups |
6bf7aab6 DL |
221 | @cindex customization groups |
222 | ||
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223 | For customization purposes, settings are organized into @dfn{groups} |
224 | to help you find them. Groups are collected into bigger groups, all | |
225 | the way up to a master group called @code{Emacs}. | |
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226 | |
227 | @kbd{M-x customize} creates a customization buffer that shows the | |
228 | top-level @code{Emacs} group and the second-level groups immediately | |
229 | under it. It looks like this, in part: | |
230 | ||
231 | @smallexample | |
232 | /- Emacs group: ---------------------------------------------------\ | |
6975573c | 233 | [State]: visible group members are all at standard values. |
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234 | Customization of the One True Editor. |
235 | See also [Manual]. | |
236 | ||
177c0ea7 | 237 | Editing group: [Go to Group] |
6bf7aab6 DL |
238 | Basic text editing facilities. |
239 | ||
177c0ea7 | 240 | External group: [Go to Group] |
6bf7aab6 DL |
241 | Interfacing to external utilities. |
242 | ||
243 | @var{more second-level groups} | |
244 | ||
245 | \- Emacs group end ------------------------------------------------/ | |
246 | ||
247 | @end smallexample | |
248 | ||
249 | @noindent | |
250 | This says that the buffer displays the contents of the @code{Emacs} | |
251 | group. The other groups are listed because they are its contents. But | |
252 | they are listed differently, without indentation and dashes, because | |
253 | @emph{their} contents are not included. Each group has a single-line | |
254 | documentation string; the @code{Emacs} group also has a @samp{[State]} | |
255 | line. | |
256 | ||
257 | @cindex editable fields (customization buffer) | |
5552d5a4 | 258 | @cindex buttons (customization buffer) |
6bf7aab6 | 259 | Most of the text in the customization buffer is read-only, but it |
5552d5a4 RS |
260 | typically includes some @dfn{editable fields} that you can edit. |
261 | There are also @dfn{buttons}, which do something when you @dfn{invoke} | |
262 | them. To invoke a button, either click on it with @kbd{Mouse-1}, or | |
263 | move point to it and type @key{RET}. | |
6bf7aab6 DL |
264 | |
265 | For example, the phrase @samp{[Go to Group]} that appears in a | |
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266 | second-level group is a button. Invoking it creates a new |
267 | customization buffer, which shows that group and its contents. This | |
268 | is a kind of hypertext link to another group. | |
269 | ||
270 | The @code{Emacs} group includes a few settings, but mainly it | |
271 | contains other groups, which contain more groups, which contain the | |
272 | settings. By browsing the hierarchy of groups, you will eventually | |
273 | find the feature you are interested in customizing. Then you can use | |
274 | the customization buffer to set that feature's settings. You can also | |
275 | go straight to a particular group by name, using the command @kbd{M-x | |
276 | customize-group}. | |
6bf7aab6 | 277 | |
2b8fa3be LT |
278 | @node Browsing Custom |
279 | @subsection Browsing and Searching for Options and Faces | |
6bf7aab6 | 280 | @findex customize-browse |
5552d5a4 RS |
281 | |
282 | @kbd{M-x customize-browse} is another way to browse the available | |
283 | settings. This command creates a special customization buffer which | |
284 | shows only the names of groups and settings, and puts them in a | |
285 | structure. | |
6bf7aab6 DL |
286 | |
287 | In this buffer, you can show the contents of a group by invoking | |
288 | @samp{[+]}. When the group contents are visible, this button changes to | |
289 | @samp{[-]}; invoking that hides the group contents. | |
290 | ||
5552d5a4 RS |
291 | Each setting in this buffer has a button which says @samp{[Group]}, |
292 | @samp{[Option]} or @samp{[Face]}. Invoking this button creates an | |
293 | ordinary customization buffer showing just that group and its | |
294 | contents, just that user option, or just that face. This is the way | |
295 | to change settings that you find with @kbd{M-x customize-browse}. | |
6bf7aab6 | 296 | |
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297 | If you can guess part of the name of the settings you are interested |
298 | in, @kbd{M-x customize-apropos} is another way to search for settings. | |
299 | However, unlike @code{customize} and @code{customize-browse}, | |
300 | @code{customize-apropos} can only find groups and settings that are | |
301 | loaded in the current Emacs session. @xref{Specific Customization,, | |
302 | Customizing Specific Items}. | |
2b8fa3be | 303 | |
89fa0de4 RS |
304 | @node Changing a Variable |
305 | @subsection Changing a Variable | |
6bf7aab6 | 306 | |
5552d5a4 RS |
307 | Here is an example of what a variable (a user option) looks like in |
308 | the customization buffer: | |
6bf7aab6 DL |
309 | |
310 | @smallexample | |
365cd965 LT |
311 | Kill Ring Max: [Hide Value] 60 |
312 | [State]: STANDARD. | |
6bf7aab6 DL |
313 | Maximum length of kill ring before oldest elements are thrown away. |
314 | @end smallexample | |
315 | ||
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316 | The text following @samp{[Hide Value]}, @samp{60} in this case, indicates |
317 | the current value of the variable. If you see @samp{[Show Value]} instead of | |
318 | @samp{[Hide Value]}, it means that the value is hidden; the customization | |
6bf7aab6 | 319 | buffer initially hides values that take up several lines. Invoke |
365cd965 | 320 | @samp{[Show Value]} to show the value. |
6bf7aab6 | 321 | |
5552d5a4 RS |
322 | The line after the variable name indicates the @dfn{customization |
323 | state} of the variable: in the example above, it says you have not | |
324 | changed the option yet. The @samp{[State]} button at the beginning of | |
325 | this line gives you a menu of various operations for customizing the | |
326 | variable. | |
6bf7aab6 DL |
327 | |
328 | The line after the @samp{[State]} line displays the beginning of the | |
89fa0de4 | 329 | variable's documentation string. If there are more lines of |
5552d5a4 RS |
330 | documentation, this line ends with a @samp{[More]} button; invoke that |
331 | to show the full documentation string. | |
6bf7aab6 | 332 | |
5552d5a4 RS |
333 | To enter a new value for @samp{Kill Ring Max}, move point to the |
334 | value and edit it textually. For example, you can type @kbd{M-d}, | |
335 | then insert another number. As you begin to alter the text, you will | |
336 | see the @samp{[State]} line change to say that you have edited the | |
337 | value: | |
6bf7aab6 DL |
338 | |
339 | @smallexample | |
365cd965 LT |
340 | [State]: EDITED, shown value does not take effect until you set or @r{@dots{}} |
341 | save it. | |
6bf7aab6 DL |
342 | @end smallexample |
343 | ||
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344 | @cindex settings, how to set |
345 | Editing the value does not actually set the variable. To do that, | |
346 | you must @dfn{set} the variable. To do this, invoke the | |
347 | @samp{[State]} button and choose @samp{Set for Current Session}. | |
6bf7aab6 | 348 | |
89fa0de4 | 349 | The state of the variable changes visibly when you set it: |
6bf7aab6 DL |
350 | |
351 | @smallexample | |
365cd965 | 352 | [State]: SET for current session only. |
6bf7aab6 DL |
353 | @end smallexample |
354 | ||
355 | You don't have to worry about specifying a value that is not valid; | |
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356 | the @samp{Set for Current Session} operation checks for validity and |
357 | will not install an unacceptable value. | |
6bf7aab6 DL |
358 | |
359 | @kindex M-TAB @r{(customization buffer)} | |
360 | @findex widget-complete | |
5552d5a4 | 361 | While editing a field that is a file name, directory name, |
ad5e19b3 RS |
362 | command name, or anything else for which completion is defined, you |
363 | can type @kbd{M-@key{TAB}} (@code{widget-complete}) to do completion. | |
364 | (@kbd{@key{ESC} @key{TAB}} and @kbd{C-M-i} do the same thing.) | |
6bf7aab6 | 365 | |
89fa0de4 | 366 | Some variables have a small fixed set of possible legitimate values. |
5552d5a4 RS |
367 | These variables don't let you edit the value textually. Instead, a |
368 | @samp{[Value Menu]} button appears before the value; invoke this | |
369 | button to change the value. For a boolean ``on or off'' value, the | |
370 | button says @samp{[Toggle]}, and it changes to the other value. | |
371 | @samp{[Value Menu]} and @samp{[Toggle]} simply edit the buffer; the | |
372 | changes take real effect when you use the @samp{Set for Current | |
373 | Session} operation. | |
6bf7aab6 | 374 | |
89fa0de4 | 375 | Some variables have values with complex structure. For example, the |
c9f2d80c DL |
376 | value of @code{file-coding-system-alist} is an association list. Here |
377 | is how it appears in the customization buffer: | |
6bf7aab6 DL |
378 | |
379 | @smallexample | |
365cd965 | 380 | File Coding System Alist: [Hide Value] |
c9f2d80c DL |
381 | [INS] [DEL] File regexp: \.elc\' |
382 | Choice: [Value Menu] Encoding/decoding pair: | |
383 | Decoding: emacs-mule | |
384 | Encoding: emacs-mule | |
385 | [INS] [DEL] File regexp: \(\`\|/\)loaddefs.el\' | |
386 | Choice: [Value Menu] Encoding/decoding pair: | |
6b46232e RS |
387 | Decoding: raw-text |
388 | Encoding: raw-text-unix | |
c9f2d80c DL |
389 | [INS] [DEL] File regexp: \.tar\' |
390 | Choice: [Value Menu] Encoding/decoding pair: | |
391 | Decoding: no-conversion | |
392 | Encoding: no-conversion | |
393 | [INS] [DEL] File regexp: | |
394 | Choice: [Value Menu] Encoding/decoding pair: | |
395 | Decoding: undecided | |
396 | Encoding: nil | |
5d9dd378 | 397 | [INS] |
365cd965 LT |
398 | [State]: STANDARD. |
399 | Alist to decide a coding system to use for a file I/O @r{@dots{}} | |
400 | operation. [Hide Rest] | |
5d9dd378 RS |
401 | The format is ((PATTERN . VAL) ...), |
402 | where PATTERN is a regular expression matching a file name, | |
403 | @r{[@dots{}more lines of documentation@dots{}]} | |
6bf7aab6 DL |
404 | @end smallexample |
405 | ||
406 | @noindent | |
5d9dd378 | 407 | Each association in the list appears on four lines, with several |
5552d5a4 | 408 | editable fields and/or buttons. You can edit the regexps and coding |
5d9dd378 | 409 | systems using ordinary editing commands. You can also invoke |
5552d5a4 RS |
410 | @samp{[Value Menu]} to switch to a different kind of value---for |
411 | instance, to specify a function instead of a pair of coding systems. | |
5d9dd378 RS |
412 | |
413 | To delete an association from the list, invoke the @samp{[DEL]} button | |
414 | for that item. To add an association, invoke @samp{[INS]} at the | |
415 | position where you want to add it. There is an @samp{[INS]} button | |
416 | between each pair of association, another at the beginning and another | |
417 | at the end, so you can add the new association at any position in the | |
418 | list. | |
6bf7aab6 DL |
419 | |
420 | @kindex TAB @r{(customization buffer)} | |
421 | @kindex S-TAB @r{(customization buffer)} | |
422 | @findex widget-forward | |
423 | @findex widget-backward | |
5552d5a4 RS |
424 | Two special commands, @key{TAB} and @kbd{S-@key{TAB}}, are useful |
425 | for moving through the customization buffer. @key{TAB} | |
426 | (@code{widget-forward}) moves forward to the next button or editable | |
427 | field; @kbd{S-@key{TAB}} (@code{widget-backward}) moves backward to | |
428 | the previous button or editable field. | |
6bf7aab6 DL |
429 | |
430 | Typing @key{RET} on an editable field also moves forward, just like | |
5d9dd378 RS |
431 | @key{TAB}. We set it up this way because people often type @key{RET} |
432 | when they are finished editing a field. To insert a newline within an | |
433 | editable field, use @kbd{C-o} or @kbd{C-q C-j}. | |
6bf7aab6 | 434 | |
5552d5a4 RS |
435 | @cindex saving a setting |
436 | @cindex settings, how to save | |
89fa0de4 | 437 | Setting the variable changes its value in the current Emacs session; |
88ca5bbf | 438 | @dfn{saving} the value changes it for future sessions as well. To |
89fa0de4 | 439 | save the variable, invoke @samp{[State]} and select the @samp{Save for |
88ca5bbf | 440 | Future Sessions} operation. This works by writing code so as to set |
89fa0de4 | 441 | the variable again, each time you start Emacs (@pxref{Saving |
88ca5bbf | 442 | Customizations}). |
f4220fcd | 443 | |
89fa0de4 | 444 | You can also restore the variable to its standard value by invoking |
88ca5bbf | 445 | @samp{[State]} and selecting the @samp{Erase Customization} operation. |
365cd965 | 446 | There are actually four reset operations: |
6bf7aab6 DL |
447 | |
448 | @table @samp | |
6975573c | 449 | @item Undo Edits |
89fa0de4 | 450 | If you have made some modifications and not yet set the variable, |
6bf7aab6 DL |
451 | this restores the text in the customization buffer to match |
452 | the actual value. | |
453 | ||
454 | @item Reset to Saved | |
89fa0de4 | 455 | This restores the value of the variable to the last saved value, |
6bf7aab6 DL |
456 | and updates the text accordingly. |
457 | ||
0a7790e0 | 458 | @item Erase Customization |
89fa0de4 | 459 | This sets the variable to its standard value, and updates the text |
5552d5a4 | 460 | accordingly. This also eliminates any saved value for the variable, |
6bf7aab6 | 461 | so that you will get the standard value in future Emacs sessions. |
88ca5bbf | 462 | |
6975573c | 463 | @item Set to Backup Value |
89fa0de4 RS |
464 | This sets the variable to a previous value that was set in the |
465 | customization buffer in this session. If you customize a variable | |
bba2a48e | 466 | and then reset it, which discards the customized value, |
88ca5bbf | 467 | you can get the customized value back again with this operation. |
6bf7aab6 DL |
468 | @end table |
469 | ||
0a7790e0 | 470 | @cindex comments on customized options |
5d9dd378 RS |
471 | Sometimes it is useful to record a comment about a specific |
472 | customization. Use the @samp{Add Comment} item from the | |
473 | @samp{[State]} menu to create a field for entering the comment. The | |
474 | comment you enter will be saved, and displayed again if you again view | |
89fa0de4 | 475 | the same variable in a customization buffer, even in another session. |
0a7790e0 | 476 | |
6bf7aab6 | 477 | The state of a group indicates whether anything in that group has been |
365cd965 | 478 | edited, set or saved. |
6bf7aab6 | 479 | |
5552d5a4 | 480 | Near the top of the customization buffer there are two lines of buttons: |
6bf7aab6 DL |
481 | |
482 | @smallexample | |
483 | [Set for Current Session] [Save for Future Sessions] | |
6975573c | 484 | [Undo Edits] [Reset to Saved] [Erase Customization] [Finish] |
6bf7aab6 DL |
485 | @end smallexample |
486 | ||
bc49c316 | 487 | @vindex custom-buffer-done-function |
6bf7aab6 | 488 | @noindent |
