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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 | |
10 | behavior of Emacs in minor ways. See @cite{The Emacs Lisp Reference | |
e538270f RS |
11 | Manual} for how to make more far-reaching changes. @xref{X Resources}, |
12 | for information on using X resources to customize Emacs. | |
6bf7aab6 | 13 | |
da6e9d86 | 14 | Customization that you do within Emacs normally affects only the |
110c9495 | 15 | particular Emacs session that you do it in---it does not persist |
da6e9d86 | 16 | between sessions unless you save the customization in a file such as |
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17 | @file{.emacs} or @file{.Xdefaults} that will affect future sessions. |
18 | @xref{Init File}. In the customization buffer, when you save | |
19 | customizations for future sessions, this actually works by editing | |
20 | @file{.emacs} for you. | |
6bf7aab6 | 21 | |
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22 | Another means of customization is the keyboard macro, which is a |
23 | sequence of keystrokes to be replayed with a single command. | |
24 | @xref{Keyboard Macros}, for full instruction how to record, manage, and | |
25 | replay sequences of keys. | |
26 | ||
6bf7aab6 DL |
27 | @menu |
28 | * Minor Modes:: Each minor mode is one feature you can turn on | |
29 | independently of any others. | |
78b83812 | 30 | * Easy Customization:: Convenient way to browse and change user options. |
6bf7aab6 DL |
31 | * Variables:: Many Emacs commands examine Emacs variables |
32 | to decide what to do; by setting variables, | |
33 | you can control their functioning. | |
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34 | * Key Bindings:: The keymaps say what command each key runs. |
35 | By changing them, you can "redefine keys". | |
6bf7aab6 | 36 | * Syntax:: The syntax table controls how words and |
78b83812 | 37 | expressions are parsed. |
6bf7aab6 | 38 | * Init File:: How to write common customizations in the |
177c0ea7 | 39 | @file{.emacs} file. |
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40 | @end menu |
41 | ||
42 | @node Minor Modes | |
43 | @section Minor Modes | |
44 | @cindex minor modes | |
45 | @cindex mode, minor | |
46 | ||
47 | Minor modes are optional features which you can turn on or off. For | |
48 | example, Auto Fill mode is a minor mode in which @key{SPC} breaks lines | |
49 | between words as you type. All the minor modes are independent of each | |
50 | other and of the selected major mode. Most minor modes say in the mode | |
51 | line when they are on; for example, @samp{Fill} in the mode line means | |
52 | that Auto Fill mode is on. | |
53 | ||
54 | Append @code{-mode} to the name of a minor mode to get the name of a | |
55 | command function that turns the mode on or off. Thus, the command to | |
56 | enable or disable Auto Fill mode is called @kbd{M-x auto-fill-mode}. These | |
57 | commands are usually invoked with @kbd{M-x}, but you can bind keys to them | |
58 | if you wish. With no argument, the function turns the mode on if it was | |
59 | off and off if it was on. This is known as @dfn{toggling}. A positive | |
60 | argument always turns the mode on, and an explicit zero argument or a | |
61 | negative argument always turns it off. | |
62 | ||
da6e9d86 RS |
63 | Some minor modes are global: while enabled, they affect everything |
64 | you do in the Emacs session, in all buffers. Other minor modes are | |
65 | buffer-local; they apply only to the current buffer, so you can enable | |
66 | the mode in certain buffers and not others. | |
67 | ||
68 | For most minor modes, the command name is also the name of a | |
69 | variable which directly controls the mode. The mode is enabled | |
70 | whenever this variable's value is non-@code{nil}, and the minor-mode | |
71 | command works by setting the variable. For example, the command | |
72 | @code{outline-minor-mode} works by setting the value of | |
73 | @code{outline-minor-mode} as a variable; it is this variable that | |
74 | directly turns Outline minor mode on and off. To check whether a | |
75 | given minor mode works this way, use @kbd{C-h v} to ask for | |
76 | documentation on the variable name. | |
77 | ||
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78 | These minor-mode variables provide a good way for Lisp programs to |
79 | turn minor modes on and off; they are also useful in a file's local | |
80 | variables list (@pxref{File Variables}). But please think twice | |
81 | before setting minor modes with a local variables list, because most | |
82 | minor modes are a matter of user preference---other users editing the | |
83 | same file might not want the same minor modes you prefer. | |
da6e9d86 | 84 | |
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85 | The most useful buffer-local minor modes include Abbrev mode, Auto |
86 | Fill mode, Auto Save mode, Font-Lock mode, Glasses mode, ISO Accents | |
87 | mode, Outline minor mode, Overwrite mode, and Binary Overwrite mode. | |
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88 | |
89 | Abbrev mode allows you to define abbreviations that automatically expand | |
90 | as you type them. For example, @samp{amd} might expand to @samp{abbrev | |
91 | mode}. @xref{Abbrevs}, for full information. | |
92 | ||
93 | Auto Fill mode allows you to enter filled text without breaking lines | |
94 | explicitly. Emacs inserts newlines as necessary to prevent lines from | |
95 | becoming too long. @xref{Filling}. | |
96 | ||
97 | Auto Save mode causes the contents of a buffer to be saved | |
98 | periodically to reduce the amount of work you can lose in case of a | |
99 | system crash. @xref{Auto Save}. | |
100 | ||
101 | Enriched mode enables editing and saving of formatted text. | |
102 | @xref{Formatted Text}. | |
103 | ||
104 | Flyspell mode automatically highlights misspelled words. | |
105 | @xref{Spelling}. | |
106 | ||
107 | Font-Lock mode automatically highlights certain textual units found in | |
108 | programs, such as comments, strings, and function names being defined. | |
109 | This requires a window system that can display multiple fonts. | |
110 | @xref{Faces}. | |
111 | ||
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112 | ISO Accents mode makes the characters @samp{`}, @samp{'}, @samp{"}, |
113 | @samp{^}, @samp{/} and @samp{~} combine with the following letter, to | |
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114 | produce an accented letter in the ISO Latin-1 character set. The |
115 | newer and more general feature of input methods more or less | |
116 | supersedes ISO Accents mode. @xref{Single-Byte Character Support}. | |
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117 | |
118 | Outline minor mode provides the same facilities as the major mode | |
119 | called Outline mode; but since it is a minor mode instead, you can | |
120 | combine it with any major mode. @xref{Outline Mode}. | |
121 | ||
122 | @cindex Overwrite mode | |
123 | @cindex mode, Overwrite | |
6bf7aab6 DL |
124 | Overwrite mode causes ordinary printing characters to replace existing |
125 | text instead of shoving it to the right. For example, if point is in | |
126 | front of the @samp{B} in @samp{FOOBAR}, then in Overwrite mode typing a | |
127 | @kbd{G} changes it to @samp{FOOGAR}, instead of producing @samp{FOOGBAR} | |
128 | as usual. In Overwrite mode, the command @kbd{C-q} inserts the next | |
129 | character whatever it may be, even if it is a digit---this gives you a | |
130 | way to insert a character instead of replacing an existing character. | |
131 | ||
f932771a EZ |
132 | @findex overwrite-mode |
133 | @kindex INSERT | |
134 | The command @code{overwrite-mode} is an exception to the rule that | |
135 | commands which toggle minor modes are normally not bound to keys: it is | |
136 | bound to the @key{INSERT} function key. This is because many other | |
137 | programs bind @key{INSERT} to similar functions. | |
138 | ||
139 | @findex binary-overwrite-mode | |
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140 | Binary Overwrite mode is a variant of Overwrite mode for editing |
141 | binary files; it treats newlines and tabs like other characters, so that | |
142 | they overwrite other characters and can be overwritten by them. | |
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143 | In Binary Overwrite mode, digits after @kbd{C-q} specify an |
144 | octal character code, as usual. | |
6bf7aab6 | 145 | |
c04a2eab RS |
146 | Here are some useful minor modes that normally apply to all buffers |
147 | at once. Since each is enabled or disabled by the value of a | |
148 | variable, you @emph{can} set them differently for particular buffers, | |
149 | by explicitly making the corresponding variables local in those | |
150 | buffers. @xref{Locals}. | |
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151 | |
152 | Icomplete mode displays an indication of available completions when | |
153 | you are in the minibuffer and completion is active. @xref{Completion | |
154 | Options}. | |
155 | ||
156 | Line Number mode enables continuous display in the mode line of the | |
5d9dd378 | 157 | line number of point, and Column Number mode enables display of the |
6ca0edfe | 158 | column number. @xref{Mode Line}. |
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159 | |
160 | Scroll Bar mode gives each window a scroll bar (@pxref{Scroll Bars}). | |
161 | Menu Bar mode gives each frame a menu bar (@pxref{Menu Bars}). Both of | |
162 | these modes are enabled by default when you use the X Window System. | |
163 | ||
164 | In Transient Mark mode, every change in the buffer contents | |
165 | ``deactivates'' the mark, so that commands that operate on the region | |
166 | will get an error. This means you must either set the mark, or | |
167 | explicitly ``reactivate'' it, before each command that uses the region. | |
168 | The advantage of Transient Mark mode is that Emacs can display the | |
6ca0edfe | 169 | region highlighted (currently only when using X). @xref{Mark}. |
6bf7aab6 | 170 | |
6bf7aab6 | 171 | @node Easy Customization |
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172 | @section Easy Customization Interface |
173 | ||
174 | @cindex user option | |
175 | Emacs has many @dfn{user options} which have values that you can set | |
89fa0de4 RS |
176 | in order to customize various commands. Many user options are |
177 | documented in this manual. Most user options are actually Lisp | |
178 | variables (@pxref{Variables}), so their names appear in the Variable | |
179 | Index (@pxref{Variable Index}). The rest are faces and their | |
180 | attributes (@pxref{Faces}). | |
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181 | |
182 | @findex customize | |
183 | @cindex customization buffer | |
2cf726a1 | 184 | You can browse interactively through the user options and change |
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185 | some of them using @kbd{M-x customize}. This command creates a |
186 | @dfn{customization buffer}, which offers commands to navigate through | |
187 | a logically organized structure of the Emacs user options; you can | |
188 | also use it to edit and set their values, and to save settings | |
189 | permanently in your @file{~/.emacs} file (@pxref{Init File}). | |
190 | ||
191 | The appearance of the example buffers in this section is typically | |
192 | different under a window system, since faces are then used to indicate | |
193 | the active fields and other features. | |
c9f2d80c | 194 | |
6bf7aab6 | 195 | @menu |
af1b4255 | 196 | * Groups: Customization Groups. How options are classified in a structure. |
70b96d19 | 197 | * Changing a Variable:: How to edit a value and set an option. |
88ca5bbf | 198 | * Saving Customizations:: Details of saving customizations. |
6bf7aab6 DL |
199 | * Face Customization:: How to edit the attributes of a face. |
200 | * Specific Customization:: Making a customization buffer for specific | |
89fa0de4 | 201 | variables, faces, or groups. |
4242b8d6 CY |
202 | * Custom Themes:: How to define collections of customized options |
203 | that can be loaded and unloaded together. | |
6bf7aab6 DL |
204 | @end menu |
205 | ||
206 | @node Customization Groups | |
bba2a48e | 207 | @subsection Customization Groups |
6bf7aab6 DL |
208 | @cindex customization groups |
209 | ||
210 | For customization purposes, user options are organized into | |
211 | @dfn{groups} to help you find them. Groups are collected into bigger | |
212 | groups, all the way up to a master group called @code{Emacs}. | |
213 | ||
214 | @kbd{M-x customize} creates a customization buffer that shows the | |
215 | top-level @code{Emacs} group and the second-level groups immediately | |
216 | under it. It looks like this, in part: | |
217 | ||
218 | @smallexample | |
219 | /- Emacs group: ---------------------------------------------------\ | |
220 | [State]: visible group members are all at standard settings. | |
221 | Customization of the One True Editor. | |
222 | See also [Manual]. | |
223 | ||
177c0ea7 | 224 | Editing group: [Go to Group] |
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225 | Basic text editing facilities. |
226 | ||
177c0ea7 | 227 | External group: [Go to Group] |
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228 | Interfacing to external utilities. |
229 | ||
230 | @var{more second-level groups} | |
231 | ||
232 | \- Emacs group end ------------------------------------------------/ | |
233 | ||
234 | @end smallexample | |
235 | ||
236 | @noindent | |
237 | This says that the buffer displays the contents of the @code{Emacs} | |
238 | group. The other groups are listed because they are its contents. But | |
239 | they are listed differently, without indentation and dashes, because | |
240 | @emph{their} contents are not included. Each group has a single-line | |
241 | documentation string; the @code{Emacs} group also has a @samp{[State]} | |
242 | line. | |
243 | ||
244 | @cindex editable fields (customization buffer) | |
245 | @cindex active fields (customization buffer) | |
246 | Most of the text in the customization buffer is read-only, but it | |
247 | typically includes some @dfn{editable fields} that you can edit. There | |
248 | are also @dfn{active fields}; this means a field that does something | |
249 | when you @dfn{invoke} it. To invoke an active field, either click on it | |
250 | with @kbd{Mouse-1}, or move point to it and type @key{RET}. | |
251 | ||
252 | For example, the phrase @samp{[Go to Group]} that appears in a | |
253 | second-level group is an active field. Invoking the @samp{[Go to | |
254 | Group]} field for a group creates a new customization buffer, which | |
255 | shows that group and its contents. This field is a kind of hypertext | |
256 | link to another group. | |
257 | ||
17ec59da RS |
258 | The @code{Emacs} group includes a few user options itself, but |
259 | mainly it contains other groups, which contain more groups, which | |
260 | contain the user options. By browsing the hierarchy of groups, you | |
261 | will eventually find the feature you are interested in customizing. | |
89fa0de4 | 262 | Then you can use the customization buffer to set the options |
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263 | pertaining to that feature. You can also go straight to a particular |
264 | group by name, using the command @kbd{M-x customize-group}. | |
6bf7aab6 DL |
265 | |
266 | @findex customize-browse | |
267 | You can view the structure of customization groups on a larger scale | |
268 | with @kbd{M-x customize-browse}. This command creates a special kind of | |
269 | customization buffer which shows only the names of the groups (and | |
89fa0de4 | 270 | variables and faces), and their structure. |
6bf7aab6 DL |
271 | |
272 | In this buffer, you can show the contents of a group by invoking | |
273 | @samp{[+]}. When the group contents are visible, this button changes to | |
274 | @samp{[-]}; invoking that hides the group contents. | |
275 | ||
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276 | Each group, variable, or face name in this buffer has an active field |
