[Emacs-diffs] Changes to text.texi

[Glenn Morris]

CVSROOT:        /sources/emacs
Module name:    emacs
Changes by:     Glenn Morris <gm>       07/09/06 04:23:36

Index: text.texi
===================================================================
RCS file: text.texi
diff -N text.texi
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ text.texi   6 Sep 2007 04:23:36 -0000       1.1
@@ -0,0 +1,4303 @@
address@hidden -*-texinfo-*-
address@hidden This is part of the GNU Emacs Lisp Reference Manual.
address@hidden Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 
2000, 2001,
address@hidden   2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, 
Inc.
address@hidden See the file elisp.texi for copying conditions.
address@hidden ../info/text
address@hidden Text, Non-ASCII Characters, Markers, Top
address@hidden Text
address@hidden text
+
+  This chapter describes the functions that deal with the text in a
+buffer.  Most examine, insert, or delete text in the current buffer,
+often operating at point or on text adjacent to point.  Many are
+interactive.  All the functions that change the text provide for undoing
+the changes (@pxref{Undo}).
+
+  Many text-related functions operate on a region of text defined by two
+buffer positions passed in arguments named @var{start} and @var{end}.
+These arguments should be either markers (@pxref{Markers}) or numeric
+character positions (@pxref{Positions}).  The order of these arguments
+does not matter; it is all right for @var{start} to be the end of the
+region and @var{end} the beginning.  For example, @code{(delete-region 1
+10)} and @code{(delete-region 10 1)} are equivalent.  An
address@hidden error is signaled if either @var{start} or
address@hidden is outside the accessible portion of the buffer.  In an
+interactive call, point and the mark are used for these arguments.
+
address@hidden buffer contents
+  Throughout this chapter, ``text'' refers to the characters in the
+buffer, together with their properties (when relevant).  Keep in mind
+that point is always between two characters, and the cursor appears on
+the character after point.
+
address@hidden
+* Near Point::       Examining text in the vicinity of point.
+* Buffer Contents::  Examining text in a general fashion.
+* Comparing Text::   Comparing substrings of buffers.
+* Insertion::        Adding new text to a buffer.
+* Commands for Insertion::  User-level commands to insert text.
+* Deletion::         Removing text from a buffer.
+* User-Level Deletion::     User-level commands to delete text.
+* The Kill Ring::    Where removed text sometimes is saved for later use.
+* Undo::             Undoing changes to the text of a buffer.
+* Maintaining Undo:: How to enable and disable undo information.
+                       How to control how much information is kept.
+* Filling::          Functions for explicit filling.
+* Margins::          How to specify margins for filling commands.
+* Adaptive Fill::    Adaptive Fill mode chooses a fill prefix from context.
+* Auto Filling::     How auto-fill mode is implemented to break lines.
+* Sorting::          Functions for sorting parts of the buffer.
+* Columns::          Computing horizontal positions, and using them.
+* Indentation::      Functions to insert or adjust indentation.
+* Case Changes::     Case conversion of parts of the buffer.
+* Text Properties::  Assigning Lisp property lists to text characters.
+* Substitution::     Replacing a given character wherever it appears.
+* Transposition::    Swapping two portions of a buffer.
+* Registers::        How registers are implemented.  Accessing the text or
+                       position stored in a register.
+* Base 64::          Conversion to or from base 64 encoding.
+* MD5 Checksum::     Compute the MD5 "message digest"/"checksum".
+* Atomic Changes::   Installing several buffer changes "atomically".
+* Change Hooks::     Supplying functions to be run when text is changed.
address@hidden menu
+
address@hidden Near Point
address@hidden Examining Text Near Point
address@hidden text near point
+
+  Many functions are provided to look at the characters around point.
+Several simple functions are described here.  See also @code{looking-at}
+in @ref{Regexp Search}.
+
+In the following four functions, ``beginning'' or ``end'' of buffer
+refers to the beginning or end of the accessible portion.
+
address@hidden char-after &optional position
+This function returns the character in the current buffer at (i.e.,
+immediately after) position @var{position}.  If @var{position} is out of
+range for this purpose, either before the beginning of the buffer, or at
+or beyond the end, then the value is @code{nil}.  The default for
address@hidden is point.
+
+In the following example, assume that the first character in the
+buffer is @samp{@@}:
+
address@hidden
address@hidden
+(char-to-string (char-after 1))
+     @result{} "@@"
address@hidden group
address@hidden example
address@hidden defun
+
address@hidden char-before &optional position
+This function returns the character in the current buffer immediately
+before position @var{position}.  If @var{position} is out of range for
+this purpose, either at or before the beginning of the buffer, or beyond
+the end, then the value is @code{nil}.  The default for
address@hidden is point.
address@hidden defun
+
address@hidden following-char
+This function returns the character following point in the current
+buffer.  This is similar to @code{(char-after (point))}.  However, if
+point is at the end of the buffer, then @code{following-char} returns 0.
+
+Remember that point is always between characters, and the cursor
+normally appears over the character following point.  Therefore, the
+character returned by @code{following-char} is the character the
+cursor is over.
+
+In this example, point is between the @samp{a} and the @samp{c}.
+
address@hidden
address@hidden
+---------- Buffer: foo ----------
+Gentlemen may cry address@hidden Peace!,''
+but there is no peace.
+---------- Buffer: foo ----------
address@hidden group
+
address@hidden
+(char-to-string (preceding-char))
+     @result{} "a"
+(char-to-string (following-char))
+     @result{} "c"
address@hidden group
address@hidden example
address@hidden defun
+
address@hidden preceding-char
+This function returns the character preceding point in the current
+buffer.  See above, under @code{following-char}, for an example.  If
+point is at the beginning of the buffer, @code{preceding-char} returns
+0.
address@hidden defun
+
address@hidden bobp
+This function returns @code{t} if point is at the beginning of the
+buffer.  If narrowing is in effect, this means the beginning of the
+accessible portion of the text.  See also @code{point-min} in
address@hidden
address@hidden defun
+
address@hidden eobp
+This function returns @code{t} if point is at the end of the buffer.
+If narrowing is in effect, this means the end of accessible portion of
+the text.  See also @code{point-max} in @xref{Point}.
address@hidden defun
+
address@hidden bolp
+This function returns @code{t} if point is at the beginning of a line.
address@hidden Lines}.  The beginning of the buffer (or of its accessible
+portion) always counts as the beginning of a line.
address@hidden defun
+
address@hidden eolp
+This function returns @code{t} if point is at the end of a line.  The
+end of the buffer (or of its accessible portion) is always considered
+the end of a line.
address@hidden defun
+
address@hidden Buffer Contents
address@hidden Examining Buffer Contents
+
+  This section describes functions that allow a Lisp program to
+convert any portion of the text in the buffer into a string.
+
address@hidden buffer-substring start end
+This function returns a string containing a copy of the text of the
+region defined by positions @var{start} and @var{end} in the current
+buffer.  If the arguments are not positions in the accessible portion of
+the buffer, @code{buffer-substring} signals an @code{args-out-of-range}
+error.
+
+It is not necessary for @var{start} to be less than @var{end}; the
+arguments can be given in either order.  But most often the smaller
+argument is written first.
+
+Here's an example which assumes Font-Lock mode is not enabled:
+
address@hidden
address@hidden
+---------- Buffer: foo ----------
+This is the contents of buffer foo
+
+---------- Buffer: foo ----------
address@hidden group
+
address@hidden
+(buffer-substring 1 10)
+     @result{} "This is t"
address@hidden group
address@hidden
+(buffer-substring (point-max) 10)
+     @result{} "he contents of buffer foo\n"
address@hidden group
address@hidden example
+
+If the text being copied has any text properties, these are copied into
+the string along with the characters they belong to.  @xref{Text
+Properties}.  However, overlays (@pxref{Overlays}) in the buffer and
+their properties are ignored, not copied.
+
+For example, if Font-Lock mode is enabled, you might get results like
+these:
+
address@hidden
address@hidden
+(buffer-substring 1 10)
+     @result{} #("This is t" 0 1 (fontified t) 1 9 (fontified t))
address@hidden group
address@hidden example
address@hidden defun
+
address@hidden buffer-substring-no-properties start end
+This is like @code{buffer-substring}, except that it does not copy text
+properties, just the characters themselves.  @xref{Text Properties}.
address@hidden defun
+
address@hidden filter-buffer-substring start end &optional delete noprops
+This function passes the buffer text between @var{start} and @var{end}
+through the filter functions specified by the variable
address@hidden, and returns the value from the last
+filter function.  If @code{buffer-substring-filters} is @code{nil},
+the value is the unaltered text from the buffer, what
address@hidden would return.
+
+If @var{delete} is address@hidden, this function deletes the text
+between @var{start} and @var{end} after copying it, like
address@hidden
+
+If @var{noprops} is address@hidden, the final string returned does not
+include text properties, while the string passed through the filters
+still includes text properties from the buffer text.
+
+Lisp code should use this function instead of @code{buffer-substring},
address@hidden,
+or @code{delete-and-extract-region} when copying into user-accessible
+data structures such as the kill-ring, X clipboard, and registers.
+Major and minor modes can add functions to
address@hidden to alter such text as it is copied out
+of the buffer.
address@hidden defun
+
address@hidden buffer-substring-filters
+This variable should be a list of functions that accept a single
+argument, a string, and return a string.
address@hidden passes the buffer substring to the
+first function in this list, and the return value of each function is
+passed to the next function.  The return value of the last function is
+used as the return value of @code{filter-buffer-substring}.
+
+As a special convention, point is set to the start of the buffer text
+being operated on (i.e., the @var{start} argument for
address@hidden) before these functions are called.
+
+If this variable is @code{nil}, no filtering is performed.
address@hidden defvar
+
address@hidden buffer-string
+This function returns the contents of the entire accessible portion of
+the current buffer as a string.  It is equivalent to
+
address@hidden
+(buffer-substring (point-min) (point-max))
address@hidden example
+
address@hidden
address@hidden
+---------- Buffer: foo ----------
+This is the contents of buffer foo
+
+---------- Buffer: foo ----------
+
+(buffer-string)
+     @result{} "This is the contents of buffer foo\n"
address@hidden group
address@hidden example
address@hidden defun
+
address@hidden current-word &optional strict really-word
+This function returns the symbol (or word) at or near point, as a string.
+The return value includes no text properties.
+
+If the optional argument @var{really-word} is address@hidden, it finds a
+word; otherwise, it finds a symbol (which includes both word
+characters and symbol constituent characters).
+
+If the optional argument @var{strict} is address@hidden, then point
+must be in or next to the symbol or word---if no symbol or word is
+there, the function returns @code{nil}.  Otherwise, a nearby symbol or
+word on the same line is acceptable.
address@hidden defun
+
address@hidden thing-at-point thing
+Return the @var{thing} around or next to point, as a string.
+
+The argument @var{thing} is a symbol which specifies a kind of syntactic
+entity.  Possibilities include @code{symbol}, @code{list}, @code{sexp},
address@hidden, @code{filename}, @code{url}, @code{word}, @code{sentence},
address@hidden, @code{line}, @code{page}, and others.
+
address@hidden
+---------- Buffer: foo ----------
+Gentlemen may cry address@hidden Peace!,''
+but there is no peace.
+---------- Buffer: foo ----------
+
+(thing-at-point 'word)
+     @result{} "Peace"
+(thing-at-point 'line)
+     @result{} "Gentlemen may cry ``Peace! Peace!,''\n"
+(thing-at-point 'whitespace)
+     @result{} nil
address@hidden example
address@hidden defun
+
address@hidden Comparing Text
address@hidden Comparing Text
address@hidden comparing buffer text
+
+  This function lets you compare portions of the text in a buffer, without
+copying them into strings first.
+
address@hidden compare-buffer-substrings buffer1 start1 end1 buffer2 start2 end2
+This function lets you compare two substrings of the same buffer or two
+different buffers.  The first three arguments specify one substring,
+giving a buffer (or a buffer name) and two positions within the
+buffer.  The last three arguments specify the other substring in the
+same way.  You can use @code{nil} for @var{buffer1}, @var{buffer2}, or
+both to stand for the current buffer.
+
+The value is negative if the first substring is less, positive if the
+first is greater, and zero if they are equal.  The absolute value of
+the result is one plus the index of the first differing characters
+within the substrings.
+
+This function ignores case when comparing characters
+if @code{case-fold-search} is address@hidden  It always ignores
+text properties.
+
+Suppose the current buffer contains the text @samp{foobarbar
+haha!rara!}; then in this example the two substrings are @samp{rbar }
+and @samp{rara!}.  The value is 2 because the first substring is greater
+at the second character.
+
address@hidden
+(compare-buffer-substrings nil 6 11 nil 16 21)
+     @result{} 2
address@hidden example
address@hidden defun
+
address@hidden Insertion
address@hidden Inserting Text
address@hidden insertion of text
address@hidden text insertion
+
address@hidden insertion before point
address@hidden before point, insertion
+  @dfn{Insertion} means adding new text to a buffer.  The inserted text
+goes at point---between the character before point and the character
+after point.  Some insertion functions leave point before the inserted
+text, while other functions leave it after.  We call the former
+insertion @dfn{after point} and the latter insertion @dfn{before point}.
+
+  Insertion relocates markers that point at positions after the
+insertion point, so that they stay with the surrounding text
+(@pxref{Markers}).  When a marker points at the place of insertion,
+insertion may or may not relocate the marker, depending on the marker's
+insertion type (@pxref{Marker Insertion Types}).  Certain special
+functions such as @code{insert-before-markers} relocate all such markers
+to point after the inserted text, regardless of the markers' insertion
+type.
+
+  Insertion functions signal an error if the current buffer is
+read-only or if they insert within read-only text.
+
+  These functions copy text characters from strings and buffers along
+with their properties.  The inserted characters have exactly the same
+properties as the characters they were copied from.  By contrast,
+characters specified as separate arguments, not part of a string or
+buffer, inherit their text properties from the neighboring text.
+
+  The insertion functions convert text from unibyte to multibyte in
+order to insert in a multibyte buffer, and vice versa---if the text
+comes from a string or from a buffer.  However, they do not convert
+unibyte character codes 128 through 255 to multibyte characters, not
+even if the current buffer is a multibyte buffer.  @xref{Converting
+Representations}.
+
address@hidden insert &rest args
+This function inserts the strings and/or characters @var{args} into the
+current buffer, at point, moving point forward.  In other words, it
+inserts the text before point.  An error is signaled unless all
address@hidden are either strings or characters.  The value is @code{nil}.
address@hidden defun
+
address@hidden insert-before-markers &rest args
+This function inserts the strings and/or characters @var{args} into the
+current buffer, at point, moving point forward.  An error is signaled
+unless all @var{args} are either strings or characters.  The value is
address@hidden
+
+This function is unlike the other insertion functions in that it
+relocates markers initially pointing at the insertion point, to point
+after the inserted text.  If an overlay begins at the insertion point,
+the inserted text falls outside the overlay; if a nonempty overlay
+ends at the insertion point, the inserted text falls inside that
+overlay.
address@hidden defun
+
address@hidden insert-char character count &optional inherit
+This function inserts @var{count} instances of @var{character} into the
+current buffer before point.  The argument @var{count} should be an
+integer, and @var{character} must be a character.  The value is @code{nil}.
+
+This function does not convert unibyte character codes 128 through 255
+to multibyte characters, not even if the current buffer is a multibyte
+buffer.  @xref{Converting Representations}.
+
+If @var{inherit} is address@hidden, then the inserted characters inherit
+sticky text properties from the two characters before and after the
+insertion point.  @xref{Sticky Properties}.
address@hidden defun
+
address@hidden insert-buffer-substring from-buffer-or-name &optional start end
+This function inserts a portion of buffer @var{from-buffer-or-name}
+(which must already exist) into the current buffer before point.  The
+text inserted is the region between @var{start} and @var{end}.  (These
+arguments default to the beginning and end of the accessible portion of
+that buffer.)  This function returns @code{nil}.
+
+In this example, the form is executed with buffer @samp{bar} as the
+current buffer.  We assume that buffer @samp{bar} is initially empty.
+
address@hidden
address@hidden
+---------- Buffer: foo ----------
+We hold these truths to be self-evident, that all
+---------- Buffer: foo ----------
address@hidden group
+
address@hidden
+(insert-buffer-substring "foo" 1 20)
+     @result{} nil
+
+---------- Buffer: bar ----------
+We hold these address@hidden
+---------- Buffer: bar ----------
address@hidden group
address@hidden example
address@hidden defun
+
address@hidden insert-buffer-substring-no-properties from-buffer-or-name 
&optional start end
+This is like @code{insert-buffer-substring} except that it does not
+copy any text properties.
address@hidden defun
+
+  @xref{Sticky Properties}, for other insertion functions that inherit
+text properties from the nearby text in addition to inserting it.
+Whitespace inserted by indentation functions also inherits text
+properties.
+
address@hidden Commands for Insertion
address@hidden User-Level Insertion Commands
+
+  This section describes higher-level commands for inserting text,
+commands intended primarily for the user but useful also in Lisp
+programs.
+
address@hidden Command insert-buffer from-buffer-or-name
+This command inserts the entire accessible contents of
address@hidden (which must exist) into the current buffer
+after point.  It leaves the mark after the inserted text.  The value
+is @code{nil}.
address@hidden deffn
+
address@hidden Command self-insert-command count
address@hidden character insertion
address@hidden self-insertion
+This command inserts the last character typed; it does so @var{count}
+times, before point, and returns @code{nil}.  Most printing characters
+are bound to this command.  In routine use, @code{self-insert-command}
+is the most frequently called function in Emacs, but programs rarely use
+it except to install it on a keymap.
+
+In an interactive call, @var{count} is the numeric prefix argument.
+
+Self-insertion translates the input character through
address@hidden  @xref{Translation of Characters}.
+
+This command calls @code{auto-fill-function} whenever that is
address@hidden and the character inserted is in the table
address@hidden (@pxref{Auto Filling}).
+
address@hidden Cross refs reworded to prevent overfull hbox.  --rjc 15mar92
+This command performs abbrev expansion if Abbrev mode is enabled and
+the inserted character does not have word-constituent
+syntax. (@xref{Abbrevs}, and @ref{Syntax Class Table}.)  It is also
+responsible for calling @code{blink-paren-function} when the inserted
+character has close parenthesis syntax (@pxref{Blinking}).
+
+Do not try substituting your own definition of
address@hidden for the standard one.  The editor command
+loop handles this function specially.
address@hidden deffn
+
address@hidden Command newline &optional number-of-newlines
+This command inserts newlines into the current buffer before point.
+If @var{number-of-newlines} is supplied, that many newline characters
+are inserted.
+
address@hidden newline and Auto Fill mode
+This function calls @code{auto-fill-function} if the current column
+number is greater than the value of @code{fill-column} and
address@hidden is @code{nil}.  Typically what
address@hidden does is insert a newline; thus, the overall
+result in this case is to insert two newlines at different places: one
+at point, and another earlier in the line.  @code{newline} does not
+auto-fill if @var{number-of-newlines} is address@hidden
+
+This command indents to the left margin if that is not zero.
address@hidden
+
+The value returned is @code{nil}.  In an interactive call, @var{count}
+is the numeric prefix argument.
address@hidden deffn
+
address@hidden overwrite-mode
+This variable controls whether overwrite mode is in effect.  The value
+should be @code{overwrite-mode-textual}, @code{overwrite-mode-binary},
+or @code{nil}.  @code{overwrite-mode-textual} specifies textual
+overwrite mode (treats newlines and tabs specially), and
address@hidden specifies binary overwrite mode (treats
+newlines and tabs like any other characters).
address@hidden defvar
+
address@hidden Deletion
address@hidden Deleting Text
address@hidden text deletion
+
address@hidden deleting text vs killing
+  Deletion means removing part of the text in a buffer, without saving
+it in the kill ring (@pxref{The Kill Ring}).  Deleted text can't be
+yanked, but can be reinserted using the undo mechanism (@pxref{Undo}).
