
@c FIXME -- we demand a detail menu!

@node Customization, Quitting, Emulation, Top
@chapter Customization
@cindex 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 init file or other appropriate
file to do the customization in each session.  @xref{Init File}.

@menu
* Minor Modes::     Each minor mode is one feature you can turn on
                     independently of any others.
* Behaviors::       Like minor modes, behaviors are independent of other
                     features, but behaviors are usually enabled globally,
                     while minor modes are per-buffer and often temporary.
* Variables::       Many Emacs commands examine Emacs variables
                     to decide what to do; by setting variables,
                     you can control their functioning.
* Keyboard Macros:: A keyboard macro records a sequence of keystrokes
                     to be replayed with a single command.
* Key Bindings::    The keymaps say what command each key runs.
                     By changing them, you can "redefine keys".
* Syntax::          The syntax table controls how words and expressions
                     are parsed.
* Init File::       How to write common customizations in the init file.
* Audible Bell::    Changing how Emacs sounds the bell.
* Faces::           Changing the fonts and colors of a region of text.
* Frame Components::  Controlling the presence and positions of the
                     menubar, toolbars, and gutters.
* X Resources::     X resources controlling various aspects of the
                     behavior of XEmacs.
@end menu

@node Minor Modes, Behaviors, Customization, Customization
@section Minor Modes
@cindex minor modes

@cindex mode line
  Minor modes are common options which may be useful in many major
modes, but which may need to be enabled or disabled independently of the
major mode.  (This may be because user preferences for the feature vary,
or because the feature is sometimes more of a hindrance than an aid
depending on the specific content of the buffer.)  For example, Auto
Fill mode is a minor mode in which @key{SPC} automatically breaks lines
between words at the right margin
as you type.  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, @samp{Fill} in the mode line means that
Auto Fill mode is on.

  Append @code{-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 @kbd{M-x auto-fill-mode}.  These
commands are usually invoked with @kbd{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 called @dfn{toggling}.  A positive
argument always turns the mode on, and an explicit zero argument or a
negative argument always turns it off.

@c #### maybe this list should be extended and moved to its own node?

@cindex Auto Fill mode
@findex auto-fill-mode
  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.  @xref{Filling}.

@cindex Filladapt mode
@findex filladapt-mode
  Filladapt mode is an extension of Auto Fill mode which recognizes
@dfn{line prefixes} and automatically prepends them when automatically
breaking lines.  Filladapt mode is smart enough to recognize common
idioms for bullets (e.g., leading isolated hyphens) and enumerated
paragraphs, and insert appropriate leading whitespace (and omit the
bullet!)  It also does a good job of recognizing common quotation styles
in email.  Filladapt mode must be enabled in addition to Auto Fill
mode.  If Auto Fill mode is disabled, Filladapt mode will be
inactivated, but the indicator will remain in the modeline.

@cindex Overwrite mode
@findex overwrite-mode
  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 @samp{B} in @samp{FOOBAR}, and you type a @kbd{G} in Overwrite
mode, it changes to @samp{FOOGAR}, instead of @samp{FOOGBAR}.@refill

@cindex Pending Delete mode
@findex pending-delete-mode
Pending Delete mode cause buffer insertions and deletions to replace the
active region (with nothing, for deletions).  This is the common
behavior in most modern programs, but conflicts with the ``lightweight
selections'' used in the X Window System.

@cindex Abbrev mode
@findex abbrev-mode
  Abbrev mode allows you to define abbreviations that automatically expand
as you type them.  For example, @samp{amd} might expand to @samp{abbrev
mode}.  @xref{Abbrevs}, for full information.

@c Updated for 21.5.6 2002/03/13 sjt
@node Behaviors, Variables, Minor Modes, Customization
@section Behaviors
@cindex behavior

@dfn{Behaviors} are an alternative interface to minor modes.  The toggle
interface emphasizes the case-specific nature of a minor mode: use it
with @emph{this} major mode but not in @emph{those} buffers.  However,
this is inconvenient for behavior that depends on user preference.
For example, someone who discovers filladapt and really
likes it must toggle it separately in each buffer.  On the other hand,
after trying it for a while she might like to disable it everywhere,
having decided it doesn't work very well for her.

Use of mode hooks will invoke the minor mode automatically in the
future, but this is inconvenient (you must switch tasks to editing the
init file) and doesn't help with existing buffers in the session.  The
behavior interface addresses this problem.  The command
@code{enable-behavior} prompts (with completion) for a registered
behavior (denoted by a symbol), and enables it.  Conversely,
@code{disable-behavior} prompts for a behavior, and disables it.

@c #### This belongs in the Lispref in the description of creating
@c packages or in customize or both.

@c The package developer will register behaviors with XEmacs.  Then the
@c user invokes the @code{enable-behavior} and @code{disable-behavior}
@c functions to enable or disable a given behavior.  The behavior registry
@c was introduced in XEmacs 21.5.6.
@c
@c @defun enable-behavior behavior &optional force
@c Called interactively, prompt the user, read a behavior symbol name with
@c completion for @var{behavior}, and take @var{force} from the prefix
@c argument.  Then enable the behavior registered under the symbol
@c @var{behavior}.
@c
@c The optional argument @var{force} is unimplemented in 21.5.6.
@c @end defun
@c
@c @defun disable-behavior behavior &optional force
@c Called interactively, prompt the user, read a behavior symbol name with
@c completion for @var{behavior}, and take @var{force} from the prefix
@c argument.  Then disable the behavior registered under the symbol
@c @var{behavior}.
@c
@c The optional argument @var{force} is unimplemented in 21.5.6.
@c @end defun


@node Variables, Keyboard Macros, Behaviors, Customization
@section Variables
@cindex variable
@cindex option

  A @dfn{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-@code{nil},'' meaning that if the
variable's value is @code{nil}, the feature is off, but the feature is
on for @i{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 @code{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 @dfn{options}.  Most options are documented in this manual and
appear in the Variable Index (@pxref{Variable Index}).

  One example of a variable which is an option is @code{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 (@pxref{Filling}).

@menu
* Examining::           Examining or setting one variable's value.
* Easy Customization::  Convenient and easy customization of variables.
* Edit Options::        Examining or editing list of all variables' values.
* Locals::              Per-buffer values of variables.
* File Variables::      How files can specify variable values.
@end menu

@node Examining, Easy Customization, Variables, Variables
@subsection Examining and Setting Variables
@cindex setting variables

@table @kbd
@item C-h v
@itemx M-x describe-variable
Print the value and documentation of a variable.
@findex set-variable
@item M-x set-variable
Change the value of a variable.
@end table

@kindex C-h v
@findex describe-variable
  To examine the value of a single variable, use @kbd{C-h v}
(@code{describe-variable}), which reads a variable name using the
minibuffer, with completion.  It prints both the value and the
documentation of the variable.

@example
C-h v fill-column @key{RET}
@end example

@noindent
prints something like:

@smallexample
fill-column's value is 75

Documentation:
*Column beyond which automatic line-wrapping should happen.
Automatically becomes local when set in any fashion.
@end smallexample

@cindex option
@noindent
The star at the beginning of the documentation indicates that this variable
is an option.  @kbd{C-h v} is not restricted to options; it allows any
variable name.

@findex set-variable
  If you know which option you want to set, you can use @kbd{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,

@example
M-x set-variable @key{RET} fill-column @key{RET} 75 @key{RET}
@end example

@noindent
sets @code{fill-column} to 75, as if you had executed the Lisp expression
@code{(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.

@node Easy Customization, Edit Options, Examining, Variables
@subsection Easy Customization Interface

@findex customize
@cindex customization buffer
  A convenient way to find the user option variables that you want to
change, and then change them, is with @kbd{C-h C} (@code{customize}).
This command creates a @dfn{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.)

@menu
* Groups: Customization Groups.
                             How options are classified in a structure.
* Changing an Option::       How to edit a value and set an option.
* Face Customization::       How to edit the attributes of a face.
* Specific Customization::   Making a customization buffer for specific
                                options, faces, or groups.
@end menu

@node Customization Groups, Changing an Option, Easy Customization, Easy Customization
@subsubsection Customization Groups
@cindex customization groups

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

  @kbd{C-h C} (@code{customize}) creates a customization buffer that
shows the top-level @code{Emacs} group and the second-level groups
immediately under it.  It looks like this, in part:

@smallexample
/- 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.

@var{more second-level groups}

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

@end smallexample

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

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

  For example, the phrase @samp{[Open]} that appears in a second-level
group is an active field.  Invoking the @samp{[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 @code{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.

@findex customize-browse
  You can view the structure of customization groups on a larger scale
with @kbd{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
@samp{[+]}.  When the group contents are visible, this button changes to
@samp{[-]}; invoking that hides the group contents.

  Each group, option or face name in this buffer has an active field
which says @samp{[Group]}, @samp{[Option]} or @samp{[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.

@node Changing an Option, Face Customization, Customization Groups, Easy Customization
@subsubsection Changing an Option

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

@smallexample
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.
@end smallexample

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

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

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

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

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

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

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

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

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

   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.

@kindex M-TAB @r{(customization buffer)}
@findex widget-complete
  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 @kbd{M-@key{TAB}} (@code{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 @samp{[Value Menu]} appears before the value; invoke this
field to edit the value.  For a boolean ``on or off'' value, the active
field says @samp{[Toggle]}, and it changes to the other value.
@samp{[Value Menu]} and @samp{[Toggle]} edit the buffer; the changes
take effect when you use the @samp{Set for Current Session} operation.

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

@smallexample
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....
@end smallexample

@noindent
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 @samp{[DEL]} on that line.  To insert a new directory in
the list, invoke @samp{[INS]} at the point where you want to insert it.

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

@kindex TAB @r{(customization buffer)}
@kindex S-TAB @r{(customization buffer)}
@findex widget-forward
@findex widget-backward
  Two special commands, @key{TAB} and @kbd{S-@key{TAB}}, are useful for
moving through the customization buffer.  @key{TAB}
(@code{widget-forward}) moves forward to the next active or editable
field; @kbd{S-@key{TAB}} (@code{widget-backward}) moves backward to the
previous active or editable field.

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

@cindex saving option value
  Setting the option changes its value in the current Emacs session;
@dfn{saving} the value changes it for future sessions as well.  This
works by writing code into your init file so as to set the option
variable again each time you start Emacs.  @xref{Init File}.  To save
the option, invoke @samp{[State]} and select the @samp{Save for Future
Sessions} operation.

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

@table @samp
@item 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.

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

@item 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.
@end table

  The state of a group indicates whether anything in that group has been
edited, set or saved.  You can select @samp{Set for Current Session},
@samp{Save for Future Sessions} and the various kinds of @samp{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:

@smallexample
 [Set] [Save] [Reset]  [Done]
@end smallexample

@noindent
Invoking @samp{[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.

