This chapter talks about various topics relevant to adapting the behavior of Emacs in minor ways.
All kinds of customization affect only the particular Emacs job that you do them in. They are completely lost when you kill the Emacs job, and have no effect on other Emacs jobs you may run at the same time or later. The only way an Emacs job can affect anything outside of it is by writing a file; in particular, the only way to make a customization `permanent' is to put something in your `.emacs' file or other appropriate file to do the customization in each session. See section The Init File, .emacs.
Minor modes are options which you can use or not. For example, Auto Fill mode is a minor mode in which SPC breaks lines between words as you type. All the minor modes are independent of each other and of the selected major mode. Most minor modes inform you in the mode line when they are on; for example, `Fill' in the mode line means that Auto Fill mode is on.
Append -mode to the name of a minor mode to get the name of a
command function that turns the mode on or off. Thus, the command to
enable or disable Auto Fill mode is called M-x auto-fill-mode. These
commands are usually invoked with M-x, but you can bind keys to them
if you wish. With no argument, the function turns the mode on if it was
off and off if it was on. This is known as toggling. A positive
argument always turns the mode on, and an explicit zero argument or a
negative argument always turns it off.
Auto Fill mode allows you to enter filled text without breaking lines explicitly. Emacs inserts newlines as necessary to prevent lines from becoming too long. See section Filling Text.
Overwrite mode causes ordinary printing characters to replace existing text instead of moving it to the right. For example, if point is in front of the `B' in `FOOBAR', and you type a G in Overwrite mode, it changes to `FOOGAR', instead of `FOOGBAR'.
Abbrev mode allows you to define abbreviations that automatically expand as you type them. For example, `amd' might expand to `abbrev mode'. See section Abbrevs, for full information.
A variable is a Lisp symbol which has a value. Variable names can contain any characters, but by convention they are words separated by hyphens. A variable can also have a documentation string, which describes what kind of value it should have and how the value will be used.
Lisp allows any variable to have any kind of value, but most variables
that Emacs uses require a value of a certain type. Often the value has
to be a string or a number. Sometimes we say that a certain feature is
turned on if a variable is "non-nil," meaning that if the
variable's value is nil, the feature is off, but the feature is
on for any other value. The conventional value to turn on the
feature--since you have to pick one particular value when you set the
variable--is t.
Emacs uses many Lisp variables for internal recordkeeping, as any Lisp program must, but the most interesting variables for you are the ones that exist for the sake of customization. Emacs does not (usually) change the values of these variables; instead, you set the values, and thereby alter and control the behavior of certain Emacs commands. These variables are called options. Most options are documented in this manual and appear in the Variable Index (see section Variable Index).
One example of a variable which is an option is fill-column, which
specifies the position of the right margin (as a number of characters from
the left margin) to be used by the fill commands (see section Filling Text).
To examine the value of a single variable, use C-h v
(describe-variable), which reads a variable name using the
minibuffer, with completion. It prints both the value and the
documentation of the variable.
C-h v fill-column RET
prints something like:
fill-column's value is 75 Documentation: *Column beyond which automatic line-wrapping should happen. Automatically becomes local when set in any fashion.
The star at the beginning of the documentation indicates that this variable is an option. C-h v is not restricted to options; it allows any variable name.
If you know which option you want to set, you can use M-x set-variable to set it. This prompts for the variable name in the minibuffer (with completion), and then prompts for a Lisp expression for the new value using the minibuffer a second time. For example,
M-x set-variable RET fill-column RET 75 RET
sets fill-column to 75, as if you had executed the Lisp expression
(setq fill-column 75).
Setting variables in this way, like all means of customizing Emacs except where explicitly stated, affects only the current Emacs session.
M-x list-options displays a list of all Emacs option variables in an Emacs buffer named `*List Options*'. Each option is shown with its documentation and its current value. Here is what a portion of it might look like:
;; exec-path:
("." "/usr/local/bin" "/usr/ucb" "/bin" "/usr/bin" "/u2/emacs/etc")
*List of directories to search programs to run in subprocesses.
Each element is a string (directory name)
or nil (try the default directory).
;;
;; fill-column:
75
*Column beyond which automatic line-wrapping should happen.
Automatically becomes local when set in any fashion.
;;
M-x edit-options goes one step further and immediately selects the `*List Options*' buffer; this buffer uses the major mode Options mode, which provides commands that allow you to point at an option and change its value:
nil,
it becomes t; otherwise it becomes nil.
t.
nil.
You can make any variable local to a specific Emacs buffer. This means that the variable's value in that buffer is independent of its value in other buffers. A few variables are always local in every buffer. All other Emacs variables have a global value which is in effect in all buffers that have not made the variable local.
Major modes always make the variables they set local to the buffer. This is why changing major modes in one buffer has no effect on other buffers.
M-x make-local-variable reads the name of a variable and makes it local to the current buffer. Further changes in this buffer will not affect others, and changes in the global value will not affect this buffer.
M-x make-variable-buffer-local reads the name of a variable and
changes the future behavior of the variable so that it automatically
becomes local when it is set. More precisely, once you have marked a
variable in this way, the usual ways of setting the
variable will automatically invoke make-local-variable first. We
call such variables per-buffer variables.
Some important variables have been marked per-buffer already. They
include abbrev-mode, auto-fill-function,
case-fold-search, comment-column, ctl-arrow,
fill-column, fill-prefix, indent-tabs-mode,
left-margin, mode-line-format, overwrite-mode,
selective-display-ellipses, selective-display,
tab-width, and truncate-lines. Some other variables are
always local in every buffer, but they are used for internal
purposes.