+Some deletion functions do save text in the kill ring in some special
+cases.
+
+  All of the deletion functions operate on the current buffer.
+
address@hidden Command erase-buffer
+This function deletes the entire text of the current buffer
+(@emph{not} just the accessible portion), leaving it
+empty.  If the buffer is read-only, it signals a @code{buffer-read-only}
+error; if some of the text in it is read-only, it signals a
address@hidden error.  Otherwise, it deletes the text without
+asking for any confirmation.  It returns @code{nil}.
+
+Normally, deleting a large amount of text from a buffer inhibits further
+auto-saving of that buffer ``because it has shrunk.''  However,
address@hidden does not do this, the idea being that the future
+text is not really related to the former text, and its size should not
+be compared with that of the former text.
address@hidden deffn
+
address@hidden Command delete-region start end
+This command deletes the text between positions @var{start} and
address@hidden in the current buffer, and returns @code{nil}.  If point was
+inside the deleted region, its value afterward is @var{start}.
+Otherwise, point relocates with the surrounding text, as markers do.
address@hidden deffn
+
address@hidden delete-and-extract-region start end
+This function deletes the text between positions @var{start} and
address@hidden in the current buffer, and returns a string containing the
+text just deleted.
+
+If point was inside the deleted region, its value afterward is
address@hidden  Otherwise, point relocates with the surrounding text, as
+markers do.
address@hidden defun
+
address@hidden Command delete-char count &optional killp
+This command deletes @var{count} characters directly after point, or
+before point if @var{count} is negative.  If @var{killp} is
address@hidden, then it saves the deleted characters in the kill ring.
+
+In an interactive call, @var{count} is the numeric prefix argument, and
address@hidden is the unprocessed prefix argument.  Therefore, if a prefix
+argument is supplied, the text is saved in the kill ring.  If no prefix
+argument is supplied, then one character is deleted, but not saved in
+the kill ring.
+
+The value returned is always @code{nil}.
address@hidden deffn
+
address@hidden Command delete-backward-char count &optional killp
address@hidden deleting previous char
+This command deletes @var{count} characters directly before point, or
+after point if @var{count} is negative.  If @var{killp} is
address@hidden, then it saves the deleted characters in the kill ring.
+
+In an interactive call, @var{count} is the numeric prefix argument, and
address@hidden is the unprocessed prefix argument.  Therefore, if a prefix
+argument is supplied, the text is saved in the kill ring.  If no prefix
+argument is supplied, then one character is deleted, but not saved in
+the kill ring.
+
+The value returned is always @code{nil}.
address@hidden deffn
+
address@hidden Command backward-delete-char-untabify count &optional killp
address@hidden tab deletion
+This command deletes @var{count} characters backward, changing tabs
+into spaces.  When the next character to be deleted is a tab, it is
+first replaced with the proper number of spaces to preserve alignment
+and then one of those spaces is deleted instead of the tab.  If
address@hidden is address@hidden, then the command saves the deleted
+characters in the kill ring.
+
+Conversion of tabs to spaces happens only if @var{count} is positive.
+If it is negative, exactly @address@hidden characters after point
+are deleted.
+
+In an interactive call, @var{count} is the numeric prefix argument, and
address@hidden is the unprocessed prefix argument.  Therefore, if a prefix
+argument is supplied, the text is saved in the kill ring.  If no prefix
+argument is supplied, then one character is deleted, but not saved in
+the kill ring.
+
+The value returned is always @code{nil}.
address@hidden deffn
+
address@hidden backward-delete-char-untabify-method
+This option specifies how @code{backward-delete-char-untabify} should
+deal with whitespace.  Possible values include @code{untabify}, the
+default, meaning convert a tab to many spaces and delete one;
address@hidden, meaning delete all tabs and spaces before point with
+one command; @code{all} meaning delete all tabs, spaces and newlines
+before point, and @code{nil}, meaning do nothing special for
+whitespace characters.
address@hidden defopt
+
address@hidden User-Level Deletion
address@hidden User-Level Deletion Commands
+
+  This section describes higher-level commands for deleting text,
+commands intended primarily for the user but useful also in Lisp
+programs.
+
address@hidden Command delete-horizontal-space &optional backward-only
address@hidden deleting whitespace
+This function deletes all spaces and tabs around point.  It returns
address@hidden
+
+If @var{backward-only} is address@hidden, the function deletes
+spaces and tabs before point, but not after point.
+
+In the following examples, we call @code{delete-horizontal-space} four
+times, once on each line, with point between the second and third
+characters on the line each time.
+
address@hidden
address@hidden
+---------- Buffer: foo ----------
+I @point{}thought
+I @point{}     thought
address@hidden thought
address@hidden thought
+---------- Buffer: foo ----------
address@hidden group
+
address@hidden
+(delete-horizontal-space)   ; @r{Four times.}
+     @result{} nil
+
+---------- Buffer: foo ----------
+Ithought
+Ithought
+Wethought
+You thought
+---------- Buffer: foo ----------
address@hidden group
address@hidden example
address@hidden deffn
+
address@hidden Command delete-indentation &optional join-following-p
+This function joins the line point is on to the previous line, deleting
+any whitespace at the join and in some cases replacing it with one
+space.  If @var{join-following-p} is address@hidden,
address@hidden joins this line to the following line
+instead.  The function returns @code{nil}.
+
+If there is a fill prefix, and the second of the lines being joined
+starts with the prefix, then @code{delete-indentation} deletes the
+fill prefix before joining the lines.  @xref{Margins}.
+
+In the example below, point is located on the line starting
address@hidden, and it makes no difference if there are trailing spaces
+in the preceding line.
+
address@hidden
address@hidden
+---------- Buffer: foo ----------
+When in the course of human
address@hidden    events, it becomes necessary
+---------- Buffer: foo ----------
address@hidden group
+
+(delete-indentation)
+     @result{} nil
+
address@hidden
+---------- Buffer: foo ----------
+When in the course of address@hidden events, it becomes necessary
+---------- Buffer: foo ----------
address@hidden group
address@hidden smallexample
+
+After the lines are joined, the function @code{fixup-whitespace} is
+responsible for deciding whether to leave a space at the junction.
address@hidden deffn
+
address@hidden Command fixup-whitespace
+This function replaces all the horizontal whitespace surrounding point
+with either one space or no space, according to the context.  It
+returns @code{nil}.
+
+At the beginning or end of a line, the appropriate amount of space is
+none.  Before a character with close parenthesis syntax, or after a
+character with open parenthesis or expression-prefix syntax, no space is
+also appropriate.  Otherwise, one space is appropriate.  @xref{Syntax
+Class Table}.
+
+In the example below, @code{fixup-whitespace} is called the first time
+with point before the word @samp{spaces} in the first line.  For the
+second invocation, point is directly after the @samp{(}.
+
address@hidden
address@hidden
+---------- Buffer: foo ----------
+This has too many     @point{}spaces
+This has too many spaces at the start of (@point{}   this list)
+---------- Buffer: foo ----------
address@hidden group
+
address@hidden
+(fixup-whitespace)
+     @result{} nil
+(fixup-whitespace)
+     @result{} nil
address@hidden group
+
address@hidden
+---------- Buffer: foo ----------
+This has too many spaces
+This has too many spaces at the start of (this list)
+---------- Buffer: foo ----------
address@hidden group
address@hidden smallexample
address@hidden deffn
+
address@hidden Command just-one-space &optional n
address@hidden !!SourceFile simple.el
+This command replaces any spaces and tabs around point with a single
+space, or @var{n} spaces if @var{n} is specified.  It returns
address@hidden
address@hidden deffn
+
address@hidden Command delete-blank-lines
+This function deletes blank lines surrounding point.  If point is on a
+blank line with one or more blank lines before or after it, then all but
+one of them are deleted.  If point is on an isolated blank line, then it
+is deleted.  If point is on a nonblank line, the command deletes all
+blank lines immediately following it.
+
+A blank line is defined as a line containing only tabs and spaces.
+
address@hidden returns @code{nil}.
address@hidden deffn
+
address@hidden The Kill Ring
address@hidden The Kill Ring
address@hidden kill ring
+
+  @dfn{Kill functions} delete text like the deletion functions, but save
+it so that the user can reinsert it by @dfn{yanking}.  Most of these
+functions have @samp{kill-} in their name.  By contrast, the functions
+whose names start with @samp{delete-} normally do not save text for
+yanking (though they can still be undone); these are ``deletion''
+functions.
+
+  Most of the kill commands are primarily for interactive use, and are
+not described here.  What we do describe are the functions provided for
+use in writing such commands.  You can use these functions to write
+commands for killing text.  When you need to delete text for internal
+purposes within a Lisp function, you should normally use deletion
+functions, so as not to disturb the kill ring contents.
address@hidden
+
+  Killed text is saved for later yanking in the @dfn{kill ring}.  This
+is a list that holds a number of recent kills, not just the last text
+kill.  We call this a ``ring'' because yanking treats it as having
+elements in a cyclic order.  The list is kept in the variable
address@hidden, and can be operated on with the usual functions for
+lists; there are also specialized functions, described in this section,
+that treat it as a ring.
+
+  Some people think this use of the word ``kill'' is unfortunate, since
+it refers to operations that specifically @emph{do not} destroy the
+entities ``killed.''  This is in sharp contrast to ordinary life, in
+which death is permanent and ``killed'' entities do not come back to
+life.  Therefore, other metaphors have been proposed.  For example, the
+term ``cut ring'' makes sense to people who, in pre-computer days, used
+scissors and paste to cut up and rearrange manuscripts.  However, it
+would be difficult to change the terminology now.
+
address@hidden
+* Kill Ring Concepts::     What text looks like in the kill ring.
+* Kill Functions::         Functions that kill text.
+* Yanking::                How yanking is done.
+* Yank Commands::          Commands that access the kill ring.
+* Low-Level Kill Ring::           Functions and variables for kill ring access.
+* Internals of Kill Ring:: Variables that hold kill ring data.
address@hidden menu
+
address@hidden Kill Ring Concepts
address@hidden  node-name,  next,  previous,  up
address@hidden Kill Ring Concepts
+
+  The kill ring records killed text as strings in a list, most recent
+first.  A short kill ring, for example, might look like this:
+
address@hidden
+("some text" "a different piece of text" "even older text")
address@hidden example
+
address@hidden
+When the list reaches @code{kill-ring-max} entries in length, adding a
+new entry automatically deletes the last entry.
+
+  When kill commands are interwoven with other commands, each kill
+command makes a new entry in the kill ring.  Multiple kill commands in
+succession build up a single kill ring entry, which would be yanked as a
+unit; the second and subsequent consecutive kill commands add text to
+the entry made by the first one.
+
+  For yanking, one entry in the kill ring is designated the ``front'' of
+the ring.  Some yank commands ``rotate'' the ring by designating a
+different element as the ``front.''  But this virtual rotation doesn't
+change the list itself---the most recent entry always comes first in the
+list.
+
address@hidden Kill Functions
address@hidden  node-name,  next,  previous,  up
address@hidden Functions for Killing
+
+  @code{kill-region} is the usual subroutine for killing text.  Any
+command that calls this function is a ``kill command'' (and should
+probably have @samp{kill} in its name).  @code{kill-region} puts the
+newly killed text in a new element at the beginning of the kill ring or
+adds it to the most recent element.  It determines automatically (using
address@hidden) whether the previous command was a kill command,
+and if so appends the killed text to the most recent entry.
+
address@hidden Command kill-region start end &optional yank-handler
+This function kills the text in the region defined by @var{start} and
address@hidden  The text is deleted but saved in the kill ring, along with
+its text properties.  The value is always @code{nil}.
+
+In an interactive call, @var{start} and @var{end} are point and
+the mark.
+
address@hidden Emacs 19 feature
+If the buffer or text is read-only, @code{kill-region} modifies the kill
+ring just the same, then signals an error without modifying the buffer.
+This is convenient because it lets the user use a series of kill
+commands to copy text from a read-only buffer into the kill ring.
+
+If @var{yank-handler} is address@hidden, this puts that value onto
+the string of killed text, as a @code{yank-handler} text property.
address@hidden  Note that if @var{yank-handler} is @code{nil}, any
address@hidden properties present on the killed text are copied
+onto the kill ring, like other text properties.
address@hidden deffn
+
address@hidden kill-read-only-ok
+If this option is address@hidden, @code{kill-region} does not signal an
+error if the buffer or text is read-only.  Instead, it simply returns,
+updating the kill ring but not changing the buffer.
address@hidden defopt
+
address@hidden Command copy-region-as-kill start end
+This command saves the region defined by @var{start} and @var{end} on
+the kill ring (including text properties), but does not delete the text
+from the buffer.  It returns @code{nil}.
+
+The command does not set @code{this-command} to @code{kill-region}, so a
+subsequent kill command does not append to the same kill ring entry.
+
+Don't call @code{copy-region-as-kill} in Lisp programs unless you aim to
+support Emacs 18.  For newer Emacs versions, it is better to use
address@hidden or @code{kill-append} instead.  @xref{Low-Level Kill
+Ring}.
address@hidden deffn
+
address@hidden Yanking
address@hidden Yanking
+
+  Yanking means inserting text from the kill ring, but it does
+not insert the text blindly.  Yank commands and some other commands
+use @code{insert-for-yank} to perform special processing on the
+text that they copy into the buffer.
+
address@hidden insert-for-yank string
+This function normally works like @code{insert} except that it doesn't
+insert the text properties in the @code{yank-excluded-properties}
+list.  However, if any part of @var{string} has a address@hidden
address@hidden text property, that property can do various
+special processing on that part of the text being inserted.
address@hidden defun
+
address@hidden insert-buffer-substring-as-yank buf &optional start end
+This function resembles @code{insert-buffer-substring} except that it
+doesn't insert the text properties in the
address@hidden list.
address@hidden defun
+
+  You can put a @code{yank-handler} text property on all or part of
+the text to control how it will be inserted if it is yanked.  The
address@hidden function looks for that property.  The property
+value must be a list of one to four elements, with the following
+format (where elements after the first may be omitted):
+
address@hidden
+(@var{function} @var{param} @var{noexclude} @var{undo})
address@hidden example
+
+  Here is what the elements do:
+
address@hidden @var
address@hidden function
+When @var{function} is present and address@hidden, it is called instead of
address@hidden to insert the string.  @var{function} takes one
+argument---the string to insert.
+
address@hidden param
+If @var{param} is present and address@hidden, it replaces @var{string}
+(or the part of @var{string} being processed) as the object passed to
address@hidden (or @code{insert}); for example, if @var{function} is
address@hidden, @var{param} should be a list of strings to
+insert as a rectangle.
+
address@hidden noexclude
+If @var{noexclude} is present and address@hidden, the normal removal of the
+yank-excluded-properties is not performed; instead @var{function} is
+responsible for removing those properties.  This may be necessary
+if @var{function} adjusts point before or after inserting the object.
+
address@hidden undo
+If @var{undo} is present and address@hidden, it is a function that will be
+called by @code{yank-pop} to undo the insertion of the current object.
+It is called with two arguments, the start and end of the current
+region.  @var{function} can set @code{yank-undo-function} to override
+the @var{undo} value.
address@hidden table
+
address@hidden Yank Commands
address@hidden  node-name,  next,  previous,  up
address@hidden Functions for Yanking
+
+  This section describes higher-level commands for yanking, which are
+intended primarily for the user but useful also in Lisp programs.
+Both @code{yank} and @code{yank-pop} honor the
address@hidden variable and @code{yank-handler} text
+property (@pxref{Yanking}).
+
address@hidden Command yank &optional arg
address@hidden inserting killed text
+This command inserts before point the text at the front of the
+kill ring.  It positions the mark at the beginning of that text, and
+point at the end.
+
+If @var{arg} is a address@hidden list (which occurs interactively when
+the user types @kbd{C-u} with no digits), then @code{yank} inserts the
+text as described above, but puts point before the yanked text and
+puts the mark after it.
+
+If @var{arg} is a number, then @code{yank} inserts the @var{arg}th
+most recently killed text---the @var{arg}th element of the kill ring
+list, counted cyclically from the front, which is considered the
+first element for this purpose.
+
address@hidden does not alter the contents of the kill ring, unless it
+used text provided by another program, in which case it pushes that text
+onto the kill ring.  However if @var{arg} is an integer different from
+one, it rotates the kill ring to place the yanked string at the front.
+
address@hidden returns @code{nil}.
address@hidden deffn
+
address@hidden Command yank-pop &optional arg
+This command replaces the just-yanked entry from the kill ring with a
+different entry from the kill ring.
+
+This is allowed only immediately after a @code{yank} or another
address@hidden  At such a time, the region contains text that was just
+inserted by yanking.  @code{yank-pop} deletes that text and inserts in
+its place a different piece of killed text.  It does not add the deleted
+text to the kill ring, since it is already in the kill ring somewhere.
+It does however rotate the kill ring to place the newly yanked string at
+the front.
+
+If @var{arg} is @code{nil}, then the replacement text is the previous
+element of the kill ring.  If @var{arg} is numeric, the replacement is
+the @var{arg}th previous kill.  If @var{arg} is negative, a more recent
+kill is the replacement.
+
+The sequence of kills in the kill ring wraps around, so that after the
+oldest one comes the newest one, and before the newest one goes the
+oldest.
+
+The return value is always @code{nil}.
address@hidden deffn
+
address@hidden yank-undo-function
+If this variable is address@hidden, the function @code{yank-pop} uses
+its value instead of @code{delete-region} to delete the text
+inserted by the previous @code{yank} or
address@hidden command.  The value must be a function of two
+arguments, the start and end of the current region.
+
+The function @code{insert-for-yank} automatically sets this variable
+according to the @var{undo} element of the @code{yank-handler}
+text property, if there is one.
address@hidden defvar
+
address@hidden Low-Level Kill Ring
address@hidden Low-Level Kill Ring
+
+  These functions and variables provide access to the kill ring at a
+lower level, but still convenient for use in Lisp programs, because they
+take care of interaction with window system selections
+(@pxref{Window System Selections}).
+
address@hidden current-kill n &optional do-not-move
+The function @code{current-kill} rotates the yanking pointer, which
+designates the ``front'' of the kill ring, by @var{n} places (from newer
+kills to older ones), and returns the text at that place in the ring.
+
+If the optional second argument @var{do-not-move} is address@hidden,
+then @code{current-kill} doesn't alter the yanking pointer; it just
+returns the @var{n}th kill, counting from the current yanking pointer.
+
+If @var{n} is zero, indicating a request for the latest kill,
address@hidden calls the value of
address@hidden (documented below) before
+consulting the kill ring.  If that value is a function and calling it
+returns a string, @code{current-kill} pushes that string onto the kill
+ring and returns it.  It also sets the yanking pointer to point to
+that new entry, regardless of the value of @var{do-not-move}.
+Otherwise, @code{current-kill} does not treat a zero value for @var{n}
+specially: it returns the entry pointed at by the yanking pointer and
+does not move the yanking pointer.
address@hidden defun
+
address@hidden kill-new string &optional replace yank-handler
+This function pushes the text @var{string} onto the kill ring and
+makes the yanking pointer point to it.  It discards the oldest entry
+if appropriate.  It also invokes the value of
address@hidden (see below).
+
+If @var{replace} is address@hidden, then @code{kill-new} replaces the
+first element of the kill ring with @var{string}, rather than pushing
address@hidden onto the kill ring.