277 | which says @samp{[Group]}, @samp{[Variable]} or @samp{[Face]}. Invoking | |
6bf7aab6 | 278 | that active field creates an ordinary customization buffer showing just |
89fa0de4 | 279 | that group and its contents, just that variable, or just that face. |
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280 | This is the way to set values in it. |
281 | ||
89fa0de4 RS |
282 | @node Changing a Variable |
283 | @subsection Changing a Variable | |
6bf7aab6 | 284 | |
89fa0de4 | 285 | Here is an example of what a variable looks like in the |
6bf7aab6 DL |
286 | customization buffer: |
287 | ||
288 | @smallexample | |
6b46232e | 289 | Kill Ring Max: [Hide] 60 |
89fa0de4 | 290 | [State]: this variable is unchanged from its standard setting. |
6bf7aab6 DL |
291 | Maximum length of kill ring before oldest elements are thrown away. |
292 | @end smallexample | |
293 | ||
6b46232e | 294 | The text following @samp{[Hide]}, @samp{60} in this case, indicates |
89fa0de4 | 295 | the current value of the variable. If you see @samp{[Show]} instead of |
6bf7aab6 DL |
296 | @samp{[Hide]}, it means that the value is hidden; the customization |
297 | buffer initially hides values that take up several lines. Invoke | |
298 | @samp{[Show]} to show the value. | |
299 | ||
300 | The line after the option name indicates the @dfn{customization state} | |
89fa0de4 | 301 | of the variable: in the example above, it says you have not changed the |
6bf7aab6 DL |
302 | option yet. The word @samp{[State]} at the beginning of this line is |
303 | active; you can get a menu of various operations by invoking it with | |
304 | @kbd{Mouse-1} or @key{RET}. These operations are essential for | |
89fa0de4 | 305 | customizing the variable. |
6bf7aab6 DL |
306 | |
307 | The line after the @samp{[State]} line displays the beginning of the | |
89fa0de4 | 308 | variable's documentation string. If there are more lines of |
6bf7aab6 DL |
309 | documentation, this line ends with @samp{[More]}; invoke this to show |
310 | the full documentation string. | |
311 | ||
312 | To enter a new value for @samp{Kill Ring Max}, move point to the value | |
313 | and edit it textually. For example, you can type @kbd{M-d}, then insert | |
314 | another number. | |
315 | ||
316 | When you begin to alter the text, you will see the @samp{[State]} line | |
317 | change to say that you have edited the value: | |
318 | ||
319 | @smallexample | |
89fa0de4 | 320 | [State]: you have edited the value as text, but not set the variable. |
6bf7aab6 DL |
321 | @end smallexample |
322 | ||
323 | @cindex setting option value | |
89fa0de4 RS |
324 | Editing the value does not actually set the variable. To do |
325 | that, you must @dfn{set} it. To do this, invoke the word | |
6bf7aab6 DL |
326 | @samp{[State]} and choose @samp{Set for Current Session}. |
327 | ||
89fa0de4 | 328 | The state of the variable changes visibly when you set it: |
6bf7aab6 DL |
329 | |
330 | @smallexample | |
89fa0de4 | 331 | [State]: you have set this variable, but not saved it for future sessions. |
6bf7aab6 DL |
332 | @end smallexample |
333 | ||
334 | You don't have to worry about specifying a value that is not valid; | |
89fa0de4 | 335 | setting the variable checks for validity and will not really install an |
6bf7aab6 DL |
336 | unacceptable value. |
337 | ||
338 | @kindex M-TAB @r{(customization buffer)} | |
339 | @findex widget-complete | |
340 | While editing a value or field that is a file name, directory name, | |
ad5e19b3 RS |
341 | command name, or anything else for which completion is defined, you |
342 | can type @kbd{M-@key{TAB}} (@code{widget-complete}) to do completion. | |
343 | (@kbd{@key{ESC} @key{TAB}} and @kbd{C-M-i} do the same thing.) | |
6bf7aab6 | 344 | |
89fa0de4 RS |
345 | Some variables have a small fixed set of possible legitimate values. |
346 | These variables don't let you edit the value textually. Instead, an | |
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347 | active field @samp{[Value Menu]} appears before the value; invoke this |
348 | field to edit the value. For a boolean ``on or off'' value, the active | |
349 | field says @samp{[Toggle]}, and it changes to the other value. | |
350 | @samp{[Value Menu]} and @samp{[Toggle]} edit the buffer; the changes | |
351 | take effect when you use the @samp{Set for Current Session} operation. | |
352 | ||
89fa0de4 | 353 | Some variables have values with complex structure. For example, the |
c9f2d80c DL |
354 | value of @code{file-coding-system-alist} is an association list. Here |
355 | is how it appears in the customization buffer: | |
6bf7aab6 DL |
356 | |
357 | @smallexample | |
c9f2d80c DL |
358 | File Coding System Alist: [Hide] |
359 | [INS] [DEL] File regexp: \.elc\' | |
360 | Choice: [Value Menu] Encoding/decoding pair: | |
361 | Decoding: emacs-mule | |
362 | Encoding: emacs-mule | |
363 | [INS] [DEL] File regexp: \(\`\|/\)loaddefs.el\' | |
364 | Choice: [Value Menu] Encoding/decoding pair: | |
6b46232e RS |
365 | Decoding: raw-text |
366 | Encoding: raw-text-unix | |
c9f2d80c DL |
367 | [INS] [DEL] File regexp: \.tar\' |
368 | Choice: [Value Menu] Encoding/decoding pair: | |
369 | Decoding: no-conversion | |
370 | Encoding: no-conversion | |
371 | [INS] [DEL] File regexp: | |
372 | Choice: [Value Menu] Encoding/decoding pair: | |
373 | Decoding: undecided | |
374 | Encoding: nil | |
5d9dd378 | 375 | [INS] |
89fa0de4 | 376 | [State]: this variable is unchanged from its standard setting. |
c9f2d80c | 377 | Alist to decide a coding system to use for a file I/O operation. [Hide] |
5d9dd378 RS |
378 | The format is ((PATTERN . VAL) ...), |
379 | where PATTERN is a regular expression matching a file name, | |
380 | @r{[@dots{}more lines of documentation@dots{}]} | |
6bf7aab6 DL |
381 | @end smallexample |
382 | ||
383 | @noindent | |
5d9dd378 RS |
384 | Each association in the list appears on four lines, with several |
385 | editable or ``active'' fields. You can edit the regexps and coding | |
386 | systems using ordinary editing commands. You can also invoke | |
387 | @samp{[Value Menu]} to switch to a kind of value---for instance, to | |
388 | specify a function instead of a pair of coding systems. | |
389 | ||
390 | To delete an association from the list, invoke the @samp{[DEL]} button | |
391 | for that item. To add an association, invoke @samp{[INS]} at the | |
392 | position where you want to add it. There is an @samp{[INS]} button | |
393 | between each pair of association, another at the beginning and another | |
394 | at the end, so you can add the new association at any position in the | |
395 | list. | |
6bf7aab6 DL |
396 | |
397 | @kindex TAB @r{(customization buffer)} | |
398 | @kindex S-TAB @r{(customization buffer)} | |
399 | @findex widget-forward | |
400 | @findex widget-backward | |
401 | Two special commands, @key{TAB} and @kbd{S-@key{TAB}}, are useful for | |
402 | moving through the customization buffer. @key{TAB} | |
403 | (@code{widget-forward}) moves forward to the next active or editable | |
404 | field; @kbd{S-@key{TAB}} (@code{widget-backward}) moves backward to the | |
405 | previous active or editable field. | |
406 | ||
407 | Typing @key{RET} on an editable field also moves forward, just like | |
5d9dd378 RS |
408 | @key{TAB}. We set it up this way because people often type @key{RET} |
409 | when they are finished editing a field. To insert a newline within an | |
410 | editable field, use @kbd{C-o} or @kbd{C-q C-j}. | |
6bf7aab6 | 411 | |
89fa0de4 RS |
412 | @cindex saving variable value |
413 | @cindex customized variables, saving | |
414 | Setting the variable changes its value in the current Emacs session; | |
88ca5bbf | 415 | @dfn{saving} the value changes it for future sessions as well. To |
89fa0de4 | 416 | save the variable, invoke @samp{[State]} and select the @samp{Save for |
88ca5bbf | 417 | Future Sessions} operation. This works by writing code so as to set |
89fa0de4 | 418 | the variable again, each time you start Emacs (@pxref{Saving |
88ca5bbf | 419 | Customizations}). |
f4220fcd | 420 | |
89fa0de4 | 421 | You can also restore the variable to its standard value by invoking |
88ca5bbf RS |
422 | @samp{[State]} and selecting the @samp{Erase Customization} operation. |
423 | There are actually three reset operations: | |
6bf7aab6 DL |
424 | |
425 | @table @samp | |
426 | @item Reset | |
89fa0de4 | 427 | If you have made some modifications and not yet set the variable, |
6bf7aab6 DL |
428 | this restores the text in the customization buffer to match |
429 | the actual value. | |
430 | ||
431 | @item Reset to Saved | |
89fa0de4 | 432 | This restores the value of the variable to the last saved value, |
6bf7aab6 DL |
433 | and updates the text accordingly. |
434 | ||
0a7790e0 | 435 | @item Erase Customization |
89fa0de4 | 436 | This sets the variable to its standard value, and updates the text |
6bf7aab6 DL |
437 | accordingly. This also eliminates any saved value for the option, |
438 | so that you will get the standard value in future Emacs sessions. | |
88ca5bbf RS |
439 | |
440 | @item Use Backup Value | |
89fa0de4 RS |
441 | This sets the variable to a previous value that was set in the |
442 | customization buffer in this session. If you customize a variable | |
bba2a48e | 443 | and then reset it, which discards the customized value, |
88ca5bbf | 444 | you can get the customized value back again with this operation. |
6bf7aab6 DL |
445 | @end table |
446 | ||
0a7790e0 | 447 | @cindex comments on customized options |
5d9dd378 RS |
448 | Sometimes it is useful to record a comment about a specific |
449 | customization. Use the @samp{Add Comment} item from the | |
450 | @samp{[State]} menu to create a field for entering the comment. The | |
451 | comment you enter will be saved, and displayed again if you again view | |
89fa0de4 | 452 | the same variable in a customization buffer, even in another session. |
0a7790e0 | 453 | |
6bf7aab6 DL |
454 | The state of a group indicates whether anything in that group has been |
455 | edited, set or saved. You can select @samp{Set for Current Session}, | |
456 | @samp{Save for Future Sessions} and the various kinds of @samp{Reset} | |
457 | operation for the group; these operations on the group apply to all | |
458 | options in the group and its subgroups. | |
459 | ||
460 | Near the top of the customization buffer there are two lines | |
461 | containing several active fields: | |
462 | ||
463 | @smallexample | |
464 | [Set for Current Session] [Save for Future Sessions] | |
0a7790e0 | 465 | [Reset] [Reset to Saved] [Erase Customization] [Finish] |
6bf7aab6 DL |
466 | @end smallexample |
467 | ||
bc49c316 | 468 | @vindex custom-buffer-done-function |
6bf7aab6 | 469 | @noindent |
0a7790e0 | 470 | Invoking @samp{[Finish]} either buries or kills this customization |
bc49c316 DL |
471 | buffer according to the setting of the option |
472 | @code{custom-buffer-done-function}; the default is to bury the buffer. | |
473 | Each of the other fields performs an operation---set, save or | |
89fa0de4 RS |
474 | reset---on each of the options in the buffer that could meaningfully |
475 | be set, saved or reset. They do not operate on options whose values | |
476 | are hidden. | |
6bf7aab6 | 477 | |
88ca5bbf | 478 | @node Saving Customizations |
bba2a48e | 479 | @subsection Saving Customizations |
88ca5bbf RS |
480 | |
481 | @vindex custom-file | |
482 | The customization buffer normally saves customizations in | |
483 | @file{~/.emacs}. If you wish, you can save customizations in another | |
484 | file instead. To make this work, your @file{~/.emacs} should set | |
d3675605 RS |
485 | @code{custom-file} to the name of that file. Then you should load the |
486 | file by calling @code{load}. For example: | |
88ca5bbf RS |
487 | |
488 | @example | |
ed930870 LT |
489 | (setq custom-file "~/.emacs-custom.el") |
490 | (load custom-file) | |
88ca5bbf RS |
491 | @end example |
492 | ||
22667510 LT |
493 | You can also use @code{custom-file} to specify different |
494 | customization files for different Emacs versions, like this: | |
88ca5bbf RS |
495 | |
496 | @example | |
22667510 LT |
497 | (cond ((< emacs-major-version 21) |
498 | ;; @r{Emacs 20 customization.} | |
499 | (setq custom-file "~/.custom-20.el")) | |
500 | ((and (= emacs-major-version 21) (< emacs-minor-version 4)) | |
501 | ;; @r{Emacs 21 customization, before version 21.4.} | |
502 | (setq custom-file "~/.custom-21.el")) | |
bf247b6e | 503 | ((< emacs-major-version 22) |
22667510 | 504 | ;; @r{Emacs version 21.4 or later.} |
bf247b6e KS |
505 | (setq custom-file "~/.custom-21.4.el")) |
506 | (t | |
507 | ;; @r{Emacs version 22.1 or later.} | |
508 | (setq custom-file "~/.custom-22.el"))) | |
22667510 LT |
509 | |
510 | (load custom-file) | |
88ca5bbf RS |
511 | @end example |
512 | ||
513 | If Emacs was invoked with the @option{-q} or @option{--no-init-file} | |
514 | options (@pxref{Initial Options}), it will not let you save your | |
515 | customizations in your @file{~/.emacs} init file. This is because | |
516 | saving customizations from such a session would wipe out all the other | |
517 | customizations you might have on your init file. | |
518 | ||
6bf7aab6 | 519 | @node Face Customization |
bba2a48e | 520 | @subsection Customizing Faces |
6bf7aab6 DL |
521 | @cindex customizing faces |
522 | @cindex bold font | |
523 | @cindex italic font | |
524 | @cindex fonts and faces | |
525 | ||
89fa0de4 RS |
526 | In addition to variables, some customization groups also include |
527 | faces. When you show the contents of a group, both the variables and | |
6bf7aab6 DL |
528 | the faces in the group appear in the customization buffer. Here is an |
529 | example of how a face looks: | |
530 | ||
531 | @smallexample | |
6bdcb1dc | 532 | Custom Changed Face:(sample) [Hide] |
6bf7aab6 | 533 | [State]: this face is unchanged from its standard setting. |
6bdcb1dc MB |
534 | Face used when the customize item has been changed. |
535 | Parent groups: => Custom Magic Faces | |
536 | Attributes: [ ] Font Family: * | |
537 | [ ] Width: * | |
538 | [ ] Height: * | |
539 | [ ] Weight: * | |
540 | [ ] Slant: * | |
541 | [ ] Underline: * | |
542 | [ ] Overline: * | |
543 | [ ] Strike-through: * | |
544 | [ ] Box around text: * | |
545 | [ ] Inverse-video: * | |
546 | [X] Foreground: white (sample) | |
547 | [X] Background: blue (sample) | |
548 | [ ] Stipple: * | |
549 | [ ] Inherit: * | |
6bf7aab6 DL |
550 | @end smallexample |
551 | ||
552 | Each face attribute has its own line. The @samp{[@var{x}]} field | |
553 | before the attribute name indicates whether the attribute is | |
554 | @dfn{enabled}; @samp{X} means that it is. You can enable or disable the | |
555 | attribute by invoking that field. When the attribute is enabled, you | |
556 | can change the attribute value in the usual ways. | |
557 | ||
ee264870 RS |
558 | For the colors, you can specify a color name (use @kbd{M-x |
559 | list-colors-display}) for a list of them) or a hexadecimal color | |
560 | specification of the form @samp{#@var{rr}@var{gg}@var{bb}}. | |
561 | (@samp{#000000} is black, @samp{#ff0000} is red, @samp{#00ff00} is | |
562 | green, @samp{#0000ff} is blue, and @samp{#ffffff} is white.) On a | |
563 | black-and-white display, the colors you can use for the background are | |
564 | @samp{black}, @samp{white}, @samp{gray}, @samp{gray1}, and | |
565 | @samp{gray3}. Emacs supports these shades of gray by using background | |
566 | stipple patterns instead of a color. | |
6bf7aab6 DL |
567 | |
568 | Setting, saving and resetting a face work like the same operations for | |
89fa0de4 | 569 | variables (@pxref{Changing a Variable}). |
6bf7aab6 DL |
570 | |
571 | A face can specify different appearances for different types of | |
572 | display. For example, a face can make text red on a color display, but | |
573 | use a bold font on a monochrome display. To specify multiple | |
6b46232e | 574 | appearances for a face, select @samp{Show all display specs} in the menu you |
6bf7aab6 DL |
575 | get from invoking @samp{[State]}. |
576 | ||
577 | @findex modify-face | |
