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This is Info file ../info/emacs, produced by Makeinfo-1.54 from the
input file emacs.texi.
File: emacs, Node: File Variables, Prev: Locals, Up: Variables
Local Variables in Files
------------------------
A file can specify local variable values for use when you edit the
file with Emacs. Visiting the file checks for local variables
specifications; it automatically makes these variables local to the
buffer, and sets them to the values specified in the file.
There are two ways to specify local variable values: in the first
line, or with a local variables list. Here's how to do this with the
first line:
-*- mode: MODENAME; VAR: VALUE; ... -*-
You can specify any number of variables/value pairs in this way, each
pair with a colon and semicolon as shown above. The major mode should
come first, if it is mentioned at all. Here is an example that
specifies Lisp mode and sets two variables with numeric values:
;; -*-Mode: Lisp; fill-column: 75; comment-column: 50; -*-
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.
Here is an example of a local variables list:
;;; Local Variables: ***
;;; mode:lisp ***
;;; comment-column:0 ***
;;; comment-start: ";;; " ***
;;; comment-end:"***" ***
;;; End: ***
As you see, each line starts with the prefix `;;; ' and each line
ends with the suffix ` ***'. Emacs recognizes these as the prefix and
suffix based on the first line of the list, by finding them surrounding
the magic string `Local Variables:'; so it automatically discards them
from the other lines of the list.
The usual reason for using a prefix and/or suffix is to embed the
local variables list in a comment, so it won't confuse other programs
that the file is intended as input for. The example above is for a
language where comment lines start with `;;; ' and end with `***'; the
local values for `comment-start' and `comment-end' customize the rest
of Emacs for this unusual syntax. Don't use a prefix (or a suffix) if
you don't need one.
Two "variable names" have special meanings in a local variables
list: a value for the variable `mode' really sets the major mode, and a
value for the variable `eval' is simply evaluated as an expression and
the value is ignored. `mode' and `eval' are not real variables;
setting such variables in any other context has no such effect. If
`mode' is used in a local variables list, it should be the first entry
in the list.
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 of this is so that a stray `Local Variables:' not
in the last page does not confuse Emacs, and so that visiting a long
file that is all one page and has no local variables list need not take
the time to search the whole file.
You may be tempted to try to turn on Auto Fill mode with a local
variable list. That is a mistake. The choice of Auto Fill mode or not
is a matter of individual 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 (*note Init File::.). Don't try to use a local variable list
that would impose your taste on everyone.
The variable `enable-local-variables' controls whether to process
local variables lists, and thus gives you a chance to override them.
Its default value is `t', which means to process local variables lists.
If you set the value to `nil', Emacs simply ignores local variables
lists. Any other value says to query you about each local variables
list, showing you the local variables list to consider.
The `eval' "variable" creates special risks, so there is a separate
variable `enable-local-eval' to control whether Emacs processes `eval'
variables. The three possibilities for the value are `t', `nil', and
anything else, just as for `enable-local-variables'. The default is
`maybe', which is neither `t' nor `nil', so normally Emacs queries about
`eval' variable settings.
Use the command `normal-mode' to reset the local variables and major
mode of a buffer according to the file name and contents, including the
local variables list if any. *Note Choosing Modes::.
File: emacs, Node: Keyboard Macros, Next: Key Bindings, Prev: Variables, Up: Customization
Keyboard Macros
===============
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 do `C-n C-d' and calling it with a repeat count of
forty.
`C-x ('
Start defining a keyboard macro (`start-kbd-macro').
`C-x )'
End the definition of a keyboard macro (`end-kbd-macro').
`C-x e'
Execute the most recent keyboard macro (`call-last-kbd-macro').
`C-u C-x ('
Re-execute last keyboard macro, then add more keys to its
definition.
`C-x q'
When this point is reached during macro execution, ask for
confirmation (`kbd-macro-query').
`M-x name-last-kbd-macro'
Give a command name (for the duration of the session) to the most
recently defined keyboard macro.
`M-x insert-kbd-macro'
Insert in the buffer a keyboard macro's definition, as Lisp code.
Keyboard macros differ from ordinary 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
intelligent or general. For such things, Lisp must be used.
You define a keyboard macro while executing the commands which are
the definition. Put differently, as you define a keyboard macro, the
definition is being executed for the first time. This way, you can see
what the effects of your commands are, so that you don't have to figure
them out in your head. When you are finished, the keyboard macro is
defined and also has been, in effect, executed once. You can then do
the whole thing over again by invoking the macro.
