Customization
*************

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 Init File.

Minor Modes
===========

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 Filling.

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 Abbrevs, for full information.

Variables
=========

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 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 Filling).

Examining and Setting Variables
-------------------------------

C-h v
M-x describe-variable
     Print the value and documentation of a variable.

M-x set-variable
     Change the value of a variable.

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.

Easy Customization Interface
----------------------------

A convenient way to find the user option variables that you want to change, and then change them, is with M-x customize.  This command creates a customization buffer with which you can browse through the Emacs user options in a logically organized structure, then edit and set their values.  You can also use the customization buffer to save settings permanently.  (Not all Emacs user options are included in this structure as of yet, but we are adding the rest.)

Customization Groups
....................

For customization purposes, user options are organized into groups to help you find them.  Groups are collected into bigger groups, all the way up to a master group called Emacs.

M-x customize creates a customization buffer that shows the top-level Emacs group and the second-level groups immediately under it.  It looks like this, in part:

     /- Emacs group: ---------------------------------------------------\
           [State]: visible group members are all at standard settings.
        Customization of the One True Editor.
        See also [Manual].

      [Open] Editing group
     Basic text editing facilities.

      [Open] External group
     Interfacing to external utilities.

     MORE SECOND-LEVEL GROUPS

     \- Emacs group end ------------------------------------------------/

This says that the buffer displays the contents of the Emacs group.  The other groups are listed because they are its contents.  But they are listed differently, without indentation and dashes, because their contents are not included.  Each group has a single-line documentation string; the Emacs group also has a [State] line.

Most of the text in the customization buffer is read-only, but it typically includes some editable fields that you can edit.  There are also active fields; this means a field that does something when you invoke it.  To invoke an active field, either click on it with Mouse-1, or move point to it and type RET.

For example, the phrase [Open] that appears in a second-level group is an active field.  Invoking the [Open] field for a group opens up a new customization buffer, which shows that group and its contents.  This field is a kind of hypertext link to another group.

The Emacs group does not include any user options itself, but other groups do.  By examining various groups, you will eventually find the options and faces that belong to the feature you are interested in customizing.  Then you can use the customization buffer to set them.

You can view the structure of customization groups on a larger scale with M-x customize-browse.  This command creates a special kind of customization buffer which shows only the names of the groups (and options and faces), and their structure.

In this buffer, you can show the contents of a group by invoking [+].  When the group contents are visible, this button changes to [-]; invoking that hides the group contents.

Each group, option or face name in this buffer has an active field which says [Group], [Option] or [Face].  Invoking that active field creates an ordinary customization buffer showing just that group and its contents, just that option, or just that face. This is the way to set values in it.

Changing an Option
..................

Here is an example of what a user option looks like in the customization buffer:

     Kill Ring Max: [Hide] 30
        [State]: this option is unchanged from its standard setting.
     Maximum length of kill ring before oldest elements are thrown away.

The text following [Hide], 30 in this case, indicates the current value of the option.  If you see [Show] instead of [Hide], it means that the value is hidden; the customization buffer initially hides values that take up several lines.  Invoke [Show] to show the value.

The line after the option name indicates the customization state of the option: in the example above, it says you have not changed the option yet.  The word [State] at the beginning of this line is active; you can get a menu of various operations by invoking it with Mouse-1 or RET.  These operations are essential for customizing the variable.

The line after the [State] line displays the beginning of the option's documentation string.  If there are more lines of documentation, this line ends with [More]; invoke this to show the full documentation string.

To enter a new value for Kill Ring Max, move point to the value and edit it textually.  For example, you can type M-d, then insert another number.

When you begin to alter the text, you will see the [State] line change to say that you have edited the value:

     [State]: you have edited the value as text, but not set the option.

Editing the value does not actually set the option variable.  To do that, you must set the option.  To do this, invoke the word [State] and choose Set for Current Session.

The state of the option changes visibly when you set it:

     [State]: you have set this option, but not saved it for future sessions.