@node Face Customization, Specific Customization, Changing an Option, Easy Customization
@subsubsection Customizing Faces
@cindex customizing faces
@cindex bold font
@cindex italic font
@cindex fonts and 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:

@smallexample
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
@end smallexample

  Each face attribute has its own line.  The @samp{[@var{x}]} field
before the attribute name indicates whether the attribute is
@dfn{enabled}; @samp{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.

@xref{Faces}, for description of how @code{face-frob-from-locale-first}
variable affects changing @samp{Bold} and @samp{Italic} attributes.

@c Is this true for XEmacs?
@c  On a black-and-white display, the colors you can use for the
@c background are @samp{black}, @samp{white}, @samp{gray}, @samp{gray1},
@c and @samp{gray3}.  Emacs supports these shades of gray by using
@c background stipple patterns instead of a color.
@c
  Setting, saving and resetting a face work like the same operations for
options (@pxref{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 @samp{Show Display Types} in the menu you
get from invoking @samp{[State]}.

@c It would be cool to implement this
@c @findex modify-face
@c   Another more basic way to set the attributes of a specific face is
@c with @kbd{M-x modify-face}.  This command reads the name of a face, then
@c reads the attributes one by one.  For the color and stipple attributes,
@c the attribute's current value is the default---type just @key{RET} if
@c you don't want to change that attribute.  Type @samp{none} if you want
@c to clear out the attribute.

@node Specific Customization, , Face Customization, Easy Customization
@subsubsection 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.

@table @kbd
@item M-x customize-option @key{RET} @var{option} @key{RET}
Set up a customization buffer with just one option, @var{option}.
@item M-x customize-face @key{RET} @var{face} @key{RET}
Set up a customization buffer with just one face, @var{face}.
@item M-x customize-group @key{RET} @var{group} @key{RET}
Set up a customization buffer with just one group, @var{group}.
@item M-x customize-apropos @key{RET} @var{regexp} @key{RET}
Set up a customization buffer with all the options, faces and groups
that match @var{regexp}.
@item M-x customize-saved
Set up a customization buffer containing all options and faces that you
have saved with customization buffers.
@item M-x customize-customized
Set up a customization buffer containing all options and faces that you
have customized but not saved.
@end table

@findex customize-option
  If you want to alter a particular user option variable with the
customization buffer, and you know its name, you can use the command
@kbd{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.

@findex customize-face
  Likewise, you can modify a specific face, chosen by name, using
@kbd{M-x customize-face}.

@findex customize-group
  You can also set up the customization buffer with a specific group,
using @kbd{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 @samp{[Show]}.

@findex customize-apropos
  To control more precisely what to customize, you can use @kbd{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 @emph{all} groups, options and faces in the
customization buffer (but that takes a long time).

@findex customize-saved
@findex customize-customized
  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
@kbd{customize-saved} to look at the options and faces that you have
saved.  Use @kbd{M-x customize-customized} to look at the options and
faces that you have set but not saved.

@node Edit Options, Locals, Easy Customization, Variables
@subsection Editing Variable Values

@table @kbd
@item M-x list-options
Display a buffer listing names, values, and documentation of all options.
@item M-x edit-options
Change option values by editing a list of options.
@end table

@findex list-options
  @kbd{M-x list-options} displays a list of all Emacs option variables in
an Emacs buffer named @samp{*List Options*}.  Each option is shown with its
documentation and its current value.  Here is what a portion of it might
look like:

@smallexample
;; 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.
;;
@end smallexample

@findex edit-options
  @kbd{M-x edit-options} goes one step further and immediately selects the
@samp{*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:

@table @kbd
@item s
Set the variable point is in or near to a new value read using the
minibuffer.
@item x
Toggle the variable point is in or near: if the value was @code{nil},
it becomes @code{t}; otherwise it becomes @code{nil}.
@item 1
Set the variable point is in or near to @code{t}.
@item 0
Set the variable point is in or near to @code{nil}.
@item n
@itemx p
Move to the next or previous variable.
@end table

@node Locals, File Variables, Edit Options, Variables
@subsection Local Variables

@table @kbd
@item M-x make-local-variable
Make a variable have a local value in the current buffer.
@item M-x kill-local-variable
Make a variable use its global value in the current buffer.
@item 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.
@end table

@cindex local variables
   You can make any variable @dfn{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 @dfn{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.

@findex make-local-variable
  @kbd{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.

@findex make-variable-buffer-local
@cindex per-buffer variables
  @kbd{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 @code{make-local-variable} first.  We
call such variables @dfn{per-buffer} variables.

  Some important variables have been marked per-buffer already.  They
include @code{abbrev-mode}, @code{auto-fill-function},
@code{case-fold-search}, @code{comment-column}, @code{ctl-arrow},
@code{fill-column}, @code{fill-prefix}, @code{indent-tabs-mode},
@code{left-margin}, @*@code{mode-line-format}, @code{overwrite-mode},
@code{selective-display-ellipses}, @*@code{selective-display},
@code{tab-width}, and @code{truncate-lines}.  Some other variables are
always local in every buffer, but they are used for internal
purposes.@refill

Note: the variable @code{auto-fill-function} was formerly named
@code{auto-fill-hook}.

@findex kill-local-variable
  If you want a variable to cease to be local to the current buffer,
call @kbd{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.

@findex setq-default
  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 @code{setq-default}.  It works like @code{setq}.
If there is a local value in the current buffer, the local value is
not affected by @code{setq-default}; thus, the new global value may
not be visible until you switch to another buffer, as in the case of:

@example
(setq-default fill-column 75)
@end example

@noindent
@code{setq-default} is the only way to set the global value of a variable
that has been marked with @code{make-variable-buffer-local}.

@findex default-value
  Programs can look at a variable's default value with @code{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:

@example
(default-value 'fill-column)
@end example

@node File Variables, , Locals, Variables
@subsection Local Variables in Files
@cindex local variables in files

  A file can contain a @dfn{local variables list}, which specifies the
buffer-local 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 @samp{Local Variables:}, and ends
with a line containing the string @samp{End:}.  In between come the
variable names and values, one set per line, as @samp{@var{variable}:@:
@var{value}}.  The @var{value}s are not evaluated; they are used literally.

  The line which starts the local variables list does not have to say
just @samp{Local Variables:}.  If there is other text before @samp{Local
Variables:}, that text is called the @dfn{prefix}, and if there is other
text after, that is called the @dfn{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 @samp{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.@refill

  Two ``variable'' names are special in a local variables list: a value
for the variable @code{mode} sets the major mode, and a value for the
variable @code{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 @code{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:
@example
;;; Local Variables: ***
;;; mode:lisp ***
;;; comment-column:0 ***
;;; comment-start: ";;; "  ***
;;; comment-end:"***" ***
;;; End: ***
@end example

  Note that the prefix is @samp{;;; } and the suffix is @samp{ ***}.
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 @samp{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 minor modes like Auto Fill mode with a
local variable list.  That is inappropriate.  Those behaviors that seem
appropriate for almost any personal taste, such as setting up the syntax
table "symbol constituent" character class, are collected into a major
mode.  But 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
init file to turn it on (when appropriate) for you alone
(@pxref{Init File}).  Don't 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 @code{Local Variables}
section at the end of a file.

If the first line of a file contains two occurrences of @code{`-*-'},
XEmacs uses the information between them to determine what the major
mode and variable settings should be.  For example, these are all legal:

@example
        ;;; -*- mode: emacs-lisp -*-
        ;;; -*- mode: postscript; version-control: never -*-
        ;;; -*- tags-file-name: "/foo/bar/TAGS" -*-
@end example

For historical reasons, the syntax @code{`-*- modename -*-'} is allowed
as well; for example, you can use:

@example
        ;;; -*- emacs-lisp -*-
@end example

@vindex enable-local-variables
The variable @code{enable-local-variables} controls the use of local
variables lists in files you visit.  The value can be @code{t},
@code{nil}, or something else.  A value of @code{t} means local variables
lists are obeyed; @code{nil} means they are ignored; anything else means
query.

The command @code{M-x normal-mode} always obeys local variables lists
and ignores this variable.

@node Keyboard Macros, Key Bindings, Variables, Customization
@section Keyboard Macros

@cindex keyboard macros
  A @dfn{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
@kbd{C-n C-d} forty times, you can speed your work by defining a keyboard
macro to invoke @kbd{C-n C-d} and calling it with a repeat count of forty.

@c widecommands
@table @kbd
@item C-x (
Start defining a keyboard macro (@code{start-kbd-macro}).
@item C-x )
End the definition of a keyboard macro (@code{end-kbd-macro}).
@item C-x e
Execute the most recent keyboard macro (@code{call-last-kbd-macro}).
@item C-u C-x (
Re-execute last keyboard macro, then add more keys to its definition.
@item C-x q
When this point is reached during macro execution, ask for confirmation
(@code{kbd-macro-query}).
@item M-x name-last-kbd-macro
Give a command name (for the duration of the session) to the most
recently defined keyboard macro.
@item M-x insert-kbd-macro
Insert in the buffer a keyboard macro's definition, as Lisp code.
@end table

  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.

@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.
@end menu

@node Basic Kbd Macro, Save Kbd Macro, Keyboard Macros, Keyboard Macros
@subsection Basic Use

@kindex C-x (
@kindex C-x )
@kindex C-x e
@findex start-kbd-macro
@findex end-kbd-macro
@findex call-last-kbd-macro
  To start defining a keyboard macro, type @kbd{C-x (}
(@code{start-kbd-macro}).  From then on, anything you type continues to be
executed, but also becomes part of the definition of the macro.  @samp{Def}
appears in the mode line to remind you of what is going on.  When you are
finished, the @kbd{C-x )} command (@code{end-kbd-macro}) terminates the
definition, without becoming part of it.

  For example,

@example
C-x ( M-f foo C-x )
@end example

@noindent
defines a macro to move forward a word and then insert @samp{foo}.

You can give @kbd{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 @kbd{C-x )} an argument of 4, it executes the
macro immediately 3 additional times.  An argument of zero to @kbd{C-x
e} or @kbd{C-x )} means repeat the macro indefinitely (until it gets an
error or you type @kbd{C-g}).

  Once you have defined a macro, you can invoke it again with the
@kbd{C-x e} command (@code{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 @kbd{C-u C-x (}.  This is equivalent
to plain @kbd{C-x (} followed by retyping the whole definition so far.  As
a consequence it re-executes the macro as previously defined.

@node Save Kbd Macro, Kbd Macro Query, Basic Kbd Macro, Keyboard Macros
@subsection Naming and Saving Keyboard Macros

@findex name-last-kbd-macro
  To save a keyboard macro for longer than until you define the
next one, you must give it a name using @kbd{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 @kbd{M-x} or for
binding a key to with @code{global-set-key} (@pxref{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.

