@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
-@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2000, 2001
+@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999,
+@c 2000, 2001, 2004
@c Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@setfilename ../info/text
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 changs ``atomically''.
+* Atomic Changes:: Installing several buffer changes ``atomically''.
* Change Hooks:: Supplying functions to be run when text is changed.
@end menu
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.
+
@defun 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
@node Buffer Contents
@section Examining Buffer Contents
- This section describes two functions that allow a Lisp program to
+ This section describes functions that allow a Lisp program to
convert any portion of the text in the buffer into a string.
@defun buffer-substring start end
This function returns the symbol (or word) at or near point, as a string.
The return value includes no text properties.
-The optional argument @var{really-word} is non-@code{nil}, it finds a
-word; otherwise, it finds a symbol (which includes word characters and
-both symbol constituent characters).
+If the optional argument @var{really-word} is non-@code{nil}, 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 non-@code{nil}, then point
must be in or next to the symbol or word---if no symbol or word is
@defun 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 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.
+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
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 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.
+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.
@end defun
@defun 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 a
-number (@code{nil} means 1), and @var{character} must be a character.
-The value is @code{nil}.
+number, 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
@defun 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 from @var{start} and @var{end}. (These
+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}.
programs.
@deffn Command insert-buffer from-buffer-or-name
-This command inserts the entire contents of @var{from-buffer-or-name}
-(which must exist) into the current buffer after point. It leaves
-the mark after the inserted text. The value is @code{nil}.
+This command inserts the entire accessible contents of
+@var{from-buffer-or-name} (which must exist) into the current buffer
+after point. It leaves the mark after the inserted text. The value
+is @code{nil}.
@end deffn
@deffn Command self-insert-command count
Some deletion functions do save text in the kill ring in some special
cases.
- All of the deletion functions operate on the current buffer, and all
-return a value of @code{nil}.
+ All of the deletion functions operate on the current buffer.
@deffn Command erase-buffer
-This function deletes the entire text of the current buffer, leaving it
+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
@code{text-read-only} error. Otherwise, it deletes the text without
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;
-@code{hungry}, meaning delete all the whitespace characters before point
-with one command, and @code{nil}, meaning do nothing special for
+@code{hungry}, 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.
@end defopt
commands intended primarily for the user but useful also in Lisp
programs.
-@deffn Command delete-horizontal-space
+@deffn Command delete-horizontal-space &optional backward-only
@cindex deleting whitespace
This function deletes all spaces and tabs around point. It returns
@code{nil}.
+If @var{backward-only} is non-@code{nil}, 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.
responsible for deciding whether to leave a space at the junction.
@end deffn
-@defun fixup-whitespace
-This function replaces all the whitespace surrounding point with either
-one space or no space, according to the context. It returns @code{nil}.
+@deffn 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
---------- Buffer: foo ----------
@end group
@end smallexample
-@end defun
+@end deffn
-@deffn Command just-one-space
+@deffn Command just-one-space &optional n
@comment !!SourceFile simple.el
This command replaces any spaces and tabs around point with a single
-space. It returns @code{nil}.
+space, or @var{n} spaces if @var{n} is specified. It returns
+@code{nil}.
@end deffn
@deffn Command delete-blank-lines
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 following it.
+blank lines immediately following it.
A blank line is defined as a line containing only tabs and spaces.
* 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.
+* Internals of Kill Ring:: Variables that hold kill ring data.
@end menu
@node Kill Ring Concepts
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
+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.
commands to copy text from a read-only buffer into the kill ring.
If @var{yank-handler} is non-@code{nil}, this puts that value onto
-the string of killed text, as a @code{yank-handler} property.
-@xref{Yanking}.
+the string of killed text, as a @code{yank-handler} text property.
+@xref{Yanking}. Note that if @var{yank-handler} is @code{nil}, any
+@code{yank-handler} properties present on the killed text are copied
+onto the kill ring, like other text properties.
@end deffn
@defopt kill-read-only-ok
@deffn 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}. It also indicates the extent
-of the text copied by moving the cursor momentarily, or by displaying a
-message in the echo area.
+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.
@defun 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 the first character of @var{string} has a
-non-@code{nil}@code{yank-handler} text property, that property
-can do various special processing on the text being inserted.
