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Info file ../info/emacs, produced by Makeinfo, -*- Text -*- from input file lemacs.tex. This file documents the GNU Emacs editor. Copyright (C) 1985, 1986, 1988 Richard M. Stallman. Copyright (C) 1991, 1992 Lucid, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the sections entitled "The GNU Manifesto", "Distribution" and "GNU General Public License" are included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that the sections entitled "The GNU Manifesto", "Distribution" and "GNU General Public License" may be included in a translation approved by the author instead of in the original English. File: emacs, Node: Keystrokes, Next: Representing Keystrokes, Prev: Screen, Up: Top Keystrokes as Building Blocks of Key Sequences ============================================== Earlier versions of GNU Emacs used only the ASCII character set, which defines 128 different character codes. Some of these codes are assigned graphic symbols like `a' and `='; the rest are control characters, such as `Control-a' (also called `C-a'). `C-a' means you hold down the CTRL key and then press `a'. Keybindings in Lucid GNU Emacs are no longer restricted to the set of keystrokes that can be represented in ASCII. Emacs can now tell the difference between, for example, `Control-h', `Control-Shift-h', and `Backspace'. A keystroke is like a piano chord: you get it by simultaneously striking several keys. To be more precise, a keystroke consists of a possibly empty set of modifiers followed by a single "keysym". The set of modifiers is small; it consists of `Control', `Meta', `Super', `Hyper', and `Shift'. The rest of the keys on your keyboard, along with the mouse buttons, make up the set of keysyms. A keysym is usually what is printed on the keys on your keyboard. Here is a table of some of the symbolic names for keysyms: `a,b,c...' alphabetic keys `f1,f2...' function keys `button1' left mouse button `button2' middle mouse button `button3' right mouse button `button1up' upstroke on the left mouse button `button2up' upstroke on the middle mouse button `button3up' upstroke on the right mouse button `return' Return key Use the variable `keyboard-translate-table' only if you are on a dumb tty, as it cannot handle input that cannot be represented as ASCII. The value of this variable is a string used as a translate table for keyboard input or `nil'. Each character is looked up in this string and the contents used instead. If the string is of length `n', character codes `N' and up are untranslated. If you are running Emacs under X, you should do the translations with the `xmodmap' program instead. * Menu: * Representing Keystrokes:: Using lists of modifiers and keysyms to represent keystrokes. * Key Sequences:: Combine key strokes into key sequences you can bind to commands. * String Key Sequences:: Available for upward compatibility. * Meta Key:: Using ESC to represent Meta * Super and Hyper Keys:: Adding modifier keys on certain keyboards. * Character Representation:: How characters appear in Emacs buffers. * Commands:: How commands are bound to key sequences. File: emacs, Node: Representing Keystrokes, Next: Key Sequences, Prev: Keystrokes, Up: Top Representing Keystrokes ----------------------- Lucid GNU Emacs represents keystrokes as lists. Each list consists of an arbitrary combination of modifiers followed by a single keysym at the end of the list. If the keysym corresponds to an ASCII character, you can use its character code. (A keystroke may also be represented by an event object, as returned by the `read-key-sequence' function; non-programmers need not worry about this.) The following table gives some examples of how to list representations for keystrokes. Each list consists of sets of modifiers followed by keysyms: `(control a)' Pressing CTRL and `a' simultaneously. `(control ?a)' Another way of writing the keystroke `C-a'. `(control 65)' Yet another way of writing the keystroke `C-a'. `(break)' Pressing the BREAK key. `(control meta button2up)' Release the middle mouse button, while pressing CTRL and META. Note: As you define keystrokes, you can use the `shift' key only as a modifier with characters that do not have a second keysym on the same key, such as `backspace' and `tab'. It is an error to define a keystroke using the shift modifier with keysyms such as `a' and `='. The correct forms are `A' and `+'. File: emacs, Node: Key Sequences, Next: String Key Sequences, Prev: Representing Keystrokes, Up: Keystrokes Representing Key Sequences -------------------------- A "complete key sequence" is a sequence of keystrokes that Emacs understands as a unit. Key sequences are significant because you can bind them to commands. Note that not all sequences of keystrokes are possible key sequences. In particular, the initial keystrokes in a key sequence must make up a "prefix key sequence". Emacs represents a key sequence as a vector of keystrokes. Thus, the schematic representation of a complete key sequence is as follows: [(modifier .. modifer keysym) ... (modifier .. modifier keysym)] Here are some examples of complete key sequences: `[(control c) (control a)]' Typing `C-c' followed by `C-a' `[(control c) (control 65)]' Typing `C-c' followed by `C-a'. (Using the ASCII code for the character `a') `[(control c) (break)]' Typing `C-c' followed by the `break' character. A "prefix key sequence" is the beginning of a series of longer sequences that are valid key sequences; adding any single keystroke to the end of a prefix results in a valid key sequence. For example, `control-x' is standardly defined as a prefix. Thus, there is a two-character key