+File: xemacs.info, Node: Minor Modes, Next: Variables, Up: Customization
+
+Minor Modes
+===========
+
+ Minor modes are options which you can use or not. For example, Auto
+Fill mode is a minor mode in which <SPC> breaks lines between words as
+you type. All the minor modes are independent of each other and of the
+selected major mode. Most minor modes inform you in the mode line when
+they are on; for example, `Fill' in the mode line means that Auto Fill
+mode is on.
+
+ Append `-mode' to the name of a minor mode to get the name of a
+command function that turns the mode on or off. Thus, the command to
+enable or disable Auto Fill mode is called `M-x auto-fill-mode'. These
+commands are usually invoked with `M-x', but you can bind keys to them
+if you wish. With no argument, the function turns the mode on if it was
+off and off if it was on. This is known as "toggling". A positive
+argument always turns the mode on, and an explicit zero argument or a
+negative argument always turns it off.
+
+ Auto Fill mode allows you to enter filled text without breaking lines
+explicitly. Emacs inserts newlines as necessary to prevent lines from
+becoming too long. *Note Filling::.
+
+ Overwrite mode causes ordinary printing characters to replace
+existing text instead of moving it to the right. For example, if point
+is in front of the `B' in `FOOBAR', and you type a `G' in Overwrite
+mode, it changes to `FOOGAR', instead of `FOOGBAR'.
+
+ Abbrev mode allows you to define abbreviations that automatically
+expand as you type them. For example, `amd' might expand to `abbrev
+mode'. *Note Abbrevs::, for full information.
+
+\1f
+File: xemacs.info, Node: Variables, Next: Keyboard Macros, Prev: Minor Modes, Up: Customization
+
+Variables
+=========
+
+ A "variable" is a Lisp symbol which has a value. Variable names can
+contain any characters, but by convention they are words separated by
+hyphens. A variable can also have a documentation string, which
+describes what kind of value it should have and how the value will be
+used.
+
+ Lisp allows any variable to have any kind of value, but most
+variables that Emacs uses require a value of a certain type. Often the
+value has to be a string or a number. Sometimes we say that a certain
+feature is turned on if a variable is "non-`nil'," meaning that if the
+variable's value is `nil', the feature is off, but the feature is on
+for any other value. The conventional value to turn on the
+feature--since you have to pick one particular value when you set the
+variable--is `t'.
+
+ Emacs uses many Lisp variables for internal recordkeeping, as any
+Lisp program must, but the most interesting variables for you are the
+ones that exist for the sake of customization. Emacs does not
+(usually) change the values of these variables; instead, you set the
+values, and thereby alter and control the behavior of certain Emacs
+commands. These variables are called "options". Most options are
+documented in this manual and appear in the Variable Index (*note
+Variable Index::).
+
+ One example of a variable which is an option is `fill-column', which
+specifies the position of the right margin (as a number of characters
+from the left margin) to be used by the fill commands (*note 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.
+
+\1f
+File: xemacs.info, Node: Examining, Next: Easy Customization, Up: Variables
+
+Examining and Setting Variables
+-------------------------------
+
+`C-h v'
+`M-x describe-variable'
+ Print the value and documentation of a variable.
+
+`M-x set-variable'
+ Change the value of a variable.
+
+ To examine the value of a single variable, use `C-h v'
+(`describe-variable'), which reads a variable name using the
+minibuffer, with completion. It prints both the value and the
+documentation of the variable.
+
+ C-h v fill-column <RET>
+
+prints something like:
+
+ fill-column's value is 75
+
+ Documentation:
+ *Column beyond which automatic line-wrapping should happen.
+ Automatically becomes local when set in any fashion.
+
+The star at the beginning of the documentation indicates that this
+variable is an option. `C-h v' is not restricted to options; it allows
+any variable name.
+
+ If you know which option you want to set, you can use `M-x
+set-variable' to set it. This prompts for the variable name in the
+minibuffer (with completion), and then prompts for a Lisp expression
+for the new value using the minibuffer a second time. For example,
+
+ M-x set-variable <RET> fill-column <RET> 75 <RET>
+
+sets `fill-column' to 75, as if you had executed the Lisp expression
+`(setq fill-column 75)'.
+
+ Setting variables in this way, like all means of customizing Emacs
+except where explicitly stated, affects only the current Emacs session.