+list. However, if any part of @var{string} has a non-@code{nil}
+@code{yank-handler} text property, that property can do various
+special processing on that part of the text being inserted.
@end defun
@defun insert-buffer-substring-as-yank buf &optional start end
@code{yank-excluded-properties} list.
@end defun
- You can put a @code{yank-handler} text property on the text to
-control how it will be inserted if it is yanked. The
-@code{insert-for-yank} function looks for a @code{yank-handler}
-property on the first character in its @var{string} argument. The
-property value must be a list of one to four elements, with the
-following format (where elements after the first may be omitted):
+ 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
+@code{insert-for-yank} 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):
@example
(@var{function} @var{param} @var{noexclude} @var{undo})
@table @var
@item function
-When @var{function} is present and non-nil, it is called instead of
+When @var{function} is present and non-@code{nil}, it is called instead of
@code{insert} to insert the string. @var{function} takes one
argument---the string to insert.
@item param
If @var{param} is present and non-@code{nil}, it replaces @var{string}
-as the object passed to @var{function} (or @code{insert}); for
-example, if @var{function} is @code{yank-rectangle}, @var{param}
-should be a list of strings to insert as a rectangle.
+(or the part of @var{string} being processed) as the object passed to
+@var{function} (or @code{insert}); for example, if @var{function} is
+@code{yank-rectangle}, @var{param} should be a list of strings to
+insert as a rectangle.
@item noexclude
If @var{noexclude} is present and non-@code{nil}, the normal removal of the
if @var{function} adjusts point before or after inserting the object.
@item undo
-If @var{undo} is present and non-nil, it is a function that will be
+If @var{undo} is present and non-@code{nil}, 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
@deffn Command yank &optional arg
@cindex inserting killed text
-This command inserts before point the text in the first entry in the
+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 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 non-@code{nil} 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.
-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.
+@code{yank} 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.
-@code{yank} does not alter the contents of the kill ring or rotate it.
-It returns @code{nil}.
+@code{yank} returns @code{nil}.
@end deffn
-@deffn Command yank-pop arg
+@deffn Command yank-pop &optional arg
This command replaces the just-yanked entry from the kill ring with a
different entry from the kill ring.
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
If this variable is non-@code{nil}, the function @code{yank-pop} uses
its value instead of @code{delete-region} to delete the text
inserted by the previous @code{yank} or
-@code{yank-pop} command.
+@code{yank-pop} 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}
If @var{n} is zero, indicating a request for the latest kill,
@code{current-kill} calls the value of
-@code{interprogram-paste-function} (documented below) before consulting
-the kill ring.
+@code{interprogram-paste-function} (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.
@end defun
-@defun kill-new string &optional yank-handler
-This function puts the text @var{string} into the kill ring as a new
-entry at the front of the ring. It discards the oldest entry if
-appropriate. It also invokes the value of
+@defun 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
@code{interprogram-cut-function} (see below).
+If @var{replace} is non-@code{nil}, then @code{kill-new} replaces the
+first element of the kill ring with @var{string}, rather than pushing
+@var{string} onto the kill ring.
+
If @var{yank-handler} is non-@code{nil}, this puts that value onto
the string of killed text, as a @code{yank-handler} property.
-@xref{Yanking}.
+@xref{Yanking}. Note that if @var{yank-handler} is @code{nil}, then
+@code{kill-new} copies any @code{yank-handler} properties present on
+@var{string} onto the kill ring, as it does with other text properties.
@end defun
@defun kill-append string before-p &optional yank-handler
This function appends the text @var{string} to the first entry in the
-kill ring. Normally @var{string} goes at the end of the entry, but if
+kill ring and makes the yanking pointer point to the combined entry.
+Normally @var{string} goes at the end of the entry, but if
@var{before-p} is non-@code{nil}, 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 @code{kill-new}.
+function also invokes the value of @code{interprogram-cut-function}
+(see below). This handles @var{yank-handler} just like
+@code{kill-new}, except that if @var{yank-handler} is different from
+the @code{yank-handler} property of the first entry of the kill ring,
+@code{kill-append} pushes the concatenated string onto the kill ring,
+instead of replacing the original first entry with it.
@end defun
@defvar interprogram-paste-function
If the value is a function, @code{current-kill} calls it to get the
``most recent kill''. If the function returns a non-@code{nil} value,
then that value is used as the ``most recent kill''. If it returns
-@code{nil}, then the first element of @code{kill-ring} is used.