+
+If @var{yank-handler} is address@hidden, this puts that value onto
+the string of killed text, as a @code{yank-handler} property.
address@hidden  Note that if @var{yank-handler} is @code{nil}, then
address@hidden copies any @code{yank-handler} properties present on
address@hidden onto the kill ring, as it does with other text properties.
address@hidden defun
+
address@hidden kill-append string before-p &optional yank-handler
+This function appends the text @var{string} to the first entry in the
+kill ring and makes the yanking pointer point to the combined entry.
+Normally @var{string} goes at the end of the entry, but if
address@hidden is address@hidden, it goes at the beginning.  This
+function also invokes the value of @code{interprogram-cut-function}
+(see below).  This handles @var{yank-handler} just like
address@hidden, except that if @var{yank-handler} is different from
+the @code{yank-handler} property of the first entry of the kill ring,
address@hidden pushes the concatenated string onto the kill ring,
+instead of replacing the original first entry with it.
address@hidden defun
+
address@hidden interprogram-paste-function
+This variable provides a way of transferring killed text from other
+programs, when you are using a window system.  Its value should be
address@hidden or a function of no arguments.
+
+If the value is a function, @code{current-kill} calls it to get the
+``most recent kill.''  If the function returns a address@hidden value,
+then that value is used as the ``most recent kill.''  If it returns
address@hidden, then the front of the kill ring is used.
+
+The normal use of this hook is to get the window system's primary
+selection as the most recent kill, even if the selection belongs to
+another application.  @xref{Window System Selections}.
address@hidden defvar
+
address@hidden interprogram-cut-function
+This variable provides a way of communicating killed text to other
+programs, when you are using a window system.  Its value should be
address@hidden or a function of one required and one optional argument.
+
+If the value is a function, @code{kill-new} and @code{kill-append} call
+it with the new first element of the kill ring as the first argument.
+The second, optional, argument has the same meaning as the @var{push}
+argument to @code{x-set-cut-buffer} (@pxref{Definition of
+x-set-cut-buffer}) and only affects the second and later cut buffers.
+
+The normal use of this hook is to set the window system's primary
+selection (and first cut buffer) from the newly killed text.
address@hidden System Selections}.
address@hidden defvar
+
address@hidden Internals of Kill Ring
address@hidden  node-name,  next,  previous,  up
address@hidden Internals of the Kill Ring
+
+  The variable @code{kill-ring} holds the kill ring contents, in the
+form of a list of strings.  The most recent kill is always at the front
+of the list.
+
+  The @code{kill-ring-yank-pointer} variable points to a link in the
+kill ring list, whose @sc{car} is the text to yank next.  We say it
+identifies the ``front'' of the ring.  Moving
address@hidden to a different link is called
address@hidden the kill ring}.  We call the kill ring a ``ring'' because
+the functions that move the yank pointer wrap around from the end of the
+list to the beginning, or vice-versa.  Rotation of the kill ring is
+virtual; it does not change the value of @code{kill-ring}.
+
+  Both @code{kill-ring} and @code{kill-ring-yank-pointer} are Lisp
+variables whose values are normally lists.  The word ``pointer'' in the
+name of the @code{kill-ring-yank-pointer} indicates that the variable's
+purpose is to identify one element of the list for use by the next yank
+command.
+
+  The value of @code{kill-ring-yank-pointer} is always @code{eq} to one
+of the links in the kill ring list.  The element it identifies is the
address@hidden of that link.  Kill commands, which change the kill ring, also
+set this variable to the value of @code{kill-ring}.  The effect is to
+rotate the ring so that the newly killed text is at the front.
+
+  Here is a diagram that shows the variable @code{kill-ring-yank-pointer}
+pointing to the second entry in the kill ring @code{("some text" "a
+different piece of text" "yet older text")}.
+
address@hidden
address@hidden
+kill-ring                  ---- kill-ring-yank-pointer
+  |                       |
+  |                       v
+  |     --- ---          --- ---      --- ---
+   --> |   |   |------> |   |   |--> |   |   |--> nil
+        --- ---          --- ---      --- ---
+         |                |            |
+         |                |            |
+         |                |             -->"yet older text"
+         |                |
+         |                 --> "a different piece of text"
+         |
+          --> "some text"
address@hidden group
address@hidden example
+
address@hidden
+This state of affairs might occur after @kbd{C-y} (@code{yank})
+immediately followed by @kbd{M-y} (@code{yank-pop}).
+
address@hidden kill-ring
+This variable holds the list of killed text sequences, most recently
+killed first.
address@hidden defvar
+
address@hidden kill-ring-yank-pointer
+This variable's value indicates which element of the kill ring is at the
+``front'' of the ring for yanking.  More precisely, the value is a tail
+of the value of @code{kill-ring}, and its @sc{car} is the kill string
+that @kbd{C-y} should yank.
address@hidden defvar
+
address@hidden kill-ring-max
+The value of this variable is the maximum length to which the kill
+ring can grow, before elements are thrown away at the end.  The default
+value for @code{kill-ring-max} is 60.
address@hidden defopt
+
address@hidden Undo
address@hidden  node-name,  next,  previous,  up
address@hidden Undo
address@hidden redo
+
+  Most buffers have an @dfn{undo list}, which records all changes made
+to the buffer's text so that they can be undone.  (The buffers that
+don't have one are usually special-purpose buffers for which Emacs
+assumes that undoing is not useful.  In particular, any buffer whose
+name begins with a space has its undo recording off by default;
+see @ref{Buffer Names}.)  All the primitives that modify the
+text in the buffer automatically add elements to the front of the undo
+list, which is in the variable @code{buffer-undo-list}.
+
address@hidden buffer-undo-list
+This buffer-local variable's value is the undo list of the current
+buffer. A value of @code{t} disables the recording of undo information.
address@hidden defvar
+
+Here are the kinds of elements an undo list can have:
+
address@hidden @code
address@hidden @var{position}
+This kind of element records a previous value of point; undoing this
+element moves point to @var{position}.  Ordinary cursor motion does not
+make any sort of undo record, but deletion operations use these entries
+to record where point was before the command.
+
address@hidden (@var{beg} . @var{end})
+This kind of element indicates how to delete text that was inserted.
+Upon insertion, the text occupied the range @address@hidden in the
+buffer.
+
address@hidden (@var{text} . @var{position})
+This kind of element indicates how to reinsert text that was deleted.
+The deleted text itself is the string @var{text}.  The place to
+reinsert it is @code{(abs @var{position})}.  If @var{position} is
+positive, point was at the beginning of the deleted text, otherwise it
+was at the end.
+
address@hidden (t @var{high} . @var{low})
+This kind of element indicates that an unmodified buffer became
+modified.  The elements @var{high} and @var{low} are two integers, each
+recording 16 bits of the visited file's modification time as of when it
+was previously visited or saved.  @code{primitive-undo} uses those
+values to determine whether to mark the buffer as unmodified once again;
+it does so only if the file's modification time matches those numbers.
+
address@hidden (nil @var{property} @var{value} @var{beg} . @var{end})
+This kind of element records a change in a text property.
+Here's how you might undo the change:
+
address@hidden
+(put-text-property @var{beg} @var{end} @var{property} @var{value})
address@hidden example
+
address@hidden (@var{marker} . @var{adjustment})
+This kind of element records the fact that the marker @var{marker} was
+relocated due to deletion of surrounding text, and that it moved
address@hidden character positions.  Undoing this element moves
address@hidden @minus{} @var{adjustment} characters.
+
address@hidden (apply @var{funname} . @var{args})
+This is an extensible undo item, which is undone by calling
address@hidden with arguments @var{args}.
+
address@hidden (apply @var{delta} @var{beg} @var{end} @var{funname} . 
@var{args})
+This is an extensible undo item, which records a change limited to the
+range @var{beg} to @var{end}, which increased the size of the buffer
+by @var{delta}.  It is undone by calling @var{funname} with arguments
address@hidden
+
+This kind of element enables undo limited to a region to determine
+whether the element pertains to that region.
+
address@hidden nil
+This element is a boundary.  The elements between two boundaries are
+called a @dfn{change group}; normally, each change group corresponds to
+one keyboard command, and undo commands normally undo an entire group as
+a unit.
address@hidden table
+
address@hidden undo-boundary
+This function places a boundary element in the undo list.  The undo
+command stops at such a boundary, and successive undo commands undo
+to earlier and earlier boundaries.  This function returns @code{nil}.
+
+The editor command loop automatically creates an undo boundary before
+each key sequence is executed.  Thus, each undo normally undoes the
+effects of one command.  Self-inserting input characters are an
+exception.  The command loop makes a boundary for the first such
+character; the next 19 consecutive self-inserting input characters do
+not make boundaries, and then the 20th does, and so on as long as
+self-inserting characters continue.
+
+All buffer modifications add a boundary whenever the previous undoable
+change was made in some other buffer.  This is to ensure that
+each command makes a boundary in each buffer where it makes changes.
+
+Calling this function explicitly is useful for splitting the effects of
+a command into more than one unit.  For example, @code{query-replace}
+calls @code{undo-boundary} after each replacement, so that the user can
+undo individual replacements one by one.
address@hidden defun
+
address@hidden undo-in-progress
+This variable is normally @code{nil}, but the undo commands bind it to
address@hidden  This is so that various kinds of change hooks can tell when
+they're being called for the sake of undoing.
address@hidden defvar
+
address@hidden primitive-undo count list
+This is the basic function for undoing elements of an undo list.
+It undoes the first @var{count} elements of @var{list}, returning
+the rest of @var{list}.
+
address@hidden adds elements to the buffer's undo list when it
+changes the buffer.  Undo commands avoid confusion by saving the undo
+list value at the beginning of a sequence of undo operations.  Then the
+undo operations use and update the saved value.  The new elements added
+by undoing are not part of this saved value, so they don't interfere with
+continuing to undo.
+
+This function does not bind @code{undo-in-progress}.
address@hidden defun
+
address@hidden Maintaining Undo
address@hidden Maintaining Undo Lists
+
+  This section describes how to enable and disable undo information for
+a given buffer.  It also explains how the undo list is truncated
+automatically so it doesn't get too big.
+
+  Recording of undo information in a newly created buffer is normally
+enabled to start with; but if the buffer name starts with a space, the
+undo recording is initially disabled.  You can explicitly enable or
+disable undo recording with the following two functions, or by setting
address@hidden yourself.
+
address@hidden Command buffer-enable-undo &optional buffer-or-name
+This command enables recording undo information for buffer
address@hidden, so that subsequent changes can be undone.  If no
+argument is supplied, then the current buffer is used.  This function
+does nothing if undo recording is already enabled in the buffer.  It
+returns @code{nil}.
+
+In an interactive call, @var{buffer-or-name} is the current buffer.
+You cannot specify any other buffer.
address@hidden deffn
+
address@hidden Command buffer-disable-undo &optional buffer-or-name
address@hidden disabling undo
+This function discards the undo list of @var{buffer-or-name}, and disables
+further recording of undo information.  As a result, it is no longer
+possible to undo either previous changes or any subsequent changes.  If
+the undo list of @var{buffer-or-name} is already disabled, this function
+has no effect.
+
+This function returns @code{nil}.
address@hidden deffn
+
+  As editing continues, undo lists get longer and longer.  To prevent
+them from using up all available memory space, garbage collection trims
+them back to size limits you can set.  (For this purpose, the ``size''
+of an undo list measures the cons cells that make up the list, plus the
+strings of deleted text.)  Three variables control the range of acceptable
+sizes: @code{undo-limit}, @code{undo-strong-limit} and
address@hidden  In these variables, size is counted as the
+number of bytes occupied, which includes both saved text and other
+data.
+
address@hidden undo-limit
+This is the soft limit for the acceptable size of an undo list.  The
+change group at which this size is exceeded is the last one kept.
address@hidden defopt
+
address@hidden undo-strong-limit
+This is the upper limit for the acceptable size of an undo list.  The
+change group at which this size is exceeded is discarded itself (along
+with all older change groups).  There is one exception: the very latest
+change group is only discarded if it exceeds @code{undo-outer-limit}.
address@hidden defopt
+
address@hidden undo-outer-limit
+If at garbage collection time the undo info for the current command
+exceeds this limit, Emacs discards the info and displays a warning.
+This is a last ditch limit to prevent memory overflow.
address@hidden defopt
+
address@hidden undo-ask-before-discard
+If this variable is address@hidden, when the undo info exceeds
address@hidden, Emacs asks in the echo area whether to
+discard the info.  The default value is @code{nil}, which means to
+discard it automatically.
+
+This option is mainly intended for debugging.  Garbage collection is
+inhibited while the question is asked, which means that Emacs might
+leak memory if the user waits too long before answering the question.
address@hidden defopt
+
address@hidden Filling
address@hidden  node-name,  next,  previous,  up
address@hidden Filling
address@hidden filling text
+
+  @dfn{Filling} means adjusting the lengths of lines (by moving the line
+breaks) so that they are nearly (but no greater than) a specified
+maximum width.  Additionally, lines can be @dfn{justified}, which means
+inserting spaces to make the left and/or right margins line up
+precisely.  The width is controlled by the variable @code{fill-column}.
+For ease of reading, lines should be no longer than 70 or so columns.
+
+  You can use Auto Fill mode (@pxref{Auto Filling}) to fill text
+automatically as you insert it, but changes to existing text may leave
+it improperly filled.  Then you must fill the text explicitly.
+
+  Most of the commands in this section return values that are not
+meaningful.  All the functions that do filling take note of the current
+left margin, current right margin, and current justification style
+(@pxref{Margins}).  If the current justification style is
address@hidden, the filling functions don't actually do anything.
+
+  Several of the filling functions have an argument @var{justify}.
+If it is address@hidden, that requests some kind of justification.  It
+can be @code{left}, @code{right}, @code{full}, or @code{center}, to
+request a specific style of justification.  If it is @code{t}, that
+means to use the current justification style for this part of the text
+(see @code{current-justification}, below).  Any other value is treated
+as @code{full}.
+
+  When you call the filling functions interactively, using a prefix
+argument implies the value @code{full} for @var{justify}.
+
address@hidden Command fill-paragraph justify
+This command fills the paragraph at or after point.  If
address@hidden is address@hidden, each line is justified as well.
+It uses the ordinary paragraph motion commands to find paragraph
+boundaries.  @xref{Paragraphs,,, emacs, The GNU Emacs Manual}.
address@hidden deffn
+
address@hidden Command fill-region start end &optional justify nosqueeze to-eop
+This command fills each of the paragraphs in the region from @var{start}
+to @var{end}.  It justifies as well if @var{justify} is
address@hidden
+
+If @var{nosqueeze} is address@hidden, that means to leave whitespace
+other than line breaks untouched.  If @var{to-eop} is address@hidden,
+that means to keep filling to the end of the paragraph---or the next hard
+newline, if @code{use-hard-newlines} is enabled (see below).
+
+The variable @code{paragraph-separate} controls how to distinguish
+paragraphs.  @xref{Standard Regexps}.
address@hidden deffn
+
address@hidden Command fill-individual-paragraphs start end &optional justify 
citation-regexp
+This command fills each paragraph in the region according to its
+individual fill prefix.  Thus, if the lines of a paragraph were indented
+with spaces, the filled paragraph will remain indented in the same
+fashion.
+
+The first two arguments, @var{start} and @var{end}, are the beginning
+and end of the region to be filled.  The third and fourth arguments,
address@hidden and @var{citation-regexp}, are optional.  If
address@hidden is address@hidden, the paragraphs are justified as
+well as filled.  If @var{citation-regexp} is address@hidden, it means the
+function is operating on a mail message and therefore should not fill
+the header lines.  If @var{citation-regexp} is a string, it is used as
+a regular expression; if it matches the beginning of a line, that line
+is treated as a citation marker.
+
+Ordinarily, @code{fill-individual-paragraphs} regards each change in
+indentation as starting a new paragraph.  If
address@hidden is address@hidden, then only
+separator lines separate paragraphs.  That mode can handle indented
+paragraphs with additional indentation on the first line.
address@hidden deffn
+
address@hidden fill-individual-varying-indent
+This variable alters the action of @code{fill-individual-paragraphs} as
+described above.
address@hidden defopt
+
address@hidden Command fill-region-as-paragraph start end &optional justify 
nosqueeze squeeze-after
+This command considers a region of text as a single paragraph and fills
+it.  If the region was made up of many paragraphs, the blank lines
+between paragraphs are removed.  This function justifies as well as
+filling when @var{justify} is address@hidden
+
+If @var{nosqueeze} is address@hidden, that means to leave whitespace
+other than line breaks untouched.  If @var{squeeze-after} is
address@hidden, it specifies a position in the region, and means don't
+canonicalize spaces before that position.
+
+In Adaptive Fill mode, this command calls @code{fill-context-prefix} to
+choose a fill prefix by default.  @xref{Adaptive Fill}.
address@hidden deffn
+
address@hidden Command justify-current-line &optional how eop nosqueeze
+This command inserts spaces between the words of the current line so
+that the line ends exactly at @code{fill-column}.  It returns
address@hidden
+
+The argument @var{how}, if address@hidden specifies explicitly the style
+of justification.  It can be @code{left}, @code{right}, @code{full},
address@hidden, or @code{none}.  If it is @code{t}, that means to do
+follow specified justification style (see @code{current-justification},
+below).  @code{nil} means to do full justification.
+
+If @var{eop} is address@hidden, that means do only left-justification
+if @code{current-justification} specifies full justification.  This is
+used for the last line of a paragraph; even if the paragraph as a
+whole is fully justified, the last line should not be.
+
+If @var{nosqueeze} is address@hidden, that means do not change interior
+whitespace.
address@hidden deffn
+
address@hidden default-justification
+This variable's value specifies the style of justification to use for
+text that doesn't specify a style with a text property.  The possible
+values are @code{left}, @code{right}, @code{full}, @code{center}, or
address@hidden  The default value is @code{left}.
address@hidden defopt
+
address@hidden current-justification
+This function returns the proper justification style to use for filling
+the text around point.
+
+This returns the value of the @code{justification} text property at
+point, or the variable @var{default-justification} if there is no such
+text property.  However, it returns @code{nil} rather than @code{none}
+to mean ``don't justify''.
address@hidden defun
+
address@hidden sentence-end-double-space
address@hidden of sentence-end-double-space}
+If this variable is address@hidden, a period followed by just one space
+does not count as the end of a sentence, and the filling functions
+avoid breaking the line at such a place.
address@hidden defopt
+
address@hidden sentence-end-without-period
+If this variable is address@hidden, a sentence can end without a
+period.  This is used for languages like Thai, where sentences end
+with a double space but without a period.
address@hidden defopt
+
address@hidden sentence-end-without-space
+If this variable is address@hidden, it should be a string of
+characters that can end a sentence without following spaces.
address@hidden defopt
+
address@hidden fill-paragraph-function
+This variable provides a way for major modes to override the filling of
+paragraphs.  If the value is address@hidden, @code{fill-paragraph} calls
+this function to do the work.  If the function returns a address@hidden
+value, @code{fill-paragraph} assumes the job is done, and immediately
+returns that value.
+
+The usual use of this feature is to fill comments in programming
+language modes.  If the function needs to fill a paragraph in the usual
+way, it can do so as follows:
+
address@hidden
+(let ((fill-paragraph-function nil))
+  (fill-paragraph arg))
address@hidden example
address@hidden defvar
+
address@hidden use-hard-newlines
+If this variable is address@hidden, the filling functions do not delete
+newlines that have the @code{hard} text property.  These ``hard
+newlines'' act as paragraph separators.
address@hidden defvar
+
address@hidden Margins
address@hidden Margins for Filling
+
address@hidden fill-prefix
+This buffer-local variable, if address@hidden, specifies a string of
+text that appears at the beginning of normal text lines and should be
+disregarded when filling them.  Any line that fails to start with the
+fill prefix is considered the start of a paragraph; so is any line
+that starts with the fill prefix followed by additional whitespace.
