Trailing whitespace deleted.

[gnu-emacs] / man / text.texi

@c This is part of the Emacs manual.
@c Copyright (C) 1985,86,87,93,94,95,97,2000,2001, 2002
@c   Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Text, Programs, Indentation, Top
@chapter Commands for Human Languages
@cindex text
@cindex manipulating text

  The term @dfn{text} has two widespread meanings in our area of the
computer field.  One is data that is a sequence of characters.  Any file
that you edit with Emacs is text, in this sense of the word.  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/stylistic conventions that can be
supported or used to advantage by editor commands: conventions involving
words, sentences, paragraphs, and capital letters.  This chapter
describes Emacs commands for all of these things.  There are also
commands for @dfn{filling}, which means rearranging the lines of a
paragraph to be approximately equal in 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 the
file contains text pure and simple, use Text mode, which customizes
Emacs in small ways for the syntactic conventions of text.  Outline mode
provides special commands for operating on text with an outline
structure.
@iftex
@xref{Outline Mode}.
@end iftex

  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 would use @TeX{}
@iftex
mode (@pxref{TeX Mode}).
@end iftex
@ifinfo
mode.
@end ifinfo
For input to nroff, use Nroff mode.

  Instead of using a text formatter, you can edit formatted text in
WYSIWYG style (``what you see is what you get''), with Enriched mode.
Then the formatting appears on the screen in Emacs while you edit.
@iftex
@xref{Formatted Text}.
@end iftex

@cindex skeletons
@cindex templates
@cindex autotyping
@cindex automatic typing
  The ``automatic typing'' features may be useful when writing text.
@xref{Top,, Autotyping, autotype, Features for Automatic Typing}.

@menu
* 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.
* Text Mode::           The major modes for editing text files.
* Outline Mode::        Editing outlines.
* TeX Mode::            Editing input to the formatter TeX.
* HTML Mode::           Editing HTML, SGML, and XML files.
* Nroff Mode::          Editing input to the formatter nroff.
* Formatted Text::      Editing formatted text directly in WYSIWYG fashion.
@end menu

@node Words
@section Words
@cindex words
@cindex Meta commands and words

  Emacs has commands for moving over or operating on words.  By convention,
the keys for them are all Meta characters.

@table @kbd
@item M-f
Move forward over a word (@code{forward-word}).
@item M-b
Move backward over a word (@code{backward-word}).
@item M-d
Kill up to the end of a word (@code{kill-word}).
@item M-@key{DEL}
Kill back to the beginning of a word (@code{backward-kill-word}).
@item M-@@
Mark the end of the next word (@code{mark-word}).
@item M-t
Transpose two words or drag a word across other words
(@code{transpose-words}).
@end table

  Notice how these keys form a series that parallels the character-based
@kbd{C-f}, @kbd{C-b}, @kbd{C-d}, @key{DEL} and @kbd{C-t}.  @kbd{M-@@} is
cognate to @kbd{C-@@}, which is an alias for @kbd{C-@key{SPC}}.

@kindex M-f
@kindex M-b
@findex forward-word
@findex backward-word
  The commands @kbd{M-f} (@code{forward-word}) and @kbd{M-b}
(@code{backward-word}) move forward and backward over words.  These
Meta characters are thus analogous to the corresponding control
characters, @kbd{C-f} and @kbd{C-b}, which move over single characters
in the text.  The analogy extends to numeric arguments, which serve as
repeat counts.  @kbd{M-f} with a negative argument moves backward, and
@kbd{M-b} with a negative argument moves forward.  Forward motion
stops right after the last letter of the word, while backward motion
stops right before the first letter.@refill

@kindex M-d
@findex kill-word
  @kbd{M-d} (@code{kill-word}) kills the word after point.  To be
precise, it kills everything from point to the place @kbd{M-f} would
move to.  Thus, if point is in the middle of a word, @kbd{M-d} kills
just the part after point.  If some punctuation comes between point and the
next word, it is killed along with the word.  (If you wish to kill only the
next word but not the punctuation before it, simply do @kbd{M-f} to get
the end, and kill the word backwards with @kbd{M-@key{DEL}}.)
@kbd{M-d} takes arguments just like @kbd{M-f}.

@findex backward-kill-word
@kindex M-DEL
  @kbd{M-@key{DEL}} (@code{backward-kill-word}) kills the word before
point.  It kills everything from point back to where @kbd{M-b} would
move to.  If point is after the space in @w{@samp{FOO, BAR}}, then
@w{@samp{FOO, }} is killed.  (If you wish to kill just @samp{FOO}, and
not the comma and the space, use @kbd{M-b M-d} instead of
@kbd{M-@key{DEL}}.)

@c Don't index M-t and transpose-words here, they are indexed in
@c fixit.texi, in the node "Transpose".
@c @kindex M-t
@c @findex transpose-words
  @kbd{M-t} (@code{transpose-words}) exchanges the word before or
containing point with the following word.  The delimiter characters between
the words do not move.  For example, @w{@samp{FOO, BAR}} transposes into
@w{@samp{BAR, FOO}} rather than @samp{@w{BAR FOO,}}.  @xref{Transpose}, for
more on transposition and on arguments to transposition commands.

@kindex M-@@
@findex mark-word
  To operate on the next @var{n} words with an operation which applies
between point and mark, you can either set the mark at point and then move
over the words, or you can use the command @kbd{M-@@} (@code{mark-word})
which does not move point, but sets the mark where @kbd{M-f} would move
to.  @kbd{M-@@} accepts a numeric argument that says how many words to
scan for the place to put the mark.  In Transient Mark mode, this command
activates the mark.

  The word commands' understanding of syntax is completely controlled by
the syntax table.  Any character can, for example, be declared to be a word
delimiter.  @xref{Syntax}.

@node Sentences
@section Sentences
@cindex sentences
@cindex manipulating sentences

  The Emacs commands for manipulating sentences and paragraphs are mostly
on Meta keys, so as to be like the word-handling commands.

@table @kbd
@item M-a
Move back to the beginning of the sentence (@code{backward-sentence}).
@item M-e
Move forward to the end of the sentence (@code{forward-sentence}).
@item M-k
Kill forward to the end of the sentence (@code{kill-sentence}).
@item C-x @key{DEL}
Kill back to the beginning of the sentence (@code{backward-kill-sentence}).
@end table

@kindex M-a
@kindex M-e
@findex backward-sentence
@findex forward-sentence
  The commands @kbd{M-a} and @kbd{M-e} (@code{backward-sentence} and
@code{forward-sentence}) move to the beginning and end of the current
sentence, respectively.  They were chosen to resemble @kbd{C-a} and
@kbd{C-e}, which move to the beginning and end of a line.  Unlike them,
@kbd{M-a} and @kbd{M-e} if repeated or given numeric arguments move over
successive sentences.

  Moving backward over a sentence places point just before the first
character of the sentence; moving forward places point right after the
punctuation that ends the sentence.  Neither one moves over the
whitespace at the sentence boundary.

@kindex M-k
@kindex C-x DEL
@findex kill-sentence
@findex backward-kill-sentence
  Just as @kbd{C-a} and @kbd{C-e} have a kill command, @kbd{C-k}, to go
with them, so @kbd{M-a} and @kbd{M-e} have a corresponding kill command
@kbd{M-k} (@code{kill-sentence}) which kills from point to the end of
the sentence.  With minus one as an argument it kills back to the
beginning of the sentence.  Larger arguments serve as a repeat count.
There is also a command, @kbd{C-x @key{DEL}}
(@code{backward-kill-sentence}), for killing back to the beginning of a
sentence.  This command is useful when you change your mind in the
middle of composing text.@refill

  The sentence commands assume that you follow the American typist's
convention of putting two spaces at the end of a sentence; they consider
a sentence to end wherever there is a @samp{.}, @samp{?} or @samp{!}
followed by the end of a line or two spaces, with any number of
@samp{)}, @samp{]}, @samp{'}, or @samp{"} characters allowed in between.
A sentence also begins or ends wherever a paragraph begins or ends.

@vindex sentence-end
  The variable @code{sentence-end} controls recognition of the end of a
sentence.  It is a regexp that matches the last few characters of a
sentence, together with the whitespace following the sentence.  Its
normal value is

@example
"[.?!][]\"')]*\\($\\| $\\|\t\\|  \\)[ \t\n]*"
@end example

@noindent
This example is explained in the section on regexps.  @xref{Regexps}.

  If you want to use just one space between sentences, you should
set @code{sentence-end} to this value:

@example
"[.?!][]\"')]*\\($\\|\t\\| \\)[ \t\n]*"
@end example

@noindent
You should also set the variable @code{sentence-end-double-space} to
@code{nil} so that the fill commands expect and leave just one space at
the end of a sentence.  Note that this makes it impossible to
distinguish between periods that end sentences and those that indicate
abbreviations.

@node Paragraphs
@section Paragraphs
@cindex paragraphs
@cindex manipulating paragraphs
@kindex M-@{
@kindex M-@}
@findex backward-paragraph
@findex forward-paragraph

  The Emacs commands for manipulating paragraphs are also Meta keys.

@table @kbd
@item M-@{
Move back to previous paragraph beginning (@code{backward-paragraph}).
@item M-@}
Move forward to next paragraph end (@code{forward-paragraph}).
@item M-h
Put point and mark around this or next paragraph (@code{mark-paragraph}).
@end table

  @kbd{M-@{} moves to the beginning of the current or previous
paragraph, while @kbd{M-@}} moves to the end of the current or next
paragraph.  Blank lines and text-formatter command lines separate
paragraphs and are not considered part of any paragraph.  In Fundamental
mode, but not in Text mode, an indented line also starts a new
paragraph.  (If a paragraph is preceded by a blank line, these commands
treat that blank line as the beginning of the paragraph.)

  In major modes for programs, paragraphs begin and end only at blank
lines.  This makes the paragraph commands continue to be useful even
though there are no paragraphs per se.

  When there is a fill prefix, then paragraphs are delimited by all lines
which don't start with the fill prefix.  @xref{Filling}.

@kindex M-h
@findex mark-paragraph
  When you wish to operate on a paragraph, you can use the command
@kbd{M-h} (@code{mark-paragraph}) to set the region around it.  Thus,
for example, @kbd{M-h C-w} kills the paragraph around or after point.
The @kbd{M-h} command puts point at the beginning and mark at the end of
the paragraph point was in.  In Transient Mark mode, it activates the
mark.  If point is between paragraphs (in a run of blank lines, or at a
boundary), the paragraph following point is surrounded by point and
mark.  If there are blank lines preceding the first line of the
paragraph, one of these blank lines is included in the region.