Note: the variable auto-fill-function was formerly named
auto-fill-hook.
If you want a variable to cease to be local to the current buffer, call M-x kill-local-variable and provide the name of a variable to the prompt. The global value of the variable is again in effect in this buffer. Setting the major mode kills all the local variables of the buffer.
To set the global value of a variable, regardless of whether the
variable has a local value in the current buffer, you can use the
Lisp function setq-default. It works like setq.
If there is a local value in the current buffer, the local value is
not affected by setq-default; thus, the new global value may
not be visible until you switch to another buffer, as in the case of:
(setq-default fill-column 75)
setq-default is the only way to set the global value of a variable
that has been marked with make-variable-buffer-local.
Programs can look at a variable's default value with default-value.
This function takes a symbol as an argument and returns its default value.
The argument is evaluated; usually you must quote it explicitly, as in
the case of:
(default-value 'fill-column)
A file can contain a local variables list, which specifies the values to use for certain Emacs variables when that file is edited. Visiting the file checks for a local variables list and makes each variable in the list local to the buffer in which the file is visited, with the value specified in the file.
A local variables list goes near the end of the file, in the last page. (It is often best to put it on a page by itself.) The local variables list starts with a line containing the string `Local Variables:', and ends with a line containing the string `End:'. In between come the variable names and values, one set per line, as `variable: value'. The values are not evaluated; they are used literally.
The line which starts the local variables list does not have to say just `Local Variables:'. If there is other text before `Local Variables:', that text is called the prefix, and if there is other text after, that is called the suffix. If a prefix or suffix are present, each entry in the local variables list should have the prefix before it and the suffix after it. This includes the `End:' line. The prefix and suffix are included to disguise the local variables list as a comment so the compiler or text formatter will ignore it. If you do not need to disguise the local variables list as a comment in this way, there is no need to include a prefix or a suffix.
Two "variable" names are special in a local variables list: a value
for the variable mode sets the major mode, and a value for the
variable eval is simply evaluated as an expression and the value
is ignored. These are not real variables; setting them in any other
context does not have the same effect. If mode is used in a
local variables list, it should be the first entry in the list.
Here is an example of a local variables list:
;;; Local Variables: *** ;;; mode:lisp *** ;;; comment-column:0 *** ;;; comment-start: ";;; " *** ;;; comment-end:"***" *** ;;; End: ***
Note that the prefix is `;;; ' and the suffix is ` ***'. Note also that comments in the file begin with and end with the same strings. Presumably the file contains code in a language which is enough like Lisp for Lisp mode to be useful but in which comments start and end differently. The prefix and suffix are used in the local variables list to make the list look like several lines of comments when the compiler or interpreter for that language reads the file.
The start of the local variables list must be no more than 3000 characters from the end of the file, and must be in the last page if the file is divided into pages. Otherwise, Emacs will not notice it is there. The purpose is twofold: a stray `Local Variables:' not in the last page does not confuse Emacs, and Emacs never needs to search a long file that contains no page markers and has no local variables list.
You may be tempted to turn on Auto Fill mode with a local variable list. That is inappropriate. Whether you use Auto Fill mode or not is a matter of personal taste, not a matter of the contents of particular files. If you want to use Auto Fill, set up major mode hooks with your `.emacs' file to turn it on (when appropriate) for you alone (see section The Init File, .emacs). Don't try to use a local variable list that would impose your taste on everyone working with the file.
XEmacs allows you to specify local variables in the first line
of a file, in addition to specifying them in the Local Variables
section at the end of a file.
If the first line of a file contains two occurences of `-*-', Emacs
uses the information between them to determine what the major mode and
variable settings should be. For example, these are all legal:
;;; -*- mode: emacs-lisp -*- ;;; -*- mode: postscript; version-control: never -*- ;;; -*- tags-file-name: "/foo/bar/TAGS" -*-
For historical reasons, the syntax `-*- modename -*-' is allowed
as well; for example, you can use:
;;; -*- emacs-lisp -*-
The variable enable-local-variables controls the use of local
variables lists in files you visit. The value can be t,
nil, or something else. A value of t means local variables
lists are obeyed; nil means they are ignored; anything else means
query.
The command M-x normal-mode always obeys local variables lists
and ignores this variable.
A keyboard macro is a command defined by the user to abbreviate a sequence of keys. For example, if you discover that you are about to type C-n C-d forty times, you can speed your work by defining a keyboard macro to invoke C-n C-d and calling it with a repeat count of forty.
start-kbd-macro).
end-kbd-macro).
call-last-kbd-macro).
kbd-macro-query).
Keyboard macros differ from other Emacs commands in that they are written in the Emacs command language rather than in Lisp. This makes it easier for the novice to write them and makes them more convenient as temporary hacks. However, the Emacs command language is not powerful enough as a programming language to be useful for writing anything general or complex. For such things, Lisp must be used.
You define a keyboard macro by executing the commands which are its definition. Put differently, as you are defining a keyboard macro, the definition is being executed for the first time. This way, you see what the effects of your commands are, and don't have to figure them out in your head. When you are finished, the keyboard macro is defined and also has been executed once. You can then execute the same set of commands again by invoking the macro.