You don't have to worry about specifying a value that is not valid; setting the option checks for validity and will not really install an unacceptable value.

While editing a value or field that is a file name, directory name, command name, or anything else for which completion is defined, you can type M-TAB (widget-complete) to do completion.

Some options have a small fixed set of possible legitimate values. These options don't let you edit the value textually.  Instead, an active field [Value Menu] appears before the value; invoke this field to edit the value.  For a boolean ``on or off'' value, the active field says [Toggle], and it changes to the other value. [Value Menu] and [Toggle] edit the buffer; the changes take effect when you use the Set for Current Session operation.

Some options have values with complex structure.  For example, the value of load-path is a list of directories.  Here is how it appears in the customization buffer:

     Load Path:
     [INS] [DEL] [Current dir?]: /usr/local/share/emacs/19.34.94/site-lisp
     [INS] [DEL] [Current dir?]: /usr/local/share/emacs/site-lisp
     [INS] [DEL] [Current dir?]: /usr/local/share/emacs/19.34.94/leim
     [INS] [DEL] [Current dir?]: /usr/local/share/emacs/19.34.94/lisp
     [INS] [DEL] [Current dir?]: /build/emacs/e19/lisp
     [INS] [DEL] [Current dir?]: /build/emacs/e19/lisp/gnus
     [INS]
        [State]: this item has been changed outside the customization buffer.
     List of directories to search for files to load....

Each directory in the list appears on a separate line, and each line has several editable or active fields.

You can edit any of the directory names.  To delete a directory from the list, invoke [DEL] on that line.  To insert a new directory in the list, invoke [INS] at the point where you want to insert it.

You can also invoke [Current dir?] to switch between including a specific named directory in the path, and including nil in the path.  (nil in a search path means ``try the current directory.'')

Two special commands, TAB and S-TAB, are useful for moving through the customization buffer.  TAB (widget-forward) moves forward to the next active or editable field; S-TAB (widget-backward) moves backward to the previous active or editable field.

Typing RET on an editable field also moves forward, just like TAB.  The reason for this is that people have a tendency to type RET when they are finished editing a field.  If you have occasion to insert a newline in an editable field, use C-o or C-q C-j,

Setting the option changes its value in the current Emacs session; saving the value changes it for future sessions as well.  This works by writing code into your ~/.emacs file so as to set the option variable again each time you start Emacs.  To save the option, invoke [State] and select the Save for Future Sessions operation.

You can also restore the option to its standard value by invoking [State] and selecting the Reset operation.  There are actually three reset operations:

Reset to Current
     If you have made some modifications and not yet set the option, this restores the text in the customization buffer to match the actual value.

Reset to Saved
     This restores the value of the option to the last saved value, and updates the text accordingly.

Reset to Standard Settings
     This sets the option to its standard value, and updates the text accordingly.  This also eliminates any saved value for the option, so that you will get the standard value in future Emacs sessions.

The state of a group indicates whether anything in that group has been edited, set or saved.  You can select Set for Current Session, Save for Future Sessions and the various kinds of Reset operation for the group; these operations on the group apply to all options in the group and its subgroups.

Near the top of the customization buffer there are two lines containing several active fields:

      [Set] [Save] [Reset]  [Done]

Invoking [Done] buries this customization buffer.  Each of the other fields performs an operation---set, save or reset---on each of the items in the buffer that could meaningfully be set, saved or reset.

Customizing Faces
.................