+Lines that start with the fill prefix but no additional whitespace are
+ordinary text lines that can be filled together.  The resulting filled
+lines also start with the fill prefix.
+
+The fill prefix follows the left margin whitespace, if any.
address@hidden defopt
+
address@hidden fill-column
+This buffer-local variable specifies the maximum width of filled lines.
+Its value should be an integer, which is a number of columns.  All the
+filling, justification, and centering commands are affected by this
+variable, including Auto Fill mode (@pxref{Auto Filling}).
+
+As a practical matter, if you are writing text for other people to
+read, you should set @code{fill-column} to no more than 70.  Otherwise
+the line will be too long for people to read comfortably, and this can
+make the text seem clumsy.
address@hidden defopt
+
address@hidden default-fill-column
+The value of this variable is the default value for @code{fill-column} in
+buffers that do not override it.  This is the same as
address@hidden(default-value 'fill-column)}.
+
+The default value for @code{default-fill-column} is 70.
address@hidden defvar
+
address@hidden Command set-left-margin from to margin
+This sets the @code{left-margin} property on the text from @var{from} to
address@hidden to the value @var{margin}.  If Auto Fill mode is enabled, this
+command also refills the region to fit the new margin.
address@hidden deffn
+
address@hidden Command set-right-margin from to margin
+This sets the @code{right-margin} property on the text from @var{from}
+to @var{to} to the value @var{margin}.  If Auto Fill mode is enabled,
+this command also refills the region to fit the new margin.
address@hidden deffn
+
address@hidden current-left-margin
+This function returns the proper left margin value to use for filling
+the text around point.  The value is the sum of the @code{left-margin}
+property of the character at the start of the current line (or zero if
+none), and the value of the variable @code{left-margin}.
address@hidden defun
+
address@hidden current-fill-column
+This function returns the proper fill column value to use for filling
+the text around point.  The value is the value of the @code{fill-column}
+variable, minus the value of the @code{right-margin} property of the
+character after point.
address@hidden defun
+
address@hidden Command move-to-left-margin &optional n force
+This function moves point to the left margin of the current line.  The
+column moved to is determined by calling the function
address@hidden  If the argument @var{n} is address@hidden,
address@hidden moves forward @address@hidden lines first.
+
+If @var{force} is address@hidden, that says to fix the line's
+indentation if that doesn't match the left margin value.
address@hidden deffn
+
address@hidden delete-to-left-margin &optional from to
+This function removes left margin indentation from the text between
address@hidden and @var{to}.  The amount of indentation to delete is
+determined by calling @code{current-left-margin}.  In no case does this
+function delete non-whitespace.  If @var{from} and @var{to} are omitted,
+they default to the whole buffer.
address@hidden defun
+
address@hidden indent-to-left-margin
+This function adjusts the indentation at the beginning of the current
+line to the value specified by the variable @code{left-margin}.  (That
+may involve either inserting or deleting whitespace.)  This function
+is value of @code{indent-line-function} in Paragraph-Indent Text mode.
address@hidden defun
+
address@hidden left-margin
+This variable specifies the base left margin column.  In Fundamental
+mode, @kbd{C-j} indents to this column.  This variable automatically
+becomes buffer-local when set in any fashion.
address@hidden defvar
+
address@hidden fill-nobreak-predicate
+This variable gives major modes a way to specify not to break a line
+at certain places.  Its value should be a list of functions.  Whenever
+filling considers breaking the line at a certain place in the buffer,
+it calls each of these functions with no arguments and with point
+located at that place.  If any of the functions returns
address@hidden, then the line won't be broken there.
address@hidden defvar
+
address@hidden Adaptive Fill
address@hidden Adaptive Fill Mode
address@hidden @cindex Adaptive Fill mode  "adaptive-fill-mode" is adjacent.
+
+  When @dfn{Adaptive Fill Mode} is enabled, Emacs determines the fill
+prefix automatically from the text in each paragraph being filled
+rather than using a predetermined value.  During filling, this fill
+prefix gets inserted at the start of the second and subsequent lines
+of the paragraph as described in @ref{Filling}, and in @ref{Auto
+Filling}.
+
address@hidden adaptive-fill-mode
+Adaptive Fill mode is enabled when this variable is address@hidden
+It is @code{t} by default.
address@hidden defopt
+
address@hidden fill-context-prefix from to
+This function implements the heart of Adaptive Fill mode; it chooses a
+fill prefix based on the text between @var{from} and @var{to},
+typically the start and end of a paragraph.  It does this by looking
+at the first two lines of the paragraph, based on the variables
+described below.
address@hidden The optional argument first-line-regexp is not documented
address@hidden because it exists for internal purposes and might be eliminated
address@hidden in the future.
+
+Usually, this function returns the fill prefix, a string.  However,
+before doing this, the function makes a final check (not specially
+mentioned in the following) that a line starting with this prefix
+wouldn't look like the start of a paragraph.  Should this happen, the
+function signals the anomaly by returning @code{nil} instead.
+
+In detail, @code{fill-context-prefix} does this:
+
address@hidden
address@hidden
+It takes a candidate for the fill prefix from the first line---it
+tries first the function in @code{adaptive-fill-function} (if any),
+then the regular expression @code{adaptive-fill-regexp} (see below).
+The first address@hidden result of these, or the empty string if
+they're both @code{nil}, becomes the first line's candidate.
address@hidden
+If the paragraph has as yet only one line, the function tests the
+validity of the prefix candidate just found.  The function then
+returns the candidate if it's valid, or a string of spaces otherwise.
+(see the description of @code{adaptive-fill-first-line-regexp} below).
address@hidden
+When the paragraph already has two lines, the function next looks for
+a prefix candidate on the second line, in just the same way it did for
+the first line.  If it doesn't find one, it returns @code{nil}.
address@hidden
+The function now compares the two candidate prefixes heuristically: if
+the non-whitespace characters in the line 2 candidate occur in the
+same order in the line 1 candidate, the function returns the line 2
+candidate.  Otherwise, it returns the largest initial substring which
+is common to both candidates (which might be the empty string).
address@hidden enumerate
address@hidden defun
+
address@hidden adaptive-fill-regexp
+Adaptive Fill mode matches this regular expression against the text
+starting after the left margin whitespace (if any) on a line; the
+characters it matches are that line's candidate for the fill prefix.
+
+The default value matches whitespace with certain punctuation
+characters intermingled.
address@hidden defopt
+
address@hidden adaptive-fill-first-line-regexp
+Used only in one-line paragraphs, this regular expression acts as an
+additional check of the validity of the one available candidate fill
+prefix: the candidate must match this regular expression, or match
address@hidden  If it doesn't, @code{fill-context-prefix}
+replaces the candidate with a string of spaces ``of the same width''
+as it.
+
+The default value of this variable is @address@hidden"\\`[ \t]*\\'"}}, which
+matches only a string of whitespace.  The effect of this default is to
+force the fill prefixes found in one-line paragraphs always to be pure
+whitespace.
address@hidden defopt
+
address@hidden adaptive-fill-function
+You can specify more complex ways of choosing a fill prefix
+automatically by setting this variable to a function.  The function is
+called with point after the left margin (if any) of a line, and it
+must preserve point.  It should return either ``that line's'' fill
+prefix or @code{nil}, meaning it has failed to determine a prefix.
address@hidden defopt
+
address@hidden Auto Filling
address@hidden  node-name,  next,  previous,  up
address@hidden Auto Filling
address@hidden filling, automatic
address@hidden Auto Fill mode
+
+  Auto Fill mode is a minor mode that fills lines automatically as text
+is inserted.  This section describes the hook used by Auto Fill mode.
+For a description of functions that you can call explicitly to fill and
+justify existing text, see @ref{Filling}.
+
+  Auto Fill mode also enables the functions that change the margins and
+justification style to refill portions of the text.  @xref{Margins}.
+
address@hidden auto-fill-function
+The value of this buffer-local variable should be a function (of no
+arguments) to be called after self-inserting a character from the table
address@hidden  It may be @code{nil}, in which case nothing
+special is done in that case.
+
+The value of @code{auto-fill-function} is @code{do-auto-fill} when
+Auto-Fill mode is enabled.  That is a function whose sole purpose is to
+implement the usual strategy for breaking a line.
+
address@hidden
+In older Emacs versions, this variable was named @code{auto-fill-hook},
+but since it is not called with the standard convention for hooks, it
+was renamed to @code{auto-fill-function} in version 19.
address@hidden quotation
address@hidden defvar
+
address@hidden normal-auto-fill-function
+This variable specifies the function to use for
address@hidden, if and when Auto Fill is turned on.  Major
+modes can set buffer-local values for this variable to alter how Auto
+Fill works.
address@hidden defvar
+
address@hidden auto-fill-chars
+A char table of characters which invoke @code{auto-fill-function} when
+self-inserted---space and newline in most language environments.  They
+have an entry @code{t} in the table.
address@hidden defvar
+
address@hidden Sorting
address@hidden Sorting Text
address@hidden sorting text
+
+  The sorting functions described in this section all rearrange text in
+a buffer.  This is in contrast to the function @code{sort}, which
+rearranges the order of the elements of a list (@pxref{Rearrangement}).
+The values returned by these functions are not meaningful.
+
address@hidden sort-subr reverse nextrecfun endrecfun &optional startkeyfun 
endkeyfun predicate
+This function is the general text-sorting routine that subdivides a
+buffer into records and then sorts them.  Most of the commands in this
+section use this function.
+
+To understand how @code{sort-subr} works, consider the whole accessible
+portion of the buffer as being divided into disjoint pieces called
address@hidden records}.  The records may or may not be contiguous, but they
+must not overlap.  A portion of each sort record (perhaps all of it) is
+designated as the sort key.  Sorting rearranges the records in order by
+their sort keys.
+
+Usually, the records are rearranged in order of ascending sort key.
+If the first argument to the @code{sort-subr} function, @var{reverse},
+is address@hidden, the sort records are rearranged in order of
+descending sort key.
+
+The next four arguments to @code{sort-subr} are functions that are
+called to move point across a sort record.  They are called many times
+from within @code{sort-subr}.
+
address@hidden
address@hidden
address@hidden is called with point at the end of a record.  This
+function moves point to the start of the next record.  The first record
+is assumed to start at the position of point when @code{sort-subr} is
+called.  Therefore, you should usually move point to the beginning of
+the buffer before calling @code{sort-subr}.
+
+This function can indicate there are no more sort records by leaving
+point at the end of the buffer.
+
address@hidden
address@hidden is called with point within a record.  It moves point to
+the end of the record.
+
address@hidden
address@hidden is called to move point from the start of a record to
+the start of the sort key.  This argument is optional; if it is omitted,
+the whole record is the sort key.  If supplied, the function should
+either return a address@hidden value to be used as the sort key, or
+return @code{nil} to indicate that the sort key is in the buffer
+starting at point.  In the latter case, @var{endkeyfun} is called to
+find the end of the sort key.
+
address@hidden
address@hidden is called to move point from the start of the sort key
+to the end of the sort key.  This argument is optional.  If
address@hidden returns @code{nil} and this argument is omitted (or
address@hidden), then the sort key extends to the end of the record.  There
+is no need for @var{endkeyfun} if @var{startkeyfun} returns a
address@hidden value.
address@hidden enumerate
+
+The argument @var{predicate} is the function to use to compare keys.
+If keys are numbers, it defaults to @code{<}; otherwise it defaults to
address@hidden<}.
+
+As an example of @code{sort-subr}, here is the complete function
+definition for @code{sort-lines}:
+
address@hidden
address@hidden
+;; @r{Note that the first two lines of doc string}
+;; @r{are effectively one line when viewed by a user.}
+(defun sort-lines (reverse beg end)
+  "Sort lines in region alphabetically;\
+ argument means descending order.
+Called from a program, there are three arguments:
address@hidden group
address@hidden
+REVERSE (non-nil means reverse order),\
+ BEG and END (region to sort).
+The variable `sort-fold-case' determines\
+ whether alphabetic case affects
+the sort order."
address@hidden group
address@hidden
+  (interactive "P\nr")
+  (save-excursion
+    (save-restriction
+      (narrow-to-region beg end)
+      (goto-char (point-min))
+      (let ((inhibit-field-text-motion t))
+        (sort-subr reverse 'forward-line 'end-of-line)))))
address@hidden group
address@hidden example
+
+Here @code{forward-line} moves point to the start of the next record,
+and @code{end-of-line} moves point to the end of record.  We do not pass
+the arguments @var{startkeyfun} and @var{endkeyfun}, because the entire
+record is used as the sort key.
+
+The @code{sort-paragraphs} function is very much the same, except that
+its @code{sort-subr} call looks like this:
+
address@hidden
address@hidden
+(sort-subr reverse
+           (function
+             (lambda ()
+               (while (and (not (eobp))
+                      (looking-at paragraph-separate))
+                 (forward-line 1))))
+           'forward-paragraph)
address@hidden group
address@hidden example
+
+Markers pointing into any sort records are left with no useful
+position after @code{sort-subr} returns.
address@hidden defun
+
address@hidden sort-fold-case
+If this variable is address@hidden, @code{sort-subr} and the other
+buffer sorting functions ignore case when comparing strings.
address@hidden defopt
+
address@hidden Command sort-regexp-fields reverse record-regexp key-regexp 
start end
+This command sorts the region between @var{start} and @var{end}
+alphabetically as specified by @var{record-regexp} and @var{key-regexp}.
+If @var{reverse} is a negative integer, then sorting is in reverse
+order.
+
+Alphabetical sorting means that two sort keys are compared by
+comparing the first characters of each, the second characters of each,
+and so on.  If a mismatch is found, it means that the sort keys are
+unequal; the sort key whose character is less at the point of first
+mismatch is the lesser sort key.  The individual characters are compared
+according to their numerical character codes in the Emacs character set.
+
+The value of the @var{record-regexp} argument specifies how to divide
+the buffer into sort records.  At the end of each record, a search is
+done for this regular expression, and the text that matches it is taken
+as the next record.  For example, the regular expression @samp{^.+$},
+which matches lines with at least one character besides a newline, would
+make each such line into a sort record.  @xref{Regular Expressions}, for
+a description of the syntax and meaning of regular expressions.
+
+The value of the @var{key-regexp} argument specifies what part of each
+record is the sort key.  The @var{key-regexp} could match the whole
+record, or only a part.  In the latter case, the rest of the record has
+no effect on the sorted order of records, but it is carried along when
+the record moves to its new position.
+
+The @var{key-regexp} argument can refer to the text matched by a
+subexpression of @var{record-regexp}, or it can be a regular expression
+on its own.
+
+If @var{key-regexp} is:
+
address@hidden @asis
address@hidden @address@hidden
+then the text matched by the @var{digit}th @samp{\(...\)} parenthesis
+grouping in @var{record-regexp} is the sort key.
+
address@hidden @samp{\&}
+then the whole record is the sort key.
+
address@hidden a regular expression
+then @code{sort-regexp-fields} searches for a match for the regular
+expression within the record.  If such a match is found, it is the sort
+key.  If there is no match for @var{key-regexp} within a record then
+that record is ignored, which means its position in the buffer is not
+changed.  (The other records may move around it.)
address@hidden table
+
+For example, if you plan to sort all the lines in the region by the
+first word on each line starting with the letter @samp{f}, you should
+set @var{record-regexp} to @samp{^.*$} and set @var{key-regexp} to
address@hidden<f\w*\>}.  The resulting expression looks like this:
+
address@hidden
address@hidden
+(sort-regexp-fields nil "^.*$" "\\<f\\w*\\>"
+                    (region-beginning)
+                    (region-end))
address@hidden group
address@hidden example
+
+If you call @code{sort-regexp-fields} interactively, it prompts for
address@hidden and @var{key-regexp} in the minibuffer.
address@hidden deffn
+
address@hidden Command sort-lines reverse start end
+This command alphabetically sorts lines in the region between
address@hidden and @var{end}.  If @var{reverse} is address@hidden, the sort
+is in reverse order.
address@hidden deffn
+
address@hidden Command sort-paragraphs reverse start end
+This command alphabetically sorts paragraphs in the region between
address@hidden and @var{end}.  If @var{reverse} is address@hidden, the sort
+is in reverse order.
address@hidden deffn
+
address@hidden Command sort-pages reverse start end
+This command alphabetically sorts pages in the region between
address@hidden and @var{end}.  If @var{reverse} is address@hidden, the sort
+is in reverse order.
address@hidden deffn
+
address@hidden Command sort-fields field start end
+This command sorts lines in the region between @var{start} and
address@hidden, comparing them alphabetically by the @var{field}th field
+of each line.  Fields are separated by whitespace and numbered starting
+from 1.  If @var{field} is negative, sorting is by the
address@hidden@address@hidden field from the end of the line.  This command
+is useful for sorting tables.
address@hidden deffn
+
address@hidden Command sort-numeric-fields field start end
+This command sorts lines in the region between @var{start} and
address@hidden, comparing them numerically by the @var{field}th field of
+each line.  Fields are separated by whitespace and numbered starting
+from 1.  The specified field must contain a number in each line of the
+region.  Numbers starting with 0 are treated as octal, and numbers
+starting with @samp{0x} are treated as hexadecimal.
+
+If @var{field} is negative, sorting is by the
address@hidden@address@hidden field from the end of the line.  This
+command is useful for sorting tables.
address@hidden deffn
+
address@hidden sort-numeric-base
+This variable specifies the default radix for
address@hidden to parse numbers.
address@hidden defopt
+
address@hidden Command sort-columns reverse &optional beg end
+This command sorts the lines in the region between @var{beg} and
address@hidden, comparing them alphabetically by a certain range of
+columns.  The column positions of @var{beg} and @var{end} bound the
+range of columns to sort on.
+
+If @var{reverse} is address@hidden, the sort is in reverse order.
+
+One unusual thing about this command is that the entire line
+containing position @var{beg}, and the entire line containing position
address@hidden, are included in the region sorted.
+
+Note that @code{sort-columns} rejects text that contains tabs, because
+tabs could be split across the specified columns.  Use @kbd{M-x
+untabify} to convert tabs to spaces before sorting.
+
+When possible, this command actually works by calling the @code{sort}
+utility program.
address@hidden deffn
+
address@hidden Columns
address@hidden  node-name,  next,  previous,  up
address@hidden Counting Columns
address@hidden columns
address@hidden counting columns
address@hidden horizontal position
+
+  The column functions convert between a character position (counting
+characters from the beginning of the buffer) and a column position
+(counting screen characters from the beginning of a line).
+
+  These functions count each character according to the number of
+columns it occupies on the screen.  This means control characters count
+as occupying 2 or 4 columns, depending upon the value of
address@hidden, and tabs count as occupying a number of columns that
+depends on the value of @code{tab-width} and on the column where the tab
+begins.  @xref{Usual Display}.
+
+  Column number computations ignore the width of the window and the
+amount of horizontal scrolling.  Consequently, a column value can be
+arbitrarily high.  The first (or leftmost) column is numbered 0.  They
+also ignore overlays and text properties, aside from invisibility.
+
address@hidden current-column
+This function returns the horizontal position of point, measured in
+columns, counting from 0 at the left margin.  The column position is the
+sum of the widths of all the displayed representations of the characters
+between the start of the current line and point.
+
+For an example of using @code{current-column}, see the description of
address@hidden in @ref{Text Lines}.
address@hidden defun
+
address@hidden move-to-column column &optional force
+This function moves point to @var{column} in the current line.  The
+calculation of @var{column} takes into account the widths of the
+displayed representations of the characters between the start of the
+line and point.
+
+If column @var{column} is beyond the end of the line, point moves to the
+end of the line.  If @var{column} is negative, point moves to the
+beginning of the line.