To start defining a keyboard macro, type C-x (
(start-kbd-macro). From then on, anything you type continues to be
executed, but also becomes part of the definition of the macro. `Def'
appears in the mode line to remind you of what is going on. When you are
finished, the C-x ) command (end-kbd-macro) terminates the
definition, without becoming part of it.
For example,
C-x ( M-f foo C-x )
defines a macro to move forward a word and then insert `foo'.
You can give C-x ) a repeat count as an argument, in which case it repeats the macro that many times right after defining it, but defining the macro counts as the first repetition (since it is executed as you define it). If you give C-x ) an argument of 4, it executes the macro immediately 3 additional times. An argument of zero to C-x e or C-x ) means repeat the macro indefinitely (until it gets an error or you type C-g).
Once you have defined a macro, you can invoke it again with the
C-x e command (call-last-kbd-macro). You can give the
command a repeat count numeric argument to execute the macro many times.
To repeat an operation at regularly spaced places in the text, define a macro and include as part of the macro the commands to move to the next place you want to use it. For example, if you want to change each line, you should position point at the start of a line, and define a macro to change that line and leave point at the start of the next line. Repeating the macro will then operate on successive lines.
After you have terminated the definition of a keyboard macro, you can add to the end of its definition by typing C-u C-x (. This is equivalent to plain C-x ( followed by retyping the whole definition so far. As a consequence it re-executes the macro as previously defined.
To save a keyboard macro for longer than until you define the
next one, you must give it a name using M-x name-last-kbd-macro.
This reads a name as an argument using the minibuffer and defines that name
to execute the macro. The macro name is a Lisp symbol, and defining it in
this way makes it a valid command name for calling with M-x or for
binding a key to with global-set-key (see section Keymaps). If you
specify a name that has a prior definition other than another keyboard
macro, Emacs prints an error message and nothing is changed.
Once a macro has a command name, you can save its definition in a file. You can then use it in another editing session. First visit the file you want to save the definition in. Then use the command:
M-x insert-kbd-macro RET macroname RET
This inserts some Lisp code that, when executed later, will define the same
macro with the same definition it has now. You need not understand Lisp
code to do this, because insert-kbd-macro writes the Lisp code for you.
Then save the file. You can load the file with load-file
(see section Libraries of Lisp Code for Emacs). If the file you save in is your initialization file
`~/.emacs' (see section The Init File, .emacs), then the macro will be defined each
time you run Emacs.
If you give insert-kbd-macro a prefix argument, it creates
additional Lisp code to record the keys (if any) that you have bound to the
keyboard macro, so that the macro is reassigned the same keys when you
load the file.
You can use C-x q (kbd-macro-query), to get an effect similar
to that of query-replace. The macro asks you each time
whether to make a change. When you are defining the macro, type C-x
q at the point where you want the query to occur. During macro
definition, the C-x q does nothing, but when you invoke the macro,
C-x q reads a character from the terminal to decide whether to
continue.
The special answers to a C-x q query are SPC, DEL, C-d, C-l, and C-r. Any other character terminates execution of the keyboard macro and is then read as a command. SPC means to continue. DEL means to skip the remainder of this repetition of the macro, starting again from the beginning in the next repetition. C-d means to skip the remainder of this repetition and cancel further repetition. C-l redraws the frame and asks you again for a character to specify what to do. C-r enters a recursive editing level, in which you can perform editing that is not part of the macro. When you exit the recursive edit using C-M-c, you are asked again how to continue with the keyboard macro. If you type a SPC at this time, the rest of the macro definition is executed. It is up to you to leave point and the text in a state such that the rest of the macro will do what you want.
C-u C-x q, which is C-x q with a numeric argument, performs a different function. It enters a recursive edit reading input from the keyboard, both when you type it during the definition of the macro and when it is executed from the macro. During definition, the editing you do inside the recursive edit does not become part of the macro. During macro execution, the recursive edit gives you a chance to do some particularized editing. See section Recursive Editing Levels.
This section deals with the keymaps that define the bindings between keys and functions, and shows how you can customize these bindings.
A command is a Lisp function whose definition provides for interactive use. Like every Lisp function, a command has a function name, which is a Lisp symbol whose name usually consists of lower case letters and hyphens.
The bindings between characters and command functions are recorded in
data structures called keymaps. Emacs has many of these. One, the
global keymap, defines the meanings of the single-character keys that
are defined regardless of major mode. It is the value of the variable
global-map.
Each major mode has another keymap, its local keymap, which
contains overriding definitions for the single-character keys that are
redefined in that mode. Each buffer records which local keymap is
installed for it at any time, and the current buffer's local keymap is
the only one that directly affects command execution. The local keymaps
for Lisp mode, C mode, and many other major modes always exist even when
not in use. They are the values of the variables lisp-mode-map,
c-mode-map, and so on. For less frequently used major modes, the
local keymap is sometimes constructed only when the mode is used for the
first time in a session, to save space.
There are local keymaps for the minibuffer, too; they contain various completion and exit commands.
minibuffer-local-map is used for ordinary input (no completion).
minibuffer-local-ns-map is similar, except that SPC exits
just like RET. This is used mainly for Mocklisp compatibility.
minibuffer-local-completion-map is for permissive completion.
minibuffer-local-must-match-map is for strict completion and
for cautious completion.
repeat-complex-command-map is for use in C-x ESC.
isearch-mode-map contains the bindings of the special keys which
are bound in the pseudo-mode entered with C-s and C-r.