sequence starting with `C-x' for each valid keystroke, giving numerous possibilities. Here are some samples: * `[(control x) (c)]' * `[(control x) (control c)]' Adding one character to a prefix key does not have to form a complete key. It could make another, longer prefix. For example, `[(control x) (\4)]' is itself a prefix that leads to any number of different three-character keys, including `[(control x) (\4) (f)]', `[(control x) (\4) (b)]' and so on. It would be possible to define one of those three-character sequences as a prefix, creating a series of four-character keys, but we did not define any of them this way. By contrast, the two-character sequence `[(control f) (control k)]' is not a key, because the `(control f)' is a complete key sequence in itself. It's impossible to give `[(control f (control k)]' an independent meaning as a command as long as `(control f)' retains its meaning, because what we have is really two commands. The predefined prefix key sequences in Emacs are `(control c)', `(control x)', `(control h)', `[(control x) (\4)]', and `escape'. You can customize Emacs, and could make new prefix keys, or eliminate the default key sequences. *Note Key Bindings::. Whether a particular key sequence is valid can be changed by customization. For example, if you redefine `(control f)' as a prefix, `[(control f) (control k)]' automatically becomes a valid key sequence (complete, unless you define it as a prefix as well). Conversely, if you remove the prefix definition of `[(control x) (\4)]', `[(control x) (\4) (f)]' (or `[(control x) (\4) ANYTHING]') is no longer a valid key sequence. Note that the above paragraphs uses \4 instead of simply 4, because \4 is the symbol whose name is "4", and plain 4 is the integer 4, which would have been interpreted as the ASCII value. Another way of representing the symbol whose name is "4" is to write ?4, which would be interpreted as the number 52, which is the ASCII code for the character "4". We could therefore actually have written 52 directly but that is far less clear. File: emacs, Node: String Key Sequences, Next: Meta Key, Prev: Key Sequences, Up: Keystrokes String Key Sequences -------------------- For backward compatibility, you may also represent a key sequence using strings. For example, we have the following equivalent representations: `"\C-c\C-c"' `[(control c) (control c)]' `"\e\C-c"' `[(meta control c)]' * Menu: * Meta Key:: Assignment of the META Key * Super and Hyper Keys:: Assignment of the SUPER and HYPER Keys File: emacs, Node: Meta Key, Next: Super and Hyper Keys, Prev: String Key Sequences, Up: Keystrokes Assignment of the META Key -------------------------- Not all terminals have the complete set of modifiers. Terminals that have a Meta key allow you to type Meta characters by just holding that key down. To type `Meta-a', hold down META and press `a'. On those terminals, the META key works like the SHIFT key. Such a key is not always labeled META, however, as this function is often a special option for a key with some other primary purpose. If there is no META key, you can still type Meta characters using two-character sequences starting with ESC. To enter `M-a', you could type `ESC a'. To enter `C-M-a', you would type `ESC C-a'. ESC is allowed on terminals with Meta keys, too, in case you have formed a habit of using it. If you are running under X and do not have a Meta key, it is possible to reconfigure some other key to be a Meta key. *Note Super and Hyper Keys::. Emacs believes the terminal has a META key if the variable `meta-flag' is non-`nil'. Normally this is set automatically according to the termcap entry for your terminal type. However, sometimes the termcap entry is wrong, and then it is useful to set this variable yourself. *Note Variables::, for how to do this. Note: If you are running under the X window system, the setting of the `meta-flag' variable is irrelevant. File: emacs, Node: Super and Hyper Keys, Next: Character Representation, Prev: Meta Key, Up: Keystrokes Assignment of the SUPER and HYPER Keys -------------------------------------- Most keyboards do not, by default, have SUPER or HYPER modifier keys. Under X, you can simulate the SUPER or HYPER key if you want to bind keys to sequences using `super' and `hyper'. You can use the `xmodmap' program to do this. For example, to turn your CAPS-LOCK key into a SUPER key, do the following: Create a file called `~/.xmodmap'. In this file, place the lines remove Lock = Caps_Lock keysym Caps_Lock = Super_L add Mod2 = Super_L The first line says that the key that is currently called `Caps_Lock' should no longer behave as a "lock" key. The second line says that this should now be called `Super_L' instead. The third line says that the key called `Super_L' should be a modifier key, which produces the `Mod2' modifier. To create a Meta or Hyper key instead of a Super key, replace the word "Super" above with Meta or Hyper. Just after you start up X, execute the command `xmodmap /.xmodmap'. You can add this command to the appropriate initialization file to have the command executed automatically. If you have problems, see the documentation for the `xmodmap' program. The X keyboard model is quite complicated, and explaining it is beyond the scope of this manual. File: emacs, Node: Key Bindings, Next: Syntax, Prev: Keyboard Macros, Up: Customization Customizing Key Bindings ======================== This section deals with the "keymaps" which define the bindings between keys and functions, and shows how you can customize these bindings. A command is a Lisp function whose definition provides for interactive use. Like every Lisp function, a command has