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2011-01-15 Aidan Kehoe <kehoea@parhasard.net>
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author | Aidan Kehoe <kehoea@parhasard.net> |
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date | Sat, 15 Jan 2011 17:24:06 +0000 |
parents | 5502045ec510 |
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@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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @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 @comment node-name, next, previous, up @node Faces @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:: @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 @section 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! @c #### Make these @urlref's!! As of mid-2005, we have added support for the @file{Xft} library, which provides a more robust @emph{font configuration} mechanism via Keith Packard's @file{fontconfig} library; improved glyph rendering, including antialiasing, via the @file{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. @subheading 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. @subheading 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. @subheading 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. @subheading 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. @subheading 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. @subheading 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. @subheading 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 @subheading 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 @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 @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 @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 @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 @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 @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 @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 @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.