update.

[chise/xemacs-chise.git-] / info / xemacs.info-9

This is ../info/xemacs.info, produced by makeinfo version 4.0 from
xemacs/xemacs.texi.

INFO-DIR-SECTION XEmacs Editor
START-INFO-DIR-ENTRY
* XEmacs: (xemacs).             XEmacs Editor.
END-INFO-DIR-ENTRY

   This file documents the XEmacs editor.

   Copyright (C) 1985, 1986, 1988 Richard M. Stallman.  Copyright (C)
1991, 1992, 1993, 1994 Lucid, Inc.  Copyright (C) 1993, 1994 Sun
Microsystems, Inc.  Copyright (C) 1995 Amdahl Corporation.

   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.

\1f
File: xemacs.info,  Node: Change Window,  Prev: Pop Up Window,  Up: Windows

Deleting and Rearranging Windows
================================

`C-x 0'
     Get rid of the selected window (`delete-window').  That is a zero.
     If there is more than one Emacs frame, deleting the sole remaining
     window on that frame deletes the frame as well. If the current
     frame is the only frame, it is not deleted.

`C-x 1'
     Get rid of all windows except the selected one
     (`delete-other-windows').

`C-x ^'
     Make the selected window taller, at the expense of the other(s)
     (`enlarge-window').

`C-x }'
     Make the selected window wider (`enlarge-window-horizontally').

   To delete a window, type `C-x 0' (`delete-window').  (That is a
zero.)  The space occupied by the deleted window is distributed among
the other active windows (but not the minibuffer window, even if that
is active at the time).  Once a window is deleted, its attributes are
forgotten; there is no automatic way to make another window of the same
shape or showing the same buffer.  The buffer continues to exist, and
you can select it in any window with `C-x b'.

   `C-x 1' (`delete-other-windows') is more powerful than `C-x 0'; it
deletes all the windows except the selected one (and the minibuffer).
The selected window expands to use the whole frame except for the echo
area.

   To readjust the division of space among existing windows, use `C-x
^' (`enlarge-window').  It makes the currently selected window longer
by one line or as many lines as a numeric argument specifies.  With a
negative argument, it makes the selected window smaller.  `C-x }'
(`enlarge-window-horizontally') makes the selected window wider by the
specified number of columns.  The extra screen space given to a window
comes from one of its neighbors, if that is possible; otherwise, all
the competing windows are shrunk in the same proportion.  If this makes
some windows too small, those windows are deleted and their space is
divided up.   Minimum window size is specified by the variables
`window-min-height' and `window-min-width'.

   You can also resize windows within a frame by clicking the left mouse
button on a modeline, and dragging.

   Clicking the right button on a mode line pops up a menu of common
window manager operations.  This menu contains the following options:

Delete Window
     Remove the window above this modeline from the frame.

Delete Other Windows
     Delete all windows on the frame except for the one above this
     modeline.

Split Window
     Split the window above the mode line in half, creating another
     window.

Split Window Horizontally
     Split the window above the mode line in half horizontally, so that
     there will be two windows side-by-side.

Balance Windows
     Readjust the sizes of all windows on the frame until all windows
     have roughly the same number of lines.

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File: xemacs.info,  Node: Mule,  Next: Major Modes,  Prev: Windows,  Up: Top

World Scripts Support
*********************

   If you compile XEmacs with mule option, it supports a wide variety of
world scripts, including Latin script, as well as Arabic script,
Simplified Chinese script (for mainland of China), Traditional Chinese
script (for Taiwan and Hong-Kong), Greek script, Hebrew script, IPA
symbols, Japanese scripts (Hiragana, Katakana and Kanji), Korean scripts
(Hangul and Hanja) and Cyrillic script (for Beylorussian, Bulgarian,
Russian, Serbian and Ukrainian).  These features have been merged from
the modified version of Emacs known as MULE (for "MULti-lingual
Enhancement to GNU Emacs").

* Menu:

* Mule Intro::              Basic concepts of Mule.
* Language Environments::   Setting things up for the language you use.
* Input Methods::           Entering text characters not on your keyboard.
* Select Input Method::     Specifying your choice of input methods.
* Coding Systems::          Character set conversion when you read and
                              write files, and so on.
* Recognize Coding::        How XEmacs figures out which conversion to use.
* Specify Coding::          Various ways to choose which conversion to use.

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File: xemacs.info,  Node: Mule Intro,  Next: Language Environments,  Prev: Mule,  Up: Mule

Introduction to world scripts
=============================

   The users of these scripts have established many more-or-less
standard coding systems for storing files.  XEmacs translates between
the internal character encoding and various other coding systems when
reading and writing files, when exchanging data with subprocesses, and
(in some cases) in the `C-q' command (see below).

   The command `C-h h' (`view-hello-file') displays the file
`etc/HELLO', which shows how to say "hello" in many languages.  This
illustrates various scripts.

   Keyboards, even in the countries where these character sets are used,
generally don't have keys for all the characters in them.  So XEmacs
supports various "input methods", typically one for each script or
language, to make it convenient to type them.

   The prefix key `C-x <RET>' is used for commands that pertain to
world scripts, coding systems, and input methods.

\1f
File: xemacs.info,  Node: Language Environments,  Next: Input Methods,  Prev: Mule Intro,  Up: Mule

Language Environments
=====================

   All supported character sets are supported in XEmacs buffers if it is
compile with mule; there is no need to select a particular language in
order to display its characters in an XEmacs buffer.  However, it is
important to select a "language environment" in order to set various
defaults.  The language environment really represents a choice of
preferred script (more or less) rather that a choice of language.