@vindex paragraph-start
@vindex paragraph-separate
  The precise definition of a paragraph boundary is controlled by the
variables @code{paragraph-separate} and @code{paragraph-start}.  The
value of @code{paragraph-start} is a regexp that should match any line
that either starts or separates paragraphs.  The value of
@code{paragraph-separate} is another regexp that should match only lines
that separate paragraphs without being part of any paragraph (for
example, blank lines).  Lines that start a new paragraph and are
contained in it must match only @code{paragraph-start}, not
@code{paragraph-separate}.  For example, in Fundamental mode,
@code{paragraph-start} is @w{@code{"[ \t\n\f]"}}, and
@code{paragraph-separate} is @w{@code{"[ \t\f]*$"}}.

  Normally it is desirable for page boundaries to separate paragraphs.
The default values of these variables recognize the usual separator for
pages.

@node Pages
@section Pages

@cindex pages
@cindex formfeed
  Files are often thought of as divided into @dfn{pages} by the
@dfn{formfeed} character (ASCII control-L, octal code 014).  When you
print hardcopy for a file, this character forces a page break; thus,
each page of the file goes on a separate page on paper.  Most Emacs
commands treat the page-separator character just like any other
character: you can insert it with @kbd{C-q C-l}, and delete it with
@key{DEL}.  Thus, you are free to paginate your file or not.  However,
since pages are often meaningful divisions of the file, Emacs provides
commands to move over them and operate on them.

@table @kbd
@item C-x [
Move point to previous page boundary (@code{backward-page}).
@item C-x ]
Move point to next page boundary (@code{forward-page}).
@item C-x C-p
Put point and mark around this page (or another page) (@code{mark-page}).
@item C-x l
Count the lines in this page (@code{count-lines-page}).
@end table

@kindex C-x [
@kindex C-x ]
@findex forward-page
@findex backward-page
  The @kbd{C-x [} (@code{backward-page}) command moves point to immediately
after the previous page delimiter.  If point is already right after a page
delimiter, it skips that one and stops at the previous one.  A numeric
argument serves as a repeat count.  The @kbd{C-x ]} (@code{forward-page})
command moves forward past the next page delimiter.

@kindex C-x C-p
@findex mark-page
  The @kbd{C-x C-p} command (@code{mark-page}) puts point at the
beginning of the current page and the mark at the end.  The page
delimiter at the end is included (the mark follows it).  The page
delimiter at the front is excluded (point follows it).  In Transient
Mark mode, this command activates the mark.

  @kbd{C-x C-p C-w} is a handy way to kill a page to move it
elsewhere.  If you move to another page delimiter with @kbd{C-x [} and
@kbd{C-x ]}, then yank the killed page, all the pages will be properly
delimited once again.  The reason @kbd{C-x C-p} includes only the
following page delimiter in the region is to ensure that.

  A numeric argument to @kbd{C-x C-p} is used to specify which page to go
to, relative to the current one.  Zero means the current page.  One means
the next page, and @minus{}1 means the previous one.

@kindex C-x l
@findex count-lines-page
  The @kbd{C-x l} command (@code{count-lines-page}) is good for deciding
where to break a page in two.  It displays in the echo area the total number
of lines in the current page, and then divides it up into those preceding
the current line and those following, as in

@example
Page has 96 (72+25) lines
@end example

@noindent
  Notice that the sum is off by one; this is correct if point is not at the
beginning of a line.

@vindex page-delimiter
  The variable @code{page-delimiter} controls where pages begin.  Its
value is a regexp that matches the beginning of a line that separates
pages.  The normal value of this variable is @code{"^\f"}, which
matches a formfeed character at the beginning of a line.

@node Filling
@section Filling Text
@cindex filling text

  @dfn{Filling} text means breaking it up into lines that fit a
specified width.  Emacs does filling in two ways.  In Auto Fill mode,
inserting text with self-inserting characters also automatically fills
it.  There are also explicit fill commands that you can use when editing
text leaves it unfilled.  When you edit formatted text, you can specify
a style of filling for each portion of the text (@pxref{Formatted
Text}).

@menu
* Auto Fill::           Auto Fill mode breaks long lines automatically.
* Refill::              Keeping paragraphs filled.
* Fill Commands::       Commands to refill paragraphs and center lines.
* Fill Prefix::         Filling paragraphs that are indented
                          or in a comment, etc.
* Adaptive Fill::       How Emacs can determine the fill prefix automatically.
@end menu

@node Auto Fill
@subsection Auto Fill Mode
@cindex Auto Fill mode
@cindex mode, Auto Fill
@cindex word wrap

  @dfn{Auto Fill} mode is a minor mode in which lines are broken
automatically when they become too wide.  Breaking happens only when
you type a @key{SPC} or @key{RET}.

@table @kbd
@item M-x auto-fill-mode
Enable or disable Auto Fill mode.
@item @key{SPC}
@itemx @key{RET}
In Auto Fill mode, break lines when appropriate.
@end table

@findex auto-fill-mode
  @kbd{M-x auto-fill-mode} turns Auto Fill mode on if it was off, or off
if it was on.  With a positive numeric argument it always turns Auto
Fill mode on, and with a negative argument always turns it off.  You can
see when Auto Fill mode is in effect by the presence of the word
@samp{Fill} in the mode line, inside the parentheses.  Auto Fill mode is
a minor mode which is enabled or disabled for each buffer individually.
@xref{Minor Modes}.

  In Auto Fill mode, lines are broken automatically at spaces when they
get longer than the desired width.  Line breaking and rearrangement
takes place only when you type @key{SPC} or @key{RET}.  If you wish to
insert a space or newline without permitting line-breaking, type
@kbd{C-q @key{SPC}} or @kbd{C-q C-j} (recall that a newline is really a
control-J).  Also, @kbd{C-o} inserts a newline without line breaking.

  Auto Fill mode works well with programming-language modes, because it
indents new lines with @key{TAB}.  If a line ending in a comment gets
too long, the text of the comment is split into two comment lines.
Optionally, new comment delimiters are inserted at the end of the first
line and the beginning of the second so that each line is a separate
comment; the variable @code{comment-multi-line} controls the choice
(@pxref{Comments}).

  Adaptive filling (@pxref{Adaptive Fill}) works for Auto Filling as
well as for explicit fill commands.  It takes a fill prefix
automatically from the second or first line of a paragraph.

  Auto Fill mode does not refill entire paragraphs; it can break lines but
cannot merge lines.  So editing in the middle of a paragraph can result in
a paragraph that is not correctly filled.  The easiest way to make the
paragraph properly filled again is usually with the explicit fill commands.
@ifinfo
@xref{Fill Commands}.
@end ifinfo

  Many users like Auto Fill mode and want to use it in all text files.
The section on init files says how to arrange this permanently for yourself.
@xref{Init File}.

@node Refill
@subsection Refill Mode
@cindex refilling text, word processor style
@cindex modes, Refill
@cindex Refill minor mode

  Refill minor mode provides support for keeping paragraphs filled as
you type or modify them in other ways.  It provides an effect similar
to typical word processor behavior.  This works by running a
paragraph-filling command at suitable times.

  When you are typing text, only characters which normally trigger
auto filling, like the space character, will trigger refilling.  This
is to avoid making it too slow.  Apart from self-inserting characters,
other commands which modify the text cause refilling.

  The current implementation is preliminary and probably not robust.
We expect to improve on it.

  To toggle the use of Refill mode in the current buffer, type
@kbd{M-x refill-mode}.

@node Fill Commands
@subsection Explicit Fill Commands

@table @kbd
@item M-q
Fill current paragraph (@code{fill-paragraph}).
@item C-x f
Set the fill column (@code{set-fill-column}).
@item M-x fill-region
Fill each paragraph in the region (@code{fill-region}).
@item M-x fill-region-as-paragraph
Fill the region, considering it as one paragraph.
@item M-s
Center a line.
@end table

@kindex M-q
@findex fill-paragraph
  To refill a paragraph, use the command @kbd{M-q}
(@code{fill-paragraph}).  This operates on the paragraph that point is
inside, or the one after point if point is between paragraphs.
Refilling works by removing all the line-breaks, then inserting new ones
where necessary.

@findex fill-region
  To refill many paragraphs, use @kbd{M-x fill-region}, which
divides the region into paragraphs and fills each of them.

@findex fill-region-as-paragraph
  @kbd{M-q} and @code{fill-region} use the same criteria as @kbd{M-h}
for finding paragraph boundaries (@pxref{Paragraphs}).  For more
control, you can use @kbd{M-x fill-region-as-paragraph}, which refills
everything between point and mark.  This command deletes any blank lines
within the region, so separate blocks of text end up combined into one
block.@refill

@cindex justification
  A numeric argument to @kbd{M-q} causes it to @dfn{justify} the text as
well as filling it.  This means that extra spaces are inserted to make
the right margin line up exactly at the fill column.  To remove the
extra spaces, use @kbd{M-q} with no argument.  (Likewise for
@code{fill-region}.)  Another way to control justification, and choose
other styles of filling, is with the @code{justification} text property;
see @ref{Format Justification}.

@kindex M-s @r{(Text mode)}
@cindex centering
@findex center-line
  The command @kbd{M-s} (@code{center-line}) centers the current line
within the current fill column.  With an argument @var{n}, it centers
@var{n} lines individually and moves past them.

@vindex fill-column
@kindex C-x f
@findex set-fill-column
  The maximum line width for filling is in the variable
@code{fill-column}.  Altering the value of @code{fill-column} makes it
local to the current buffer; until that time, the default value is in
effect.  The default is initially 70.  @xref{Locals}.  The easiest way
to set @code{fill-column} is to use the command @kbd{C-x f}
(@code{set-fill-column}).  With a numeric argument, it uses that as the
new fill column.  With just @kbd{C-u} as argument, it sets
@code{fill-column} to the current horizontal position of point.

  Emacs commands normally consider a period followed by two spaces or by
a newline as the end of a sentence; a period followed by just one space
indicates an abbreviation and not the end of a sentence.  To preserve
the distinction between these two ways of using a period, the fill
commands do not break a line after a period followed by just one space.

@vindex sentence-end-double-space
  If the variable @code{sentence-end-double-space} is @code{nil}, the
fill commands expect and leave just one space at the end of a sentence.
Ordinarily this variable is @code{t}, so the fill commands insist on
two spaces for the end of a sentence, as explained above.  @xref{Sentences}.

@vindex colon-double-space
  If the variable @code{colon-double-space} is non-@code{nil}, the
fill commands put two spaces after a colon.

@vindex sentence-end-without-period
  Some languages do not use period to indicate end of sentence.  For
example, a sentence in Thai text ends with double space but without a
period.  Set the variable @code{sentence-end-without-period} to
@code{t} to tell the sentence commands that a period is not necessary.

@vindex fill-nobreak-predicate
  The variable @code{fill-nobreak-predicate} specifies additional
conditions for where line-breaking is allowed.  Its value is either
@code{nil} or a Lisp function; the function is called with no
arguments, and if it returns a non-@code{nil} value, then point is not
a good place to break the line.  The standard functions you can use
@code{fill-single-word-nobreak-p} (don't break after the first word of
a sentence or before the last) and @code{fill-french-nobreak-p} (don't
break after @samp{(} or before @samp{)}, @samp{:} or @samp{?}).