0a7790e0 | 489 | Invoking @samp{[Finish]} either buries or kills this customization |
bc49c316 | 490 | buffer according to the setting of the option |
365cd965 | 491 | @code{custom-buffer-done-kill}; the default is to bury the buffer. |
5552d5a4 RS |
492 | Each of the other buttons performs an operation---set, save or |
493 | reset---on each of the settings in the buffer that could meaningfully | |
494 | be set, saved or reset. They do not operate on settings whose values | |
495 | are hidden, nor on subgroups not visible in the buffer. | |
6bf7aab6 | 496 | |
88ca5bbf | 497 | @node Saving Customizations |
bba2a48e | 498 | @subsection Saving Customizations |
88ca5bbf RS |
499 | |
500 | @vindex custom-file | |
501 | The customization buffer normally saves customizations in | |
502 | @file{~/.emacs}. If you wish, you can save customizations in another | |
503 | file instead. To make this work, your @file{~/.emacs} should set | |
d3675605 RS |
504 | @code{custom-file} to the name of that file. Then you should load the |
505 | file by calling @code{load}. For example: | |
88ca5bbf RS |
506 | |
507 | @example | |
ed930870 LT |
508 | (setq custom-file "~/.emacs-custom.el") |
509 | (load custom-file) | |
88ca5bbf RS |
510 | @end example |
511 | ||
22667510 LT |
512 | You can also use @code{custom-file} to specify different |
513 | customization files for different Emacs versions, like this: | |
88ca5bbf RS |
514 | |
515 | @example | |
22667510 LT |
516 | (cond ((< emacs-major-version 21) |
517 | ;; @r{Emacs 20 customization.} | |
518 | (setq custom-file "~/.custom-20.el")) | |
519 | ((and (= emacs-major-version 21) (< emacs-minor-version 4)) | |
520 | ;; @r{Emacs 21 customization, before version 21.4.} | |
521 | (setq custom-file "~/.custom-21.el")) | |
bf247b6e | 522 | ((< emacs-major-version 22) |
22667510 | 523 | ;; @r{Emacs version 21.4 or later.} |
bf247b6e KS |
524 | (setq custom-file "~/.custom-21.4.el")) |
525 | (t | |
526 | ;; @r{Emacs version 22.1 or later.} | |
527 | (setq custom-file "~/.custom-22.el"))) | |
22667510 LT |
528 | |
529 | (load custom-file) | |
88ca5bbf RS |
530 | @end example |
531 | ||
532 | If Emacs was invoked with the @option{-q} or @option{--no-init-file} | |
533 | options (@pxref{Initial Options}), it will not let you save your | |
534 | customizations in your @file{~/.emacs} init file. This is because | |
535 | saving customizations from such a session would wipe out all the other | |
536 | customizations you might have on your init file. | |
537 | ||
6bf7aab6 | 538 | @node Face Customization |
bba2a48e | 539 | @subsection Customizing Faces |
6bf7aab6 DL |
540 | @cindex customizing faces |
541 | @cindex bold font | |
542 | @cindex italic font | |
543 | @cindex fonts and faces | |
544 | ||
89fa0de4 RS |
545 | In addition to variables, some customization groups also include |
546 | faces. When you show the contents of a group, both the variables and | |
6bf7aab6 DL |
547 | the faces in the group appear in the customization buffer. Here is an |
548 | example of how a face looks: | |
549 | ||
550 | @smallexample | |
365cd965 LT |
551 | Custom Changed Face:(sample) [Hide Face] |
552 | [State]: STANDARD. | |
6bdcb1dc | 553 | Face used when the customize item has been changed. |
365cd965 | 554 | Parent groups: [Custom Magic Faces] |
6bdcb1dc MB |
555 | Attributes: [ ] Font Family: * |
556 | [ ] Width: * | |
557 | [ ] Height: * | |
558 | [ ] Weight: * | |
559 | [ ] Slant: * | |
560 | [ ] Underline: * | |
561 | [ ] Overline: * | |
562 | [ ] Strike-through: * | |
563 | [ ] Box around text: * | |
564 | [ ] Inverse-video: * | |
565 | [X] Foreground: white (sample) | |
566 | [X] Background: blue (sample) | |
567 | [ ] Stipple: * | |
568 | [ ] Inherit: * | |
6bf7aab6 DL |
569 | @end smallexample |
570 | ||
5552d5a4 | 571 | Each face attribute has its own line. The @samp{[@var{x}]} button |
6bf7aab6 | 572 | before the attribute name indicates whether the attribute is |
5552d5a4 RS |
573 | @dfn{enabled}; @samp{[X]} means that it's enabled, and @samp{[ ]} |
574 | means that it's disabled. You can enable or disable the attribute by | |
575 | clicking that button. When the attribute is enabled, you can change | |
576 | the attribute value in the usual ways. | |
6bf7aab6 | 577 | |
ee264870 | 578 | For the colors, you can specify a color name (use @kbd{M-x |
365cd965 | 579 | list-colors-display} for a list of them) or a hexadecimal color |
ee264870 RS |
580 | specification of the form @samp{#@var{rr}@var{gg}@var{bb}}. |
581 | (@samp{#000000} is black, @samp{#ff0000} is red, @samp{#00ff00} is | |
582 | green, @samp{#0000ff} is blue, and @samp{#ffffff} is white.) On a | |
583 | black-and-white display, the colors you can use for the background are | |
584 | @samp{black}, @samp{white}, @samp{gray}, @samp{gray1}, and | |
585 | @samp{gray3}. Emacs supports these shades of gray by using background | |
586 | stipple patterns instead of a color. | |
6bf7aab6 DL |
587 | |
588 | Setting, saving and resetting a face work like the same operations for | |
89fa0de4 | 589 | variables (@pxref{Changing a Variable}). |
6bf7aab6 DL |
590 | |
591 | A face can specify different appearances for different types of | |
592 | display. For example, a face can make text red on a color display, but | |
593 | use a bold font on a monochrome display. To specify multiple | |
6975573c LT |
594 | appearances for a face, select @samp{For All Kinds of Displays} in the |
595 | menu you get from invoking @samp{[State]}. | |
6bf7aab6 DL |
596 | |
597 | @findex modify-face | |
598 | Another more basic way to set the attributes of a specific face is | |
599 | with @kbd{M-x modify-face}. This command reads the name of a face, then | |
600 | reads the attributes one by one. For the color and stipple attributes, | |
601 | the attribute's current value is the default---type just @key{RET} if | |
602 | you don't want to change that attribute. Type @samp{none} if you want | |
603 | to clear out the attribute. | |
604 | ||
605 | @node Specific Customization | |
bba2a48e | 606 | @subsection Customizing Specific Items |
6bf7aab6 | 607 | |
5552d5a4 RS |
608 | Instead of finding the setting you want to change by navigating the |
609 | structure of groups, here are other ways to specify the settings that | |
610 | you want to customize. | |
6bf7aab6 DL |
611 | |
612 | @table @kbd | |
89fa0de4 RS |
613 | @item M-x customize-variable @key{RET} @var{variable} @key{RET} |
614 | Set up a customization buffer with just one variable, @var{variable}. | |
6bf7aab6 DL |
615 | @item M-x customize-face @key{RET} @var{face} @key{RET} |
616 | Set up a customization buffer with just one face, @var{face}. | |
617 | @item M-x customize-group @key{RET} @var{group} @key{RET} | |
618 | Set up a customization buffer with just one group, @var{group}. | |
619 | @item M-x customize-apropos @key{RET} @var{regexp} @key{RET} | |
5552d5a4 RS |
620 | Set up a customization buffer with all the settings and groups that |
621 | match @var{regexp}. | |
6bf7aab6 | 622 | @item M-x customize-changed-options @key{RET} @var{version} @key{RET} |
5552d5a4 | 623 | Set up a customization buffer with all the settings and groups |
6bf7aab6 | 624 | whose meaning has changed since Emacs version @var{version}. |
177c0ea7 | 625 | @item M-x customize-saved |
5552d5a4 | 626 | Set up a customization buffer containing all settings that you |
6bf7aab6 DL |
627 | have saved with customization buffers. |
628 | @item M-x customize-customized | |
5552d5a4 RS |
629 | Set up a customization buffer containing all settings that you have |
630 | customized but not saved. | |
6bf7aab6 DL |
631 | @end table |
632 | ||
89fa0de4 RS |
633 | @findex customize-variable |
634 | If you want to alter a particular variable with the customization | |
635 | buffer, and you know its name, you can use the command @kbd{M-x | |
636 | customize-variable} and specify the variable name. This sets up the | |
637 | customization buffer with just one variable---the one that you asked | |
638 | for. Editing, setting and saving the value work as described above, | |
5552d5a4 RS |
639 | but only for the specified variable. Minibuffer completion is handy |
640 | if you only know part of the name. However, this command can only see | |
2b8fa3be | 641 | options that have been loaded in the current Emacs session. |
6bf7aab6 DL |
642 | |
643 | @findex customize-face | |
644 | Likewise, you can modify a specific face, chosen by name, using | |
0a5ec0fe RS |
645 | @kbd{M-x customize-face}. By default it operates on the face used |
646 | on the character after point. | |
6bf7aab6 DL |
647 | |
648 | @findex customize-group | |
649 | You can also set up the customization buffer with a specific group, | |
650 | using @kbd{M-x customize-group}. The immediate contents of the chosen | |
5552d5a4 | 651 | group, including variables, faces, and other groups, all appear |
2b8fa3be LT |
652 | as well (even if not already loaded). However, the subgroups' own |
653 | contents are not included. | |
6bf7aab6 DL |
654 | |
655 | @findex customize-apropos | |
656 | To control more precisely what to customize, you can use @kbd{M-x | |
5552d5a4 RS |
657 | customize-apropos}. You specify a regular expression as argument; |
658 | then all @emph{loaded} settings and groups whose names match this | |
2b8fa3be | 659 | regular expression are set up in the customization buffer. If you |
5552d5a4 RS |
660 | specify an empty regular expression, this includes @emph{all} loaded |
661 | groups and settings---which takes a long time to set up. | |
6bf7aab6 | 662 | |
5552d5a4 | 663 | @findex customize-changed |
6bf7aab6 | 664 | When you upgrade to a new Emacs version, you might want to customize |
5552d5a4 RS |
665 | new settings and settings whose meanings or default values have |
666 | changed. To do this, use @kbd{M-x customize-changed} and | |
667 | specify a previous Emacs version number using the minibuffer. It | |
668 | creates a customization buffer which shows all the settings and groups | |
669 | whose definitions have been changed since the specified version, loading | |
670 | them if necessary. | |
6bf7aab6 DL |
671 | |
672 | @findex customize-saved | |
673 | @findex customize-customized | |
5552d5a4 RS |
674 | If you change settings and then decide the change was a mistake, you |
675 | can use two special commands to revisit your previous changes. Use | |
676 | @kbd{M-x customize-saved} to look at the settings that you have saved. | |
677 | Use @kbd{M-x customize-customized} to look at the settings that you | |
678 | have set but not saved. | |
6bf7aab6 | 679 | |
4242b8d6 CY |
680 | @node Custom Themes |
681 | @subsection Customization Themes | |
682 | @cindex custom themes | |
683 | ||
5552d5a4 RS |
684 | @dfn{Custom themes} are collections of settings that can be enabled |
685 | or disabled as a unit. You can use Custom themes to switch quickly | |
686 | and easily between various collections of settings, and to transfer | |
687 | such collections from one computer to another. | |
4242b8d6 CY |
688 | |
689 | @findex customize-create-theme | |
31869a0f CY |
690 | To define a Custom theme, use @kbd{M-x customize-create-theme}, |
691 | which brings up a buffer named @samp{*New Custom Theme*}. At the top | |
692 | of the buffer is an editable field where you can specify the name of | |
693 | the theme. Click on the button labelled @samp{Insert Variable} to add | |
694 | a variable to the theme, and click on @samp{Insert Face} to add a | |
695 | face. You can edit these values in the @samp{*New Custom Theme*} | |
696 | buffer like in an ordinary Customize buffer. To remove an option from | |
697 | the theme, click on its @samp{State} button and select @samp{Delete}. | |
4242b8d6 CY |
698 | |
699 | @vindex custom-theme-directory | |
5f7543f8 CY |
700 | After adding the desired options, click on @samp{Save Theme} to save |
701 | the Custom theme. This writes the theme definition to a file | |
702 | @file{@var{foo}-theme.el} (where @var{foo} is the theme name you | |
703 | supplied), in the directory @file{~/.emacs.d/}. You can specify the | |
704 | directory by setting @code{custom-theme-directory}. | |
705 | ||
706 | You can view and edit the settings of a previously-defined theme by | |
707 | clicking on @samp{Visit Theme} and specifying the theme name. You can | |
708 | also import the variables and faces that you have set using Customize | |
31869a0f | 709 | by visiting the ``special'' theme named @samp{user}. This theme, which |
5f7543f8 CY |
710 | records all the options that you set in the ordinary customization |
711 | buffer, is always enabled, and always takes precedence over all other | |
712 | enabled Custom themes. Additionally, the @samp{user} theme is | |
713 | recorded in your @file{.emacs} file, rather than a | |
714 | @file{user-theme.el} file. | |
715 | ||
716 | @vindex custom-enabled-themes | |
717 | Once you have defined a Custom theme, you can use it by customizing | |
718 | the variable @code{custom-enabled-themes}. This is a list of Custom | |
719 | themes that are @dfn{enabled}, or put into effect. If you set | |
720 | @code{custom-enabled-themes} using the Customize interface, the theme | |
721 | definitions are automatically loaded from the theme files, if they | |
722 | aren't already. If you save the value of @code{custom-enabled-themes} | |
723 | for future Emacs sessions, those Custom themes will be enabled | |
724 | whenever Emacs is started up. | |
725 | ||
726 | If two enabled themes specify different values for an option, the | |
727 | theme occurring earlier in @code{custom-enabled-themes} takes effect. | |
4242b8d6 CY |
728 | |
729 | @findex load-theme | |
730 | @findex enable-theme | |
731 | @findex disable-theme | |
8a176e64 RS |
732 | You can temporarily enable a Custom theme with @kbd{M-x |
733 | enable-theme}. This prompts for a theme name in the minibuffer, loads | |
734 | the theme from the theme file if necessary, and enables the theme. | |
735 | You can @dfn{disabled} any enabled theme with the command @kbd{M-x | |
736 | disable-theme}; this returns the options specified in the theme to | |
737 | their original values. To re-enable the theme, type @kbd{M-x | |
738 | enable-theme} again. If a theme file is changed during your Emacs | |
739 | session, you can reload it by typing @kbd{M-x load-theme}. (This also | |
740 | enables the theme.) | |
4242b8d6 | 741 | |
bba2a48e RS |
742 | @node Variables |
743 | @section Variables | |
744 | @cindex variable | |
745 | @cindex option, user | |
746 | @cindex user option | |
747 | ||
748 | A @dfn{variable} is a Lisp symbol which has a value. The symbol's | |
749 | name is also called the name of the variable. A variable name can | |
750 | contain any characters that can appear in a file, but conventionally | |
751 | variable names consist of words separated by hyphens. A variable can | |
752 | have a documentation string which describes what kind of value it should | |
753 | have and how the value will be used. | |
754 | ||
5552d5a4 RS |