   The language environment controls which coding systems to recognize
when reading text (*note Recognize Coding::).  This applies to files,
incoming mail, netnews, and any other text you read into XEmacs.  It may
also specify the default coding system to use when you create a file.
Each language environment also specifies a default input method.

   The command to select a language environment is `M-x
set-language-environment'.  It makes no difference which buffer is
current when you use this command, because the effects apply globally to
the XEmacs session.  The supported language environments include:

     Chinese-BIG5, Chinese-CNS, Chinese-GB, Cyrillic-ISO, English,
     Ethiopic, Greek, Japanese, Korean, Latin-1, Latin-2, Latin-3,
     Latin-4, Latin-5.

   Some operating systems let you specify the language you are using by
setting locale environment variables.  XEmacs handles one common special
case of this: if your locale name for character types contains the
string `8859-N', XEmacs automatically selects the corresponding
language environment.

   To display information about the effects of a certain language
environment LANG-ENV, use the command `C-h L LANG-ENV <RET>'
(`describe-language-environment').  This tells you which languages this
language environment is useful for, and lists the character sets,
coding systems, and input methods that go with it.  It also shows some
sample text to illustrate scripts used in this language environment.
By default, this command describes the chosen language environment.

\1f
File: xemacs.info,  Node: Input Methods,  Next: Select Input Method,  Prev: Language Environments,  Up: Mule

Input Methods
=============

   An "input method" is a kind of character conversion designed
specifically for interactive input.  In XEmacs, typically each language
has its own input method; sometimes several languages which use the same
characters can share one input method.  A few languages support several
input methods.

   The simplest kind of input method works by mapping ASCII letters into
another alphabet.  This is how the Greek and Russian input methods work.

   A more powerful technique is composition: converting sequences of
characters into one letter.  Many European input methods use composition
to produce a single non-ASCII letter from a sequence that consists of a
letter followed by accent characters.  For example, some methods convert
the sequence `'a' into a single accented letter.

   The input methods for syllabic scripts typically use mapping followed
by composition.  The input methods for Thai and Korean work this way.
First, letters are mapped into symbols for particular sounds or tone
marks; then, sequences of these which make up a whole syllable are
mapped into one syllable sign.

   Chinese and Japanese require more complex methods.  In Chinese input
methods, first you enter the phonetic spelling of a Chinese word (in
input method `chinese-py', among others), or a sequence of portions of
the character (input methods `chinese-4corner' and `chinese-sw', and
others).  Since one phonetic spelling typically corresponds to many
different Chinese characters, you must select one of the alternatives
using special XEmacs commands.  Keys such as `C-f', `C-b', `C-n',
`C-p', and digits have special definitions in this situation, used for
selecting among the alternatives.  <TAB> displays a buffer showing all
the possibilities.

   In Japanese input methods, first you input a whole word using
phonetic spelling; then, after the word is in the buffer, XEmacs
converts it into one or more characters using a large dictionary.  One
phonetic spelling corresponds to many differently written Japanese
words, so you must select one of them; use `C-n' and `C-p' to cycle
through the alternatives.

   Sometimes it is useful to cut off input method processing so that the
characters you have just entered will not combine with subsequent
characters.  For example, in input method `latin-1-postfix', the
sequence `e '' combines to form an `e' with an accent.  What if you
want to enter them as separate characters?

   One way is to type the accent twice; that is a special feature for
entering the separate letter and accent.  For example, `e ' '' gives
you the two characters `e''.  Another way is to type another letter
after the `e'--something that won't combine with that--and immediately
delete it.  For example, you could type `e e <DEL> '' to get separate
`e' and `''.

   Another method, more general but not quite as easy to type, is to use
`C-\ C-\' between two characters to stop them from combining.  This is
the command `C-\' (`toggle-input-method') used twice.  *Note Select
Input Method::.

   `C-\ C-\' is especially useful inside an incremental search, because
stops waiting for more characters to combine, and starts searching for
what you have already entered.

   The variables `input-method-highlight-flag' and
`input-method-verbose-flag' control how input methods explain what is
happening.  If `input-method-highlight-flag' is non-`nil', the partial
sequence is highlighted in the buffer.  If `input-method-verbose-flag'
is non-`nil', the list of possible characters to type next is displayed
in the echo area (but not when you are in the minibuffer).

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File: xemacs.info,  Node: Select Input Method,  Next: Coding Systems,  Prev: Input Methods,  Up: Mule

Selecting an Input Method
=========================

`C-\'
     Enable or disable use of the selected input method.

`C-x <RET> C-\ METHOD <RET>'
     Select a new input method for the current buffer.

`C-h I METHOD <RET>'
`C-h C-\ METHOD <RET>'
     Describe the input method METHOD (`describe-input-method').  By
     default, it describes the current input method (if any).

`M-x list-input-methods'
     Display a list of all the supported input methods.

   To choose an input method for the current buffer, use `C-x <RET>
C-\' (`select-input-method').  This command reads the input method name
with the minibuffer; the name normally starts with the language
environment that it is meant to be used with.  The variable
`current-input-method' records which input method is selected.