578 | Another more basic way to set the attributes of a specific face is | |
579 | with @kbd{M-x modify-face}. This command reads the name of a face, then | |
580 | reads the attributes one by one. For the color and stipple attributes, | |
581 | the attribute's current value is the default---type just @key{RET} if | |
582 | you don't want to change that attribute. Type @samp{none} if you want | |
583 | to clear out the attribute. | |
584 | ||
585 | @node Specific Customization | |
bba2a48e | 586 | @subsection Customizing Specific Items |
6bf7aab6 DL |
587 | |
588 | Instead of finding the options you want to change by moving down | |
89fa0de4 RS |
589 | through the structure of groups, you can specify the particular variable, |
590 | face, or group that you want to customize. | |
6bf7aab6 DL |
591 | |
592 | @table @kbd | |
89fa0de4 RS |
593 | @item M-x customize-variable @key{RET} @var{variable} @key{RET} |
594 | Set up a customization buffer with just one variable, @var{variable}. | |
6bf7aab6 DL |
595 | @item M-x customize-face @key{RET} @var{face} @key{RET} |
596 | Set up a customization buffer with just one face, @var{face}. | |
597 | @item M-x customize-group @key{RET} @var{group} @key{RET} | |
598 | Set up a customization buffer with just one group, @var{group}. | |
599 | @item M-x customize-apropos @key{RET} @var{regexp} @key{RET} | |
89fa0de4 | 600 | Set up a customization buffer with all the variables, faces and groups |
6bf7aab6 DL |
601 | that match @var{regexp}. |
602 | @item M-x customize-changed-options @key{RET} @var{version} @key{RET} | |
89fa0de4 | 603 | Set up a customization buffer with all the variables, faces and groups |
6bf7aab6 | 604 | whose meaning has changed since Emacs version @var{version}. |
177c0ea7 | 605 | @item M-x customize-saved |
89fa0de4 | 606 | Set up a customization buffer containing all variables and faces that you |
6bf7aab6 DL |
607 | have saved with customization buffers. |
608 | @item M-x customize-customized | |
89fa0de4 | 609 | Set up a customization buffer containing all variables and faces that you |
6bf7aab6 DL |
610 | have customized but not saved. |
611 | @end table | |
612 | ||
89fa0de4 RS |
613 | @findex customize-variable |
614 | If you want to alter a particular variable with the customization | |
615 | buffer, and you know its name, you can use the command @kbd{M-x | |
616 | customize-variable} and specify the variable name. This sets up the | |
617 | customization buffer with just one variable---the one that you asked | |
618 | for. Editing, setting and saving the value work as described above, | |
619 | but only for the specified variable. | |
6bf7aab6 DL |
620 | |
621 | @findex customize-face | |
622 | Likewise, you can modify a specific face, chosen by name, using | |
0a5ec0fe RS |
623 | @kbd{M-x customize-face}. By default it operates on the face used |
624 | on the character after point. | |
6bf7aab6 DL |
625 | |
626 | @findex customize-group | |
627 | You can also set up the customization buffer with a specific group, | |
628 | using @kbd{M-x customize-group}. The immediate contents of the chosen | |
bba2a48e | 629 | group, including user options, faces, and other groups, all appear |
6bf7aab6 DL |
630 | as well. However, these subgroups' own contents start out hidden. You |
631 | can show their contents in the usual way, by invoking @samp{[Show]}. | |
632 | ||
633 | @findex customize-apropos | |
634 | To control more precisely what to customize, you can use @kbd{M-x | |
635 | customize-apropos}. You specify a regular expression as argument; then | |
636 | all options, faces and groups whose names match this regular expression | |
637 | are set up in the customization buffer. If you specify an empty regular | |
638 | expression, this includes @emph{all} groups, options and faces in the | |
639 | customization buffer (but that takes a long time). | |
640 | ||
641 | @findex customize-changed-options | |
642 | When you upgrade to a new Emacs version, you might want to customize | |
643 | new options and options whose meanings or default values have changed. | |
644 | To do this, use @kbd{M-x customize-changed-options} and specify a | |
645 | previous Emacs version number using the minibuffer. It creates a | |
646 | customization buffer which shows all the options (and groups) whose | |
647 | definitions have been changed since the specified version. | |
648 | ||
649 | @findex customize-saved | |
650 | @findex customize-customized | |
89fa0de4 RS |
651 | If you change option values and then decide the change was a |
652 | mistake, you can use two special commands to revisit your previous | |
653 | changes. Use @kbd{M-x customize-saved} to look at the options that | |
654 | you have saved. Use @kbd{M-x customize-customized} to look at the | |
655 | options that you have set but not saved. | |
6bf7aab6 | 656 | |
4242b8d6 CY |
657 | @node Custom Themes |
658 | @subsection Customization Themes | |
659 | @cindex custom themes | |
660 | ||
661 | @dfn{Custom themes} are collections of customized options that can be | |
662 | enabled or disabled as a unit. You can use Custom themes to switch | |
663 | quickly and easily between various collections of settings, and to | |
664 | transfer such collections from one computer to another. | |
665 | ||
666 | @findex customize-create-theme | |
667 | To define a Custom theme, use the command | |
668 | @kbd{M-x customize-create-theme}, which brings up a buffer named | |
669 | @samp{*New Custom Theme*}. At the top of the buffer is an editable | |
670 | field where you can specify the name of the theme. To add a | |
671 | customization option to the theme, click on the @samp{INS} button to | |
672 | open up a field where you can insert the name of the option. The | |
673 | current value of that option is applied to the theme. After adding as | |
674 | many options as you like, click on @samp{Done} to save the Custom | |
675 | theme. | |
676 | ||
677 | @vindex custom-theme-directory | |
678 | Saving a Custom theme named @var{foo} writes its definition into the | |
679 | file @file{@var{foo}-theme.el}, in the directory @file{~/.emacs.d/} | |
680 | (you can specify the directory by setting | |
681 | @code{custom-theme-directory}). | |
682 | ||
683 | @findex load-theme | |
684 | @findex enable-theme | |
685 | @findex disable-theme | |
686 | You can load the themes you've previously defined with the command | |
687 | @code{load-theme}. It prompts for a theme name in the minibuffer, | |
688 | then loads that theme if it isn't already loaded. It also | |
689 | @dfn{enables} the theme, which means putting its settings into effect. | |
690 | An enabled theme can be @dfn{disabled} with the command | |
691 | @kbd{M-x disable-theme}; this returns the options specified in the | |
692 | theme to their original values. To re-enable the theme, use the | |
693 | command @kbd{M-x enable-theme}. | |
694 | ||
695 | To enable a Custom theme named @var{foo} whenever Emacs is started up, | |
696 | add the line @code{(load-theme '@var{foo})} to your @file{.emacs} file | |
697 | (@pxref{Init File}). | |
698 | ||
699 | Enabling a custom theme does not disable the themes already enabled; | |
700 | instead, they are all enabled together. If two enabled Custom themes | |
701 | specify different values for an option, the last theme to be enabled | |
702 | takes effect. | |
703 | ||
704 | The options that you set in the ordinary customization buffer | |
705 | (@pxref{Easy Customization}) are also considered part of a Custom | |
706 | theme, called @samp{user}. The @samp{user} theme is always enabled, | |
707 | and always takes precedence over all other enabled Custom themes. | |
708 | Additionally, the @samp{user} theme is recorded in your @file{.emacs} | |
709 | file, rather than a @file{user-theme.el} file. | |
710 | ||
bba2a48e RS |
711 | @node Variables |
712 | @section Variables | |
713 | @cindex variable | |
714 | @cindex option, user | |
715 | @cindex user option | |
716 | ||
717 | A @dfn{variable} is a Lisp symbol which has a value. The symbol's | |
718 | name is also called the name of the variable. A variable name can | |
719 | contain any characters that can appear in a file, but conventionally | |
720 | variable names consist of words separated by hyphens. A variable can | |
721 | have a documentation string which describes what kind of value it should | |
722 | have and how the value will be used. | |
723 | ||
724 | Lisp allows any variable to have any kind of value, but most variables | |
725 | that Emacs uses need a value of a certain type. Often the value should | |
726 | always be a string, or should always be a number. Sometimes we say that a | |
727 | certain feature is turned on if a variable is ``non-@code{nil},'' meaning | |
728 | that if the variable's value is @code{nil}, the feature is off, but the | |
729 | feature is on for @emph{any} other value. The conventional value to use to | |
730 | turn on the feature---since you have to pick one particular value when you | |
731 | set the variable---is @code{t}. | |
732 | ||
733 | Emacs uses many Lisp variables for internal record keeping, but the | |
89fa0de4 RS |
734 | most interesting variables for a non-programmer user are those that |
735 | are also @dfn{user options}, the variables that are meant for users to | |
736 | change. Each user option that you can set with the customization | |
737 | buffer is (if it is not a face) in fact a Lisp variable. Emacs does | |
738 | not (usually) change the values of these variables; instead, you set | |
739 | the values, and thereby alter and control the behavior of certain | |
af1b4255 RS |
740 | Emacs commands. Use of the customization buffer is explained above |
741 | (@pxref{Easy Customization}); here we describe other aspects of Emacs | |
742 | variables. | |
bba2a48e RS |
743 | |
744 | @menu | |
745 | * Examining:: Examining or setting one variable's value. | |
746 | * Hooks:: Hook variables let you specify programs for parts | |
747 | of Emacs to run on particular occasions. | |
748 | * Locals:: Per-buffer values of variables. | |
749 | * File Variables:: How files can specify variable values. | |
750 | @end menu | |
751 | ||
752 | @node Examining | |
753 | @subsection Examining and Setting Variables | |
754 | @cindex setting variables | |
755 | ||
756 | @table @kbd | |
757 | @item C-h v @var{var} @key{RET} | |
758 | Display the value and documentation of variable @var{var} | |
759 | (@code{describe-variable}). | |
760 | @item M-x set-variable @key{RET} @var{var} @key{RET} @var{value} @key{RET} | |
761 | Change the value of variable @var{var} to @var{value}. | |
762 | @end table | |
763 | ||
764 | To examine the value of a single variable, use @kbd{C-h v} | |
765 | (@code{describe-variable}), which reads a variable name using the | |
766 | minibuffer, with completion. It displays both the value and the | |
767 | documentation of the variable. For example, | |
768 | ||
769 | @example | |
770 | C-h v fill-column @key{RET} | |
771 | @end example | |
772 | ||
773 | @noindent | |
774 | displays something like this: | |
775 | ||
776 | @smallexample | |
777 | fill-column's value is 70 | |
778 | ||
779 | Documentation: | |
780 | *Column beyond which automatic line-wrapping should happen. | |
781 | Automatically becomes buffer-local when set in any fashion. | |
782 | @end smallexample | |
783 | ||
784 | @noindent | |
785 | The star at the beginning of the documentation indicates that this | |
786 | variable is a user option. @kbd{C-h v} is not restricted to user | |
787 | options; it allows any variable name. | |
788 | ||
789 | @findex set-variable | |
89fa0de4 RS |
790 | The most convenient way to set a specific user option variable is |
791 | with @kbd{M-x set-variable}. This reads the variable name with the | |
792 | minibuffer (with completion), and then reads a Lisp expression for the | |
793 | new value using the minibuffer a second time. For example, | |
bba2a48e RS |
794 | |
795 | @example | |
796 | M-x set-variable @key{RET} fill-column @key{RET} 75 @key{RET} | |
797 | @end example | |
798 | ||
799 | @noindent | |
800 | sets @code{fill-column} to 75. | |
801 | ||
802 | @kbd{M-x set-variable} is limited to user option variables, but you can | |
803 | set any variable with a Lisp expression, using the function @code{setq}. | |
804 | Here is a @code{setq} expression to set @code{fill-column}: | |
805 | ||
806 | @example | |
807 | (setq fill-column 75) | |
808 | @end example | |
809 | ||
810 | To execute an expression like this one, go to the @samp{*scratch*} | |
811 | buffer, type in the expression, and then type @kbd{C-j}. @xref{Lisp | |
812 | Interaction}. | |
813 | ||
814 | Setting variables, like all means of customizing Emacs except where | |
af1b4255 RS |
815 | otherwise stated, affects only the current Emacs session. The only |
816 | way to alter the variable in future sessions is to put something in | |
817 | the @file{~/.emacs} file to set it those sessions (@pxref{Init File}). | |
bba2a48e | 818 | |
6bf7aab6 DL |
819 | @node Hooks |
820 | @subsection Hooks | |
821 | @cindex hook | |
6bf7aab6 DL |
822 | @cindex running a hook |
823 | ||
824 | @dfn{Hooks} are an important mechanism for customization of Emacs. A | |
825 | hook is a Lisp variable which holds a list of functions, to be called on | |
826 | some well-defined occasion. (This is called @dfn{running the hook}.) | |
827 | The individual functions in the list are called the @dfn{hook functions} | |
828 | of the hook. With rare exceptions, hooks in Emacs are empty when Emacs | |
829 | starts up, so the only hook functions in any given hook are the ones you | |
830 | explicitly put there as customization. | |
831 | ||
832 | Most major modes run one or more @dfn{mode hooks} as the last step of | |
833 | initialization. This makes it easy for you to customize the behavior of | |
834 | the mode, by setting up a hook function to override the local variable | |
835 | assignments already made by the mode. But hooks are also used in other | |
836 | contexts. For example, the hook @code{suspend-hook} runs just before | |
837 | Emacs suspends itself (@pxref{Exiting}). | |
838 | ||
839 | @cindex normal hook | |
840 | Most Emacs hooks are @dfn{normal hooks}. This means that running the | |
841 | hook operates by calling all the hook functions, unconditionally, with | |
842 | no arguments. We have made an effort to keep most hooks normal so that | |
843 | you can use them in a uniform way. Every variable in Emacs whose name | |
844 | ends in @samp{-hook} is a normal hook. | |
845 | ||
846 | @cindex abnormal hook | |
847 | There are also a few @dfn{abnormal hooks}. These variables' names end | |
848 | in @samp{-hooks} or @samp{-functions}, instead of @samp{-hook}. What | |
849 | makes these hooks abnormal is that there is something peculiar about the | |
850 | way its functions are called---perhaps they are given arguments, or | |
851 | perhaps the values they return are used in some way. For example, | |
f2aa473a | 852 | @code{find-file-not-found-functions} (@pxref{Visiting}) is abnormal because |
6bf7aab6 DL |
853 | as soon as one hook function returns a non-@code{nil} value, the rest |
854 | are not called at all. The documentation of each abnormal hook variable | |
855 | explains in detail what is peculiar about it. | |
856 | ||
2038519d RS |
857 | You can set a hook variable with @code{setq} like any other Lisp |
858 | variable, but the recommended way to add a hook function to a hook | |
859 | (either normal or abnormal) is by calling @code{add-hook}. You can | |
860 | specify any valid Lisp function as the hook function, provided it can | |
861 | handle the proper number of arguments (zero arguments, in the case of | |
862 | a normal hook). Of course, not every Lisp function is @emph{useful} | |
863 | in any particular hook. | |
6bf7aab6 DL |
864 | |
865 | For example, here's how to set up a hook to turn on Auto Fill mode | |
866 | when entering Text mode and other modes based on Text mode: | |
867 | ||
868 | @example | |
869 | (add-hook 'text-mode-hook 'turn-on-auto-fill) | |
870 | @end example | |
871 | ||
872 | The next example shows how to use a hook to customize the indentation | |