@node Fill Prefix
@subsection The Fill Prefix

@cindex fill prefix
  To fill a paragraph in which each line starts with a special marker
(which might be a few spaces, giving an indented paragraph), you can use
the @dfn{fill prefix} feature.  The fill prefix is a string that Emacs
expects every line to start with, and which is not included in filling.
You can specify a fill prefix explicitly; Emacs can also deduce the
fill prefix automatically (@pxref{Adaptive Fill}).

@table @kbd
@item C-x .
Set the fill prefix (@code{set-fill-prefix}).
@item M-q
Fill a paragraph using current fill prefix (@code{fill-paragraph}).
@item M-x fill-individual-paragraphs
Fill the region, considering each change of indentation as starting a
new paragraph.
@item M-x fill-nonuniform-paragraphs
Fill the region, considering only paragraph-separator lines as starting
a new paragraph.
@end table

@kindex C-x .
@findex set-fill-prefix
  To specify a fill prefix, move to a line that starts with the desired
prefix, put point at the end of the prefix, and give the command
@w{@kbd{C-x .}}@: (@code{set-fill-prefix}).  That's a period after the
@kbd{C-x}.  To turn off the fill prefix, specify an empty prefix: type
@w{@kbd{C-x .}}@: with point at the beginning of a line.@refill

  When a fill prefix is in effect, the fill commands remove the fill
prefix from each line before filling and insert it on each line after
filling.  Auto Fill mode also inserts the fill prefix automatically when
it makes a new line.  The @kbd{C-o} command inserts the fill prefix on
new lines it creates, when you use it at the beginning of a line
(@pxref{Blank Lines}).  Conversely, the command @kbd{M-^} deletes the
prefix (if it occurs) after the newline that it deletes
(@pxref{Indentation}).

  For example, if @code{fill-column} is 40 and you set the fill prefix
to @samp{;; }, then @kbd{M-q} in the following text

@example
;; This is an
;; example of a paragraph
;; inside a Lisp-style comment.
@end example

@noindent
produces this:

@example
;; This is an example of a paragraph
;; inside a Lisp-style comment.
@end example

  Lines that do not start with the fill prefix are considered to start
paragraphs, both in @kbd{M-q} and the paragraph commands; this gives
good results for paragraphs with hanging indentation (every line
indented except the first one).  Lines which are blank or indented once
the prefix is removed also separate or start paragraphs; this is what
you want if you are writing multi-paragraph comments with a comment
delimiter on each line.

@findex fill-individual-paragraphs
  You can use @kbd{M-x fill-individual-paragraphs} to set the fill
prefix for each paragraph automatically.  This command divides the
region into paragraphs, treating every change in the amount of
indentation as the start of a new paragraph, and fills each of these
paragraphs.  Thus, all the lines in one ``paragraph'' have the same
amount of indentation.  That indentation serves as the fill prefix for
that paragraph.

@findex fill-nonuniform-paragraphs
  @kbd{M-x fill-nonuniform-paragraphs} is a similar command that divides
the region into paragraphs in a different way.  It considers only
paragraph-separating lines (as defined by @code{paragraph-separate}) as
starting a new paragraph.  Since this means that the lines of one
paragraph may have different amounts of indentation, the fill prefix
used is the smallest amount of indentation of any of the lines of the
paragraph.  This gives good results with styles that indent a paragraph's
first line more or less that the rest of the paragraph.

@vindex fill-prefix
  The fill prefix is stored in the variable @code{fill-prefix}.  Its value
is a string, or @code{nil} when there is no fill prefix.  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.  @xref{Locals}.

  The @code{indentation} text property provides another way to control
the amount of indentation paragraphs receive.  @xref{Format Indentation}.

@node Adaptive Fill
@subsection Adaptive Filling

@cindex adaptive filling
  The fill commands can deduce the proper fill prefix for a paragraph
automatically in certain cases: either whitespace or certain punctuation
characters at the beginning of a line are propagated to all lines of the
paragraph.

  If the paragraph has two or more lines, the fill prefix is taken from
the paragraph's second line, but only if it appears on the first line as
well.

  If a paragraph has just one line, fill commands @emph{may} take a
prefix from that line.  The decision is complicated because there are
three reasonable things to do in such a case:

@itemize @bullet
@item
Use the first line's prefix on all the lines of the paragraph.

@item
Indent subsequent lines with whitespace, so that they line up under the
text that follows the prefix on the first line, but don't actually copy
the prefix from the first line.

@item
Don't do anything special with the second and following lines.
@end itemize

  All three of these styles of formatting are commonly used.  So the
fill commands try to determine what you would like, based on the prefix
that appears and on the major mode.  Here is how.

@vindex adaptive-fill-first-line-regexp
  If the prefix found on the first line matches
@code{adaptive-fill-first-line-regexp}, or if it appears to be a
comment-starting sequence (this depends on the major mode), then the
prefix found is used for filling the paragraph, provided it would not
act as a paragraph starter on subsequent lines.

  Otherwise, the prefix found is converted to an equivalent number of
spaces, and those spaces are used as the fill prefix for the rest of the
lines, provided they would not act as a paragraph starter on subsequent
lines.

  In Text mode, and other modes where only blank lines and page
delimiters separate paragraphs, the prefix chosen by adaptive filling
never acts as a paragraph starter, so it can always be used for filling.

@vindex adaptive-fill-mode
@vindex adaptive-fill-regexp
  The variable @code{adaptive-fill-regexp} determines what kinds of line
beginnings can serve as a fill prefix: any characters at the start of
the line that match this regular expression are used.  If you set the
variable @code{adaptive-fill-mode} to @code{nil}, the fill prefix is
never chosen automatically.

@vindex adaptive-fill-function
  You can specify more complex ways of choosing a fill prefix
automatically by setting the variable @code{adaptive-fill-function} to a
function.  This function is called with point after the left margin of a
line, and it should return the appropriate fill prefix based on that
line.  If it returns @code{nil}, that means it sees no fill prefix in
that line.

@node Case
@section Case Conversion Commands
@cindex case conversion

  Emacs has commands for converting either a single word or any arbitrary
range of text to upper case or to lower case.

@table @kbd
@item M-l
Convert following word to lower case (@code{downcase-word}).
@item M-u
Convert following word to upper case (@code{upcase-word}).
@item M-c
Capitalize the following word (@code{capitalize-word}).
@item C-x C-l
Convert region to lower case (@code{downcase-region}).
@item C-x C-u
Convert region to upper case (@code{upcase-region}).
@end table

@kindex M-l
@kindex M-u
@kindex M-c
@cindex words, case conversion
@cindex converting text to upper or lower case
@cindex capitalizing words
@findex downcase-word
@findex upcase-word
@findex capitalize-word
  The word conversion commands are the most useful.  @kbd{M-l}
(@code{downcase-word}) converts the word after point to lower case, moving
past it.  Thus, repeating @kbd{M-l} converts successive words.
@kbd{M-u} (@code{upcase-word}) converts to all capitals instead, while
@kbd{M-c} (@code{capitalize-word}) puts the first letter of the word
into upper case and the rest into lower case.  All these commands convert
several words at once if given an argument.  They are especially convenient
for converting a large amount of text from all upper case to mixed case,
because you can move through the text using @kbd{M-l}, @kbd{M-u} or
@kbd{M-c} on each word as appropriate, occasionally using @kbd{M-f} instead
to skip a word.

  When given a negative argument, the word case conversion commands apply
to the appropriate number of words before point, but do not move point.
This is convenient when you have just typed a word in the wrong case: you
can give the case conversion command and continue typing.

  If a word case conversion command is given in the middle of a word, it
applies only to the part of the word which follows point.  This is just
like what @kbd{M-d} (@code{kill-word}) does.  With a negative argument,
case conversion applies only to the part of the word before point.

@kindex C-x C-l
@kindex C-x C-u
@findex downcase-region
@findex upcase-region
  The other case conversion commands are @kbd{C-x C-u}
(@code{upcase-region}) and @kbd{C-x C-l} (@code{downcase-region}), which
convert everything between point and mark to the specified case.  Point and
mark do not move.

  The region case conversion commands @code{upcase-region} and
@code{downcase-region} are normally disabled.  This means that they ask
for confirmation if you try to use them.  When you confirm, you may
enable the command, which means it will not ask for confirmation again.
@xref{Disabling}.

@node Text Mode
@section Text Mode
@cindex Text mode
@cindex mode, Text
@findex text-mode

  When you edit files of text in a human language, it's more convenient
to use Text mode rather than Fundamental mode.  To enter Text mode, type
@kbd{M-x text-mode}.

  In Text mode, only blank lines and page delimiters separate
paragraphs.  As a result, paragraphs can be indented, and adaptive
filling determines what indentation to use when filling a paragraph.
@xref{Adaptive Fill}.

@kindex TAB @r{(Text mode)}
  Text mode defines @key{TAB} to run @code{indent-relative}
(@pxref{Indentation}), so that you can conveniently indent a line like
the previous line.  When the previous line is not indented,
@code{indent-relative} runs @code{tab-to-tab-stop}, which uses Emacs tab
stops that you can set (@pxref{Tab Stops}).

  Text mode turns off the features concerned with comments except when
you explicitly invoke them.  It changes the syntax table so that periods
are not considered part of a word, while apostrophes, backspaces and
underlines are considered part of words.

@cindex Paragraph-Indent Text mode
@cindex mode, Paragraph-Indent Text
@findex paragraph-indent-text-mode
@findex paragraph-indent-minor-mode
  If you indent the first lines of paragraphs, then you should use
Paragraph-Indent Text mode rather than Text mode.  In this mode, you do
not need to have blank lines between paragraphs, because the first-line
indentation is sufficient to start a paragraph; however paragraphs in
which every line is indented are not supported.  Use @kbd{M-x
paragraph-indent-text-mode} to enter this mode.  Use @kbd{M-x
paragraph-indent-minor-mode} to enter an equivalent minor mode, for
instance during mail composition.

@kindex M-TAB @r{(Text mode)}
  Text mode, and all the modes based on it, define @kbd{M-@key{TAB}} as
the command @code{ispell-complete-word}, which performs completion of
the partial word in the buffer before point, using the spelling
dictionary as the space of possible words.  @xref{Spelling}.

@vindex text-mode-hook
  Entering Text mode runs the hook @code{text-mode-hook}.  Other major
modes related to Text mode also run this hook, followed by hooks of
their own; this includes Paragraph-Indent Text mode, Nroff mode, @TeX{}
mode, Outline mode, and Mail mode.  Hook functions on
@code{text-mode-hook} can look at the value of @code{major-mode} to see
which of these modes is actually being entered.  @xref{Hooks}.

@ifinfo
  Emacs provides two other modes for editing text that is to be passed
through a text formatter to produce fancy formatted printed output.
@xref{Nroff Mode}, for editing input to the formatter nroff.
@xref{TeX Mode}, for editing input to the formatter TeX.