+
+If it is impossible to move to column @var{column} because that is in
+the middle of a multicolumn character such as a tab, point moves to the
+end of that character.  However, if @var{force} is address@hidden, and
address@hidden is in the middle of a tab, then @code{move-to-column}
+converts the tab into spaces so that it can move precisely to column
address@hidden  Other multicolumn characters can cause anomalies despite
address@hidden, since there is no way to split them.
+
+The argument @var{force} also has an effect if the line isn't long
+enough to reach column @var{column}; if it is @code{t}, that means to
+add whitespace at the end of the line to reach that column.
+
+If @var{column} is not an integer, an error is signaled.
+
+The return value is the column number actually moved to.
address@hidden defun
+
address@hidden Indentation
address@hidden Indentation
address@hidden indentation
+
+  The indentation functions are used to examine, move to, and change
+whitespace that is at the beginning of a line.  Some of the functions
+can also change whitespace elsewhere on a line.  Columns and indentation
+count from zero at the left margin.
+
address@hidden
+* Primitive Indent::      Functions used to count and insert indentation.
+* Mode-Specific Indent::  Customize indentation for different modes.
+* Region Indent::         Indent all the lines in a region.
+* Relative Indent::       Indent the current line based on previous lines.
+* Indent Tabs::           Adjustable, typewriter-like tab stops.
+* Motion by Indent::      Move to first non-blank character.
address@hidden menu
+
address@hidden Primitive Indent
address@hidden Indentation Primitives
+
+  This section describes the primitive functions used to count and
+insert indentation.  The functions in the following sections use these
+primitives.  @xref{Width}, for related functions.
+
address@hidden current-indentation
address@hidden !!Type Primitive Function
address@hidden !!SourceFile indent.c
+This function returns the indentation of the current line, which is
+the horizontal position of the first nonblank character.  If the
+contents are entirely blank, then this is the horizontal position of the
+end of the line.
address@hidden defun
+
address@hidden Command indent-to column &optional minimum
address@hidden !!Type Primitive Function
address@hidden !!SourceFile indent.c
+This function indents from point with tabs and spaces until @var{column}
+is reached.  If @var{minimum} is specified and address@hidden, then at
+least that many spaces are inserted even if this requires going beyond
address@hidden  Otherwise the function does nothing if point is already
+beyond @var{column}.  The value is the column at which the inserted
+indentation ends.
+
+The inserted whitespace characters inherit text properties from the
+surrounding text (usually, from the preceding text only).  @xref{Sticky
+Properties}.
address@hidden deffn
+
address@hidden indent-tabs-mode
address@hidden !!SourceFile indent.c
+If this variable is address@hidden, indentation functions can insert
+tabs as well as spaces.  Otherwise, they insert only spaces.  Setting
+this variable automatically makes it buffer-local in the current buffer.
address@hidden defopt
+
address@hidden Mode-Specific Indent
address@hidden Indentation Controlled by Major Mode
+
+  An important function of each major mode is to customize the @key{TAB}
+key to indent properly for the language being edited.  This section
+describes the mechanism of the @key{TAB} key and how to control it.
+The functions in this section return unpredictable values.
+
address@hidden indent-line-function
+This variable's value is the function to be used by @key{TAB} (and
+various commands) to indent the current line.  The command
address@hidden does no more than call this function.
+
+In Lisp mode, the value is the symbol @code{lisp-indent-line}; in C
+mode, @code{c-indent-line}; in Fortran mode, @code{fortran-indent-line}.
+The default value is @code{indent-relative}.
address@hidden defvar
+
address@hidden Command indent-according-to-mode
+This command calls the function in @code{indent-line-function} to
+indent the current line in a way appropriate for the current major mode.
address@hidden deffn
+
address@hidden Command indent-for-tab-command
+This command calls the function in @code{indent-line-function} to indent
+the current line; however, if that function is
address@hidden, @code{insert-tab} is called instead.  (That
+is a trivial command that inserts a tab character.)
address@hidden deffn
+
address@hidden Command newline-and-indent
address@hidden !!SourceFile simple.el
+This function inserts a newline, then indents the new line (the one
+following the newline just inserted) according to the major mode.
+
+It does indentation by calling the current @code{indent-line-function}.
+In programming language modes, this is the same thing @key{TAB} does,
+but in some text modes, where @key{TAB} inserts a tab,
address@hidden indents to the column specified by
address@hidden
address@hidden deffn
+
address@hidden Command reindent-then-newline-and-indent
address@hidden !!SourceFile simple.el
+This command reindents the current line, inserts a newline at point,
+and then indents the new line (the one following the newline just
+inserted).
+
+This command does indentation on both lines according to the current
+major mode, by calling the current value of @code{indent-line-function}.
+In programming language modes, this is the same thing @key{TAB} does,
+but in some text modes, where @key{TAB} inserts a tab,
address@hidden indents to the column specified
+by @code{left-margin}.
address@hidden deffn
+
address@hidden Region Indent
address@hidden Indenting an Entire Region
+
+  This section describes commands that indent all the lines in the
+region.  They return unpredictable values.
+
address@hidden Command indent-region start end to-column
+This command indents each nonblank line starting between @var{start}
+(inclusive) and @var{end} (exclusive).  If @var{to-column} is
address@hidden, @code{indent-region} indents each nonblank line by calling
+the current mode's indentation function, the value of
address@hidden
+
+If @var{to-column} is address@hidden, it should be an integer
+specifying the number of columns of indentation; then this function
+gives each line exactly that much indentation, by either adding or
+deleting whitespace.
+
+If there is a fill prefix, @code{indent-region} indents each line
+by making it start with the fill prefix.
address@hidden deffn
+
address@hidden indent-region-function
+The value of this variable is a function that can be used by
address@hidden as a short cut.  It should take two arguments, the
+start and end of the region.  You should design the function so
+that it will produce the same results as indenting the lines of the
+region one by one, but presumably faster.
+
+If the value is @code{nil}, there is no short cut, and
address@hidden actually works line by line.
+
+A short-cut function is useful in modes such as C mode and Lisp mode,
+where the @code{indent-line-function} must scan from the beginning of
+the function definition: applying it to each line would be quadratic in
+time.  The short cut can update the scan information as it moves through
+the lines indenting them; this takes linear time.  In a mode where
+indenting a line individually is fast, there is no need for a short cut.
+
address@hidden with a address@hidden argument @var{to-column} has
+a different meaning and does not use this variable.
address@hidden defvar
+
address@hidden Command indent-rigidly start end count
address@hidden !!SourceFile indent.el
+This command indents all lines starting between @var{start}
+(inclusive) and @var{end} (exclusive) sideways by @var{count} columns.
+This ``preserves the shape'' of the affected region, moving it as a
+rigid unit.  Consequently, this command is useful not only for indenting
+regions of unindented text, but also for indenting regions of formatted
+code.
+
+For example, if @var{count} is 3, this command adds 3 columns of
+indentation to each of the lines beginning in the region specified.
+
+In Mail mode, @kbd{C-c C-y} (@code{mail-yank-original}) uses
address@hidden to indent the text copied from the message being
+replied to.
address@hidden deffn
+
address@hidden indent-code-rigidly start end columns &optional nochange-regexp
+This is like @code{indent-rigidly}, except that it doesn't alter lines
+that start within strings or comments.
+
+In addition, it doesn't alter a line if @var{nochange-regexp} matches at
+the beginning of the line (if @var{nochange-regexp} is address@hidden).
address@hidden defun
+
address@hidden Relative Indent
address@hidden Indentation Relative to Previous Lines
+
+  This section describes two commands that indent the current line
+based on the contents of previous lines.
+
address@hidden Command indent-relative &optional unindented-ok
+This command inserts whitespace at point, extending to the same
+column as the next @dfn{indent point} of the previous nonblank line.  An
+indent point is a non-whitespace character following whitespace.  The
+next indent point is the first one at a column greater than the current
+column of point.  For example, if point is underneath and to the left of
+the first non-blank character of a line of text, it moves to that column
+by inserting whitespace.
+
+If the previous nonblank line has no next indent point (i.e., none at a
+great enough column position), @code{indent-relative} either does
+nothing (if @var{unindented-ok} is address@hidden) or calls
address@hidden  Thus, if point is underneath and to the right
+of the last column of a short line of text, this command ordinarily
+moves point to the next tab stop by inserting whitespace.
+
+The return value of @code{indent-relative} is unpredictable.
+
+In the following example, point is at the beginning of the second
+line:
+
address@hidden
address@hidden
+            This line is indented twelve spaces.
address@hidden quick brown fox jumped.
address@hidden group
address@hidden example
+
address@hidden
+Evaluation of the expression @code{(indent-relative nil)} produces the
+following:
+
address@hidden
address@hidden
+            This line is indented twelve spaces.
+            @point{}The quick brown fox jumped.
address@hidden group
address@hidden example
+
+  In this next example, point is between the @samp{m} and @samp{p} of
address@hidden:
+
address@hidden
address@hidden
+            This line is indented twelve spaces.
+The quick brown fox address@hidden
address@hidden group
address@hidden example
+
address@hidden
+Evaluation of the expression @code{(indent-relative nil)} produces the
+following:
+
address@hidden
address@hidden
+            This line is indented twelve spaces.
+The quick brown fox jum  @point{}ped.
address@hidden group
address@hidden example
address@hidden deffn
+
address@hidden Command indent-relative-maybe
address@hidden !!SourceFile indent.el
+This command indents the current line like the previous nonblank line,
+by calling @code{indent-relative} with @code{t} as the
address@hidden argument.  The return value is unpredictable.
+
+If the previous nonblank line has no indent points beyond the current
+column, this command does nothing.
address@hidden deffn
+
address@hidden Indent Tabs
address@hidden  node-name,  next,  previous,  up
address@hidden Adjustable ``Tab Stops''
address@hidden tabs stops for indentation
+
+  This section explains the mechanism for user-specified ``tab stops''
+and the mechanisms that use and set them.  The name ``tab stops'' is
+used because the feature is similar to that of the tab stops on a
+typewriter.  The feature works by inserting an appropriate number of
+spaces and tab characters to reach the next tab stop column; it does not
+affect the display of tab characters in the buffer (@pxref{Usual
+Display}).  Note that the @key{TAB} character as input uses this tab
+stop feature only in a few major modes, such as Text mode.
address@hidden Stops,,, emacs, The GNU Emacs Manual}.
+
address@hidden Command tab-to-tab-stop
+This command inserts spaces or tabs before point, up to the next tab
+stop column defined by @code{tab-stop-list}.  It searches the list for
+an element greater than the current column number, and uses that element
+as the column to indent to.  It does nothing if no such element is
+found.
address@hidden deffn
+
address@hidden tab-stop-list
+This variable is the list of tab stop columns used by
address@hidden  The elements should be integers in increasing
+order.  The tab stop columns need not be evenly spaced.
+
+Use @kbd{M-x edit-tab-stops} to edit the location of tab stops
+interactively.
address@hidden defopt
+
address@hidden Motion by Indent
address@hidden Indentation-Based Motion Commands
+
+  These commands, primarily for interactive use, act based on the
+indentation in the text.
+
address@hidden Command back-to-indentation
address@hidden !!SourceFile simple.el
+This command moves point to the first non-whitespace character in the
+current line (which is the line in which point is located).  It returns
address@hidden
address@hidden deffn
+
address@hidden Command backward-to-indentation &optional arg
address@hidden !!SourceFile simple.el
+This command moves point backward @var{arg} lines and then to the
+first nonblank character on that line.  It returns @code{nil}.
+If @var{arg} is omitted or @code{nil}, it defaults to 1.
address@hidden deffn
+
address@hidden Command forward-to-indentation &optional arg
address@hidden !!SourceFile simple.el
+This command moves point forward @var{arg} lines and then to the first
+nonblank character on that line.  It returns @code{nil}.
+If @var{arg} is omitted or @code{nil}, it defaults to 1.
address@hidden deffn
+
address@hidden Case Changes
address@hidden  node-name,  next,  previous,  up
address@hidden Case Changes
address@hidden case conversion in buffers
+
+  The case change commands described here work on text in the current
+buffer.  @xref{Case Conversion}, for case conversion functions that work
+on strings and characters.  @xref{Case Tables}, for how to customize
+which characters are upper or lower case and how to convert them.
+
address@hidden Command capitalize-region start end
+This function capitalizes all words in the region defined by
address@hidden and @var{end}.  To capitalize means to convert each word's
+first character to upper case and convert the rest of each word to lower
+case.  The function returns @code{nil}.
+
+If one end of the region is in the middle of a word, the part of the
+word within the region is treated as an entire word.
+
+When @code{capitalize-region} is called interactively, @var{start} and
address@hidden are point and the mark, with the smallest first.
+
address@hidden
address@hidden
+---------- Buffer: foo ----------
+This is the contents of the 5th foo.
+---------- Buffer: foo ----------
address@hidden group
+
address@hidden
+(capitalize-region 1 44)
address@hidden nil
+
+---------- Buffer: foo ----------
+This Is The Contents Of The 5th Foo.
+---------- Buffer: foo ----------
address@hidden group
address@hidden example
address@hidden deffn
+
address@hidden Command downcase-region start end
+This function converts all of the letters in the region defined by
address@hidden and @var{end} to lower case.  The function returns
address@hidden
+
+When @code{downcase-region} is called interactively, @var{start} and
address@hidden are point and the mark, with the smallest first.
address@hidden deffn
+
address@hidden Command upcase-region start end
+This function converts all of the letters in the region defined by
address@hidden and @var{end} to upper case.  The function returns
address@hidden
+
+When @code{upcase-region} is called interactively, @var{start} and
address@hidden are point and the mark, with the smallest first.
address@hidden deffn
+
address@hidden Command capitalize-word count
+This function capitalizes @var{count} words after point, moving point
+over as it does.  To capitalize means to convert each word's first
+character to upper case and convert the rest of each word to lower case.
+If @var{count} is negative, the function capitalizes the
address@hidden@var{count} previous words but does not move point.  The value
+is @code{nil}.
+
+If point is in the middle of a word, the part of the word before point
+is ignored when moving forward.  The rest is treated as an entire word.
+
+When @code{capitalize-word} is called interactively, @var{count} is
+set to the numeric prefix argument.
address@hidden deffn
+
address@hidden Command downcase-word count
+This function converts the @var{count} words after point to all lower
+case, moving point over as it does.  If @var{count} is negative, it
+converts the @address@hidden previous words but does not move point.
+The value is @code{nil}.
+
+When @code{downcase-word} is called interactively, @var{count} is set
+to the numeric prefix argument.
address@hidden deffn
+
address@hidden Command upcase-word count
+This function converts the @var{count} words after point to all upper
+case, moving point over as it does.  If @var{count} is negative, it
+converts the @address@hidden previous words but does not move point.
+The value is @code{nil}.
+
+When @code{upcase-word} is called interactively, @var{count} is set to
+the numeric prefix argument.
address@hidden deffn
+
address@hidden Text Properties
address@hidden Text Properties
address@hidden text properties
address@hidden attributes of text
address@hidden properties of text
+
+  Each character position in a buffer or a string can have a @dfn{text
+property list}, much like the property list of a symbol (@pxref{Property
+Lists}).  The properties belong to a particular character at a
+particular place, such as, the letter @samp{T} at the beginning of this
+sentence or the first @samp{o} in @samp{foo}---if the same character
+occurs in two different places, the two occurrences in general have
+different properties.
+
+  Each property has a name and a value.  Both of these can be any Lisp
+object, but the name is normally a symbol.  Typically each property
+name symbol is used for a particular purpose; for instance, the text
+property @code{face} specifies the faces for displaying the character
+(@pxref{Special Properties}).  The usual way to access the property
+list is to specify a name and ask what value corresponds to it.
+
+  If a character has a @code{category} property, we call it the
address@hidden category} of the character.  It should be a symbol.  The
+properties of the symbol serve as defaults for the properties of the
+character.
+
+  Copying text between strings and buffers preserves the properties
+along with the characters; this includes such diverse functions as
address@hidden, @code{insert}, and @code{buffer-substring}.
+
address@hidden
+* Examining Properties::   Looking at the properties of one character.
+* Changing Properties::           Setting the properties of a range of text.
+* Property Search::       Searching for where a property changes value.
+* Special Properties::    Particular properties with special meanings.
+* Format Properties::      Properties for representing formatting of text.
+* Sticky Properties::      How inserted text gets properties from
+                             neighboring text.
+* Lazy Properties::        Computing text properties in a lazy fashion
+                             only when text is examined.
+* Clickable Text::         Using text properties to make regions of text
+                             do something when you click on them.
+* Links and Mouse-1::      How to make @key{Mouse-1} follow a link.
+* Fields::                 The @code{field} property defines
+                             fields within the buffer.
+* Not Intervals::         Why text properties do not use
+                            Lisp-visible text intervals.
address@hidden menu
+
address@hidden Examining Properties
address@hidden Examining Text Properties
+
+  The simplest way to examine text properties is to ask for the value of
+a particular property of a particular character.  For that, use
address@hidden  Use @code{text-properties-at} to get the
+entire property list of a character.  @xref{Property Search}, for
+functions to examine the properties of a number of characters at once.
+
+  These functions handle both strings and buffers.  Keep in mind that
+positions in a string start from 0, whereas positions in a buffer start
+from 1.
+
address@hidden get-text-property pos prop &optional object
+This function returns the value of the @var{prop} property of the
+character after position @var{pos} in @var{object} (a buffer or
+string).  The argument @var{object} is optional and defaults to the
+current buffer.
+
+If there is no @var{prop} property strictly speaking, but the character
+has a property category that is a symbol, then @code{get-text-property} returns
+the @var{prop} property of that symbol.
address@hidden defun
+
address@hidden get-char-property position prop &optional object
+This function is like @code{get-text-property}, except that it checks
+overlays first and then text properties.  @xref{Overlays}.
+
+The argument @var{object} may be a string, a buffer, or a window.  If it
+is a window, then the buffer displayed in that window is used for text
+properties and overlays, but only the overlays active for that window
+are considered.  If @var{object} is a buffer, then all overlays in that
+buffer are considered, as well as text properties.  If @var{object} is a
+string, only text properties are considered, since strings never have
+overlays.
address@hidden defun
+
address@hidden get-char-property-and-overlay position prop &optional object
+This is like @code{get-char-property}, but gives extra information
+about the overlay that the property value comes from.
+
+Its value is a cons cell whose @sc{car} is the property value, the
+same value @code{get-char-property} would return with the same
+arguments.  Its @sc{cdr} is the overlay in which the property was
+found, or @code{nil}, if it was found as a text property or not found
+at all.
+
+If @var{position} is at the end of @var{object}, both the @sc{car} and
+the @sc{cdr} of the value are @code{nil}.
address@hidden defun
+
address@hidden char-property-alias-alist
+This variable holds an alist which maps property names to a list of
+alternative property names.  If a character does not specify a direct
+value for a property, the alternative property names are consulted in
+order; the first address@hidden value is used.  This variable takes
+precedence over @code{default-text-properties}, and @code{category}
+properties take precedence over this variable.
address@hidden defvar
+
address@hidden text-properties-at position &optional object
+This function returns the entire property list of the character at
address@hidden in the string or buffer @var{object}.  If @var{object} is
address@hidden, it defaults to the current buffer.
address@hidden defun
+
address@hidden default-text-properties
+This variable holds a property list giving default values for text
+properties.  Whenever a character does not specify a value for a
+property, neither directly, through a category symbol, or through
address@hidden, the value stored in this list is
+used instead.  Here is an example:
+
address@hidden
+(setq default-text-properties '(foo 69)
+      char-property-alias-alist nil)
+;; @r{Make sure character 1 has no properties of its own.}
+(set-text-properties 1 2 nil)
+;; @r{What we get, when we ask, is the default value.}
+(get-text-property 1 'foo)
+     @result{} 69
address@hidden example
address@hidden defvar
+
address@hidden Changing Properties
address@hidden Changing Text Properties
+
+  The primitives for changing properties apply to a specified range of
+text in a buffer or string.  The function @code{set-text-properties}
+(see end of section) sets the entire property list of the text in that
+range; more often, it is useful to add, change, or delete just certain
+properties specified by name.