In addition to user options, some customization groups also include faces.  When you show the contents of a group, both the user options and the faces in the group appear in the customization buffer.  Here is an example of how a face looks:

     Custom Changed Face: (sample)
        [State]: this face is unchanged from its standard setting.
     Face used when the customize item has been changed.
     Parent groups: [Custom Magic Faces]
     Attributes: [ ] Bold: [Toggle]  off (nil)
                 [ ] Italic: [Toggle]  off (nil)
                 [ ] Underline: [Toggle]  off (nil)
                 [ ] Foreground: white       (sample)
                 [ ] Background: blue        (sample)
                 [ ] Inverse: [Toggle]  off (nil)
                 [ ] Stipple:
                 [ ] Font Family:
                 [ ] Size:
                 [ ] Strikethru: off

Each face attribute has its own line.  The [X] field before the attribute name indicates whether the attribute is enabled; X means that it is.  You can enable or disable the attribute by invoking that field.  When the attribute is enabled, you can change the attribute value in the usual ways.

Setting, saving and resetting a face work like the same operations for options (see Changing an Option).

A face can specify different appearances for different types of display.  For example, a face can make text red on a color display, but use a bold font on a monochrome display.  To specify multiple appearances for a face, select Show Display Types in the menu you get from invoking [State].

Customizing Specific Items
..........................

Instead of finding the options you want to change by moving down through the structure of groups, you can specify the particular option, face or group that you want to customize.

M-x customize-option RET OPTION RET
     Set up a customization buffer with just one option, OPTION.

M-x customize-face RET FACE RET
     Set up a customization buffer with just one face, FACE.

M-x customize-group RET GROUP RET
     Set up a customization buffer with just one group, GROUP.

M-x customize-apropos RET REGEXP RET
     Set up a customization buffer with all the options, faces and groups that match REGEXP.

M-x customize-saved
     Set up a customization buffer containing all options and faces that you have saved with customization buffers.

M-x customize-customized
     Set up a customization buffer containing all options and faces that you have customized but not saved.

If you want to alter a particular user option variable with the customization buffer, and you know its name, you can use the command M-x customize-option and specify the option name.  This sets up the customization buffer with just one option---the one that you asked for.  Editing, setting and saving the value work as described above, but only for the specified option.

Likewise, you can modify a specific face, chosen by name, using M-x customize-face.

You can also set up the customization buffer with a specific group, using M-x customize-group.  The immediate contents of the chosen group, including option variables, faces, and other groups, all appear as well.  However, these subgroups' own contents start out hidden.  You can show their contents in the usual way, by invoking [Show].

To control more precisely what to customize, you can use M-x customize-apropos.  You specify a regular expression as argument; then all options, faces and groups whose names match this regular expression are set up in the customization buffer.  If you specify an empty regular expression, this includes all groups, options and faces in the customization buffer (but that takes a long time).

If you change option values and then decide the change was a mistake, you can use two special commands to revisit your previous changes.  Use customize-saved to look at the options and faces that you have saved.  Use M-x customize-customized to look at the options and faces that you have set but not saved.

Editing Variable Values
-----------------------

M-x list-options
     Display a buffer listing names, values, and documentation of all options.

M-x edit-options
     Change option values by editing a list of options.

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:

s
     Set the variable point is in or near to a new value read using the minibuffer.

x
     Toggle the variable point is in or near: if the value was nil, it becomes t; otherwise it becomes nil.

1
     Set the variable point is in or near to t.

0
     Set the variable point is in or near to nil.

n
p
     Move to the next or previous variable.

Local Variables
---------------

M-x make-local-variable
     Make a variable have a local value in the current buffer.

M-x kill-local-variable
     Make a variable use its global value in the current buffer.

M-x make-variable-buffer-local
     Mark a variable so that setting it will make it local to the buffer that is current at that time.

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)

Local Variables in Files
------------------------

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 Init File).  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 occurrences of `-*-', XEmacs 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.

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 invoke 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 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.

Basic Use
---------

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.

Naming and Saving Keyboard Macros
---------------------------------

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 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 Lisp Libraries).  If the file you save in is your initialization file ~/.emacs (see Init File), 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.

Executing Macros With Variations
--------------------------------

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 Recursive Edit.

Customizing Key Bindings
========================

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.

Keymaps
-------

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.

Changing Key Bindings
---------------------

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.

Changing Key Bindings Interactively
...................................