@findex insert-kbd-macro
  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:

@example
M-x insert-kbd-macro @key{RET} @var{macroname} @key{RET}
@end example

@noindent
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 @code{insert-kbd-macro} writes the Lisp code for you.
Then save the file.  You can load the file with @code{load-file}
(@pxref{Lisp Libraries}).  If the file you save in is your initialization file
(@pxref{Init File}), then the macro will be defined each
time you run Emacs.

  If you give @code{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.

@node Kbd Macro Query, , Save Kbd Macro, Keyboard Macros
@subsection Executing Macros With Variations

@kindex C-x q
@findex kbd-macro-query
  You can use @kbd{C-x q} (@code{kbd-macro-query}), to get an effect similar
to that of @code{query-replace}.  The macro asks you  each time
whether to make a change.  When you are defining the macro, type @kbd{C-x
q} at the point where you want the query to occur.  During macro
definition, the @kbd{C-x q} does nothing, but when you invoke the macro,
@kbd{C-x q} reads a character from the terminal to decide whether to
continue.

  The special answers to a @kbd{C-x q} query are @key{SPC}, @key{DEL},
@kbd{C-d}, @kbd{C-l}, and @kbd{C-r}.  Any other character terminates
execution of the keyboard macro and is then read as a command.
@key{SPC} means to continue.  @key{DEL} means to skip the remainder of
this repetition of the macro, starting again from the beginning in the
next repetition.  @kbd{C-d} means to skip the remainder of this
repetition and cancel further repetition.  @kbd{C-l} redraws the frame
and asks you again for a character to specify what to do.  @kbd{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 @kbd{C-M-c},
you are asked again how to continue with the keyboard macro.  If you
type a @key{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.@refill

  @kbd{C-u C-x q}, which is @kbd{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.  @xref{Recursive Edit}.

@node Key Bindings, Syntax, Keyboard Macros, Customization
@section Customizing Key Bindings

  This section deals with the @dfn{keymaps} that define the bindings
between keys and functions, and shows how you can customize these bindings.
@cindex command
@cindex function
@cindex command name

  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.

@menu
* Keymaps::    Definition of the keymap data structure.
               Names of Emacs's standard keymaps.
* Rebinding::  How to redefine one key's meaning conveniently.
* Disabling::  Disabling a command means confirmation is required
                before it can be executed.  This is done to protect
                beginners from surprises.
@end menu

@node Keymaps, Rebinding, Key Bindings, Key Bindings
@subsection Keymaps
@cindex keymap

@cindex global keymap
@vindex global-map
  The bindings between characters and command functions are recorded in
data structures called @dfn{keymaps}.  Emacs has many of these.  One, the
@dfn{global} keymap, defines the meanings of the single-character keys that
are defined regardless of major mode.  It is the value of the variable
@code{global-map}.

@cindex local keymap
@vindex c-mode-map
@vindex lisp-mode-map
  Each major mode has another keymap, its @dfn{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 @code{lisp-mode-map},
@code{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.

@cindex minibuffer
@vindex minibuffer-local-map
@vindex minibuffer-local-ns-map
@vindex minibuffer-local-completion-map
@vindex minibuffer-local-must-match-map
@vindex repeat-complex-command-map
@vindex isearch-mode-map
  There are local keymaps for the minibuffer, too; they contain various
completion and exit commands.

@itemize @bullet
@item
@code{minibuffer-local-map} is used for ordinary input (no completion).
@item
@code{minibuffer-local-ns-map} is similar, except that @key{SPC} exits
just like @key{RET}.  This is used mainly for Mocklisp compatibility.
@item
@code{minibuffer-local-completion-map} is for permissive completion.
@item
@code{minibuffer-local-must-match-map} is for strict completion and
for cautious completion.
@item
@code{repeat-complex-command-map} is for use in @kbd{C-x @key{ESC}}.
@item
@code{isearch-mode-map} contains the bindings of the special keys which
are bound in the pseudo-mode entered with @kbd{C-s} and @kbd{C-r}.
@end itemize

@vindex ctl-x-map
@vindex help-map
@vindex esc-map
  Finally, each prefix key has a keymap which defines the key sequences
that start with it.  For example, @code{ctl-x-map} is the keymap used for
characters following a @kbd{C-x}.

@itemize @bullet
@item
@code{ctl-x-map} is the variable name for the map used for characters that
follow @kbd{C-x}.
@item
@code{help-map} is used for characters that follow @kbd{C-h}.
@item
@code{esc-map} is for characters that follow @key{ESC}. All Meta
characters are actually defined by this map.
@item
@code{ctl-x-4-map} is for characters that follow @kbd{C-x 4}.
@item
@code{mode-specific-map} is for characters that follow @kbd{C-c}.
@end itemize

  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 @kbd{C-x} is the symbol @code{Ctl-X-Prefix}, whose function
definition is the keymap for @kbd{C-x} commands, the value of
@code{ctl-x-map}.@refill

  Prefix key definitions can appear in either the global
map or a local map.  The definitions of @kbd{C-c}, @kbd{C-x}, @kbd{C-h},
and @key{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.@refill

  A mode can also put a prefix definition of a global prefix character such
as @kbd{C-x} into its local map.  This is how major modes override the
definitions of certain keys that start with @kbd{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
@kbd{C-x} is looked up in both the major mode's own keymap for redefined
@kbd{C-x} commands and in @code{ctl-x-map}.  If the major mode's own keymap
for @kbd{C-x} commands contains @code{nil}, the definition from the global
keymap for @kbd{C-x} commands is used.@refill

@node Rebinding, Disabling, Keymaps, Key Bindings
@subsection Changing Key Bindings
@cindex key rebinding, this session
@cindex rebinding keys, this session

  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.

@menu
* Interactive Rebinding::      Changing Key Bindings Interactively
* Programmatic Rebinding::     Changing Key Bindings Programmatically
* Key Bindings Using Strings:: Using Strings for Changing Key Bindings
@end menu

@node Interactive Rebinding, Programmatic Rebinding, Rebinding, Rebinding
@subsubsection Changing Key Bindings Interactively
@findex global-set-key
@findex local-set-key
@findex local-unset-key

@table @kbd
@item M-x global-set-key @key{RET} @var{key} @var{cmd} @key{RET}
Defines @var{key} globally to run @var{cmd}.
@item M-x local-set-key @key{RET} @var{keys} @var{cmd} @key{RET}
Defines @var{key} locally (in the major mode now in effect) to run
@var{cmd}.
@item M-x local-unset-key @key{RET} @var{keys} @key{RET}
Removes the local binding of @var{key}.
@end table

@var{cmd} is a symbol naming an interactively-callable function.

When called interactively, @var{key} is the next complete key sequence
that you type.  When called as a function, @var{key} is a string, a
vector of events, or a vector of key-description lists as described in
the @code{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:

@example
M-x global-set-key @key{RET} C-f next-line @key{RET}
@end example

@noindent
redefines @kbd{C-f} to move down a line.  The fact that @var{cmd} is
read second makes it serve as a kind of confirmation for @var{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 @var{key}.  @var{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 @kbd{C-f} for @var{key}, Emacs enters
the minibuffer immediately to read @var{cmd}.  But if you type
@kbd{C-x}, another character is read; if that character is @kbd{4},
another character is read, and so on.  For example,@refill

@example
M-x global-set-key @key{RET} C-x 4 $ spell-other-window @key{RET}
@end example

@noindent
redefines @kbd{C-x 4 $} to run the (fictitious) command
@code{spell-other-window}.

@findex define-key
@findex substitute-key-definition
  The most general way to modify a keymap is the function
@code{define-key}, used in Lisp code (such as your init file).
@code{define-key} takes three arguments: the keymap, the key to modify
in it, and the new definition.  @xref{Init File}, for an example.
@code{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.

@node Programmatic Rebinding, Key Bindings Using Strings, Interactive Rebinding, Rebinding
@subsubsection Changing Key Bindings Programmatically

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

@findex define-key
@findex global-set-key

@table @kbd
@item  @code{(global-set-key @var{keys} @var{cmd})}
Defines @var{keys} globally to run @var{cmd}.
@item @code{(define-key @var{keymap} @var{keys} @var{def})}
Defines @var{keys} to run @var{def} in the keymap @var{keymap}.
@end table

@var{keymap} is a keymap object.

@var{keys} is the sequence of keystrokes to bind.

@var{def} is anything that can be a key's definition:

@itemize @bullet
@item
@code{nil}, meaning key is undefined in this keymap
@item
A command, that is, a Lisp function suitable for interactive calling
@item
A string or key sequence vector, which is treated as a keyboard macro
@item
A keymap to define a prefix key
@item
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
@item
A cons, @code{(string . defn)}, meaning that @var{defn} is the definition
(@var{defn} should be a valid definition in its own right)
@item
A cons, @code{(keymap . char)}, meaning use the definition of
@var{char} in map @var{keymap}
@end itemize

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.
@xref{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:

@itemize @bullet
@item
The keysym by itself is equivalent to a list of just that keysym, i.e.,
@code{f1} is equivalent to @code{(f1)}.
@item
A keystroke by itself is equivalent to a vector containing just that
keystroke, i.e.,  @code{(control a)} is equivalent to @code{[(control a)]}.
@item
You can use ASCII codes for keysyms that have them. i.e.,
@code{65} is equivalent to @code{A}. (This is not so much an
abbreviation as an alternate representation.)
@end itemize

Here are some examples of programmatically binding keys:

@example

;;;  Bind @code{my-command} to @key{f1}
(global-set-key 'f1 'my-command)

;;;  Bind @code{my-command} to @kbd{Shift-f1}
(global-set-key '(shift f1) 'my-command)

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

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

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

@end example

@comment ;; note that these next four lines are not synonymous:
@comment ;;
@comment (global-set-key '(meta control delete) 'my-command)
@comment (global-set-key '(meta control backspace) 'my-command)
@comment (global-set-key '(meta control h) 'my-command)
@comment (global-set-key '(meta control H) 'my-command)
@comment
@comment ;; note that this binds two key sequences: ``control-j'' and ``linefeed''.
@comment ;;
@comment (global-set-key "\^J" 'my-command)

@node Key Bindings Using Strings, , Programmatic Rebinding, Rebinding
@subsubsection 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:

@example
;;; Bind @code{end-of-line} to @kbd{C-f}
(global-set-key "\C-f" 'end-of-line)
@end example

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, @kbd{C-i} and @key{TAB} have
the same representation.  Therefore, when Emacs sees:

@example
(global-set-key "\C-i" 'end-of-line)
@end example

it is unclear whether the user intended to bind @kbd{C-i} or @key{TAB}.
The solution XEmacs adopts is to bind both of these key
sequences.