a function name, 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. File: emacs, Node: Keymaps, Next: Disabling, Up: Key Bindings Keymaps ------- The bindings between characters and command functions are recorded in data structures called "keymaps". Emacs has many of these. One, the "global" keymap, defines the meanings of the single-character keys that are defined regardless of major mode. It is the value of the variable `global-map'. Each major mode has another keymap, its "local keymap", which contains overriding definitions for the single-character keys that are redefined in that mode. Each buffer records which local keymap is installed for it at any time, and the current buffer's local keymap is the only one that directly affects command execution. The local keymaps for Lisp mode, C mode, and many other major modes always exist even when not in use. They are the values of the variables `lisp-mode-map', `c-mode-map', and so on. For less frequently used major modes, the local keymap is sometimes constructed only when the mode is used for the first time in a session, to save space. There are local keymaps for the minibuffer too; they contain various completion and exit commands. * `minibuffer-local-map' is used for ordinary input (no completion). * `minibuffer-local-ns-map' is similar, except that SPC exits just like RET. This is used mainly for Mocklisp compatibility. * `minibuffer-local-completion-map' is for permissive completion. * `minibuffer-local-must-match-map' is for strict completion and for cautious completion. * `repeat-complex-command-map' is for use in `C-x ESC'. * `isearch-mode-map' contains the bindings of the special keys which are bound in the pseudo-mode entered with `C-s' and `C-r'. Finally, each prefix key has a keymap which defines the key sequences that start with it. For example, `ctl-x-map' is the keymap used for characters following a `C-x'. * `ctl-x-map' is the variable name for the map used for characters that follow `C-x'. * `help-map' is used for characters that follow `C-h'. * `esc-map' is for characters that follow ESC. All Meta characters are actually defined by this map. * `ctl-x-4-map' is for characters that follow `C-x 4'. * `mode-specific-map' is for characters that follow `C-c'. The definition of a prefix key is the keymap to use for looking up the following character. Sometimes, the definition is actually a Lisp symbol whose function definition is the following character keymap. The effect is the same, but it provides a command name for the prefix key that you can use as a description of what the prefix key is for. Thus, the binding of `C-x' is the symbol `Ctl-X-Prefix', whose function definition is the keymap for `C-x' commands, the value of `ctl-x-map'. Prefix key definitions can appear in either the global map or a local map. The definitions of `C-c', `C-x', `C-h' and ESC as prefix keys appear in the global map, so these prefix keys are always available. Major modes can locally redefine a key as a prefix by putting a prefix key definition for it in the local map. A mode can also put a prefix definition of a global prefix character such as `C-x' into its local map. This is how major modes override the definitions of certain keys that start with `C-x'. This case is special, because the local definition does not entirely replace the global one. When both the global and local definitions of a key are other keymaps, the next character is looked up in both keymaps, with the local definition overriding the global one. So, the character after the `C-x' is looked up in both the major mode's own keymap for redefined `C-x' commands and in `ctl-x-map'. If the major mode's own keymap for `C-x' commands contains `nil', the definition from the global keymap for `C-x' commands is used. * Menu: * Rebinding:: Changing Key Bindings Interactively * Programmatic Rebinding:: Changing Key Bindings Programmatically * Key Bindings Using Strings::Using Strings for Changings Key Bindings File: emacs, Node: Rebinding, Next: Programmatic Rebinding, Prev: Keymaps, Up: Keymaps Changing Key Bindings Interactively ----------------------------------- 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. `M-x global-set-key RET KEY CMD RET' Defines KEY globally to run CMD. `M-x local-set-key RET KEYS CMD RET' Defines KEY locally (in the major mode now in effect) to run CMD. `M-x local-unset-key RET KEYS RET' Removes the local binding of KEY. CMD is a symbol naming an interactively-callable function. When called interactively, KEY is the next complete key sequence that you type. When called as a function, KEY is a string, a vector of events or a vector of key-description lists as described in the the `define-key' function description. The binding goes in the current buffer's local map, which is shared with other buffers in the same major mode. The following example, M-x global-set-key RET C-f next-line RET redefines `C-f' to move down a line. The fact that CMD is read second makes it serve as a kind of confirmation for KEY. These functions offer no way to specify a particular prefix keymap as the one to redefine in, but that is not necessary, as you can include prefixes in KEY. KEY is read by reading characters one by one until they amount to a complete key (that is, not a prefix key). Thus, if you type `C-f' for KEY, Emacs enters the minibuffer immediately to read CMD. But if you type `C-x', another character is read; if that character is `4', another character is read, and so on. For example, M-x global-set-key RET C-x 4 $ spell-other-window RET redefines `C-x 4 $' to run the (fictitious) command `spell-other-window'. The most general way to modify a keymap is