M-x global-set-key RET KEY CMD RET
     Defines KEY globally to run CMD.

M-x local-set-key RET KEYS CMD RET
     Defines KEY locally (in the major mode now in effect) to run CMD.

M-x local-unset-key RET KEYS RET
     Removes the local binding of KEY.

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 Init File, 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.

Changing Key Bindings Programmatically
......................................

You can use the functions global-set-key and define-key to rebind keys under program control.

(global-set-key KEYS CMD)
     Defines KEYS globally to run CMD.

(define-key KEYMAP KEYS DEF)
     Defines KEYS to run DEF in the keymap KEYMAP.

KEYMAP is a keymap object.

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

  * A command, that is, a Lisp function suitable for interactive calling

  * A string or key sequence vector, which is treated as a keyboard macro

  * A keymap to define a prefix key

  * A symbol so that when the key is looked up, the symbol stands for its function definition, which should at that time be one of the above, or another symbol whose function definition is used, and so on

  * A cons, (string . defn), meaning that DEFN is the definition (DEFN should be a valid definition in its own right)

  * A cons, (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 Keystrokes, 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:

  * The keysym by itself is equivalent to a list of just that keysym, i.e., f1 is equivalent to (f1).

  * A keystroke by itself is equivalent to a vector containing just that keystroke, i.e.,  (control a) is equivalent to [(control a)].

  * You can use ASCII codes for keysyms that have them. i.e., 65 is equivalent to A. (This is not so much an abbreviation as an alternate representation.)

Here are some examples of programmatically binding keys:

     ;;;  Bind my-command to f1
     (global-set-key 'f1 'my-command)

     ;;;  Bind my-command to Shift-f1
     (global-set-key '(shift f1) 'my-command)

     ;;; Bind my-command to C-c Shift-f1
     (global-set-key '[(control c) (shift f1)] 'my-command)

     ;;; Bind my-command to the middle mouse button.
     (global-set-key 'button2 'my-command)

     ;;; Bind my-command to META CTL Right Mouse Button
     ;;; in the keymap that is in force when you are running dired.
     (define-key dired-mode-map '(meta control button3) 'my-command)

Using Strings for Changing Key Bindings
.......................................

For backward compatibility, you can still use strings to represent key sequences.  Thus you can use commands 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 Commands
------------------

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 Init File.

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.

The Syntax Table
================

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.

Information About Each Character
--------------------------------

The syntax table entry for a character is a number that encodes six pieces of information:

  * The syntactic class of the character, represented as a small integer

  * The matching delimiter, for delimiter characters only (the matching delimiter of ( is ), and vice versa)

  * A flag saying whether the character is the first character of a two-character comment starting sequence

  * A flag saying whether the character is the second character of a two-character comment starting sequence

  * A flag saying whether the character is the first character of a two-character comment ending sequence

  * A flag saying whether the character is the second character of a two-character comment ending sequence

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 class of whitespace characters.

w
     The class of word-constituent characters.

_
     The class of characters that are part of symbol names but not words. This class is represented by _ because the character _ has this class in both C and Lisp.

.
     The class of punctuation characters that do not fit into any other special class.

(
     The class of opening delimiters.

)
     The class of closing delimiters.

'
     The class of expression-adhering characters.  These characters are part of a symbol if found within or adjacent to one, and are part of a following expression if immediately preceding one, but are like whitespace if surrounded by whitespace.

"
     The class of string-quote characters.  They match each other in pairs, and the characters within the pair all lose their syntactic significance except for the \ and / classes of escape characters, which can be used to include a string-quote inside the string.

$
     The class of self-matching delimiters.  This is intended for TeX's $, which is used both to enter and leave math mode.  Thus, a pair of matching $ characters surround each piece of math mode TeX input.  A pair of adjacent $ characters act like a single one for purposes of matching.

/
     The class of escape characters that always just deny the following character its special syntactic significance.  The character after one of these escapes is always treated as alphabetic.