   Input methods use various sequences of ASCII characters to stand for
non-ASCII characters.  Sometimes it is useful to turn off the input
method temporarily.  To do this, type `C-\' (`toggle-input-method').
To reenable the input method, type `C-\' again.

   If you type `C-\' and you have not yet selected an input method, it
prompts for you to specify one.  This has the same effect as using `C-x
<RET> C-\' to specify an input method.

   Selecting a language environment specifies a default input method for
use in various buffers.  When you have a default input method, you can
select it in the current buffer by typing `C-\'.  The variable
`default-input-method' specifies the default input method (`nil' means
there is none).

   Some input methods for alphabetic scripts work by (in effect)
remapping the keyboard to emulate various keyboard layouts commonly used
for those scripts.  How to do this remapping properly depends on your
actual keyboard layout.  To specify which layout your keyboard has, use
the command `M-x quail-set-keyboard-layout'.

   To display a list of all the supported input methods, type `M-x
list-input-methods'.  The list gives information about each input
method, including the string that stands for it in the mode line.

\1f
File: xemacs.info,  Node: Coding Systems,  Next: Recognize Coding,  Prev: Select Input Method,  Up: Mule

Coding Systems
==============

   Users of various languages have established many more-or-less
standard coding systems for representing them.  XEmacs does not use
these coding systems internally; instead, it converts from various
coding systems to its own system when reading data, and converts the
internal coding system to other coding systems when writing data.
Conversion is possible in reading or writing files, in sending or
receiving from the terminal, and in exchanging data with subprocesses.

   XEmacs assigns a name to each coding system.  Most coding systems are
used for one language, and the name of the coding system starts with the
language name.  Some coding systems are used for several languages;
their names usually start with `iso'.  There are also special coding
systems `binary' and `no-conversion' which do not convert printing
characters at all.

   In addition to converting various representations of non-ASCII
characters, a coding system can perform end-of-line conversion.  XEmacs
handles three different conventions for how to separate lines in a file:
newline, carriage-return linefeed, and just carriage-return.

`C-h C CODING <RET>'
     Describe coding system CODING.

`C-h C <RET>'
     Describe the coding systems currently in use.

`M-x list-coding-systems'
     Display a list of all the supported coding systems.

   The command `C-h C' (`describe-coding-system') displays information
about particular coding systems.  You can specify a coding system name
as argument; alternatively, with an empty argument, it describes the
coding systems currently selected for various purposes, both in the
current buffer and as the defaults, and the priority list for
recognizing coding systems (*note Recognize Coding::).

   To display a list of all the supported coding systems, type `M-x
list-coding-systems'.  The list gives information about each coding
system, including the letter that stands for it in the mode line (*note
Mode Line::).

   Each of the coding systems that appear in this list--except for
`binary', which means no conversion of any kind--specifies how and
whether to convert printing characters, but leaves the choice of
end-of-line conversion to be decided based on the contents of each file.
For example, if the file appears to use carriage-return linefeed between
lines, that end-of-line conversion will be used.

   Each of the listed coding systems has three variants which specify
exactly what to do for end-of-line conversion:

`...-unix'
     Don't do any end-of-line conversion; assume the file uses newline
     to separate lines.  (This is the convention normally used on Unix
     and GNU systems.)

`...-dos'
     Assume the file uses carriage-return linefeed to separate lines,
     and do the appropriate conversion.  (This is the convention
     normally used on Microsoft systems.)

`...-mac'
     Assume the file uses carriage-return to separate lines, and do the
     appropriate conversion.  (This is the convention normally used on
     the Macintosh system.)

   These variant coding systems are omitted from the
`list-coding-systems' display for brevity, since they are entirely
predictable.  For example, the coding system `iso-8859-1' has variants
`iso-8859-1-unix', `iso-8859-1-dos' and `iso-8859-1-mac'.

   In contrast, the coding system `binary' specifies no character code
conversion at all--none for non-Latin-1 byte values and none for end of
line.  This is useful for reading or writing binary files, tar files,
and other files that must be examined verbatim.

   The easiest way to edit a file with no conversion of any kind is with
the `M-x find-file-literally' command.  This uses `binary', and also
suppresses other XEmacs features that might convert the file contents
before you see them.  *Note Visiting::.

   The coding system `no-conversion' means that the file contains
non-Latin-1 characters stored with the internal XEmacs encoding.  It
handles end-of-line conversion based on the data encountered, and has
the usual three variants to specify the kind of end-of-line conversion.

\1f
File: xemacs.info,  Node: Recognize Coding,  Next: Specify Coding,  Prev: Coding Systems,  Up: Mule

Recognizing Coding Systems
==========================

   Most of the time, XEmacs can recognize which coding system to use for
any given file-once you have specified your preferences.

   Some coding systems can be recognized or distinguished by which byte
sequences appear in the data.  However, there are coding systems that
cannot be distinguished, not even potentially.  For example, there is no
way to distinguish between Latin-1 and Latin-2; they use the same byte
values with different meanings.

   XEmacs handles this situation by means of a priority list of coding
systems.  Whenever XEmacs reads a file, if you do not specify the coding
system to use, XEmacs checks the data against each coding system,
starting with the first in priority and working down the list, until it
finds a coding system that fits the data.  Then it converts the file
contents assuming that they are represented in this coding system.

   The priority list of coding systems depends on the selected language
environment (*note Language Environments::).  For example, if you use
French, you probably want XEmacs to prefer Latin-1 to Latin-2; if you
use Czech, you probably want Latin-2 to be preferred.  This is one of
the reasons to specify a language environment.