+
+  Since text properties are considered part of the contents of the
+buffer (or string), and can affect how a buffer looks on the screen,
+any change in buffer text properties marks the buffer as modified.
+Buffer text property changes are undoable also (@pxref{Undo}).
+Positions in a string start from 0, whereas positions in a buffer
+start from 1.
+
address@hidden put-text-property start end prop value &optional object
+This function sets the @var{prop} property to @var{value} for the text
+between @var{start} and @var{end} in the string or buffer @var{object}.
+If @var{object} is @code{nil}, it defaults to the current buffer.
address@hidden defun
+
address@hidden add-text-properties start end props &optional object
+This function adds or overrides text properties for the text between
address@hidden and @var{end} in the string or buffer @var{object}.  If
address@hidden is @code{nil}, it defaults to the current buffer.
+
+The argument @var{props} specifies which properties to add.  It should
+have the form of a property list (@pxref{Property Lists}): a list whose
+elements include the property names followed alternately by the
+corresponding values.
+
+The return value is @code{t} if the function actually changed some
+property's value; @code{nil} otherwise (if @var{props} is @code{nil} or
+its values agree with those in the text).
+
+For example, here is how to set the @code{comment} and @code{face}
+properties of a range of text:
+
address@hidden
+(add-text-properties @var{start} @var{end}
+                     '(comment t face highlight))
address@hidden example
address@hidden defun
+
address@hidden remove-text-properties start end props &optional object
+This function deletes specified text properties from the text between
address@hidden and @var{end} in the string or buffer @var{object}.  If
address@hidden is @code{nil}, it defaults to the current buffer.
+
+The argument @var{props} specifies which properties to delete.  It
+should have the form of a property list (@pxref{Property Lists}): a list
+whose elements are property names alternating with corresponding values.
+But only the names matter---the values that accompany them are ignored.
+For example, here's how to remove the @code{face} property.
+
address@hidden
+(remove-text-properties @var{start} @var{end} '(face nil))
address@hidden example
+
+The return value is @code{t} if the function actually changed some
+property's value; @code{nil} otherwise (if @var{props} is @code{nil} or
+if no character in the specified text had any of those properties).
+
+To remove all text properties from certain text, use
address@hidden and specify @code{nil} for the new property
+list.
address@hidden defun
+
address@hidden remove-list-of-text-properties start end list-of-properties 
&optional object
+Like @code{remove-text-properties} except that
address@hidden is a list of property names only, not an
+alternating list of property names and values.
address@hidden defun
+
address@hidden set-text-properties start end props &optional object
+This function completely replaces the text property list for the text
+between @var{start} and @var{end} in the string or buffer @var{object}.
+If @var{object} is @code{nil}, it defaults to the current buffer.
+
+The argument @var{props} is the new property list.  It should be a list
+whose elements are property names alternating with corresponding values.
+
+After @code{set-text-properties} returns, all the characters in the
+specified range have identical properties.
+
+If @var{props} is @code{nil}, the effect is to get rid of all properties
+from the specified range of text.  Here's an example:
+
address@hidden
+(set-text-properties @var{start} @var{end} nil)
address@hidden example
+
+Do not rely on the return value of this function.
address@hidden defun
+
+  The easiest way to make a string with text properties
+is with @code{propertize}:
+
address@hidden propertize string &rest properties
+This function returns a copy of @var{string} which has the text
+properties @var{properties}.  These properties apply to all the
+characters in the string that is returned.  Here is an example that
+constructs a string with a @code{face} property and a @code{mouse-face}
+property:
+
address@hidden
+(propertize "foo" 'face 'italic
+            'mouse-face 'bold-italic)
+     @result{} #("foo" 0 3 (mouse-face bold-italic face italic))
address@hidden smallexample
+
+To put different properties on various parts of a string, you can
+construct each part with @code{propertize} and then combine them with
address@hidden:
+
address@hidden
+(concat
+ (propertize "foo" 'face 'italic
+             'mouse-face 'bold-italic)
+ " and "
+ (propertize "bar" 'face 'italic
+             'mouse-face 'bold-italic))
+     @result{} #("foo and bar"
+                 0 3 (face italic mouse-face bold-italic)
+                 3 8 nil
+                 8 11 (face italic mouse-face bold-italic))
address@hidden smallexample
address@hidden defun
+
+  See also the function @code{buffer-substring-no-properties}
+(@pxref{Buffer Contents}) which copies text from the buffer
+but does not copy its properties.
+
address@hidden Property Search
address@hidden Text Property Search Functions
+
+  In typical use of text properties, most of the time several or many
+consecutive characters have the same value for a property.  Rather than
+writing your programs to examine characters one by one, it is much
+faster to process chunks of text that have the same property value.
+
+  Here are functions you can use to do this.  They use @code{eq} for
+comparing property values.  In all cases, @var{object} defaults to the
+current buffer.
+
+  For high performance, it's very important to use the @var{limit}
+argument to these functions, especially the ones that search for a
+single property---otherwise, they may spend a long time scanning to the
+end of the buffer, if the property you are interested in does not change.
+
+  These functions do not move point; instead, they return a position (or
address@hidden).  Remember that a position is always between two characters;
+the position returned by these functions is between two characters with
+different properties.
+
address@hidden next-property-change pos &optional object limit
+The function scans the text forward from position @var{pos} in the
+string or buffer @var{object} till it finds a change in some text
+property, then returns the position of the change.  In other words, it
+returns the position of the first character beyond @var{pos} whose
+properties are not identical to those of the character just after
address@hidden
+
+If @var{limit} is address@hidden, then the scan ends at position
address@hidden  If there is no property change before that point,
address@hidden returns @var{limit}.
+
+The value is @code{nil} if the properties remain unchanged all the way
+to the end of @var{object} and @var{limit} is @code{nil}.  If the value
+is address@hidden, it is a position greater than or equal to @var{pos}.
+The value equals @var{pos} only when @var{limit} equals @var{pos}.
+
+Here is an example of how to scan the buffer by chunks of text within
+which all properties are constant:
+
address@hidden
+(while (not (eobp))
+  (let ((plist (text-properties-at (point)))
+        (next-change
+         (or (next-property-change (point) (current-buffer))
+             (point-max))))
+    @r{Process text from point to @address@hidden
+    (goto-char next-change)))
address@hidden smallexample
address@hidden defun
+
address@hidden previous-property-change pos &optional object limit
+This is like @code{next-property-change}, but scans back from @var{pos}
+instead of forward.  If the value is address@hidden, it is a position
+less than or equal to @var{pos}; it equals @var{pos} only if @var{limit}
+equals @var{pos}.
address@hidden defun
+
address@hidden next-single-property-change pos prop &optional object limit
+The function scans text for a change in the @var{prop} property, then
+returns the position of the change.  The scan goes forward from
+position @var{pos} in the string or buffer @var{object}.  In other
+words, this function returns the position of the first character
+beyond @var{pos} whose @var{prop} property differs from that of the
+character just after @var{pos}.
+
+If @var{limit} is address@hidden, then the scan ends at position
address@hidden  If there is no property change before that point,
address@hidden returns @var{limit}.
+
+The value is @code{nil} if the property remains unchanged all the way to
+the end of @var{object} and @var{limit} is @code{nil}.  If the value is
address@hidden, it is a position greater than or equal to @var{pos}; it
+equals @var{pos} only if @var{limit} equals @var{pos}.
address@hidden defun
+
address@hidden previous-single-property-change pos prop &optional object limit
+This is like @code{next-single-property-change}, but scans back from
address@hidden instead of forward.  If the value is address@hidden, it is a
+position less than or equal to @var{pos}; it equals @var{pos} only if
address@hidden equals @var{pos}.
address@hidden defun
+
address@hidden next-char-property-change pos &optional limit
+This is like @code{next-property-change} except that it considers
+overlay properties as well as text properties, and if no change is
+found before the end of the buffer, it returns the maximum buffer
+position rather than @code{nil} (in this sense, it resembles the
+corresponding overlay function @code{next-overlay-change}, rather than
address@hidden).  There is no @var{object} operand
+because this function operates only on the current buffer.  It returns
+the next address at which either kind of property changes.
address@hidden defun
+
address@hidden previous-char-property-change pos &optional limit
+This is like @code{next-char-property-change}, but scans back from
address@hidden instead of forward, and returns the minimum buffer
+position if no change is found.
address@hidden defun
+
address@hidden next-single-char-property-change pos prop &optional object limit
+This is like @code{next-single-property-change} except that it
+considers overlay properties as well as text properties, and if no
+change is found before the end of the @var{object}, it returns the
+maximum valid position in @var{object} rather than @code{nil}.  Unlike
address@hidden, this function @emph{does} have an
address@hidden operand; if @var{object} is not a buffer, only
+text-properties are considered.
address@hidden defun
+
address@hidden previous-single-char-property-change pos prop &optional object 
limit
+This is like @code{next-single-char-property-change}, but scans back
+from @var{pos} instead of forward, and returns the minimum valid
+position in @var{object} if no change is found.
address@hidden defun
+
address@hidden text-property-any start end prop value &optional object
+This function returns address@hidden if at least one character between
address@hidden and @var{end} has a property @var{prop} whose value is
address@hidden  More precisely, it returns the position of the first such
+character.  Otherwise, it returns @code{nil}.
+
+The optional fifth argument, @var{object}, specifies the string or
+buffer to scan.  Positions are relative to @var{object}.  The default
+for @var{object} is the current buffer.
address@hidden defun
+
address@hidden text-property-not-all start end prop value &optional object
+This function returns address@hidden if at least one character between
address@hidden and @var{end} does not have a property @var{prop} with value
address@hidden  More precisely, it returns the position of the first such
+character.  Otherwise, it returns @code{nil}.
+
+The optional fifth argument, @var{object}, specifies the string or
+buffer to scan.  Positions are relative to @var{object}.  The default
+for @var{object} is the current buffer.
address@hidden defun
+
address@hidden Special Properties
address@hidden Properties with Special Meanings
+
+  Here is a table of text property names that have special built-in
+meanings.  The following sections list a few additional special property
+names that control filling and property inheritance.  All other names
+have no standard meaning, and you can use them as you like.
+
+  Note: the properties @code{composition}, @code{display},
address@hidden and @code{intangible} can also cause point to move to
+an acceptable place, after each Emacs command.  @xref{Adjusting
+Point}.
+
address@hidden @code
address@hidden property category of text character
address@hidden category @r{(text property)}
address@hidden category
+If a character has a @code{category} property, we call it the
address@hidden category} of the character.  It should be a symbol.  The
+properties of this symbol serve as defaults for the properties of the
+character.
+
address@hidden face
address@hidden face codes of text
address@hidden face @r{(text property)}
+You can use the property @code{face} to control the font and color of
+text.  @xref{Faces}, for more information.
+
+In the simplest case, the value is a face name.  It can also be a list;
+then each element can be any of these possibilities;
+
address@hidden @bullet
address@hidden
+A face name (a symbol or string).
+
address@hidden
+A property list of face attributes.  This has the
+form (@var{keyword} @var{value} @dots{}), where each @var{keyword} is a
+face attribute name and @var{value} is a meaningful value for that
+attribute.  With this feature, you do not need to create a face each
+time you want to specify a particular attribute for certain text.
address@hidden Attributes}.
+
address@hidden
+A cons cell with the form @code{(foreground-color . @var{color-name})} or
address@hidden(background-color . @var{color-name})}.  These elements specify
+just the foreground color or just the background color.  @xref{Color
+Names}, for the supported forms of @var{color-name}.
+
+A cons cell of @code{(foreground-color . @var{color-name})} is equivalent to
+specifying @code{(:foreground @var{color-name})}; likewise for the
+background.
address@hidden itemize
+
+You can use Font Lock Mode (@pxref{Font Lock Mode}), to dynamically
+update @code{face} properties based on the contents of the text.
+
address@hidden font-lock-face
address@hidden font-lock-face @r{(text property)}
+The @code{font-lock-face} property is the same in all respects as the
address@hidden property, but its state of activation is controlled by
address@hidden  This can be advantageous for special buffers
+which are not intended to be user-editable, or for static areas of
+text which are always fontified in the same way.
address@hidden Fontification}.
+
+Strictly speaking, @code{font-lock-face} is not a built-in text
+property; rather, it is implemented in Font Lock mode using
address@hidden  @xref{Examining Properties}.
+
+This property is new in Emacs 22.1.
+
address@hidden mouse-face
address@hidden mouse-face @r{(text property)}
+The property @code{mouse-face} is used instead of @code{face} when the
+mouse is on or near the character.  For this purpose, ``near'' means
+that all text between the character and where the mouse is have the same
address@hidden property value.
+
address@hidden fontified
address@hidden fontified @r{(text property)}
+This property says whether the text is ready for display.  If
address@hidden, Emacs's redisplay routine calls the functions in
address@hidden (@pxref{Auto Faces}) to prepare this
+part of the buffer before it is displayed.  It is used internally by
+the ``just in time'' font locking code.
+
address@hidden display
+This property activates various features that change the
+way text is displayed.  For example, it can make text appear taller
+or shorter, higher or lower, wider or narrow, or replaced with an image.
address@hidden Property}.
+
address@hidden help-echo
address@hidden help-echo @r{(text property)}
address@hidden tooltip
address@hidden help-echo}
+If text has a string as its @code{help-echo} property, then when you
+move the mouse onto that text, Emacs displays that string in the echo
+area, or in the tooltip window (@pxref{Tooltips,,, emacs, The GNU Emacs
+Manual}).
+
+If the value of the @code{help-echo} property is a function, that
+function is called with three arguments, @var{window}, @var{object} and
address@hidden and should return a help string or @code{nil} for
+none.  The first argument, @var{window} is the window in which
+the help was found.  The second, @var{object}, is the buffer, overlay or
+string which had the @code{help-echo} property.  The @var{pos}
+argument is as follows:
+
address@hidden @bullet{}
address@hidden
+If @var{object} is a buffer, @var{pos} is the position in the buffer.
address@hidden
+If @var{object} is an overlay, that overlay has a @code{help-echo}
+property, and @var{pos} is the position in the overlay's buffer.
address@hidden
+If @var{object} is a string (an overlay string or a string displayed
+with the @code{display} property), @var{pos} is the position in that
+string.
address@hidden itemize
+
+If the value of the @code{help-echo} property is neither a function nor
+a string, it is evaluated to obtain a help string.
+
+You can alter the way help text is displayed by setting the variable
address@hidden (@pxref{Help display}).
+
+This feature is used in the mode line and for other active text.
+
address@hidden keymap
address@hidden keymap of character
address@hidden keymap @r{(text property)}
+The @code{keymap} property specifies an additional keymap for
+commands.  When this keymap applies, it is used for key lookup before
+the minor mode keymaps and before the buffer's local map.
address@hidden Keymaps}.  If the property value is a symbol, the
+symbol's function definition is used as the keymap.
+
+The property's value for the character before point applies if it is
address@hidden and rear-sticky, and the property's value for the
+character after point applies if it is address@hidden and
+front-sticky.  (For mouse clicks, the position of the click is used
+instead of the position of point.)
+
address@hidden local-map
address@hidden local-map @r{(text property)}
+This property works like @code{keymap} except that it specifies a
+keymap to use @emph{instead of} the buffer's local map.  For most
+purposes (perhaps all purposes), it is better to use the @code{keymap}
+property.
+
address@hidden syntax-table
+The @code{syntax-table} property overrides what the syntax table says
+about this particular character.  @xref{Syntax Properties}.
+
address@hidden read-only
address@hidden read-only character
address@hidden read-only @r{(text property)}
+If a character has the property @code{read-only}, then modifying that
+character is not allowed.  Any command that would do so gets an error,
address@hidden  If the property value is a string, that string
+is used as the error message.
+
+Insertion next to a read-only character is an error if inserting
+ordinary text there would inherit the @code{read-only} property due to
+stickiness.  Thus, you can control permission to insert next to
+read-only text by controlling the stickiness.  @xref{Sticky Properties}.
+
+Since changing properties counts as modifying the buffer, it is not
+possible to remove a @code{read-only} property unless you know the
+special trick: bind @code{inhibit-read-only} to a address@hidden value
+and then remove the property.  @xref{Read Only Buffers}.
+
address@hidden invisible
address@hidden invisible @r{(text property)}
+A address@hidden @code{invisible} property can make a character invisible
+on the screen.  @xref{Invisible Text}, for details.
+
address@hidden intangible
address@hidden intangible @r{(text property)}
+If a group of consecutive characters have equal and address@hidden
address@hidden properties, then you cannot place point between them.
+If you try to move point forward into the group, point actually moves to
+the end of the group.  If you try to move point backward into the group,
+point actually moves to the start of the group.
+
+If consecutive characters have unequal address@hidden
address@hidden properties, they belong to separate groups; each
+group is separately treated as described above.
+
+When the variable @code{inhibit-point-motion-hooks} is address@hidden,
+the @code{intangible} property is ignored.
+
address@hidden field
address@hidden field @r{(text property)}
+Consecutive characters with the same @code{field} property constitute a
address@hidden  Some motion functions including @code{forward-word} and
address@hidden stop moving at a field boundary.
address@hidden
+
address@hidden cursor
address@hidden cursor @r{(text property)}
+Normally, the cursor is displayed at the end of any overlay and text
+property strings present at the current window position.  You can
+place the cursor on any desired character of these strings by giving
+that character a address@hidden @var{cursor} text property.
+
address@hidden pointer
address@hidden pointer @r{(text property)}
+This specifies a specific pointer shape when the mouse pointer is over
+this text or image.  @xref{Pointer Shape}, for possible pointer
+shapes.
+
address@hidden line-spacing
address@hidden line-spacing @r{(text property)}
+A newline can have a @code{line-spacing} text or overlay property that
+controls the height of the display line ending with that newline.  The
+property value overrides the default frame line spacing and the buffer
+local @code{line-spacing} variable.  @xref{Line Height}.
+
address@hidden line-height
address@hidden line-height @r{(text property)}
+A newline can have a @code{line-height} text or overlay property that
+controls the total height of the display line ending in that newline.
address@hidden Height}.
+
address@hidden modification-hooks
address@hidden change hooks for a character
address@hidden hooks for changing a character
address@hidden modification-hooks @r{(text property)}
+If a character has the property @code{modification-hooks}, then its
+value should be a list of functions; modifying that character calls all
+of those functions.  Each function receives two arguments: the beginning
+and end of the part of the buffer being modified.  Note that if a
+particular modification hook function appears on several characters
+being modified by a single primitive, you can't predict how many times
+the function will be called.
+
+If these functions modify the buffer, they should bind
address@hidden to @code{t} around doing so, to
+avoid confusing the internal mechanism that calls these hooks.
+
+Overlays also support the @code{modification-hooks} property, but the
+details are somewhat different (@pxref{Overlay Properties}).
+
address@hidden insert-in-front-hooks
address@hidden insert-behind-hooks
address@hidden insert-in-front-hooks @r{(text property)}
address@hidden insert-behind-hooks @r{(text property)}
+The operation of inserting text in a buffer also calls the functions
+listed in the @code{insert-in-front-hooks} property of the following
+character and in the @code{insert-behind-hooks} property of the
+preceding character.  These functions receive two arguments, the
+beginning and end of the inserted text.  The functions are called
address@hidden the actual insertion takes place.
+
+See also @ref{Change Hooks}, for other hooks that are called
+when you change text in a buffer.