755 | Emacs Lisp allows any variable (with a few exceptions) to have any |
756 | kind of value, but most variables that Emacs uses need a value of a | |
757 | certain type. Often the value should always be a string, or should | |
758 | always be a number. Sometimes we say that a certain feature is turned | |
759 | on if a variable is ``non-@code{nil},'' meaning that if the variable's | |
760 | value is @code{nil}, the feature is off, but the feature is on for | |
761 | @emph{any} other value. The conventional value to use to turn on the | |
762 | feature---since you have to pick one particular value when you set the | |
763 | variable---is @code{t}. | |
bba2a48e RS |
764 | |
765 | Emacs uses many Lisp variables for internal record keeping, but the | |
5552d5a4 RS |
766 | most interesting variables for a non-programmer user are those meant |
767 | for users to change---the @dfn{user options}. | |
768 | ||
769 | Each user option that you can set with the customization buffer is | |
770 | in fact a Lisp variable. Emacs does not (usually) change the values | |
771 | of these variables; instead, you set the values, and thereby alter and | |
772 | control the behavior of certain Emacs commands. Use of the | |
773 | customization buffer is explained above (@pxref{Easy Customization}); | |
774 | here we describe other aspects of Emacs variables. | |
bba2a48e RS |
775 | |
776 | @menu | |
777 | * Examining:: Examining or setting one variable's value. | |
778 | * Hooks:: Hook variables let you specify programs for parts | |
779 | of Emacs to run on particular occasions. | |
780 | * Locals:: Per-buffer values of variables. | |
781 | * File Variables:: How files can specify variable values. | |
782 | @end menu | |
783 | ||
784 | @node Examining | |
785 | @subsection Examining and Setting Variables | |
786 | @cindex setting variables | |
787 | ||
788 | @table @kbd | |
789 | @item C-h v @var{var} @key{RET} | |
790 | Display the value and documentation of variable @var{var} | |
791 | (@code{describe-variable}). | |
792 | @item M-x set-variable @key{RET} @var{var} @key{RET} @var{value} @key{RET} | |
793 | Change the value of variable @var{var} to @var{value}. | |
794 | @end table | |
795 | ||
796 | To examine the value of a single variable, use @kbd{C-h v} | |
797 | (@code{describe-variable}), which reads a variable name using the | |
798 | minibuffer, with completion. It displays both the value and the | |
799 | documentation of the variable. For example, | |
800 | ||
801 | @example | |
802 | C-h v fill-column @key{RET} | |
803 | @end example | |
804 | ||
805 | @noindent | |
806 | displays something like this: | |
807 | ||
808 | @smallexample | |
809 | fill-column's value is 70 | |
810 | ||
811 | Documentation: | |
812 | *Column beyond which automatic line-wrapping should happen. | |
813 | Automatically becomes buffer-local when set in any fashion. | |
814 | @end smallexample | |
815 | ||
816 | @noindent | |
817 | The star at the beginning of the documentation indicates that this | |
818 | variable is a user option. @kbd{C-h v} is not restricted to user | |
819 | options; it allows any variable name. | |
820 | ||
821 | @findex set-variable | |
89fa0de4 RS |
822 | The most convenient way to set a specific user option variable is |
823 | with @kbd{M-x set-variable}. This reads the variable name with the | |
824 | minibuffer (with completion), and then reads a Lisp expression for the | |
564dd0f2 JL |
825 | new value using the minibuffer a second time (you can insert the old |
826 | value into the minibuffer for editing via @kbd{M-n}). For example, | |
bba2a48e RS |
827 | |
828 | @example | |
829 | M-x set-variable @key{RET} fill-column @key{RET} 75 @key{RET} | |
830 | @end example | |
831 | ||
832 | @noindent | |
833 | sets @code{fill-column} to 75. | |
834 | ||
835 | @kbd{M-x set-variable} is limited to user option variables, but you can | |
836 | set any variable with a Lisp expression, using the function @code{setq}. | |
837 | Here is a @code{setq} expression to set @code{fill-column}: | |
838 | ||
839 | @example | |
840 | (setq fill-column 75) | |
841 | @end example | |
842 | ||
843 | To execute an expression like this one, go to the @samp{*scratch*} | |
844 | buffer, type in the expression, and then type @kbd{C-j}. @xref{Lisp | |
845 | Interaction}. | |
846 | ||
847 | Setting variables, like all means of customizing Emacs except where | |
af1b4255 RS |
848 | otherwise stated, affects only the current Emacs session. The only |
849 | way to alter the variable in future sessions is to put something in | |
850 | the @file{~/.emacs} file to set it those sessions (@pxref{Init File}). | |
bba2a48e | 851 | |
6bf7aab6 DL |
852 | @node Hooks |
853 | @subsection Hooks | |
854 | @cindex hook | |
6bf7aab6 DL |
855 | @cindex running a hook |
856 | ||
857 | @dfn{Hooks} are an important mechanism for customization of Emacs. A | |
858 | hook is a Lisp variable which holds a list of functions, to be called on | |
859 | some well-defined occasion. (This is called @dfn{running the hook}.) | |
860 | The individual functions in the list are called the @dfn{hook functions} | |
861 | of the hook. With rare exceptions, hooks in Emacs are empty when Emacs | |
862 | starts up, so the only hook functions in any given hook are the ones you | |
863 | explicitly put there as customization. | |
864 | ||
865 | Most major modes run one or more @dfn{mode hooks} as the last step of | |
866 | initialization. This makes it easy for you to customize the behavior of | |
867 | the mode, by setting up a hook function to override the local variable | |
868 | assignments already made by the mode. But hooks are also used in other | |
869 | contexts. For example, the hook @code{suspend-hook} runs just before | |
870 | Emacs suspends itself (@pxref{Exiting}). | |
871 | ||
872 | @cindex normal hook | |
873 | Most Emacs hooks are @dfn{normal hooks}. This means that running the | |
874 | hook operates by calling all the hook functions, unconditionally, with | |
875 | no arguments. We have made an effort to keep most hooks normal so that | |
876 | you can use them in a uniform way. Every variable in Emacs whose name | |
877 | ends in @samp{-hook} is a normal hook. | |
878 | ||
879 | @cindex abnormal hook | |
880 | There are also a few @dfn{abnormal hooks}. These variables' names end | |
881 | in @samp{-hooks} or @samp{-functions}, instead of @samp{-hook}. What | |
882 | makes these hooks abnormal is that there is something peculiar about the | |
883 | way its functions are called---perhaps they are given arguments, or | |
884 | perhaps the values they return are used in some way. For example, | |
f2aa473a | 885 | @code{find-file-not-found-functions} (@pxref{Visiting}) is abnormal because |
6bf7aab6 DL |
886 | as soon as one hook function returns a non-@code{nil} value, the rest |
887 | are not called at all. The documentation of each abnormal hook variable | |
888 | explains in detail what is peculiar about it. | |
889 | ||
2038519d RS |
890 | You can set a hook variable with @code{setq} like any other Lisp |
891 | variable, but the recommended way to add a hook function to a hook | |
892 | (either normal or abnormal) is by calling @code{add-hook}. You can | |
893 | specify any valid Lisp function as the hook function, provided it can | |
894 | handle the proper number of arguments (zero arguments, in the case of | |
895 | a normal hook). Of course, not every Lisp function is @emph{useful} | |
896 | in any particular hook. | |
6bf7aab6 DL |
897 | |
898 | For example, here's how to set up a hook to turn on Auto Fill mode | |
899 | when entering Text mode and other modes based on Text mode: | |
900 | ||
901 | @example | |
902 | (add-hook 'text-mode-hook 'turn-on-auto-fill) | |
903 | @end example | |
904 | ||
905 | The next example shows how to use a hook to customize the indentation | |
906 | of C code. (People often have strong personal preferences for one | |
907 | format compared to another.) Here the hook function is an anonymous | |
908 | lambda expression. | |
909 | ||
910 | @example | |
911 | @group | |
912 | (setq my-c-style | |
913 | '((c-comment-only-line-offset . 4) | |
914 | @end group | |
915 | @group | |
916 | (c-cleanup-list . (scope-operator | |
917 | empty-defun-braces | |
918 | defun-close-semi)) | |
919 | @end group | |
920 | @group | |
921 | (c-offsets-alist . ((arglist-close . c-lineup-arglist) | |
922 | (substatement-open . 0))))) | |
923 | @end group | |
924 | ||
925 | @group | |
926 | (add-hook 'c-mode-common-hook | |
bc49c316 DL |
927 | '(lambda () |
928 | (c-add-style "my-style" my-c-style t))) | |
6bf7aab6 DL |
929 | @end group |
930 | @end example | |
931 | ||
932 | It is best to design your hook functions so that the order in which | |
933 | they are executed does not matter. Any dependence on the order is | |
934 | ``asking for trouble.'' However, the order is predictable: the most | |
935 | recently added hook functions are executed first. | |
936 | ||
2038519d RS |
937 | If you play with adding various different versions of a hook |
938 | function by calling @code{add-hook} over and over, remember that all | |
c04a2eab RS |
939 | the versions you added will remain in the hook variable together. You |
940 | can clear out individual functions with @code{remove-hook}, or do | |
941 | @code{(setq @var{hook-variable} nil)} to remove everything. | |
2038519d | 942 | |
6bf7aab6 DL |
943 | @node Locals |
944 | @subsection Local Variables | |
945 | ||
946 | @table @kbd | |
947 | @item M-x make-local-variable @key{RET} @var{var} @key{RET} | |
948 | Make variable @var{var} have a local value in the current buffer. | |
949 | @item M-x kill-local-variable @key{RET} @var{var} @key{RET} | |
950 | Make variable @var{var} use its global value in the current buffer. | |
951 | @item M-x make-variable-buffer-local @key{RET} @var{var} @key{RET} | |
952 | Mark variable @var{var} so that setting it will make it local to the | |
953 | buffer that is current at that time. | |
954 | @end table | |
955 | ||
956 | @cindex local variables | |
957 | Almost any variable can be made @dfn{local} to a specific Emacs | |
958 | buffer. This means that its value in that buffer is independent of its | |
959 | value in other buffers. A few variables are always local in every | |
960 | buffer. Every other Emacs variable has a @dfn{global} value which is in | |
961 | effect in all buffers that have not made the variable local. | |
962 | ||
963 | @findex make-local-variable | |
964 | @kbd{M-x make-local-variable} reads the name of a variable and makes it | |
965 | local to the current buffer. Further changes in this buffer will not | |
966 | affect others, and further changes in the global value will not affect this | |
967 | buffer. | |
968 | ||
969 | @findex make-variable-buffer-local | |
970 | @cindex per-buffer variables | |
971 | @kbd{M-x make-variable-buffer-local} reads the name of a variable and | |
972 | changes the future behavior of the variable so that it will become local | |
973 | automatically when it is set. More precisely, once a variable has been | |
974 | marked in this way, the usual ways of setting the variable automatically | |
975 | do @code{make-local-variable} first. We call such variables | |
976 | @dfn{per-buffer} variables. | |
977 | ||
978 | Major modes (@pxref{Major Modes}) always make variables local to the | |
979 | buffer before setting the variables. This is why changing major modes | |
980 | in one buffer has no effect on other buffers. Minor modes also work by | |
981 | setting variables---normally, each minor mode has one controlling | |
982 | variable which is non-@code{nil} when the mode is enabled (@pxref{Minor | |
983 | Modes}). For most minor modes, the controlling variable is per buffer. | |
984 | ||
985 | Emacs contains a number of variables that are always per-buffer. | |
986 | These include @code{abbrev-mode}, @code{auto-fill-function}, | |
987 | @code{case-fold-search}, @code{comment-column}, @code{ctl-arrow}, | |
988 | @code{fill-column}, @code{fill-prefix}, @code{indent-tabs-mode}, | |
989 | @code{left-margin}, @code{mode-line-format}, @code{overwrite-mode}, | |
990 | @code{selective-display-ellipses}, @code{selective-display}, | |
991 | @code{tab-width}, and @code{truncate-lines}. Some other variables are | |
992 | always local in every buffer, but they are used for internal | |
993 | purposes.@refill | |
994 | ||
995 | A few variables cannot be local to a buffer because they are always | |
996 | local to each display instead (@pxref{Multiple Displays}). If you try to | |
997 | make one of these variables buffer-local, you'll get an error message. | |
998 | ||
999 | @findex kill-local-variable | |
1000 | @kbd{M-x kill-local-variable} reads the name of a variable and makes | |
1001 | it cease to be local to the current buffer. The global value of the | |
1002 | variable henceforth is in effect in this buffer. Setting the major mode | |
1003 | kills all the local variables of the buffer except for a few variables | |
1004 | specially marked as @dfn{permanent locals}. | |
1005 | ||
1006 | @findex setq-default | |
1007 | To set the global value of a variable, regardless of whether the | |
1008 | variable has a local value in the current buffer, you can use the Lisp | |
1009 | construct @code{setq-default}. This construct is used just like | |
1010 | @code{setq}, but it sets variables' global values instead of their local | |
1011 | values (if any). When the current buffer does have a local value, the | |
1012 | new global value may not be visible until you switch to another buffer. | |
1013 | Here is an example: | |
1014 | ||
1015 | @example | |
1016 | (setq-default fill-column 75) | |
1017 | @end example | |
1018 | ||
1019 | @noindent | |
1020 | @code{setq-default} is the only way to set the global value of a variable | |
1021 | that has been marked with @code{make-variable-buffer-local}. | |
1022 | ||
1023 | @findex default-value | |
1024 | Lisp programs can use @code{default-value} to look at a variable's | |
1025 | default value. This function takes a symbol as argument and returns its | |
1026 | default value. The argument is evaluated; usually you must quote it | |
1027 | explicitly. For example, here's how to obtain the default value of | |
1028 | @code{fill-column}: | |
1029 | ||
1030 | @example | |
1031 | (default-value 'fill-column) | |
1032 | @end example | |
1033 | ||
1034 | @node File Variables | |
1035 | @subsection Local Variables in Files | |
1036 | @cindex local variables in files | |
1037 | @cindex file local variables | |
1038 | ||
1039 | A file can specify local variable values for use when you edit the | |
1040 | file with Emacs. Visiting the file checks for local variable | |
1041 | specifications; it automatically makes these variables local to the | |
1042 | buffer, and sets them to the values specified in the file. | |
1043 | ||
1044 | There are two ways to specify local variable values: in the first | |
1045 | line, or with a local variables list. Here's how to specify them in the | |