* Menu:
* Basic Kbd Macro:: Defining and running keyboard macros.
* Save Kbd Macro:: Giving keyboard macros names; saving them in files.
* Kbd Macro Query:: Keyboard macros that do different things each use.
File: emacs, Node: Basic Kbd Macro, Next: Save Kbd Macro, Up: Keyboard Macros
Basic Use
---------
To start defining a keyboard macro, type the `C-x (' command
(`start-kbd-macro'). From then on, your keys continue to be executed,
but also become 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'.
The macro thus defined can be invoked again with the `C-x e' command
(`call-last-kbd-macro'), which may be given a repeat count as a numeric
argument to execute the macro many times. `C-x )' can also be given 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). So,
giving `C-x )' an argument of 4 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').
If you wish 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. Then repeating the macro will 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.
You can use function keys in a keyboard macro, just like keyboard
keys. You can even use mouse events, but be careful about that: when
the macro replays the mouse event, it uses the original mouse position
of that event, the position that the mouse had while you were defining
the macro. The effect of this may be hard to predict. (Using the
current mouse position would be even less predictable.)
One thing that doesn't always work well in a keyboard macro is the
command `C-M-c' (`exit-recursive-edit'). When this command exits a
recursive edit that started within the macro, it works as you'd expect.
But if it exits a recursive edit that started before you invoked the
keyboard macro, it also necessarily exits the keyboard macro as part of
the process.
File: emacs, Node: Save Kbd Macro, Next: Kbd Macro Query, Prev: Basic Kbd Macro, Up: Keyboard Macros
Naming and Saving Keyboard Macros
---------------------------------
If you wish 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' (*note Keymaps::.). If you specify a name that has a
prior definition other than another keyboard macro, an error message is
printed and nothing is changed.
Once a macro has a command name, you can save its definition in a
file. Then it can be used in another editing session. First, visit
the file you want to save the definition in. Then use this 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 later
with `load-file' (*note Lisp Libraries::.). If the file you save in is
your init file `~/.emacs' (*note Init File::.) then the macro will be
defined each time you run Emacs.
If you give `insert-kbd-macro' a prefix argument, it makes
additional Lisp code to record the keys (if any) that you have bound to
the keyboard macro, so that the macro will be reassigned the same keys
when you load the file.
File: emacs, Node: Kbd Macro Query, Prev: Save Kbd Macro, Up: Keyboard Macros
Executing Macros with Variations
--------------------------------
Using `C-x q' (`kbd-macro-query'), you can get an effect similar to
that of `query-replace', where the macro asks you each time around
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 run the macro later,
`C-x q' asks you interactively whether to continue.
The valid responses when `C-x q' asks are SPC (or `y'), DEL (or
`n'), ESC (or `q'), `C-l' and `C-r'. The answers are the same as in
query replace, though not all of the query-replace options are
meaningful.
Specifically, SPC means to continue. DEL means to skip the
remainder of this repetition of the macro and start right away with the
next repetition. ESC means to skip the remainder of this repetition
and cancel further repetition. `C-l' redraws the screen and asks you
again for a character to say what to do.
`C-r' enters a recursive editing level, in which you can perform
editing which 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. *Note Recursive Edit::.
File: emacs, Node: Key Bindings, Next: Keyboard Translations, Prev: Keyboard Macros, Up: Customization
Customizing Key Bindings
========================
This section describes "key bindings" which map keys to commands,
and the "keymaps" which record key bindings. It also explains how to
customize key bindings.
Recall that a command is a Lisp function whose definition provides
for interactive use. Like every Lisp function, a command has a function
name which usually consists of lower case letters and hyphens.
* Menu:
* Keymaps:: Generalities. The global keymap.
* Prefix Keymaps:: Keymaps for prefix keys.
* Local Keymaps:: Major and minor modes have their own keymaps.
* Minibuffer Maps:: The minibuffer uses its own local keymaps.
* Rebinding:: How to redefine one key's meaning conveniently.
* Init Rebinding:: Rebinding keys with your init file, `.emacs'.
* Function Keys:: Rebinding terminal function keys.
* Mouse Buttons:: Rebinding mouse buttons in Emacs.