   However, you can alter the priority list in detail with the command
`M-x prefer-coding-system'.  This command reads the name of a coding
system from the minibuffer, and adds it to the front of the priority
list, so that it is preferred to all others.  If you use this command
several times, each use adds one element to the front of the priority
list.

   Sometimes a file name indicates which coding system to use for the
file.  The variable `file-coding-system-alist' specifies this
correspondence.  There is a special function
`modify-coding-system-alist' for adding elements to this list.  For
example, to read and write all `.txt' using the coding system
`china-iso-8bit', you can execute this Lisp expression:

     (modify-coding-system-alist 'file "\\.txt\\'" 'china-iso-8bit)

The first argument should be `file', the second argument should be a
regular expression that determines which files this applies to, and the
third argument says which coding system to use for these files.

   You can specify the coding system for a particular file using the
`-*-...-*-' construct at the beginning of a file, or a local variables
list at the end (*note File Variables::).  You do this by defining a
value for the "variable" named `coding'.  XEmacs does not really have a
variable `coding'; instead of setting a variable, it uses the specified
coding system for the file.  For example, `-*-mode: C; coding:
iso-8859-1;-*-' specifies use of the iso-8859-1 coding system, as well
as C mode.

   Once XEmacs has chosen a coding system for a buffer, it stores that
coding system in `buffer-file-coding-system' and uses that coding
system, by default, for operations that write from this buffer into a
file.  This includes the commands `save-buffer' and `write-region'.  If
you want to write files from this buffer using a different coding
system, you can specify a different coding system for the buffer using
`set-buffer-file-coding-system' (*note Specify Coding::).

\1f
File: xemacs.info,  Node: Specify Coding,  Prev: Recognize Coding,  Up: Mule

Specifying a Coding System
==========================

   In cases where XEmacs does not automatically choose the right coding
system, you can use these commands to specify one:

`C-x <RET> f CODING <RET>'
     Use coding system CODING for the visited file in the current
     buffer.

`C-x <RET> c CODING <RET>'
     Specify coding system CODING for the immediately following command.

`C-x <RET> k CODING <RET>'
     Use coding system CODING for keyboard input.

`C-x <RET> t CODING <RET>'
     Use coding system CODING for terminal output.

`C-x <RET> p CODING <RET>'
     Use coding system CODING for subprocess input and output in the
     current buffer.

   The command `C-x RET f' (`set-buffer-file-coding-system') specifies
the file coding system for the current buffer--in other words, which
coding system to use when saving or rereading the visited file.  You
specify which coding system using the minibuffer.  Since this command
applies to a file you have already visited, it affects only the way the
file is saved.

   Another way to specify the coding system for a file is when you visit
the file.  First use the command `C-x <RET> c'
(`universal-coding-system-argument'); this command uses the minibuffer
to read a coding system name.  After you exit the minibuffer, the
specified coding system is used for _the immediately following command_.

   So if the immediately following command is `C-x C-f', for example,
it reads the file using that coding system (and records the coding
system for when the file is saved).  Or if the immediately following
command is `C-x C-w', it writes the file using that coding system.
Other file commands affected by a specified coding system include `C-x
C-i' and `C-x C-v', as well as the other-window variants of `C-x C-f'.

   In addition, if you run some file input commands with the precedent
`C-u', you can specify coding system to read from minibuffer.  So if
the immediately following command is `C-x C-f', for example, it reads
the file using that coding system (and records the coding system for
when the file is saved).  Other file commands affected by a specified
coding system include `C-x C-i' and `C-x C-v', as well as the
other-window variants of `C-x C-f'.

   The variable `default-buffer-file-coding-system' specifies the
choice of coding system to use when you create a new file.  It applies
when you find a new file, and when you create a buffer and then save it
in a file.  Selecting a language environment typically sets this
variable to a good choice of default coding system for that language
environment.

   The command `C-x <RET> t' (`set-terminal-coding-system') specifies
the coding system for terminal output.  If you specify a character code
for terminal output, all characters output to the terminal are
translated into that coding system.

   This feature is useful for certain character-only terminals built to
support specific languages or character sets--for example, European
terminals that support one of the ISO Latin character sets.

   By default, output to the terminal is not translated at all.

   The command `C-x <RET> k' (`set-keyboard-coding-system') specifies
the coding system for keyboard input.  Character-code translation of
keyboard input is useful for terminals with keys that send non-ASCII
graphic characters--for example, some terminals designed for ISO
Latin-1 or subsets of it.

   By default, keyboard input is not translated at all.

   There is a similarity between using a coding system translation for
keyboard input, and using an input method: both define sequences of
keyboard input that translate into single characters.  However, input
methods are designed to be convenient for interactive use by humans, and
the sequences that are translated are typically sequences of ASCII
printing characters.  Coding systems typically translate sequences of
non-graphic characters.

   The command `C-x <RET> p' (`set-buffer-process-coding-system')
specifies the coding system for input and output to a subprocess.  This
command applies to the current buffer; normally, each subprocess has its
own buffer, and thus you can use this command to specify translation to
and from a particular subprocess by giving the command in the
corresponding buffer.

   By default, process input and output are not translated at all.