1046 | first line: | |
1047 | ||
1048 | @example | |
1049 | -*- mode: @var{modename}; @var{var}: @var{value}; @dots{} -*- | |
1050 | @end example | |
1051 | ||
1052 | @noindent | |
1053 | You can specify any number of variables/value pairs in this way, each | |
1054 | pair with a colon and semicolon as shown above. @code{mode: | |
1055 | @var{modename};} specifies the major mode; this should come first in the | |
1056 | line. The @var{value}s are not evaluated; they are used literally. | |
1057 | Here is an example that specifies Lisp mode and sets two variables with | |
1058 | numeric values: | |
1059 | ||
1060 | @smallexample | |
6a9a44bf | 1061 | ;; -*- mode: Lisp; fill-column: 75; comment-column: 50; -*- |
6bf7aab6 DL |
1062 | @end smallexample |
1063 | ||
1064 | You can also specify the coding system for a file in this way: just | |
1065 | specify a value for the ``variable'' named @code{coding}. The ``value'' | |
1066 | must be a coding system name that Emacs recognizes. @xref{Coding | |
2e66e5b7 RS |
1067 | Systems}. @w{@samp{unibyte: t}} specifies unibyte loading for a |
1068 | particular Lisp file. @xref{Enabling Multibyte}. | |
6bf7aab6 | 1069 | |
07eab3c3 EZ |
1070 | The @code{eval} pseudo-variable, described below, can be specified in |
1071 | the first line as well. | |
1072 | ||
1073 | @cindex shell scripts, and local file variables | |
1074 | In shell scripts, the first line is used to identify the script | |
d0960fb3 | 1075 | interpreter, so you cannot put any local variables there. To accommodate |
07eab3c3 EZ |
1076 | for this, when Emacs visits a shell script, it looks for local variable |
1077 | specifications in the @emph{second} line. | |
1078 | ||
6bf7aab6 DL |
1079 | A @dfn{local variables list} goes near the end of the file, in the |
1080 | last page. (It is often best to put it on a page by itself.) The local | |
1081 | variables list starts with a line containing the string @samp{Local | |
1082 | Variables:}, and ends with a line containing the string @samp{End:}. In | |
1083 | between come the variable names and values, one set per line, as | |
1084 | @samp{@var{variable}:@: @var{value}}. The @var{value}s are not | |
1085 | evaluated; they are used literally. If a file has both a local | |
1086 | variables list and a @samp{-*-} line, Emacs processes @emph{everything} | |
1087 | in the @samp{-*-} line first, and @emph{everything} in the local | |
1088 | variables list afterward. | |
1089 | ||
1090 | Here is an example of a local variables list: | |
1091 | ||
1092 | @example | |
1093 | ;;; Local Variables: *** | |
1094 | ;;; mode:lisp *** | |
1095 | ;;; comment-column:0 *** | |
1096 | ;;; comment-start: ";;; " *** | |
1097 | ;;; comment-end:"***" *** | |
1098 | ;;; End: *** | |
1099 | @end example | |
1100 | ||
1101 | As you see, each line starts with the prefix @samp{;;; } and each line | |
1102 | ends with the suffix @samp{ ***}. Emacs recognizes these as the prefix | |
1103 | and suffix based on the first line of the list, by finding them | |
1104 | surrounding the magic string @samp{Local Variables:}; then it | |
1105 | automatically discards them from the other lines of the list. | |
1106 | ||
1107 | The usual reason for using a prefix and/or suffix is to embed the | |
1108 | local variables list in a comment, so it won't confuse other programs | |
1109 | that the file is intended as input for. The example above is for a | |
1110 | language where comment lines start with @samp{;;; } and end with | |
1111 | @samp{***}; the local values for @code{comment-start} and | |
2038519d RS |
1112 | @code{comment-end} customize the rest of Emacs for this unusual |
1113 | syntax. Don't use a prefix (or a suffix) if you don't need one. | |
1114 | ||
1115 | If you write a multi-line string value, you should put the prefix | |
1116 | and suffix on each line, even lines that start or end within the | |
1117 | string. They will be stripped off for processing the list. If you | |
1118 | want to split a long string across multiple lines of the file, you can | |
1119 | use backslash-newline, which is ignored in Lisp string constants. | |
1120 | Here's an example of doing this: | |
1121 | ||
1122 | @example | |
1123 | # Local Variables: | |
1124 | # compile-command: "cc foo.c -Dfoo=bar -Dhack=whatever \ | |
1125 | # -Dmumble=blaah" | |
1126 | # End: | |
1127 | @end example | |
6bf7aab6 | 1128 | |
2e66e5b7 | 1129 | Some ``variable names'' have special meanings in a local variables |
3c338c5f RS |
1130 | list. Specifying the ``variable'' @code{mode} really sets the major |
1131 | mode, while any value specified for the ``variable'' @code{eval} is | |
1132 | simply evaluated as an expression (its value is ignored). A value for | |
1133 | @code{coding} specifies the coding system for character code | |
1134 | conversion of this file, and a value of @code{t} for @code{unibyte} | |
1135 | says to visit the file in a unibyte buffer. These four ``variables'' | |
1136 | are not really variables; setting them in any other context has no | |
1137 | special meaning. | |
1138 | ||
1139 | @emph{If @code{mode} is used to set a major mode, it should be the | |
1140 | first ``variable'' in the list.} Otherwise, the entries that precede | |
1141 | it will usually be ignored, since most modes kill all local variables | |
1142 | as part of their initialization. | |
1143 | ||
1144 | You can use the @code{mode} ``variable'' to set minor modes as well | |
1145 | as the major modes; in fact, you can use it more than once, first to | |
1146 | set the major mode and then to set minor modes which are specific to | |
1147 | particular buffers. But most minor modes should not be specified in | |
1148 | the file at all, regardless of how, because they represent user | |
1149 | preferences. | |
6bf7aab6 DL |
1150 | |
1151 | For example, you may be tempted to try to turn on Auto Fill mode with | |
1152 | a local variable list. That is a mistake. The choice of Auto Fill mode | |
1153 | or not is a matter of individual taste, not a matter of the contents of | |
1154 | particular files. If you want to use Auto Fill, set up major mode hooks | |
1155 | with your @file{.emacs} file to turn it on (when appropriate) for you | |
1156 | alone (@pxref{Init File}). Don't use a local variable list to impose | |
1157 | your taste on everyone. | |
1158 | ||
1159 | The start of the local variables list must be no more than 3000 | |
1160 | characters from the end of the file, and must be in the last page if the | |
1161 | file is divided into pages. Otherwise, Emacs will not notice it is | |
1162 | there. The purpose of this rule is so that a stray @samp{Local | |
1163 | Variables:}@: not in the last page does not confuse Emacs, and so that | |
1164 | visiting a long file that is all one page and has no local variables | |
1165 | list need not take the time to search the whole file. | |
1166 | ||
1167 | Use the command @code{normal-mode} to reset the local variables and | |
1168 | major mode of a buffer according to the file name and contents, | |
1169 | including the local variables list if any. @xref{Choosing Modes}. | |
1170 | ||
1171 | @findex enable-local-variables | |
1172 | The variable @code{enable-local-variables} controls whether to process | |
1173 | local variables in files, and thus gives you a chance to override them. | |
1174 | Its default value is @code{t}, which means do process local variables in | |
1175 | files. If you set the value to @code{nil}, Emacs simply ignores local | |
1176 | variables in files. Any other value says to query you about each file | |
1177 | that has local variables, showing you the local variable specifications | |
1178 | so you can judge. | |
1179 | ||
1180 | @findex enable-local-eval | |
1181 | The @code{eval} ``variable,'' and certain actual variables, create a | |
1182 | special risk; when you visit someone else's file, local variable | |
1183 | specifications for these could affect your Emacs in arbitrary ways. | |
89fa0de4 | 1184 | Therefore, the variable @code{enable-local-eval} controls whether Emacs |
6bf7aab6 DL |
1185 | processes @code{eval} variables, as well variables with names that end |
1186 | in @samp{-hook}, @samp{-hooks}, @samp{-function} or @samp{-functions}, | |
89fa0de4 | 1187 | and certain other variables. The three possibilities for the variable's |
6bf7aab6 DL |
1188 | value are @code{t}, @code{nil}, and anything else, just as for |
1189 | @code{enable-local-variables}. The default is @code{maybe}, which is | |
1190 | neither @code{t} nor @code{nil}, so normally Emacs does ask for | |
1191 | confirmation about file settings for these variables. | |
1192 | ||
d8f8d1bb KS |
1193 | @findex safe-local-eval-forms |
1194 | The @code{safe-local-eval-forms} is a customizable list of eval | |
1195 | forms which are safe to eval, so Emacs should not ask for | |
1196 | confirmation to evaluate these forms, even if | |
1197 | @code{enable-local-variables} says to ask for confirmation in general. | |
1198 | ||
6bf7aab6 DL |
1199 | @node Key Bindings |
1200 | @section Customizing Key Bindings | |
1201 | @cindex key bindings | |
1202 | ||
1203 | This section describes @dfn{key bindings}, which map keys to commands, | |
1204 | and @dfn{keymaps}, which record key bindings. It also explains how | |
1205 | to customize key bindings. | |
1206 | ||
1207 | Recall that a command is a Lisp function whose definition provides for | |
1208 | interactive use. Like every Lisp function, a command has a function | |
1209 | name which usually consists of lower-case letters and hyphens. | |
1210 | ||
1211 | @menu | |
1212 | * Keymaps:: Generalities. The global keymap. | |
1213 | * Prefix Keymaps:: Keymaps for prefix keys. | |
1214 | * Local Keymaps:: Major and minor modes have their own keymaps. | |
1215 | * Minibuffer Maps:: The minibuffer uses its own local keymaps. | |
1216 | * Rebinding:: How to redefine one key's meaning conveniently. | |
1217 | * Init Rebinding:: Rebinding keys with your init file, @file{.emacs}. | |
1218 | * Function Keys:: Rebinding terminal function keys. | |
1219 | * Named ASCII Chars:: Distinguishing @key{TAB} from @kbd{C-i}, and so on. | |
76dd3692 | 1220 | * Non-ASCII Rebinding:: Rebinding non-@acronym{ASCII} characters such as Latin-1. |
6bf7aab6 DL |
1221 | * Mouse Buttons:: Rebinding mouse buttons in Emacs. |
1222 | * Disabling:: Disabling a command means confirmation is required | |
1223 | before it can be executed. This is done to protect | |
1224 | beginners from surprises. | |
1225 | @end menu | |
1226 | ||
1227 | @node Keymaps | |
1228 | @subsection Keymaps | |
1229 | @cindex keymap | |
1230 | ||
1231 | The bindings between key sequences and command functions are recorded | |
1232 | in data structures called @dfn{keymaps}. Emacs has many of these, each | |
1233 | used on particular occasions. | |
1234 | ||
1235 | Recall that a @dfn{key sequence} (@dfn{key}, for short) is a sequence | |
1236 | of @dfn{input events} that have a meaning as a unit. Input events | |
1237 | include characters, function keys and mouse buttons---all the inputs | |
1238 | that you can send to the computer with your terminal. A key sequence | |
1239 | gets its meaning from its @dfn{binding}, which says what command it | |
1240 | runs. The function of keymaps is to record these bindings. | |
1241 | ||
1242 | @cindex global keymap | |
1243 | The @dfn{global} keymap is the most important keymap because it is | |
1244 | always in effect. The global keymap defines keys for Fundamental mode; | |
1245 | most of these definitions are common to most or all major modes. Each | |
1246 | major or minor mode can have its own keymap which overrides the global | |
1247 | definitions of some keys. | |
1248 | ||
1249 | For example, a self-inserting character such as @kbd{g} is | |
1250 | self-inserting because the global keymap binds it to the command | |
1251 | @code{self-insert-command}. The standard Emacs editing characters such | |
1252 | as @kbd{C-a} also get their standard meanings from the global keymap. | |
1253 | Commands to rebind keys, such as @kbd{M-x global-set-key}, actually work | |
1254 | by storing the new binding in the proper place in the global map. | |
1255 | @xref{Rebinding}. | |
1256 | ||
1257 | Meta characters work differently; Emacs translates each Meta | |
1258 | character into a pair of characters starting with @key{ESC}. When you | |
1259 | type the character @kbd{M-a} in a key sequence, Emacs replaces it with | |
1260 | @kbd{@key{ESC} a}. A meta key comes in as a single input event, but | |
1261 | becomes two events for purposes of key bindings. The reason for this is | |
1262 | historical, and we might change it someday. | |
1263 | ||
1264 | @cindex function key | |
1265 | Most modern keyboards have function keys as well as character keys. | |
1266 | Function keys send input events just as character keys do, and keymaps | |
1267 | can have bindings for them. | |
1268 | ||
af1b4255 | 1269 | On text terminals, typing a function key actually sends the computer a |
6bf7aab6 DL |
1270 | sequence of characters; the precise details of the sequence depends on |
1271 | which function key and on the model of terminal you are using. (Often | |
1272 | the sequence starts with @kbd{@key{ESC} [}.) If Emacs understands your | |
1273 | terminal type properly, it recognizes the character sequences forming | |
1274 | function keys wherever they occur in a key sequence (not just at the | |
1275 | beginning). Thus, for most purposes, you can pretend the function keys | |
1276 | reach Emacs directly and ignore their encoding as character sequences. | |
1277 | ||
1278 | @cindex mouse | |
1279 | Mouse buttons also produce input events. These events come with other | |
1280 | data---the window and position where you pressed or released the button, | |
1281 | and a time stamp. But only the choice of button matters for key | |
1282 | bindings; the other data matters only if a command looks at it. | |
1283 | (Commands designed for mouse invocation usually do look at the other | |
1284 | data.) | |
1285 | ||
1286 | A keymap records definitions for single events. Interpreting a key | |
1287 | sequence of multiple events involves a chain of keymaps. The first | |
1288 | keymap gives a definition for the first event; this definition is | |
1289 | another keymap, which is used to look up the second event in the | |
1290 | sequence, and so on. | |
1291 | ||
1292 | Key sequences can mix function keys and characters. For example, | |
1293 | @kbd{C-x @key{SELECT}} is meaningful. If you make @key{SELECT} a prefix | |
1294 | key, then @kbd{@key{SELECT} C-n} makes sense. You can even mix mouse | |
1295 | events with keyboard events, but we recommend against it, because such | |
03d48361 | 1296 | key sequences are inconvenient to use. |
6bf7aab6 | 1297 | |
03d48361 | 1298 | As a user, you can redefine any key; but it is usually best to stick |
3a2ceb9e RS |
1299 | to key sequences that consist of @kbd{C-c} followed by a letter (upper |