873 | of C code. (People often have strong personal preferences for one | |
874 | format compared to another.) Here the hook function is an anonymous | |
875 | lambda expression. | |
876 | ||
877 | @example | |
878 | @group | |
879 | (setq my-c-style | |
880 | '((c-comment-only-line-offset . 4) | |
881 | @end group | |
882 | @group | |
883 | (c-cleanup-list . (scope-operator | |
884 | empty-defun-braces | |
885 | defun-close-semi)) | |
886 | @end group | |
887 | @group | |
888 | (c-offsets-alist . ((arglist-close . c-lineup-arglist) | |
889 | (substatement-open . 0))))) | |
890 | @end group | |
891 | ||
892 | @group | |
893 | (add-hook 'c-mode-common-hook | |
bc49c316 DL |
894 | '(lambda () |
895 | (c-add-style "my-style" my-c-style t))) | |
6bf7aab6 DL |
896 | @end group |
897 | @end example | |
898 | ||
899 | It is best to design your hook functions so that the order in which | |
900 | they are executed does not matter. Any dependence on the order is | |
901 | ``asking for trouble.'' However, the order is predictable: the most | |
902 | recently added hook functions are executed first. | |
903 | ||
2038519d RS |
904 | If you play with adding various different versions of a hook |
905 | function by calling @code{add-hook} over and over, remember that all | |
c04a2eab RS |
906 | the versions you added will remain in the hook variable together. You |
907 | can clear out individual functions with @code{remove-hook}, or do | |
908 | @code{(setq @var{hook-variable} nil)} to remove everything. | |
2038519d | 909 | |
6bf7aab6 DL |
910 | @node Locals |
911 | @subsection Local Variables | |
912 | ||
913 | @table @kbd | |
914 | @item M-x make-local-variable @key{RET} @var{var} @key{RET} | |
915 | Make variable @var{var} have a local value in the current buffer. | |
916 | @item M-x kill-local-variable @key{RET} @var{var} @key{RET} | |
917 | Make variable @var{var} use its global value in the current buffer. | |
918 | @item M-x make-variable-buffer-local @key{RET} @var{var} @key{RET} | |
919 | Mark variable @var{var} so that setting it will make it local to the | |
920 | buffer that is current at that time. | |
921 | @end table | |
922 | ||
923 | @cindex local variables | |
924 | Almost any variable can be made @dfn{local} to a specific Emacs | |
925 | buffer. This means that its value in that buffer is independent of its | |
926 | value in other buffers. A few variables are always local in every | |
927 | buffer. Every other Emacs variable has a @dfn{global} value which is in | |
928 | effect in all buffers that have not made the variable local. | |
929 | ||
930 | @findex make-local-variable | |
931 | @kbd{M-x make-local-variable} reads the name of a variable and makes it | |
932 | local to the current buffer. Further changes in this buffer will not | |
933 | affect others, and further changes in the global value will not affect this | |
934 | buffer. | |
935 | ||
936 | @findex make-variable-buffer-local | |
937 | @cindex per-buffer variables | |
938 | @kbd{M-x make-variable-buffer-local} reads the name of a variable and | |
939 | changes the future behavior of the variable so that it will become local | |
940 | automatically when it is set. More precisely, once a variable has been | |
941 | marked in this way, the usual ways of setting the variable automatically | |
942 | do @code{make-local-variable} first. We call such variables | |
943 | @dfn{per-buffer} variables. | |
944 | ||
945 | Major modes (@pxref{Major Modes}) always make variables local to the | |
946 | buffer before setting the variables. This is why changing major modes | |
947 | in one buffer has no effect on other buffers. Minor modes also work by | |
948 | setting variables---normally, each minor mode has one controlling | |
949 | variable which is non-@code{nil} when the mode is enabled (@pxref{Minor | |
950 | Modes}). For most minor modes, the controlling variable is per buffer. | |
951 | ||
952 | Emacs contains a number of variables that are always per-buffer. | |
953 | These include @code{abbrev-mode}, @code{auto-fill-function}, | |
954 | @code{case-fold-search}, @code{comment-column}, @code{ctl-arrow}, | |
955 | @code{fill-column}, @code{fill-prefix}, @code{indent-tabs-mode}, | |
956 | @code{left-margin}, @code{mode-line-format}, @code{overwrite-mode}, | |
957 | @code{selective-display-ellipses}, @code{selective-display}, | |
958 | @code{tab-width}, and @code{truncate-lines}. Some other variables are | |
959 | always local in every buffer, but they are used for internal | |
960 | purposes.@refill | |
961 | ||
962 | A few variables cannot be local to a buffer because they are always | |
963 | local to each display instead (@pxref{Multiple Displays}). If you try to | |
964 | make one of these variables buffer-local, you'll get an error message. | |
965 | ||
966 | @findex kill-local-variable | |
967 | @kbd{M-x kill-local-variable} reads the name of a variable and makes | |
968 | it cease to be local to the current buffer. The global value of the | |
969 | variable henceforth is in effect in this buffer. Setting the major mode | |
970 | kills all the local variables of the buffer except for a few variables | |
971 | specially marked as @dfn{permanent locals}. | |
972 | ||
973 | @findex setq-default | |
974 | To set the global value of a variable, regardless of whether the | |
975 | variable has a local value in the current buffer, you can use the Lisp | |
976 | construct @code{setq-default}. This construct is used just like | |
977 | @code{setq}, but it sets variables' global values instead of their local | |
978 | values (if any). When the current buffer does have a local value, the | |
979 | new global value may not be visible until you switch to another buffer. | |
980 | Here is an example: | |
981 | ||
982 | @example | |
983 | (setq-default fill-column 75) | |
984 | @end example | |
985 | ||
986 | @noindent | |
987 | @code{setq-default} is the only way to set the global value of a variable | |
988 | that has been marked with @code{make-variable-buffer-local}. | |
989 | ||
990 | @findex default-value | |
991 | Lisp programs can use @code{default-value} to look at a variable's | |
992 | default value. This function takes a symbol as argument and returns its | |
993 | default value. The argument is evaluated; usually you must quote it | |
994 | explicitly. For example, here's how to obtain the default value of | |
995 | @code{fill-column}: | |
996 | ||
997 | @example | |
998 | (default-value 'fill-column) | |
999 | @end example | |
1000 | ||
1001 | @node File Variables | |
1002 | @subsection Local Variables in Files | |
1003 | @cindex local variables in files | |
1004 | @cindex file local variables | |
1005 | ||
1006 | A file can specify local variable values for use when you edit the | |
1007 | file with Emacs. Visiting the file checks for local variable | |
1008 | specifications; it automatically makes these variables local to the | |
1009 | buffer, and sets them to the values specified in the file. | |
1010 | ||
1011 | There are two ways to specify local variable values: in the first | |
1012 | line, or with a local variables list. Here's how to specify them in the | |
1013 | first line: | |
1014 | ||
1015 | @example | |
1016 | -*- mode: @var{modename}; @var{var}: @var{value}; @dots{} -*- | |
1017 | @end example | |
1018 | ||
1019 | @noindent | |
1020 | You can specify any number of variables/value pairs in this way, each | |
1021 | pair with a colon and semicolon as shown above. @code{mode: | |
1022 | @var{modename};} specifies the major mode; this should come first in the | |
1023 | line. The @var{value}s are not evaluated; they are used literally. | |
1024 | Here is an example that specifies Lisp mode and sets two variables with | |
1025 | numeric values: | |
1026 | ||
1027 | @smallexample | |
6a9a44bf | 1028 | ;; -*- mode: Lisp; fill-column: 75; comment-column: 50; -*- |
6bf7aab6 DL |
1029 | @end smallexample |
1030 | ||
1031 | You can also specify the coding system for a file in this way: just | |
1032 | specify a value for the ``variable'' named @code{coding}. The ``value'' | |
1033 | must be a coding system name that Emacs recognizes. @xref{Coding | |
2e66e5b7 RS |
1034 | Systems}. @w{@samp{unibyte: t}} specifies unibyte loading for a |
1035 | particular Lisp file. @xref{Enabling Multibyte}. | |
6bf7aab6 | 1036 | |
07eab3c3 EZ |
1037 | The @code{eval} pseudo-variable, described below, can be specified in |
1038 | the first line as well. | |
1039 | ||
1040 | @cindex shell scripts, and local file variables | |
1041 | In shell scripts, the first line is used to identify the script | |
d0960fb3 | 1042 | interpreter, so you cannot put any local variables there. To accommodate |
07eab3c3 EZ |
1043 | for this, when Emacs visits a shell script, it looks for local variable |
1044 | specifications in the @emph{second} line. | |
1045 | ||
6bf7aab6 DL |
1046 | A @dfn{local variables list} goes near the end of the file, in the |
1047 | last page. (It is often best to put it on a page by itself.) The local | |
1048 | variables list starts with a line containing the string @samp{Local | |
1049 | Variables:}, and ends with a line containing the string @samp{End:}. In | |
1050 | between come the variable names and values, one set per line, as | |
1051 | @samp{@var{variable}:@: @var{value}}. The @var{value}s are not | |
1052 | evaluated; they are used literally. If a file has both a local | |
1053 | variables list and a @samp{-*-} line, Emacs processes @emph{everything} | |
1054 | in the @samp{-*-} line first, and @emph{everything} in the local | |
1055 | variables list afterward. | |
1056 | ||
1057 | Here is an example of a local variables list: | |
1058 | ||
1059 | @example | |
1060 | ;;; Local Variables: *** | |
1061 | ;;; mode:lisp *** | |
1062 | ;;; comment-column:0 *** | |
1063 | ;;; comment-start: ";;; " *** | |
1064 | ;;; comment-end:"***" *** | |
1065 | ;;; End: *** | |
1066 | @end example | |
1067 | ||
1068 | As you see, each line starts with the prefix @samp{;;; } and each line | |
1069 | ends with the suffix @samp{ ***}. Emacs recognizes these as the prefix | |
1070 | and suffix based on the first line of the list, by finding them | |
1071 | surrounding the magic string @samp{Local Variables:}; then it | |
1072 | automatically discards them from the other lines of the list. | |
1073 | ||
1074 | The usual reason for using a prefix and/or suffix is to embed the | |
1075 | local variables list in a comment, so it won't confuse other programs | |
1076 | that the file is intended as input for. The example above is for a | |
1077 | language where comment lines start with @samp{;;; } and end with | |
1078 | @samp{***}; the local values for @code{comment-start} and | |
2038519d RS |
1079 | @code{comment-end} customize the rest of Emacs for this unusual |
1080 | syntax. Don't use a prefix (or a suffix) if you don't need one. | |
1081 | ||
1082 | If you write a multi-line string value, you should put the prefix | |
1083 | and suffix on each line, even lines that start or end within the | |
1084 | string. They will be stripped off for processing the list. If you | |
1085 | want to split a long string across multiple lines of the file, you can | |
1086 | use backslash-newline, which is ignored in Lisp string constants. | |
1087 | Here's an example of doing this: | |
1088 | ||
1089 | @example | |
1090 | # Local Variables: | |
1091 | # compile-command: "cc foo.c -Dfoo=bar -Dhack=whatever \ | |
1092 | # -Dmumble=blaah" | |
1093 | # End: | |
1094 | @end example | |
6bf7aab6 | 1095 | |
2e66e5b7 | 1096 | Some ``variable names'' have special meanings in a local variables |
3c338c5f RS |
1097 | list. Specifying the ``variable'' @code{mode} really sets the major |
1098 | mode, while any value specified for the ``variable'' @code{eval} is | |
1099 | simply evaluated as an expression (its value is ignored). A value for | |
1100 | @code{coding} specifies the coding system for character code | |
1101 | conversion of this file, and a value of @code{t} for @code{unibyte} | |
1102 | says to visit the file in a unibyte buffer. These four ``variables'' | |
1103 | are not really variables; setting them in any other context has no | |
1104 | special meaning. | |
1105 | ||
1106 | @emph{If @code{mode} is used to set a major mode, it should be the | |
1107 | first ``variable'' in the list.} Otherwise, the entries that precede | |
1108 | it will usually be ignored, since most modes kill all local variables | |
1109 | as part of their initialization. | |
1110 | ||
1111 | You can use the @code{mode} ``variable'' to set minor modes as well | |
1112 | as the major modes; in fact, you can use it more than once, first to | |
1113 | set the major mode and then to set minor modes which are specific to | |
1114 | particular buffers. But most minor modes should not be specified in | |
1115 | the file at all, regardless of how, because they represent user | |
1116 | preferences. | |
6bf7aab6 DL |
1117 | |
1118 | For example, you may be tempted to try to turn on Auto Fill mode with | |
1119 | a local variable list. That is a mistake. The choice of Auto Fill mode | |
1120 | or not is a matter of individual taste, not a matter of the contents of | |
1121 | particular files. If you want to use Auto Fill, set up major mode hooks | |
1122 | with your @file{.emacs} file to turn it on (when appropriate) for you | |
1123 | alone (@pxref{Init File}). Don't use a local variable list to impose | |
1124 | your taste on everyone. | |
1125 | ||
1126 | The start of the local variables list must be no more than 3000 | |
1127 | characters from the end of the file, and must be in the last page if the | |
1128 | file is divided into pages. Otherwise, Emacs will not notice it is | |
1129 | there. The purpose of this rule is so that a stray @samp{Local | |
1130 | Variables:}@: not in the last page does not confuse Emacs, and so that | |
1131 | visiting a long file that is all one page and has no local variables | |
1132 | list need not take the time to search the whole file. | |
1133 | ||
1134 | Use the command @code{normal-mode} to reset the local variables and | |
1135 | major mode of a buffer according to the file name and contents, | |
1136 | including the local variables list if any. @xref{Choosing Modes}. | |
1137 | ||
1138 | @findex enable-local-variables | |
1139 | The variable @code{enable-local-variables} controls whether to process | |
1140 | local variables in files, and thus gives you a chance to override them. | |
1141 | Its default value is @code{t}, which means do process local variables in | |
1142 | files. If you set the value to @code{nil}, Emacs simply ignores local | |
1143 | variables in files. Any other value says to query you about each file | |
1144 | that has local variables, showing you the local variable specifications | |
1145 | so you can judge. | |
1146 | ||
1147 | @findex enable-local-eval | |
1148 | The @code{eval} ``variable,'' and certain actual variables, create a | |
1149 | special risk; when you visit someone else's file, local variable | |
1150 | specifications for these could affect your Emacs in arbitrary ways. | |
89fa0de4 | 1151 | Therefore, the variable @code{enable-local-eval} controls whether Emacs |
6bf7aab6 DL |
1152 | processes @code{eval} variables, as well variables with names that end |
1153 | in @samp{-hook}, @samp{-hooks}, @samp{-function} or @samp{-functions}, | |
89fa0de4 | 1154 | and certain other variables. The three possibilities for the variable's |
6bf7aab6 DL |
1155 | value are @code{t}, @code{nil}, and anything else, just as for |
1156 | @code{enable-local-variables}. The default is @code{maybe}, which is | |
1157 | neither @code{t} nor @code{nil}, so normally Emacs does ask for | |
1158 | confirmation about file settings for these variables. | |
1159 | ||
d8f8d1bb KS |
1160 | @findex safe-local-eval-forms |
1161 | The @code{safe-local-eval-forms} is a customizable list of eval | |
1162 | forms which are safe to eval, so Emacs should not ask for | |
1163 | confirmation to evaluate these forms, even if | |
1164 | @code{enable-local-variables} says to ask for confirmation in general. | |
1165 | ||
6bf7aab6 DL |
1166 | @node Key Bindings |
1167 | @section Customizing Key Bindings | |