   The variable `file-name-coding-system' specifies a coding system to
use for encoding file names.  If you set the variable to a coding
system name (as a Lisp symbol or a string), XEmacs encodes file names
using that coding system for all file operations.  This makes it
possible to use non-Latin-1 characters in file names--or, at least,
those non-Latin-1 characters which the specified coding system can
encode.  By default, this variable is `nil', which implies that you
cannot use non-Latin-1 characters in file names.

\1f
File: xemacs.info,  Node: Major Modes,  Next: Indentation,  Prev: Mule,  Up: Top

Major Modes
***********

   Emacs has many different "major modes", each of which customizes
Emacs for editing text of a particular sort.  The major modes are
mutually exclusive;  at any time, each buffer has one major mode.  The
mode line normally contains the name of the current major mode in
parentheses.  *Note Mode Line::.

   The least specialized major mode is called "Fundamental mode".  This
mode has no mode-specific redefinitions or variable settings.  Each
Emacs command behaves in its most general manner, and each option is in
its default state.  For editing any specific type of text, such as Lisp
code or English text, you should switch to the appropriate major mode,
such as Lisp mode or Text mode.

   Selecting a major mode changes the meanings of a few keys to become
more specifically adapted to the language being edited.  <TAB>, <DEL>,
and <LFD> are changed frequently.  In addition, commands which handle
comments use the mode to determine how to delimit comments.  Many major
modes redefine the syntactical properties of characters appearing in
the buffer.  *Note Syntax::.

   The major modes fall into three major groups.  Lisp mode (which has
several variants), C mode, and Muddle mode are for specific programming
languages.  Text mode, Nroff mode, TeX mode, and Outline mode are for
editing English text.  The remaining major modes are not intended for
use on users' files; they are used in buffers created by Emacs for
specific purposes and include Dired mode for buffers made by Dired
(*note Dired::), Mail mode for buffers made by `C-x m' (*note Sending
Mail::), and Shell mode for buffers used for communicating with an
inferior shell process (*note Interactive Shell::).

   Most programming language major modes specify that only blank lines
separate paragraphs.  This is so that the paragraph commands remain
useful.  *Note Paragraphs::.  They also cause Auto Fill mode to use the
definition of <TAB> to indent the new lines it creates.  This is
because most lines in a program are usually indented.  *Note
Indentation::.

* Menu:

* Choosing Modes::     How major modes are specified or chosen.

\1f
File: xemacs.info,  Node: Choosing Modes,  Prev: Major Modes,  Up: Major Modes

Choosing Major Modes
====================

   You can select a major mode explicitly for the current buffer, but
most of the time Emacs determines which mode to use based on the file
name or some text in the file.

   Use a `M-x' command to explicitly select a new major mode.  Add
`-mode' to the name of a major mode to get the name of a command to
select that mode.  For example, to enter Lisp mode, execute `M-x
lisp-mode'.

   When you visit a file, Emacs usually chooses the right major mode
based on the file's name.  For example, files whose names end in `.c'
are edited in C mode.  The variable `auto-mode-alist' controls the
correspondence between file names and major mode.  Its value is a list
in which each element has the form:

     (REGEXP . MODE-FUNCTION)

For example, one element normally found in the list has the form
`("\\.c$" . c-mode)'. It is responsible for selecting C mode for files
whose names end in `.c'.  (Note that `\\' is needed in Lisp syntax to
include a `\' in the string, which is needed to suppress the special
meaning of `.' in regexps.)  The only practical way to change this
variable is with Lisp code.

   You can specify which major mode should be used for editing a certain
file by a special sort of text in the first non-blank line of the file.
The mode name should appear in this line both preceded and followed by
`-*-'.  Other text may appear on the line as well.  For example,

     ;-*-Lisp-*-

tells Emacs to use Lisp mode.  Note how the semicolon is used to make
Lisp treat this line as a comment.  Such an explicit specification
overrides any default mode based on the file name.

   Another format of mode specification is:

     -*-Mode: MODENAME;-*-

which allows other things besides the major mode name to be specified.
However, Emacs does not look for anything except the mode name.

   The major mode can also be specified in a local variables list.
*Note File Variables::.

   When you visit a file that does not specify a major mode to use, or
when you create a new buffer with `C-x b', Emacs uses the major mode
specified by the variable `default-major-mode'.  Normally this value is
the symbol `fundamental-mode', which specifies Fundamental mode.  If
`default-major-mode' is `nil', the major mode is taken from the
previously selected buffer.

\1f
File: xemacs.info,  Node: Indentation,  Next: Text,  Prev: Major Modes,  Up: Top

Indentation
***********

`<TAB>'
     Indent current line "appropriately" in a mode-dependent fashion.

`<LFD>'
     Perform <RET> followed by <TAB> (`newline-and-indent').

`M-^'
     Merge two lines (`delete-indentation').  This would cancel out the
     effect of <LFD>.

`C-M-o'
     Split line at point; text on the line after point becomes a new
     line indented to the same column that it now starts in
     (`split-line').

`M-m'
     Move (forward or back) to the first non-blank character on the
     current line (`back-to-indentation').

`C-M-\'
     Indent several lines to same column (`indent-region').

`C-x <TAB>'
     Shift block of lines rigidly right or left (`indent-rigidly').

`M-i'
     Indent from point to the next prespecified tab stop column
     (`tab-to-tab-stop').

`M-x indent-relative'
     Indent from point to under an indentation point in the previous
     line.

   Most programming languages have some indentation convention.  For
Lisp code, lines are indented according to their nesting in
parentheses.  The same general idea is used for C code, though details
differ.