@cindex redefining keys
After binding a command to two key sequences with a form like:

@example
        (define-key global-map "\^X\^I" 'command-1)
@end example

it is possible to redefine only one of those sequences like so:

@example
        (define-key global-map [(control x) (control i)] 'command-2)
        (define-key global-map [(control x) tab] 'command-3)
@end example

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:

@example
        control h      backspace
        control l      clear
        control i      tab
        control m      return
        control j      linefeed
        control [      escape
        control @@      control space
@end example

@node Disabling, , Rebinding, Key Bindings
@subsection Disabling Commands
@cindex disabled command

  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-@code{nil}
@code{disabled} property on the Lisp symbol for the command.  These
properties are normally set by the user's init file with
Lisp expressions such as:

@example
(put 'delete-region 'disabled t)
@end example

@xref{Init File}.

  If the value of the @code{disabled} property is a string, that string
is included in the message printed when the command is used:

@example
(put 'delete-region 'disabled
     "Text deleted this way cannot be yanked back!\n")
@end example

@findex disable-command
@findex enable-command
  You can disable a command either by editing the init file
directly or with the command @kbd{M-x disable-command}, which edits the
init file for you.  @xref{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 init file.  You can use @kbd{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 @kbd{M-x}.
Disabling a command has no effect on calling it as a function from Lisp
programs.

@node Syntax, Init File, Key Bindings, Customization
@section The Syntax Table
@cindex syntax table

  All the Emacs commands which parse words or balance parentheses are
controlled by the @dfn{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.

@menu
* Entry: Syntax Entry.    What the syntax table records for each character.
* Change: Syntax Change.  How to change the information.
@end menu

@node Syntax Entry, Syntax Change, Syntax, Syntax
@subsection Information About Each Character

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

@itemize @bullet
@item
The syntactic class of the character, represented as a small integer
@item
The matching delimiter, for delimiter characters only
(the matching delimiter of @samp{(} is @samp{)}, and vice versa)
@item
A flag saying whether the character is the first character of a
two-character comment starting sequence
@item
A flag saying whether the character is the second character of a
two-character comment starting sequence
@item
A flag saying whether the character is the first character of a
two-character comment ending sequence
@item
A flag saying whether the character is the second character of a
two-character comment ending sequence
@end itemize

  The syntactic classes are stored internally as small integers, but are
usually described to or by the user with characters.  For example, @samp{(}
is used to specify the syntactic class of opening delimiters.  Here is a
table of syntactic classes, with the characters that specify them.

@table @samp
@item @w{-}
The class of whitespace characters.  Avoid use of the formerly
advertised @w{ }, because it is not supported by GNU Emacs.
@item w
The class of word-constituent characters.
@item _
The class of characters that are part of symbol names but not words.
This class is represented by @samp{_} because the character @samp{_}
has this class in both C and Lisp.
@item .
The class of punctuation characters that do not fit into any other
special class.
@item (
The class of opening delimiters.
@item )
The class of closing delimiters.
@item '
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.
@item "
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 @samp{\} and @samp{/} classes of escape
characters, which can be used to include a string-quote inside the
string.
@item $
The class of self-matching delimiters.  This is intended for @TeX{}'s
@samp{$}, which is used both to enter and leave math mode.  Thus,
a pair of matching @samp{$} characters surround each piece of math mode
@TeX{} input.  A pair of adjacent @samp{$} characters act like a single
one for purposes of matching.

@item /
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.
@item \
The class of C-style escape characters.  In practice, these are
treated just like @samp{/}-class characters, because the extra
possibilities for C escapes (such as being followed by digits) have no
effect on where the containing expression ends.
@item <
The class of comment-starting characters.  Only single-character
comment starters (such as @samp{;} in Lisp mode) are represented this
way.
@item >
The class of comment-ending characters.  Newline has this syntax in
Lisp mode.
@end table

@vindex parse-sexp-ignore-comments
  The characters flagged as part of two-character comment delimiters can
have other syntactic functions most of the time.  For example, @samp{/} and
@samp{*} 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
@code{parse-sexp-ignore-comments} is non-@code{nil}.  This variable is set
to @code{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.

@node Syntax Change, , Syntax Entry, Syntax
@subsection 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.

@findex modify-syntax-entry
  @kbd{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.

@enumerate
@item
The first character in the string specifies the syntactic class.  It
is one of the characters in the previous table (@pxref{Syntax Entry}).

@item
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.

@item
The remaining characters are flags.  The flag characters allowed are:

@table @samp
@item 1
Flag this character as the first of a two-character comment starting sequence.
@item 2
Flag this character as the second of a two-character comment starting sequence.
@item 3
Flag this character as the first of a two-character comment ending sequence.
@item 4
Flag this character as the second of a two-character comment ending sequence.
@end table
@end enumerate

@kindex C-h s
@findex describe-syntax
  Use @kbd{C-h s} (@code{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
@code{modify-syntax-entry} to set up that character's current syntax,
and some English to explain that string if necessary.

@node Init File, Audible Bell, Syntax, Customization
@section The Init File
@cindex init file
@cindex Emacs initialization file
@cindex key rebinding, permanent
@cindex rebinding keys, permanently

  When you start Emacs, it normally loads either @file{.xemacs/init.el}
or the file @file{.emacs} (whichever comes first) in your home directory.
This file, if it exists, should contain Lisp code.  It is called your
initialization file or @dfn{init file}.  Use the command line switch
@samp{-q} to tell Emacs whether to load an init file (@pxref{Entering
Emacs}).  Use the command line switch @samp{-user-init-file}
(@pxref{Command Switches}) to tell Emacs to load a different file
instead of @file{~/.xemacs/init.el}/@file{~/.emacs}.

When the init file is read, the variable @code{user-init-file} says
which init file was loaded.

  At some sites there is a @dfn{default init file}, which is the
library named @file{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 @code{inhibit-default-init} non-@code{nil}, then
@file{default} is not loaded.

  If you have a large amount of code in your init file, you should
byte-compile it to @file{~/.xemacs/init.elc} or @file{~/.emacs.elc}.

@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.
@end menu

@node Init Syntax, Init Examples, Init File, Init File
@subsection Init File Syntax

  The init file contains one or more Lisp function call
expressions.  Each consists of a function name followed by
arguments, all surrounded by parentheses.  For example, @code{(setq
fill-column 60)} represents a call to the function @code{setq} which is
used to set the variable @code{fill-column} (@pxref{Filling}) to 60.

  The second argument to @code{setq} is an expression for the new value
of the variable.  This can be a constant, a variable, or a function call
expression.  In the init file, constants are used most of the time.
They can be:

@table @asis
@item 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 @samp{#b}, @samp{#o}, and @samp{#x} are supported to
represent numbers in binary, octal, and hexadecimal notation (or radix).

@item 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: @samp{\n} for newline,
@samp{\b} for backspace, @samp{\r} for return, @samp{\t} for tab,
@samp{\f} for formfeed (control-l), @samp{\e} for escape, @samp{\\} for a
backslash, @samp{\"} for a double-quote, or @samp{\@var{ooo}} for the
character whose octal code is @var{ooo}.  Backslash and double-quote are
the only characters for which backslash sequences are mandatory.

You can use @samp{\C-} as a prefix for a control character, as in
@samp{\C-s} for ASCII Control-S, and @samp{\M-} as a prefix for
a Meta character, as in @samp{\M-a} for Meta-A or @samp{\M-\C-a} for
Control-Meta-A.@refill

@item Characters
Lisp character constant syntax consists of a @samp{?} followed by
either a character or an escape sequence starting with @samp{\}.
Examples: @code{?x}, @code{?\n}, @code{?\"}, @code{?\)}.  Note that
strings and characters are not interchangeable in Lisp; some contexts
require one and some contexts require the other.

@item True
@code{t} stands for `true'.

@item False
@code{nil} stands for `false'.

@item Other Lisp objects
Write a single-quote (') followed by the Lisp object you want.
@end table

@node Init Examples, Terminal Init, Init Syntax, Init File
@subsection Init File Examples

  Here are some examples of doing certain commonly desired things with
Lisp expressions:

@itemize @bullet
@item
Make @key{TAB} in C mode just insert a tab if point is in the middle of a
line.

@example
(setq c-tab-always-indent nil)
@end example

Here we have a variable whose value is normally @code{t} for `true'
and the alternative is @code{nil} for `false'.

@item
Make searches case sensitive by default (in all buffers that do not
override this).

@example
(setq-default case-fold-search nil)
@end example

This sets the default value, which is effective in all buffers that do
not have local values for the variable.  Setting @code{case-fold-search}
with @code{setq} affects only the current buffer's local value, which
is probably not what you want to do in an init file.

@item
Make Text mode the default mode for new buffers.

@example
(setq default-major-mode 'text-mode)
@end example

Note that @code{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, @code{text-mode} would be treated as a variable name.

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

@example
(setq text-mode-hook
  '(lambda () (auto-fill-mode 1)))
@end example

Here we have a variable whose value should be a Lisp function.  The
function we supply is a list starting with @code{lambda}, and a single
quote is written in front of it to make it (for the purpose of this
@code{setq}) a list constant rather than an expression.  Lisp functions
are not explained here; for mode hooks it is enough to know that
@code{(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.

@example
(setq text-mode-hook 'turn-on-auto-fill)
@end example

This is another way to accomplish the same result.
@code{turn-on-auto-fill} is a symbol whose function definition is
@code{(lambda () (auto-fill-mode 1))}.

@item
Load the installed Lisp library named @file{foo} (actually a file
@file{foo.elc} or @file{foo.el} in a standard Emacs directory).

@example
(load "foo")
@end example

When the argument to @code{load} is a relative pathname, not starting
with @samp{/} or @samp{~}, @code{load} searches the directories in
@code{load-path} (@pxref{Loading}).

@item
Load the compiled Lisp file @file{foo.elc} from your home directory.

@example
(load "~/foo.elc")
@end example

Here an absolute file name is used, so no searching is done.

@item
Rebind the key @kbd{C-x l} to run the function @code{make-symbolic-link}.

@example
(global-set-key "\C-xl" 'make-symbolic-link)
@end example

or

@example
(define-key global-map "\C-xl" 'make-symbolic-link)
@end example

Note once again the single-quote used to refer to the symbol
@code{make-symbolic-link} instead of its value as a variable.

@item
Do the same thing for C mode only.

@example
(define-key c-mode-map "\C-xl" 'make-symbolic-link)
@end example

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

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

@item
Bind the shifted version of @key{F1} to a command.

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

@item
Redefine all keys which now run @code{next-line} in Fundamental mode
to run @code{forward-line} instead.

@example
(substitute-key-definition 'next-line 'forward-line
                           global-map)
@end example

@item
Make @kbd{C-x C-v} undefined.

@example
(global-unset-key "\C-x\C-v")
@end example

One reason to undefine a key is so that you can make it a prefix.
Simply defining @kbd{C-x C-v @var{anything}} would make @kbd{C-x C-v}
a prefix, but @kbd{C-x C-v} must be freed of any non-prefix definition
first.