1300 | or lower case). These keys are ``reserved for users,'' so they won't | |
1301 | conflict with any properly designed Emacs extension. The function | |
1302 | keys @key{F5} through @key{F9} are also reserved for users. If you | |
1303 | redefine some other key, your definition may be overridden by certain | |
1304 | extensions or major modes which redefine the same key. | |
6bf7aab6 DL |
1305 | |
1306 | @node Prefix Keymaps | |
1307 | @subsection Prefix Keymaps | |
1308 | ||
1309 | A prefix key such as @kbd{C-x} or @key{ESC} has its own keymap, | |
1310 | which holds the definition for the event that immediately follows | |
1311 | that prefix. | |
1312 | ||
1313 | The definition of a prefix key is usually the keymap to use for | |
1314 | looking up the following event. The definition can also be a Lisp | |
1315 | symbol whose function definition is the following keymap; the effect is | |
1316 | the same, but it provides a command name for the prefix key that can be | |
1317 | used as a description of what the prefix key is for. Thus, the binding | |
b4fa47b5 | 1318 | of @kbd{C-x} is the symbol @code{Control-X-prefix}, whose function |
6bf7aab6 DL |
1319 | definition is the keymap for @kbd{C-x} commands. The definitions of |
1320 | @kbd{C-c}, @kbd{C-x}, @kbd{C-h} and @key{ESC} as prefix keys appear in | |
1321 | the global map, so these prefix keys are always available. | |
1322 | ||
1323 | Aside from ordinary prefix keys, there is a fictitious ``prefix key'' | |
1324 | which represents the menu bar; see @ref{Menu Bar,,,elisp, The Emacs Lisp | |
1325 | Reference Manual}, for special information about menu bar key bindings. | |
1326 | Mouse button events that invoke pop-up menus are also prefix keys; see | |
1327 | @ref{Menu Keymaps,,,elisp, The Emacs Lisp Reference Manual}, for more | |
1328 | details. | |
1329 | ||
1330 | Some prefix keymaps are stored in variables with names: | |
1331 | ||
1332 | @itemize @bullet | |
1333 | @item | |
1334 | @vindex ctl-x-map | |
1335 | @code{ctl-x-map} is the variable name for the map used for characters that | |
1336 | follow @kbd{C-x}. | |
1337 | @item | |
1338 | @vindex help-map | |
1339 | @code{help-map} is for characters that follow @kbd{C-h}. | |
1340 | @item | |
1341 | @vindex esc-map | |
1342 | @code{esc-map} is for characters that follow @key{ESC}. Thus, all Meta | |
1343 | characters are actually defined by this map. | |
1344 | @item | |
1345 | @vindex ctl-x-4-map | |
1346 | @code{ctl-x-4-map} is for characters that follow @kbd{C-x 4}. | |
1347 | @item | |
1348 | @vindex mode-specific-map | |
1349 | @code{mode-specific-map} is for characters that follow @kbd{C-c}. | |
1350 | @end itemize | |
1351 | ||
1352 | @node Local Keymaps | |
1353 | @subsection Local Keymaps | |
1354 | ||
1355 | @cindex local keymap | |
1356 | So far we have explained the ins and outs of the global map. Major | |
1357 | modes customize Emacs by providing their own key bindings in @dfn{local | |
1358 | keymaps}. For example, C mode overrides @key{TAB} to make it indent the | |
1359 | current line for C code. Portions of text in the buffer can specify | |
1360 | their own keymaps to substitute for the keymap of the buffer's major | |
1361 | mode. | |
1362 | ||
1363 | @cindex minor mode keymap | |
1364 | Minor modes can also have local keymaps. Whenever a minor mode is | |
1365 | in effect, the definitions in its keymap override both the major | |
1366 | mode's local keymap and the global keymap. | |
1367 | ||
1368 | @vindex c-mode-map | |
1369 | @vindex lisp-mode-map | |
1370 | The local keymaps for Lisp mode and several other major modes always | |
1371 | exist even when not in use. These are kept in variables named | |
1372 | @code{lisp-mode-map} and so on. For major modes less often used, the | |
1373 | local keymap is normally constructed only when the mode is used for the | |
1374 | first time in a session. This is to save space. If you wish to change | |
1375 | one of these keymaps, you must use the major mode's @dfn{mode | |
1376 | hook}---see below. | |
1377 | ||
1378 | All minor mode keymaps are created in advance. There is no way to | |
1379 | defer their creation until the first time the minor mode is enabled. | |
1380 | ||
1381 | A local keymap can locally redefine a key as a prefix key by defining | |
1382 | it as a prefix keymap. If the key is also defined globally as a prefix, | |
1383 | then its local and global definitions (both keymaps) effectively | |
1384 | combine: both of them are used to look up the event that follows the | |
1385 | prefix key. Thus, if the mode's local keymap defines @kbd{C-c} as | |
1386 | another keymap, and that keymap defines @kbd{C-z} as a command, this | |
1387 | provides a local meaning for @kbd{C-c C-z}. This does not affect other | |
1388 | sequences that start with @kbd{C-c}; if those sequences don't have their | |
1389 | own local bindings, their global bindings remain in effect. | |
1390 | ||
1391 | Another way to think of this is that Emacs handles a multi-event key | |
1392 | sequence by looking in several keymaps, one by one, for a binding of the | |
1393 | whole key sequence. First it checks the minor mode keymaps for minor | |
1394 | modes that are enabled, then it checks the major mode's keymap, and then | |
1395 | it checks the global keymap. This is not precisely how key lookup | |
1396 | works, but it's good enough for understanding ordinary circumstances. | |
1397 | ||
1398 | @cindex rebinding major mode keys | |
4ea68fcc | 1399 | @findex define-key |
6bf7aab6 DL |
1400 | To change the local bindings of a major mode, you must change the |
1401 | mode's local keymap. Normally you must wait until the first time the | |
1402 | mode is used, because most major modes don't create their keymaps until | |
1403 | then. If you want to specify something in your @file{~/.emacs} file to | |
1404 | change a major mode's bindings, you must use the mode's mode hook to | |
1405 | delay the change until the mode is first used. | |
1406 | ||
1407 | For example, the command @code{texinfo-mode} to select Texinfo mode | |
1408 | runs the hook @code{texinfo-mode-hook}. Here's how you can use the hook | |
1409 | to add local bindings (not very useful, we admit) for @kbd{C-c n} and | |
1410 | @kbd{C-c p} in Texinfo mode: | |
1411 | ||
1412 | @example | |
1413 | (add-hook 'texinfo-mode-hook | |
5d9dd378 RS |
1414 | '(lambda () |
1415 | (define-key texinfo-mode-map "\C-cp" | |
1416 | 'backward-paragraph) | |
1417 | (define-key texinfo-mode-map "\C-cn" | |
1418 | 'forward-paragraph))) | |
6bf7aab6 DL |
1419 | @end example |
1420 | ||
1421 | @xref{Hooks}. | |
1422 | ||
1423 | @node Minibuffer Maps | |
1424 | @subsection Minibuffer Keymaps | |
1425 | ||
1426 | @cindex minibuffer keymaps | |
1427 | @vindex minibuffer-local-map | |
1428 | @vindex minibuffer-local-ns-map | |
1429 | @vindex minibuffer-local-completion-map | |
1430 | @vindex minibuffer-local-must-match-map | |
78cfaa07 LT |
1431 | @vindex minibuffer-local-filename-completion-map |
1432 | @vindex minibuffer-local-must-match-filename-map | |
6bf7aab6 DL |
1433 | The minibuffer has its own set of local keymaps; they contain various |
1434 | completion and exit commands. | |
1435 | ||
1436 | @itemize @bullet | |
1437 | @item | |
1438 | @code{minibuffer-local-map} is used for ordinary input (no completion). | |
1439 | @item | |
1440 | @code{minibuffer-local-ns-map} is similar, except that @key{SPC} exits | |
1441 | just like @key{RET}. This is used mainly for Mocklisp compatibility. | |
1442 | @item | |
1443 | @code{minibuffer-local-completion-map} is for permissive completion. | |
1444 | @item | |
1445 | @code{minibuffer-local-must-match-map} is for strict completion and | |
1446 | for cautious completion. | |
78cfaa07 LT |
1447 | @item |
1448 | @code{minibuffer-local-filename-completion-map} and | |
1449 | @code{minibuffer-local-must-match-filename-map} are like the two | |
1450 | previous ones, but they are specifically for file name completion. | |
1451 | They do not bind @key{SPC}. | |
6bf7aab6 DL |
1452 | @end itemize |
1453 | ||
1454 | @node Rebinding | |
1455 | @subsection Changing Key Bindings Interactively | |
1456 | @cindex key rebinding, this session | |
4946337d | 1457 | @cindex redefining keys, this session |
6bf7aab6 DL |
1458 | |
1459 | The way to redefine an Emacs key is to change its entry in a keymap. | |
1460 | You can change the global keymap, in which case the change is effective in | |
1461 | all major modes (except those that have their own overriding local | |
1462 | definitions for the same key). Or you can change the current buffer's | |
1463 | local map, which affects all buffers using the same major mode. | |
1464 | ||
1465 | @findex global-set-key | |
1466 | @findex local-set-key | |
1467 | @findex global-unset-key | |
1468 | @findex local-unset-key | |
1469 | @table @kbd | |
1470 | @item M-x global-set-key @key{RET} @var{key} @var{cmd} @key{RET} | |
1471 | Define @var{key} globally to run @var{cmd}. | |
1472 | @item M-x local-set-key @key{RET} @var{key} @var{cmd} @key{RET} | |
1473 | Define @var{key} locally (in the major mode now in effect) to run | |
1474 | @var{cmd}. | |
1475 | @item M-x global-unset-key @key{RET} @var{key} | |
1476 | Make @var{key} undefined in the global map. | |
1477 | @item M-x local-unset-key @key{RET} @var{key} | |
1478 | Make @var{key} undefined locally (in the major mode now in effect). | |
1479 | @end table | |
1480 | ||
1481 | For example, suppose you like to execute commands in a subshell within | |
1482 | an Emacs buffer, instead of suspending Emacs and executing commands in | |
1483 | your login shell. Normally, @kbd{C-z} is bound to the function | |
1484 | @code{suspend-emacs} (when not using the X Window System), but you can | |
1485 | change @kbd{C-z} to invoke an interactive subshell within Emacs, by | |
1486 | binding it to @code{shell} as follows: | |
1487 | ||
1488 | @example | |
1489 | M-x global-set-key @key{RET} C-z shell @key{RET} | |
1490 | @end example | |
1491 | ||
1492 | @noindent | |
1493 | @code{global-set-key} reads the command name after the key. After you | |
1494 | press the key, a message like this appears so that you can confirm that | |
1495 | you are binding the key you want: | |
1496 | ||
1497 | @example | |
177c0ea7 | 1498 | Set key C-z to command: |
6bf7aab6 DL |
1499 | @end example |
1500 | ||
1501 | You can redefine function keys and mouse events in the same way; just | |
1502 | type the function key or click the mouse when it's time to specify the | |
1503 | key to rebind. | |
1504 | ||
1505 | You can rebind a key that contains more than one event in the same | |
1506 | way. Emacs keeps reading the key to rebind until it is a complete key | |
1507 | (that is, not a prefix key). Thus, if you type @kbd{C-f} for | |
1508 | @var{key}, that's the end; the minibuffer is entered immediately to | |
1509 | read @var{cmd}. But if you type @kbd{C-x}, another character is read; | |
1510 | if that is @kbd{4}, another character is read, and so on. For | |
1511 | example, | |
1512 | ||
1513 | @example | |
1514 | M-x global-set-key @key{RET} C-x 4 $ spell-other-window @key{RET} | |
1515 | @end example | |
1516 | ||
1517 | @noindent | |
1518 | redefines @kbd{C-x 4 $} to run the (fictitious) command | |
1519 | @code{spell-other-window}. | |
1520 | ||
1521 | The two-character keys consisting of @kbd{C-c} followed by a letter | |
1522 | are reserved for user customizations. Lisp programs are not supposed to | |
1523 | define these keys, so the bindings you make for them will be available | |
1524 | in all major modes and will never get in the way of anything. | |
1525 | ||
1526 | You can remove the global definition of a key with | |
1527 | @code{global-unset-key}. This makes the key @dfn{undefined}; if you | |
1528 | type it, Emacs will just beep. Similarly, @code{local-unset-key} makes | |
1529 | a key undefined in the current major mode keymap, which makes the global | |
1530 | definition (or lack of one) come back into effect in that major mode. | |
1531 | ||
1532 | If you have redefined (or undefined) a key and you subsequently wish | |
1533 | to retract the change, undefining the key will not do the job---you need | |
1534 | to redefine the key with its standard definition. To find the name of | |
1535 | the standard definition of a key, go to a Fundamental mode buffer and | |
1536 | use @kbd{C-h c}. The documentation of keys in this manual also lists | |
1537 | their command names. | |
1538 | ||
1539 | If you want to prevent yourself from invoking a command by mistake, it | |
1540 | is better to disable the command than to undefine the key. A disabled | |
1541 | command is less work to invoke when you really want to. | |
1542 | @xref{Disabling}. | |
1543 | ||
1544 | @node Init Rebinding | |
1545 | @subsection Rebinding Keys in Your Init File | |
1546 | ||
6bf7aab6 DL |
1547 | If you have a set of key bindings that you like to use all the time, |
1548 | you can specify them in your @file{.emacs} file by using their Lisp | |
4ea68fcc | 1549 | syntax. (@xref{Init File}.) |
6bf7aab6 | 1550 | |
76dd3692 EZ |
1551 | The simplest method for doing this works for @acronym{ASCII} characters and |
1552 | Meta-modified @acronym{ASCII} characters only. This method uses a string to | |
6bf7aab6 DL |
1553 | represent the key sequence you want to rebind. For example, here's how |
1554 | to bind @kbd{C-z} to @code{shell}: | |
1555 | ||
1556 | @example | |
1557 | (global-set-key "\C-z" 'shell) | |
1558 | @end example | |
1559 | ||
1560 | @noindent | |
af1b4255 RS |
1561 | This example uses a string constant containing one character, |
1562 | @kbd{C-z}. (@samp{\C-} is string syntax for a control character.) The | |
1563 | single-quote before the command name, @code{shell}, marks it as a | |
6bf7aab6 DL |
1564 | constant symbol rather than a variable. If you omit the quote, Emacs |
1565 | would try to evaluate @code{shell} immediately as a variable. This | |
1566 | probably causes an error; it certainly isn't what you want. | |
1567 | ||
af1b4255 | 1568 | Here is another example that binds the key sequence @kbd{C-x M-l}: |
6bf7aab6 DL |
1569 | |
1570 | @example | |
af1b4255 | 1571 | (global-set-key "\C-x\M-l" 'make-symbolic-link) |
03d48361 RS |
1572 | @end example |
1573 | ||
1574 | To put @key{TAB}, @key{RET}, @key{ESC}, or @key{DEL} in the | |
1575 | string, you can use the Emacs Lisp escape sequences, @samp{\t}, | |
1576 | @samp{\r}, @samp{\e}, and @samp{\d}. Here is an example which binds | |
1577 | @kbd{C-x @key{TAB}}: | |
1578 | ||
1579 | @example | |
1580 | (global-set-key "\C-x\t" 'indent-rigidly) | |
ce3bd809 RS |
1581 | @end example |
1582 | ||
76dd3692 | 1583 | These examples show how to write some other special @acronym{ASCII} characters |
ce3bd809 RS |
1584 | in strings for key bindings: |
1585 | ||
1586 | @example | |
1587 | (global-set-key "\r" 'newline) ;; @key{RET} | |
1588 | (global-set-key "\d" 'delete-backward-char) ;; @key{DEL} | |