  Another 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.  @xref{Outline Mode}.
@end ifinfo

@node Outline Mode
@section Outline Mode
@cindex Outline mode
@cindex mode, Outline
@cindex invisible lines

@findex outline-mode
@findex outline-minor-mode
@vindex outline-minor-mode-prefix
  Outline mode is a major mode much like Text mode but intended for
editing outlines.  It allows you to make parts of the text temporarily
invisible so that you can see the outline structure.  Type @kbd{M-x
outline-mode} to switch to Outline mode as the major mode of the current
buffer.

  When Outline mode makes a line invisible, the line does not appear on
the screen.  The screen appears exactly as if the invisible line were
deleted, except that an ellipsis (three periods in a row) appears at the
end of the previous visible line (only one ellipsis no matter how many
invisible lines follow).

  Editing commands that operate on lines, such as @kbd{C-n} and
@kbd{C-p}, treat the text of the invisible line as part of the previous
visible line.  Killing an entire visible line, including its terminating
newline, really kills all the following invisible lines along with it.

  Outline minor mode provides the same commands as the major mode,
Outline mode, but you can use it in conjunction with other major modes.
Type @kbd{M-x outline-minor-mode} to enable the Outline minor mode in
the current buffer.  You can also specify this in the text of a file,
with a file local variable of the form @samp{mode: outline-minor}
(@pxref{File Variables}).

@kindex C-c @@ @r{(Outline minor mode)}
  The major mode, Outline mode, provides special key bindings on the
@kbd{C-c} prefix.  Outline minor mode provides similar bindings with
@kbd{C-c @@} as the prefix; this is to reduce the conflicts with the
major mode's special commands.  (The variable
@code{outline-minor-mode-prefix} controls the prefix used.)

@vindex outline-mode-hook
  Entering Outline mode runs the hook @code{text-mode-hook} followed by
the hook @code{outline-mode-hook} (@pxref{Hooks}).

@menu
* Format: Outline Format.          What the text of an outline looks like.
* Motion: Outline Motion.          Special commands for moving through
                                     outlines.
* Visibility: Outline Visibility.  Commands to control what is visible.
* Views: Outline Views.            Outlines and multiple views.
* Foldout::                        Folding editing.
@end menu

@node Outline Format
@subsection Format of Outlines

@cindex heading lines (Outline mode)
@cindex body lines (Outline mode)
  Outline mode assumes that the lines in the buffer are of two types:
@dfn{heading lines} and @dfn{body lines}.  A heading line represents a
topic in the outline.  Heading lines start with one or more stars; the
number of stars determines the depth of the heading in the outline
structure.  Thus, a heading line with one star is a major topic; all the
heading lines with two stars between it and the next one-star heading
are its subtopics; and so on.  Any line that is not a heading line is a
body line.  Body lines belong with the preceding heading line.  Here is
an example:

@example
* Food
This is the body,
which says something about the topic of food.

** Delicious Food
This is the body of the second-level header.

** Distasteful Food
This could have
a body too, with
several lines.

*** Dormitory Food

* Shelter
Another first-level topic with its header line.
@end example

  A heading line together with all following body lines is called
collectively an @dfn{entry}.  A heading line together with all following
deeper heading lines and their body lines is called a @dfn{subtree}.

@vindex outline-regexp
  You can customize the criterion for distinguishing heading lines
by setting the variable @code{outline-regexp}.  Any line whose
beginning has a match for this regexp is considered a heading line.
Matches that start within a line (not at the left margin) do not count.
The length of the matching text determines the level of the heading;
longer matches make a more deeply nested level.  Thus, for example,
if a text formatter has commands @samp{@@chapter}, @samp{@@section}
and @samp{@@subsection} to divide the document into chapters and
sections, you could make those lines count as heading lines by
setting @code{outline-regexp} to @samp{"@@chap\\|@@\\(sub\\)*section"}.
Note the trick: the two words @samp{chapter} and @samp{section} are equally
long, but by defining the regexp to match only @samp{chap} we ensure
that the length of the text matched on a chapter heading is shorter,
so that Outline mode will know that sections are contained in chapters.
This works as long as no other command starts with @samp{@@chap}.

@vindex outline-level
  You can change the rule for calculating the level of a heading line
by setting the variable @code{outline-level}.  The value of
@code{outline-level} should be a function that takes no arguments and
returns the level of the current heading.  Some major modes such as C,
Nroff, and Emacs Lisp mode set this variable and @code{outline-regexp}
in order to work with Outline minor mode.

@node Outline Motion
@subsection Outline Motion Commands

  Outline mode provides special motion commands that move backward and
forward to heading lines.

@table @kbd
@item C-c C-n
Move point to the next visible heading line
(@code{outline-next-visible-heading}).
@item C-c C-p
Move point to the previous visible heading line
(@code{outline-previous-visible-heading}).
@item C-c C-f
Move point to the next visible heading line at the same level
as the one point is on (@code{outline-forward-same-level}).
@item C-c C-b
Move point to the previous visible heading line at the same level
(@code{outline-backward-same-level}).
@item C-c C-u
Move point up to a lower-level (more inclusive) visible heading line
(@code{outline-up-heading}).
@end table

@findex outline-next-visible-heading
@findex outline-previous-visible-heading
@kindex C-c C-n @r{(Outline mode)}
@kindex C-c C-p @r{(Outline mode)}
  @kbd{C-c C-n} (@code{outline-next-visible-heading}) moves down to the next
heading line.  @kbd{C-c C-p} (@code{outline-previous-visible-heading}) moves
similarly backward.  Both accept numeric arguments as repeat counts.  The
names emphasize that invisible headings are skipped, but this is not really
a special feature.  All editing commands that look for lines ignore the
invisible lines automatically.@refill

@findex outline-up-heading
@findex outline-forward-same-level
@findex outline-backward-same-level
@kindex C-c C-f @r{(Outline mode)}
@kindex C-c C-b @r{(Outline mode)}
@kindex C-c C-u @r{(Outline mode)}
  More powerful motion commands understand the level structure of headings.
@kbd{C-c C-f} (@code{outline-forward-same-level}) and
@kbd{C-c C-b} (@code{outline-backward-same-level}) move from one
heading line to another visible heading at the same depth in
the outline.  @kbd{C-c C-u} (@code{outline-up-heading}) moves
backward to another heading that is less deeply nested.

@node Outline Visibility
@subsection Outline Visibility Commands

  The other special commands of outline mode are used to make lines visible
or invisible.  Their names all start with @code{hide} or @code{show}.
Most of them fall into pairs of opposites.  They are not undoable; instead,
you can undo right past them.  Making lines visible or invisible is simply
not recorded by the undo mechanism.

@table @kbd
@item C-c C-t
Make all body lines in the buffer invisible (@code{hide-body}).
@item C-c C-a
Make all lines in the buffer visible (@code{show-all}).
@item C-c C-d
Make everything under this heading invisible, not including this
heading itself (@code{hide-subtree}).
@item C-c C-s
Make everything under this heading visible, including body,
subheadings, and their bodies (@code{show-subtree}).
@item C-c C-l
Make the body of this heading line, and of all its subheadings,
invisible (@code{hide-leaves}).
@item C-c C-k
Make all subheadings of this heading line, at all levels, visible
(@code{show-branches}).
@item C-c C-i
Make immediate subheadings (one level down) of this heading line
visible (@code{show-children}).
@item C-c C-c
Make this heading line's body invisible (@code{hide-entry}).
@item C-c C-e
Make this heading line's body visible (@code{show-entry}).
@item C-c C-q
Hide everything except the top @var{n} levels of heading lines
(@code{hide-sublevels}).
@item C-c C-o
Hide everything except for the heading or body that point is in, plus
the headings leading up from there to the top level of the outline
(@code{hide-other}).
@end table

@findex hide-entry
@findex show-entry
@kindex C-c C-c @r{(Outline mode)}
@kindex C-c C-e @r{(Outline mode)}
  Two commands that are exact opposites are @kbd{C-c C-c}
(@code{hide-entry}) and @kbd{C-c C-e} (@code{show-entry}).  They are
used with point on a heading line, and apply only to the body lines of
that heading.  Subheadings and their bodies are not affected.

@findex hide-subtree
@findex show-subtree
@kindex C-c C-s @r{(Outline mode)}
@kindex C-c C-d @r{(Outline mode)}
@cindex subtree (Outline mode)
  Two more powerful opposites are @kbd{C-c C-d} (@code{hide-subtree}) and
@kbd{C-c C-s} (@code{show-subtree}).  Both expect to be used when point is
on a heading line, and both apply to all the lines of that heading's
@dfn{subtree}: its body, all its subheadings, both direct and indirect, and
all of their bodies.  In other words, the subtree contains everything
following this heading line, up to and not including the next heading of
the same or higher rank.@refill

@findex hide-leaves
@findex show-branches
@kindex C-c C-l @r{(Outline mode)}
@kindex C-c C-k @r{(Outline mode)}
  Intermediate between a visible subtree and an invisible one is having
all the subheadings visible but none of the body.  There are two
commands for doing this, depending on whether you want to hide the
bodies or make the subheadings visible.  They are @kbd{C-c C-l}
(@code{hide-leaves}) and @kbd{C-c C-k} (@code{show-branches}).

@kindex C-c C-i @r{(Outline mode)}
@findex show-children
  A little weaker than @code{show-branches} is @kbd{C-c C-i}
(@code{show-children}).  It makes just the direct subheadings
visible---those one level down.  Deeper subheadings remain invisible, if
they were invisible.@refill

@findex hide-body
@findex show-all
@kindex C-c C-t @r{(Outline mode)}
@kindex C-c C-a @r{(Outline mode)}
  Two commands have a blanket effect on the whole file.  @kbd{C-c C-t}
(@code{hide-body}) makes all body lines invisible, so that you see just
the outline structure.  @kbd{C-c C-a} (@code{show-all}) makes all lines
visible.  These commands can be thought of as a pair of opposites even
though @kbd{C-c C-a} applies to more than just body lines.

@findex hide-sublevels
@kindex C-c C-q @r{(Outline mode)}
  The command @kbd{C-c C-q} (@code{hide-sublevels}) hides all but the
top level headings.  With a numeric argument @var{n}, it hides everything
except the top @var{n} levels of heading lines.

@findex hide-other
@kindex C-c C-o @r{(Outline mode)}
  The command @kbd{C-c C-o} (@code{hide-other}) hides everything except
the heading or body text that point is in, plus its parents (the headers
leading up from there to top level in the outline).

  You can turn off the use of ellipses at the ends of visible lines by
setting @code{selective-display-ellipses} to @code{nil}.  Then there is
no visible indication of the presence of invisible lines.

@findex reveal-mode
  When incremental search finds text that is hidden by Outline mode,
it makes that part of the buffer visible.  If you exit the search
at that position, the text remains visible.  You can also
automatically make text visible as you navigate in it by using
@kbd{M-x reveal-mode}.