@item
Make @samp{$} have the syntax of punctuation in Text mode.
Note the use of a character constant for @samp{$}.

@example
(modify-syntax-entry ?\$ "." text-mode-syntax-table)
@end example

@item
Enable the use of the command @code{eval-expression} without confirmation.

@example
(put 'eval-expression 'disabled nil)
@end example
@end itemize

@node Terminal Init, , Init Examples, Init File
@subsection 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
@var{termtype}, the library is called @file{term/@var{termtype}} and it is
found by searching the directories @code{load-path} as usual and trying the
suffixes @samp{.elc} and @samp{.el}.  Normally it appears in the
subdirectory @file{term} of the directory where most Emacs libraries are
kept.@refill

  The usual purpose of the terminal-specific library is to define the
escape sequences used by the terminal's function keys using the library
@file{keypad.el}.  See the file
@file{term/vt100.el} for an example of how this is done.@refill

  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 @samp{aaa-48} and @samp{aaa-30-rv} both use
the library @file{term/aaa}.  The code in the library can use
@code{(getenv "TERM")} to find the full terminal type name.@refill

@vindex term-file-prefix
  The library's name is constructed by concatenating the value of the
variable @code{term-file-prefix} and the terminal type.  Your init
file can prevent the loading of the terminal-specific library by setting
@code{term-file-prefix} to @code{nil}.  @xref{Init File}.

@vindex term-setup-hook
  The value of the variable @code{term-setup-hook}, if not @code{nil}, is
called as a function of no arguments at the end of Emacs initialization,
after both your init file and any terminal-specific library have been
read.  @xref{Init File}.  You can set the value in the init file to
override part of any of the terminal-specific libraries and to define
initializations for terminals that do not have a library.@refill

@node Audible Bell, Faces, Init File, Customization
@section Changing the Bell Sound
@cindex audible bell, changing
@cindex bell, changing
@vindex sound-alist
@findex load-default-sounds
@findex play-sound

You can now change how the audible bell sounds using the variable
@code{sound-alist}.

@code{sound-alist}'s value is an list associating symbols with, among
other things, strings of audio-data.  When @code{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 @code{play-sound} with the argument @var{sound}. You
can also set the volume of the sound with the optional argument
@var{volume}.@refill
@cindex ding

Each element of @code{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:

@table @code
@item sound
A string of raw sound data, or the name of another sound to play.
The symbol @code{t} here means use the default X beep.

@item volume
An integer from 0-100, defaulting to @code{bell-volume}.

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

@item duration
If using the default X beep, the duration (milliseconds).
@end table

For compatibility, elements of `sound-alist' may also be of the form:

@example
( @var{sound-name} . @var{<sound>} )
( @var{sound-name} @var{<volume>} @var{<sound>} )
@end example

You should probably add things to this list by calling the function
@code{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.

@vindex bell-volume
The variable @code{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 @code{sound-alist} may override this value.
This variable applies to the standard X bell sound as well as sound files.

If the symbol @code{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.

@findex load-sound-file
You can add things to this list by calling the function
@code{load-sound-file}, which reads in an audio-file and adds its data to
the sound-alist. You can specify the sound with the @var{sound-name}
argument and the file into which the sounds are loaded with the
@var{filename} argument. The optional @var{volume} argument sets the
volume.

@code{load-sound-file (@var{filename sound-name} &optional @var{volume})}

To load and install some sound files as beep-types, use the function
@code{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.

@table @code
@item auto-save-error
An auto-save does not succeed

@item command-error
The Emacs command loop catches an error

@item undefined-key
You type a key that is undefined

@item undefined-click
You use an undefined mouse-click combination

@item no-completion
Completion was not possible

@item y-or-n-p
You type something other than the required @code{y} or @code{n}

@item yes-or-no-p
You type something other than @code{yes} or @code{no}
@end table

@node Faces, Frame Components, Audible Bell, Customization
@section Faces

XEmacs has objects called extents and faces.  An @dfn{extent}
is a region of text and a @dfn{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.

Basic Xft support has been merged into the mainline, and it looks pretty
good.  However, customization UI and documentation still leaves a lot to
be desired.  Here's a first cut, as a separate node.

@menu
* Xft Font Customization::  How to customize Xft fonts.
@end menu

@subsection Customizing Faces

You can change the face of an extent with the functions in
this section.  All the functions prompt for a @var{face} as an
argument; use completion for a list of possible values.

@table @kbd
@item M-x invert-face
Swap the foreground and background colors of the given @var{face}.
@item M-x make-face-bold
Make the font of the given @var{face} bold.  When called from a
program, returns @code{nil} if this is not possible.
@item M-x make-face-bold-italic
Make the font of the given @var{face} bold italic.
When called from a program, returns @code{nil} if not possible.
@item M-x make-face-italic
Make the font of the given @var{face} italic.
When called from a program, returns @code{nil} if not possible.
@item M-x make-face-unbold
Make the font of the given @var{face} non-bold.
When called from a program, returns @code{nil} if not possible.
@item M-x make-face-unitalic
Make the font of the given @var{face} non-italic.
When called from a program, returns @code{nil} if not possible.
@item M-x make-face-larger
Make the font of the given @var{face} a little larger.
When called from a program, returns @code{nil} if not possible.
@item M-x make-face-smaller
Make the font of the given @var{face} a little smaller.
When called from a program, returns @code{nil} if not possible.
@item M-x set-face-background
Change the background color of the given @var{face}.
@item M-x set-face-background-pixmap
Change the background pixmap of the given @var{face}.
@item M-x set-face-background-pixmap-file
A simpler version but with filename completion.
@item M-x set-face-background-placement
Change the placement of the background pixmap of the given @var{face}.
@item M-x set-face-font
Change the font of the given @var{face}.
@item M-x set-face-foreground
Change the foreground color of the given @var{face}.
@item M-x set-face-underline-p
Change whether the given @var{face} is underlined.
@end table

@findex make-face-larger
@findex make-face-smaller

@findex invert-face
You can exchange the foreground and background color of the selected
@var{face} with the function @code{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
@var{frame} to specify which frame is affected; otherwise, all frames
are affected.

@findex make-face-bold
@findex make-face-bold-italic
@findex make-face-italic
@findex make-face-unbold
@findex make-face-unitalic
@vindex face-frob-from-locale-first
The work of @code{make-face-bold}, @code{make-face-bold-italic},
@code{make-face-italic}, @code{make-face-unbold},
@code{make-face-unitalic} functions is affected by
@code{face-frob-from-locale-first} variable.  If it is @code{nil}, those
functions first try to manipulate device specific data like X font names
to obtain the desired font face specification.  This may be unsuitable
in environments using different font face specifications for different
frames, non-Mule environments in particular.

If the variable is non-@code{nil}, those functions first try to figure
out whether the face font is the same as one of predefined faces:
@code{default}, @code{bold}, @code{italic}, @code{bold-italic}.  If it
is the same, then the new face font specification is set to be the same
as that of a corresponding predefined face.  Thus if the predefined face
is set up properly for different frames, the same will hold for the face
being changed by the functions.  This is the behavior one might desire
in non-Mule environments mentioned above: face being changed still looks
right in all frames.

How predefined faces might be set up for different frames in such an
environments is described in @ref{Face Resources}.

@findex set-face-background
You can set the background color of the specified @var{face} with the
function @code{set-face-background}.  The argument @code{color} should
be a string, the name of a color.  When called from a program, if the
optional @var{frame} argument is provided, the face is changed only
in that frame; otherwise, it is changed in all frames.

@findex set-face-background-pixmap
You can set the background pixmap of the specified @var{face} with the
function @code{set-face-background-pixmap}.  The pixmap argument
@var{name} should be a string, the name of a file of pixmap data.  The
directories listed in the @code{x-bitmap-file-path} variable are
searched.  The bitmap may also be a list of the form @code{(@var{width
height data})}, where @var{width} and @var{height} are the size in
pixels, and @var{data} is a string containing the raw bits of the
bitmap.  If the optional @var{frame} argument is provided, the face is
changed only in that frame; otherwise, it is changed in all frames.

The variable @code{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
@code{nil}, the list is initialized from the @code{*bitmapFilePath}
resource.

If the environment variable @b{XBMLANGPATH} is set, then it is consulted
before the @code{x-bitmap-file-path} variable.

@findex set-face-background-pixmap
Alternately, you can use a simpler version of
@code{set-face-background-pixmap} called
@code{set-face-background-pixmap-file}. This function does not give you
as much control on the pixmap instantiator, but provides filename
completion.

@findex set-face-background-placement
You can set the placement of the background pixmap of the specified
@var{face} with the function @code{set-face-background-placement}. The
placement argument can be either @code{absolute} or @code{relative} (the
default). A @code{relative} placement means that the pixmap is attached
to the frame and moves with it. An @code{absolute} placement means that
the pixmap is rather attached to the frame's root window, so that when
you move the frame on the screen, it will appear to ``slide'' on the
pixmap. This placement mode can be used to achieve pseudo-translucency
for a frame, for example by setting the default face's background pixmap
to the root window's one.

@findex set-face-font
You can set the font of the specified @var{face} with the function
@code{set-face-font}.  The @var{font} argument should be a string, the
name of a font.  When called from a program, if the
optional @var{frame} argument is provided, the face is changed only
in that frame; otherwise, it is changed in all frames.

The syntax of the @var{font} argument varies according to platform.  In
each of the following syntaxes, the example shows how to specify a
14-point upright bold Courier font.

@table @strong
@item X11
The X11 syntax is defined by the @dfn{X Logical Font Descriptor} (XLFD)
standard.  An XLFD contains 14 fields each preceded by a hyphen:
foundry, family, weight, slant, swidth, adstyle, pixelsize, pointsize,
xresolution, yresolution, spacing, averagewidth, registry, and encoding.
It is usually sufficient to specify family, weight, slant, pointsize,
registry, and encoding, wildcarding the rest with @samp{*}.  If you're
not sure what's available, you can wildcard some of the fields usually
specified, too.  Here's our example font in XLFD syntax:
@code{"-*-courier-bold-r-*-*-*-140-*-*-*-*-iso8859-*"}.
The XLFD syntax is also used for GTK+ version 1.  XLFD names must be
encoded in ISO-8859-1.

@item Xft
The Xft syntax is defined by the @file{fontconfig} library
@ref{Font Names,,,fontconfig}.  It is less a font naming convention than
a way to express any arbitrary subset of the font's properties in a
syntax that is both human- and machine-readable.  A @file{fontconfig}
font name contains the family, a hyphen, and the pointsize, followed by
an arbitrary sequence of properties.  Each property consists of a colon,
a keyword, an equals sign, and the property value.  Here's our example
font in @file{fontconfig} syntax: @code{"Courier-14:weight=bold"}.  This
syntax admits ``style abbreviations'' which can be user-defined.  A
style is a single keyword denoting a sequence of properties.  So the
example font may be abbreviated to @code{"Courier-14:bold"} ("bold" is a
standard abbreviation for "weight=bold").  The @file{fontconfig} syntax
is also used for GTK+ version 2.  @file{fontconfig} names must be
encoded in UTF-8.