1589 | (global-set-key "\C-x\e\e" 'repeat-complex-command) ;; @key{ESC} | |
6bf7aab6 DL |
1590 | @end example |
1591 | ||
1592 | When the key sequence includes function keys or mouse button events, | |
76dd3692 | 1593 | or non-@acronym{ASCII} characters such as @code{C-=} or @code{H-a}, you must use |
6bf7aab6 DL |
1594 | the more general method of rebinding, which uses a vector to specify the |
1595 | key sequence. | |
1596 | ||
1597 | The way to write a vector in Emacs Lisp is with square brackets around | |
1598 | the vector elements. Use spaces to separate the elements. If an | |
1599 | element is a symbol, simply write the symbol's name---no other | |
1600 | delimiters or punctuation are needed. If a vector element is a | |
1601 | character, write it as a Lisp character constant: @samp{?} followed by | |
1602 | the character as it would appear in a string. | |
1603 | ||
1604 | Here are examples of using vectors to rebind @kbd{C-=} (a control | |
76dd3692 EZ |
1605 | character not in @acronym{ASCII}), @kbd{C-M-=} (not in @acronym{ASCII} because @kbd{C-=} |
1606 | is not), @kbd{H-a} (a Hyper character; @acronym{ASCII} doesn't have Hyper at | |
17ec59da | 1607 | all), @key{F7} (a function key), and @kbd{C-Mouse-1} (a |
6bf7aab6 DL |
1608 | keyboard-modified mouse button): |
1609 | ||
1610 | @example | |
1611 | (global-set-key [?\C-=] 'make-symbolic-link) | |
17ec59da | 1612 | (global-set-key [?\M-\C-=] 'make-symbolic-link) |
6bf7aab6 DL |
1613 | (global-set-key [?\H-a] 'make-symbolic-link) |
1614 | (global-set-key [f7] 'make-symbolic-link) | |
1615 | (global-set-key [C-mouse-1] 'make-symbolic-link) | |
1616 | @end example | |
1617 | ||
ce3bd809 | 1618 | You can use a vector for the simple cases too. Here's how to |
af1b4255 | 1619 | rewrite the first six examples above to use vectors: |
6bf7aab6 DL |
1620 | |
1621 | @example | |
1622 | (global-set-key [?\C-z] 'shell) | |
6bf7aab6 | 1623 | (global-set-key [?\C-x ?l] 'make-symbolic-link) |
03d48361 | 1624 | (global-set-key [?\C-x ?\t] 'indent-rigidly) |
ce3bd809 RS |
1625 | (global-set-key [?\r] 'newline) |
1626 | (global-set-key [?\d] 'delete-backward-char) | |
1627 | (global-set-key [?\C-x ?\e ?\e] 'repeat-complex-command) | |
6bf7aab6 DL |
1628 | @end example |
1629 | ||
ce3bd809 RS |
1630 | @noindent |
1631 | As you see, you represent a multi-character key sequence with a vector | |
af1b4255 | 1632 | by listing all of the characters in order within the square brackets that |
ce3bd809 RS |
1633 | delimit the vector. |
1634 | ||
8e082ecc | 1635 | Language and coding systems can cause problems with key bindings |
76dd3692 | 1636 | for non-@acronym{ASCII} characters. @xref{Non-ASCII Rebinding}. |
94720bc7 | 1637 | |
6bf7aab6 DL |
1638 | @node Function Keys |
1639 | @subsection Rebinding Function Keys | |
1640 | ||
1641 | Key sequences can contain function keys as well as ordinary | |
1642 | characters. Just as Lisp characters (actually integers) represent | |
1643 | keyboard characters, Lisp symbols represent function keys. If the | |
1644 | function key has a word as its label, then that word is also the name of | |
1645 | the corresponding Lisp symbol. Here are the conventional Lisp names for | |
1646 | common function keys: | |
1647 | ||
1648 | @table @asis | |
1649 | @item @code{left}, @code{up}, @code{right}, @code{down} | |
1650 | Cursor arrow keys. | |
1651 | ||
1652 | @item @code{begin}, @code{end}, @code{home}, @code{next}, @code{prior} | |
1653 | Other cursor repositioning keys. | |
1654 | ||
1655 | @item @code{select}, @code{print}, @code{execute}, @code{backtab} | |
1656 | @itemx @code{insert}, @code{undo}, @code{redo}, @code{clearline} | |
6b46232e | 1657 | @itemx @code{insertline}, @code{deleteline}, @code{insertchar}, @code{deletechar} |
6bf7aab6 DL |
1658 | Miscellaneous function keys. |
1659 | ||
1660 | @item @code{f1}, @code{f2}, @dots{} @code{f35} | |
1661 | Numbered function keys (across the top of the keyboard). | |
1662 | ||
1663 | @item @code{kp-add}, @code{kp-subtract}, @code{kp-multiply}, @code{kp-divide} | |
1664 | @itemx @code{kp-backtab}, @code{kp-space}, @code{kp-tab}, @code{kp-enter} | |
1665 | @itemx @code{kp-separator}, @code{kp-decimal}, @code{kp-equal} | |
1666 | Keypad keys (to the right of the regular keyboard), with names or punctuation. | |
1667 | ||
1668 | @item @code{kp-0}, @code{kp-1}, @dots{} @code{kp-9} | |
1669 | Keypad keys with digits. | |
1670 | ||
1671 | @item @code{kp-f1}, @code{kp-f2}, @code{kp-f3}, @code{kp-f4} | |
1672 | Keypad PF keys. | |
1673 | @end table | |
1674 | ||
1675 | These names are conventional, but some systems (especially when using | |
97878c08 EZ |
1676 | X) may use different names. To make certain what symbol is used for a |
1677 | given function key on your terminal, type @kbd{C-h c} followed by that | |
1678 | key. | |
6bf7aab6 DL |
1679 | |
1680 | A key sequence which contains function key symbols (or anything but | |
af1b4255 RS |
1681 | @acronym{ASCII} characters) must be a vector rather than a string. |
1682 | Thus, to bind function key @samp{f1} to the command @code{rmail}, | |
1683 | write the following: | |
6bf7aab6 DL |
1684 | |
1685 | @example | |
1686 | (global-set-key [f1] 'rmail) | |
1687 | @end example | |
1688 | ||
1689 | @noindent | |
1690 | To bind the right-arrow key to the command @code{forward-char}, you can | |
1691 | use this expression: | |
1692 | ||
1693 | @example | |
1694 | (global-set-key [right] 'forward-char) | |
1695 | @end example | |
1696 | ||
1697 | @noindent | |
1698 | This uses the Lisp syntax for a vector containing the symbol | |
1699 | @code{right}. (This binding is present in Emacs by default.) | |
1700 | ||
1701 | @xref{Init Rebinding}, for more information about using vectors for | |
1702 | rebinding. | |
1703 | ||
1704 | You can mix function keys and characters in a key sequence. This | |
1705 | example binds @kbd{C-x @key{NEXT}} to the command @code{forward-page}. | |
1706 | ||
1707 | @example | |
1708 | (global-set-key [?\C-x next] 'forward-page) | |
1709 | @end example | |
1710 | ||
1711 | @noindent | |
1712 | where @code{?\C-x} is the Lisp character constant for the character | |
1713 | @kbd{C-x}. The vector element @code{next} is a symbol and therefore | |
1714 | does not take a question mark. | |
1715 | ||
1716 | You can use the modifier keys @key{CTRL}, @key{META}, @key{HYPER}, | |
1717 | @key{SUPER}, @key{ALT} and @key{SHIFT} with function keys. To represent | |
1718 | these modifiers, add the strings @samp{C-}, @samp{M-}, @samp{H-}, | |
1719 | @samp{s-}, @samp{A-} and @samp{S-} at the front of the symbol name. | |
1720 | Thus, here is how to make @kbd{Hyper-Meta-@key{RIGHT}} move forward a | |
1721 | word: | |
1722 | ||
1723 | @example | |
1724 | (global-set-key [H-M-right] 'forward-word) | |
1725 | @end example | |
1726 | ||
617f06a8 RS |
1727 | @cindex keypad |
1728 | Many keyboards have a ``numeric keypad'' on the right hand side. | |
1729 | The numeric keys in the keypad double up as cursor motion keys, | |
365cd965 | 1730 | toggled by a key labeled @samp{Num Lock}. By default, Emacs |
c04a2eab | 1731 | translates these keys to the corresponding keys in the main keyboard. |
365cd965 | 1732 | For example, when @samp{Num Lock} is on, the key labeled @samp{8} on |
c04a2eab RS |
1733 | the numeric keypad produces @code{kp-8}, which is translated to |
1734 | @kbd{8}; when @samp{Num Lock} is off, the same key produces | |
1735 | @code{kp-up}, which is translated to @key{UP}. If you rebind a key | |
1736 | such as @kbd{8} or @key{UP}, it affects the equivalent keypad key too. | |
1737 | However, if you rebind a @samp{kp-} key directly, that won't affect | |
1738 | its non-keypad equivalent. | |
617f06a8 RS |
1739 | |
1740 | Emacs provides a convenient method for binding the numeric keypad | |
1741 | keys, using the variables @code{keypad-setup}, | |
1742 | @code{keypad-numlock-setup}, @code{keypad-shifted-setup}, and | |
1743 | @code{keypad-numlock-shifted-setup}. These can be found in the | |
1744 | @samp{keyboard} customization group (@pxref{Easy Customization}). You | |
1745 | can rebind the keys to perform other tasks, such as issuing numeric | |
1746 | prefix arguments. | |
1747 | ||
6bf7aab6 | 1748 | @node Named ASCII Chars |
76dd3692 | 1749 | @subsection Named @acronym{ASCII} Control Characters |
6bf7aab6 DL |
1750 | |
1751 | @key{TAB}, @key{RET}, @key{BS}, @key{LFD}, @key{ESC} and @key{DEL} | |
af1b4255 RS |
1752 | started out as names for certain @acronym{ASCII} control characters, |
1753 | used so often that they have special keys of their own. For instance, | |
1754 | @key{TAB} was another name for @kbd{C-i}. Later, users found it | |
6bf7aab6 | 1755 | convenient to distinguish in Emacs between these keys and the ``same'' |
af1b4255 RS |
1756 | control characters typed with the @key{CTRL} key. Therefore, on most |
1757 | modern terminals, they are no longer the same, and @key{TAB} is | |
1758 | distinguishable from @kbd{C-i}. | |
1759 | ||
1760 | Emacs can distinguish these two kinds of input if the keyboard does. | |
1761 | It treats the ``special'' keys as function keys named @code{tab}, | |
1762 | @code{return}, @code{backspace}, @code{linefeed}, @code{escape}, and | |
1763 | @code{delete}. These function keys translate automatically into the | |
1764 | corresponding @acronym{ASCII} characters @emph{if} they have no | |
1765 | bindings of their own. As a result, neither users nor Lisp programs | |
1766 | need to pay attention to the distinction unless they care to. | |
6bf7aab6 DL |
1767 | |
1768 | If you do not want to distinguish between (for example) @key{TAB} and | |
76dd3692 | 1769 | @kbd{C-i}, make just one binding, for the @acronym{ASCII} character @key{TAB} |
6bf7aab6 | 1770 | (octal code 011). If you do want to distinguish, make one binding for |
76dd3692 | 1771 | this @acronym{ASCII} character, and another for the ``function key'' @code{tab}. |
6bf7aab6 | 1772 | |
76dd3692 | 1773 | With an ordinary @acronym{ASCII} terminal, there is no way to distinguish |
6bf7aab6 DL |
1774 | between @key{TAB} and @kbd{C-i} (and likewise for other such pairs), |
1775 | because the terminal sends the same character in both cases. | |
1776 | ||
1777 | @node Non-ASCII Rebinding | |
76dd3692 EZ |
1778 | @subsection Non-@acronym{ASCII} Characters on the Keyboard |
1779 | @cindex rebinding non-@acronym{ASCII} keys | |
1780 | @cindex non-@acronym{ASCII} keys, binding | |
6bf7aab6 | 1781 | |
6f368e2d RS |
1782 | If your keyboard has keys that send non-@acronym{ASCII} |
1783 | characters, such as accented letters, rebinding these keys | |
1784 | must be done by using a vector like this@footnote{Note that | |
1785 | you should avoid the string syntax for binding | |
1786 | non-@acronym{ASCII} characters, since they will be | |
1787 | interpreted as meta keys. @xref{Strings of Events,,,elisp, | |
1788 | The Emacs Lisp Reference Manual}.}: | |
6bf7aab6 DL |
1789 | |
1790 | @example | |
1791 | (global-set-key [?@var{char}] 'some-function) | |
1792 | @end example | |
1793 | ||
1794 | @noindent | |
6a9a44bf | 1795 | Type @kbd{C-q} followed by the key you want to bind, to insert @var{char}. |
6bf7aab6 | 1796 | |
6f368e2d | 1797 | Since this puts a non-@acronym{ASCII} character in the @file{.emacs}, |
2038519d RS |
1798 | you should specify a coding system for that file that supports the |
1799 | character in question. @xref{Init Syntax}. | |
1800 | ||
1801 | @strong{Warning:} if you change the keyboard encoding, or change | |
1802 | between multibyte and unibyte mode, or anything that would alter which | |
1803 | code @kbd{C-q} would insert for that character, you'll need to edit | |
1804 | the Lisp expression accordingly, to use the character code generated | |
1805 | by @kbd{C-q} in the new mode. | |
0a7790e0 | 1806 | |
6bf7aab6 DL |
1807 | @node Mouse Buttons |
1808 | @subsection Rebinding Mouse Buttons | |
1809 | @cindex mouse button events | |
1810 | @cindex rebinding mouse buttons | |
1811 | @cindex click events | |
1812 | @cindex drag events | |
1813 | @cindex down events | |
1814 | @cindex button down events | |
1815 | ||
1816 | Emacs uses Lisp symbols to designate mouse buttons, too. The ordinary | |
1817 | mouse events in Emacs are @dfn{click} events; these happen when you | |
1818 | press a button and release it without moving the mouse. You can also | |
1819 | get @dfn{drag} events, when you move the mouse while holding the button | |
1820 | down. Drag events happen when you finally let go of the button. | |
1821 | ||
1822 | The symbols for basic click events are @code{mouse-1} for the leftmost | |
1823 | button, @code{mouse-2} for the next, and so on. Here is how you can | |
1824 | redefine the second mouse button to split the current window: | |
1825 | ||
1826 | @example | |
1827 | (global-set-key [mouse-2] 'split-window-vertically) | |
1828 | @end example | |
1829 | ||
1830 | The symbols for drag events are similar, but have the prefix | |
1831 | @samp{drag-} before the word @samp{mouse}. For example, dragging the | |
1832 | first button generates a @code{drag-mouse-1} event. | |
1833 | ||
1834 | You can also define bindings for events that occur when a mouse button | |
1835 | is pressed down. These events start with @samp{down-} instead of | |
1836 | @samp{drag-}. Such events are generated only if they have key bindings. | |
1837 | When you get a button-down event, a corresponding click or drag event | |
1838 | will always follow. | |
1839 | ||
1840 | @cindex double clicks | |
1841 | @cindex triple clicks | |
1842 | If you wish, you can distinguish single, double, and triple clicks. A | |
1843 | double click means clicking a mouse button twice in approximately the | |
1844 | same place. The first click generates an ordinary click event. The | |
1845 | second click, if it comes soon enough, generates a double-click event | |
1846 | instead. The event type for a double-click event starts with | |
1847 | @samp{double-}: for example, @code{double-mouse-3}. | |
1848 | ||
1849 | This means that you can give a special meaning to the second click at | |
1850 | the same place, but it must act on the assumption that the ordinary | |
1851 | single click definition has run when the first click was received. | |
1852 | ||
1853 | This constrains what you can do with double clicks, but user interface | |
1854 | designers say that this constraint ought to be followed in any case. A | |
1855 | double click should do something similar to the single click, only | |
1856 | ``more so.'' The command for the double-click event should perform the | |
1857 | extra work for the double click. | |
1858 | ||
1859 | If a double-click event has no binding, it changes to the | |
1860 | corresponding single-click event. Thus, if you don't define a | |
1861 | particular double click specially, it executes the single-click command | |
1862 | twice. | |
1863 | ||
1864 | Emacs also supports triple-click events whose names start with | |
1865 | @samp{triple-}. Emacs does not distinguish quadruple clicks as event | |