1168 | @cindex key bindings | |
1169 | ||
1170 | This section describes @dfn{key bindings}, which map keys to commands, | |
1171 | and @dfn{keymaps}, which record key bindings. It also explains how | |
1172 | to customize key bindings. | |
1173 | ||
1174 | Recall that a command is a Lisp function whose definition provides for | |
1175 | interactive use. Like every Lisp function, a command has a function | |
1176 | name which usually consists of lower-case letters and hyphens. | |
1177 | ||
1178 | @menu | |
1179 | * Keymaps:: Generalities. The global keymap. | |
1180 | * Prefix Keymaps:: Keymaps for prefix keys. | |
1181 | * Local Keymaps:: Major and minor modes have their own keymaps. | |
1182 | * Minibuffer Maps:: The minibuffer uses its own local keymaps. | |
1183 | * Rebinding:: How to redefine one key's meaning conveniently. | |
1184 | * Init Rebinding:: Rebinding keys with your init file, @file{.emacs}. | |
1185 | * Function Keys:: Rebinding terminal function keys. | |
1186 | * Named ASCII Chars:: Distinguishing @key{TAB} from @kbd{C-i}, and so on. | |
76dd3692 | 1187 | * Non-ASCII Rebinding:: Rebinding non-@acronym{ASCII} characters such as Latin-1. |
6bf7aab6 DL |
1188 | * Mouse Buttons:: Rebinding mouse buttons in Emacs. |
1189 | * Disabling:: Disabling a command means confirmation is required | |
1190 | before it can be executed. This is done to protect | |
1191 | beginners from surprises. | |
1192 | @end menu | |
1193 | ||
1194 | @node Keymaps | |
1195 | @subsection Keymaps | |
1196 | @cindex keymap | |
1197 | ||
1198 | The bindings between key sequences and command functions are recorded | |
1199 | in data structures called @dfn{keymaps}. Emacs has many of these, each | |
1200 | used on particular occasions. | |
1201 | ||
1202 | Recall that a @dfn{key sequence} (@dfn{key}, for short) is a sequence | |
1203 | of @dfn{input events} that have a meaning as a unit. Input events | |
1204 | include characters, function keys and mouse buttons---all the inputs | |
1205 | that you can send to the computer with your terminal. A key sequence | |
1206 | gets its meaning from its @dfn{binding}, which says what command it | |
1207 | runs. The function of keymaps is to record these bindings. | |
1208 | ||
1209 | @cindex global keymap | |
1210 | The @dfn{global} keymap is the most important keymap because it is | |
1211 | always in effect. The global keymap defines keys for Fundamental mode; | |
1212 | most of these definitions are common to most or all major modes. Each | |
1213 | major or minor mode can have its own keymap which overrides the global | |
1214 | definitions of some keys. | |
1215 | ||
1216 | For example, a self-inserting character such as @kbd{g} is | |
1217 | self-inserting because the global keymap binds it to the command | |
1218 | @code{self-insert-command}. The standard Emacs editing characters such | |
1219 | as @kbd{C-a} also get their standard meanings from the global keymap. | |
1220 | Commands to rebind keys, such as @kbd{M-x global-set-key}, actually work | |
1221 | by storing the new binding in the proper place in the global map. | |
1222 | @xref{Rebinding}. | |
1223 | ||
1224 | Meta characters work differently; Emacs translates each Meta | |
1225 | character into a pair of characters starting with @key{ESC}. When you | |
1226 | type the character @kbd{M-a} in a key sequence, Emacs replaces it with | |
1227 | @kbd{@key{ESC} a}. A meta key comes in as a single input event, but | |
1228 | becomes two events for purposes of key bindings. The reason for this is | |
1229 | historical, and we might change it someday. | |
1230 | ||
1231 | @cindex function key | |
1232 | Most modern keyboards have function keys as well as character keys. | |
1233 | Function keys send input events just as character keys do, and keymaps | |
1234 | can have bindings for them. | |
1235 | ||
af1b4255 | 1236 | On text terminals, typing a function key actually sends the computer a |
6bf7aab6 DL |
1237 | sequence of characters; the precise details of the sequence depends on |
1238 | which function key and on the model of terminal you are using. (Often | |
1239 | the sequence starts with @kbd{@key{ESC} [}.) If Emacs understands your | |
1240 | terminal type properly, it recognizes the character sequences forming | |
1241 | function keys wherever they occur in a key sequence (not just at the | |
1242 | beginning). Thus, for most purposes, you can pretend the function keys | |
1243 | reach Emacs directly and ignore their encoding as character sequences. | |
1244 | ||
1245 | @cindex mouse | |
1246 | Mouse buttons also produce input events. These events come with other | |
1247 | data---the window and position where you pressed or released the button, | |
1248 | and a time stamp. But only the choice of button matters for key | |
1249 | bindings; the other data matters only if a command looks at it. | |
1250 | (Commands designed for mouse invocation usually do look at the other | |
1251 | data.) | |
1252 | ||
1253 | A keymap records definitions for single events. Interpreting a key | |
1254 | sequence of multiple events involves a chain of keymaps. The first | |
1255 | keymap gives a definition for the first event; this definition is | |
1256 | another keymap, which is used to look up the second event in the | |
1257 | sequence, and so on. | |
1258 | ||
1259 | Key sequences can mix function keys and characters. For example, | |
1260 | @kbd{C-x @key{SELECT}} is meaningful. If you make @key{SELECT} a prefix | |
1261 | key, then @kbd{@key{SELECT} C-n} makes sense. You can even mix mouse | |
1262 | events with keyboard events, but we recommend against it, because such | |
03d48361 | 1263 | key sequences are inconvenient to use. |
6bf7aab6 | 1264 | |
03d48361 | 1265 | As a user, you can redefine any key; but it is usually best to stick |
3a2ceb9e RS |
1266 | to key sequences that consist of @kbd{C-c} followed by a letter (upper |
1267 | or lower case). These keys are ``reserved for users,'' so they won't | |
1268 | conflict with any properly designed Emacs extension. The function | |
1269 | keys @key{F5} through @key{F9} are also reserved for users. If you | |
1270 | redefine some other key, your definition may be overridden by certain | |
1271 | extensions or major modes which redefine the same key. | |
6bf7aab6 DL |
1272 | |
1273 | @node Prefix Keymaps | |
1274 | @subsection Prefix Keymaps | |
1275 | ||
1276 | A prefix key such as @kbd{C-x} or @key{ESC} has its own keymap, | |
1277 | which holds the definition for the event that immediately follows | |
1278 | that prefix. | |
1279 | ||
1280 | The definition of a prefix key is usually the keymap to use for | |
1281 | looking up the following event. The definition can also be a Lisp | |
1282 | symbol whose function definition is the following keymap; the effect is | |
1283 | the same, but it provides a command name for the prefix key that can be | |
1284 | used as a description of what the prefix key is for. Thus, the binding | |
1285 | of @kbd{C-x} is the symbol @code{Ctl-X-Prefix}, whose function | |
1286 | definition is the keymap for @kbd{C-x} commands. The definitions of | |
1287 | @kbd{C-c}, @kbd{C-x}, @kbd{C-h} and @key{ESC} as prefix keys appear in | |
1288 | the global map, so these prefix keys are always available. | |
1289 | ||
1290 | Aside from ordinary prefix keys, there is a fictitious ``prefix key'' | |
1291 | which represents the menu bar; see @ref{Menu Bar,,,elisp, The Emacs Lisp | |
1292 | Reference Manual}, for special information about menu bar key bindings. | |
1293 | Mouse button events that invoke pop-up menus are also prefix keys; see | |
1294 | @ref{Menu Keymaps,,,elisp, The Emacs Lisp Reference Manual}, for more | |
1295 | details. | |
1296 | ||
1297 | Some prefix keymaps are stored in variables with names: | |
1298 | ||
1299 | @itemize @bullet | |
1300 | @item | |
1301 | @vindex ctl-x-map | |
1302 | @code{ctl-x-map} is the variable name for the map used for characters that | |
1303 | follow @kbd{C-x}. | |
1304 | @item | |
1305 | @vindex help-map | |
1306 | @code{help-map} is for characters that follow @kbd{C-h}. | |
1307 | @item | |
1308 | @vindex esc-map | |
1309 | @code{esc-map} is for characters that follow @key{ESC}. Thus, all Meta | |
1310 | characters are actually defined by this map. | |
1311 | @item | |
1312 | @vindex ctl-x-4-map | |
1313 | @code{ctl-x-4-map} is for characters that follow @kbd{C-x 4}. | |
1314 | @item | |
1315 | @vindex mode-specific-map | |
1316 | @code{mode-specific-map} is for characters that follow @kbd{C-c}. | |
1317 | @end itemize | |
1318 | ||
1319 | @node Local Keymaps | |
1320 | @subsection Local Keymaps | |
1321 | ||
1322 | @cindex local keymap | |
1323 | So far we have explained the ins and outs of the global map. Major | |
1324 | modes customize Emacs by providing their own key bindings in @dfn{local | |
1325 | keymaps}. For example, C mode overrides @key{TAB} to make it indent the | |
1326 | current line for C code. Portions of text in the buffer can specify | |
1327 | their own keymaps to substitute for the keymap of the buffer's major | |
1328 | mode. | |
1329 | ||
1330 | @cindex minor mode keymap | |
1331 | Minor modes can also have local keymaps. Whenever a minor mode is | |
1332 | in effect, the definitions in its keymap override both the major | |
1333 | mode's local keymap and the global keymap. | |
1334 | ||
1335 | @vindex c-mode-map | |
1336 | @vindex lisp-mode-map | |
1337 | The local keymaps for Lisp mode and several other major modes always | |
1338 | exist even when not in use. These are kept in variables named | |
1339 | @code{lisp-mode-map} and so on. For major modes less often used, the | |
1340 | local keymap is normally constructed only when the mode is used for the | |
1341 | first time in a session. This is to save space. If you wish to change | |
1342 | one of these keymaps, you must use the major mode's @dfn{mode | |
1343 | hook}---see below. | |
1344 | ||
1345 | All minor mode keymaps are created in advance. There is no way to | |
1346 | defer their creation until the first time the minor mode is enabled. | |
1347 | ||
1348 | A local keymap can locally redefine a key as a prefix key by defining | |
1349 | it as a prefix keymap. If the key is also defined globally as a prefix, | |
1350 | then its local and global definitions (both keymaps) effectively | |
1351 | combine: both of them are used to look up the event that follows the | |
1352 | prefix key. Thus, if the mode's local keymap defines @kbd{C-c} as | |
1353 | another keymap, and that keymap defines @kbd{C-z} as a command, this | |
1354 | provides a local meaning for @kbd{C-c C-z}. This does not affect other | |
1355 | sequences that start with @kbd{C-c}; if those sequences don't have their | |
1356 | own local bindings, their global bindings remain in effect. | |
1357 | ||
1358 | Another way to think of this is that Emacs handles a multi-event key | |
1359 | sequence by looking in several keymaps, one by one, for a binding of the | |
1360 | whole key sequence. First it checks the minor mode keymaps for minor | |
1361 | modes that are enabled, then it checks the major mode's keymap, and then | |
1362 | it checks the global keymap. This is not precisely how key lookup | |
1363 | works, but it's good enough for understanding ordinary circumstances. | |
1364 | ||
1365 | @cindex rebinding major mode keys | |
4ea68fcc | 1366 | @findex define-key |
6bf7aab6 DL |
1367 | To change the local bindings of a major mode, you must change the |
1368 | mode's local keymap. Normally you must wait until the first time the | |
1369 | mode is used, because most major modes don't create their keymaps until | |
1370 | then. If you want to specify something in your @file{~/.emacs} file to | |
1371 | change a major mode's bindings, you must use the mode's mode hook to | |
1372 | delay the change until the mode is first used. | |
1373 | ||
1374 | For example, the command @code{texinfo-mode} to select Texinfo mode | |
1375 | runs the hook @code{texinfo-mode-hook}. Here's how you can use the hook | |
1376 | to add local bindings (not very useful, we admit) for @kbd{C-c n} and | |
1377 | @kbd{C-c p} in Texinfo mode: | |
1378 | ||
1379 | @example | |
1380 | (add-hook 'texinfo-mode-hook | |
5d9dd378 RS |
1381 | '(lambda () |
1382 | (define-key texinfo-mode-map "\C-cp" | |
1383 | 'backward-paragraph) | |
1384 | (define-key texinfo-mode-map "\C-cn" | |
1385 | 'forward-paragraph))) | |
6bf7aab6 DL |
1386 | @end example |
1387 | ||
1388 | @xref{Hooks}. | |
1389 | ||
1390 | @node Minibuffer Maps | |
1391 | @subsection Minibuffer Keymaps | |
1392 | ||
1393 | @cindex minibuffer keymaps | |
1394 | @vindex minibuffer-local-map | |
1395 | @vindex minibuffer-local-ns-map | |
1396 | @vindex minibuffer-local-completion-map | |
1397 | @vindex minibuffer-local-must-match-map | |
1398 | The minibuffer has its own set of local keymaps; they contain various | |
1399 | completion and exit commands. | |
1400 | ||
1401 | @itemize @bullet | |
1402 | @item | |
1403 | @code{minibuffer-local-map} is used for ordinary input (no completion). | |
1404 | @item | |
1405 | @code{minibuffer-local-ns-map} is similar, except that @key{SPC} exits | |
1406 | just like @key{RET}. This is used mainly for Mocklisp compatibility. | |
1407 | @item | |
1408 | @code{minibuffer-local-completion-map} is for permissive completion. | |
1409 | @item | |
1410 | @code{minibuffer-local-must-match-map} is for strict completion and | |
1411 | for cautious completion. | |
1412 | @end itemize | |
1413 | ||
1414 | @node Rebinding | |
1415 | @subsection Changing Key Bindings Interactively | |
1416 | @cindex key rebinding, this session | |
4946337d | 1417 | @cindex redefining keys, this session |
6bf7aab6 DL |
1418 | |
1419 | The way to redefine an Emacs key is to change its entry in a keymap. | |
1420 | You can change the global keymap, in which case the change is effective in | |
1421 | all major modes (except those that have their own overriding local | |
1422 | definitions for the same key). Or you can change the current buffer's | |
1423 | local map, which affects all buffers using the same major mode. | |
1424 | ||
1425 | @findex global-set-key | |
1426 | @findex local-set-key | |
1427 | @findex global-unset-key | |
1428 | @findex local-unset-key | |
1429 | @table @kbd | |
1430 | @item M-x global-set-key @key{RET} @var{key} @var{cmd} @key{RET} | |
1431 | Define @var{key} globally to run @var{cmd}. | |
1432 | @item M-x local-set-key @key{RET} @var{key} @var{cmd} @key{RET} | |
1433 | Define @var{key} locally (in the major mode now in effect) to run | |
1434 | @var{cmd}. | |
1435 | @item M-x global-unset-key @key{RET} @var{key} | |
1436 | Make @var{key} undefined in the global map. | |
1437 | @item M-x local-unset-key @key{RET} @var{key} | |
1438 | Make @var{key} undefined locally (in the major mode now in effect). | |
1439 | @end table | |
1440 | ||
1441 | For example, suppose you like to execute commands in a subshell within | |
1442 | an Emacs buffer, instead of suspending Emacs and executing commands in | |
1443 | your login shell. Normally, @kbd{C-z} is bound to the function | |
1444 | @code{suspend-emacs} (when not using the X Window System), but you can | |
1445 | change @kbd{C-z} to invoke an interactive subshell within Emacs, by | |
1446 | binding it to @code{shell} as follows: | |
1447 | ||
1448 | @example | |
1449 | M-x global-set-key @key{RET} C-z shell @key{RET} | |
1450 | @end example | |
1451 | ||
1452 | @noindent | |
1453 | @code{global-set-key} reads the command name after the key. After you | |
1454 | press the key, a message like this appears so that you can confirm that | |
1455 | you are binding the key you want: | |
1456 | ||
1457 | @example | |
177c0ea7 | 1458 | Set key C-z to command: |
6bf7aab6 DL |
1459 | @end example |
1460 | ||
1461 | You can redefine function keys and mouse events in the same way; just | |
1462 | type the function key or click the mouse when it's time to specify the | |
1463 | key to rebind. | |
1464 | ||
1465 | You can rebind a key that contains more than one event in the same | |
1466 | way. Emacs keeps reading the key to rebind until it is a complete key | |