@node Outline Views
@subsection Viewing One Outline in Multiple Views

@cindex multiple views of outline
@cindex views of an outline
@cindex outline with multiple views
@cindex indirect buffers and outlines
  You can display two views of a single outline at the same time, in
different windows.  To do this, you must create an indirect buffer using
@kbd{M-x make-indirect-buffer}.  The first argument of this command is
the existing outline buffer name, and its second argument is the name to
use for the new indirect buffer.  @xref{Indirect Buffers}.

  Once the indirect buffer exists, you can display it in a window in the
normal fashion, with @kbd{C-x 4 b} or other Emacs commands.  The Outline
mode commands to show and hide parts of the text operate on each buffer
independently; as a result, each buffer can have its own view.  If you
want more than two views on the same outline, create additional indirect
buffers.

@node Foldout
@subsection Folding Editing

@cindex folding editing
  The Foldout package extends Outline mode and Outline minor mode with
``folding'' commands.  The idea of folding is that you zoom in on a
nested portion of the outline, while hiding its relatives at higher
levels.

  Consider an Outline mode buffer all the text and subheadings under
level-1 headings hidden.  To look at what is hidden under one of these
headings, you could use @kbd{C-c C-e} (@kbd{M-x show-entry}) to expose
the body, or @kbd{C-c C-i} to expose the child (level-2) headings.

@kindex C-c C-z
@findex foldout-zoom-subtree
  With Foldout, you use @kbd{C-c C-z} (@kbd{M-x foldout-zoom-subtree}).
This exposes the body and child subheadings, and narrows the buffer so
that only the @w{level-1} heading, the body and the level-2 headings are
visible.  Now to look under one of the level-2 headings, position the
cursor on it and use @kbd{C-c C-z} again.  This exposes the level-2 body
and its level-3 child subheadings and narrows the buffer again.  Zooming
in on successive subheadings can be done as much as you like.  A string
in the mode line shows how deep you've gone.

  When zooming in on a heading, to see only the child subheadings specify
a numeric argument: @kbd{C-u C-c C-z}.  The number of levels of children
can be specified too (compare @kbd{M-x show-children}), e.g.@: @kbd{M-2
C-c C-z} exposes two levels of child subheadings.  Alternatively, the
body can be specified with a negative argument: @kbd{M-- C-c C-z}.  The
whole subtree can be expanded, similarly to @kbd{C-c C-s} (@kbd{M-x
show-subtree}), by specifying a zero argument: @kbd{M-0 C-c C-z}.

  While you're zoomed in, you can still use Outline mode's exposure and
hiding functions without disturbing Foldout.  Also, since the buffer is
narrowed, ``global'' editing actions will only affect text under the
zoomed-in heading.  This is useful for restricting changes to a
particular chapter or section of your document.

@kindex C-c C-x
@findex foldout-exit-fold
  To unzoom (exit) a fold, use @kbd{C-c C-x} (@kbd{M-x foldout-exit-fold}).
This hides all the text and subheadings under the top-level heading and
returns you to the previous view of the buffer.  Specifying a numeric
argument exits that many levels of folds.  Specifying a zero argument exits all
folds.

  To cancel the narrowing of a fold without hiding the text and
subheadings, specify a negative argument.  For example, @kbd{M--2 C-c
C-x} exits two folds and leaves the text and subheadings exposed.

  Foldout mode also provides mouse commands for entering and exiting
folds, and for showing and hiding text:

@table @asis
@item @kbd{C-M-Mouse-1} zooms in on the heading clicked on
@itemize @asis
@item
single click: expose body.
@item
double click: expose subheadings.
@item
triple click: expose body and subheadings.
@item
quad click: expose entire subtree.
@end itemize
@item @kbd{C-M-Mouse-2} exposes text under the heading clicked on
@itemize @asis
@item
single click: expose body.
@item
double click: expose subheadings.
@item
triple click: expose body and subheadings.
@item
quad click: expose entire subtree.
@end itemize
@item @kbd{C-M-Mouse-3} hides text under the heading clicked on or exits fold
@itemize @asis
@item
single click: hide subtree.
@item
double click: exit fold and hide text.
@item
triple click: exit fold without hiding text.
@item
quad click: exit all folds and hide text.
@end itemize
@end table

@vindex foldout-mouse-modifiers
  You can specify different modifier keys (instead of
@kbd{Control-Meta-}) by setting @code{foldout-mouse-modifiers}; but if
you have already loaded the @file{foldout.el} library, you must reload
it in order for this to take effect.

  To use the Foldout package, you can type @kbd{M-x load-library
@key{RET} foldout @key{RET}}; or you can arrange for to do that
automatically by putting this in your @file{.emacs} file:

@example
(eval-after-load "outline" '(require 'foldout))
@end example

@node TeX Mode
@section @TeX{} Mode
@cindex @TeX{} mode
@cindex La@TeX{} mode
@cindex Sli@TeX{} mode
@cindex mode, @TeX{}
@cindex mode, La@TeX{}
@cindex mode, Sli@TeX{}
@findex tex-mode
@findex plain-tex-mode
@findex latex-mode
@findex slitex-mode

  @TeX{} is a powerful text formatter written by Donald Knuth; it is also
free, like GNU Emacs.  La@TeX{} is a simplified input format for @TeX{},
implemented by @TeX{} macros; it comes with @TeX{}.  Sli@TeX{} is a special
form of La@TeX{}.@footnote{Sli@TeX{} is obsoleted by the @samp{slides}
document class in recent La@TeX{} versions.}

  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.

@vindex tex-default-mode
  @TeX{} mode has three variants, Plain @TeX{} mode, La@TeX{} mode, and
Sli@TeX{} mode (these three distinct major modes differ only slightly).
They are designed for editing the three different formats.  The command
@kbd{M-x tex-mode} looks at the contents of the buffer to determine
whether the contents appear to be either La@TeX{} input or Sli@TeX{}
input; if so, it selects the appropriate mode.  If the file contents do
not appear to be La@TeX{} or Sli@TeX{}, it selects Plain @TeX{} mode.
If the contents are insufficient to determine this, the variable
@code{tex-default-mode} controls which mode is used.

  When @kbd{M-x tex-mode} does not guess right, you can use the commands
@kbd{M-x plain-tex-mode}, @kbd{M-x latex-mode}, and @kbd{M-x
slitex-mode} to select explicitly the particular variants of @TeX{}
mode.

@menu
* Editing: TeX Editing.   Special commands for editing in TeX mode.
* LaTeX: LaTeX Editing.   Additional commands for LaTeX input files.
* Printing: TeX Print.    Commands for printing part of a file with TeX.
* Misc: TeX Misc.         Customization of TeX mode, and related features.
@end menu

@node TeX Editing
@subsection @TeX{} Editing Commands

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

@table @kbd
@item "
Insert, according to context, either @samp{``} or @samp{"} or
@samp{''} (@code{tex-insert-quote}).
@item C-j
Insert a paragraph break (two newlines) and check the previous
paragraph for unbalanced braces or dollar signs
(@code{tex-terminate-paragraph}).
@item M-x tex-validate-region
Check each paragraph in the region for unbalanced braces or dollar signs.
@item C-c @{
Insert @samp{@{@}} and position point between them (@code{tex-insert-braces}).
@item C-c @}
Move forward past the next unmatched close brace (@code{up-list}).
@end table

@findex tex-insert-quote
@kindex " @r{(@TeX{} mode)}
  In @TeX{}, the character @samp{"} is not normally used; we use
@samp{``} to start a quotation and @samp{''} to end one.  To make
editing easier under this formatting convention, @TeX{} mode overrides
the normal meaning of the key @kbd{"} with a command that inserts a pair
of single-quotes or backquotes (@code{tex-insert-quote}).  To be
precise, this command inserts @samp{``} after whitespace or an open
brace, @samp{"} after a backslash, and @samp{''} after any other
character.

  If you need the character @samp{"} itself in unusual contexts, use
@kbd{C-q} to insert it.  Also, @kbd{"} with a numeric argument always
inserts that number of @samp{"} characters.  You can turn off the
feature of @kbd{"} expansion by eliminating that binding in the local
map (@pxref{Key Bindings}).

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

@findex tex-insert-braces
@kindex C-c @{ @r{(@TeX{} mode)}
@findex up-list
@kindex C-c @} @r{(@TeX{} mode)}
  @TeX{} uses braces as delimiters that must match.  Some users prefer
to keep braces balanced at all times, rather than inserting them
singly.  Use @kbd{C-c @{} (@code{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 @kbd{C-c @}}
(@code{up-list}) to move forward past the close brace.

@findex tex-validate-region
@findex tex-terminate-paragraph
@kindex C-j @r{(@TeX{} mode)}
  There are two commands for checking the matching of braces.  @kbd{C-j}
(@code{tex-terminate-paragraph}) checks the paragraph before point, and
inserts two newlines to start a new paragraph.  It outputs a message in
the echo area if any mismatch is found.  @kbd{M-x tex-validate-region}
checks a region, paragraph by paragraph.  The errors are listed in the
@samp{*Occur*} buffer, and you can use @kbd{C-c C-c} or @kbd{Mouse-2} in
that buffer to go to a particular mismatch.

  Note that Emacs commands count square brackets and parentheses in
@TeX{} mode, not just braces.  This is not strictly correct for the
purpose of checking @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.

@node LaTeX Editing
@subsection La@TeX{} Editing Commands

  La@TeX{} mode, and its variant, Sli@TeX{} mode, provide a few extra
features not applicable to plain @TeX{}.

@table @kbd
@item C-c C-o
Insert @samp{\begin} and @samp{\end} for La@TeX{} block and position
point on a line between them (@code{tex-latex-block}).
@item C-c C-e
Close the innermost La@TeX{} block not yet closed
(@code{tex-close-latex-block}).
@end table

@findex tex-latex-block
@kindex C-c C-o @r{(La@TeX{} mode)}
@vindex latex-block-names
  In La@TeX{} input, @samp{\begin} and @samp{\end} commands are used to
group blocks of text.  To insert a @samp{\begin} and a matching
@samp{\end} (on a new line following the @samp{\begin}), use @kbd{C-c
C-o} (@code{tex-latex-block}).  A blank line is inserted between the
two, and point is left there.  You can use completion when you enter the
block type; to specify additional block type names beyond the standard
list, set the variable @code{latex-block-names}.  For example, here's
how to add @samp{theorem}, @samp{corollary}, and @samp{proof}:

@example
(setq latex-block-names '("theorem" "corollary" "proof"))
@end example

@findex tex-close-latex-block
@kindex C-c C-e @r{(La@TeX{} mode)}
  In La@TeX{} input, @samp{\begin} and @samp{\end} commands must
balance.  You can use @kbd{C-c C-e} (@code{tex-close-latex-block}) to
insert automatically a matching @samp{\end} to match the last unmatched
@samp{\begin}.  It indents the @samp{\end} to match the corresponding
@samp{\begin}.  It inserts a newline after @samp{\end} if point is at
the beginning of a line.