   Use the <TAB> command to indent a line whatever the language.  Each
major mode defines this command to perform indentation appropriate for
the particular language.  In Lisp mode, <TAB> aligns a line according
to its depth in parentheses.  No matter where in the line you are when
you type <TAB>, it aligns the line as a whole.  In C mode, <TAB>
implements a subtle and sophisticated indentation style that knows
about many aspects of C syntax.

   In Text mode, <TAB> runs the command `tab-to-tab-stop', which
indents to the next tab stop column.  You can set the tab stops with
`M-x edit-tab-stops'.

* Menu:

* Indentation Commands:: Various commands and techniques for indentation.
* Tab Stops::            You can set arbitrary "tab stops" and then
                         indent to the next tab stop when you want to.
* Just Spaces::          You can request indentation using just spaces.

\1f
File: xemacs.info,  Node: Indentation Commands,  Next: Tab Stops,  Prev: Indentation,  Up: Indentation

Indentation Commands and Techniques
===================================

   If you just want to insert a tab character in the buffer, you can
type `C-q <TAB>'.

   To move over the indentation on a line, type `Meta-m'
(`back-to-indentation').  This command, given anywhere on a line,
positions point at the first non-blank character on the line.

   To insert an indented line before the current line, type `C-a C-o
<TAB>'.  To make an indented line after the current line, use `C-e
<LFD>'.

   `C-M-o' (`split-line') moves the text from point to the end of the
line vertically down, so that the current line becomes two lines.
`C-M-o' first moves point forward over any spaces and tabs.  Then it
inserts after point a newline and enough indentation to reach the same
column point is on.  Point remains before the inserted newline; in this
regard, `C-M-o' resembles `C-o'.

   To join two lines cleanly, use the `Meta-^' (`delete-indentation')
command to delete the indentation at the front of the current line, and
the line boundary as well.  Empty spaces are replaced by a single
space, or by no space if at the beginning of a line, before a close
parenthesis, or after an open parenthesis.  To delete just the
indentation of a line, go to the beginning of the line and use `Meta-\'
(`delete-horizontal-space'), which deletes all spaces and tabs around
the cursor.

   There are also commands for changing the indentation of several
lines at once.  `Control-Meta-\' (`indent-region') gives each line which
begins in the region the "usual" indentation by invoking <TAB> at the
beginning of the line.  A numeric argument specifies the column to
indent to.  Each line is shifted left or right so that its first
non-blank character appears in that column.  `C-x <TAB>'
(`indent-rigidly') moves all the lines in the region right by its
argument (left, for negative arguments).  The whole group of lines moves
rigidly sideways, which is how the command gets its name.

   `M-x indent-relative' indents at point based on the previous line
(actually, the last non-empty line.)  It inserts whitespace at point,
moving point, until it is underneath an indentation point in the
previous line.  An indentation point is the end of a sequence of
whitespace or the end of the line.  If point is farther right than any
indentation point in the previous line, the whitespace before point is
deleted and the first indentation point then applicable is used.  If no
indentation point is applicable even then, `tab-to-tab-stop' is run
(see next section).

   `indent-relative' is the definition of <TAB> in Indented Text mode.
*Note Text::.

\1f
File: xemacs.info,  Node: Tab Stops,  Next: Just Spaces,  Prev: Indentation Commands,  Up: Indentation

Tab Stops
=========

   For typing in tables, you can use Text mode's definition of <TAB>,
`tab-to-tab-stop'.  This command inserts indentation before point,
enough to reach the next tab stop column.  Even if you are not in Text
mode, this function is associated with `M-i' anyway.

   You can arbitrarily set the tab stops used by `M-i'.  They are
stored as a list of column-numbers in increasing order in the variable
`tab-stop-list'.

   The convenient way to set the tab stops is using `M-x
edit-tab-stops', which creates and selects a buffer containing a
description of the tab stop settings.  You can edit this buffer to
specify different tab stops, and then type `C-c C-c' to make those new
tab stops take effect.  In the tab stop buffer, `C-c C-c' runs the
function `edit-tab-stops-note-changes' rather than the default
`save-buffer'.  `edit-tab-stops' records which buffer was current when
you invoked it, and stores the tab stops in that buffer.  Normally all
buffers share the same tab stops and changing them in one buffer
affects all.  If you make `tab-stop-list' local in one buffer
`edit-tab-stops' in that buffer edits only the local settings.

   Below is the text representing ordinary tab stops every eight
columns:

             :       :       :       :       :       :
     0         1         2         3         4
     0123456789012345678901234567890123456789012345678
     To install changes, type C-c C-c

   The first line contains a colon at each tab stop.  The remaining
lines help you see where the colons are and tell you what to do.

   Note that the tab stops that control `tab-to-tab-stop' have nothing
to do with displaying tab characters in the buffer.  *Note Display
Vars::, for more information on that.

\1f
File: xemacs.info,  Node: Just Spaces,  Prev: Tab Stops,  Up: Indentation

Tabs vs. Spaces
===============

   Emacs normally uses both tabs and spaces to indent lines.  If you
prefer, all indentation can be made from spaces only.  To request this,
set `indent-tabs-mode' to `nil'.  This is a per-buffer variable;
altering the variable affects only the current buffer, but there is a
default value which you can change as well.  *Note Locals::.