+
address@hidden point-entered
address@hidden point-left
address@hidden hooks for motion of point
address@hidden point-entered @r{(text property)}
address@hidden point-left @r{(text property)}
+The special properties @code{point-entered} and @code{point-left}
+record hook functions that report motion of point.  Each time point
+moves, Emacs compares these two property values:
+
address@hidden @bullet
address@hidden
+the @code{point-left} property of the character after the old location,
+and
address@hidden
+the @code{point-entered} property of the character after the new
+location.
address@hidden itemize
+
address@hidden
+If these two values differ, each of them is called (if not @code{nil})
+with two arguments: the old value of point, and the new one.
+
+The same comparison is made for the characters before the old and new
+locations.  The result may be to execute two @code{point-left} functions
+(which may be the same function) and/or two @code{point-entered}
+functions (which may be the same function).  In any case, all the
address@hidden functions are called first, followed by all the
address@hidden functions.
+
+It is possible with @code{char-after} to examine characters at various
+buffer positions without moving point to those positions.  Only an
+actual change in the value of point runs these hook functions.
+
address@hidden inhibit-point-motion-hooks
+When this variable is address@hidden, @code{point-left} and
address@hidden hooks are not run, and the @code{intangible}
+property has no effect.  Do not set this variable globally; bind it with
address@hidden
address@hidden defvar
+
address@hidden show-help-function
address@hidden display} If this variable is address@hidden, it specifies a
+function called to display help strings.  These may be @code{help-echo}
+properties, menu help strings (@pxref{Simple Menu Items},
address@hidden Menu Items}), or tool bar help strings (@pxref{Tool
+Bar}).  The specified function is called with one argument, the help
+string to display.  Tooltip mode (@pxref{Tooltips,,, emacs, The GNU Emacs
+Manual}) provides an example.
address@hidden defvar
+
address@hidden composition
address@hidden composition @r{(text property)}
+This text property is used to display a sequence of characters as a
+single glyph composed from components.  But the value of the property
+itself is completely internal to Emacs and should not be manipulated
+directly by, for instance, @code{put-text-property}.
+
address@hidden table
+
address@hidden Format Properties
address@hidden Formatted Text Properties
+
+  These text properties affect the behavior of the fill commands.  They
+are used for representing formatted text.  @xref{Filling}, and
address@hidden
+
address@hidden @code
address@hidden hard
+If a newline character has this property, it is a ``hard'' newline.
+The fill commands do not alter hard newlines and do not move words
+across them.  However, this property takes effect only if the
address@hidden minor mode is enabled.  @xref{Hard and Soft
+Newlines,, Hard and Soft Newlines, emacs, The GNU Emacs Manual}.
+
address@hidden right-margin
+This property specifies an extra right margin for filling this part of the
+text.
+
address@hidden left-margin
+This property specifies an extra left margin for filling this part of the
+text.
+
address@hidden justification
+This property specifies the style of justification for filling this part
+of the text.
address@hidden table
+
address@hidden Sticky Properties
address@hidden Stickiness of Text Properties
address@hidden sticky text properties
address@hidden inheritance of text properties
+
+  Self-inserting characters normally take on the same properties as the
+preceding character.  This is called @dfn{inheritance} of properties.
+
+  In a Lisp program, you can do insertion with inheritance or without,
+depending on your choice of insertion primitive.  The ordinary text
+insertion functions such as @code{insert} do not inherit any properties.
+They insert text with precisely the properties of the string being
+inserted, and no others.  This is correct for programs that copy text
+from one context to another---for example, into or out of the kill ring.
+To insert with inheritance, use the special primitives described in this
+section.  Self-inserting characters inherit properties because they work
+using these primitives.
+
+  When you do insertion with inheritance, @emph{which} properties are
+inherited, and from where, depends on which properties are @dfn{sticky}.
+Insertion after a character inherits those of its properties that are
address@hidden  Insertion before a character inherits those of its
+properties that are @dfn{front-sticky}.  When both sides offer different
+sticky values for the same property, the previous character's value
+takes precedence.
+
+  By default, a text property is rear-sticky but not front-sticky; thus,
+the default is to inherit all the properties of the preceding character,
+and nothing from the following character.
+
+  You can control the stickiness of various text properties with two
+specific text properties, @code{front-sticky} and @code{rear-nonsticky},
+and with the variable @code{text-property-default-nonsticky}.  You can
+use the variable to specify a different default for a given property.
+You can use those two text properties to make any specific properties
+sticky or nonsticky in any particular part of the text.
+
+  If a character's @code{front-sticky} property is @code{t}, then all
+its properties are front-sticky.  If the @code{front-sticky} property is
+a list, then the sticky properties of the character are those whose
+names are in the list.  For example, if a character has a
address@hidden property whose value is @code{(face read-only)},
+then insertion before the character can inherit its @code{face} property
+and its @code{read-only} property, but no others.
+
+  The @code{rear-nonsticky} property works the opposite way.  Most
+properties are rear-sticky by default, so the @code{rear-nonsticky}
+property says which properties are @emph{not} rear-sticky.  If a
+character's @code{rear-nonsticky} property is @code{t}, then none of its
+properties are rear-sticky.  If the @code{rear-nonsticky} property is a
+list, properties are rear-sticky @emph{unless} their names are in the
+list.
+
address@hidden text-property-default-nonsticky
+This variable holds an alist which defines the default rear-stickiness
+of various text properties.  Each element has the form
address@hidden(@var{property} . @var{nonstickiness})}, and it defines the
+stickiness of a particular text property, @var{property}.
+
+If @var{nonstickiness} is address@hidden, this means that the property
address@hidden is rear-nonsticky by default.  Since all properties are
+front-nonsticky by default, this makes @var{property} nonsticky in both
+directions by default.
+
+The text properties @code{front-sticky} and @code{rear-nonsticky}, when
+used, take precedence over the default @var{nonstickiness} specified in
address@hidden
address@hidden defvar
+
+  Here are the functions that insert text with inheritance of properties:
+
address@hidden insert-and-inherit &rest strings
+Insert the strings @var{strings}, just like the function @code{insert},
+but inherit any sticky properties from the adjoining text.
address@hidden defun
+
address@hidden insert-before-markers-and-inherit &rest strings
+Insert the strings @var{strings}, just like the function
address@hidden, but inherit any sticky properties from the
+adjoining text.
address@hidden defun
+
+  @xref{Insertion}, for the ordinary insertion functions which do not
+inherit.
+
address@hidden Lazy Properties
address@hidden Lazy Computation of Text Properties
+
+  Instead of computing text properties for all the text in the buffer,
+you can arrange to compute the text properties for parts of the text
+when and if something depends on them.
+
+  The primitive that extracts text from the buffer along with its
+properties is @code{buffer-substring}.  Before examining the properties,
+this function runs the abnormal hook @code{buffer-access-fontify-functions}.
+
address@hidden buffer-access-fontify-functions
+This variable holds a list of functions for computing text properties.
+Before @code{buffer-substring} copies the text and text properties for a
+portion of the buffer, it calls all the functions in this list.  Each of
+the functions receives two arguments that specify the range of the
+buffer being accessed.  (The buffer itself is always the current
+buffer.)
address@hidden defvar
+
+  The function @code{buffer-substring-no-properties} does not call these
+functions, since it ignores text properties anyway.
+
+  In order to prevent the hook functions from being called more than
+once for the same part of the buffer, you can use the variable
address@hidden
+
address@hidden buffer-access-fontified-property
+If this variable's value is address@hidden, it is a symbol which is used
+as a text property name.  A address@hidden value for that text property
+means, ``the other text properties for this character have already been
+computed.''
+
+If all the characters in the range specified for @code{buffer-substring}
+have a address@hidden value for this property, @code{buffer-substring}
+does not call the @code{buffer-access-fontify-functions} functions.  It
+assumes these characters already have the right text properties, and
+just copies the properties they already have.
+
+The normal way to use this feature is that the
address@hidden functions add this property, as
+well as others, to the characters they operate on.  That way, they avoid
+being called over and over for the same text.
address@hidden defvar
+
address@hidden Clickable Text
address@hidden Defining Clickable Text
address@hidden clickable text
+
+  @dfn{Clickable text} is text that can be clicked, with either the
+the mouse or via keyboard commands, to produce some result.  Many
+major modes use clickable text to implement features such as
+hyper-links.  The @code{button} package provides an easy way to insert
+and manipulate clickable text.  @xref{Buttons}.
+
+  In this section, we will explain how to manually set up clickable
+text in a buffer using text properties.  This involves two things: (1)
+indicating clickability when the mouse moves over the text, and (2)
+making @kbd{RET} or a mouse click on that text do something.
+
+  Indicating clickability usually involves highlighting the text, and
+often involves displaying helpful information about the action, such
+as which mouse button to press, or a short summary of the action.
+This can be done with the @code{mouse-face} and @code{help-echo}
+text properties.  @xref{Special Properties}.
+Here is an example of how Dired does it:
+
address@hidden
+(condition-case nil
+    (if (dired-move-to-filename)
+        (add-text-properties
+         (point)
+         (save-excursion
+           (dired-move-to-end-of-filename)
+           (point))
+         '(mouse-face highlight
+           help-echo "mouse-2: visit this file in other window")))
+  (error nil))
address@hidden smallexample
+
address@hidden
+The first two arguments to @code{add-text-properties} specify the
+beginning and end of the text.
+
+  The usual way to make the mouse do something when you click it
+on this text is to define @code{mouse-2} in the major mode's
+keymap.  The job of checking whether the click was on clickable text
+is done by the command definition.  Here is how Dired does it:
+
address@hidden
+(defun dired-mouse-find-file-other-window (event)
+  "In Dired, visit the file or directory name you click on."
+  (interactive "e")
+  (let (window pos file)
+    (save-excursion
+      (setq window (posn-window (event-end event))
+            pos (posn-point (event-end event)))
+      (if (not (windowp window))
+          (error "No file chosen"))
+      (set-buffer (window-buffer window))
+      (goto-char pos)
+      (setq file (dired-get-file-for-visit)))
+    (if (file-directory-p file)
+        (or (and (cdr dired-subdir-alist)
+                 (dired-goto-subdir file))
+            (progn
+              (select-window window)
+              (dired-other-window file)))
+      (select-window window)
+      (find-file-other-window (file-name-sans-versions file t)))))
address@hidden smallexample
+
address@hidden
+The reason for the @code{save-excursion} construct is to avoid
+changing the current buffer.  In this case,
+Dired uses the functions @code{posn-window} and @code{posn-point}
+to determine which buffer the click happened in and where, and
+in that buffer, @code{dired-get-file-for-visit} to determine which
+file to visit.
+
+  Instead of defining a mouse command for the major mode, you can define
+a key binding for the clickable text itself, using the @code{keymap}
+text property:
+
address@hidden
+(let ((map (make-sparse-keymap)))
+  (define-key map [mouse-2] 'operate-this-button)
+  (put-text-property (point)
+                     (save-excursion
+                       (dired-move-to-end-of-filename)
+                       (point))
+                     'keymap map))
address@hidden example
+
address@hidden
+This method makes it possible to define different commands for various
+clickable pieces of text.  Also, the major mode definition (or the
+global definition) remains available for the rest of the text in the
+buffer.
+
address@hidden Links and Mouse-1
address@hidden Links and Mouse-1
address@hidden follow links
address@hidden mouse-1
+
+  The normal Emacs command for activating text in read-only buffers is
address@hidden, which includes following textual links.  However, most
+graphical applications use @key{Mouse-1} for following links.  For
+compatibility, @key{Mouse-1} follows links in Emacs too, when you
+click on a link quickly without moving the mouse.  The user can
+customize this behavior through the variable
address@hidden
+
+  To define text as a link at the Lisp level, you should bind the
address@hidden event to a command to follow the link.  Then, to indicate that
address@hidden should also follow the link, you should specify a
address@hidden condition either as a text property or as a key
+binding:
+
address@hidden @asis
address@hidden @code{follow-link} property
+If the clickable text has a address@hidden @code{follow-link} text or overlay
+property, that specifies the condition.
+
address@hidden @code{follow-link} event
+If there is a binding for the @code{follow-link} event, either on the
+clickable text or in the local keymap, the binding is the condition.
address@hidden table
+
+  Regardless of how you set the @code{follow-link} condition, its
+value is used as follows to determine whether the given position is
+inside a link, and (if so) to compute an @dfn{action code} saying how
address@hidden should handle the link.
+
address@hidden @asis
address@hidden @code{mouse-face}
+If the condition is @code{mouse-face}, a position is inside a link if
+there is a address@hidden @code{mouse-face} property at that position.
+The action code is always @code{t}.
+
+For example, here is how Info mode handles @key{Mouse-1}:
+
address@hidden
+(define-key Info-mode-map [follow-link] 'mouse-face)
address@hidden smallexample
+
address@hidden a function
+If the condition is a valid function, @var{func}, then a position
address@hidden is inside a link if @code{(@var{func} @var{pos})} evaluates
+to address@hidden  The value returned by @var{func} serves as the
+action code.
+
+For example, here is how pcvs enables @key{Mouse-1} to follow links on
+file names only:
+
address@hidden
+(define-key map [follow-link]
+  (lambda (pos)
+    (eq (get-char-property pos 'face) 'cvs-filename-face)))
address@hidden smallexample
+
address@hidden anything else
+If the condition value is anything else, then the position is inside a
+link and the condition itself is the action code.  Clearly you should
+only specify this kind of condition on the text that constitutes a
+link.
address@hidden table
+
address@hidden
+The action code tells @key{Mouse-1} how to follow the link:
+
address@hidden @asis
address@hidden a string or vector
+If the action code is a string or vector, the @key{Mouse-1} event is
+translated into the first element of the string or vector; i.e., the
+action of the @key{Mouse-1} click is the local or global binding of
+that character or symbol.  Thus, if the action code is @code{"foo"},
address@hidden translates into @kbd{f}.  If it is @code{[foo]},
address@hidden translates into @key{foo}.
+
address@hidden anything else
+For any other address@hidden action code, the @code{mouse-1} event is
+translated into a @code{mouse-2} event at the same position.
address@hidden table
+
+  To define @key{Mouse-1} to activate a button defined with
address@hidden, give the button a @code{follow-link}
+property with a value as specified above to determine how to follow
+the link.  For example, here is how Help mode handles @key{Mouse-1}:
+
address@hidden
+(define-button-type 'help-xref
+  'follow-link t
+  'action #'help-button-action)
address@hidden smallexample
+
+  To define @key{Mouse-1} on a widget defined with
address@hidden, give the widget a @code{:follow-link} property
+with a value as specified above to determine how to follow the link.
+
+For example, here is how the @code{link} widget specifies that
+a @key{Mouse-1} click shall be translated to @key{RET}:
+
address@hidden
+(define-widget 'link 'item
+  "An embedded link."
+  :button-prefix 'widget-link-prefix
+  :button-suffix 'widget-link-suffix
+  :follow-link "\C-m"
+  :help-echo "Follow the link."
+  :format "%[%t%]")
address@hidden smallexample
+
address@hidden mouse-on-link-p pos
+This function returns address@hidden if position @var{pos} in the
+current buffer is on a link.  @var{pos} can also be a mouse event
+location, as returned by @code{event-start} (@pxref{Accessing Events}).
address@hidden defun
+
address@hidden Fields
address@hidden Defining and Using Fields
address@hidden fields
+
+  A field is a range of consecutive characters in the buffer that are
+identified by having the same value (comparing with @code{eq}) of the
address@hidden property (either a text-property or an overlay property).
+This section describes special functions that are available for
+operating on fields.
+
+  You specify a field with a buffer position, @var{pos}.  We think of
+each field as containing a range of buffer positions, so the position
+you specify stands for the field containing that position.
+
+  When the characters before and after @var{pos} are part of the same
+field, there is no doubt which field contains @var{pos}: the one those
+characters both belong to.  When @var{pos} is at a boundary between
+fields, which field it belongs to depends on the stickiness of the
address@hidden properties of the two surrounding characters (@pxref{Sticky
+Properties}).  The field whose property would be inherited by text
+inserted at @var{pos} is the field that contains @var{pos}.
+
+  There is an anomalous case where newly inserted text at @var{pos}
+would not inherit the @code{field} property from either side.  This
+happens if the previous character's @code{field} property is not
+rear-sticky, and the following character's @code{field} property is not
+front-sticky.  In this case, @var{pos} belongs to neither the preceding
+field nor the following field; the field functions treat it as belonging
+to an empty field whose beginning and end are both at @var{pos}.
+
+  In all of these functions, if @var{pos} is omitted or @code{nil}, the
+value of point is used by default.  If narrowing is in effect, then
address@hidden should fall within the accessible portion.  @xref{Narrowing}.
+
address@hidden field-beginning &optional pos escape-from-edge limit
+This function returns the beginning of the field specified by @var{pos}.
+
+If @var{pos} is at the beginning of its field, and
address@hidden is address@hidden, then the return value is
+always the beginning of the preceding field that @emph{ends} at @var{pos},
+regardless of the stickiness of the @code{field} properties around
address@hidden
+
+If @var{limit} is address@hidden, it is a buffer position; if the
+beginning of the field is before @var{limit}, then @var{limit} will be
+returned instead.
address@hidden defun
+
address@hidden field-end &optional pos escape-from-edge limit
+This function returns the end of the field specified by @var{pos}.
+
+If @var{pos} is at the end of its field, and @var{escape-from-edge} is
address@hidden, then the return value is always the end of the following
+field that @emph{begins} at @var{pos}, regardless of the stickiness of
+the @code{field} properties around @var{pos}.
+
+If @var{limit} is address@hidden, it is a buffer position; if the end
+of the field is after @var{limit}, then @var{limit} will be returned
+instead.
address@hidden defun
+
address@hidden field-string &optional pos
+This function returns the contents of the field specified by @var{pos},
+as a string.
address@hidden defun
+
address@hidden field-string-no-properties &optional pos
+This function returns the contents of the field specified by @var{pos},
+as a string, discarding text properties.
address@hidden defun
+
address@hidden delete-field &optional pos
+This function deletes the text of the field specified by @var{pos}.
address@hidden defun
+
address@hidden constrain-to-field new-pos old-pos &optional escape-from-edge 
only-in-line inhibit-capture-property
+This function ``constrains'' @var{new-pos} to the field that
address@hidden belongs to---in other words, it returns the position
+closest to @var{new-pos} that is in the same field as @var{old-pos}.
+
+If @var{new-pos} is @code{nil}, then @code{constrain-to-field} uses
+the value of point instead, and moves point to the resulting position
+as well as returning it.
+
+If @var{old-pos} is at the boundary of two fields, then the acceptable
+final positions depend on the argument @var{escape-from-edge}.  If
address@hidden is @code{nil}, then @var{new-pos} must be in
+the field whose @code{field} property equals what new characters
+inserted at @var{old-pos} would inherit.  (This depends on the
+stickiness of the @code{field} property for the characters before and
+after @var{old-pos}.)  If @var{escape-from-edge} is address@hidden,
address@hidden can be anywhere in the two adjacent fields.
+Additionally, if two fields are separated by another field with the
+special value @code{boundary}, then any point within this special
+field is also considered to be ``on the boundary.''
+
+Commands like @kbd{C-a} with no argumemt, that normally move backward
+to a specific kind of location and stay there once there, probably
+should specify @code{nil} for @var{escape-from-edge}.  Other motion
+commands that check fields should probably pass @code{t}.
+
+If the optional argument @var{only-in-line} is address@hidden, and
+constraining @var{new-pos} in the usual way would move it to a different
+line, @var{new-pos} is returned unconstrained.  This used in commands
+that move by line, such as @code{next-line} and
address@hidden, so that they respect field boundaries only in
+the case where they can still move to the right line.