\
     The class of C-style escape characters.  In practice, these are treated just like /-class characters, because the extra possibilities for C escapes (such as being followed by digits) have no effect on where the containing expression ends.

<
     The class of comment-starting characters.  Only single-character comment starters (such as ; in Lisp mode) are represented this way.

>
     The class of comment-ending characters.  Newline has this syntax in Lisp mode.

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.

Altering Syntax Information
---------------------------

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.

 1. The first character in the string specifies the syntactic class.  It is one of the characters in the previous table (see Syntax Entry).

 2. The second character is the matching delimiter.  For a character that is not an opening or closing delimiter, this should be a space, and may be omitted if no following characters are needed.

 3. The remaining characters are flags.  The flag characters allowed are:

     1
          Flag this character as the first of a two-character comment starting sequence.

     2
          Flag this character as the second of a two-character comment starting sequence.

     3
          Flag this character as the first of a two-character comment ending sequence.

     4
          Flag this character as the second of a two-character comment ending sequence.

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.

The Init File, .emacs
=====================

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 Entering 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 Lisp Libraries), and load that file from your .emacs file using load.

Init File Syntax
----------------

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 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
     Integers are written in decimal, with an optional initial minus sign.

     If a sequence of digits is followed by a period and another sequence of digits, it is interpreted as a floating point number.

     The number prefixes #b, #o, and #x are supported to represent numbers in binary, octal, and hexadecimal notation (or radix).

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.

     Newlines and special characters may be present literally in strings.  They can also be represented as backslash sequences: \n for newline, \b for backspace, \r for 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.

     You can use \C- as a prefix for a control character, as in \C-s for ASCII Control-S, and \M- 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.

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 probably not what you 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 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.

  * Turn on Auto Fill mode automatically in Text mode and related modes.

          (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 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 pathname, not starting with / or ~, load searches the directories in load-path (see Loading).

  * 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)

  * Bind the function key F1 to a command in C mode. Note that the names of function keys must be lower case.

          (define-key c-mode-map 'f1 'make-symbolic-link)

  * Bind the shifted version of F1 to a command.

          (define-key c-mode-map '(shift f1) 'make-symbolic-link)

  * Redefine all keys which now run next-line in Fundamental mode to 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 would make C-x C-v a prefix, but C-x C-v must be freed of any non-prefix definition first.

  * 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)

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.

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.

Changing the Bell Sound
=======================

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
     A string of raw sound data, or the name of another sound to play. The symbol t here means use the default X beep.

volume
     An integer from 0-100, defaulting to bell-volume.

pitch
     If using the default X beep, the pitch (Hz) to generate.

duration
     If using the default X beep, the duration (milliseconds).

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
     An auto-save does not succeed

command-error
     The Emacs command loop catches an error

undefined-key
     You type a key that is undefined

undefined-click
     You use an undefined mouse-click combination

no-completion
     Completion was not possible

y-or-n-p
     You type something other than the required y or n

yes-or-no-p
     You type something other than yes or no

Faces
=====

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.

Customizing Faces
-----------------

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.

M-x invert-face
     Swap the foreground and background colors of the given FACE.

M-x make-face-bold
     Make the font of the given FACE bold.  When called from a program, returns nil if this is not possible.

M-x make-face-bold-italic
     Make the font of the given FACE bold italic. When called from a program, returns nil if not possible.

M-x make-face-italic
     Make the font of the given FACE italic. When called from a program, returns nil if not possible.

M-x make-face-unbold
     Make the font of the given FACE non-bold. When called from a program, returns nil if not possible.

M-x make-face-unitalic
     Make the font of the given FACE non-italic. When called from a program, returns nil if not possible.

M-x make-face-larger
     Make the font of the given FACE a little larger. When called from a program, returns nil if not possible.

M-x make-face-smaller
     Make the font of the given FACE a little smaller. When called from a program, returns nil if not possible.

M-x set-face-background
     Change the background color of the given FACE.