* Disabling:: Disabling a command means confirmation is required
before it can be executed. This is done to protect
beginners from surprises.
File: emacs, Node: Keymaps, Next: Prefix Keymaps, Up: Key Bindings
Keymaps
-------
The bindings between key sequences and command functions are recorded
in data structures called "keymaps". Emacs has many of these, each
used on particular occasions.
Recall that a "key sequence" ("key", for short) is a sequence of
"input events" that have a meaning as a unit. Input events include
characters, function keys and mouse buttons--all the inputs that you
can send to the computer with your terminal. A key sequence gets its
meaning from its "binding", which says what command it runs. The
function of keymaps is to record these bindings.
The "global" keymap is the most important keymap because it is
always in effect. The global keymap defines keys for Fundamental mode;
most of these definitions are common to all (or most) major modes. Each
major or minor mode can have its own keymap which overrides the
definitions of some keys.
For example, a self-inserting character such as `g' is
self-inserting because the global keymap binds it to the command
`self-insert-command'. The standard Emacs editing characters such as
`C-a' also get their standard meanings from the global keymap.
Commands to rebind keys, such as `M-x global-set-key', actually work by
storing the new binding in the proper place in the global map. *Note
Rebinding::.
Meta characters work differently; Emacs translates each Meta
character into a pair of characters starting with ESC. When you type
the character `M-a' in a key sequence, Emacs replaces it with `ESC a'.
A meta key comes in as a single input event, but becomes two events for
purposes of key bindings. The reason for this is historical, and we
might change in someday.
Most modern keyboards have function keys as well as character keys.
Function keys send input events just as character keys do, and keymaps
can have bindings for them.
On many terminals, typing a function key actually sends the computer
a sequence of characters; the precise details of the sequence depends on
which function key and on the model of terminal you are using. (Often
he sequence starts with `ESC ['.) If Emacs understands your terminal
type properly, it recognizes the character sequences forming function
keys wherever they occur in a key sequence (not just at the beginning).
Thus, for most purposes, you can pretend the function keys reach Emacs
directly and ignore their encoding as character sequences.
Mouse buttons also produce input events. These events come with
other data--the window and position where you pressed or released the
button, and a timestamp. But only the choice of button matters for key
bindings; the other data matters only if a command looks at it.
(Commands designed for mouse invocation usually do look at the other
data.)
A keymap records definitions for single events. Interpreting a key
sequence of multiple events involves a chain of keymaps. The first
keymap gives a definition for the first event; this definition is
another keymap, which is used to look up the second event in the
sequence, and so on.
Key sequences can mix function keys and characters. For example,
`C-x SELECT' makes sense. If you make SELECT a prefix key, then
`SELECT C-n' makes sense. You can even mix mouse events with keyboard
events, but we recommend against it, because such sequences are
inconvenient to type in.
File: emacs, Node: Prefix Keymaps, Next: Local Keymaps, Prev: Keymaps, Up: Key Bindings
Prefix Keymaps
--------------
A prefix key such as `C-x' or ESC has its own keymap, which holds
the definition for the event that immediately follows that prefix.
The definition of a prefix key is the keymap to use for looking up
the following event. The definition can also be a Lisp symbol whose
function definition is the following keymap; the effect is the same, but
it provides a command name for the prefix key that can be used 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 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.
Some prefix keymaps are stored in variables with names:
* `ctl-x-map' is the variable name for the map used for characters
that follow `C-x'.
* `help-map' is for characters that follow `C-h'.
* `esc-map' is for characters that follow ESC. Thus, 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'.
File: emacs, Node: Local Keymaps, Next: Minibuffer Maps, Prev: Prefix Keymaps, Up: Key Bindings
Local Keymaps
-------------
So far we have explained the ins and outs of the global map. Major
modes customize Emacs by providing their own key bindings in "local
keymaps". For example, C mode overrides TAB to make it indent the
current line for C code. Portions of text in the buffer can specify
their own keymaps to substitute for the keymap of the buffer's major
mode.
Minor modes can also have local keymaps. Whenever a minor mode is
in effect, the definitions in its keymap override both the major mode's
local keymap and the global keymap.
The local keymaps for Lisp mode, C mode, and several other major
modes always exist even when not in use. These are kept in variables
named `lisp-mode-map', `c-mode-map', and so on. For major modes less
often used, the local keymap is normally constructed only when the mode
is used for the first time in a session. This is to save space.