+
+\1f
+File: xemacs.info, Node: Easy Customization, Next: Edit Options, Prev: Examining, Up: Variables
+
+Easy Customization Interface
+----------------------------
+
+ A convenient way to find the user option variables that you want to
+change, and then change them, is with `M-x customize'. This command
+creates a "customization buffer" with which you can browse through the
+Emacs user options in a logically organized structure, then edit and
+set their values. You can also use the customization buffer to save
+settings permanently. (Not all Emacs user options are included in this
+structure as of yet, but we are adding the rest.)
+
+* 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.
+
+\1f
+File: xemacs.info, Node: Customization Groups, Next: Changing an Option, Up: Easy Customization
+
+Customization Groups
+....................
+
+ For customization purposes, user options are organized into "groups"
+to help you find them. Groups are collected into bigger groups, all
+the way up to a master group called `Emacs'.
+
+ `M-x customize' creates a customization buffer that shows the
+top-level `Emacs' group and the second-level groups immediately under
+it. It looks like this, in part:
+
+ /- Emacs group: ---------------------------------------------------\
+ [State]: visible group members are all at standard settings.
+ Customization of the One True Editor.
+ See also [Manual].
+
+ [Open] Editing group
+ Basic text editing facilities.
+
+ [Open] External group
+ Interfacing to external utilities.
+
+ MORE SECOND-LEVEL GROUPS
+
+ \- Emacs group end ------------------------------------------------/
+
+This says that the buffer displays the contents of the `Emacs' group.
+The other groups are listed because they are its contents. But they
+are listed differently, without indentation and dashes, because _their_
+contents are not included. Each group has a single-line documentation
+string; the `Emacs' group also has a `[State]' line.
+
+ Most of the text in the customization buffer is read-only, but it
+typically includes some "editable fields" that you can edit. There are
+also "active fields"; this means a field that does something when you
+"invoke" it. To invoke an active field, either click on it with
+`Mouse-1', or move point to it and type <RET>.
+
+ For example, the phrase `[Open]' that appears in a second-level
+group is an active field. Invoking the `[Open]' field for a group
+opens up a new customization buffer, which shows that group and its
+contents. This field is a kind of hypertext link to another group.
+
+ The `Emacs' group does not include any user options itself, but
+other groups do. By examining various groups, you will eventually find
+the options and faces that belong to the feature you are interested in
+customizing. Then you can use the customization buffer to set them.
+
+ You can view the structure of customization groups on a larger scale
+with `M-x customize-browse'. This command creates a special kind of
+customization buffer which shows only the names of the groups (and
+options and faces), and their structure.
+
+ In this buffer, you can show the contents of a group by invoking
+`[+]'. When the group contents are visible, this button changes to
+`[-]'; invoking that hides the group contents.
+
+ Each group, option or face name in this buffer has an active field
+which says `[Group]', `[Option]' or `[Face]'. Invoking that active
+field creates an ordinary customization buffer showing just that group
+and its contents, just that option, or just that face. This is the way
+to set values in it.
+
+\1f
+File: xemacs.info, Node: Changing an Option, Next: Face Customization, Prev: Customization Groups, Up: Easy Customization
+
+Changing an Option
+..................
+
+ Here is an example of what a user option looks like in the
+customization buffer:
+
+ Kill Ring Max: [Hide] 30
+ [State]: this option is unchanged from its standard setting.
+ Maximum length of kill ring before oldest elements are thrown away.
+
+ The text following `[Hide]', `30' in this case, indicates the
+current value of the option. If you see `[Show]' instead of `[Hide]',
+it means that the value is hidden; the customization buffer initially
+hides values that take up several lines. Invoke `[Show]' to show the
+value.
+
+ The line after the option name indicates the "customization state"
+of the option: in the example above, it says you have not changed the
+option yet. The word `[State]' at the beginning of this line is
+active; you can get a menu of various operations by invoking it with
+`Mouse-1' or <RET>. These operations are essential for customizing the
+variable.
+
+ The line after the `[State]' line displays the beginning of the
+option's documentation string. If there are more lines of
+documentation, this line ends with `[More]'; invoke this to show the
+full documentation string.
+
+ To enter a new value for `Kill Ring Max', move point to the value
+and edit it textually. For example, you can type `M-d', then insert
+another number.