1866 | types; clicks beyond the third generate additional triple-click events. | |
365cd965 LT |
1867 | However, the full number of clicks is recorded in the event list, so |
1868 | if you know Emacs Lisp you can distinguish if you really want to | |
1869 | (@pxref{Accessing Events,,, elisp, The Emacs Lisp Reference Manual}). | |
1870 | We don't recommend distinct meanings for more than three clicks, but | |
1871 | sometimes it is useful for subsequent clicks to cycle through the same | |
1872 | set of three meanings, so that four clicks are equivalent to one | |
1873 | click, five are equivalent to two, and six are equivalent to three. | |
6bf7aab6 DL |
1874 | |
1875 | Emacs also records multiple presses in drag and button-down events. | |
1876 | For example, when you press a button twice, then move the mouse while | |
1877 | holding the button, Emacs gets a @samp{double-drag-} event. And at the | |
1878 | moment when you press it down for the second time, Emacs gets a | |
1879 | @samp{double-down-} event (which is ignored, like all button-down | |
1880 | events, if it has no binding). | |
1881 | ||
1882 | @vindex double-click-time | |
17ec59da RS |
1883 | The variable @code{double-click-time} specifies how much time can |
1884 | elapse between clicks and still allow them to be grouped as a multiple | |
1885 | click. Its value is in units of milliseconds. If the value is | |
1886 | @code{nil}, double clicks are not detected at all. If the value is | |
4dfff41f | 1887 | @code{t}, then there is no time limit. The default is 500. |
6bf7aab6 | 1888 | |
4e8864c7 GM |
1889 | @vindex double-click-fuzz |
1890 | The variable @code{double-click-fuzz} specifies how much the mouse | |
365cd965 | 1891 | can move between clicks and still allow them to be grouped as a multiple |
03812848 EZ |
1892 | click. Its value is in units of pixels on windowed displays and in |
1893 | units of 1/8 of a character cell on text-mode terminals; the default is | |
1894 | 3. | |
4e8864c7 | 1895 | |
6bf7aab6 DL |
1896 | The symbols for mouse events also indicate the status of the modifier |
1897 | keys, with the usual prefixes @samp{C-}, @samp{M-}, @samp{H-}, | |
1898 | @samp{s-}, @samp{A-} and @samp{S-}. These always precede @samp{double-} | |
1899 | or @samp{triple-}, which always precede @samp{drag-} or @samp{down-}. | |
1900 | ||
1901 | A frame includes areas that don't show text from the buffer, such as | |
1902 | the mode line and the scroll bar. You can tell whether a mouse button | |
1903 | comes from a special area of the screen by means of dummy ``prefix | |
1904 | keys.'' For example, if you click the mouse in the mode line, you get | |
1905 | the prefix key @code{mode-line} before the ordinary mouse-button symbol. | |
1906 | Thus, here is how to define the command for clicking the first button in | |
1907 | a mode line to run @code{scroll-up}: | |
1908 | ||
1909 | @example | |
1910 | (global-set-key [mode-line mouse-1] 'scroll-up) | |
1911 | @end example | |
1912 | ||
1913 | Here is the complete list of these dummy prefix keys and their | |
1914 | meanings: | |
1915 | ||
1916 | @table @code | |
1917 | @item mode-line | |
1918 | The mouse was in the mode line of a window. | |
1919 | @item vertical-line | |
1920 | The mouse was in the vertical line separating side-by-side windows. (If | |
1921 | you use scroll bars, they appear in place of these vertical lines.) | |
1922 | @item vertical-scroll-bar | |
1923 | The mouse was in a vertical scroll bar. (This is the only kind of | |
1924 | scroll bar Emacs currently supports.) | |
365cd965 LT |
1925 | @item menu-bar |
1926 | The mouse was in the menu bar. | |
1927 | @item header-line | |
1928 | The mouse was in a header line. | |
6bf7aab6 DL |
1929 | @ignore |
1930 | @item horizontal-scroll-bar | |
1931 | The mouse was in a horizontal scroll bar. Horizontal scroll bars do | |
1932 | horizontal scrolling, and people don't use them often. | |
1933 | @end ignore | |
1934 | @end table | |
1935 | ||
1936 | You can put more than one mouse button in a key sequence, but it isn't | |
1937 | usual to do so. | |
1938 | ||
1939 | @node Disabling | |
1940 | @subsection Disabling Commands | |
1941 | @cindex disabled command | |
1942 | ||
1943 | Disabling a command marks the command as requiring confirmation before it | |
1944 | can be executed. The purpose of disabling a command is to prevent | |
1945 | beginning users from executing it by accident and being confused. | |
1946 | ||
1947 | An attempt to invoke a disabled command interactively in Emacs | |
1948 | displays a window containing the command's name, its documentation, and | |
1949 | some instructions on what to do immediately; then Emacs asks for input | |
1950 | saying whether to execute the command as requested, enable it and | |
1951 | execute it, or cancel. If you decide to enable the command, you are | |
1952 | asked whether to do this permanently or just for the current session. | |
6b46232e RS |
1953 | (Enabling permanently works by automatically editing your @file{.emacs} |
1954 | file.) You can also type @kbd{!} to enable @emph{all} commands, | |
1955 | for the current session only. | |
6bf7aab6 DL |
1956 | |
1957 | The direct mechanism for disabling a command is to put a | |
1958 | non-@code{nil} @code{disabled} property on the Lisp symbol for the | |
1959 | command. Here is the Lisp program to do this: | |
1960 | ||
1961 | @example | |
1962 | (put 'delete-region 'disabled t) | |
1963 | @end example | |
1964 | ||
1965 | If the value of the @code{disabled} property is a string, that string | |
1ba2ce68 | 1966 | is included in the message displayed when the command is used: |
6bf7aab6 DL |
1967 | |
1968 | @example | |
1969 | (put 'delete-region 'disabled | |
1970 | "It's better to use `kill-region' instead.\n") | |
1971 | @end example | |
1972 | ||
1973 | @findex disable-command | |
1974 | @findex enable-command | |
1975 | You can make a command disabled either by editing the @file{.emacs} | |
1976 | file directly or with the command @kbd{M-x disable-command}, which edits | |
1977 | the @file{.emacs} file for you. Likewise, @kbd{M-x enable-command} | |
1978 | edits @file{.emacs} to enable a command permanently. @xref{Init File}. | |
33b0dcb8 EZ |
1979 | |
1980 | If Emacs was invoked with the @option{-q} or @option{--no-init-file} | |
1981 | options (@pxref{Initial Options}), it will not edit your | |
1982 | @file{~/.emacs} init file. This is because editing the init file from | |
1983 | such a session might overwrite the lines you might have on your init | |
1984 | file which enable and disable commands. | |
6bf7aab6 DL |
1985 | |
1986 | Whether a command is disabled is independent of what key is used to | |
1987 | invoke it; disabling also applies if the command is invoked using | |
1988 | @kbd{M-x}. Disabling a command has no effect on calling it as a | |
1989 | function from Lisp programs. | |
1990 | ||
6bf7aab6 DL |
1991 | @node Syntax |
1992 | @section The Syntax Table | |
1993 | @cindex syntax table | |
1994 | ||
1995 | All the Emacs commands which parse words or balance parentheses are | |
1996 | controlled by the @dfn{syntax table}. The syntax table says which | |
1997 | characters are opening delimiters, which are parts of words, which are | |
dc08c4a0 RS |
1998 | string quotes, and so on. It does this by assigning each character to |
1999 | one of fifteen-odd @dfn{syntax classes}. In some cases it specifies | |
2000 | some additional information also. | |
2001 | ||
b2d77e08 RS |
2002 | Each major mode has its own syntax table (though related major modes |
2003 | sometimes share one syntax table) which it installs in each buffer | |
dc08c4a0 RS |
2004 | that uses the mode. The syntax table installed in the current buffer |
2005 | is the one that all commands use, so we call it ``the'' syntax table. | |
6bf7aab6 DL |
2006 | |
2007 | @kindex C-h s | |
2008 | @findex describe-syntax | |
dc08c4a0 RS |
2009 | To display a description of the contents of the current syntax |
2010 | table, type @kbd{C-h s} (@code{describe-syntax}). The description of | |
2011 | each character includes both the string you would have to give to | |
6bf7aab6 | 2012 | @code{modify-syntax-entry} to set up that character's current syntax, |
dc08c4a0 RS |
2013 | starting with the character which designates its syntax class, plus |
2014 | some English text to explain its meaning. | |
6bf7aab6 | 2015 | |
dc08c4a0 RS |
2016 | A syntax table is actually a Lisp object, a char-table, whose |
2017 | elements are cons cells. For full information on the syntax table, | |
2018 | see @ref{Syntax Tables,, Syntax Tables, elisp, The Emacs Lisp | |
2019 | Reference Manual}. | |
6bf7aab6 DL |
2020 | |
2021 | @node Init File | |
2022 | @section The Init File, @file{~/.emacs} | |
2023 | @cindex init file | |
2024 | @cindex Emacs initialization file | |
2025 | @cindex key rebinding, permanent | |
2026 | @cindex rebinding keys, permanently | |
2027 | @cindex startup (init file) | |
2028 | ||
af1b4255 | 2029 | When Emacs is started, it normally loads a Lisp program from the |
27a19a63 CY |
2030 | file @file{.emacs} or @file{.emacs.el} in your home directory. We |
2031 | call this file your @dfn{init file} because it specifies how to | |
2032 | initialize Emacs for you. You can use the command line switch | |
2033 | @samp{-q} to prevent loading your init file, and @samp{-u} (or | |
2034 | @samp{--user}) to specify a different user's init file (@pxref{Initial | |
2035 | Options}). | |
2036 | ||
2037 | You can also use @file{~/.emacs.d/init.el} as the init file. Emacs | |
2038 | tries this if it cannot find @file{~/.emacs} or @file{~/.emacs.el}. | |
6bf7aab6 | 2039 | |
14a893ee | 2040 | @cindex @file{default.el}, the default init file |
6bf7aab6 DL |
2041 | There can also be a @dfn{default init file}, which is the library |
2042 | named @file{default.el}, found via the standard search path for | |
2043 | libraries. The Emacs distribution contains no such library; your site | |
2044 | may create one for local customizations. If this library exists, it is | |
2045 | loaded whenever you start Emacs (except when you specify @samp{-q}). | |
2046 | But your init file, if any, is loaded first; if it sets | |
2047 | @code{inhibit-default-init} non-@code{nil}, then @file{default} is not | |
2048 | loaded. | |
2049 | ||
14a893ee EZ |
2050 | @cindex site init file |
2051 | @cindex @file{site-start.el}, the site startup file | |
6bf7aab6 | 2052 | Your site may also have a @dfn{site startup file}; this is named |
14a893ee EZ |
2053 | @file{site-start.el}, if it exists. Like @file{default.el}, Emacs |
2054 | finds this file via the standard search path for Lisp libraries. | |
2055 | Emacs loads this library before it loads your init file. To inhibit | |
25efa2de | 2056 | loading of this library, use the option @samp{--no-site-file}. |
00301578 RS |
2057 | @xref{Initial Options}. We recommend against using |
2058 | @file{site-start.el} for changes that some users may not like. It is | |
2059 | better to put them in @file{default.el}, so that users can more easily | |
2060 | override them. | |
14a893ee EZ |
2061 | |
2062 | You can place @file{default.el} and @file{site-start.el} in any of | |
2063 | the directories which Emacs searches for Lisp libraries. The variable | |
2064 | @code{load-path} (@pxref{Lisp Libraries}) specifies these directories. | |
2065 | Many sites put these files in the @file{site-lisp} subdirectory of the | |
2066 | Emacs installation directory, typically | |
2067 | @file{/usr/local/share/emacs/site-lisp}. | |
6bf7aab6 DL |
2068 | |
2069 | If you have a large amount of code in your @file{.emacs} file, you | |
2070 | should rename it to @file{~/.emacs.el}, and byte-compile it. @xref{Byte | |
2071 | Compilation,, Byte Compilation, elisp, the Emacs Lisp Reference Manual}, | |
2072 | for more information about compiling Emacs Lisp programs. | |
2073 | ||
2074 | If you are going to write actual Emacs Lisp programs that go beyond | |
2075 | minor customization, you should read the @cite{Emacs Lisp Reference Manual}. | |
2076 | @ifinfo | |
2077 | @xref{Top, Emacs Lisp, Emacs Lisp, elisp, the Emacs Lisp Reference | |
2078 | Manual}. | |
2079 | @end ifinfo | |
2080 | ||
2081 | @menu | |
2082 | * Init Syntax:: Syntax of constants in Emacs Lisp. | |
2083 | * Init Examples:: How to do some things with an init file. | |
2084 | * Terminal Init:: Each terminal type can have an init file. | |
2085 | * Find Init:: How Emacs finds the init file. | |
2086 | @end menu | |
2087 | ||
2088 | @node Init Syntax | |
2089 | @subsection Init File Syntax | |
2090 | ||
2091 | The @file{.emacs} file contains one or more Lisp function call | |
2092 | expressions. Each of these consists of a function name followed by | |
2093 | arguments, all surrounded by parentheses. For example, @code{(setq | |
2094 | fill-column 60)} calls the function @code{setq} to set the variable | |
2095 | @code{fill-column} (@pxref{Filling}) to 60. | |
2096 | ||
a67091f2 RS |
2097 | You can set any Lisp variable with @code{setq}, but with certain |
2098 | variables @code{setq} won't do what you probably want in the | |
2099 | @file{.emacs} file. Some variables automatically become buffer-local | |
2100 | when set with @code{setq}; what you want in @file{.emacs} is to set | |
2101 | the default value, using @code{setq-default}. Some customizable minor | |
2102 | mode variables do special things to enable the mode when you set them | |
2103 | with Customize, but ordinary @code{setq} won't do that; to enable the | |
2104 | mode in your @file{.emacs} file, call the minor mode command. The | |
2105 | following section has examples of both of these methods. | |
2106 | ||
2107 | The second argument to @code{setq} is an expression for the new | |
2108 | value of the variable. This can be a constant, a variable, or a | |
2109 | function call expression. In @file{.emacs}, constants are used most | |
2110 | of the time. They can be: | |
6bf7aab6 DL |
2111 | |
2112 | @table @asis | |
2113 | @item Numbers: | |
2114 | Numbers are written in decimal, with an optional initial minus sign. | |
2115 | ||
2116 | @item Strings: | |
2117 | @cindex Lisp string syntax | |
2118 | @cindex string syntax | |
2119 | Lisp string syntax is the same as C string syntax with a few extra | |
2120 | features. Use a double-quote character to begin and end a string constant. | |
2121 | ||
2122 | In a string, you can include newlines and special characters literally. | |
2123 | But often it is cleaner to use backslash sequences for them: @samp{\n} | |
2124 | for newline, @samp{\b} for backspace, @samp{\r} for carriage return, | |
2125 | @samp{\t} for tab, @samp{\f} for formfeed (control-L), @samp{\e} for | |
2126 | escape, @samp{\\} for a backslash, @samp{\"} for a double-quote, or | |
2127 | @samp{\@var{ooo}} for the character whose octal code is @var{ooo}. | |
2128 | Backslash and double-quote are the only characters for which backslash | |
2129 | sequences are mandatory. | |
2130 | ||