All minor mode keymaps are created in advance. There is no way to
defer their creation until the minor mode is enabled.
A local keymap can locally redefine a key as a prefix key by defining
it as a prefix keymap. If the key is also defined globally as a prefix,
then its local and global definitions (both keymaps) effectively
combine: both of them are used to look up the event that follows the
prefix key. Thus, if the mode's local keymap defines `C-c' as another
keymap, and that keymap defines `C-z' as a command, this provides a
local meaning for `C-c C-z'. This does not affect other sequences that
start with `C-c'; If those sequences don't have their own local
bindings, their global bindings remain in effect.
Another way to think of this is that Emacs handles a multi-event key
sequence by looking in several keymaps, one by one, for a binding of the
whole key sequence. First it checks the minor mode keymaps for minor
modes that are enabled, then it checks the major mode's keymap, and then
it checks the global keymap. This is not precisely how key lookup
works, but it's good enough for understanding ordinary circumstances.
File: emacs, Node: Minibuffer Maps, Next: Rebinding, Prev: Local Keymaps, Up: Key Bindings
Minibuffer Keymaps
------------------
The minibuffer has its own set of local keymaps; 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.
File: emacs, Node: Rebinding, Next: Init Rebinding, Prev: Minibuffer Maps, Up: Key Bindings
Changing Key Bindings Interactively
-----------------------------------
The way to redefine an Emacs key is to change 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.
`M-x global-set-key RET KEY CMD RET'
Define KEY globally to run CMD.
`M-x local-set-key RET KEY CMD RET'
Define KEY locally (in the major mode now in effect) to run CMD.
`M-x global-unset-key RET KEY'
Make KEY undefined in the global map.
`M-x local-unset-key RET KEY'
Make KEY undefined locally (in the major mode now in effect).
For example, suppose you like to execute commands in a subshell
within an Emacs buffer, instead of suspending Emacs and executing
commands in your login shell. Normally, `C-z' is bound to the function
`suspend-emacs', but you can change `C-z' to invoke an interactive
subshell within Emacs, by binding it to `shell' as follows:
M-x global-set-key RET C-z shell RET
`global-set-key' reads the command name after the key. After you
press the key, a message like this appears so that you can confirm that
you are binding the key you want:
Set key C-z to command:
You can redefine function keys and mouse events in the same way; just
type the function key or click the mouse when it's time to specify the
key to rebind.
You can rebind a key that contains more than one event in the same
way. Emacs keeps reading the key to rebind until it is a complete key
(that is, not a prefix key). Thus, if you type `C-f' for KEY, that's
the end; the minibuffer is entered immediately to read CMD. But if you
type `C-x', another character is read; if that is `4', another
character is read, and so on. For example,
M-x global-set-key RET C-x 4 $ spell-other-window RET
would redefine `C-x 4 $' to run the (fictitious) command
`spell-other-window'.
You can remove the global definition of a key with
`global-unset-key'. This makes the key "undefined"; if you type it,
Emacs will just beep. Similarly, `local-unset-key' makes a key
undefined in the current major mode keymap, which makes the global
definition (or lack of one) come back into effect in that major mode.
If you have redefined (or undefined) a key and you subsequently wish
to retract the change, undefining the key will not do the job--you need
to redefine the key with its standard definition. To find the name of
the standard definition of a key, go to a Fundamental mode buffer and
use `C-h c'. The documentation of keys in this manual also lists their
command names.
If you want to prevent yourself from invoking a command by mistake,
it is better to disable the command than to undefine the key. A
disabled command is less work to invoke when you really want to. *Note
Disabling::.
File: emacs, Node: Init Rebinding, Next: Function Keys, Prev: Rebinding, Up: Key Bindings
Rebinding Keys in Your Init File
--------------------------------
If you have a set of default definitions that you like to use all
the time, you can put commands in your `.emacs' file by using their
Lisp syntax. Thus, the first `global-set-key' command in this section
could be put in an `.emacs' file in either of the two following formats:
(global-set-key "\C-z" 'shell)
or as:
(global-set-key [?\C-z] 'shell)
When the key sequence consists of characters, like this one, you can
write it as a string or as a vector. The first format specifies the key
sequence as a string, `"\C-z"'. The second format uses a vector to
specify the key sequence. The square brackets (`[...]') delimit the
contents of the vector. The vector in this example contains just one
element, which is the integer code corresponding to `C-z'. The
question mark is the Lisp syntax for a character constant; the
character must follow with no intervening spaces.