@node TeX Print
@subsection @TeX{} Printing Commands

  You can invoke @TeX{} as an inferior of Emacs on either the entire
contents of the buffer or just a region at a time.  Running @TeX{} in
this way on just one chapter is a good way to see what your changes
look like without taking the time to format the entire file.

@table @kbd
@item C-c C-r
Invoke @TeX{} on the current region, together with the buffer's header
(@code{tex-region}).
@item C-c C-b
Invoke @TeX{} on the entire current buffer (@code{tex-buffer}).
@item C-c @key{TAB}
Invoke Bib@TeX{} on the current file (@code{tex-bibtex-file}).
@item C-c C-f
Invoke @TeX{} on the current file (@code{tex-file}).
@item C-c C-l
Recenter the window showing output from the inferior @TeX{} so that
the last line can be seen (@code{tex-recenter-output-buffer}).
@item C-c C-k
Kill the @TeX{} subprocess (@code{tex-kill-job}).
@item C-c C-p
Print the output from the last @kbd{C-c C-r}, @kbd{C-c C-b}, or @kbd{C-c
C-f} command (@code{tex-print}).
@item C-c C-v
Preview the output from the last @kbd{C-c C-r}, @kbd{C-c C-b}, or @kbd{C-c
C-f} command (@code{tex-view}).
@item C-c C-q
Show the printer queue (@code{tex-show-print-queue}).
@end table

@findex tex-buffer
@kindex C-c C-b @r{(@TeX{} mode)}
@findex tex-print
@kindex C-c C-p @r{(@TeX{} mode)}
@findex tex-view
@kindex C-c C-v @r{(@TeX{} mode)}
@findex tex-show-print-queue
@kindex C-c C-q @r{(@TeX{} mode)}
  You can pass the current buffer through an inferior @TeX{} by means of
@kbd{C-c C-b} (@code{tex-buffer}).  The formatted output appears in a
temporary file; to print it, type @kbd{C-c C-p} (@code{tex-print}).
Afterward, you can use @kbd{C-c C-q} (@code{tex-show-print-queue}) to
view the progress of your output towards being printed.  If your terminal
has the ability to display @TeX{} output files, you can preview the
output on the terminal with @kbd{C-c C-v} (@code{tex-view}).

@cindex @env{TEXINPUTS} environment variable
@vindex tex-directory
  You can specify the directory to use for running @TeX{} by setting the
variable @code{tex-directory}.  @code{"."} is the default value.  If
your environment variable @env{TEXINPUTS} contains relative directory
names, or if your files contains @samp{\input} commands with relative
file names, then @code{tex-directory} @emph{must} be @code{"."} or you
will get the wrong results.  Otherwise, it is safe to specify some other
directory, such as @code{"/tmp"}.

@vindex tex-run-command
@vindex latex-run-command
@vindex slitex-run-command
@vindex tex-dvi-print-command
@vindex tex-dvi-view-command
@vindex tex-show-queue-command
  If you want to specify which shell commands are used in the inferior @TeX{},
you can do so by setting the values of the variables @code{tex-run-command},
@code{latex-run-command}, @code{slitex-run-command},
@code{tex-dvi-print-command}, @code{tex-dvi-view-command}, and
@code{tex-show-queue-command}.  You @emph{must} set the value of
@code{tex-dvi-view-command} for your particular terminal; this variable
has no default value.  The other variables have default values that may
(or may not) be appropriate for your system.

  Normally, the file name given to these commands comes at the end of
the command string; for example, @samp{latex @var{filename}}.  In some
cases, however, the file name needs to be embedded in the command; an
example is when you need to provide the file name as an argument to one
command whose output is piped to another.  You can specify where to put
the file name with @samp{*} in the command string.  For example,

@example
(setq tex-dvi-print-command "dvips -f * | lpr")
@end example

@findex tex-kill-job
@kindex C-c C-k @r{(@TeX{} mode)}
@findex tex-recenter-output-buffer
@kindex C-c C-l @r{(@TeX{} mode)}
  The terminal output from @TeX{}, including any error messages, appears
in a buffer called @samp{*tex-shell*}.  If @TeX{} gets an error, you can
switch to this buffer and feed it input (this works as in Shell mode;
@pxref{Interactive Shell}).  Without switching to this buffer you can
scroll it so that its last line is visible by typing @kbd{C-c
C-l}.

  Type @kbd{C-c C-k} (@code{tex-kill-job}) to kill the @TeX{} process if
you see that its output is no longer useful.  Using @kbd{C-c C-b} or
@kbd{C-c C-r} also kills any @TeX{} process still running.@refill

@findex tex-region
@kindex C-c C-r @r{(@TeX{} mode)}
  You can also pass an arbitrary region through an inferior @TeX{} by typing
@kbd{C-c C-r} (@code{tex-region}).  This is tricky, however, because most files
of @TeX{} input contain commands at the beginning to set parameters and
define macros, without which no later part of the file will format
correctly.  To solve this problem, @kbd{C-c C-r} allows you to designate a
part of the file as containing essential commands; it is included before
the specified region as part of the input to @TeX{}.  The designated part
of the file is called the @dfn{header}.

@cindex header (@TeX{} mode)
  To indicate the bounds of the header in Plain @TeX{} mode, you insert two
special strings in the file.  Insert @samp{%**start of header} before the
header, and @samp{%**end of header} after it.  Each string must appear
entirely on one line, but there may be other text on the line before or
after.  The lines containing the two strings are included in the header.
If @samp{%**start of header} does not appear within the first 100 lines of
the buffer, @kbd{C-c C-r} assumes that there is no header.

  In La@TeX{} mode, the header begins with @samp{\documentclass} or
@samp{\documentstyle} and ends with @samp{\begin@{document@}}.  These
are commands that La@TeX{} requires you to use in any case, so nothing
special needs to be done to identify the header.

@findex tex-file
@kindex C-c C-f @r{(@TeX{} mode)}
  The commands (@code{tex-buffer}) and (@code{tex-region}) do all of their
work in a temporary directory, and do not have available any of the auxiliary
files needed by @TeX{} for cross-references; these commands are generally
not suitable for running the final copy in which all of the cross-references
need to be correct.

  When you want the auxiliary files for cross references, use @kbd{C-c
C-f} (@code{tex-file}) which runs @TeX{} on the current buffer's file,
in that file's directory.  Before running @TeX{}, it offers to save any
modified buffers.  Generally, you need to use (@code{tex-file}) twice to
get the cross-references right.

@vindex tex-start-options
  The value of the variable @code{tex-start-options} specifies
options for the @TeX{} run.

@vindex tex-start-commands
  The value of the variable @code{tex-start-commands} specifies @TeX{}
commands for starting @TeX{}.  The default value causes @TeX{} to run
in nonstop mode.  To run @TeX{} interactively, set the variable to
@code{""}.

@vindex tex-main-file
  Large @TeX{} documents are often split into several files---one main
file, plus subfiles.  Running @TeX{} on a subfile typically does not
work; you have to run it on the main file.  In order to make
@code{tex-file} useful when you are editing a subfile, you can set the
variable @code{tex-main-file} to the name of the main file.  Then
@code{tex-file} runs @TeX{} on that file.

  The most convenient way to use @code{tex-main-file} is to specify it
in a local variable list in each of the subfiles.  @xref{File
Variables}.

@findex tex-bibtex-file
@kindex C-c TAB @r{(@TeX{} mode)}
@vindex tex-bibtex-command
  For La@TeX{} files, you can use Bib@TeX{} to process the auxiliary
file for the current buffer's file.  Bib@TeX{} looks up bibliographic
citations in a data base and prepares the cited references for the
bibliography section.  The command @kbd{C-c TAB}
(@code{tex-bibtex-file}) runs the shell command
(@code{tex-bibtex-command}) to produce a @samp{.bbl} file for the
current buffer's file.  Generally, you need to do @kbd{C-c C-f}
(@code{tex-file}) once to generate the @samp{.aux} file, then do
@kbd{C-c TAB} (@code{tex-bibtex-file}), and then repeat @kbd{C-c C-f}
(@code{tex-file}) twice more to get the cross-references correct.

@node TeX Misc
@subsection @TeX{} Mode Miscellany

@vindex tex-shell-hook
@vindex tex-mode-hook
@vindex latex-mode-hook
@vindex slitex-mode-hook
@vindex plain-tex-mode-hook
  Entering any variant of @TeX{} mode runs the hooks
@code{text-mode-hook} and @code{tex-mode-hook}.  Then it runs either
@code{plain-tex-mode-hook}, @code{latex-mode-hook}, or
@code{slitex-mode-hook}, whichever is appropriate.  Starting the
@TeX{} shell runs the hook @code{tex-shell-hook}.  @xref{Hooks}.

@findex iso-iso2tex
@findex iso-tex2iso
@findex iso-iso2gtex
@findex iso-gtex2iso
@cindex Latin-1 @TeX{} encoding
@TeX{} encoding
  The commands @kbd{M-x iso-iso2tex}, @kbd{M-x iso-tex2iso}, @kbd{M-x
iso-iso2gtex} and @kbd{M-x iso-gtex2iso} can be used to convert
between Latin-1 encoded files and @TeX{}-encoded equivalents.
@ignore
@c Too cryptic to be useful, too cryptic for me to make it better -- rms.
  They
are included by default in the @code{format-alist} variable, so they
can be used with @kbd{M-x format-find-file}, for instance.
@end ignore

@ignore  @c Not worth documenting if it is only for Czech -- rms.
@findex tildify-buffer
@findex tildify-region
@cindex ties, @TeX{}, inserting
@cindex hard spaces, @TeX{}, inserting
  The commands @kbd{M-x tildify-buffer} and @kbd{M-x tildify-region}
insert @samp{~} (@dfn{tie}) characters where they are conventionally
required.  This is set up for Czech---customize the group
@samp{tildify} for other languages or for other sorts of markup.
@end ignore

@cindex Ref@TeX{} package
@cindex references, La@TeX{}
@cindex La@TeX{} references
  For managing all kinds of references for La@TeX{}, you can use
Ref@TeX{}.  @xref{Top, , RefTeX, reftex}.

@node HTML Mode
@section SGML, XML, and HTML Modes

  The major modes for SGML and HTML include indentation support and
commands to operate on tags.  This section describes the special
commands of these modes.  (HTML mode is a slightly customized variant
of SGML mode.)

@table @kbd
@item C-c C-n
@kindex C-c C-n @r{(SGML mode)}
@findex sgml-name-char
Interactively specify a special character and insert the SGML
@samp{&}-command for that character.

@item C-c C-t
@kindex C-c C-t @r{(SGML mode)}
@findex sgml-tag
Interactively specify a tag and its attributes (@code{sgml-tag}).
This command asks you for a tag name and for the attribute values,
then inserts both the opening tag and the closing tag, leaving point
between them.