Finally, each prefix key has a keymap which defines the key sequences
that start with it. For example, ctl-x-map is the keymap used for
characters following a C-x.
ctl-x-map is the variable name for the map used for characters that
follow C-x.
help-map is used for characters that follow C-h.
esc-map is for characters that follow ESC. All Meta
characters are actually defined by this map.
ctl-x-4-map is for characters that follow C-x 4.
mode-specific-map is for characters that follow C-c.
The definition of a prefix key is the keymap to use for looking up
the following character. Sometimes the definition is actually a Lisp
symbol whose function definition is the following character keymap. The
effect is the same, but it provides a command name for the prefix key that
you can use as a description of what the prefix key is for. Thus the
binding of C-x is the symbol Ctl-X-Prefix, whose function
definition is the keymap for C-x commands, the value of
ctl-x-map.
Prefix key definitions can appear in either the global map or a local map. The definitions of C-c, C-x, C-h, and ESC as prefix keys appear in the global map, so these prefix keys are always available. Major modes can locally redefine a key as a prefix by putting a prefix key definition for it in the local map.
A mode can also put a prefix definition of a global prefix character such
as C-x into its local map. This is how major modes override the
definitions of certain keys that start with C-x. This case is
special, because the local definition does not entirely replace the global
one. When both the global and local definitions of a key are other
keymaps, the next character is looked up in both keymaps, with the local
definition overriding the global one. The character after the
C-x is looked up in both the major mode's own keymap for redefined
C-x commands and in ctl-x-map. If the major mode's own keymap
for C-x commands contains nil, the definition from the global
keymap for C-x commands is used.
You can redefine an Emacs key by changing its entry in a keymap. You can change the global keymap, in which case the change is effective in all major modes except those that have their own overriding local definitions for the same key. Or you can change the current buffer's local map, which affects all buffers using the same major mode.
cmd is a symbol naming an interactively-callable function.
When called interactively, key is the next complete key sequence
that you type. When called as a function, key is a string, a
vector of events, or a vector of key-description lists as described in
the define-key function description. The binding goes in
the current buffer's local map, which is shared with other buffers in
the same major mode.
The following example:
M-x global-set-key RET C-f next-line RET
redefines C-f to move down a line. The fact that cmd is read second makes it serve as a kind of confirmation for key.
These functions offer no way to specify a particular prefix keymap as the one to redefine in, but that is not necessary, as you can include prefixes in key. key is read by reading characters one by one until they amount to a complete key (that is, not a prefix key). Thus, if you type C-f for key, Emacs enters the minibuffer immediately to read cmd. But if you type C-x, another character is read; if that character is 4, another character is read, and so on. For example,
M-x global-set-key RET C-x 4 $ spell-other-window RET
redefines C-x 4 $ to run the (fictitious) command
spell-other-window.
The most general way to modify a keymap is the function
define-key, used in Lisp code (such as your `.emacs' file).
define-key takes three arguments: the keymap, the key to modify
in it, and the new definition. See section The Init File, .emacs, for an example.
substitute-key-definition is used similarly; it takes three
arguments, an old definition, a new definition, and a keymap, and
redefines in that keymap all keys that were previously defined with the
old definition to have the new definition instead.
You can use the functions global-set-key and define-key
to rebind keys under program control.
(global-set-key keys cmd)
(define-key keymap keys def)
keys is the sequence of keystrokes to bind.
def is anything that can be a key's definition:
nil, meaning key is undefined in this keymap
(string . defn), meaning that defn is the definition
(defn should be a valid definition in its own right)
(keymap . char), meaning use the definition of
char in map keymap
For backward compatibility, XEmacs allows you to specify key sequences as strings. However, the preferred method is to use the representations of key sequences as vectors of keystrokes. See section Keystrokes, Key Sequences, and Key Bindings, for more information about the rules for constructing key sequences.
Emacs allows you to abbreviate representations for key sequences in most places where there is no ambiguity. Here are some rules for abbreviation:
f1 is equivalent to (f1).
(control a) is equivalent to [(control a)].
65 is equivalent to A. (This is not so much an
abbreviation as an alternate representation.)
Here are some examples of programmatically binding keys:
;;; Bindmy-commandto f1 (global-set-key 'f1 'my-command) ;;; Bindmy-commandto Shift-f1 (global-set-key '(shift f1) 'my-command) ;;; Bindmy-commandto C-c Shift-f1 (global-set-key '[(control c) (shift f1)] 'my-command) ;;; Bindmy-commandto the middle mouse button. (global-set-key 'button2 'my-command) ;;; Bindmy-commandto META CTL Right Mouse Button ;;; in the keymap that is in force when you are runningdired. (define-key dired-mode-map '(meta control button3) 'my-command)
For backward compatibility, you can still use strings to represent key sequences. Thus you can use comands like the following:
;;; Bind end-of-line to C-f
(global-set-key "\C-f" 'end-of-line)
Note, however, that in some cases you may be binding more than one key sequence by using a single command. This situation can arise because in ASCII, C-i and TAB have the same representation. Therefore, when Emacs sees:
(global-set-key "\C-i" 'end-of-line)
it is unclear whether the user intended to bind C-i or TAB. The solution XEmacs adopts is to bind both of these key sequences.