@item MS-Windows
The MS Windows syntax is superficially similar to that of Xft but
actually is more like XLFD.  A font name consists of five fields,
family, size, slant, weight, and encoding, each expressed as a keyword
taking on standardized values (except family, which is just a name).
Here's our example font in MS Windows syntax:
@code{"Courier:14:Bold:Western"}.
@end table

@findex set-face-foreground
You can set the foreground color of the specified @var{face} with the
function @code{set-face-foreground}.  The argument @var{color} should be
a string, the name of a color.  If the optional @var{frame} argument is
provided, the face is changed only in that frame; otherwise, it is
changed in all frames.

@findex set-face-underline-p
You can set underline the specified @var{face} with the function
@code{set-face-underline-p}. The argument @var{underline-p} can be used
to make underlining an attribute of the face or not. If the optional
@var{frame} argument is provided, the face is changed only in that
frame; otherwise, it is changed in all frames.

@node Xft Font Customization, , Faces, Faces
@subsection Xft Font Customization

This section was written by @email{stephen@@xemacs.org,Stephen Turnbull},
and is very much a work in progress.  I've tried to provide pointers to
as much of the relevant information as possible, but many of the APIs
and UIs are in flux, so it seemed more work than it was worth to
completely translate the tables of constants, and so on.  Feel free to
ask for clarifications, @emph{etc.}  Please Cc
@email{xemacs-beta@@xemacs.org,the XEmacs Beta Testers' mailing list},
as that is the issue tracking channel of record, and there are a few
others who can answer the questions or improve documentation when I'm
not able to respond quickly.

@c Don't blame Ben (or Eric and Matthias, for that matter).  Feel free to
@c add, edit, and share the blame, everybody!

As of mid-2005, we have added support for the
@uref{http://www.freedesktop.org/wiki/Software/Xft/,Xft} library,
which provides a more robust @emph{font configuration} mechanism via
Keith Packard's
@uref{http://www.freedesktop.org/wiki/Software/fontconfig/,fontconfig}
library; improved glyph rendering, including antialiasing, via the
@uref{http://freetype.org/,freetype} library; and client-side
rendering (saving bandwidth and server memory) via the
@file{XRender extension}.

@c #### Describe Alexey Gladkov and Yury Konovalov's work.

@menu
* Font configuration::    Faces versus fontconfig.
* fontconfig::            How fontconfig finds fonts.
* fontconfig font names:: How fonts are named when using fontconfig.
* Font menus::            Why the XEmacs font menus are broken.
* X resources::           Specification of fonts with X resources.
* Specifiers charsets and languages:: On the absence of language specifiers.
* Known Problems::        XEmacs features that don't work with Xft.
* Variables Used with Xft and Fontconfig:: Lisp Xft/fontconfig variables.
@end menu

@node Font configuration, fontconfig, Xft Font Customization, Xft Font Customization
@subsubsection Font configuration

In XEmacs, font configuration is handled via @emph{faces}.  Currently
XEmacs uses a special type of @emph{font specifier} to map XEmacs
locales to font names.  Especially under X11, this can cause annoying
problems because of the unreliability of X servers' mappings from
@samp{XLFD} names to X11 fonts, over which XEmacs has no influence
whatsoever.  However, the @file{fontconfig} library which is used with
@file{Xft} provides much more reliable mapping, along with a more
reliably parsable naming scheme similar to that used by TrueType fonts
on MS Windows and the Macintosh.

@node fontconfig, fontconfig font names, Font configuration, Xft Font Customization
@subsubsection fontconfig

Fontconfig is dramatically different from the X model in several ways.
In particular, when queried for a font @emph{fontconfig always returns a
font}, whereas X queries may return ``not found.''  However, the font
returned need not be anything like the desired font.  This is not really
a problem in practice, because users generally have a pretty good idea
of what fonts are available on their display.  However, users should be
aware that as of XEmacs 21.5.26 the font selection internals have not
been revised to account for this radically different model, so some
surprising results are possible.

From the user's point of view, @file{fontconfig} provides a naming
convention which is @emph{precise}, @emph{accurate}, and
@emph{convenient}.  Precision means that all properties available in the
programming API can be individually specified.  Accuracy means that the
truename of the font is exactly the list of all properties specified by
the font.  Thus, the anomalies that occur with XLFDs on many servers
(including modern Linux distributions with XFree86 or X.org servers)
cannot occur.  Convenience is subjective, of course.  However,
@file{fontconfig} provides a configuration system which (1) explicitly
specifies the defaults and substitutions that will be made in processing
user queries, (2) allows the user to specify search configuration,
abbreviations, substitutions, and defaults that override the system's,
in the same format as used by system files, and (3) allows flexible
aliases that can resolve to any of several actual fonts depending on
which fonts are installed.

Further, a @dfn{standard minimal configuration} is defined that ensures
that at least the @emph{serif}, @emph{sans-serif}, and @emph{monospace}
font aliases are available on all @file{fontconfig} systems.

@node fontconfig font names, Font menus, fontconfig, Xft Font Customization
@subsubsection fontconfig font names

@file{fontconfig} font names are very regular, and constitute a precise
and extensible specification of a font's properties.

The basic @file{fontconfig} font name has three components: the font
family name, the size, and a list of named attribute fields.  All
attribute names and values are strings encoded in Unicode UTF-8, or
decimal numbers with optional decimal point and fraction.  The
characters @samp{-}, @samp{:}, @samp{,}, @samp{=}, and @samp{\} are
syntactically significant to @file{fontconfig}.  They may be used in
font name components by the familiar mechanism of backslash escaping.
This simply removes any special meaning from the following character.
It is always safe to use an escape even if it is not needed.

Most string values are case-insensitive, but this is attribute-specific.

The @dfn{font family name} is an arbitrary string, which may contain any
character, including spaces, hyphens, and commas.  Don't forget to
escape hyphens, colons, commas, and backslashes!

The @dfn{size} is a decimal number with optional decimal point and
fractional part.  It is interpreted as point size.

A @dfn{named attribute field} is a key-value pair separated by an equal
sign.  Some attributes have predefined semantics.  (These include such
familiar attributes as @samp{slant} and @samp{dpi} -- note that
@file{fontconfig} does not distinguish between vertical and horizontal
resolution!

The basic syntax of a font name is simple and regular.  The @emph{font
family name} comes first, followed by a hyphen and the @emph{size},
followed by a list of @emph{named attribute fields}, each introduced by
a colon:

@example
@var{font family name}-@var{size}:@var{key1}=@var{value1}:@var{key2}=@var{value2}...
@end example

There are four extensions to the basic syntax.  First, all of the
fields are optional.  If size is omitted, the hyphen should be omitted
as well.  There should never be a trailing colon.  Note that
@file{fontconfig} does @emph{not} interpret an omitted field as
``default to current.''  @file{fontconfig} does not have access to that
context.  Instead, omitted fields are filled in according to a set of
defaults specified in the system @file{fonts.conf} file and in the
user's @file{.fonts.cont} file.  The user's configuration gets
precedence, of course.

The second is that the @emph{font family name}, the @emph{size}, and the
@emph{value} component of a @emph{named attribute field} may be a
comma-separated list of values.  This is called a @dfn{pattern}.  In
queries, @file{fontconfig} tries to match each entry in the list in
order.  (I suspect that order of attributes is also significant.
@emph{I.e.}, font family always gets highest precedence, followed by
size, followed by the remaining named attributes.  Testing and reports
to the @email{xemacs-beta@@xemacs.org,XEmacs Beta Testers mailing list}
are very welcome!)

The third is the definition of @dfn{constants} to represent numerical
values.  For example, both @samp{slant} and @samp{weight} are defined as
integer attributes, but the magnitudes are arbitrary; only the ordering
and relative distances are useful.  (``Relative distance'' is used to
implement the concept that although strictly speaking @emph{italic} and
@emph{oblique} are different faces, most users don't know the
difference, and even professional typographers would agree that they are
much closer to each other than either is to @emph{roman}.)  So
@emph{constants} like @samp{roman} (0) and @samp{italic} (100) are
defined for @samp{slant}, and @samp{medium} (100) and @samp{bold} (200)
are defined for @samp{weight}.

The fourth is that a @dfn{style} may be defined as an alias for an
instance of a @emph{named attribute field}, that is, specifying both key
and value.  The @emph{styles} @samp{bold}, an alias for
@samp{weight=200}, and @samp{italic}, an alias for @samp{slant=100}, are
commonly used.

Styles and constants can be defined by the application.  XEmacs
currently defines none, but suggestions are welcome if some convenient
alias is lacking from @file{fontconfig}.  Note that we will not provide
additional aliases where standard ones exist, @emph{e.g.}, @samp{heavy}
as an additional alias for @samp{bold} would almost certainly be
rejected.  These cause more confusion than they are worth, and would
decrease portability of user specifications to other applications.

(Attributes can also be defined, but they must be implemented by the
fonts to be useful.  Until XEmacs provides its own fonts with
non-standardized attributes, this is not useful.)

Here are some examples of font names and query patterns:

@example
Times-12                    12-point Times Roman
Times-12:bold               12-point Times Bold
Courier:italic              Courier Italic in the default size
Monospace:matrix=1 .1 0 1   The user's preferred monospace font
                            with artificial obliquing
Mikachan\-PB-16             16-point Mikachan-PB
LucidaTypewriter,Courier-9  9-point LucidaTypewriter if available,
                            otherwise 9-point Courier
@end example

Note how @emph{styles} are used in the second and third examples, how
@samp{matrix} has a complex value containing spaces, and the
escaped hyphen in the font family name @samp{Mikachan\-PB}.