With a prefix argument @var{n}, the command puts the tag around the
@var{n} words already present in the buffer after point.  With
@minus{}1 as argument, it puts the tag around the region.  (In
Transient Mark mode, it does this whenever a region is active.)

@item C-c C-a
@kindex C-c C-a @r{(SGML mode)}
@findex sgml-attributes
Interactively insert attribute values for the current tag
(@code{sgml-attributes}).

@item C-c C-f
@kindex C-c C-f @r{(SGML mode)}
@findex sgml-skip-tag-forward
Skip across a balanced tag group (which extends from an opening tag
through its corresponding closing tag) (@code{sgml-skip-tag-forward}).
A numeric argument acts as a repeat count.

@item C-c C-b
@kindex C-c C-b @r{(SGML mode)}
@findex sgml-skip-tag-backward
Skip backward across a balanced tag group (which extends from an
opening tag through its corresponding closing tag)
(@code{sgml-skip-tag-forward}).  A numeric argument acts as a repeat
count.

@item C-c C-d
@kindex C-c C-d @r{(SGML mode)}
@findex sgml-delete-tag
Delete the tag at or after point, and delete the matching tag too
(@code{sgml-delete-tag}).  If the tag at or after point is an opening
tag, delete the closing tag too; if it is a closing tag, delete the
opening tag too.

@item C-c ? @var{tag} @key{RET}
@kindex C-c ? @r{(SGML mode)}
@findex sgml-tag-help
Display a description of the meaning of tag @var{tag}
(@code{sgml-tag-help}).  If the argument @var{tag} is empty, describe
the tag at point.

@item C-c /
@kindex C-c / @r{(SGML mode)}
@findex sgml-close-tag
Insert a close tag for the innermost unterminated tag
(@code{sgml-close-tag}).  If called from within a tag or a comment,
close this element instead of inserting a close tag.

@item C-c 8
@kindex C-c 8 @r{(SGML mode)}
@findex sgml-name-8bit-mode
Toggle a minor mode in which Latin-1 characters insert the
corresponding SGML commands that stand for them, instead of the
characters themselves (@code{sgml-name-8bit-mode}).

@item C-c C-v
@kindex C-c C-v @r{(SGML mode)}
@findex sgml-validate
Run a shell command (which you must specify) to validate the current
buffer as SGML (@code{sgml-validate}).

@item C-x TAB
@kindex C-c TAB @r{(SGML mode)}
@findex sgml-tags-invisible
Toggle the visibility of existing tags in the buffer.  This can be
used as a cheap preview.
@end table

@vindex sgml-xml-mode
  SGML mode and HTML mode support XML also.  In XML, every opening tag
must have an explicit closing tag.  When @code{sgml-xml-mode} is
non-@code{nil}, SGML mode (and HTML mode) always insert explicit
closing tags.  When you visit a file, these modes determine from the
file contents whether it is XML or not, and set @code{sgml-xml-mode}
accordingly, so that they do the right thing for the file in either
case.

@node Nroff Mode
@section Nroff Mode

@cindex nroff
@findex nroff-mode
  Nroff mode is a mode like Text mode but modified to handle nroff commands
present in the text.  Invoke @kbd{M-x nroff-mode} to enter this mode.  It
differs from Text mode in only a few ways.  All nroff command lines are
considered paragraph separators, so that filling will never garble the
nroff commands.  Pages are separated by @samp{.bp} commands.  Comments
start with backslash-doublequote.  Also, three special commands are
provided that are not in Text mode:

@findex forward-text-line
@findex backward-text-line
@findex count-text-lines
@kindex M-n @r{(Nroff mode)}
@kindex M-p @r{(Nroff mode)}
@kindex M-? @r{(Nroff mode)}
@table @kbd
@item M-n
Move to the beginning of the next line that isn't an nroff command
(@code{forward-text-line}).  An argument is a repeat count.
@item M-p
Like @kbd{M-n} but move up (@code{backward-text-line}).
@item M-?
Displays in the echo area the number of text lines (lines that are not
nroff commands) in the region (@code{count-text-lines}).
@end table

@findex electric-nroff-mode
  The other feature of Nroff mode is that you can turn on Electric Nroff
mode.  This is a minor mode that you can turn on or off with @kbd{M-x
electric-nroff-mode} (@pxref{Minor Modes}).  When the mode is on, each
time you use @key{RET} to end a line that contains an nroff command that
opens a kind of grouping, the matching nroff command to close that
grouping is automatically inserted on the following line.  For example,
if you are at the beginning of a line and type @kbd{.@: ( b @key{RET}},
this inserts the matching command @samp{.)b} on a new line following
point.

  If you use Outline minor mode with Nroff mode (@pxref{Outline Mode}),
heading lines are lines of the form @samp{.H} followed by a number (the
header level).

@vindex nroff-mode-hook
  Entering Nroff mode runs the hook @code{text-mode-hook}, followed by
the hook @code{nroff-mode-hook} (@pxref{Hooks}).

@node Formatted Text
@section Editing Formatted Text

@cindex Enriched mode
@cindex mode, Enriched
@cindex formatted text
@cindex WYSIWYG
@cindex word processing
  @dfn{Enriched mode} is a minor mode for editing files that contain
formatted text in WYSIWYG fashion, as in a word processor.  Currently,
formatted text in Enriched mode can specify fonts, colors, underlining,
margins, and types of filling and justification.  In the future, we plan
to implement other formatting features as well.

  Enriched mode is a minor mode (@pxref{Minor Modes}).  It is
typically used in conjunction with Text mode (@pxref{Text Mode}), but
you can also use it with other major modes such as Outline mode and
Paragraph-Indent Text mode.

@cindex text/enriched MIME format
  Potentially, Emacs can store formatted text files in various file
formats.  Currently, only one format is implemented: @dfn{text/enriched}
format, which is defined by the MIME protocol.  @xref{Format
Conversion,, Format Conversion, elisp, the Emacs Lisp Reference Manual},
for details of how Emacs recognizes and converts file formats.

  The Emacs distribution contains a formatted text file that can serve as
an example.  Its name is @file{etc/enriched.doc}.  It contains samples
illustrating all the features described in this section.  It also
contains a list of ideas for future enhancements.

@menu
* Requesting Formatted Text::   Entering and exiting Enriched mode.
* Hard and Soft Newlines::      There are two different kinds of newlines.
* Editing Format Info::         How to edit text properties.
* Faces: Format Faces.          Bold, italic, underline, etc.
* Color: Format Colors.         Changing the color of text.
* Indent: Format Indentation.   Changing the left and right margins.
* Justification: Format Justification.
                                Centering, setting text flush with the
                                  left or right margin, etc.
* Other: Format Properties.     The "special" text properties submenu.
* Forcing Enriched Mode::       How to force use of Enriched mode.
@end menu

@node Requesting Formatted Text
@subsection Requesting to Edit Formatted Text

  Whenever you visit a file that Emacs saved in the text/enriched
format, Emacs automatically converts the formatting information in the
file into Emacs's own internal format (known as @dfn{text
properties}), and turns on Enriched mode.

@findex enriched-mode
  To create a new file of formatted text, first visit the nonexistent
file, then type @kbd{M-x enriched-mode} before you start inserting text.
This command turns on Enriched mode.  Do this before you begin inserting
text, to ensure that the text you insert is handled properly.

  More generally, the command @code{enriched-mode} turns Enriched mode
on if it was off, and off if it was on.  With a prefix argument, this
command turns Enriched mode on if the argument is positive, and turns
the mode off otherwise.

  When you save a buffer while Enriched mode is enabled in it, Emacs
automatically converts the text to text/enriched format while writing it
into the file.  When you visit the file again, Emacs will automatically
recognize the format, reconvert the text, and turn on Enriched mode
again.

@vindex enriched-fill-after-visiting
  Normally, after visiting a file in text/enriched format, Emacs refills
each paragraph to fit the specified right margin.  You can turn off this
refilling, to save time, by setting the variable
@code{enriched-fill-after-visiting} to @code{nil} or to @code{ask}.

  However, when visiting a file that was saved from Enriched mode, there
is no need for refilling, because Emacs saves the right margin settings
along with the text.

@vindex enriched-translations
  You can add annotations for saving additional text properties, which
Emacs normally does not save, by adding to @code{enriched-translations}.
Note that the text/enriched standard requires any non-standard
annotations to have names starting with @samp{x-}, as in
@samp{x-read-only}.  This ensures that they will not conflict with
standard annotations that may be added later.

  @xref{Text Properties,,, elisp, the Emacs Lisp Reference Manual},
for more information about text properties.

@node Hard and Soft Newlines
@subsection Hard and Soft Newlines
@cindex hard newline
@cindex soft newline
@cindex newlines, hard and soft

  In formatted text, Emacs distinguishes between two different kinds of
newlines, @dfn{hard} newlines and @dfn{soft} newlines.

  Hard newlines are used to separate paragraphs, or items in a list, or
anywhere that there should always be a line break regardless of the
margins.  The @key{RET} command (@code{newline}) and @kbd{C-o}
(@code{open-line}) insert hard newlines.

  Soft newlines are used to make text fit between the margins.  All the
fill commands, including Auto Fill, insert soft newlines---and they
delete only soft newlines.

  Although hard and soft newlines look the same, it is important to bear
the difference in mind.  Do not use @key{RET} to break lines in the
middle of filled paragraphs, or else you will get hard newlines that are
barriers to further filling.  Instead, let Auto Fill mode break lines,
so that if the text or the margins change, Emacs can refill the lines
properly.  @xref{Auto Fill}.

  On the other hand, in tables and lists, where the lines should always
remain as you type them, you can use @key{RET} to end lines.  For these
lines, you may also want to set the justification style to
@code{unfilled}.  @xref{Format Justification}.

@node Editing Format Info
@subsection Editing Format Information

  There are two ways to alter the formatting information for a formatted
text file: with keyboard commands, and with the mouse.

  The easiest way to add properties to your document is with the Text
Properties menu.  You can get to this menu in two ways: from the Edit
menu in the menu bar (use @kbd{@key{F10} e t} if you have no mouse),
or with @kbd{C-Mouse-2} (hold the @key{CTRL} key and press the middle
mouse button).  There are also keyboard commands described in the
following section.

  Most of the items in the Text Properties menu lead to other submenus.
These are described in the sections that follow.  Some items run
commands directly:

@table @code
@findex facemenu-remove-face-props
@item Remove Face Properties
Delete from the region all the text properties that the Text Properties
menu works with (@code{facemenu-remove-face-props}).

@findex facemenu-remove-all
@item Remove All
Delete @emph{all} text properties from the region
(@code{facemenu-remove-all}).

@findex describe-text-at
@cindex text properties of characters
@cindex overlays at character position
@cindex widgets at buffer position
@cindex buttons at buffer position
@item Describe Text
List all the text properties, widgets, buttons, and overlays of the
character following point (@code{describe-text-at}).

@item Display Faces
Display a list of all the defined faces (@code{list-faces-display}).