the function `define-key', used in Lisp code (such as your `.emacs' file). `define-key' takes three arguments: the keymap, the key to modify in it, and the new definition. *Note Init File::, for an example. `substitute-key-definition' is used similarly; it takes three arguments, an old definition, a new definition and a keymap, and redefines in that keymap all keys that were previously defined with the old definition to have the new definition instead. File: emacs, Node: Programmatic Rebinding, Next: Key Bindings Using Strings, Prev: Rebinding, Up: Keymaps Changing Key Bindings Programmatically -------------------------------------- You can use the functions `global-set-key' and `define-key' to rebind keys under program control. ``(global-set-key KEYS CMD)'' Defines KEYS globally to run CMD. ``(define-key KEYMAP KEYS DEF)'' Defines KEYS to run CMD in the keymap KEYMAP. KEYMAP is a keymap object. KEYS is the sequence of keystrokes to bind. DEF is anything that can be a key's definition: * `nil' meaning key is undefined in this keymap. * A command, that is, a Lisp function suitable for interactive calling. * A string or key sequence vector, which is treated as a keyboard macro. * A keymap to define a prefix key. * A symbol so that when the key is looked up, the symbol stands for its function definition, which should at that time be one of the above, or another symbol whose function definition is used, and so on. * A cons, `(string . defn)', meaning that DEFN is the definition (DEFN should be a valid definition in its own right). * A cons, `(keymap . char)', meaning use the definition of CHAR in map KEYMAP. For backward compatibility, Lucid GNU Emacs allows you to specify key sequences as strings. However, the preferred method is to use the representations of key sequences as vectors of keystrokes. *Note Keystrokes::, for more information about the rules for constructing key sequences. Emacs allows you to abbreviate representations for key sequences in most places where there is no ambiguity. Here are some rules for abbreviation: * The keysym by itself is equivalent to a list of just that keysym, i.e. `f1' is equivalent to `(f1)'. * A keystroke by itself is equivalent to a vector containing just that keystroke, i.e. `(control a)' is equivalent to `[(control a)]' * You can use ASCII codes for keysyms that have them. i.e. `65' is equivalent to `A'. (This is not so much an abbreviation as an alternate representation.) Here are some examples of programmatically binding keys: ;;; Bind `my-command' to f1 (global-set-key 'f1 'my-command) ;;; Bind `my-command' to `Shift-f1' (global-set-key '(shift f1) 'my-command) ;;; Bind `my-command' to `C-c Shift-f1' (global-set-key '[(control c) (shift f1)] 'my-command) ;;; Bind `my-command' to the middle mouse button. (global-set-key 'button2 'my-command) ;;; Bind `my-command' to `META CTL Right Mouse Button' ;;; in the keymap that is in force when you are running `dired'. (define-key dired-mode-map '(meta control button3) 'my-command) File: emacs, Node: Key Bindings Using Strings, Prev: Programmatic Rebinding, Up: Keymaps For backward compatibility, you can still use strings to represent key sequences. Thus you can use comands like the following: ;;; Bind `end-of-line' to `C-f' (global-set-key "\C-f" 'end-of-line) Note, however, that in some cases you may be binding more than one key sequence by using a single command. This situation can arise because in ASCII, `C-i' and TAB have the same representation. Therefore, when Emacs sees: (global-set-key "\C-i" 'end-of-line) it is unclear whether the user intended to bind `C-i' or TAB. The solution Lucid GNU Emacs adopts is to bind both of these key sequences. After binding a command to two key sequences with a form like (define-key global-map "\^X\^I" 'command-1) it is possible to redefine only one of those sequences like so: (define-key global-map [(control x) (control i)] 'command-2) (define-key global-map [(control x) tab] 'command-3) This applies only when running under a window system. If you are talking to Emacs through an ASCII-only channel, you do not get any of these features. Here is a table of pairs of key sequences that behave in a similar fashion: control h backspace control l clear control i tab control m return control j linefeed control [ escape control @ control space File: emacs, Node: Disabling, Prev: Keymaps, Up: Key Bindings Disabling Commands ------------------ Disabling a command marks it as requiring confirmation before it can be executed. The purpose of disabling a command is to prevent beginning users from executing it by accident and being confused. The direct mechanism for disabling a command is to have a non-`nil' `disabled' property on the Lisp symbol for the command. These properties are normally set by the user's `.emacs' file with Lisp expressions such as (put 'delete-region 'disabled t) If the value of the `disabled' property is a string, that string is included in the message printed when the command is used: (put 'delete-region 'disabled "Text deleted this way cannot be yanked back!