2131 | @samp{\C-} can be used as a prefix for a control character, as in | |
76dd3692 | 2132 | @samp{\C-s} for @acronym{ASCII} control-S, and @samp{\M-} can be used as a prefix for |
6bf7aab6 DL |
2133 | a Meta character, as in @samp{\M-a} for @kbd{Meta-A} or @samp{\M-\C-a} for |
2134 | @kbd{Control-Meta-A}.@refill | |
2135 | ||
e2bf12ba | 2136 | @cindex international characters in @file{.emacs} |
76dd3692 EZ |
2137 | @cindex non-@acronym{ASCII} characters in @file{.emacs} |
2138 | If you want to include non-@acronym{ASCII} characters in strings in your init | |
bbde4442 EZ |
2139 | file, you should consider putting a @w{@samp{-*-coding: |
2140 | @var{coding-system}-*-}} tag on the first line which states the coding | |
2ab9e3ce | 2141 | system used to save your @file{.emacs}, as explained in @ref{Recognize |
76dd3692 | 2142 | Coding}. This is because the defaults for decoding non-@acronym{ASCII} text might |
2ab9e3ce EZ |
2143 | not yet be set up by the time Emacs reads those parts of your init file |
2144 | which use such strings, possibly leading Emacs to decode those strings | |
2145 | incorrectly. | |
e2bf12ba | 2146 | |
6bf7aab6 DL |
2147 | @item Characters: |
2148 | Lisp character constant syntax consists of a @samp{?} followed by | |
2149 | either a character or an escape sequence starting with @samp{\}. | |
2150 | Examples: @code{?x}, @code{?\n}, @code{?\"}, @code{?\)}. Note that | |
2151 | strings and characters are not interchangeable in Lisp; some contexts | |
2152 | require one and some contexts require the other. | |
2153 | ||
bbde4442 | 2154 | @xref{Non-ASCII Rebinding}, for information about binding commands to |
76dd3692 | 2155 | keys which send non-@acronym{ASCII} characters. |
bbde4442 | 2156 | |
6bf7aab6 DL |
2157 | @item True: |
2158 | @code{t} stands for `true'. | |
2159 | ||
2160 | @item False: | |
2161 | @code{nil} stands for `false'. | |
2162 | ||
2163 | @item Other Lisp objects: | |
acead980 | 2164 | Write a single-quote (@code{'}) followed by the Lisp object you want. |
6bf7aab6 DL |
2165 | @end table |
2166 | ||
2167 | @node Init Examples | |
2168 | @subsection Init File Examples | |
2169 | ||
2170 | Here are some examples of doing certain commonly desired things with | |
2171 | Lisp expressions: | |
2172 | ||
2173 | @itemize @bullet | |
2174 | @item | |
2175 | Make @key{TAB} in C mode just insert a tab if point is in the middle of a | |
2176 | line. | |
2177 | ||
2178 | @example | |
2179 | (setq c-tab-always-indent nil) | |
2180 | @end example | |
2181 | ||
2182 | Here we have a variable whose value is normally @code{t} for `true' | |
2183 | and the alternative is @code{nil} for `false'. | |
2184 | ||
2185 | @item | |
2186 | Make searches case sensitive by default (in all buffers that do not | |
2187 | override this). | |
2188 | ||
2189 | @example | |
2190 | (setq-default case-fold-search nil) | |
2191 | @end example | |
2192 | ||
2193 | This sets the default value, which is effective in all buffers that do | |
2194 | not have local values for the variable. Setting @code{case-fold-search} | |
2195 | with @code{setq} affects only the current buffer's local value, which | |
2196 | is not what you probably want to do in an init file. | |
2197 | ||
2198 | @item | |
2199 | @vindex user-mail-address | |
2200 | Specify your own email address, if Emacs can't figure it out correctly. | |
2201 | ||
2202 | @example | |
2203 | (setq user-mail-address "coon@@yoyodyne.com") | |
2204 | @end example | |
2205 | ||
2206 | Various Emacs packages that need your own email address use the value of | |
2207 | @code{user-mail-address}. | |
2208 | ||
2209 | @item | |
2210 | Make Text mode the default mode for new buffers. | |
2211 | ||
2212 | @example | |
2213 | (setq default-major-mode 'text-mode) | |
2214 | @end example | |
2215 | ||
2216 | Note that @code{text-mode} is used because it is the command for | |
2217 | entering Text mode. The single-quote before it makes the symbol a | |
2218 | constant; otherwise, @code{text-mode} would be treated as a variable | |
2219 | name. | |
2220 | ||
2221 | @need 1500 | |
2222 | @item | |
2223 | Set up defaults for the Latin-1 character set | |
2224 | which supports most of the languages of Western Europe. | |
2225 | ||
2226 | @example | |
2227 | (set-language-environment "Latin-1") | |
2228 | @end example | |
2229 | ||
a67091f2 RS |
2230 | @need 1500 |
2231 | @item | |
2232 | Turn off Line Number mode, a global minor mode. | |
2233 | ||
2234 | @example | |
2235 | (line-number-mode 0) | |
2236 | @end example | |
2237 | ||
6bf7aab6 DL |
2238 | @need 1500 |
2239 | @item | |
2240 | Turn on Auto Fill mode automatically in Text mode and related modes. | |
2241 | ||
2242 | @example | |
2243 | (add-hook 'text-mode-hook | |
5d9dd378 | 2244 | '(lambda () (auto-fill-mode 1))) |
6bf7aab6 DL |
2245 | @end example |
2246 | ||
2247 | This shows how to add a hook function to a normal hook variable | |
2248 | (@pxref{Hooks}). The function we supply is a list starting with | |
2249 | @code{lambda}, with a single-quote in front of it to make it a list | |
2250 | constant rather than an expression. | |
2251 | ||
2252 | It's beyond the scope of this manual to explain Lisp functions, but for | |
2253 | this example it is enough to know that the effect is to execute | |
2254 | @code{(auto-fill-mode 1)} when Text mode is entered. You can replace | |
2255 | that with any other expression that you like, or with several | |
2256 | expressions in a row. | |
2257 | ||
2258 | Emacs comes with a function named @code{turn-on-auto-fill} whose | |
2259 | definition is @code{(lambda () (auto-fill-mode 1))}. Thus, a simpler | |
2260 | way to write the above example is as follows: | |
2261 | ||
2262 | @example | |
2263 | (add-hook 'text-mode-hook 'turn-on-auto-fill) | |
2264 | @end example | |
2265 | ||
2266 | @item | |
2267 | Load the installed Lisp library named @file{foo} (actually a file | |
2268 | @file{foo.elc} or @file{foo.el} in a standard Emacs directory). | |
2269 | ||
2270 | @example | |
2271 | (load "foo") | |
2272 | @end example | |
2273 | ||
2274 | When the argument to @code{load} is a relative file name, not starting | |
2275 | with @samp{/} or @samp{~}, @code{load} searches the directories in | |
2276 | @code{load-path} (@pxref{Lisp Libraries}). | |
2277 | ||
2278 | @item | |
2279 | Load the compiled Lisp file @file{foo.elc} from your home directory. | |
2280 | ||
2281 | @example | |
2282 | (load "~/foo.elc") | |
2283 | @end example | |
2284 | ||
2285 | Here an absolute file name is used, so no searching is done. | |
2286 | ||
bbde4442 EZ |
2287 | @item |
2288 | @cindex loading Lisp libraries automatically | |
2289 | @cindex autoload Lisp libraries | |
b2d77e08 RS |
2290 | Tell Emacs to find the definition for the function @code{myfunction} |
2291 | by loading a Lisp library named @file{mypackage} (i.e.@: a file | |
2292 | @file{mypackage.elc} or @file{mypackage.el}): | |
bbde4442 EZ |
2293 | |
2294 | @example | |
2295 | (autoload 'myfunction "mypackage" "Do what I say." t) | |
2296 | @end example | |
2297 | ||
2298 | @noindent | |
b2d77e08 RS |
2299 | Here the string @code{"Do what I say."} is the function's |
2300 | documentation string. You specify it in the @code{autoload} | |
2301 | definition so it will be available for help commands even when the | |
2302 | package is not loaded. The last argument, @code{t}, indicates that | |
2303 | this function is interactive; that is, it can be invoked interactively | |
2304 | by typing @kbd{M-x myfunction @key{RET}} or by binding it to a key. | |
2305 | If the function is not interactive, omit the @code{t} or use | |
2306 | @code{nil}. | |
bbde4442 | 2307 | |
6bf7aab6 | 2308 | @item |
af1b4255 | 2309 | Rebind the key @kbd{C-x l} to run the function @code{make-symbolic-link} |
3606516c | 2310 | (@pxref{Init Rebinding}). |
6bf7aab6 DL |
2311 | |
2312 | @example | |
2313 | (global-set-key "\C-xl" 'make-symbolic-link) | |
2314 | @end example | |
2315 | ||
2316 | or | |
2317 | ||
2318 | @example | |
2319 | (define-key global-map "\C-xl" 'make-symbolic-link) | |
2320 | @end example | |
2321 | ||
2322 | Note once again the single-quote used to refer to the symbol | |
2323 | @code{make-symbolic-link} instead of its value as a variable. | |
2324 | ||
2325 | @item | |
2326 | Do the same thing for Lisp mode only. | |
2327 | ||
2328 | @example | |
2329 | (define-key lisp-mode-map "\C-xl" 'make-symbolic-link) | |
2330 | @end example | |
2331 | ||
2332 | @item | |
2333 | Redefine all keys which now run @code{next-line} in Fundamental mode | |
2334 | so that they run @code{forward-line} instead. | |
2335 | ||
4ea68fcc | 2336 | @findex substitute-key-definition |
6bf7aab6 DL |
2337 | @example |
2338 | (substitute-key-definition 'next-line 'forward-line | |
2339 | global-map) | |
2340 | @end example | |
2341 | ||
2342 | @item | |
2343 | Make @kbd{C-x C-v} undefined. | |
2344 | ||
2345 | @example | |
2346 | (global-unset-key "\C-x\C-v") | |
2347 | @end example | |
2348 | ||
2349 | One reason to undefine a key is so that you can make it a prefix. | |
2350 | Simply defining @kbd{C-x C-v @var{anything}} will make @kbd{C-x C-v} a | |
2351 | prefix, but @kbd{C-x C-v} must first be freed of its usual non-prefix | |
2352 | definition. | |
2353 | ||
2354 | @item | |
2355 | Make @samp{$} have the syntax of punctuation in Text mode. | |
2356 | Note the use of a character constant for @samp{$}. | |
2357 | ||
2358 | @example | |
2359 | (modify-syntax-entry ?\$ "." text-mode-syntax-table) | |
2360 | @end example | |
2361 | ||
2362 | @item | |
2363 | Enable the use of the command @code{narrow-to-region} without confirmation. | |
2364 | ||
2365 | @example | |
2366 | (put 'narrow-to-region 'disabled nil) | |
2367 | @end example | |
1ac79b8b SM |
2368 | |
2369 | @item | |
2059927b | 2370 | Adjusting the configuration to various platforms and Emacs versions. |
1ac79b8b | 2371 | |
2059927b RS |
2372 | Users typically want Emacs to behave the same on all systems, so the |
2373 | same init file is right for all platforms. However, sometimes it | |
2374 | happens that a function you use for customizing Emacs is not available | |
2375 | on some platforms or in older Emacs versions. To deal with that | |
2376 | situation, put the customization inside a conditional that tests whether | |
2377 | the function or facility is available, like this: | |
1ac79b8b SM |
2378 | |
2379 | @example | |
2059927b RS |
2380 | (if (fboundp 'blink-cursor-mode) |
2381 | (blink-cursor-mode 0)) | |
1ac79b8b | 2382 | |
1ac79b8b | 2383 | (if (boundp 'coding-category-utf-8) |
2059927b | 2384 | (set-coding-priority '(coding-category-utf-8))) |
1ac79b8b SM |
2385 | @end example |
2386 | ||
2059927b RS |
2387 | @noindent |
2388 | You can also simply disregard the errors that occur if the | |
2389 | function is not defined. | |
2390 | ||
1ac79b8b | 2391 | @example |
2059927b RS |
2392 | (condition case () |
2393 | (set-face-background 'region "grey75") | |
2394 | (error nil)) | |
1ac79b8b SM |
2395 | @end example |
2396 | ||
2059927b RS |
2397 | A @code{setq} on a variable which does not exist is generally |
2398 | harmless, so those do not need a conditional. | |
6bf7aab6 DL |
2399 | @end itemize |
2400 | ||
2401 | @node Terminal Init | |
2402 | @subsection Terminal-specific Initialization | |
2403 | ||
2404 | Each terminal type can have a Lisp library to be loaded into Emacs when | |
2405 | it is run on that type of terminal. For a terminal type named | |
2406 | @var{termtype}, the library is called @file{term/@var{termtype}} and it is | |
2407 | found by searching the directories @code{load-path} as usual and trying the | |
2408 | suffixes @samp{.elc} and @samp{.el}. Normally it appears in the | |
2409 | subdirectory @file{term} of the directory where most Emacs libraries are | |
2410 | kept.@refill | |
2411 | ||
2412 | The usual purpose of the terminal-specific library is to map the | |
2413 | escape sequences used by the terminal's function keys onto more | |
2414 | meaningful names, using @code{function-key-map}. See the file | |
2415 | @file{term/lk201.el} for an example of how this is done. Many function | |
2416 | keys are mapped automatically according to the information in the | |
2417 | Termcap data base; the terminal-specific library needs to map only the | |
2418 | function keys that Termcap does not specify. | |
2419 | ||
2420 | When the terminal type contains a hyphen, only the part of the name | |
2421 | before the first hyphen is significant in choosing the library name. | |
2422 | Thus, terminal types @samp{aaa-48} and @samp{aaa-30-rv} both use | |
2423 | the library @file{term/aaa}. The code in the library can use | |
2424 | @code{(getenv "TERM")} to find the full terminal type name.@refill | |
2425 | ||
2426 | @vindex term-file-prefix | |
2427 | The library's name is constructed by concatenating the value of the | |
2428 | variable @code{term-file-prefix} and the terminal type. Your @file{.emacs} | |
2429 | file can prevent the loading of the terminal-specific library by setting | |
2430 | @code{term-file-prefix} to @code{nil}. | |
2431 | ||
2432 | @vindex term-setup-hook | |
2433 | Emacs runs the hook @code{term-setup-hook} at the end of | |
2434 | initialization, after both your @file{.emacs} file and any | |
2435 | terminal-specific library have been read in. Add hook functions to this | |
2436 | hook if you wish to override part of any of the terminal-specific | |
2437 | libraries and to define initializations for terminals that do not have a | |
2438 | library. @xref{Hooks}. | |
2439 | ||
2440 | @node Find Init | |
2441 | @subsection How Emacs Finds Your Init File | |
2442 | ||
60a96371 | 2443 | Normally Emacs uses the environment variable @env{HOME} to find |
365cd965 LT |
2444 | @file{.emacs}; that's what @samp{~} means in a file name. If |
2445 | @file{.emacs} is not found inside @file{~/} (nor @file{.emacs.el}), | |
2446 | Emacs looks for @file{~/.emacs.d/init.el} (which, like | |
2447 | @file{~/.emacs.el}, can be byte-compiled). | |
af1b4255 RS |
2448 | |
2449 | However, if you run Emacs from a shell started by @code{su}, Emacs | |
2450 | tries to find your own @file{.emacs}, not that of the user you are | |
2451 | currently pretending to be. The idea is that you should get your own | |
2452 | editor customizations even if you are running as the super user. | |
6bf7aab6 DL |
2453 | |
2454 | More precisely, Emacs first determines which user's init file to use. | |
60a96371 GM |
2455 | It gets the user name from the environment variables @env{LOGNAME} and |
2456 | @env{USER}; if neither of those exists, it uses effective user-ID. | |
2457 | If that user name matches the real user-ID, then Emacs uses @env{HOME}; | |
6bf7aab6 DL |
2458 | otherwise, it looks up the home directory corresponding to that user |
2459 | name in the system's data base of users. | |
2460 | @c LocalWords: backtab | |
ab5796a9 MB |
2461 | |
2462 | @ignore | |
2463 | arch-tag: c68abddb-4410-4fb5-925f-63394e971d93 | |
2464 | @end ignore |