After binding a command to two key sequences with a form like:
(define-key global-map "\^X\^I" 'command-1)
it is possible to redefine only one of those sequences like so:
(define-key global-map [(control x) (control i)] 'command-2) (define-key global-map [(control x) tab] 'command-3)
This applies only when running under a window system. If you are talking to Emacs through an ASCII-only channel, you do not get any of these features.
Here is a table of pairs of key sequences that behave in a similar fashion:
control h backspace
control l clear
control i tab
control m return
control j linefeed
control [ escape
control @ control space
Disabling a command marks it as requiring confirmation before it can be executed. The purpose of disabling a command is to prevent beginning users from executing it by accident and being confused.
The direct mechanism for disabling a command is to have a non-nil
disabled property on the Lisp symbol for the command. These
properties are normally set by the user's `.emacs' file with
Lisp expressions such as:
(put 'delete-region 'disabled t)
If the value of the disabled property is a string, that string
is included in the message printed when the command is used:
(put 'delete-region 'disabled
"Text deleted this way cannot be yanked back!\n")
You can disable a command either by editing the `.emacs' file directly or with the command M-x disable-command, which edits the `.emacs' file for you. See section The Init File, .emacs.
When you attempt to invoke a disabled command interactively in Emacs, a window is displayed containing the command's name, its documentation, and some instructions on what to do next; then Emacs asks for input saying whether to execute the command as requested, enable it and execute, or cancel it. If you decide to enable the command, you are asked whether to do this permanently or just for the current session. Enabling permanently works by automatically editing your `.emacs' file. You can use M-x enable-command at any time to enable any command permanently.
Whether a command is disabled is independent of what key is used to invoke it; it also applies if the command is invoked using M-x. Disabling a command has no effect on calling it as a function from Lisp programs.
All the Emacs commands which parse words or balance parentheses are controlled by the syntax table. The syntax table specifies which characters are opening delimiters, which are parts of words, which are string quotes, and so on. Actually, each major mode has its own syntax table (though sometimes related major modes use the same one) which it installs in each buffer that uses that major mode. The syntax table installed in the current buffer is the one that all commands use, so we call it "the" syntax table. A syntax table is a Lisp object, a vector of length 256 whose elements are numbers.
The syntax table entry for a character is a number that encodes six pieces of information:
The syntactic classes are stored internally as small integers, but are usually described to or by the user with characters. For example, `(' is used to specify the syntactic class of opening delimiters. Here is a table of syntactic classes, with the characters that specify them.
The characters flagged as part of two-character comment delimiters can
have other syntactic functions most of the time. For example, `/' and
`*' in C code, when found separately, have nothing to do with
comments. The comment-delimiter significance overrides when the pair of
characters occur together in the proper order. Only the list and sexp
commands use the syntax table to find comments; the commands specifically
for comments have other variables that tell them where to find comments.
Moreover, the list and sexp commands notice comments only if
parse-sexp-ignore-comments is non-nil. This variable is set
to nil in modes where comment-terminator sequences are liable to
appear where there is no comment, for example, in Lisp mode where the
comment terminator is a newline but not every newline ends a comment.
It is possible to alter a character's syntax table entry by storing a new number in the appropriate element of the syntax table, but it would be hard to determine what number to use. Emacs therefore provides a command that allows you to specify the syntactic properties of a character in a convenient way.
M-x modify-syntax-entry is the command to change a character's syntax. It can be used interactively and is also used by major modes to initialize their own syntax tables. Its first argument is the character to change. The second argument is a string that specifies the new syntax. When called from Lisp code, there is a third, optional argument, which specifies the syntax table in which to make the change. If not supplied, or if this command is called interactively, the third argument defaults to the current buffer's syntax table.
Use C-h s (describe-syntax) to display a description of
the contents of the current syntax table. The description of each
character includes both the string you have to pass to
modify-syntax-entry to set up that character's current syntax,
and some English to explain that string if necessary.
When you start Emacs, it normally loads the file `.emacs' in your home directory. This file, if it exists, should contain Lisp code. It is called your initialization file or init file. Use the command line switches `-q' and `-u' to tell Emacs whether to load an init file (see section Entering and Exiting Emacs).
When the `.emacs' file is read, the variable init-file-user
says which user's init file it is. The value may be the null string or a
string containing a user's name. If the value is a null string, it means
that the init file was taken from the user that originally logged in.
In all cases, (concat "~" init-file-user "/") evaluates to the
directory name of the directory where the `.emacs' file was looked
for.
At some sites there is a default init file, which is the
library named `default.el', found via the standard search path for
libraries. The Emacs distribution contains no such library; your site
may create one for local customizations. If this library exists, it is
loaded whenever you start Emacs. But your init file, if any, is loaded
first; if it sets inhibit-default-init non-nil, then
`default' is not loaded.
If you have a large amount of code in your `.emacs' file, you
should move it into another file named `something.el',
byte-compile it (see section Libraries of Lisp Code for Emacs), and load that file from your
`.emacs' file using load.
The `.emacs' file contains one or more Lisp function call
expressions. Each consists of a function name followed by
arguments, all surrounded by parentheses. For example, (setq
fill-column 60) represents a call to the function setq which is
used to set the variable fill-column (see section Filling Text) to 60.
The second argument to setq is an expression for the new value
of the variable. This can be a constant, a variable, or a function call
expression. In `.emacs', constants are used most of the time.
They can be:
?x, ?\n, ?\", ?\). Note that
strings and characters are not interchangeable in Lisp; some contexts
require one and some contexts require the other.
t stands for `true'.
nil stands for `false'.