The single-quote before `shell' marks it as a constant symbol rather
than a variable. If you omit the quote, Emacs tries to evaluate
`shell' immediately as a variable. This probably causes an error; it
certainly isn't what you want.
Here is another example that binds a key sequence two characters
long:
(global-set-key "\C-xl" 'make-symbolic-link)
or:
(global-set-key [?\C-x ?l] 'make-symbolic-link)
File: emacs, Node: Function Keys, Next: Mouse Buttons, Prev: Init Rebinding, Up: Key Bindings
Rebinding Function Keys
-----------------------
Key sequences can contain function keys as well as ordinary
characters. Just as Lisp characters (actually integers) represent
keyboard characters, Lisp symbols represent function keys. If the
function key has a word as its label, then that word is also the name
of the corresponding Lisp symbol. Here are the Lisp names for other
function keys:
`left', `up', `right', `down'
Cursor arrow keys.
`begin', `end', `home', `next', `prior'
Other cursor repositioning keys.
`select', `print', `execute', `backtab'
`insert', `undo', `redo', `clearline'
`insertline', `deleteline', `insertchar', `deletechar',
Miscellaneous function keys.
`f1' ... `f35'
Numbered function keys (across the top of the keyboard).
`kp-add', `kp-subtract', `kp-multiply', `kp-divide'
`kp-backtab', `kp-space', `kp-tab', `kp-enter'
`kp-separator', `kp-decimal', `kp-equal'
Keypad keys (to the right of the regular keyboard), with names or
punctuation.
`kp-0', `kp-1', ... `kp-9'
Keypad keys with digits.
`kp-f1', `kp-f2', `kp-f3', `kp-f4'
Keypad PF keys.
A key sequence which contains non-characters must be a vector rather
than a string. To write a vector, write square brackets containing the
vector elements. Write spaces to separate the elements. If an element
is a symbol, simply write the symbol's name--no delimiters or
punctuation are needed. If an element is a character, write a Lisp
character constant, which is `?' followed by the character as it would
appear in a string.
Thus, to bind function key `f1' to the command `rmail', write the
following:
(global-set-key [f1] 'rmail)
To bind the right-arrow key to the command `forward-char', you can
use this expression:
(global-set-key [right] 'forward-char)
using the Lisp syntax for a vector containing the symbol `right'.
(This binding is present in Emacs by default.)
You can mix function keys and characters in a key sequence. This
example binds `C-x RIGHT' to the command `forward-page'.
(global-set-key [?\C-x right] 'forward-page)
where `?\C-x' is the Lisp character constant for the character `C-x'.
The vector element `right' is a symbol and therefore does not take a
question mark.
You can use the modifier keys CTRL, META, HYPER, SUPER, ALT and
SHIFT with function keys. To represent these modifiers, prepend the
strings `C-', `M-', `H-', `s-', `A-' and `S-' to the symbol name.
Thus, here is how to make `Hyper-Meta-RIGHT' move forward a word:
(global-set-key [H-M-right] 'forward-word)
File: emacs, Node: Mouse Buttons, Next: Disabling, Prev: Function Keys, Up: Key Bindings
Rebinding Mouse Buttons
-----------------------
Emacs uses Lisp symbols to designate mouse buttons, too. The
ordinary mouse events in Emacs are "click" events; these happen when you
press a button and release it without moving the mouse. You can also
get "drag" events, when you move the mouse while holding the button
down. Drag events happen when you finally let go of the button.
The symbols for basic click events are `mouse-1' for the leftmost
button, `mouse-2' for the next, and so on. Here is how you can
redefine the second mouse button to split the current window:
(global-set-key [mouse-2] 'split-window-vertically)
The symbols for drag events are similar, but have the prefix `drag-'
before the word `mouse'. For example, dragging the left button
generates a `drag-mouse-1' event.
You can also request events when the mouse button is pressed down.
These events start with `down-' instead of `drag-'. Such events are
generated only if they have key bindings. When you get a button-down
event, a corresponding click or drag event will always follow.
The symbols for mouse events also indicate the status of the modifier
keys, with the usual prefixes `C-', `M-', `H-', `s-', `A-' and `S-'.
These always follow `drag-' or `down-'.