+
+ When you begin to alter the text, you will see the `[State]' line
+change to say that you have edited the value:
+
+ [State]: you have edited the value as text, but not set the option.
+
+ Editing the value does not actually set the option variable. To do
+that, you must "set" the option. To do this, invoke the word `[State]'
+and choose `Set for Current Session'.
+
+ The state of the option changes visibly when you set it:
+
+ [State]: you have set this option, but not saved it for future sessions.
+
+ You don't have to worry about specifying a value that is not valid;
+setting the option checks for validity and will not really install an
+unacceptable value.
+
+ While editing a value or field that is a file name, directory name,
+command name, or anything else for which completion is defined, you can
+type `M-<TAB>' (`widget-complete') to do completion.
+
+ Some options have a small fixed set of possible legitimate values.
+These options don't let you edit the value textually. Instead, an
+active field `[Value Menu]' appears before the value; invoke this field
+to edit the value. For a boolean "on or off" value, the active field
+says `[Toggle]', and it changes to the other value. `[Value Menu]' and
+`[Toggle]' edit the buffer; the changes take effect when you use the
+`Set for Current Session' operation.
+
+ Some options have values with complex structure. For example, the
+value of `load-path' is a list of directories. Here is how it appears
+in the customization buffer:
+
+ Load Path:
+ [INS] [DEL] [Current dir?]: /usr/local/share/emacs/19.34.94/site-lisp
+ [INS] [DEL] [Current dir?]: /usr/local/share/emacs/site-lisp
+ [INS] [DEL] [Current dir?]: /usr/local/share/emacs/19.34.94/leim
+ [INS] [DEL] [Current dir?]: /usr/local/share/emacs/19.34.94/lisp
+ [INS] [DEL] [Current dir?]: /build/emacs/e19/lisp
+ [INS] [DEL] [Current dir?]: /build/emacs/e19/lisp/gnus
+ [INS]
+ [State]: this item has been changed outside the customization buffer.
+ List of directories to search for files to load....
+
+Each directory in the list appears on a separate line, and each line has
+several editable or active fields.
+
+ You can edit any of the directory names. To delete a directory from
+the list, invoke `[DEL]' on that line. To insert a new directory in
+the list, invoke `[INS]' at the point where you want to insert it.
+
+ You can also invoke `[Current dir?]' to switch between including a
+specific named directory in the path, and including `nil' in the path.
+(`nil' in a search path means "try the current directory.")
+
+ Two special commands, <TAB> and `S-<TAB>', are useful for moving
+through the customization buffer. <TAB> (`widget-forward') moves
+forward to the next active or editable field; `S-<TAB>'
+(`widget-backward') moves backward to the previous active or editable
+field.
+
+ Typing <RET> on an editable field also moves forward, just like
+<TAB>. The reason for this is that people have a tendency to type
+<RET> when they are finished editing a field. If you have occasion to
+insert a newline in an editable field, use `C-o' or `C-q C-j',
+
+ Setting the option changes its value in the current Emacs session;
+"saving" the value changes it for future sessions as well. This works
+by writing code into your init file so as to set the option variable
+again each time you start Emacs. *Note Init File::. To save the
+option, invoke `[State]' and select the `Save for Future Sessions'
+operation.
+
+ You can also restore the option to its standard value by invoking
+`[State]' and selecting the `Reset' operation. There are actually
+three reset operations:
+
+`Reset to Current'
+ If you have made some modifications and not yet set the option,
+ this restores the text in the customization buffer to match the
+ actual value.
+
+`Reset to Saved'
+ This restores the value of the option to the last saved value, and
+ updates the text accordingly.
+
+`Reset to Standard Settings'
+ This sets the option to its standard value, and updates the text
+ accordingly. This also eliminates any saved value for the option,
+ so that you will get the standard value in future Emacs sessions.
+
+ The state of a group indicates whether anything in that group has
+been edited, set or saved. You can select `Set for Current Session',
+`Save for Future Sessions' and the various kinds of `Reset' operation
+for the group; these operations on the group apply to all options in
+the group and its subgroups.