Here are some examples of doing certain commonly desired things with Lisp expressions:
(setq c-tab-always-indent nil)Here we have a variable whose value is normally
t for `true'
and the alternative is nil for `false'.
(setq-default case-fold-search nil)This sets the default value, which is effective in all buffers that do not have local values for the variable. Setting
case-fold-search
with setq affects only the current buffer's local value, which
is probably not what you want to do in an init file.
(setq default-major-mode 'text-mode)Note that
text-mode is used because it is the command for entering
the mode we want. A single-quote is written before it to make a symbol
constant; otherwise, text-mode would be treated as a variable name.
(setq text-mode-hook '(lambda () (auto-fill-mode 1)))Here we have a variable whose value should be a Lisp function. The function we supply is a list starting with
lambda, and a single
quote is written in front of it to make it (for the purpose of this
setq) a list constant rather than an expression. Lisp functions
are not explained here; for mode hooks it is enough to know that
(auto-fill-mode 1) is an expression that will be executed when
Text mode is entered. You could replace it with any other expression
that you like, or with several expressions in a row.
(setq text-mode-hook 'turn-on-auto-fill)This is another way to accomplish the same result.
turn-on-auto-fill is a symbol whose function definition is
(lambda () (auto-fill-mode 1)).
(load "foo")When the argument to
load is a relative pathname, not starting
with `/' or `~', load searches the directories in
load-path (see section Loading Libraries).
(load "~/foo.elc")Here an absolute file name is used, so no searching is done.
make-symbolic-link.
(global-set-key "\C-xl" 'make-symbolic-link)or
(define-key global-map "\C-xl" 'make-symbolic-link)Note once again the single-quote used to refer to the symbol
make-symbolic-link instead of its value as a variable.
(define-key c-mode-map "\C-xl" 'make-symbolic-link)
(define-key c-mode-map 'f1 'make-symbolic-link)
(define-key c-mode-map '(shift f1) 'make-symbolic-link)
next-line in Fundamental mode
to run forward-line instead.
(substitute-key-definition 'next-line 'forward-line global-map)
(global-unset-key "\C-x\C-v")One reason to undefine a key is so that you can make it a prefix. Simply defining C-x C-v anything would make C-x C-v a prefix, but C-x C-v must be freed of any non-prefix definition first.
(modify-syntax-entry ?\$ "." text-mode-syntax-table)
eval-expression without confirmation.
(put 'eval-expression 'disabled nil)
Each terminal type can have a Lisp library to be loaded into Emacs when
it is run on that type of terminal. For a terminal type named
termtype, the library is called `term/termtype' and it is
found by searching the directories load-path as usual and trying the
suffixes `.elc' and `.el'. Normally it appears in the
subdirectory `term' of the directory where most Emacs libraries are
kept.
The usual purpose of the terminal-specific library is to define the escape sequences used by the terminal's function keys using the library `keypad.el'. See the file `term/vt100.el' for an example of how this is done.
When the terminal type contains a hyphen, only the part of the name
before the first hyphen is significant in choosing the library name.
Thus, terminal types `aaa-48' and `aaa-30-rv' both use
the library `term/aaa'. The code in the library can use
(getenv "TERM") to find the full terminal type name.
The library's name is constructed by concatenating the value of the
variable term-file-prefix and the terminal type. Your `.emacs'
file can prevent the loading of the terminal-specific library by setting
term-file-prefix to nil.
The value of the variable term-setup-hook, if not nil, is
called as a function of no arguments at the end of Emacs initialization,
after both your `.emacs' file and any terminal-specific library have
been read. You can set the value in the `.emacs' file to override
part of any of the terminal-specific libraries and to define
initializations for terminals that do not have a library.
You can now change how the audible bell sounds using the variable
sound-alist.
sound-alist's value is an list associating symbols with, among
other things, strings of audio-data. When ding is called with
one of the symbols, the associated sound data is played instead of the
standard beep. This only works if you are logged in on the console of a
machine with audio hardware. To listen to a sound of the provided type,
call the function play-sound with the argument sound. You
can also set the volume of the sound with the optional argument
volume.
Each element of sound-alist is a list describing a sound.
The first element of the list is the name of the sound being defined.
Subsequent elements of the list are alternating keyword/value pairs:
sound
t here means use the default X beep.
volume
bell-volume.
pitch
duration
For compatibility, elements of `sound-alist' may also be of the form:
( sound-name . <sound> ) ( sound-name <volume> <sound> )
You should probably add things to this list by calling the function
load-sound-file.
Note that you can only play audio data if running on the console screen of a machine with audio hardware which emacs understands, which at this time means a Sun SparcStation, SGI, or HP9000s700.
Also note that the pitch, duration, and volume options are available everywhere, but most X servers ignore the `pitch' option.
The variable bell-volume should be an integer from 0 to 100,
with 100 being loudest, which controls how loud the sounds emacs makes
should be. Elements of the sound-alist may override this value.
This variable applies to the standard X bell sound as well as sound files.
If the symbol t is in place of a sound-string, Emacs uses the
default X beep. This allows you to define beep-types of
different volumes even when not running on the console.
You can add things to this list by calling the function
load-sound-file, which reads in an audio-file and adds its data to
the sound-alist. You can specify the sound with the sound-name
argument and the file into which the sounds are loaded with the
filename argument. The optional volume argument sets the
volume.
load-sound-file (filename sound-name &optional volume)
To load and install some sound files as beep-types, use the function
load-default-sounds (note that this only works if you are on
display 0 of a machine with audio hardware).