M-x set-face-background-pixmap
     Change the background pixmap of the given FACE.

M-x set-face-font
     Change the font of the given FACE.

M-x set-face-foreground
     Change the foreground color of the given FACE.

M-x set-face-underline-p
     Change whether the given FACE is underlined.

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.

X Resources
===========

Historically, XEmacs has used the X resource application class Emacs for its resources.  Unfortunately, GNU Emacs uses the same application class, and resources are not compatible between the two Emacsen.  This sharing of the application class often leads to trouble if you want to run both variants.

Starting with XEmacs 21, XEmacs uses the class XEmacs if it finds any XEmacs resources in the resource database when the X connection is initialized.  Otherwise, it will use the class Emacs for backwards compatability.  The variable X-EMACS-APPLICATION-CLASS may be consulted to determine the application class being used.

The examples in this section assume the application class is Emacs.

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

Geometry Resources
------------------

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

  * The -geometry command-line option sets the Emacs.geometry resource, that is, the geometry of the ApplicationShell.

  * For the first frame created, the size of the frame is taken from the ApplicationShell if it is specified, otherwise from the geometry of the frame.

  * For subsequent frames, the order is reversed: First the frame, and then the ApplicationShell.

  * For the first frame created, the position of the frame is taken from the ApplicationShell (Emacs.geometry) if it is specified, otherwise from the geometry of the frame.

  * For subsequent frames, the position is taken only from the frame, and never from the ApplicationShell.

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.

Iconic Resources
----------------

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.

Resource List
-------------

Emacs frames accept the following resources:

geometry (class Geometry): string
     Initial geometry for the frame.  See Geometry Resources for a complete discussion of how this works.

iconic (class Iconic): boolean
     Whether this frame should appear in the iconified state.

internalBorderWidth (class InternalBorderWidth): int
     How many blank pixels to leave between the text and the edge of the window.

interline (class Interline): int
     How many pixels to leave between each line (may not be implemented).

menubar (class Menubar): boolean
     Whether newly-created frames should initially have a menubar.  Set to true by default.

initiallyUnmapped (class InitiallyUnmapped): boolean
     Whether XEmacs should leave the initial frame unmapped when it starts up.  This is useful if you are starting XEmacs as a server (e.g. in conjunction with gnuserv or the external client widget).  You can also control this with the -unmapped command-line option.

barCursor (class BarColor): boolean
     Whether the cursor should be displayed as a bar, or the traditional box.

cursorColor (class CursorColor): color-name
     The color of the text cursor.

scrollBarWidth (class ScrollBarWidth): integer
     How wide the vertical scrollbars should be, in pixels; 0 means no vertical scrollbars.  You can also use a resource specification of the form *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
     How high the horizontal scrollbars should be, in pixels; 0 means no horizontal scrollbars.  You can also use a resource specification of the form *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
     Where the horizontal and vertical scrollbars should be positioned.  This should be one of the four strings BOTTOM_LEFT, BOTTOM_RIGHT, TOP_LEFT, and TOP_RIGHT.  Default is BOTTOM_RIGHT for the Motif and Lucid scrollbars and BOTTOM_LEFT for the Athena scrollbars.

topToolBarHeight (class TopToolBarHeight): integer
bottomToolBarHeight (class BottomToolBarHeight): integer
leftToolBarWidth (class LeftToolBarWidth): integer
rightToolBarWidth (class RightToolBarWidth): integer
     Height and width of the four possible toolbars.

topToolBarShadowColor (class TopToolBarShadowColor): color-name
bottomToolBarShadowColor (class BottomToolBarShadowColor): color-name
     Color of the top and bottom shadows for the toolbars.  NOTE: These resources do not have anything to do with the top and bottom toolbars (i.e. the toolbars at the top and bottom of the frame)!  Rather, they affect the top and bottom shadows around the edges of all four kinds of toolbars.