   There are also commands to convert tabs to spaces or vice versa,
always preserving the columns of all non-blank text.  `M-x tabify'
scans the region for sequences of spaces, and converts sequences of at
least three spaces to tabs if that is possible without changing
indentation.  `M-x untabify' changes all tabs in the region to
corresponding numbers of spaces.

\1f
File: xemacs.info,  Node: Text,  Next: Programs,  Prev: Indentation,  Up: Top

Commands for Human Languages
****************************

   The term "text" has two widespread meanings in our area of the
computer field.  One is data that is a sequence of characters.  In this
sense of the word any file that you edit with Emacs is text.  The other
meaning is more restrictive: a sequence of characters in a human
language for humans to read (possibly after processing by a text
formatter), as opposed to a program or commands for a program.

   Human languages have syntactic and stylistic conventions that editor
commands should support or use to advantage: conventions involving
words, sentences, paragraphs, and capital letters.  This chapter
describes Emacs commands for all these things.  There are also commands
for "filling", or rearranging paragraphs into lines of approximately
equal length.  The commands for moving over and killing words,
sentences, and paragraphs, while intended primarily for editing text,
are also often useful for editing programs.

   Emacs has several major modes for editing human language text.  If a
file contains plain text, use Text mode, which customizes Emacs in
small ways for the syntactic conventions of text.  For text which
contains embedded commands for text formatters, Emacs has other major
modes, each for a particular text formatter.  Thus, for input to TeX,
you can use TeX mode; for input to nroff, Nroff mode.

* Menu:

* Text Mode::   The major modes for editing text files.
* Nroff Mode::  The major mode for editing input to the formatter nroff.
* TeX Mode::    The major modes for editing input to the formatter TeX.
* Outline Mode:: The major mode for editing outlines.
* Words::       Moving over and killing words.
* Sentences::   Moving over and killing sentences.
* Paragraphs::  Moving over paragraphs.
* Pages::       Moving over pages.
* Filling::     Filling or justifying text
* Case::        Changing the case of text

\1f
File: xemacs.info,  Node: Text Mode,  Next: Words,  Prev: Text,  Up: Text

Text Mode
=========

   You should use Text mode--rather than Fundamental or Lisp mode--to
edit files of text in a human language.  Invoke `M-x text-mode' to
enter Text mode.  In Text mode, <TAB> runs the function
`tab-to-tab-stop', which allows you to use arbitrary tab stops set with
`M-x edit-tab-stops' (*note Tab Stops::).  Features concerned with
comments in programs are turned off unless they are explicitly invoked.
The syntax table is changed so that periods are not considered part of a
word, while apostrophes, backspaces and underlines are.

   A similar variant mode is Indented Text mode, intended for editing
text in which most lines are indented.  This mode defines <TAB> to run
`indent-relative' (*note Indentation::), and makes Auto Fill indent the
lines it creates.  As a result, a line made by Auto Filling, or by
<LFD>, is normally indented just like the previous line.  Use `M-x
indented-text-mode' to select this mode.

   Entering Text mode or Indented Text mode calls the value of the
variable `text-mode-hook' with no arguments, if that value exists and
is not `nil'.  This value is also called when modes related to Text
mode are entered; this includes Nroff mode, TeX mode, Outline mode, and
Mail mode.  Your hook can look at the value of `major-mode' to see
which of these modes is actually being entered.

   Two modes similar to Text mode are of use for editing text that is to
be passed through a text formatter before achieving its final readable
form.

* Menu:

* Nroff Mode::  The major mode for editing input to the formatter nroff.
* TeX Mode::    The major modes for editing input to the formatter TeX.


  Another similar mode is used for editing outlines.  It allows you
to view the text at various levels of detail.  You can view either
the outline headings alone or both headings and text; you can also
hide some of the headings at lower levels from view to make the high
level structure more visible.


* Outline Mode:: The major mode for editing outlines.

\1f
File: xemacs.info,  Node: Nroff Mode,  Next: TeX Mode,  Prev: Text Mode,  Up: Text Mode

Nroff Mode
----------

   Nroff mode is a mode like Text mode but modified to handle nroff
commands present in the text.  Invoke `M-x nroff-mode' to enter this
mode.  Nroff mode differs from Text mode in only a few ways.  All nroff
command lines are considered paragraph separators, so that filling never
garbles the nroff commands.  Pages are separated by `.bp' commands.
Comments start with backslash-doublequote.  There are also three special
commands that are not available in Text mode:

`M-n'
     Move to the beginning of the next line that isn't an nroff command
     (`forward-text-line').  An argument is a repeat count.

`M-p'
     Like `M-n' but move up (`backward-text-line').

`M-?'
     Prints in the echo area the number of text lines (lines that are
     not nroff commands) in the region (`count-text-lines').

   The other feature of Nroff mode is Electric Nroff newline mode.
This is a minor mode that you can turn on or off with `M-x
electric-nroff-mode' (*note Minor Modes::).  When the mode is on and
you use <RET> to end a line containing an nroff command that opens a
kind of grouping, Emacs automatically inserts the matching nroff
command to close that grouping on the following line.  For example, if
you are at the beginning of a line and type `.(b <RET>', the matching
command `.)b' will be inserted on a new line following point.

   Entering Nroff mode calls the value of the variable `text-mode-hook'
with no arguments, if that value exists and is not `nil'; then it does
the same with the variable `nroff-mode-hook'.