The following beep-types are used by Emacs itself. Other Lisp packages may use other beep types, but these are the ones that the C kernel of Emacs uses.
auto-save-error
command-error
undefined-key
undefined-click
no-completion
y-or-n-p
y or n
yes-or-no-p
yes or no
XEmacs has objects called extents and faces. An extent is a region of text and a face is a collection of textual attributes, such as fonts and colors. Every extent is displayed in some face; therefore, changing the properties of a face immediately updates the display of all associated extents. Faces can be frame-local: you can have a region of text that displays with completely different attributes when its buffer is viewed from a different X window.
The display attributes of faces may be specified either in Lisp or through the X resource manager.
You can change the face of an extent with the functions in this section. All the functions prompt for a face as an argument; use completion for a list of possible values.
nil if this is not possible.
nil if not possible.
nil if not possible.
nil if not possible.
nil if not possible.
nil if not possible.
nil if not possible.
You can exchange the foreground and background color of the selected
face with the function invert-face. If the face does not
specify both foreground and background, then its foreground and
background are set to the background and foreground of the default face.
When calling this from a program, you can supply the optional argument
frame to specify which frame is affected; otherwise, all frames
are affected.
You can set the background color of the specified face with the
function set-face-background. The argument color should
be a string, the name of a color. When called from a program, if the
optional frame argument is provided, the face is changed only
in that frame; otherwise, it is changed in all frames.
You can set the background pixmap of the specified face with the
function set-face-background-pixmap. The pixmap argument
name should be a string, the name of a file of pixmap data. The
directories listed in the x-bitmap-file-path variable are
searched. The bitmap may also be a list of the form (width
height data), where width and height are the size in
pixels, and data is a string containing the raw bits of the
bitmap. If the optional frame argument is provided, the face is
changed only in that frame; otherwise, it is changed in all frames.
The variable x-bitmap-file-path takes as a value a list of the
directories in which X bitmap files may be found. If the value is
nil, the list is initialized from the *bitmapFilePath
resource.
If the environment variable XBMLANGPATH is set, then it is consulted
before the x-bitmap-file-path variable.
You can set the font of the specified face with the function
set-face-font. The font argument should be a string, the
name of a font. When called from a program, if the
optional frame argument is provided, the face is changed only
in that frame; otherwise, it is changed in all frames.
You can set the foreground color of the specified face with the
function set-face-foreground. The argument color should be
a string, the name of a color. If the optional frame argument is
provided, the face is changed only in that frame; otherwise, it is
changed in all frames.
You can set underline the specified face with the function
set-face-underline-p. The argument underline-p can be used
to make underlining an attribute of the face or not. If the optional
frame argument is provided, the face is changed only in that
frame; otherwise, it is changed in all frames.
The Emacs resources are generally set per-frame. Each Emacs frame can have
its own name or the same name as another, depending on the name passed to the
make-frame function.
You can specify resources for all frames with the syntax:
Emacs*parameter: value
or
Emacs*EmacsFrame.parameter:value
You can specify resources for a particular frame with the syntax:
Emacs*FRAME-NAME.parameter: value
To make the default size of all Emacs frames be 80 columns by 55 lines, do this:
Emacs*EmacsFrame.geometry: 80x55
To set the geometry of a particular frame named `fred', do this:
Emacs*fred.geometry: 80x55
Important! Do not use the following syntax:
Emacs*geometry: 80x55
You should never use *geometry with any X application. It does
not say "make the geometry of Emacs be 80 columns by 55 lines." It
really says, "make Emacs and all subwindows thereof be 80x55 in whatever
units they care to measure in." In particular, that is both telling the
Emacs text pane to be 80x55 in characters, and telling the menubar pane
to be 80x55 pixels, which is surely not what you want.
As a special case, this geometry specification also works (and sets the default size of all Emacs frames to 80 columns by 55 lines):
Emacs.geometry: 80x55
since that is the syntax used with most other applications (since most other applications have only one top-level window, unlike Emacs). In general, however, the top-level shell (the unmapped ApplicationShell widget named `Emacs' that is the parent of the shell widgets that actually manage the individual frames) does not have any interesting resources on it, and you should set the resources on the frames instead.
The -geometry command-line argument sets only the geometry of the
initial frame created by Emacs.
A more complete explanation of geometry-handling is
-geometry command-line option sets the Emacs.geometry
resource, that is, the geometry of the ApplicationShell.
Emacs.geometry) if it is specified, otherwise
from the geometry of the frame.
This is rather complicated, but it does seem to provide the most intuitive behavior with respect to the default sizes and positions of frames created in various ways.
Analogous to -geometry, the -iconic command-line option
sets the iconic flag of the ApplicationShell (Emacs.iconic) and
always applies to the first frame created regardless of its name.
However, it is possible to set the iconic flag on particular frames (by
name) by using the Emacs*FRAME-NAME.iconic resource.