@c #### FIXME here and also in fontconfig.texi (in general-docs package).
Here is a (somewhat outdated) list of current standard named attributes:

@example
Property        CPP symbol      Type    Description

family          FC_FAMILY       String  Font family name
style           FC_STYLE        String  Font style. Overrides weight and slant
slant           FC_SLANT        Int     Italic, oblique or roman
weight          FC_WEIGHT       Int     Light, medium, demibold, bold or black
size            FC_SIZE         Double  Point size
aspect          FC_ASPECT       Double  Stretch glyphs horizontally, then hint
pixelsize       FC_PIXEL_SIZE   Double  Pixel size
spacing         FC_SPACING      Int     Proportional, monospace or charcell
foundry         FC_FOUNDRY      String  Font foundry name
antialias       FC_ANTIALIAS    Bool    Should glyphs be antialiased?
hinting         FC_HINTING      Bool    Should the rasterizer use hinting?
verticallayout  FC_VERTICAL_LAYOUT Bool Use vertical layout
autohint        FC_AUTOHINT     Bool    Use autohinter instead of normal hinter
globaladvance   FC_GLOBAL_ADVANCE Bool  Use font global advance data
file            FC_FILE         String  The filename holding the font
index           FC_INDEX        Int     The index of the font within the file
ftface          FC_FT_FACE      FT_Face Use the specified FreeType face object
rasterizer      FC_RASTERIZER   String  Which rasterizer is in use
outline         FC_OUTLINE      Bool    Whether the glyphs are outlines
scalable        FC_SCALABLE     Bool    Whether glyphs can be scaled
scale           FC_SCALE        Double  Point->pixel conversion scale factor
dpi             FC_DPI          Double  Target dots per inch
rgba            FC_RGBA         Int     unknown, rgb, bgr, vrgb, vbgr, none
                                        - subpixel geometry
source		FC_SOURCE	String  X11, freetype
minspace        FC_MINSPACE     Bool    Eliminate leading from line spacing
charset         FC_CHARSET      CharSet Unicode chars encoded by the font
lang            FC_LANG         String  List of RFC-3066-style languages
                                        this font supports
fontversion	FC_FONTVERSION  Int     From 'head' table
@end example

Here is a list of current standard constants:

@example
Constant        Property        CPP symbol

light           weight          FC_WEIGHT_LIGHT
medium          weight          FC_WEIGHT_MEDIUM
demibold        weight          FC_WEIGHT_DEMIBOLD
bold            weight          FC_WEIGHT_BOLD
black           weight          FC_WEIGHT_BLACK
roman           slant           FC_SLANT_ROMAN
italic          slant           FC_SLANT_ITALIC
oblique         slant           FC_SLANT_OBLIQUE
proportional    spacing         FC_PROPORTIONAL
mono            spacing         FC_MONO
charcell        spacing         FC_CHARCELL
unknown         rgba            FC_RGBA_UNKNOWN
rgb             rgba            FC_RGBA_RGB
bgr             rgba            FC_RGBA_BGR
vrgb            rgba            FC_RGBA_VRGB
vbgr            rgba            FC_RGBA_VBGR
none            rgba            FC_RGBA_NONE
@end example

Note that this is the @file{fontconfig} API list; you can expect that
XEmacs will define corresponding keywords by substituting @samp{:} for
the leading @samp{FC_}, @samp{-} for @samp{_}, removing the key of the
attribute if present, and lowercasing the name.  Thus
@samp{FC_WEIGHT_BOLD} becomes @samp{:bold}.
@kbd{M-x apropos RET fc-.*-mapping} will give a list of variables each
of which lists such keywords and their meanings.

@node Font menus, X resources, fontconfig font names, Xft Font Customization
@subsubsection Font menus

The @samp{Options->Font} and @samp{Options->Font Sizes} menus are
broken, by design, not just by @file{Xft}.  The problem is that many
fonts are unavailable because they don't match the current size---which
is very strange, since @file{Xft} fonts are of course scalable.  But the
whole idea of requiring that the font match the size is strange.  And
the @samp{Options->Font Weights} menu is just disabled, and has been for
eons.

@node X resources, Specifiers charsets and languages, Font menus, Xft Font Customization
@subsubsection X resources

Currently there are @emph{four} treatments of font resources.  There are
the @samp{XEmacs.@var{face}.attributeFont} resources used to set a
single global font specification.  In the widgets, some (still) have a
@samp{font} resource using the automatic @file{Xt} resource conversion
to X's @samp{FontStruct}, some have separate @samp{font} and @samp{xftFont}
resources with the former automatically converted to @samp{FontStruct}
by @file{Xt} and the latter left as a string, to be converted to a
fontconfig @samp{FcPattern} by
@samp{FcParseName} later, and some have a single @samp{font} resource
which is converted to @samp{FontStruct} by @file{Xt} or the latter left
as a string, depending on whether @file{Xft} was enabled by
@samp{configure} or not.

Eventually these should be converted to use the face
approach, perhaps with some way to set specifications for individual
widgets, frames, or buffers.  This will require some careful design work
to incorporate face support in the widgets.  Stephen's current thinking
is that XEmacs should just accept any
or all of @samp{font}, @samp{fontSet}, and @samp{fontList} resources,
treat them all as lists of font names, either @samp{XLFD}- or
@file{fontconfig}-style, parse them ourselves (ie, not use the @file{Xt}
resource manager), and add them to font specifiers as appropriate.  But
this will require a bit of thought to obey POLA vis-a-vis usual @file{Xt}
conventions.

@node Specifiers charsets and languages, Known Problems, X resources, Xft Font Customization
@subsubsection Specifiers, charsets, and languages

Traditionally Mule uses a rather rigid and low-level abstraction, the
@emph{charset}, to characterize font repertoires.  Unfortunately,
support for a given charset is generally neither necessary nor
sufficient to support a language.  Worse, in XEmacs's current
implementation Xft doesn't help much.  Instead you need to add the fonts
for different charsets to the font specifier in the right order.

There currently is no explicit way to specify that a particular font be
used only for a given language.  However, since many fonts support only
a limited repertoire such as ISO 8859/1, you can use the precedence of
specifications for a given specifier locale to get something of this
effect for non-Latin character sets.  This will normally work rather
poorly for multiple Latin character sets, however, because the
repertoires tend to have large amounts of overlap.  Support for
specifying font by @emph{language} as well as by character set is
planned.

Because fonts supporting other languages tend to support English as
well, if you want to use one font for English and another for the other
language, you must use the @code{append} method when adding font
specifications for the @emph{other} language.

However, this simple method leaves you with a problem if you want to
change the other language's font: you have to remove the existing
specification so it won't shadow the new one when you append.

In order to provide a convenient way to change ``other-language fonts'',
I use @code{remove-tag-set-append} and @code{define-specifier-tag} like
this:

@example
(define-specifier-tag 'lang-ja)
;; No, I don't try to do real work with this font!  But it makes it
;; obvious that I got the requested font.  :-)
(set-face-font 'default "AirCut-14")
(set-face-font 'default "Kochi Mincho-14" nil '(lang-ja) 'append)
;; Oops, too sober.  Try something to match AirCut.
(set-face-font 'default "Mikachan-14"
               nil '(lang-ja) 'remove-tag-set-append)
@end example

The only way to configure widget fonts at the present time is to use X
resources (or hack the source and rebuild).  Currently supported widgets
are
@itemize
@item
menubars
@item
tab controls
@end itemize

Here are the resources I use.  @strong{Warning:} @emph{This interface
will change.  Pay attention to beta announcements, and complain loudly
if changes aren't documented here!}  The tab control and menubar have
separate @code{Font} and @code{FcFontName} resources, and use the X
resource manager to instantiate a FontStruct from the @code{Font}
resource.  There is no converter facility for @code{FcFontName} yet, and
creating one that handles both FontStruct and XftFont depending on
XEmacs's configuration and the font name seems error-prone at best.
Probably we will use a simple string representation for this resource,
and convert to a face in XEmacs rather than a font in Xt/Xft.  (The
older @code{XftFont} resource is deprecated.  There is code intended to
implement backward compatibility, but there are repots that it doesn't
work properly.)
@example
XEmacs*Tabs.fcFontName: Bitstream Vera Sans-16
XEmacs*menubar*fcFontName: Bitstream Vera Sans-16
XEmacs.modeline.attributeFont: Bitstream Charter-16
XEmacs.default.attributeFont: Bitstream Vera Sans Mono-16
@end example
I highly recommend use of a proportional font in the modeline because it
allows a lot more text to fit there.
@c Previously the font sizes were quite varied, and there was a comment
@c that this weirdness gave good balance.  This isn't true on my main
@c platform, Mac OS X, and needs to be rechecked on Linux, where it was
@c observed.

@node Known Problems, Variables Used with Xft and Fontconfig, Specifiers charsets and languages, Xft Font Customization
@subsubsection Known Problems

@table @code
@item Options->Font
@itemx Options->Font Size
These menus don't work.  All fonts are greyed out.  All sizes are
available, but many (most?) faces don't change size, in particular,
@samp{default} does not.

@item Antialiased text bleeding outside of reported extent
This is most obvious with the underscore character in that
font, and with cursors.  The bottom of the underscore is antialiased,
and insertions or deletions in the same line before the underscore leave
a series of "phantom" underlines.

I think this is probably an Xft bug, but I'm not sure.
@end table

@node Variables Used with Xft and Fontconfig, , Known Problems, Xft Font Customization
@subsubsection Variables Used with Xft and Fontconfig

@defvar xft-debug-level

Level of debugging messages to issue to stderr for @var{Xft}.
A nonnegative integer.  Set to 0 to suppress all warnings.
Default is 1 to ensure a minimum of debugging output at initialization.
Higher levels give more information.
@end defvar

@defvar xft-version

The major version number of the Xft library compiled with.
@end defvar

@defvar xft-xlfd-font-regexp

Regular expression matching XLFD font names.
@end defvar


@node Frame Components, X Resources, Faces, Customization
@section Frame Components

You can control the presence and position of most frame components, such
as the menubar, toolbars, and gutters.

This section is not written yet.  Try the Lisp Reference Manual:
@ref{Menubar,,,lispref,}, @ref{Toolbar Intro,,,lispref,}, and
@ref{Gutter Intro,,,lispref,}.

@node X Resources, , Frame Components, Customization
@section X Resources
@cindex X resources
@findex x-create-frame

Historically, XEmacs used the X resource application class @samp{Emacs}
for its resources.  Unfortunately, GNU Emacs's usage of resources has
evolved differently from XEmacs's, and especially in the case of fonts
semantics are not compatible between the two Emacsen.  Thus, sharing of
the application class can easily lead to trouble.

XEmacs now uses the X resource application class @samp{XEmacs}.
Versions since 21.5.21 do this unconditionally.  To attempt to maintain
some backward compatibility, previous versions checked the X resource
database for resources starting in @samp{XEmacs}, and if none were
found, @samp{Emacs} was used.  This behavior is likely to be obsoleted,
so you should move your X resources to using the @samp{XEmacs} class.
In the short term, to stay with the old behavior, start XEmacs with the
environment variable @b{USE_EMACS_AS_DEFAULT_APPLICATION_CLASS} set to
some non-empty value; this will restore the pre-21.5.21 behavior.
@c #### is this documented in the Lispref?
Lisp programs can examine the variable @code{x-emacs-application-class}
to determine which is being used in the running application.

The examples in this section assume the application class is
@samp{XEmacs}.

Most of XEmacs's resources are set per-frame.  Each XEmacs frame can
have its own name or the same name as another, depending on the name
passed to the @code{make-frame} function.  Up until 21.5.21, the default
frame name was @samp{emacs}; since then, it has been @samp{XEmacs}, but
in the short term the old default can be restored by the
@b{USE_EMACS_AS_DEFAULT_APPLICATION_CLASS} environment variable
mentioned above.
@c #### Cheesy.  Variable should be documented here.
See the docstring for the Lisp variable `default-frame-name'.