A frame includes areas that don't show text from the buffer, such as
the mode line and the scroll bar. You can tell whether a mouse button
comes from a special area of the screen by means of dummy "prefix
keys." For example, if you click the mouse in the mode line, you get
the prefix key `mode-line' before the ordinary mouse-button symbol.
Thus, here is how to define the command for clicking the left button in
a mode line to run `scroll-up':
(global-set-key [mode-line mouse-1] 'scroll-up)
Here is the complete list of these dummy prefix keys and their
meanings:
`mode-line'
The mouse was in the mode line of a window.
`vertical-line'
The mouse was in the vertical line separating side-by-side windows.
`vertical-scroll-bar'
The mouse was in a horizontal scroll bar. This is the kind of
scroll bar people normally use.
`horizontal-scroll-bar'
The mouse was in a horizontal scroll bar. Horizontal scroll bars
do horizontal scrolling, and people don't use them often.
You can put more than one mouse button in a key sequence, but it
isn't usual to do so.
File: emacs, Node: Disabling, Prev: Mouse Buttons, Up: Key Bindings
Disabling Commands
------------------
Disabling a command marks the command 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.
Attempting to invoke a disabled command interactively in Emacs
causes the display of a window containing the command's name, its
documentation, and some instructions on what to do immediately; 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.
The direct mechanism for disabling a command is to have a non-`nil'
`disabled' property on the Lisp symbol for the command. Here is the
Lisp program to do this:
(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 make a command disabled either by editing the `.emacs' file
directly or with the command `M-x disable-command', which edits the
`.emacs' file for you. Likewise, `M-x enable-command' edits `.emacs'
to enable a command permanently. *Note Init File::.
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.
File: emacs, Node: Keyboard Translations, Next: Syntax, Prev: Key Bindings, Up: Customization
Keyboard Translations
=====================
Some keyboards do not make it convenient to send all the special
characters that Emacs uses. The most common problem case is the DEL
character. Some keyboards provide no convenient way to type this very
important character--usually because they were designed to expect the
character `C-h' to be used for deletion. On these keyboard, if you
press the key normally used for deletion, Emacs handles the `C-h' as a
prefix character and offers you a list of help options, which is not
what you want.
You can work around this problem within Emacs by setting up keyboard
translations to turn `C-h' into DEL and DEL into `C-h', as follows:
;; Translate `C-h' to DEL.
(keyboard-translate ?\C-h ?\C-?)
;; Translate DEL to `C-h'.
(keyboard-translate ?\C-? ?\C-h)
Keyboard translations are not the same as key bindings in keymaps
(*note Keymaps::.). Emacs contains numerous keymaps that apply in
different situations, but there is only one set of keyboard
translations, and it applies to every character that Emacs reads from
the terminal. Keyboard translations take place at the lowest level of
input processing; the keys that are looked up in keymaps contain the
characters that result from keyboard translation.
For full information about how to use keyboard translations, see
*Note Translating Input: (elisp)Translating Input.
File: emacs, Node: Syntax, Next: Init File, Prev: Keyboard Translations, Up: Customization
The Syntax Table
================
All the Emacs commands which parse words or balance parentheses are
controlled by the "syntax table". The syntax table says which
characters are opening delimiters, which are parts of words, which are
string quotes, and so on. 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.
To display a description of the contents of the current syntax table,
type `C-h s' (`describe-syntax'). The description of each character
includes both the string you would have to give to
`modify-syntax-entry' to set up that character's current syntax, and
some English to explain that string if necessary.
For full information on the syntax table, see *Note Syntax Table:
(elisp)Syntax Table.
File: emacs, Node: Init File, Prev: Syntax, Up: Customization
The Init File, `~/.emacs'
=========================
When Emacs is started, it normally loads a Lisp program from the file
`.emacs' in your home directory. We call this file your "init file"
because it specifies how to initialize Emacs for you. You can use the
command line switches `-q' and `-u' to tell Emacs whether to load an
init file, and which one (*note Entering Emacs::.).
There can also be 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 (except when you specify `-q'). 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 such as `~/SOMETHING.el', byte-compile it,
and make your `.emacs' file load it with `(load "~/SOMETHING")'. *Note
Byte Compilation: (elisp)Byte Compilation, for more information about
compiling Emacs Lisp programs.
* Menu:
* Init Syntax:: Syntax of constants in Emacs Lisp.