Emacs frames accept the following resources:
geometry (class Geometry): string
iconic (class Iconic): boolean
internalBorderWidth (class InternalBorderWidth): int
interline (class Interline): int
menubar (class Menubar): boolean
initiallyUnmapped (class InitiallyUnmapped): boolean
-unmapped command-line option.
barCursor (class BarColor): boolean
cursorColor (class CursorColor): color-name
scrollBarWidth (class ScrollBarWidth): integer
*scrollbar.width, or the usual toolkit scrollbar resources:
*XmScrollBar.width (Motif), *XlwScrollBar.width (Lucid),
or *Scrollbar.thickness (Athena). We don't recommend that you
use the toolkit resources, though, because they're dependent on how
exactly your particular build of XEmacs was configured.
scrollBarHeight (class ScrollBarHeight): integer
*scrollbar.height, or the usual toolkit scrollbar resources:
*XmScrollBar.height (Motif), *XlwScrollBar.height (Lucid),
or *Scrollbar.thickness (Athena). We don't recommend that you use
the toolkit resources, though, because they're dependent on how exactly
your particular build of XEmacs was configured.
scrollBarPlacement (class ScrollBarPlacement): string
topToolBarHeight (class TopToolBarHeight): integer
bottomToolBarHeight (class BottomToolBarHeight): integer
leftToolBarWidth (class LeftToolBarWidth): integer
rightToolBarWidth (class RightToolBarWidth): integer
topToolBarShadowColor (class TopToolBarShadowColor): color-name
bottomToolBarShadowColor (class BottomToolBarShadowColor): color-name
topToolBarShadowPixmap (class TopToolBarShadowPixmap): pixmap-name
bottomToolBarShadowPixmap (class BottomToolBarShadowPixmap): pixmap-name
toolBarShadowThickness (class ToolBarShadowThickness): integer
visualBell (class VisualBell): boolean
bellVolume (class BellVolume): integer
useBackingStore (class UseBackingStore): boolean
Emacs devices accept the following resources:
textPointer (class Cursor): cursor-name
x-pointer-shape.
selectionPointer (class Cursor): cursor-name
x-selection-pointer-shape.
spacePointer (class Cursor): cursor-name
x-nontext-pointer-shape.
modeLinePointer (class Cursor): cursor-name
x-mode-pointer-shape.
gcPointer (class Cursor): cursor-name
x-gc-pointer-shape.
scrollbarPointer (class Cursor): cursor-name
x-scrollbar-pointer-shape.
pointerColor (class Foreground): color-name
pointerBackground (class Background): color-name
x-pointer-foreground-color and x-pointer-background-color.
The attributes of faces are also per-frame. They can be specified as:
Emacs*FACE_NAME.parameter: value
or
Emacs*FRAME_NAME.FACE_NAME.parameter: value
Faces accept the following resources:
attributeFont (class AttributeFont): font-name
attributeForeground (class AttributeForeground): color-name
attributeBackground (class AttributeBackground): color-name
attributeBackgroundPixmap (class AttributeBackgroundPixmap): file-name
attributeUnderline (class AttributeUnderline): boolean
All text is displayed in some face, defaulting to the face named
default. To set the font of normal text, use
Emacs*default.attributeFont. To set it in the frame named
fred, use Emacs*fred.default.attributeFont.
These are the names of the predefined faces:
default
bold
italic
bold-italic
modeline
highlight
left-margin
right-margin
primary-selection
isearch
info-node
bold-italic.
info-xref
bold. (Note that, when the mouse passes over a
cross-reference, the cross-reference's face is determined from a
combination of the info-xref and highlight faces.)
Other packages might define their own faces; to see a list of all faces,
use any of the interactive face-manipulation commands such as
set-face-font and type `?' when you are prompted for the
name of a face.
If the bold, italic, and bold-italic faces are not
specified in the resource database, then XEmacs attempts to derive them
from the font of the default face. It can only succeed at this if you
have specified the default font using the XLFD (X Logical Font
Description) format, which looks like
*-courier-medium-r-*-*-*-120-*-*-*-*-*-*
If you use any of the other, less strict font name formats, some of which look like
lucidasanstypewriter-12 fixed 9x13
then XEmacs won't be able to guess the names of the bold and italic versions. All X fonts can be referred to via XLFD-style names, so you should use those forms. See the man pages for `X(1)', `xlsfonts(1)', and `xfontsel(1)'.
There are several structural widgets between the terminal EmacsFrame widget and the top level ApplicationShell; the exact names and types of these widgets change from release to release (for example, they changed between 19.8 and 19.9, 19.9 and 19.10, and 19.10 and 19.12) and are subject to further change in the future, so you should avoid mentioning them in your resource database. The above-mentioned syntaxes should be forward- compatible. As of 19.13, the exact widget hierarchy is as follows:
INVOCATION-NAME "shell" "container" FRAME-NAME x-emacs-application-class "EmacsShell" "EmacsManager" "EmacsFrame"
where INVOCATION-NAME is the terminal component of the name of the XEmacs executable (usually `xemacs'), and `x-emacs-application-class' is generally `Emacs'.
As the menubar is implemented as a widget which is not a part of XEacs proper, it does not use the fac" mechanism for specifying fonts and colors: It uses whatever resources are appropriate to the type of widget which is used to implement it.
If Emacs was compiled to use only the Motif-lookalike menu widgets, then one way to specify the font of the menubar would be
Emacs*menubar*font: *-courier-medium-r-*-*-*-120-*-*-*-*-*-*
If the Motif library is being used, then one would have to use
Emacs*menubar*fontList: *-courier-medium-r-*-*-*-120-*-*-*-*-*-*
because the Motif library uses the fontList resource name instead
of font, which has subtly different semantics.
The same is true of the scrollbars: They accept whichever resources are appropriate for the toolkit in use.