\n") You can disable a command either by editing the `.emacs' file directly or with the command `M-x disable-command', which edits the `.emacs' file for you. *Note Init File::. When you attempt to invoke a disabled command interactively in Emacs, a window is displayed containing the command's name, its documentation, and some instructions on what to do next; then Emacs asks for input saying whether to execute the command as requested, enable it and execute, or cancel it. If you decide to enable the command, you are asked whether to do this permanently or just for the current session. Enabling permanently works by automatically editing your `.emacs' file. You can use `M-x enable-command' at any time to enable any command permanently. Whether a command is disabled is independent of what key is used to invoke it; it also applies if the command is invoked using `M-x'. Disabling a command has no effect on calling it as a function from Lisp programs. File: emacs, Node: Syntax, Next: Init File, Prev: Key Bindings, Up: Customization The Syntax Table ================ All the Emacs commands which parse words or balance parentheses are controlled by the "syntax table". The syntax table specifies which characters are opening delimiters, which are parts of words, which are string quotes, and so on. Actually, each major mode has its own syntax table (though sometimes related major modes use the same one) which it installs in each buffer that uses that major mode. The syntax table installed in the current buffer is the one that all commands use, so we call it "the" syntax table. A syntax table is a Lisp object, a vector of length 256 whose elements are numbers. * Menu: * Entry: Syntax Entry. What the syntax table records for each character. * Change: Syntax Change. How to change the information. File: emacs, Node: Syntax Entry, Next: Syntax Change, Prev: Syntax, Up: Syntax Information about Each Character -------------------------------- The syntax table entry for a character is a number that encodes six pieces of information: * The syntactic class of the character, represented as a small integer. * The matching delimiter, for delimiter characters only. The matching delimiter of `(' is `)', and vice versa. * A flag saying whether the character is the first character of a two-character comment starting sequence. * A flag saying whether the character is the second character of a two-character comment starting sequence. * A flag saying whether the character is the first character of a two-character comment ending sequence. * A flag saying whether the character is the second character of a two-character comment ending sequence. The syntactic classes are stored internally as small integers, but are usually described to or by the user with characters. For example, `(' is used to specify the syntactic class of opening delimiters. Here is a table of syntactic classes, with the characters that specify them. ` ' The class of whitespace characters. `w' The class of word-constituent characters. `_' The class of characters that are part of symbol names but not words. This class is represented by `_' because the character `_' has this class in both C and Lisp. `.' The class of punctuation characters that do not fit into any other special class. `(' The class of opening delimiters. `)' The class of closing delimiters. `'' The class of expression-adhering characters. These characters are part of a symbol if found within or adjacent to one, and are part of a following expression if immediately preceding one, but are like whitespace if surrounded by whitespace. `"' The class of string-quote characters. They match each other in pairs, and the characters within the pair all lose their syntactic significance except for the `\' and `/' classes of escape characters, which can be used to include a string-quote inside the string. `$' The class of self-matching delimiters. This is intended for TeX's `$', which is used both to enter and leave math mode. Thus, a pair of matching `$' characters surround each piece of math mode TeX input. A pair of adjacent `$' characters act like a single one for purposes of matching `/' The class of escape characters that always just deny the following character its special syntactic significance. The character after one of these escapes is always treated as alphabetic. `\' The class of C-style escape characters. In practice, these are treated just like `/'-class characters, because the extra possibilities for C escapes (such as being followed by digits) have no effect on where the containing expression ends. `<' The class of comment-starting characters. Only single-character comment starters (such as `;' in Lisp mode) are represented this way. `>' The class of comment-ending characters. Newline has this syntax in Lisp mode. The characters flagged as part of two-character comment delimiters can have other syntactic functions most of the time. For example, `/' and `*' in C code, when found separately, have nothing to do with comments. The comment-delimiter significance overrides when the pair of characters occur together in the proper order. Only the list and sexp commands use the syntax table to find comments; the commands specifically for comments have other variables that tell them where to find comments. And the list and sexp commands notice comments only if `parse-sexp-ignore-comments' is non-`nil'. This variable is set to `nil' in modes where comment-terminator sequences are liable to appear where there is no comment; for example, in Lisp mode where the comment terminator is a newline but not every newline ends a comment. File: emacs, Node: Syntax Change, Prev: Syntax Entry, Up: Syntax Altering Syntax Information --------------------------- It is possible to alter a character's syntax table entry by storing a new number in the appropriate element of the syntax table, but it would be hard to determine what number to use. Emacs therefore provides a command that allows you to specify the syntactic properties of a character in a convenient way. `M-x modify-syntax-entry' is the command to change a character's syntax. It can be used interactively, and is also used by major modes to initialize their own syntax tables. Its first argument is the character to change. The second argument is a string that specifies the new syntax. When called from Lisp code, there is a third, optional argument, which specifies the syntax table in which to make the change. If not supplied, or if this command is called interactively, the third argument defaults to the current buffer's syntax table. 