* Init Examples:: How to do some things with an init file.
* Terminal Init:: Each terminal type can have an init file.
* Find Init:: How Emacs finds the init file.
File: emacs, Node: Init Syntax, Next: Init Examples, Up: Init File
Init File Syntax
----------------
The `.emacs' file contains one or more Lisp function call
expressions. Each of these consists of a function name followed by
arguments, all surrounded by parentheses. For example, `(setq
fill-column 60)' calls the function `setq' to set the variable
`fill-column' (*note Filling::.) 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:
Numbers:
Numbers are written in decimal, with an optional initial minus
sign.
Strings:
Lisp string syntax is the same as C string syntax with a few extra
features. Use a double-quote character to begin and end a string
constant.
In a string, you can include newlines and special characters
literally. But often it is cleaner to use backslash sequences for
them: `\n' for newline, `\b' for backspace, `\r' for carriage
return, `\t' for tab, `\f' for formfeed (control-L), `\e' for
escape, `\\' for a backslash, `\"' for a double-quote, or `\OOO'
for the character whose octal code is OOO. Backslash and
double-quote are the only characters for which backslash sequences
are mandatory.
`\C-' can be used as a prefix for a control character, as in
`\C-s' for ASCII control-S, and `\M-' can be used as a prefix for
a Meta character, as in `\M-a' for `Meta-A' or `\M-\C-a' for
`Control-Meta-A'.
Characters:
Lisp character constant syntax consists of a `?' followed by
either a character or an escape sequence starting with `\'.
Examples: `?x', `?\n', `?\"', `?\)'. Note that strings and
characters are not interchangeable in Lisp; some contexts require
one and some contexts require the other.
True:
`t' stands for `true'.
False:
`nil' stands for `false'.
Other Lisp objects:
Write a single-quote (') followed by the Lisp object you want.
File: emacs, Node: Init Examples, Next: Terminal Init, Prev: Init Syntax, Up: Init File
Init File Examples
------------------
Here are some examples of doing certain commonly desired things with
Lisp expressions:
* Make TAB in C mode just insert a tab if point is in the middle of a
line.
(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'.
* Make searches case sensitive by default (in all buffers that do not
override this).
(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 not what you probably want to do in an init
file.
* Make Text mode the default mode for new buffers.
(setq default-major-mode 'text-mode)
Note that `text-mode' is used because it is the command for
entering Text mode. The single-quote before it makes the symbol a
constant; otherwise, `text-mode' would be treated as a variable
name.
* Turn on Auto Fill mode automatically in Text mode and related
modes.
(add-hook 'text-mode-hook
'(lambda () (auto-fill-mode 1)))
This shows how to add a hook function to a normal hook variable
(*note Hooks::.). The function we supply is a list starting with
`lambda', with a single-quote in front of it to make it a list
constant rather than an expression.
It's beyond the scope of this manual to explain Lisp functions,
but for this example it is enough to know that the effect is to
execute `(auto-fill-mode 1)' when Text mode is entered. You can
replace it with any other expression that you like, or with
several expressions in a row.
Emacs comes with a function named `turn-on-auto-fill' whose
definition is `(lambda () (auto-fill-mode 1))'. Thus, a simpler
way to write the above example is as follows:
(add-hook 'text-mode-hook 'turn-on-auto-fill)
* Load the installed Lisp library named `foo' (actually a file
`foo.elc' or `foo.el' in a standard Emacs directory).
(load "foo")
When the argument to `load' is a relative file name, not starting
with `/' or `~', `load' searches the directories in `load-path'
(*note Lisp Libraries::.).
* Load the compiled Lisp file `foo.elc' from your home directory.
(load "~/foo.elc")
Here an absolute file name is used, so no searching is done.
* Rebind the key `C-x l' to run the function `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.
* Do the same thing for C mode only.
(define-key c-mode-map "\C-xl" 'make-symbolic-link)
* Redefine all keys which now run `next-line' in Fundamental mode so
that they run `forward-line' instead.
(substitute-key-definition 'next-line 'forward-line
global-map)
* Make `C-x C-v' undefined.
(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' will make `C-x C-v' a prefix,
but `C-x C-v' must first be freed of its usual non-prefix
definition.
* Make `$' have the syntax of punctuation in Text mode. Note the
use of a character constant for `$'.