\1f
File: xemacs.info,  Node: TeX Mode,  Next: Outline Mode,  Prev: Nroff Mode,  Up: Text Mode

TeX Mode
--------

   TeX is a powerful text formatter written by Donald Knuth; like GNU
Emacs, it is free.  LaTeX is a simplified input format for TeX,
implemented by TeX macros.  It is part of TeX.

   Emacs has a special TeX mode for editing TeX input files.  It
provides facilities for checking the balance of delimiters and for
invoking TeX on all or part of the file.

   TeX mode has two variants, Plain TeX mode and LaTeX mode, which are
two distinct major modes that differ only slightly.  These modes are
designed for editing the two different input formats.  The command `M-x
tex-mode' looks at the contents of a buffer to determine whether it
appears to be LaTeX input or not; it then selects the appropriate mode.
If it can't tell which is right (e.g., the buffer is empty), the
variable `tex-default-mode' controls which mode is used.

   The commands `M-x plain-tex-mode' and `M-x latex-mode' explicitly
select one of the variants of TeX mode.  Use these commands when `M-x
tex-mode' does not guess right.

* Menu:

* Editing: TeX Editing.   Special commands for editing in TeX mode.
* Printing: TeX Print.    Commands for printing part of a file with TeX.

   TeX for Unix systems can be obtained from the University of
Washington for a distribution fee.

   To order a full distribution, send $140.00 for a 1/2 inch 9-track
tape, $165.00 for two 4-track 1/4 inch cartridge tapes (foreign sites
$150.00, for 1/2 inch, $175.00 for 1/4 inch, to cover the extra
postage) payable to the University of Washington to:

     The Director
     Northwest Computer Support Group,  DW-10
     University of Washington
     Seattle, Washington 98195

Purchase orders are acceptable, but there is an extra charge of $10.00
to pay for processing charges. (The total cost comes to $150 for
domestic sites, $175 for foreign sites).

   The normal distribution is a tar tape, blocked 20, 1600 bpi, on an
industry standard 2400 foot half-inch reel.  The physical format for
the 1/4 inch streamer cartridges uses QIC-11, 8000 bpi, 4-track
serpentine recording for the SUN.  Also, SystemV tapes can be written
in cpio format, blocked 5120 bytes, ASCII headers.

\1f
File: xemacs.info,  Node: TeX Editing,  Next: TeX Print,  Prev: TeX Mode,  Up: TeX Mode

TeX Editing Commands
....................

   Here are the special commands provided in TeX mode for editing the
text of the file.

`"'
     Insert, according to context, either ```' or `"' or `'''
     (`TeX-insert-quote').

`<LFD>'
     Insert a paragraph break (two newlines) and check the previous
     paragraph for unbalanced braces or dollar signs (`tex-terminate-
     paragraph').

`M-x validate-tex-buffer'
     Check each paragraph in the buffer for unbalanced braces or dollar
     signs.

`C-c {'
     Insert `{}' and position point between them (`tex-insert-braces').

`C-c }'
     Move forward past the next unmatched close brace (`up-list').

`C-c C-e'
     Close a block for LaTeX (`tex-close-latex-block').

   In TeX, the character `"' is not normally used; you use ```' to
start a quotation and `''' to end one.  TeX mode defines the key `"' to
insert ```' after whitespace or an open brace, `"' after a backslash,
or `''' otherwise.  This is done by the command `tex-insert-quote'.  If
you need the character `"' itself in unusual contexts, use `C-q' to
insert it.  Also, `"' with a numeric argument always inserts that
number of `"' characters.

   In TeX mode, `$' has a special syntax code which attempts to
understand the way TeX math mode delimiters match.  When you insert a
`$' that is meant to exit math mode, the position of the matching `$'
that entered math mode is displayed for a second.  This is the same
feature that displays the open brace that matches a close brace that is
inserted.  However, there is no way to tell whether a `$' enters math
mode or leaves it; so when you insert a `$' that enters math mode, the
previous `$' position is shown as if it were a match, even though they
are actually unrelated.

   If you prefer to keep braces balanced at all times, you can use `C-c
{' (`tex-insert-braces') to insert a pair of braces.  It leaves point
between the two braces so you can insert the text that belongs inside.
Afterward, use the command `C-c }' (`up-list') to move forward past the
close brace.

   There are two commands for checking the matching of braces.  <LFD>
(`tex-terminate-paragraph') checks the paragraph before point, and
inserts two newlines to start a new paragraph.  It prints a message in
the echo area if any mismatch is found.  `M-x validate-tex-buffer'
checks the entire buffer, paragraph by paragraph.  When it finds a
paragraph that contains a mismatch, it displays point at the beginning
of the paragraph for a few seconds and pushes a mark at that spot.
Scanning continues until the whole buffer has been checked or until you
type another key.  The positions of the last several paragraphs with
mismatches can be found in the mark ring (*note Mark Ring::).

   Note that square brackets and parentheses, not just braces, are
matched in TeX mode.  This is wrong if you want to  check TeX syntax.
However, parentheses and square brackets are likely to be used in text
as matching delimiters and it is useful for the various motion commands
and automatic match display to work with them.

   In LaTeX input, `\begin' and `\end' commands must balance.  After
you insert a `\begin', use `C-c C-f' (`tex-close-latex-block') to
insert automatically a matching `\end' (on a new line following the
`\begin').  A blank line is inserted between the two, and point is left
there.