topToolBarShadowPixmap (class TopToolBarShadowPixmap): pixmap-name
bottomToolBarShadowPixmap (class BottomToolBarShadowPixmap): pixmap-name
     Pixmap of the top and bottom shadows for the toolbars.  If set, these resources override the corresponding color resources. NOTE: These resources do not have anything to do with the top and bottom toolbars (i.e. the toolbars at the top and bottom of the frame)! Rather, they affect the top and bottom shadows around the edges of all four kinds of toolbars.

toolBarShadowThickness (class ToolBarShadowThickness): integer
     Thickness of the shadows around the toolbars, in pixels.

visualBell (class VisualBell): boolean
     Whether XEmacs should flash the screen rather than making an audible beep.

bellVolume (class BellVolume): integer
     Volume of the audible beep.

useBackingStore (class UseBackingStore): boolean
     Whether XEmacs should set the backing-store attribute of the X windows it creates.  This increases the memory usage of the X server but decreases the amount of X traffic necessary to update the screen, and is useful when the connection to the X server goes over a low-bandwidth line such as a modem connection.

Emacs devices accept the following resources:

textPointer (class Cursor): cursor-name
     The cursor to use when the mouse is over text.  This resource is used to initialize the variable x-pointer-shape.

selectionPointer (class Cursor): cursor-name
     The cursor to use when the mouse is over a selectable text region (an extent with the highlight property; for example, an Info cross-reference).  This resource is used to initialize the variable x-selection-pointer-shape.

spacePointer (class Cursor): cursor-name
     The cursor to use when the mouse is over a blank space in a buffer (that is, after the end of a line or after the end-of-file).  This resource is used to initialize the variable x-nontext-pointer-shape.

modeLinePointer (class Cursor): cursor-name
     The cursor to use when the mouse is over a modeline.  This resource is used to initialize the variable x-mode-pointer-shape.

gcPointer (class Cursor): cursor-name
     The cursor to display when a garbage-collection is in progress.  This resource is used to initialize the variable x-gc-pointer-shape.

scrollbarPointer (class Cursor): cursor-name
     The cursor to use when the mouse is over the scrollbar.  This resource is used to initialize the variable x-scrollbar-pointer-shape.

pointerColor (class Foreground): color-name
pointerBackground (class Background): color-name
     The foreground and background colors of the mouse cursor.  These resources are used to initialize the variables x-pointer-foreground-color and x-pointer-background-color.

Face Resources
--------------

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
     The font of this face.

attributeForeground (class AttributeForeground): color-name
attributeBackground (class AttributeBackground): color-name
     The foreground and background colors of this face.

attributeBackgroundPixmap (class AttributeBackgroundPixmap): file-name
     The name of an XBM file (or XPM file, if your version of Emacs supports XPM), to use as a background stipple.

attributeUnderline (class AttributeUnderline): boolean
     Whether text in this face should be underlined.

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
     Everything inherits from this.

bold
     If this is not specified in the resource database, Emacs tries to find a bold version of the font of the default face.

italic
     If this is not specified in the resource database, Emacs tries to find an italic version of the font of the default face.

bold-italic
     If this is not specified in the resource database, Emacs tries to find a bold-italic version of the font of the default face.

modeline
     This is the face that the modeline is displayed in.  If not specified in the resource database, it is determined from the default face by reversing the foreground and background colors.

highlight
     This is the face that highlighted extents (for example, Info cross-references and possible completions, when the mouse passes over them) are displayed in.

left-margin
right-margin
     These are the faces that the left and right annotation margins are displayed in.

zmacs-region
     This is the face that mouse selections are displayed in.

isearch
     This is the face that the matched text being searched for is displayed in.

info-node
     This is the face of info menu items.  If unspecified, it is copied from bold-italic.

info-xref
     This is the face of info cross-references.  If unspecified, it is copied from 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).

Widgets
-------

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.

Menubar Resources
-----------------

As the menubar is implemented as a widget which is not a part of XEmacs 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.