+
+ Near the top of the customization buffer there are two lines
+containing several active fields:
+
+ [Set] [Save] [Reset] [Done]
+
+Invoking `[Done]' buries this customization buffer. Each of the other
+fields performs an operation--set, save or reset--on each of the items
+in the buffer that could meaningfully be set, saved or reset.
+
+\1f
+File: xemacs.info, Node: Face Customization, Next: Specific Customization, Prev: Changing an Option, Up: Easy Customization
+
+Customizing Faces
+.................
+
+ In addition to user options, some customization groups also include
+faces. When you show the contents of a group, both the user options and
+the faces in the group appear in the customization buffer. Here is an
+example of how a face looks:
+
+ Custom Changed Face: (sample)
+ [State]: this face is unchanged from its standard setting.
+ Face used when the customize item has been changed.
+ Parent groups: [Custom Magic Faces]
+ Attributes: [ ] Bold: [Toggle] off (nil)
+ [ ] Italic: [Toggle] off (nil)
+ [ ] Underline: [Toggle] off (nil)
+ [ ] Foreground: white (sample)
+ [ ] Background: blue (sample)
+ [ ] Inverse: [Toggle] off (nil)
+ [ ] Stipple:
+ [ ] Font Family:
+ [ ] Size:
+ [ ] Strikethru: off
+
+ Each face attribute has its own line. The `[X]' field before the
+attribute name indicates whether the attribute is "enabled"; `X' means
+that it is. You can enable or disable the attribute by invoking that
+field. When the attribute is enabled, you can change the attribute
+value in the usual ways.
+
+ Setting, saving and resetting a face work like the same operations
+for options (*note Changing an Option::).
+
+ A face can specify different appearances for different types of
+display. For example, a face can make text red on a color display, but
+use a bold font on a monochrome display. To specify multiple
+appearances for a face, select `Show Display Types' in the menu you get
+from invoking `[State]'.
+
+\1f
+File: xemacs.info, Node: Specific Customization, Prev: Face Customization, Up: Easy Customization
+
+Customizing Specific Items
+..........................
+
+ Instead of finding the options you want to change by moving down
+through the structure of groups, you can specify the particular option,
+face or group that you want to customize.
+
+`M-x customize-option <RET> OPTION <RET>'
+ Set up a customization buffer with just one option, OPTION.
+
+`M-x customize-face <RET> FACE <RET>'
+ Set up a customization buffer with just one face, FACE.
+
+`M-x customize-group <RET> GROUP <RET>'
+ Set up a customization buffer with just one group, GROUP.
+
+`M-x customize-apropos <RET> REGEXP <RET>'
+ Set up a customization buffer with all the options, faces and
+ groups that match REGEXP.
+
+`M-x customize-saved'
+ Set up a customization buffer containing all options and faces
+ that you have saved with customization buffers.
+
+`M-x customize-customized'
+ Set up a customization buffer containing all options and faces
+ that you have customized but not saved.
+
+ If you want to alter a particular user option variable with the
+customization buffer, and you know its name, you can use the command
+`M-x customize-option' and specify the option name. This sets up the
+customization buffer with just one option--the one that you asked for.
+Editing, setting and saving the value work as described above, but only
+for the specified option.
+
+ Likewise, you can modify a specific face, chosen by name, using `M-x
+customize-face'.
+
+ You can also set up the customization buffer with a specific group,
+using `M-x customize-group'. The immediate contents of the chosen
+group, including option variables, faces, and other groups, all appear
+as well. However, these subgroups' own contents start out hidden. You
+can show their contents in the usual way, by invoking `[Show]'.
+
+ To control more precisely what to customize, you can use `M-x
+customize-apropos'. You specify a regular expression as argument; then
+all options, faces and groups whose names match this regular expression
+are set up in the customization buffer. If you specify an empty regular
+expression, this includes _all_ groups, options and faces in the
+customization buffer (but that takes a long time).
+
+ If you change option values and then decide the change was a mistake,
+you can use two special commands to revisit your previous changes. Use
+`customize-saved' to look at the options and faces that you have saved.
+Use `M-x customize-customized' to look at the options and faces that
+you have set but not saved.
+
+\1f
+File: xemacs.info, Node: Edit Options, Next: Locals, Prev: Easy Customization, Up: Variables
+
+Editing Variable Values
+-----------------------
+
+`M-x list-options'
+ Display a buffer listing names, values, and documentation of all
+ options.