1467 | (that is, not a prefix key). Thus, if you type @kbd{C-f} for | |
1468 | @var{key}, that's the end; the minibuffer is entered immediately to | |
1469 | read @var{cmd}. But if you type @kbd{C-x}, another character is read; | |
1470 | if that is @kbd{4}, another character is read, and so on. For | |
1471 | example, | |
1472 | ||
1473 | @example | |
1474 | M-x global-set-key @key{RET} C-x 4 $ spell-other-window @key{RET} | |
1475 | @end example | |
1476 | ||
1477 | @noindent | |
1478 | redefines @kbd{C-x 4 $} to run the (fictitious) command | |
1479 | @code{spell-other-window}. | |
1480 | ||
1481 | The two-character keys consisting of @kbd{C-c} followed by a letter | |
1482 | are reserved for user customizations. Lisp programs are not supposed to | |
1483 | define these keys, so the bindings you make for them will be available | |
1484 | in all major modes and will never get in the way of anything. | |
1485 | ||
1486 | You can remove the global definition of a key with | |
1487 | @code{global-unset-key}. This makes the key @dfn{undefined}; if you | |
1488 | type it, Emacs will just beep. Similarly, @code{local-unset-key} makes | |
1489 | a key undefined in the current major mode keymap, which makes the global | |
1490 | definition (or lack of one) come back into effect in that major mode. | |
1491 | ||
1492 | If you have redefined (or undefined) a key and you subsequently wish | |
1493 | to retract the change, undefining the key will not do the job---you need | |
1494 | to redefine the key with its standard definition. To find the name of | |
1495 | the standard definition of a key, go to a Fundamental mode buffer and | |
1496 | use @kbd{C-h c}. The documentation of keys in this manual also lists | |
1497 | their command names. | |
1498 | ||
1499 | If you want to prevent yourself from invoking a command by mistake, it | |
1500 | is better to disable the command than to undefine the key. A disabled | |
1501 | command is less work to invoke when you really want to. | |
1502 | @xref{Disabling}. | |
1503 | ||
1504 | @node Init Rebinding | |
1505 | @subsection Rebinding Keys in Your Init File | |
1506 | ||
6bf7aab6 DL |
1507 | If you have a set of key bindings that you like to use all the time, |
1508 | you can specify them in your @file{.emacs} file by using their Lisp | |
4ea68fcc | 1509 | syntax. (@xref{Init File}.) |
6bf7aab6 | 1510 | |
76dd3692 EZ |
1511 | The simplest method for doing this works for @acronym{ASCII} characters and |
1512 | Meta-modified @acronym{ASCII} characters only. This method uses a string to | |
6bf7aab6 DL |
1513 | represent the key sequence you want to rebind. For example, here's how |
1514 | to bind @kbd{C-z} to @code{shell}: | |
1515 | ||
1516 | @example | |
1517 | (global-set-key "\C-z" 'shell) | |
1518 | @end example | |
1519 | ||
1520 | @noindent | |
af1b4255 RS |
1521 | This example uses a string constant containing one character, |
1522 | @kbd{C-z}. (@samp{\C-} is string syntax for a control character.) The | |
1523 | single-quote before the command name, @code{shell}, marks it as a | |
6bf7aab6 DL |
1524 | constant symbol rather than a variable. If you omit the quote, Emacs |
1525 | would try to evaluate @code{shell} immediately as a variable. This | |
1526 | probably causes an error; it certainly isn't what you want. | |
1527 | ||
af1b4255 | 1528 | Here is another example that binds the key sequence @kbd{C-x M-l}: |
6bf7aab6 DL |
1529 | |
1530 | @example | |
af1b4255 | 1531 | (global-set-key "\C-x\M-l" 'make-symbolic-link) |
03d48361 RS |
1532 | @end example |
1533 | ||
1534 | To put @key{TAB}, @key{RET}, @key{ESC}, or @key{DEL} in the | |
1535 | string, you can use the Emacs Lisp escape sequences, @samp{\t}, | |
1536 | @samp{\r}, @samp{\e}, and @samp{\d}. Here is an example which binds | |
1537 | @kbd{C-x @key{TAB}}: | |
1538 | ||
1539 | @example | |
1540 | (global-set-key "\C-x\t" 'indent-rigidly) | |
ce3bd809 RS |
1541 | @end example |
1542 | ||
76dd3692 | 1543 | These examples show how to write some other special @acronym{ASCII} characters |
ce3bd809 RS |
1544 | in strings for key bindings: |
1545 | ||
1546 | @example | |
1547 | (global-set-key "\r" 'newline) ;; @key{RET} | |
1548 | (global-set-key "\d" 'delete-backward-char) ;; @key{DEL} | |
1549 | (global-set-key "\C-x\e\e" 'repeat-complex-command) ;; @key{ESC} | |
6bf7aab6 DL |
1550 | @end example |
1551 | ||
1552 | When the key sequence includes function keys or mouse button events, | |
76dd3692 | 1553 | or non-@acronym{ASCII} characters such as @code{C-=} or @code{H-a}, you must use |
6bf7aab6 DL |
1554 | the more general method of rebinding, which uses a vector to specify the |
1555 | key sequence. | |
1556 | ||
1557 | The way to write a vector in Emacs Lisp is with square brackets around | |
1558 | the vector elements. Use spaces to separate the elements. If an | |
1559 | element is a symbol, simply write the symbol's name---no other | |
1560 | delimiters or punctuation are needed. If a vector element is a | |
1561 | character, write it as a Lisp character constant: @samp{?} followed by | |
1562 | the character as it would appear in a string. | |
1563 | ||
1564 | Here are examples of using vectors to rebind @kbd{C-=} (a control | |
76dd3692 EZ |
1565 | character not in @acronym{ASCII}), @kbd{C-M-=} (not in @acronym{ASCII} because @kbd{C-=} |
1566 | is not), @kbd{H-a} (a Hyper character; @acronym{ASCII} doesn't have Hyper at | |
17ec59da | 1567 | all), @key{F7} (a function key), and @kbd{C-Mouse-1} (a |
6bf7aab6 DL |
1568 | keyboard-modified mouse button): |
1569 | ||
1570 | @example | |
1571 | (global-set-key [?\C-=] 'make-symbolic-link) | |
17ec59da | 1572 | (global-set-key [?\M-\C-=] 'make-symbolic-link) |
6bf7aab6 DL |
1573 | (global-set-key [?\H-a] 'make-symbolic-link) |
1574 | (global-set-key [f7] 'make-symbolic-link) | |
1575 | (global-set-key [C-mouse-1] 'make-symbolic-link) | |
1576 | @end example | |
1577 | ||
ce3bd809 | 1578 | You can use a vector for the simple cases too. Here's how to |
af1b4255 | 1579 | rewrite the first six examples above to use vectors: |
6bf7aab6 DL |
1580 | |
1581 | @example | |
1582 | (global-set-key [?\C-z] 'shell) | |
6bf7aab6 | 1583 | (global-set-key [?\C-x ?l] 'make-symbolic-link) |
03d48361 | 1584 | (global-set-key [?\C-x ?\t] 'indent-rigidly) |
ce3bd809 RS |
1585 | (global-set-key [?\r] 'newline) |
1586 | (global-set-key [?\d] 'delete-backward-char) | |
1587 | (global-set-key [?\C-x ?\e ?\e] 'repeat-complex-command) | |
6bf7aab6 DL |
1588 | @end example |
1589 | ||
ce3bd809 RS |
1590 | @noindent |
1591 | As you see, you represent a multi-character key sequence with a vector | |
af1b4255 | 1592 | by listing all of the characters in order within the square brackets that |
ce3bd809 RS |
1593 | delimit the vector. |
1594 | ||
8e082ecc | 1595 | Language and coding systems can cause problems with key bindings |
76dd3692 | 1596 | for non-@acronym{ASCII} characters. @xref{Non-ASCII Rebinding}. |
94720bc7 | 1597 | |
6bf7aab6 DL |
1598 | @node Function Keys |
1599 | @subsection Rebinding Function Keys | |
1600 | ||
1601 | Key sequences can contain function keys as well as ordinary | |
1602 | characters. Just as Lisp characters (actually integers) represent | |
1603 | keyboard characters, Lisp symbols represent function keys. If the | |
1604 | function key has a word as its label, then that word is also the name of | |
1605 | the corresponding Lisp symbol. Here are the conventional Lisp names for | |
1606 | common function keys: | |
1607 | ||
1608 | @table @asis | |
1609 | @item @code{left}, @code{up}, @code{right}, @code{down} | |
1610 | Cursor arrow keys. | |
1611 | ||
1612 | @item @code{begin}, @code{end}, @code{home}, @code{next}, @code{prior} | |
1613 | Other cursor repositioning keys. | |
1614 | ||
1615 | @item @code{select}, @code{print}, @code{execute}, @code{backtab} | |
1616 | @itemx @code{insert}, @code{undo}, @code{redo}, @code{clearline} | |
6b46232e | 1617 | @itemx @code{insertline}, @code{deleteline}, @code{insertchar}, @code{deletechar} |
6bf7aab6 DL |
1618 | Miscellaneous function keys. |
1619 | ||
1620 | @item @code{f1}, @code{f2}, @dots{} @code{f35} | |
1621 | Numbered function keys (across the top of the keyboard). | |
1622 | ||
1623 | @item @code{kp-add}, @code{kp-subtract}, @code{kp-multiply}, @code{kp-divide} | |
1624 | @itemx @code{kp-backtab}, @code{kp-space}, @code{kp-tab}, @code{kp-enter} | |
1625 | @itemx @code{kp-separator}, @code{kp-decimal}, @code{kp-equal} | |
1626 | Keypad keys (to the right of the regular keyboard), with names or punctuation. | |
1627 | ||
1628 | @item @code{kp-0}, @code{kp-1}, @dots{} @code{kp-9} | |
1629 | Keypad keys with digits. | |
1630 | ||
1631 | @item @code{kp-f1}, @code{kp-f2}, @code{kp-f3}, @code{kp-f4} | |
1632 | Keypad PF keys. | |
1633 | @end table | |
1634 | ||
1635 | These names are conventional, but some systems (especially when using | |
97878c08 EZ |
1636 | X) may use different names. To make certain what symbol is used for a |
1637 | given function key on your terminal, type @kbd{C-h c} followed by that | |
1638 | key. | |
6bf7aab6 DL |
1639 | |
1640 | A key sequence which contains function key symbols (or anything but | |
af1b4255 RS |
1641 | @acronym{ASCII} characters) must be a vector rather than a string. |
1642 | Thus, to bind function key @samp{f1} to the command @code{rmail}, | |
1643 | write the following: | |
6bf7aab6 DL |
1644 | |
1645 | @example | |
1646 | (global-set-key [f1] 'rmail) | |
1647 | @end example | |
1648 | ||
1649 | @noindent | |
1650 | To bind the right-arrow key to the command @code{forward-char}, you can | |
1651 | use this expression: | |
1652 | ||
1653 | @example | |
1654 | (global-set-key [right] 'forward-char) | |
1655 | @end example | |
1656 | ||
1657 | @noindent | |
1658 | This uses the Lisp syntax for a vector containing the symbol | |
1659 | @code{right}. (This binding is present in Emacs by default.) | |
1660 | ||
1661 | @xref{Init Rebinding}, for more information about using vectors for | |
1662 | rebinding. | |
1663 | ||
1664 | You can mix function keys and characters in a key sequence. This | |
1665 | example binds @kbd{C-x @key{NEXT}} to the command @code{forward-page}. | |
1666 | ||
1667 | @example | |
1668 | (global-set-key [?\C-x next] 'forward-page) | |
1669 | @end example | |
1670 | ||
1671 | @noindent | |
1672 | where @code{?\C-x} is the Lisp character constant for the character | |
1673 | @kbd{C-x}. The vector element @code{next} is a symbol and therefore | |
1674 | does not take a question mark. | |
1675 | ||
1676 | You can use the modifier keys @key{CTRL}, @key{META}, @key{HYPER}, | |
1677 | @key{SUPER}, @key{ALT} and @key{SHIFT} with function keys. To represent | |
1678 | these modifiers, add the strings @samp{C-}, @samp{M-}, @samp{H-}, | |
1679 | @samp{s-}, @samp{A-} and @samp{S-} at the front of the symbol name. | |
1680 | Thus, here is how to make @kbd{Hyper-Meta-@key{RIGHT}} move forward a | |
1681 | word: | |
1682 | ||
1683 | @example | |
1684 | (global-set-key [H-M-right] 'forward-word) | |
1685 | @end example | |
1686 | ||
617f06a8 RS |
1687 | @cindex keypad |
1688 | Many keyboards have a ``numeric keypad'' on the right hand side. | |
1689 | The numeric keys in the keypad double up as cursor motion keys, | |
1690 | toggled by a key labelled @samp{Num Lock}. By default, Emacs | |
c04a2eab RS |
1691 | translates these keys to the corresponding keys in the main keyboard. |
1692 | For example, when @samp{Num Lock} is on, the key labelled @samp{8} on | |
1693 | the numeric keypad produces @code{kp-8}, which is translated to | |
1694 | @kbd{8}; when @samp{Num Lock} is off, the same key produces | |
1695 | @code{kp-up}, which is translated to @key{UP}. If you rebind a key | |
1696 | such as @kbd{8} or @key{UP}, it affects the equivalent keypad key too. | |
1697 | However, if you rebind a @samp{kp-} key directly, that won't affect | |
1698 | its non-keypad equivalent. | |
617f06a8 RS |
1699 | |
1700 | Emacs provides a convenient method for binding the numeric keypad | |
1701 | keys, using the variables @code{keypad-setup}, | |
1702 | @code{keypad-numlock-setup}, @code{keypad-shifted-setup}, and | |
1703 | @code{keypad-numlock-shifted-setup}. These can be found in the | |
1704 | @samp{keyboard} customization group (@pxref{Easy Customization}). You | |
1705 | can rebind the keys to perform other tasks, such as issuing numeric | |
1706 | prefix arguments. | |
1707 | ||
6bf7aab6 | 1708 | @node Named ASCII Chars |
76dd3692 | 1709 | @subsection Named @acronym{ASCII} Control Characters |
6bf7aab6 DL |
1710 | |
1711 | @key{TAB}, @key{RET}, @key{BS}, @key{LFD}, @key{ESC} and @key{DEL} | |
af1b4255 RS |
1712 | started out as names for certain @acronym{ASCII} control characters, |
1713 | used so often that they have special keys of their own. For instance, | |
1714 | @key{TAB} was another name for @kbd{C-i}. Later, users found it | |
6bf7aab6 | 1715 | convenient to distinguish in Emacs between these keys and the ``same'' |
af1b4255 RS |
1716 | control characters typed with the @key{CTRL} key. Therefore, on most |
1717 | modern terminals, they are no longer the same, and @key{TAB} is | |
1718 | distinguishable from @kbd{C-i}. | |
1719 | ||
1720 | Emacs can distinguish these two kinds of input if the keyboard does. | |
1721 | It treats the ``special'' keys as function keys named @code{tab}, | |
1722 | @code{return}, @code{backspace}, @code{linefeed}, @code{escape}, and | |
1723 | @code{delete}. These function keys translate automatically into the | |
1724 | corresponding @acronym{ASCII} characters @emph{if} they have no | |
1725 | bindings of their own. As a result, neither users nor Lisp programs | |
1726 | need to pay attention to the distinction unless they care to. | |
6bf7aab6 DL |
1727 | |
1728 | If you do not want to distinguish between (for example) @key{TAB} and | |
76dd3692 | 1729 | @kbd{C-i}, make just one binding, for the @acronym{ASCII} character @key{TAB} |
6bf7aab6 | 1730 | (octal code 011). If you do want to distinguish, make one binding for |
76dd3692 | 1731 | this @acronym{ASCII} character, and another for the ``function key'' @code{tab}. |
6bf7aab6 | 1732 | |
76dd3692 | 1733 | With an ordinary @acronym{ASCII} terminal, there is no way to distinguish |
6bf7aab6 DL |
1734 | between @key{TAB} and @kbd{C-i} (and likewise for other such pairs), |
1735 | because the terminal sends the same character in both cases. | |
1736 | ||
1737 | @node Non-ASCII Rebinding | |
76dd3692 EZ |
1738 | @subsection Non-@acronym{ASCII} Characters on the Keyboard |
1739 | @cindex rebinding non-@acronym{ASCII} keys | |
1740 | @cindex non-@acronym{ASCII} keys, binding | |
6bf7aab6 | 1741 | |
6f368e2d RS |
1742 | If your keyboard has keys that send non-@acronym{ASCII} |
1743 | characters, such as accented letters, rebinding these keys | |
1744 | must be done by using a vector like this@footnote{Note that | |
1745 | you should avoid the string syntax for binding | |
1746 | non-@acronym{ASCII} characters, since they will be | |
1747 | interpreted as meta keys. @xref{Strings of Events,,,elisp, | |
1748 | The Emacs Lisp Reference Manual}.}: | |
6bf7aab6 DL |
1749 | |
1750 | @example | |
1751 | (global-set-key [?@var{char}] 'some-function) | |
1752 | @end example | |
1753 | ||
1754 | @noindent | |
6a9a44bf | 1755 | Type @kbd{C-q} followed by the key you want to bind, to insert @var{char}. |
6bf7aab6 | 1756 | |
6f368e2d | 1757 | Since this puts a non-@acronym{ASCII} character in the @file{.emacs}, |
2038519d RS |
1758 | you should specify a coding system for that file that supports the |
1759 | character in question. @xref{Init Syntax}. | |
1760 | ||
1761 | @strong{Warning:} if you change the keyboard encoding, or change | |
1762 | between multibyte and unibyte mode, or anything that would alter which | |
1763 | code @kbd{C-q} would insert for that character, you'll need to edit | |
1764 | the Lisp expression accordingly, to use the character code generated | |
1765 | by @kbd{C-q} in the new mode. | |
0a7790e0 | 1766 | |
6bf7aab6 DL |
1767 | @node Mouse Buttons |
1768 | @subsection Rebinding Mouse Buttons | |
1769 | @cindex mouse button events | |
1770 | @cindex rebinding mouse buttons | |
