Other Customizations
********************

You can modify the behavior of Emacs in minor ways permanently by putting your changes in your init.el file. This file contains Lisp function call expressions. Each of these expressions will consist of a function name followed by arguments, all surrounded by parentheses. For example, to turn on the auto-fill-mode (i.e. break lines automatically when they become too long) , put the following  line in your init.el file:

     (add-hook 'text-mode-hook
             '(lambda() (auto-fill-mode 1)))

Emacs has a function named "turn-on-auto-fill" which is defined as "(lambda() (auto-fill-mode 1))". Therefore you can also write the above as:

     (add-hook 'text-mode-hook 'turn-on-auto-fill)

Emacs provides a number of hooks for the sake of customization. The hook variables contain list of functions to be called with no arguments. To turn on the auto-fill-mode, add the appropriate hook as shown in the example above.

Similarly, to enable the "font-lock mode" which displays your program in different fonts and colors(see Modes), put the following in your init.el file. The comments above the statement explain what the statements do.

     ;;; enables the font-lock-mode in Lisp Mode
     (add-hook 'lisp-mode-hook    'turn-on-font-lock)

     ;;; enables the font-lock-mode in Texinfo Mode
     (add-hook 'texinfo-mode-hook    'turn-on-font-lock)

     ;;; enables the font-lock mode in C Mode
     (add-hook 'c-mode-hook          'turn-on-font-lock)

To turn on the font-lock mode in other Major Modes like emacs-lisp, just put the name of the mode with "-hook" appended to it as the middle parameter in the above examples. You can also select the color that the functions, comments or other keywords  should be displayed in :

     ;;; the function names will now be displayed in blue color
     (set-face-foreground 'font-lock-function-name-face "blue")

     ;;; the comments will be displayed in forest green
      (set-face-foreground 'font-lock-comment-face "forest green")

For other customizations regarding the font-lock face, look at the file /usr/local/lib/xemacs-VERSION/etc/sample.init.el.

Other Customizations
====================

In XEmacs, variables are used for internal record-keeping and customizations. There are some variables called "options" which you can use for customizations. To examine a variable use:

     ;;; print the value and documentation of the variable, use either of the
     ;;; following commands
     C-h v
     M-x describe variable

After you type any of the above commands, you will be prompted for a variable name in the echo area. Type in the name of the variable, for example, type  CASE-FOLD-SEARCH RET Your window will split into two and you will see the following message in that window:

     case-fold-search's value is t
     This value is specific to the current buffer.

     Documentation:
     *Non-nil if searches should ignore case.
     Automatically becomes buffer-local when set in any fashion.

Since this variable's value is 't' searches will ignore case. If you want case-sensitive-search (i.e. if you are searching for "Foo" and you do not want "foo" to be included in the search, you need to set this variable to "nil". In order to do that, use:

     M-x set-variable

Emacs will prompt you for the variable which you wish to set. Type in "case-fold-search" and hit RET. You will see the following message:

     Set case-fold-search to value:

Type "nil" and hit RET.  Now if you again use M-x describe variable , you will see that the new value of case-fold-search will be "nil" and your searches will be case-sensitive. This will be effective only for that Emacs session. If you want to change the value of a variable permanently put the following statement in your init.el file :

     (setq case-fold-search nil)

This statement will make searches case-sensitive only in the current buffer which is the init.el file. This will not be very useful. To make searches case-sensitive globally in all buffers, use:

     (setq-default case-fold-search nil)

If you want to change the value of any other variable, use :

     (setq <variable-name> <new value>)

"setq" will assign the "new value" to the "variable-name" .

If you want a list of the "options" i.e. the variables available for customization type:

     ;;; displays a buffer listing names, values and documentation of options
     M-x list-options

     ;;; displays options and allows you to edit those list of options
     M-x edit-options

Try these options. If you are using edit-options to edit a variable, just point at the variable you wish to edit and use one of the following commands:

1
     Set the value of the variable to t (non-nil).

0
     Set the value of the variable to nil.

n
     Move to the next variable.

p
     Move to the previous variable.

There are some other options available to make the value of a variable local to a buffer and then to switch to its global value. You can also have a local variables list in a file which specifies the values to use for certain Emacs variables when you edit that file. See Variables (XEmacs User's Manual), for information on these options.