1. The first character in the string specifies the syntactic class. It is one of the characters in the previous table (*note Syntax Entry::.). 2. The second character is the matching delimiter. For a character that is not an opening or closing delimiter, this should be a space, and may be omitted if no following characters are needed. 3. The remaining characters are flags. The flag characters allowed are `1' Flag this character as the first of a two-character comment starting sequence. `2' Flag this character as the second of a two-character comment starting sequence. `3' Flag this character as the first of a two-character comment ending sequence. `4' Flag this character as the second of a two-character comment ending sequence. Use `C-h s' (`describe-syntax') to display a description of the contents of the current syntax table. The description of each character includes both the string you have to pass to `modify-syntax-entry' to set up that character's current syntax, and some English to explain that string if necessary. File: emacs, Node: Init File, Next: Audible Bell, Prev: Syntax, Up: Customization The Init File, .emacs ===================== When you start Emacs, it normally loads the file `.emacs' in your home directory. This file, if it exists, should contain Lisp code. It is called your initialization file or "init file". Use the command line switches `-q' and `-u' to tell Emacs whether to load an init file (*note Entering Emacs::.). When the `.emacs' file is read, the variable `init-file-user' says which users init file it is. The value may be the null string or a string containing a user's name. If the value is a null string, it means that the init file was taken from the user that originally logged in. In all cases, `(concat "~" init-file-user "/")' evaluates to the directory name of the directory where the `.emacs' file was looked for. At some sites, there is a "default init file", which is the library named `default.el', found via the standard search path for libraries. The Emacs distribution contains no such library; your site may create one for local customizations. If this library exists, it is loaded whenever you start Emacs. But your init file, if any, is loaded first; if it sets `inhibit-default-init' non-`nil', then `default' is not loaded. If you have a large amount of code in your `.emacs' file, you should move it into another file named `SOMETHING.el', byte-compile it (*note Lisp Libraries::.), and load that file from your `.emacs' file using `load'. * 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. File: emacs, Node: Init Syntax, Next: Init Examples, Prev: Init File, Up: Init File Init File Syntax ---------------- The `.emacs' file contains one or more Lisp function call expressions. Each consists of a function name followed by arguments, all surrounded by parentheses. For example, `(setq fill-column 60)' represents a call to the function `setq' which is used to set the variable `fill-column' (*note Filling::.) to 60. The second argument to `setq' is an expression for the new value of the variable. This can be a constant, a variable, or a function call expression. In `.emacs', constants are used most of the time. They can be: Numbers: Integers are written in decimal, with an optional initial minus sign. If a sequence of digits is followed by a period and another sequence of digits, it is interpreted as a floating point number. Strings: Lisp string syntax is the same as C string syntax with a few extra features. Use a double-quote character to begin and end a string constant. Newlines and special characters may be present literally in strings. They can also be represented as backslash sequences: `\n' for newline, `\b' for backspace, `\r' for return, `\t' for tab, `\f' for formfeed (control-l), `\e' for escape, `\\' for a backslash, `\"' for a double-quote, or `\OOO' for the character whose octal code is OOO. Backslash and double-quote are the only characters for which backslash sequences are mandatory. You can use `\C-' as a prefix for a control character, as in `\C-s' for ASCII Control-S, and `\M-' as a prefix for a meta character, as in `\M-a' for Meta-A or `\M-\C-a' for Control-Meta-A. Characters: Lisp character constant syntax consists of a `?' followed by either a character or an escape sequence starting with `\'. Examples: `?x', `?\n', `?\"', `?\)'. Note that strings and characters are not interchangeable in Lisp; some contexts require one and some contexts require the other. True: `t' stands for `true'. False: `nil' stands for `false'. Other Lisp objects: Write a single-quote (') followed by the Lisp object you want. File: emacs, Node: Init Examples, Next: Terminal Init, Prev: Init Syntax, Up: Init File Init File Examples ------------------ Here are some examples of doing certain commonly desired things with Lisp expressions: * Make TAB in C mode just insert a tab if point is in the middle of a line. (setq c-tab-always-indent nil) Here we have a variable whose value is normally `t' for `true' and the alternative is `nil' for `false'. * Make searches case sensitive by default (in all buffers that do not override this). (setq-default case-fold-search nil) This sets the default value, which is effective in all buffers that do not have local values for the variable. Setting `case-fold-search' with `setq' affects only the current buffer's