1771 | @cindex click events | |
1772 | @cindex drag events | |
1773 | @cindex down events | |
1774 | @cindex button down events | |
1775 | ||
1776 | Emacs uses Lisp symbols to designate mouse buttons, too. The ordinary | |
1777 | mouse events in Emacs are @dfn{click} events; these happen when you | |
1778 | press a button and release it without moving the mouse. You can also | |
1779 | get @dfn{drag} events, when you move the mouse while holding the button | |
1780 | down. Drag events happen when you finally let go of the button. | |
1781 | ||
1782 | The symbols for basic click events are @code{mouse-1} for the leftmost | |
1783 | button, @code{mouse-2} for the next, and so on. Here is how you can | |
1784 | redefine the second mouse button to split the current window: | |
1785 | ||
1786 | @example | |
1787 | (global-set-key [mouse-2] 'split-window-vertically) | |
1788 | @end example | |
1789 | ||
1790 | The symbols for drag events are similar, but have the prefix | |
1791 | @samp{drag-} before the word @samp{mouse}. For example, dragging the | |
1792 | first button generates a @code{drag-mouse-1} event. | |
1793 | ||
1794 | You can also define bindings for events that occur when a mouse button | |
1795 | is pressed down. These events start with @samp{down-} instead of | |
1796 | @samp{drag-}. Such events are generated only if they have key bindings. | |
1797 | When you get a button-down event, a corresponding click or drag event | |
1798 | will always follow. | |
1799 | ||
1800 | @cindex double clicks | |
1801 | @cindex triple clicks | |
1802 | If you wish, you can distinguish single, double, and triple clicks. A | |
1803 | double click means clicking a mouse button twice in approximately the | |
1804 | same place. The first click generates an ordinary click event. The | |
1805 | second click, if it comes soon enough, generates a double-click event | |
1806 | instead. The event type for a double-click event starts with | |
1807 | @samp{double-}: for example, @code{double-mouse-3}. | |
1808 | ||
1809 | This means that you can give a special meaning to the second click at | |
1810 | the same place, but it must act on the assumption that the ordinary | |
1811 | single click definition has run when the first click was received. | |
1812 | ||
1813 | This constrains what you can do with double clicks, but user interface | |
1814 | designers say that this constraint ought to be followed in any case. A | |
1815 | double click should do something similar to the single click, only | |
1816 | ``more so.'' The command for the double-click event should perform the | |
1817 | extra work for the double click. | |
1818 | ||
1819 | If a double-click event has no binding, it changes to the | |
1820 | corresponding single-click event. Thus, if you don't define a | |
1821 | particular double click specially, it executes the single-click command | |
1822 | twice. | |
1823 | ||
1824 | Emacs also supports triple-click events whose names start with | |
1825 | @samp{triple-}. Emacs does not distinguish quadruple clicks as event | |
1826 | types; clicks beyond the third generate additional triple-click events. | |
1827 | However, the full number of clicks is recorded in the event list, so you | |
1828 | can distinguish if you really want to. We don't recommend distinct | |
1829 | meanings for more than three clicks, but sometimes it is useful for | |
1830 | subsequent clicks to cycle through the same set of three meanings, so | |
1831 | that four clicks are equivalent to one click, five are equivalent to | |
1832 | two, and six are equivalent to three. | |
1833 | ||
1834 | Emacs also records multiple presses in drag and button-down events. | |
1835 | For example, when you press a button twice, then move the mouse while | |
1836 | holding the button, Emacs gets a @samp{double-drag-} event. And at the | |
1837 | moment when you press it down for the second time, Emacs gets a | |
1838 | @samp{double-down-} event (which is ignored, like all button-down | |
1839 | events, if it has no binding). | |
1840 | ||
1841 | @vindex double-click-time | |
17ec59da RS |
1842 | The variable @code{double-click-time} specifies how much time can |
1843 | elapse between clicks and still allow them to be grouped as a multiple | |
1844 | click. Its value is in units of milliseconds. If the value is | |
1845 | @code{nil}, double clicks are not detected at all. If the value is | |
4dfff41f | 1846 | @code{t}, then there is no time limit. The default is 500. |
6bf7aab6 | 1847 | |
4e8864c7 GM |
1848 | @vindex double-click-fuzz |
1849 | The variable @code{double-click-fuzz} specifies how much the mouse | |
17ec59da | 1850 | can move between clicks still allow them to be grouped as a multiple |
03812848 EZ |
1851 | click. Its value is in units of pixels on windowed displays and in |
1852 | units of 1/8 of a character cell on text-mode terminals; the default is | |
1853 | 3. | |
4e8864c7 | 1854 | |
6bf7aab6 DL |
1855 | The symbols for mouse events also indicate the status of the modifier |
1856 | keys, with the usual prefixes @samp{C-}, @samp{M-}, @samp{H-}, | |
1857 | @samp{s-}, @samp{A-} and @samp{S-}. These always precede @samp{double-} | |
1858 | or @samp{triple-}, which always precede @samp{drag-} or @samp{down-}. | |
1859 | ||
1860 | A frame includes areas that don't show text from the buffer, such as | |
1861 | the mode line and the scroll bar. You can tell whether a mouse button | |
1862 | comes from a special area of the screen by means of dummy ``prefix | |
1863 | keys.'' For example, if you click the mouse in the mode line, you get | |
1864 | the prefix key @code{mode-line} before the ordinary mouse-button symbol. | |
1865 | Thus, here is how to define the command for clicking the first button in | |
1866 | a mode line to run @code{scroll-up}: | |
1867 | ||
1868 | @example | |
1869 | (global-set-key [mode-line mouse-1] 'scroll-up) | |
1870 | @end example | |
1871 | ||
1872 | Here is the complete list of these dummy prefix keys and their | |
1873 | meanings: | |
1874 | ||
1875 | @table @code | |
1876 | @item mode-line | |
1877 | The mouse was in the mode line of a window. | |
1878 | @item vertical-line | |
1879 | The mouse was in the vertical line separating side-by-side windows. (If | |
1880 | you use scroll bars, they appear in place of these vertical lines.) | |
1881 | @item vertical-scroll-bar | |
1882 | The mouse was in a vertical scroll bar. (This is the only kind of | |
1883 | scroll bar Emacs currently supports.) | |
1884 | @ignore | |
1885 | @item horizontal-scroll-bar | |
1886 | The mouse was in a horizontal scroll bar. Horizontal scroll bars do | |
1887 | horizontal scrolling, and people don't use them often. | |
1888 | @end ignore | |
1889 | @end table | |
1890 | ||
1891 | You can put more than one mouse button in a key sequence, but it isn't | |
1892 | usual to do so. | |
1893 | ||
1894 | @node Disabling | |
1895 | @subsection Disabling Commands | |
1896 | @cindex disabled command | |
1897 | ||
1898 | Disabling a command marks the command as requiring confirmation before it | |
1899 | can be executed. The purpose of disabling a command is to prevent | |
1900 | beginning users from executing it by accident and being confused. | |
1901 | ||
1902 | An attempt to invoke a disabled command interactively in Emacs | |
1903 | displays a window containing the command's name, its documentation, and | |
1904 | some instructions on what to do immediately; then Emacs asks for input | |
1905 | saying whether to execute the command as requested, enable it and | |
1906 | execute it, or cancel. If you decide to enable the command, you are | |
1907 | asked whether to do this permanently or just for the current session. | |
6b46232e RS |
1908 | (Enabling permanently works by automatically editing your @file{.emacs} |
1909 | file.) You can also type @kbd{!} to enable @emph{all} commands, | |
1910 | for the current session only. | |
6bf7aab6 DL |
1911 | |
1912 | The direct mechanism for disabling a command is to put a | |
1913 | non-@code{nil} @code{disabled} property on the Lisp symbol for the | |
1914 | command. Here is the Lisp program to do this: | |
1915 | ||
1916 | @example | |
1917 | (put 'delete-region 'disabled t) | |
1918 | @end example | |
1919 | ||
1920 | If the value of the @code{disabled} property is a string, that string | |
1ba2ce68 | 1921 | is included in the message displayed when the command is used: |
6bf7aab6 DL |
1922 | |
1923 | @example | |
1924 | (put 'delete-region 'disabled | |
1925 | "It's better to use `kill-region' instead.\n") | |
1926 | @end example | |
1927 | ||
1928 | @findex disable-command | |
1929 | @findex enable-command | |
1930 | You can make a command disabled either by editing the @file{.emacs} | |
1931 | file directly or with the command @kbd{M-x disable-command}, which edits | |
1932 | the @file{.emacs} file for you. Likewise, @kbd{M-x enable-command} | |
1933 | edits @file{.emacs} to enable a command permanently. @xref{Init File}. | |
33b0dcb8 EZ |
1934 | |
1935 | If Emacs was invoked with the @option{-q} or @option{--no-init-file} | |
1936 | options (@pxref{Initial Options}), it will not edit your | |
1937 | @file{~/.emacs} init file. This is because editing the init file from | |
1938 | such a session might overwrite the lines you might have on your init | |
1939 | file which enable and disable commands. | |
6bf7aab6 DL |
1940 | |
1941 | Whether a command is disabled is independent of what key is used to | |
1942 | invoke it; disabling also applies if the command is invoked using | |
1943 | @kbd{M-x}. Disabling a command has no effect on calling it as a | |
1944 | function from Lisp programs. | |
1945 | ||
6bf7aab6 DL |
1946 | @node Syntax |
1947 | @section The Syntax Table | |
1948 | @cindex syntax table | |
1949 | ||
1950 | All the Emacs commands which parse words or balance parentheses are | |
1951 | controlled by the @dfn{syntax table}. The syntax table says which | |
1952 | characters are opening delimiters, which are parts of words, which are | |
dc08c4a0 RS |
1953 | string quotes, and so on. It does this by assigning each character to |
1954 | one of fifteen-odd @dfn{syntax classes}. In some cases it specifies | |
1955 | some additional information also. | |
1956 | ||
b2d77e08 RS |
1957 | Each major mode has its own syntax table (though related major modes |
1958 | sometimes share one syntax table) which it installs in each buffer | |
dc08c4a0 RS |
1959 | that uses the mode. The syntax table installed in the current buffer |
1960 | is the one that all commands use, so we call it ``the'' syntax table. | |
6bf7aab6 DL |
1961 | |
1962 | @kindex C-h s | |
1963 | @findex describe-syntax | |
dc08c4a0 RS |
1964 | To display a description of the contents of the current syntax |
1965 | table, type @kbd{C-h s} (@code{describe-syntax}). The description of | |
1966 | each character includes both the string you would have to give to | |
6bf7aab6 | 1967 | @code{modify-syntax-entry} to set up that character's current syntax, |
dc08c4a0 RS |
1968 | starting with the character which designates its syntax class, plus |
1969 | some English text to explain its meaning. | |
6bf7aab6 | 1970 | |
dc08c4a0 RS |
1971 | A syntax table is actually a Lisp object, a char-table, whose |
1972 | elements are cons cells. For full information on the syntax table, | |
1973 | see @ref{Syntax Tables,, Syntax Tables, elisp, The Emacs Lisp | |
1974 | Reference Manual}. | |
6bf7aab6 DL |
1975 | |
1976 | @node Init File | |
1977 | @section The Init File, @file{~/.emacs} | |
1978 | @cindex init file | |
1979 | @cindex Emacs initialization file | |
1980 | @cindex key rebinding, permanent | |
1981 | @cindex rebinding keys, permanently | |
1982 | @cindex startup (init file) | |
1983 | ||
af1b4255 RS |
1984 | When Emacs is started, it normally loads a Lisp program from the |
1985 | file @file{.emacs} or @file{.emacs.el} in your home directory. (You | |
1986 | can also put it in a subdirectory @file{~/.emacs.d} and Emacs will | |
1987 | still find it.) We call this file your @dfn{init file} because it | |
1988 | specifies how to initialize Emacs for you. You can use the command | |
1989 | line switch @samp{-q} to prevent loading your init file, and @samp{-u} | |
1990 | (or @samp{--user}) to specify a different user's init file | |
1991 | (@pxref{Initial Options}). | |
6bf7aab6 | 1992 | |
14a893ee | 1993 | @cindex @file{default.el}, the default init file |
6bf7aab6 DL |
1994 | There can also be a @dfn{default init file}, which is the library |
1995 | named @file{default.el}, found via the standard search path for | |
1996 | libraries. The Emacs distribution contains no such library; your site | |
1997 | may create one for local customizations. If this library exists, it is | |
1998 | loaded whenever you start Emacs (except when you specify @samp{-q}). | |
1999 | But your init file, if any, is loaded first; if it sets | |
2000 | @code{inhibit-default-init} non-@code{nil}, then @file{default} is not | |
2001 | loaded. | |
2002 | ||
14a893ee EZ |
2003 | @cindex site init file |
2004 | @cindex @file{site-start.el}, the site startup file | |
6bf7aab6 | 2005 | Your site may also have a @dfn{site startup file}; this is named |
14a893ee EZ |
2006 | @file{site-start.el}, if it exists. Like @file{default.el}, Emacs |
2007 | finds this file via the standard search path for Lisp libraries. | |
2008 | Emacs loads this library before it loads your init file. To inhibit | |
25efa2de | 2009 | loading of this library, use the option @samp{--no-site-file}. |
14a893ee EZ |
2010 | @xref{Initial Options}. |
2011 | ||
2012 | You can place @file{default.el} and @file{site-start.el} in any of | |
2013 | the directories which Emacs searches for Lisp libraries. The variable | |
2014 | @code{load-path} (@pxref{Lisp Libraries}) specifies these directories. | |
2015 | Many sites put these files in the @file{site-lisp} subdirectory of the | |
2016 | Emacs installation directory, typically | |
2017 | @file{/usr/local/share/emacs/site-lisp}. | |
6bf7aab6 DL |
2018 | |
2019 | If you have a large amount of code in your @file{.emacs} file, you | |
2020 | should rename it to @file{~/.emacs.el}, and byte-compile it. @xref{Byte | |
2021 | Compilation,, Byte Compilation, elisp, the Emacs Lisp Reference Manual}, | |
2022 | for more information about compiling Emacs Lisp programs. | |
2023 | ||
2024 | If you are going to write actual Emacs Lisp programs that go beyond | |
2025 | minor customization, you should read the @cite{Emacs Lisp Reference Manual}. | |
2026 | @ifinfo | |
2027 | @xref{Top, Emacs Lisp, Emacs Lisp, elisp, the Emacs Lisp Reference | |
2028 | Manual}. | |
2029 | @end ifinfo | |
2030 | ||
2031 | @menu | |
2032 | * Init Syntax:: Syntax of constants in Emacs Lisp. | |
2033 | * Init Examples:: How to do some things with an init file. | |
2034 | * Terminal Init:: Each terminal type can have an init file. | |
2035 | * Find Init:: How Emacs finds the init file. | |
2036 | @end menu | |
2037 | ||
2038 | @node Init Syntax | |
2039 | @subsection Init File Syntax | |
2040 | ||
2041 | The @file{.emacs} file contains one or more Lisp function call | |
2042 | expressions. Each of these consists of a function name followed by | |
2043 | arguments, all surrounded by parentheses. For example, @code{(setq | |
2044 | fill-column 60)} calls the function @code{setq} to set the variable | |
2045 | @code{fill-column} (@pxref{Filling}) to 60. | |
2046 | ||
a67091f2 RS |
2047 | You can set any Lisp variable with @code{setq}, but with certain |
2048 | variables @code{setq} won't do what you probably want in the | |
2049 | @file{.emacs} file. Some variables automatically become buffer-local | |
2050 | when set with @code{setq}; what you want in @file{.emacs} is to set | |
2051 | the default value, using @code{setq-default}. Some customizable minor | |
2052 | mode variables do special things to enable the mode when you set them | |
2053 | with Customize, but ordinary @code{setq} won't do that; to enable the | |
2054 | mode in your @file{.emacs} file, call the minor mode command. The | |
2055 | following section has examples of both of these methods. | |
2056 | ||