Init File Examples
==================

For customizing Emacs, you need to put Lisp expressions in your init.el file. The following are some useful Lisp expressions. If you find any of them useful, just type them in your init.el file:

  * The following expression will make TAB in C mode insert a real tab character if the cursor or point is in the middle of the line. Now hitting the TAB key will indent a line only if the cursor is at the left margin or in the line's indentation:

          (setq c-tab-always-indent nil)

     The value of the variable C-TAB-ALWAYS-INDENT is usually t for true. When this variable is true, then hitting the TAB key always indents the current line.

  * This expression will turn on the AUTO-FILL-MODE when you are in text mode:

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

     This mode will automatically break lines when you type a space so that the lines don't become too long. The length of the lines is controlled by the variable FILL-COLUMN. You can set this variable to a value you wish. Look at the documentation for this variable to see its default value. To change the value to 75 for example, use:

          (setq-default fill-column 75)

     This will change the value of this variable globally.

  * The following expression will enable the use of EVAL-EXPRESSION without confirmation:

          (put 'eval-expression 'disabled nil)

     Now when you use EVAL-EXPRESSION, it will print the value of the expression you specify in the echo area without confirming with you.

  * This expression will remove the binding of C-x C-c, because its easy to hit this key by mistake and you will exit Emacs unintentionally. You can use the Exit Emacs option from the File menu to exit Emacs.

          (global-set-key "\C-x\C-c" nil)

     Now if you type C-x C-c, you won't exit Emacs.

  * The following expression will make the BACKSPACE and the DEL key work in the same manner:

          (global-set-key 'backspace [delete])

  * This expression will make searches case sensitive:

          (setq-default case-fold-search nil)

     If we use "setq" instead of "setq-default" then searches will be case-sensitive only in the current buffer's local value. In this case the buffer would be the init.el file. Since this would not be too helpful and we want to have case-sensitive searches in all buffers, we have to use "setq-default".

  * This expression will enable the font-lock mode when you are using texinfo mode:

          (add-hook 'texinfo-mode-hook 'turn-on-font-lock)

     See Minor Modes, for information on font-lock mode.

  * Rebinds the key C-x l to run the function make-symbolic-link:

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

     We use the single quote before "make-symbolic-link" because its a function name. You can also use the following expression which does the same thing:

          (define-key global-map "C-xl" 'make-symbolic-link)

  * The following expression will bind C-x l to run the function make-symbolic-link in C mode only:

          (define-key c-mode-map "C-xl" 'make-symbolic-link)

     Instead of binding C-xl to run make-symbolic-link, you can bind the F1 key to run this function:

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

     Here, you have to use lower case for naming function keys like F1.

  * You can bind the function undo i.e. C-x u to any key, for example to F2:

          (global-set-key 'f2 'undo)

  * The following statement will display the current time in the modeline of the buffer:

          (display-time)

  * This displays the current line number on which the cursor is present in the modeline:

          (setq line-number-mode t)

  * If you don't want the text to be highlighted when you use commands for marking regions so as to use the kill and yank commands later, you can use the following expression in your init.el file:

          (setq zmacs-regions nil)

     Now if you use a command like C-x C-p (mark-page), the text will not be highlighted.

  * To control the number of buffers listed when you select the Buffers menu, you need to set the variable BUFFERS-MENU-MAX-SIZE to whatever value you wish. For example, if you want 20 buffers to be listed when you select Buffers use:

          (setq buffers-menu-max-size 20)

  * If you want the window title area to display the full directory/name of the current buffer's file, and not just the name, use:

          (setq frame-title-format "%S: %f")

  * To get rid of the menu, use :

          (set-menubar nil)

  * If you want an extensive menu-bar use the following expression in your init.el file.

          (load "big-menubar")

     If you want to write your own menus, you can look at some of the examples in /usr/local/lib/xemacs-VERSION/lisp/packages/big-menubar.el file.

For more information on initializing your init.el file, see Init File (XEmacs User's Manual). You should also look at /usr/local/lib/xemacs-VERSION/etc/sample.init.el, which is a sample init.el file. It contains some of the commonly desired customizations in Emacs.