local value, which is probably not what you want to do in an init file. * Make Text mode the default mode for new buffers. (setq default-major-mode 'text-mode) Note that `text-mode' is used because it is the command for entering the mode we want. A single-quote is written before it to make a symbol constant; otherwise, `text-mode' would be treated as a variable name. * Turn on Auto Fill mode automatically in Text mode and related modes. (setq text-mode-hook '(lambda () (auto-fill-mode 1))) Here we have a variable whose value should be a Lisp function. The function we supply is a list starting with `lambda', and a single quote is written in front of it to make it (for the purpose of this `setq') a list constant rather than an expression. Lisp functions are not explained here; for mode hooks it is enough to know that `(auto-fill-mode 1)' is an expression that will be executed when Text mode is entered. You could replace it with any other expression that you like, or with several expressions in a row. (setq text-mode-hook 'turn-on-auto-fill) This is another way to accomplish the same result. `turn-on-auto-fill' is a symbol whose function definition is `(lambda () (auto-fill-mode 1))'. * Load the installed Lisp library named `foo' (actually a file `foo.elc' or `foo.el' in a standard Emacs directory). (load "foo") When the argument to `load' is a relative pathname, not starting with `/' or `~', `load' searches the directories in `load-path' (*note Loading::.). * Load the compiled Lisp file `foo.elc' from your home directory. (load "~/foo.elc") Here an absolute file name is used, so no searching is done. * Rebind the key `C-x l' to run the function `make-symbolic-link'. (global-set-key "\C-xl" 'make-symbolic-link) or (define-key global-map "\C-xl" 'make-symbolic-link) Note once again the single-quote used to refer to the symbol `make-symbolic-link' instead of its value as a variable. * Do the same thing for C mode only. (define-key c-mode-map "\C-xl" 'make-symbolic-link) * Bind the function key F1 to a command in C mode. Note that the names of function keys must be lower case. (define-key c-mode-map 'f1 'make-symbolic-link) * Bind the shifted version of F1 to a command. (define-key c-mode-map '(shift f1) 'make-symbolic-link) * Redefine all keys which now run `next-line' in Fundamental mode to run `forward-line' instead. (substitute-key-definition 'next-line 'forward-line global-map) * Make `C-x C-v' undefined. (global-unset-key "\C-x\C-v") One reason to undefine a key is so that you can make it a prefix. Simply defining `C-x C-v ANYTHING' would make `C-x C-v' a prefix, but `C-x C-v' must be freed of any non-prefix definition first. * Make `$' have the syntax of punctuation in Text mode. Note the use of a character constant for `$'. (modify-syntax-entry ?\$ "." text-mode-syntax-table) * Enable the use of the command `eval-expression' without confirmation. (put 'eval-expression 'disabled nil) File: emacs, Node: Terminal Init, Prev: Init Examples, Up: Init File Terminal-specific Initialization -------------------------------- Each terminal type can have a Lisp library to be loaded into Emacs when it is run on that type of terminal. For a terminal type named TERMTYPE, the library is called `term/TERMTYPE' and it is found by searching the directories `load-path' as usual and trying the suffixes `.elc' and `.el'. Normally it appears in the subdirectory `term' of the directory where most Emacs libraries are kept. The usual purpose of the terminal-specific library is to define the escape sequences used by the terminal's function keys using the library `keypad.el'. See the file `term/vt100.el' for an example of how this is done. When the terminal type contains a hyphen, only the part of the name before the first hyphen is significant in choosing the library name. Thus, terminal types `aaa-48' and `aaa-30-rv' both use the library `term/aaa'. The code in the library can use `(getenv "TERM")' to find the full terminal type name. The library's name is constructed by concatenating the value of the variable `term-file-prefix' and the terminal type. Your `.emacs' file can prevent the loading of the terminal-specific library by setting `term-file-prefix' to `nil'. The value of the variable `term-setup-hook', if not `nil', is called as a function of no arguments at the end of Emacs initialization, after both your `.emacs' file and any terminal-specific library have been read. You can set the value in the `.emacs' file to override part of any of the terminal-specific libraries and to define initializations for terminals that do not have a library. File: emacs, Node: Audible Bell, Next: Faces, Prev: Init File, Up: Customization Changing the Bell Sound ======================= You can now change how the audible bell sounds using the variable `sound-alist'. `sound-alist''s value is an alist associating symbols with strings of audio-data. When `ding' is called with one of the symbols, the associated sound data is played instead of the standard beep. This only works if you are logged in on the console of a SPARCstation. To listen to a sound of the provided type, call the function `play-sound' with the argument SOUND. You can also set the volume of the sound with the optional arugment VOLUME. Elements of the list should be of one of the following forms: ( symbol . string-or-symbol ) ( symbol integer string-or-symbol ) If `string-or-symbol' is a string, it should contain raw sound data, the contents of a `.au' file. If it is a symbol, the symbol is considered an alias for some other element, and the sound-player looks for that next. If the integer is provided, it is the volume at which the sound should be