+
+If the optional argument @var{inhibit-capture-property} is
address@hidden, and @var{old-pos} has a address@hidden property of that
+name, then any field boundaries are ignored.
+
+You can cause @code{constrain-to-field} to ignore all field boundaries
+(and so never constrain anything) by binding the variable
address@hidden to a address@hidden value.
address@hidden defun
+
address@hidden Not Intervals
address@hidden Why Text Properties are not Intervals
address@hidden intervals
+
+  Some editors that support adding attributes to text in the buffer do
+so by letting the user specify ``intervals'' within the text, and adding
+the properties to the intervals.  Those editors permit the user or the
+programmer to determine where individual intervals start and end.  We
+deliberately provided a different sort of interface in Emacs Lisp to
+avoid certain paradoxical behavior associated with text modification.
+
+  If the actual subdivision into intervals is meaningful, that means you
+can distinguish between a buffer that is just one interval with a
+certain property, and a buffer containing the same text subdivided into
+two intervals, both of which have that property.
+
+  Suppose you take the buffer with just one interval and kill part of
+the text.  The text remaining in the buffer is one interval, and the
+copy in the kill ring (and the undo list) becomes a separate interval.
+Then if you yank back the killed text, you get two intervals with the
+same properties.  Thus, editing does not preserve the distinction
+between one interval and two.
+
+  Suppose we ``fix'' this problem by coalescing the two intervals when
+the text is inserted.  That works fine if the buffer originally was a
+single interval.  But suppose instead that we have two adjacent
+intervals with the same properties, and we kill the text of one interval
+and yank it back.  The same interval-coalescence feature that rescues
+the other case causes trouble in this one: after yanking, we have just
+one interval.  One again, editing does not preserve the distinction
+between one interval and two.
+
+  Insertion of text at the border between intervals also raises
+questions that have no satisfactory answer.
+
+  However, it is easy to arrange for editing to behave consistently for
+questions of the form, ``What are the properties of this character?''
+So we have decided these are the only questions that make sense; we have
+not implemented asking questions about where intervals start or end.
+
+  In practice, you can usually use the text property search functions in
+place of explicit interval boundaries.  You can think of them as finding
+the boundaries of intervals, assuming that intervals are always
+coalesced whenever possible.  @xref{Property Search}.
+
+  Emacs also provides explicit intervals as a presentation feature; see
address@hidden
+
address@hidden Substitution
address@hidden Substituting for a Character Code
+
+  The following functions replace characters within a specified region
+based on their character codes.
+
address@hidden subst-char-in-region start end old-char new-char &optional noundo
address@hidden replace characters
+This function replaces all occurrences of the character @var{old-char}
+with the character @var{new-char} in the region of the current buffer
+defined by @var{start} and @var{end}.
+
address@hidden undo avoidance
+If @var{noundo} is address@hidden, then @code{subst-char-in-region} does
+not record the change for undo and does not mark the buffer as modified.
+This was useful for controlling the old selective display feature
+(@pxref{Selective Display}).
+
address@hidden does not move point and returns
address@hidden
+
address@hidden
address@hidden
+---------- Buffer: foo ----------
+This is the contents of the buffer before.
+---------- Buffer: foo ----------
address@hidden group
+
address@hidden
+(subst-char-in-region 1 20 ?i ?X)
+     @result{} nil
+
+---------- Buffer: foo ----------
+ThXs Xs the contents of the buffer before.
+---------- Buffer: foo ----------
address@hidden group
address@hidden example
address@hidden defun
+
address@hidden translate-region start end table
+This function applies a translation table to the characters in the
+buffer between positions @var{start} and @var{end}.
+
+The translation table @var{table} is a string or a char-table;
address@hidden(aref @var{table} @var{ochar})} gives the translated character
+corresponding to @var{ochar}.  If @var{table} is a string, any
+characters with codes larger than the length of @var{table} are not
+altered by the translation.
+
+The return value of @code{translate-region} is the number of
+characters that were actually changed by the translation.  This does
+not count characters that were mapped into themselves in the
+translation table.
address@hidden defun
+
address@hidden Registers
address@hidden Registers
address@hidden registers
+
+  A register is a sort of variable used in Emacs editing that can hold a
+variety of different kinds of values.  Each register is named by a
+single character.  All @acronym{ASCII} characters and their meta variants
+(but with the exception of @kbd{C-g}) can be used to name registers.
+Thus, there are 255 possible registers.  A register is designated in
+Emacs Lisp by the character that is its name.
+
address@hidden register-alist
+This variable is an alist of elements of the form @code{(@var{name} .
address@hidden)}.  Normally, there is one element for each Emacs
+register that has been used.
+
+The object @var{name} is a character (an integer) identifying the
+register.
address@hidden defvar
+
+  The @var{contents} of a register can have several possible types:
+
address@hidden @asis
address@hidden a number
+A number stands for itself.  If @code{insert-register} finds a number
+in the register, it converts the number to decimal.
+
address@hidden a marker
+A marker represents a buffer position to jump to.
+
address@hidden a string
+A string is text saved in the register.
+
address@hidden a rectangle
+A rectangle is represented by a list of strings.
+
address@hidden @code{(@var{window-configuration} @var{position})}
+This represents a window configuration to restore in one frame, and a
+position to jump to in the current buffer.
+
address@hidden @code{(@var{frame-configuration} @var{position})}
+This represents a frame configuration to restore, and a position
+to jump to in the current buffer.
+
address@hidden (file @var{filename})
+This represents a file to visit; jumping to this value visits file
address@hidden
+
address@hidden (file-query @var{filename} @var{position})
+This represents a file to visit and a position in it; jumping to this
+value visits file @var{filename} and goes to buffer position
address@hidden  Restoring this type of position asks the user for
+confirmation first.
address@hidden table
+
+  The functions in this section return unpredictable values unless
+otherwise stated.
+
address@hidden get-register reg
+This function returns the contents of the register
address@hidden, or @code{nil} if it has no contents.
address@hidden defun
+
address@hidden set-register reg value
+This function sets the contents of register @var{reg} to @var{value}.
+A register can be set to any value, but the other register functions
+expect only certain data types.  The return value is @var{value}.
address@hidden defun
+
address@hidden Command view-register reg
+This command displays what is contained in register @var{reg}.
address@hidden deffn
+
address@hidden
address@hidden Command point-to-register reg
+This command stores both the current location of point and the current
+buffer in register @var{reg} as a marker.
address@hidden deffn
+
address@hidden Command jump-to-register reg
address@hidden Command register-to-point reg
address@hidden !!SourceFile register.el
+This command restores the status recorded in register @var{reg}.
+
+If @var{reg} contains a marker, it moves point to the position stored in
+the marker.  Since both the buffer and the location within the buffer
+are stored by the @code{point-to-register} function, this command can
+switch you to another buffer.
+
+If @var{reg} contains a window configuration or a frame configuration.
address@hidden restores that configuration.
address@hidden deffn
address@hidden ignore
+
address@hidden Command insert-register reg &optional beforep
+This command inserts contents of register @var{reg} into the current
+buffer.
+
+Normally, this command puts point before the inserted text, and the
+mark after it.  However, if the optional second argument @var{beforep}
+is address@hidden, it puts the mark before and point after.
+You can pass a address@hidden second argument @var{beforep} to this
+function interactively by supplying any prefix argument.
+
+If the register contains a rectangle, then the rectangle is inserted
+with its upper left corner at point.  This means that text is inserted
+in the current line and underneath it on successive lines.
+
+If the register contains something other than saved text (a string) or
+a rectangle (a list), currently useless things happen.  This may be
+changed in the future.
address@hidden deffn
+
address@hidden
address@hidden Command copy-to-register reg start end &optional delete-flag
+This command copies the region from @var{start} to @var{end} into
+register @var{reg}.  If @var{delete-flag} is address@hidden, it deletes
+the region from the buffer after copying it into the register.
address@hidden deffn
+
address@hidden Command prepend-to-register reg start end &optional delete-flag
+This command prepends the region from @var{start} to @var{end} into
+register @var{reg}.  If @var{delete-flag} is address@hidden, it deletes
+the region from the buffer after copying it to the register.
address@hidden deffn
+
address@hidden Command append-to-register reg start end &optional delete-flag
+This command appends the region from @var{start} to @var{end} to the
+text already in register @var{reg}.  If @var{delete-flag} is
address@hidden, it deletes the region from the buffer after copying it
+to the register.
address@hidden deffn
+
address@hidden Command copy-rectangle-to-register reg start end &optional 
delete-flag
+This command copies a rectangular region from @var{start} to @var{end}
+into register @var{reg}.  If @var{delete-flag} is address@hidden, it
+deletes the region from the buffer after copying it to the register.
address@hidden deffn
+
address@hidden Command window-configuration-to-register reg
+This function stores the window configuration of the selected frame in
+register @var{reg}.
address@hidden deffn
+
address@hidden Command frame-configuration-to-register reg
+This function stores the current frame configuration in register
address@hidden
address@hidden deffn
address@hidden ignore
+
address@hidden Transposition
address@hidden Transposition of Text
+
+  This subroutine is used by the transposition commands.
+
address@hidden transpose-regions start1 end1 start2 end2 &optional leave-markers
+This function exchanges two nonoverlapping portions of the buffer.
+Arguments @var{start1} and @var{end1} specify the bounds of one portion
+and arguments @var{start2} and @var{end2} specify the bounds of the
+other portion.
+
+Normally, @code{transpose-regions} relocates markers with the transposed
+text; a marker previously positioned within one of the two transposed
+portions moves along with that portion, thus remaining between the same
+two characters in their new position.  However, if @var{leave-markers}
+is address@hidden, @code{transpose-regions} does not do this---it leaves
+all markers unrelocated.
address@hidden defun
+
address@hidden Base 64
address@hidden Base 64 Encoding
address@hidden base 64 encoding
+
+  Base 64 code is used in email to encode a sequence of 8-bit bytes as
+a longer sequence of @acronym{ASCII} graphic characters.  It is defined in
+Internet address@hidden
+An RFC, an acronym for @dfn{Request for Comments}, is a numbered
+Internet informational document describing a standard.  RFCs are
+usually written by technical experts acting on their own initiative,
+and are traditionally written in a pragmatic, experience-driven
+manner.
+}2045.  This section describes the functions for
+converting to and from this code.
+
address@hidden base64-encode-region beg end &optional no-line-break
+This function converts the region from @var{beg} to @var{end} into base
+64 code.  It returns the length of the encoded text.  An error is
+signaled if a character in the region is multibyte, i.e.@: in a
+multibyte buffer the region must contain only characters from the
+charsets @code{ascii}, @code{eight-bit-control} and
address@hidden
+
+Normally, this function inserts newline characters into the encoded
+text, to avoid overlong lines.  However, if the optional argument
address@hidden is address@hidden, these newlines are not added, so
+the output is just one long line.
address@hidden defun
+
address@hidden base64-encode-string string &optional no-line-break
+This function converts the string @var{string} into base 64 code.  It
+returns a string containing the encoded text.  As for
address@hidden, an error is signaled if a character in the
+string is multibyte.
+
+Normally, this function inserts newline characters into the encoded
+text, to avoid overlong lines.  However, if the optional argument
address@hidden is address@hidden, these newlines are not added, so
+the result string is just one long line.
address@hidden defun
+
address@hidden base64-decode-region beg end
+This function converts the region from @var{beg} to @var{end} from base
+64 code into the corresponding decoded text.  It returns the length of
+the decoded text.
+
+The decoding functions ignore newline characters in the encoded text.
address@hidden defun
+
address@hidden base64-decode-string string
+This function converts the string @var{string} from base 64 code into
+the corresponding decoded text.  It returns a unibyte string containing the
+decoded text.
+
+The decoding functions ignore newline characters in the encoded text.
address@hidden defun
+
address@hidden MD5 Checksum
address@hidden MD5 Checksum
address@hidden MD5 checksum
address@hidden message digest computation
+
+  MD5 cryptographic checksums, or @dfn{message digests}, are 128-bit
+``fingerprints'' of a document or program.  They are used to verify
+that you have an exact and unaltered copy of the data.  The algorithm
+to calculate the MD5 message digest is defined in Internet
address@hidden
+For an explanation of what is an RFC, see the footnote in @ref{Base
+64}.
+}1321.  This section describes the Emacs facilities for computing
+message digests.
+
address@hidden md5 object &optional start end coding-system noerror
+This function returns the MD5 message digest of @var{object}, which
+should be a buffer or a string.
+
+The two optional arguments @var{start} and @var{end} are character
+positions specifying the portion of @var{object} to compute the
+message digest for.  If they are @code{nil} or omitted, the digest is
+computed for the whole of @var{object}.
+
+The function @code{md5} does not compute the message digest directly
+from the internal Emacs representation of the text (@pxref{Text
+Representations}).  Instead, it encodes the text using a coding
+system, and computes the message digest from the encoded text.  The
+optional fourth argument @var{coding-system} specifies which coding
+system to use for encoding the text.  It should be the same coding
+system that you used to read the text, or that you used or will use
+when saving or sending the text.  @xref{Coding Systems}, for more
+information about coding systems.
+
+If @var{coding-system} is @code{nil} or omitted, the default depends
+on @var{object}.  If @var{object} is a buffer, the default for
address@hidden is whatever coding system would be chosen by
+default for writing this text into a file.  If @var{object} is a
+string, the user's most preferred coding system (@pxref{Recognize
+Coding, prefer-coding-system, the description of
address@hidden, emacs, GNU Emacs Manual}) is used.
+
+Normally, @code{md5} signals an error if the text can't be encoded
+using the specified or chosen coding system.  However, if
address@hidden is address@hidden, it silently uses @code{raw-text}
+coding instead.
address@hidden defun
+
address@hidden Atomic Changes
address@hidden Atomic Change Groups
address@hidden atomic changes
+
+  In data base terminology, an @dfn{atomic} change is an indivisible
+change---it can succeed entirely or it can fail entirely, but it
+cannot partly succeed.  A Lisp program can make a series of changes to
+one or several buffers as an @dfn{atomic change group}, meaning that
+either the entire series of changes will be installed in their buffers
+or, in case of an error, none of them will be.
+
+  To do this for one buffer, the one already current, simply write a
+call to @code{atomic-change-group} around the code that makes the
+changes, like this:
+
address@hidden
+(atomic-change-group
+  (insert foo)
+  (delete-region x y))
address@hidden example
+
address@hidden
+If an error (or other nonlocal exit) occurs inside the body of
address@hidden, it unmakes all the changes in that buffer
+that were during the execution of the body.  This kind of change group
+has no effect on any other buffers---any such changes remain.
+
+  If you need something more sophisticated, such as to make changes in
+various buffers constitute one atomic group, you must directly call
+lower-level functions that @code{atomic-change-group} uses.
+
address@hidden prepare-change-group &optional buffer
+This function sets up a change group for buffer @var{buffer}, which
+defaults to the current buffer.  It returns a ``handle'' that
+represents the change group.  You must use this handle to activate the
+change group and subsequently to finish it.
address@hidden defun
+
+  To use the change group, you must @dfn{activate} it.  You must do
+this before making any changes in the text of @var{buffer}.
+
address@hidden activate-change-group handle
+This function activates the change group that @var{handle} designates.
address@hidden defun
+
+  After you activate the change group, any changes you make in that
+buffer become part of it.  Once you have made all the desired changes
+in the buffer, you must @dfn{finish} the change group.  There are two
+ways to do this: you can either accept (and finalize) all the changes,
+or cancel them all.
+
address@hidden accept-change-group handle
+This function accepts all the changes in the change group specified by
address@hidden, making them final.
address@hidden defun
+
address@hidden cancel-change-group handle
+This function cancels and undoes all the changes in the change group
+specified by @var{handle}.
address@hidden defun
+
+  Your code should use @code{unwind-protect} to make sure the group is
+always finished.  The call to @code{activate-change-group} should be
+inside the @code{unwind-protect}, in case the user types @kbd{C-g}
+just after it runs.  (This is one reason why
address@hidden and @code{activate-change-group} are
+separate functions, because normally you would call
address@hidden before the start of that
address@hidden)  Once you finish the group, don't use the
+handle again---in particular, don't try to finish the same group
+twice.
+
+  To make a multibuffer change group, call @code{prepare-change-group}
+once for each buffer you want to cover, then use @code{nconc} to
+combine the returned values, like this:
+
address@hidden
+(nconc (prepare-change-group buffer-1)
+       (prepare-change-group buffer-2))
address@hidden example
+
+You can then activate the multibuffer change group with a single call
+to @code{activate-change-group}, and finish it with a single call to
address@hidden or @code{cancel-change-group}.
+
+  Nested use of several change groups for the same buffer works as you
+would expect.  Non-nested use of change groups for the same buffer
+will get Emacs confused, so don't let it happen; the first change
+group you start for any given buffer should be the last one finished.
+
address@hidden Change Hooks
address@hidden Change Hooks
address@hidden change hooks
address@hidden hooks for text changes
+
+  These hook variables let you arrange to take notice of all changes in
+all buffers (or in a particular buffer, if you make them buffer-local).
+See also @ref{Special Properties}, for how to detect changes to specific
+parts of the text.
+
+  The functions you use in these hooks should save and restore the match
+data if they do anything that uses regular expressions; otherwise, they
+will interfere in bizarre ways with the editing operations that call
+them.
+
address@hidden before-change-functions
+This variable holds a list of functions to call before any buffer
+modification.  Each function gets two arguments, the beginning and end
+of the region that is about to change, represented as integers.  The
+buffer that is about to change is always the current buffer.
address@hidden defvar
+
address@hidden after-change-functions
+This variable holds a list of functions to call after any buffer
+modification.  Each function receives three arguments: the beginning and
+end of the region just changed, and the length of the text that existed
+before the change.  All three arguments are integers.  The buffer that's
+about to change is always the current buffer.
+
+The length of the old text is the difference between the buffer positions
+before and after that text as it was before the change.  As for the
+changed text, its length is simply the difference between the first two
+arguments.
address@hidden defvar
+
+  Output of messages into the @samp{*Messages*} buffer does not
+call these functions.
+
address@hidden combine-after-change-calls address@hidden
+The macro executes @var{body} normally, but arranges to call the
+after-change functions just once for a series of several changes---if
+that seems safe.
+
+If a program makes several text changes in the same area of the buffer,
+using the macro @code{combine-after-change-calls} around that part of
+the program can make it run considerably faster when after-change hooks
+are in use.  When the after-change hooks are ultimately called, the
+arguments specify a portion of the buffer including all of the changes
+made within the @code{combine-after-change-calls} body.
+
address@hidden:} You must not alter the values of
address@hidden within
+the body of a @code{combine-after-change-calls} form.
+
address@hidden:} if the changes you combine occur in widely scattered
+parts of the buffer, this will still work, but it is not advisable,
+because it may lead to inefficient behavior for some change hook
+functions.
address@hidden defmac
+
address@hidden first-change-hook
+This variable is a normal hook that is run whenever a buffer is changed
+that was previously in the unmodified state.
address@hidden defvar
+
address@hidden inhibit-modification-hooks
+If this variable is address@hidden, all of the change hooks are
+disabled; none of them run.  This affects all the hook variables
+described above in this section, as well as the hooks attached to
+certain special text properties (@pxref{Special Properties}) and overlay
+properties (@pxref{Overlay Properties}).
+
+Also, this variable is bound to address@hidden while running those
+same hook variables, so that by default modifying the buffer from
+a modification hook does not cause other modification hooks to be run.
+If you do want modification hooks to be run in a particular piece of
+code that is itself run from a modification hook, then rebind locally
address@hidden to @code{nil}.
address@hidden defvar
+
address@hidden
+   arch-tag: 3721e738-a1cb-4085-bc1a-6cb8d8e1d32b
address@hidden ignore