+
+`M-x edit-options'
+ Change option values by editing a list of options.
+
+ `M-x list-options' displays a list of all Emacs option variables in
+an Emacs buffer named `*List Options*'. Each option is shown with its
+documentation and its current value. Here is what a portion of it might
+look like:
+
+ ;; exec-path:
+ ("." "/usr/local/bin" "/usr/ucb" "/bin" "/usr/bin" "/u2/emacs/etc")
+ *List of directories to search programs to run in subprocesses.
+ Each element is a string (directory name)
+ or nil (try the default directory).
+ ;;
+ ;; fill-column:
+ 75
+ *Column beyond which automatic line-wrapping should happen.
+ Automatically becomes local when set in any fashion.
+ ;;
+
+ `M-x edit-options' goes one step further and immediately selects the
+`*List Options*' buffer; this buffer uses the major mode Options mode,
+which provides commands that allow you to point at an option and change
+its value:
+
+`s'
+ Set the variable point is in or near to a new value read using the
+ minibuffer.
+
+`x'
+ Toggle the variable point is in or near: if the value was `nil',
+ it becomes `t'; otherwise it becomes `nil'.
+
+`1'
+ Set the variable point is in or near to `t'.
+
+`0'
+ Set the variable point is in or near to `nil'.
+
+`n'
+`p'
+ Move to the next or previous variable.
+
+\1f
+File: xemacs.info, Node: Locals, Next: File Variables, Prev: Edit Options, Up: Variables
+
+Local Variables
+---------------
+
+`M-x make-local-variable'
+ Make a variable have a local value in the current buffer.
+
+`M-x kill-local-variable'
+ Make a variable use its global value in the current buffer.
+
+`M-x make-variable-buffer-local'
+ Mark a variable so that setting it will make it local to the
+ buffer that is current at that time.
+
+ You can make any variable "local" to a specific Emacs buffer. This
+means that the variable's value in that buffer is independent of its
+value in other buffers. A few variables are always local in every
+buffer. All other Emacs variables have a "global" value which is in
+effect in all buffers that have not made the variable local.
+
+ Major modes always make the variables they set local to the buffer.
+This is why changing major modes in one buffer has no effect on other
+buffers.
+
+ `M-x make-local-variable' reads the name of a variable and makes it
+local to the current buffer. Further changes in this buffer will not
+affect others, and changes in the global value will not affect this
+buffer.
+
+ `M-x make-variable-buffer-local' reads the name of a variable and
+changes the future behavior of the variable so that it automatically
+becomes local when it is set. More precisely, once you have marked a
+variable in this way, the usual ways of setting the variable will
+automatically invoke `make-local-variable' first. We call such
+variables "per-buffer" variables.
+
+ Some important variables have been marked per-buffer already. They
+include `abbrev-mode', `auto-fill-function', `case-fold-search',
+`comment-column', `ctl-arrow', `fill-column', `fill-prefix',
+`indent-tabs-mode', `left-margin',
+`mode-line-format', `overwrite-mode', `selective-display-ellipses',
+`selective-display', `tab-width', and `truncate-lines'. Some other
+variables are always local in every buffer, but they are used for
+internal purposes.
+
+ Note: the variable `auto-fill-function' was formerly named
+`auto-fill-hook'.
+
+ If you want a variable to cease to be local to the current buffer,
+call `M-x kill-local-variable' and provide the name of a variable to
+the prompt. The global value of the variable is again in effect in
+this buffer. Setting the major mode kills all the local variables of
+the buffer.
+
+ To set the global value of a variable, regardless of whether the
+variable has a local value in the current buffer, you can use the Lisp
+function `setq-default'. It works like `setq'. If there is a local
+value in the current buffer, the local value is not affected by
+`setq-default'; thus, the new global value may not be visible until you
+switch to another buffer, as in the case of:
+
+ (setq-default fill-column 75)
+
+`setq-default' is the only way to set the global value of a variable
+that has been marked with `make-variable-buffer-local'.
+
+ Programs can look at a variable's default value with `default-value'.
+This function takes a symbol as an argument and returns its default
+value. The argument is evaluated; usually you must quote it
+explicitly, as in the case of:
+
+ (default-value 'fill-column)
+
+\1f
projects / chise / xemacs-chise.git- / blobdiff