played, from 0 to 100. If an element of this alist begins with the symbol `default', that sound is used when no other sound is appropriate. If the symbol `t' is in place of a sound-string, Emacs uses the default X beep. This allows you to define beep-types of different volumes even when not running on the console of a SPARCstation. You can add things to this list by calling the function `load-sound-file', which reads in an audio-file and adds its data to the sound-alist. You can specify the sound with the SOUND-NAME argument and the file into which the sounds are loaded with the FILENAME argument. The optional VOLUME argument sets the volume. `load-sound-file (filename sound-name &optional volume)' To load and install some sound files as beep-types, use the function `load-default-sounds' (note that this only works if you are on display 0 of a SPARCstation). The following beep-types are used by Emacs itself. Other Lisp packages may use other beep types, but these are the ones that the C kernel of Emacs uses. `auto-save-error' An auto-save does not succeed `command-error' The Emacs command loop catches an error `undefined-key' You type a key that is undefined `undefined-click' You use an undefined mouse-click combination `no-completion' Completion was not possible `y-or-n-p' You type something other than the required `y' or `n' `yes-or-no-p' When you type something other than `yes' or `no' File: emacs, Node: Faces, Prev: Audible Bell, Up: Customization Faces ===== Lucid GNU Emacs has objects called extents and faces. An "extent" is a region of text and a "face" is a collection of textual attributes, such as fonts and colors. Every extent is displayed in some face, therefore, changing the properties of a face immediately updates the display of all associated extents. Faces can be screen-local: you can have a region of text that displays with completely different attributes when its buffer is viewed from a different X window. The display attributes of faces may be specified either in Lisp or through the X resource manager. Customizing Faces ----------------- You can change the face of an extent with the functions in this section. All the functions prompt for a FACE as an argument; use completion for a list of possible values. `M-x invert-face' Swap the foreground and background colors of the given FACE. `M-x make-face-bold' Make the font of the given FACE bold. When called from a program, returns `nil' if this is not possible. `M-x make-face-bold-italic' Make the font of the given FACE bold italic. When called from a program, returns `nil' if not possible. `M-x make-face-italic' Make the font of the given FACE italic. When called from a program, returns `nil' if not possible. `M-x make-face-unbold' Make the font of the given FACE non-bold. When called from a program, returns `nil' if not possible. `M-x make-face-unitalic' Make the font of the given FACE non-italic. When called from a program, returns `nil' if not possible. `M-x set-face-background' Change the background color of the given FACE. `M-x set-face-background-pixmap' Change the background pixmap of the given FACE. `M-x set-face-font' Change the font of the given FACE. `M-x set-face-foreground' Change the foreground color of the given FACE. `M-x set-face-underline-p' Change whether the given FACE is underlined. You can exchange the foreground and background color of the selected FACE with the function `invert-face'. If the face does not specify both foreground and background, then its foreground and background are set to the background and foreground of the default face. When calling this from a program, you can supply the optional argument SCREEN to specify which screen is affected; otherwise, all screens are affected. You can set the background color of the specified FACE with the function `set-face-background'. The argument `color' should be a string, the name of a color. When called from a program, if the optional SCREEN argument is provided, the face is changed only in that screen; otherwise, it is changed in all screens. You can set the background pixmap of the specified FACE with the function `set-face-background-pixmap'. The pixmap argument NAME should be a string, the name of a file of pixmap data. The directories listed in the `x-bitmap-file-path' variable are searched. The bitmap may also be a list of the form `(width height data)' where width and height are the size in pixels, and data is a string containing the raw bits of the bitmap. If the optional SCREEN argument is provided, the face is changed only in that screen; otherwise, it is changed in all screens. The variable `x-bitmap-file-path' takes as a value a list of the directories in which X bitmap files may be found. If the value is `nil', the list is initialized from the `*bitmapFilePath' resource. You can set the font of the specified FACE with the function `set-face-font'. The FONT argument should be a string, the name of a font. When called from a program, if the optional SCREEN argument is provided, the face is changed only in that screen; otherwise, it is changed in all screens. You can set the foreground color of the specified FACE with the function `set-face-foreground'. The argument COLOR should be a string, the name of a color. If the optional SCREEN argument is provided, the face is changed only in that screen; otherwise, it is changed in all screens. You can set underline the specified FACE with the function `set-face-underline-p'. The argument UNDERLINE-P can be used to make underlining an attribute of the face or not. If the optional SCREEN argument is provided, the face is changed only in that screen; otherwise, it is changed in all screens.