2057 | The second argument to @code{setq} is an expression for the new | |
2058 | value of the variable. This can be a constant, a variable, or a | |
2059 | function call expression. In @file{.emacs}, constants are used most | |
2060 | of the time. They can be: | |
6bf7aab6 DL |
2061 | |
2062 | @table @asis | |
2063 | @item Numbers: | |
2064 | Numbers are written in decimal, with an optional initial minus sign. | |
2065 | ||
2066 | @item Strings: | |
2067 | @cindex Lisp string syntax | |
2068 | @cindex string syntax | |
2069 | Lisp string syntax is the same as C string syntax with a few extra | |
2070 | features. Use a double-quote character to begin and end a string constant. | |
2071 | ||
2072 | In a string, you can include newlines and special characters literally. | |
2073 | But often it is cleaner to use backslash sequences for them: @samp{\n} | |
2074 | for newline, @samp{\b} for backspace, @samp{\r} for carriage return, | |
2075 | @samp{\t} for tab, @samp{\f} for formfeed (control-L), @samp{\e} for | |
2076 | escape, @samp{\\} for a backslash, @samp{\"} for a double-quote, or | |
2077 | @samp{\@var{ooo}} for the character whose octal code is @var{ooo}. | |
2078 | Backslash and double-quote are the only characters for which backslash | |
2079 | sequences are mandatory. | |
2080 | ||
2081 | @samp{\C-} can be used as a prefix for a control character, as in | |
76dd3692 | 2082 | @samp{\C-s} for @acronym{ASCII} control-S, and @samp{\M-} can be used as a prefix for |
6bf7aab6 DL |
2083 | a Meta character, as in @samp{\M-a} for @kbd{Meta-A} or @samp{\M-\C-a} for |
2084 | @kbd{Control-Meta-A}.@refill | |
2085 | ||
e2bf12ba | 2086 | @cindex international characters in @file{.emacs} |
76dd3692 EZ |
2087 | @cindex non-@acronym{ASCII} characters in @file{.emacs} |
2088 | If you want to include non-@acronym{ASCII} characters in strings in your init | |
bbde4442 EZ |
2089 | file, you should consider putting a @w{@samp{-*-coding: |
2090 | @var{coding-system}-*-}} tag on the first line which states the coding | |
2ab9e3ce | 2091 | system used to save your @file{.emacs}, as explained in @ref{Recognize |
76dd3692 | 2092 | Coding}. This is because the defaults for decoding non-@acronym{ASCII} text might |
2ab9e3ce EZ |
2093 | not yet be set up by the time Emacs reads those parts of your init file |
2094 | which use such strings, possibly leading Emacs to decode those strings | |
2095 | incorrectly. | |
e2bf12ba | 2096 | |
6bf7aab6 DL |
2097 | @item Characters: |
2098 | Lisp character constant syntax consists of a @samp{?} followed by | |
2099 | either a character or an escape sequence starting with @samp{\}. | |
2100 | Examples: @code{?x}, @code{?\n}, @code{?\"}, @code{?\)}. Note that | |
2101 | strings and characters are not interchangeable in Lisp; some contexts | |
2102 | require one and some contexts require the other. | |
2103 | ||
bbde4442 | 2104 | @xref{Non-ASCII Rebinding}, for information about binding commands to |
76dd3692 | 2105 | keys which send non-@acronym{ASCII} characters. |
bbde4442 | 2106 | |
6bf7aab6 DL |
2107 | @item True: |
2108 | @code{t} stands for `true'. | |
2109 | ||
2110 | @item False: | |
2111 | @code{nil} stands for `false'. | |
2112 | ||
2113 | @item Other Lisp objects: | |
acead980 | 2114 | Write a single-quote (@code{'}) followed by the Lisp object you want. |
6bf7aab6 DL |
2115 | @end table |
2116 | ||
2117 | @node Init Examples | |
2118 | @subsection Init File Examples | |
2119 | ||
2120 | Here are some examples of doing certain commonly desired things with | |
2121 | Lisp expressions: | |
2122 | ||
2123 | @itemize @bullet | |
2124 | @item | |
2125 | Make @key{TAB} in C mode just insert a tab if point is in the middle of a | |
2126 | line. | |
2127 | ||
2128 | @example | |
2129 | (setq c-tab-always-indent nil) | |
2130 | @end example | |
2131 | ||
2132 | Here we have a variable whose value is normally @code{t} for `true' | |
2133 | and the alternative is @code{nil} for `false'. | |
2134 | ||
2135 | @item | |
2136 | Make searches case sensitive by default (in all buffers that do not | |
2137 | override this). | |
2138 | ||
2139 | @example | |
2140 | (setq-default case-fold-search nil) | |
2141 | @end example | |
2142 | ||
2143 | This sets the default value, which is effective in all buffers that do | |
2144 | not have local values for the variable. Setting @code{case-fold-search} | |
2145 | with @code{setq} affects only the current buffer's local value, which | |
2146 | is not what you probably want to do in an init file. | |
2147 | ||
2148 | @item | |
2149 | @vindex user-mail-address | |
2150 | Specify your own email address, if Emacs can't figure it out correctly. | |
2151 | ||
2152 | @example | |
2153 | (setq user-mail-address "coon@@yoyodyne.com") | |
2154 | @end example | |
2155 | ||
2156 | Various Emacs packages that need your own email address use the value of | |
2157 | @code{user-mail-address}. | |
2158 | ||
2159 | @item | |
2160 | Make Text mode the default mode for new buffers. | |
2161 | ||
2162 | @example | |
2163 | (setq default-major-mode 'text-mode) | |
2164 | @end example | |
2165 | ||
2166 | Note that @code{text-mode} is used because it is the command for | |
2167 | entering Text mode. The single-quote before it makes the symbol a | |
2168 | constant; otherwise, @code{text-mode} would be treated as a variable | |
2169 | name. | |
2170 | ||
2171 | @need 1500 | |
2172 | @item | |
2173 | Set up defaults for the Latin-1 character set | |
2174 | which supports most of the languages of Western Europe. | |
2175 | ||
2176 | @example | |
2177 | (set-language-environment "Latin-1") | |
2178 | @end example | |
2179 | ||
a67091f2 RS |
2180 | @need 1500 |
2181 | @item | |
2182 | Turn off Line Number mode, a global minor mode. | |
2183 | ||
2184 | @example | |
2185 | (line-number-mode 0) | |
2186 | @end example | |
2187 | ||
6bf7aab6 DL |
2188 | @need 1500 |
2189 | @item | |
2190 | Turn on Auto Fill mode automatically in Text mode and related modes. | |
2191 | ||
2192 | @example | |
2193 | (add-hook 'text-mode-hook | |
5d9dd378 | 2194 | '(lambda () (auto-fill-mode 1))) |
6bf7aab6 DL |
2195 | @end example |
2196 | ||
2197 | This shows how to add a hook function to a normal hook variable | |
2198 | (@pxref{Hooks}). The function we supply is a list starting with | |
2199 | @code{lambda}, with a single-quote in front of it to make it a list | |
2200 | constant rather than an expression. | |
2201 | ||
2202 | It's beyond the scope of this manual to explain Lisp functions, but for | |
2203 | this example it is enough to know that the effect is to execute | |
2204 | @code{(auto-fill-mode 1)} when Text mode is entered. You can replace | |
2205 | that with any other expression that you like, or with several | |
2206 | expressions in a row. | |
2207 | ||
2208 | Emacs comes with a function named @code{turn-on-auto-fill} whose | |
2209 | definition is @code{(lambda () (auto-fill-mode 1))}. Thus, a simpler | |
2210 | way to write the above example is as follows: | |
2211 | ||
2212 | @example | |
2213 | (add-hook 'text-mode-hook 'turn-on-auto-fill) | |
2214 | @end example | |
2215 | ||
2216 | @item | |
2217 | Load the installed Lisp library named @file{foo} (actually a file | |
2218 | @file{foo.elc} or @file{foo.el} in a standard Emacs directory). | |
2219 | ||
2220 | @example | |
2221 | (load "foo") | |
2222 | @end example | |
2223 | ||
2224 | When the argument to @code{load} is a relative file name, not starting | |
2225 | with @samp{/} or @samp{~}, @code{load} searches the directories in | |
2226 | @code{load-path} (@pxref{Lisp Libraries}). | |
2227 | ||
2228 | @item | |
2229 | Load the compiled Lisp file @file{foo.elc} from your home directory. | |
2230 | ||
2231 | @example | |
2232 | (load "~/foo.elc") | |
2233 | @end example | |
2234 | ||
2235 | Here an absolute file name is used, so no searching is done. | |
2236 | ||
bbde4442 EZ |
2237 | @item |
2238 | @cindex loading Lisp libraries automatically | |
2239 | @cindex autoload Lisp libraries | |
b2d77e08 RS |
2240 | Tell Emacs to find the definition for the function @code{myfunction} |
2241 | by loading a Lisp library named @file{mypackage} (i.e.@: a file | |
2242 | @file{mypackage.elc} or @file{mypackage.el}): | |
bbde4442 EZ |
2243 | |
2244 | @example | |
2245 | (autoload 'myfunction "mypackage" "Do what I say." t) | |
2246 | @end example | |
2247 | ||
2248 | @noindent | |
b2d77e08 RS |
2249 | Here the string @code{"Do what I say."} is the function's |
2250 | documentation string. You specify it in the @code{autoload} | |
2251 | definition so it will be available for help commands even when the | |
2252 | package is not loaded. The last argument, @code{t}, indicates that | |
2253 | this function is interactive; that is, it can be invoked interactively | |
2254 | by typing @kbd{M-x myfunction @key{RET}} or by binding it to a key. | |
2255 | If the function is not interactive, omit the @code{t} or use | |
2256 | @code{nil}. | |
bbde4442 | 2257 | |
6bf7aab6 | 2258 | @item |
af1b4255 | 2259 | Rebind the key @kbd{C-x l} to run the function @code{make-symbolic-link} |
3606516c | 2260 | (@pxref{Init Rebinding}). |
6bf7aab6 DL |
2261 | |
2262 | @example | |
2263 | (global-set-key "\C-xl" 'make-symbolic-link) | |
2264 | @end example | |
2265 | ||
2266 | or | |
2267 | ||
2268 | @example | |
2269 | (define-key global-map "\C-xl" 'make-symbolic-link) | |
2270 | @end example | |
2271 | ||
2272 | Note once again the single-quote used to refer to the symbol | |
2273 | @code{make-symbolic-link} instead of its value as a variable. | |
2274 | ||
2275 | @item | |
2276 | Do the same thing for Lisp mode only. | |
2277 | ||
2278 | @example | |
2279 | (define-key lisp-mode-map "\C-xl" 'make-symbolic-link) | |
2280 | @end example | |
2281 | ||
2282 | @item | |
2283 | Redefine all keys which now run @code{next-line} in Fundamental mode | |
2284 | so that they run @code{forward-line} instead. | |
2285 | ||
4ea68fcc | 2286 | @findex substitute-key-definition |
6bf7aab6 DL |
2287 | @example |
2288 | (substitute-key-definition 'next-line 'forward-line | |
2289 | global-map) | |
2290 | @end example | |
2291 | ||
2292 | @item | |
2293 | Make @kbd{C-x C-v} undefined. | |
2294 | ||
2295 | @example | |
2296 | (global-unset-key "\C-x\C-v") | |
2297 | @end example | |
2298 | ||
2299 | One reason to undefine a key is so that you can make it a prefix. | |
2300 | Simply defining @kbd{C-x C-v @var{anything}} will make @kbd{C-x C-v} a | |
2301 | prefix, but @kbd{C-x C-v} must first be freed of its usual non-prefix | |
2302 | definition. | |
2303 | ||
2304 | @item | |
2305 | Make @samp{$} have the syntax of punctuation in Text mode. | |
2306 | Note the use of a character constant for @samp{$}. | |
2307 | ||
2308 | @example | |
2309 | (modify-syntax-entry ?\$ "." text-mode-syntax-table) | |
2310 | @end example | |
2311 | ||
2312 | @item | |
2313 | Enable the use of the command @code{narrow-to-region} without confirmation. | |
2314 | ||
2315 | @example | |
2316 | (put 'narrow-to-region 'disabled nil) | |
2317 | @end example | |
1ac79b8b SM |
2318 | |
2319 | @item | |
2059927b | 2320 | Adjusting the configuration to various platforms and Emacs versions. |
1ac79b8b | 2321 | |
2059927b RS |
2322 | Users typically want Emacs to behave the same on all systems, so the |
2323 | same init file is right for all platforms. However, sometimes it | |
2324 | happens that a function you use for customizing Emacs is not available | |
2325 | on some platforms or in older Emacs versions. To deal with that | |
2326 | situation, put the customization inside a conditional that tests whether | |
2327 | the function or facility is available, like this: | |
1ac79b8b SM |
2328 | |
2329 | @example | |
2059927b RS |
2330 | (if (fboundp 'blink-cursor-mode) |
2331 | (blink-cursor-mode 0)) | |
1ac79b8b | 2332 | |
1ac79b8b | 2333 | (if (boundp 'coding-category-utf-8) |
2059927b | 2334 | (set-coding-priority '(coding-category-utf-8))) |
1ac79b8b SM |
2335 | @end example |
2336 | ||
2059927b RS |
2337 | @noindent |
2338 | You can also simply disregard the errors that occur if the | |
2339 | function is not defined. | |
2340 | ||
1ac79b8b | 2341 | @example |
2059927b RS |
2342 | (condition case () |
2343 | (set-face-background 'region "grey75") | |
2344 | (error nil)) | |
1ac79b8b SM |
2345 | @end example |
2346 | ||
2059927b RS |
2347 | A @code{setq} on a variable which does not exist is generally |
2348 | harmless, so those do not need a conditional. | |
6bf7aab6 DL |
2349 | @end itemize |
2350 | ||
2351 | @node Terminal Init | |
2352 | @subsection Terminal-specific Initialization | |
2353 | ||
2354 | Each terminal type can have a Lisp library to be loaded into Emacs when | |
2355 | it is run on that type of terminal. For a terminal type named | |
2356 | @var{termtype}, the library is called @file{term/@var{termtype}} and it is | |
2357 | found by searching the directories @code{load-path} as usual and trying the | |
2358 | suffixes @samp{.elc} and @samp{.el}. Normally it appears in the | |
2359 | subdirectory @file{term} of the directory where most Emacs libraries are | |
2360 | kept.@refill | |
2361 | ||
2362 | The usual purpose of the terminal-specific library is to map the | |
2363 | escape sequences used by the terminal's function keys onto more | |
2364 | meaningful names, using @code{function-key-map}. See the file | |
2365 | @file{term/lk201.el} for an example of how this is done. Many function | |
2366 | keys are mapped automatically according to the information in the | |
2367 | Termcap data base; the terminal-specific library needs to map only the | |
2368 | function keys that Termcap does not specify. | |
2369 | ||
2370 | When the terminal type contains a hyphen, only the part of the name | |
2371 | before the first hyphen is significant in choosing the library name. | |
2372 | Thus, terminal types @samp{aaa-48} and @samp{aaa-30-rv} both use | |
2373 | the library @file{term/aaa}. The code in the library can use | |
2374 | @code{(getenv "TERM")} to find the full terminal type name.@refill | |
2375 | ||
2376 | @vindex term-file-prefix | |
2377 | The library's name is constructed by concatenating the value of the | |
2378 | variable @code{term-file-prefix} and the terminal type. Your @file{.emacs} | |
2379 | file can prevent the loading of the terminal-specific library by setting | |
2380 | @code{term-file-prefix} to @code{nil}. | |
2381 | ||
2382 | @vindex term-setup-hook | |
2383 | Emacs runs the hook @code{term-setup-hook} at the end of | |
2384 | initialization, after both your @file{.emacs} file and any | |
2385 | terminal-specific library have been read in. Add hook functions to this | |
2386 | hook if you wish to override part of any of the terminal-specific | |
2387 | libraries and to define initializations for terminals that do not have a | |
2388 | library. @xref{Hooks}. | |
2389 | ||
2390 | @node Find Init | |
2391 | @subsection How Emacs Finds Your Init File | |
2392 | ||
60a96371 | 2393 | Normally Emacs uses the environment variable @env{HOME} to find |
af1b4255 RS |
2394 | @file{.emacs}; that's what @samp{~} means in a file name. If @file{.emacs} |
2395 | is not found directly inside @file{~/}, Emacs looks for it in | |
2396 | @file{~/.emacs.d/}. | |
2397 | ||
2398 | However, if you run Emacs from a shell started by @code{su}, Emacs | |
2399 | tries to find your own @file{.emacs}, not that of the user you are | |
2400 | currently pretending to be. The idea is that you should get your own | |
2401 | editor customizations even if you are running as the super user. | |
6bf7aab6 DL |
2402 | |
2403 | More precisely, Emacs first determines which user's init file to use. | |
60a96371 GM |
2404 | It gets the user name from the environment variables @env{LOGNAME} and |
2405 | @env{USER}; if neither of those exists, it uses effective user-ID. | |
2406 | If that user name matches the real user-ID, then Emacs uses @env{HOME}; | |
6bf7aab6 DL |
2407 | otherwise, it looks up the home directory corresponding to that user |
2408 | name in the system's data base of users. | |
2409 | @c LocalWords: backtab | |
ab5796a9 MB |
2410 | |
2411 | @ignore | |
2412 | arch-tag: c68abddb-4410-4fb5-925f-63394e971d93 | |
2413 | @end ignore |