(modify-syntax-entry ?\$ "." text-mode-syntax-table)
* Enable the use of the command `eval-expression' without
confirmation.
(put 'eval-expression 'disabled nil)
File: emacs, Node: Terminal Init, Next: Find Init, Prev: Init Examples, Up: Init File
Terminal-specific Initialization
--------------------------------
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'.
Emacs runs the hook `term-setup-hook' at the end of initialization,
after both your `.emacs' file and any terminal-specific library have
been read in. Add hook functions to this hook if you wish to override
part of any of the terminal-specific libraries and to define
initializations for terminals that do not have a library. *Note
Hooks::.
File: emacs, Node: Find Init, Prev: Terminal Init, Up: Init File
How Emacs Finds Your Init File
------------------------------
Normally Emacs uses the environment variable `HOME' to find
`.emacs'; that's what `~' means in a file name. But if you have done
`su', Emacs tries to find your own `.emacs', not that of the user you
are currently pretending to be. The idea is that you should get your
own editor customizations even if you are running as the super user.
More precisely, Emacs first determines which user's init file to use.
It gets the user name from the environment variables `USER' and
`LOGNAME'; if neither of those exists, it uses effective user-ID. If
that user name matches the real user-ID, then Emacs uses `HOME';
otherwise, it looks up the home directory corresponding to that user
name in the system's data base of users.
File: emacs, Node: Quitting, Next: Lossage, Prev: Customization, Up: Top
Quitting and Aborting
=====================
`C-g'
Quit. Cancel running or partially typed command.
`C-]'
Abort innermost recursive editing level and cancel the command
which invoked it (`abort-recursive-edit').
`M-x top-level'
Abort all recursive editing levels that are currently executing.
`C-x u'
Cancel an already-executed command, usually (`undo').
There are two ways of cancelling commands which are not finished
executing: "quitting" with `C-g', and "aborting" with `C-]' or `M-x
top-level'. Quitting cancels a partially typed command or one which is
already running. Aborting exits a recursive editing level and cancels
the command that invoked the recursive edit. (*Note Recursive Edit::.)
Quitting with `C-g' is used for getting rid of a partially typed
command, or a numeric argument that you don't want. It also stops a
running command in the middle in a relatively safe way, so you can use
it if you accidentally give a command which takes a long time. In
particular, it is safe to quit out of killing; either your text will
*all* still be in the buffer, or it will *all* be in the kill ring (or
maybe both). Quitting an incremental search does special things
documented under searching; in general, it may take two successive
`C-g' characters to get out of a search.
`C-g' works by setting the variable `quit-flag' to `t' the instant
`C-g' is typed; Emacs Lisp checks this variable frequently and quits if
it is non-`nil'. `C-g' is only actually executed as a command if you
type it while Emacs is waiting for input.
If you quit with `C-g' a second time before the first `C-g' is
recognized, you activate the "emergency escape" feature and return to
the shell. *Note Emergency Escape::.
There may be times when you cannot quit. When Emacs is waiting for
the operating system to do something, quitting is impossible unless
special pains are taken for the particular system call within Emacs
where the waiting occurs. We have done this for the system calls that
users are likely to want to quit from, but it's possible you will find
another. In one very common case--waiting for file input or output
using NFS--Emacs itself knows how to quit, but most NFS implementations
simply do not allow user programs to stop waiting for NFS when the NFS
server is hung.
Aborting with `C-]' (`abort-recursive-edit') is used to get out of a
recursive editing level and cancel the command which invoked it.
Quitting with `C-g' does not do this, and could not do this, because it
is used to cancel a partially typed command *within* the recursive
editing level. Both operations are useful. For example, if you are in
a recursive edit and type `C-u 8' to enter a numeric argument, you can
cancel that argument with `C-g' and remain in the recursive edit.
The command `M-x top-level' is equivalent to "enough" `C-]' commands
to get you out of all the levels of recursive edits that you are in.
`C-]' gets you out one level at a time, but `M-x top-level' goes out
all levels at once. Both `C-]' and `M-x top-level' are like all other
commands, and unlike `C-g', in that they are effective only when Emacs
is ready for a command. `C-]' is an ordinary key and has its meaning
only because of its binding in the keymap. *Note Recursive Edit::.
`C-x u' (`undo') is not strictly speaking a way of cancelling a
command, but you can think of it as cancelling a command already
finished executing. *Note Undo::.