@item Display Colors
Display a list of all the defined colors (@code{list-colors-display}).
@end table

@node Format Faces
@subsection Faces in Formatted Text

  The Faces submenu lists various Emacs faces including @code{bold},
@code{italic}, and @code{underline}.  Selecting one of these adds the
chosen face to the region.  @xref{Faces}.  You can also specify a face
with these keyboard commands:

@table @kbd
@kindex M-g d @r{(Enriched mode)}
@findex facemenu-set-default
@item M-g d
Set the region, or the next inserted character, to the @code{default} face
(@code{facemenu-set-default}).
@kindex M-g b @r{(Enriched mode)}
@findex facemenu-set-bold
@item M-g b
Set the region, or the next inserted character, to the @code{bold} face
(@code{facemenu-set-bold}).
@kindex M-g i @r{(Enriched mode)}
@findex facemenu-set-italic
@item M-g i
Set the region, or the next inserted character, to the @code{italic} face
(@code{facemenu-set-italic}).
@kindex M-g l @r{(Enriched mode)}
@findex facemenu-set-bold-italic
@item M-g l
Set the region, or the next inserted character, to the @code{bold-italic} face
(@code{facemenu-set-bold-italic}).
@kindex M-g u @r{(Enriched mode)}
@findex facemenu-set-underline
@item M-g u
Set the region, or the next inserted character, to the @code{underline} face
(@code{facemenu-set-underline}).
@kindex M-g o @r{(Enriched mode)}
@findex facemenu-set-face
@item M-g o @var{face} @key{RET}
Set the region, or the next inserted character, to the face @var{face}
(@code{facemenu-set-face}).
@end table

  If you use these commands with a prefix argument---or, in Transient Mark
mode, if the region is not active---then these commands specify a face
to use for your next self-inserting input.  @xref{Transient Mark}.  This
applies to both the keyboard commands and the menu commands.

  Enriched mode defines two additional faces: @code{excerpt} and
@code{fixed}.  These correspond to codes used in the text/enriched file
format.

  The @code{excerpt} face is intended for quotations.  This face is the
same as @code{italic} unless you customize it (@pxref{Face Customization}).

  The @code{fixed} face means, ``Use a fixed-width font for this part
of the text.''  This makes a visible difference only if you have
specified a variable-width font in the default face; however, even if
the default font is fixed-width, applying the @code{fixed} face to a
part of the text will cause that part of the text to appear in a
fixed-width font, if the file is ever displayed with a variable-width
default font.  This applies to Emacs and to other systems that display
text/enriched format.  So if you specifically want a certain part of
the text to use a fixed-width font, you should specify the
@code{fixed} face for that part.

  The @code{fixed} face is normally set up to use a different font
from the default, even if the default face is also fixed-width.
Different systems have different fonts installed, so you may need to
customize this.  @xref{Face Customization}.

  If your terminal cannot display different faces, you will not be
able to see them, but you can still edit documents containing faces,
and even add faces and colors to documents.  The faces you specify
will be visible when the file is viewed on a terminal that can display
them.

@node Format Colors
@subsection Colors in Formatted Text

  You can specify foreground and background colors for portions of the
text.  There is a menu for specifying the foreground color and a menu
for specifying the background color.  Each color menu lists all the
colors that you have used in Enriched mode in the current Emacs session.

  If you specify a color with a prefix argument---or, in Transient Mark
mode, if the region is not active---then it applies to your next
self-inserting input.  @xref{Transient Mark}.  Otherwise, the command
applies to the region.

  Each color menu contains one additional item: @samp{Other}.  You can use
this item to specify a color that is not listed in the menu; it reads
the color name with the minibuffer.  To display list of available colors
and their names, use the @samp{Display Colors} menu item in the Text
Properties menu (@pxref{Editing Format Info}).

  Any color that you specify in this way, or that is mentioned in a
formatted text file that you read in, is added to both color menus for
the duration of the Emacs session.

@findex facemenu-set-foreground
@findex facemenu-set-background
  There are no key bindings for specifying colors, but you can do so
with the extended commands @kbd{M-x facemenu-set-foreground} and
@kbd{M-x facemenu-set-background}.  Both of these commands read the name
of the color with the minibuffer.

@node Format Indentation
@subsection Indentation in Formatted Text

  When editing formatted text, you can specify different amounts of
indentation for the right or left margin of an entire paragraph or a
part of a paragraph.  The margins you specify automatically affect the
Emacs fill commands (@pxref{Filling}) and line-breaking commands.

  The Indentation submenu provides a convenient interface for specifying
these properties.  The submenu contains four items:

@table @code
@kindex C-x TAB @r{(Enriched mode)}
@findex increase-left-margin
@item Indent More
Indent the region by 4 columns (@code{increase-left-margin}).  In
Enriched mode, this command is also available on @kbd{C-x @key{TAB}}; if
you supply a numeric argument, that says how many columns to add to the
margin (a negative argument reduces the number of columns).

@item Indent Less
Remove 4 columns of indentation from the region.

@item Indent Right More
Make the text narrower by indenting 4 columns at the right margin.

@item Indent Right Less
Remove 4 columns of indentation from the right margin.
@end table

  You can use these commands repeatedly to increase or decrease the
indentation.

  The most common way to use these commands is to change the indentation
of an entire paragraph.  However, that is not the only use.  You can
change the margins at any point; the new values take effect at the end
of the line (for right margins) or the beginning of the next line (for
left margins).

  This makes it possible to format paragraphs with @dfn{hanging indents},
which means that the first line is indented less than subsequent lines.
To set up a hanging indent, increase the indentation of the region
starting after the first word of the paragraph and running until the end
of the paragraph.

  Indenting the first line of a paragraph is easier.  Set the margin for
the whole paragraph where you want it to be for the body of the
paragraph, then indent the first line by inserting extra spaces or tabs.

  Sometimes, as a result of editing, the filling of a paragraph becomes
messed up---parts of the paragraph may extend past the left or right
margins.  When this happens, use @kbd{M-q} (@code{fill-paragraph}) to
refill the paragraph.

@vindex standard-indent
  The variable @code{standard-indent} specifies how many columns these
commands should add to or subtract from the indentation.  The default
value is 4.  The overall default right margin for Enriched mode is
controlled by the variable @code{fill-column}, as usual.

  The fill prefix, if any, works in addition to the specified paragraph
indentation: @kbd{C-x .} does not include the specified indentation's
whitespace in the new value for the fill prefix, and the fill commands
look for the fill prefix after the indentation on each line.  @xref{Fill
Prefix}.

@node Format Justification
@subsection Justification in Formatted Text

  When editing formatted text, you can specify various styles of
justification for a paragraph.  The style you specify automatically
affects the Emacs fill commands.

  The Justification submenu provides a convenient interface for specifying
the style.  The submenu contains five items:

@table @code
@item Flush Left
This is the most common style of justification (at least for English).
Lines are aligned at the left margin but left uneven at the right.

@item Flush Right
This aligns each line with the right margin.  Spaces and tabs are added
on the left, if necessary, to make lines line up on the right.

@item Full
This justifies the text, aligning both edges of each line.  Justified
text looks very nice in a printed book, where the spaces can all be
adjusted equally, but it does not look as nice with a fixed-width font
on the screen.  Perhaps a future version of Emacs will be able to adjust
the width of spaces in a line to achieve elegant justification.

@item Center
This centers every line between the current margins.

@item None
This turns off filling entirely.  Each line will remain as you wrote it;
the fill and auto-fill functions will have no effect on text which has
this setting.  You can, however, still indent the left margin.  In
unfilled regions, all newlines are treated as hard newlines (@pxref{Hard
and Soft Newlines}) .
@end table

  In Enriched mode, you can also specify justification from the keyboard
using the @kbd{M-j} prefix character:

@table @kbd
@kindex M-j l @r{(Enriched mode)}
@findex set-justification-left
@item M-j l
Make the region left-filled (@code{set-justification-left}).
@kindex M-j r @r{(Enriched mode)}
@findex set-justification-right
@item M-j r
Make the region right-filled (@code{set-justification-right}).
@kindex M-j f @r{(Enriched mode)}
@findex set-justification-full
@item M-j f
Make the region fully-justified (@code{set-justification-full}).
@kindex M-j c @r{(Enriched mode)}
@kindex M-S @r{(Enriched mode)}
@findex set-justification-center
@item M-j c
@itemx M-S
Make the region centered (@code{set-justification-center}).
@kindex M-j u @r{(Enriched mode)}
@findex set-justification-none
@item M-j u
Make the region unfilled (@code{set-justification-none}).
@end table

  Justification styles apply to entire paragraphs.  All the
justification-changing commands operate on the paragraph containing
point, or, if the region is active, on all paragraphs which overlap the
region.

@vindex default-justification
  The default justification style is specified by the variable
@code{default-justification}.  Its value should be one of the symbols
@code{left}, @code{right}, @code{full}, @code{center}, or @code{none}.

@node Format Properties
@subsection Setting Other Text Properties

  The Other Properties menu lets you add or remove three other useful text
properties: @code{read-only}, @code{invisible} and @code{intangible}.
The @code{intangible} property disallows moving point within the text,
the @code{invisible} text property hides text from display, and the
@code{read-only} property disallows alteration of the text.

  Each of these special properties has a menu item to add it to the
region.  The last menu item, @samp{Remove Special}, removes all of these
special properties from the text in the region.

  Currently, the @code{invisible} and @code{intangible} properties are
@emph{not} saved in the text/enriched format.  The @code{read-only}
property is saved, but it is not a standard part of the text/enriched
format, so other editors may not respect it.

@node Forcing Enriched Mode
@subsection Forcing Enriched Mode

  Normally, Emacs knows when you are editing formatted text because it
recognizes the special annotations used in the file that you visited.
However, there are situations in which you must take special actions
to convert file contents or turn on Enriched mode:

@itemize @bullet
@item
When you visit a file that was created with some other editor, Emacs may
not recognize the file as being in the text/enriched format.  In this
case, when you visit the file you will see the formatting commands
rather than the formatted text.  Type @kbd{M-x format-decode-buffer} to
translate it.

@item
When you @emph{insert} a file into a buffer, rather than visiting it.
Emacs does the necessary conversions on the text which you insert, but
it does not enable Enriched mode.  If you wish to do that, type @kbd{M-x
enriched-mode}.
@end itemize

  The command @code{format-decode-buffer} translates text in various
formats into Emacs's internal format.  It asks you to specify the format
to translate from; however, normally you can type just @key{RET}, which
tells Emacs to guess the format.

@findex format-find-file
  If you wish to look at text/enriched file in its raw form, as a
sequence of characters rather than as formatted text, use the @kbd{M-x
find-file-literally} command.  This visits a file, like
@code{find-file}, but does not do format conversion.  It also inhibits
character code conversion (@pxref{Coding Systems}) and automatic
uncompression (@pxref{Compressed Files}).  To disable format conversion
but allow character code conversion and/or automatic uncompression if
appropriate, use @code{format-find-file} with suitable arguments.