You can specify resources for all frames with the syntax:

@example
XEmacs*parameter: value
@end example
@noindent

or

@example
XEmacs*EmacsFrame.parameter:value
@end example
@noindent

You can specify resources for a particular frame with the syntax:

@example
XEmacs*FRAME-NAME.parameter: value
@end example
@noindent

@menu
* Geometry Resources::     Controlling the size and position of frames.
* Iconic Resources::       Controlling whether frames come up iconic.
* Resource List::          List of resources settable on a frame or device.
* Face Resources::         Controlling faces using resources.
* Widgets::                The widget hierarchy for XEmacs.
* Menubar Resources::      Specifying resources for the menubar.
@end menu

@node Geometry Resources, Iconic Resources, X Resources, X Resources
@subsection Geometry Resources

To make the default size of all XEmacs frames be 80 columns by 55 lines,
do this:

@example
XEmacs*EmacsFrame.geometry: 80x55
@end example
@noindent

To set the geometry of a particular frame named @samp{fred}, do this:

@example
XEmacs*fred.geometry: 80x55
@end example
@noindent

Important! Do not use the following syntax:

@example
XEmacs*geometry: 80x55
@end example
@noindent

You should never use @code{*geometry} with any X application. It does
not say "make the geometry of XEmacs be 80 columns by 55 lines."  It
really says, "make XEmacs and all subwindows thereof be 80x55 in whatever
units they care to measure in."  In particular, that is both telling the
XEmacs 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 XEmacs frames to 80 columns by 55 lines):

@example
XEmacs.geometry: 80x55
@end example
@noindent

since that is the syntax used with most other applications (since most
other applications have only one top-level window, unlike XEmacs).  In
general, however, the top-level shell (the unmapped ApplicationShell
widget named @samp{XEmacs} 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 @code{-geometry} command-line argument sets only the geometry of the
initial frame created by XEmacs.

A more complete explanation of geometry-handling is

@itemize @bullet
@item
The @code{-geometry} command-line option sets the @code{XEmacs.geometry}
resource, that is, the geometry of the ApplicationShell.

@item
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.

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

@item
For the first frame created, the position of the frame is taken from the
ApplicationShell (@code{XEmacs.geometry}) if it is specified, otherwise
from the geometry of the frame.

@item
For subsequent frames, the position is taken only from the frame, and
never from the ApplicationShell.
@end itemize

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.

@node Iconic Resources, Resource List, Geometry Resources, X Resources
@subsection Iconic Resources

Analogous to @code{-geometry}, the @code{-iconic} command-line option
sets the iconic flag of the ApplicationShell (@code{XEmacs.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 @code{XEmacs*FRAME-NAME.iconic} resource.

@node Resource List, Face Resources, Iconic Resources, X Resources
@subsection Resource List

XEmacs frames accept the following resources:

@table @asis
@item @code{geometry} (class @code{Geometry}): string
Initial geometry for the frame.  @xref{Geometry Resources}, for a
complete discussion of how this works.

@item @code{iconic} (class @code{Iconic}): boolean
Whether this frame should appear in the iconified state.

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

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

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

@item @code{initiallyUnmapped} (class @code{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 @code{-unmapped} command-line option.

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

@item @code{cursorColor} (class @code{CursorColor}): color-name
The color of the text cursor.

@item @code{scrollBarWidth} (class @code{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 @code{*scrollbar.width}, or the usual toolkit scrollbar resources:
@code{*XmScrollBar.width} (Motif), @code{*XlwScrollBar.width} (Lucid),
or @code{*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.

@item @code{scrollBarHeight} (class @code{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 @code{*scrollbar.height}, or the usual toolkit scrollbar resources:
@code{*XmScrollBar.height} (Motif), @code{*XlwScrollBar.height} (Lucid),
or @code{*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.

@item @code{scrollBarPlacement} (class @code{ScrollBarPlacement}): string
Where the horizontal and vertical scrollbars should be positioned.  This
should be one of the four strings @samp{BOTTOM_LEFT},
@samp{BOTTOM_RIGHT}, @samp{TOP_LEFT}, and @samp{TOP_RIGHT}.  Default is
@samp{BOTTOM_RIGHT} for the Motif and Lucid scrollbars and
@samp{BOTTOM_LEFT} for the Athena scrollbars.

@item @code{topToolBarHeight} (class @code{TopToolBarHeight}): integer
@itemx @code{bottomToolBarHeight} (class @code{BottomToolBarHeight}): integer
@itemx @code{leftToolBarWidth} (class @code{LeftToolBarWidth}): integer
@itemx @code{rightToolBarWidth} (class @code{RightToolBarWidth}): integer
Height and width of the four possible toolbars.

@item @code{topToolBarShadowColor} (class @code{TopToolBarShadowColor}): color-name
@itemx @code{bottomToolBarShadowColor} (class @code{BottomToolBarShadowColor}): color-name
Color of the top and bottom shadows for the toolbars.  NOTE: These resources
do @emph{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.

@item @code{topToolBarShadowPixmap} (class @code{TopToolBarShadowPixmap}): pixmap-name
@itemx @code{bottomToolBarShadowPixmap} (class @code{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 @emph{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.

@item @code{toolBarShadowThickness} (class @code{ToolBarShadowThickness}): integer
Thickness of the shadows around the toolbars, in pixels.

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

@item @code{bellVolume} (class @code{BellVolume}): integer
Volume of the audible beep.

@item @code{useBackingStore} (class @code{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.
@end table

XEmacs devices accept the following resources:

@table @asis
@item @code{textPointer} (class @code{Cursor}): cursor-name
The cursor to use when the mouse is over text.  This resource is used to
initialize the variable @code{x-pointer-shape}.

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

@item @code{spacePointer} (class @code{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 @code{x-nontext-pointer-shape}.

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

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

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

@item @code{pointerColor} (class @code{Foreground}): color-name
@itemx @code{pointerBackground} (class @code{Background}): color-name
The foreground and background colors of the mouse cursor.  These
resources are used to initialize the variables
@code{x-pointer-foreground-color} and @code{x-pointer-background-color}.
@end table

@node Face Resources, Widgets, Resource List, X Resources
@subsection Face Resources

The attributes of faces are also per-frame. They can be specified as:

@example
XEmacs.FACE_NAME.parameter: value
@end example
@noindent

or

@example
XEmacs*FRAME_NAME.FACE_NAME.parameter: value
@end example
@noindent

Faces accept the following resources:

@table @asis
@item @code{attributeFont} (class @code{AttributeFont}): font-name
The font of this face.

@item @code{attributeForeground} (class @code{AttributeForeground}): color-name
@itemx @code{attributeBackground} (class @code{AttributeBackground}): color-name
The foreground and background colors of this face.

@item @code{attributeBackgroundPixmap} (class @code{AttributeBackgroundPixmap}): file-name
The name of an @sc{xbm} file (or @sc{xpm} file, if your version of XEmacs
supports @sc{xpm}), to use as a background stipple.

@item @code{attributeUnderline} (class @code{AttributeUnderline}): boolean
Whether text in this face should be underlined.
@end table

All text is displayed in some face, defaulting to the face named
@code{default}.  To set the font of normal text, use
@code{XEmacs*default.attributeFont}. To set it in the frame named
@code{fred}, use @code{XEmacs*fred.default.attributeFont}.

These are the names of the predefined faces:

@table @code
@item default
Everything inherits from this.

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

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

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

@item 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.

@item 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.

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

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

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

@item info-node
This is the face of info menu items.  If unspecified, it is copied from
@code{bold-italic}.

@item info-xref
This is the face of info cross-references.  If unspecified, it is copied
from @code{bold}. (Note that, when the mouse passes over a
cross-reference, the cross-reference's face is determined from a
combination of the @code{info-xref} and @code{highlight} faces.)
@end table

Other packages might define their own faces; to see a list of all faces,
use any of the interactive face-manipulation commands such as
@code{set-face-font} and type @samp{?} when you are prompted for the
name of a face.

If the @code{bold}, @code{italic}, and @code{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

@example
*-courier-medium-r-*-*-*-120-*-*-*-*-*-*
@end example
@noindent

All X fonts can be referred to via XLFD-style names, and you should use
those forms.  See the man pages for @samp{X(1)}, @samp{xlsfonts(1)}, and
@samp{xfontsel(1)}.

If you use any of the other, less strict font name formats, some of which
look like

@example
lucidasanstypewriter-12
fixed
9x13
@end example

then XEmacs won't be able to guess the names of the bold and italic
versions, and on a build with internationalization support, it will
refuse to use them.  (Since only the XLFD form includes information as
to which character set the font coverage.)

If it is very important to you to use the short form names, you can
override this for ASCII, and for ASCII alone, by passing the
@samp{FORCE} argument to @samp{set-charset-registries}, and specifying
an empty string as one of the charset registries. 

@node Widgets, Menubar Resources, Face Resources, X Resources
@subsection 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:

@example
INVOCATION-NAME            "shell"       "container"     FRAME-NAME
x-emacs-application-class  "EmacsShell"  "EmacsManager"  "EmacsFrame"
@end example

where INVOCATION-NAME is the terminal component of the name of the
XEmacs executable (usually @samp{xemacs}), and
@samp{x-emacs-application-class} is generally @samp{XEmacs}.

@node Menubar Resources, , Widgets, X Resources
@subsection Menubar Resources

As the menubar is implemented as a widget which is not a part of XEmacs
proper, it does not use the face mechanism for specifying fonts and
colors: It uses whatever resources are appropriate to the type of widget
which is used to implement it.

If XEmacs was compiled to use only the Lucid Motif-lookalike menu widgets,
then one way to specify the font of the menubar would be

@example
XEmacs*menubar*font: *-courier-medium-r-*-*-*-120-*-*-*-*-*-*
@end example

If both the Lucid Motif-lookalike menu widgets and X Font Sets are
configured to allow multilingual menubars, then one uses

@example
*menubar*FontSet:       -*-helvetica-bold-r-*-*-*-120-*-*-*-*-iso8859-*, \
                        -*-*-*-*-*-*-*-120-*-jisx0208.1983-0
@end example

That would specify fonts for a Japanese menubar.  Specifying only one
XLFD is acceptable; specifying more than one for a given registry
(language) is also allowed.  When X Font Sets are configured, some .font
resources (eg, menubars) are ignored in favor of the corresponding
.fontSet resources.

If the Motif library is being used, then one would have to use

@example
XEmacs*menubar*fontList: *-courier-medium-r-*-*-*-120-*-*-*-*-*-*
@end example

because the Motif library uses the @code{fontList} resource name instead
of @code{font}, which has subtly different semantics.

The same is true of the scrollbars: They accept whichever resources are
appropriate for the toolkit in use.