+@code{nil}, 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
@defvar 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
-@code{nil} or a function of one argument.
+@code{nil} 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 an argument.
+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 from the newly killed text. @xref{Window System Selections}.
+selection (and first cut buffer) from the newly killed text.
+@xref{Window System Selections}.
@end defvar
@node Internals of Kill Ring
@defopt 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 30.
+value for @code{kill-ring-max} is 60.
@end defopt
@node Undo
@item (@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})}.
+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.
@item (t @var{high} . @var{low})
This kind of element indicates that an unmodified buffer became
(put-text-property @var{beg} @var{end} @var{property} @var{value})
@end example
+@item (apply @var{funname} . @var{args})
+This kind of element records a change that can be undone by evaluating
+(@code{apply} @var{funname} @var{args}).
+
+@item (apply @var{delta} @var{beg} @var{end} @var{funname} . @var{args})
+This kind of element records a change that can be undone by evaluating
+(@code{apply} @var{funname} @var{args}). The integer values @var{beg}
+and @var{end} is buffer positions of the range affected by this change
+and @var{delta} is an integer value which is the number of bytes added
+or deleted in that range by this change. This kind of element
+enables undo limited to a region to determine whether the element
+pertains to that region.
+
@item (@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
undo individual replacements one by one.
@end defun
+@defvar undo-in-progress
+This variable is normally @code{nil}, but the undo commands bind it to
+@code{t}. This is so that various kinds of change hooks can tell when
+they're being called for the sake of undoing.
+@end defvar
+
@defun 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
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}.
@end defun
@node Maintaining Undo
You cannot specify any other buffer.
@end deffn
-@deffn Command buffer-disable-undo &optional buffer
-@deffnx Command buffer-flush-undo &optional buffer
+@deffn Command buffer-disable-undo &optional buffer-or-name
+@deffnx Command buffer-flush-undo &optional buffer-or-name
@cindex disable undo
-This function discards the undo list of @var{buffer}, and disables
+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} is already disabled, this function
+the undo list of @var{buffer-or-name} is already disabled, this function
has no effect.
This function returns @code{nil}.
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.) Two variables control the range of acceptable
-sizes: @code{undo-limit} and @code{undo-strong-limit}.
+strings of deleted text.) Three variables control the range of acceptable
+sizes: @code{undo-limit}, @code{undo-strong-limit} and
+@code{undo-outer-limit}.
-@defvar undo-limit
+@defopt 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.
-@end defvar
+@end defopt
-@defvar undo-strong-limit
+@defopt 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 never discarded no matter how big it is.
-@end defvar
+change group is only discarded if it exceeds @code{undo-outer-limit}.
+@end defopt
+
+@defopt 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.
+@end defopt
@node Filling
@comment node-name, next, previous, up
@end defun
@defopt sentence-end-double-space
+@anchor{Definition of sentence-end-double-space}
If this variable is non-@code{nil}, 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.
BEG and END (region to sort).
The variable `sort-fold-case' determines\
whether alphabetic case affects
-the sort order.
+the sort order."
@end group
@group
(interactive "P\nr")
@deffn Command sort-numeric-fields field start end
This command sorts lines in the region between @var{start} and
-@var{end}, comparing them numerically by the @var{field}th field of each
-line. The specified field must contain a number in each line of the
-region. Fields are separated by whitespace and numbered starting from
-1. If @var{field} is negative, sorting is by the
-@w{@minus{}@var{field}th} field from the end of the line. This command
-is useful for sorting tables.
+@var{end}, 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
+@w{@minus{}@var{field}th} field from the end of the line. This
+command is useful for sorting tables.
@end deffn
+@defopt sort-numeric-base
+This variable specifies the default radix for
+@code{sort-numeric-fields} to parse numbers.
+@end defopt
+
@deffn Command sort-columns reverse &optional beg end
This command sorts the lines in the region between @var{beg} and
-@var{end}, 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.
+@var{end}, 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 non-@code{nil}, the sort is in reverse order.
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.
+arbitrarily high. The first (or leftmost) column is numbered 0. They
+also ignore overlays and text properties, aside from invisibility.
@defun current-column
This function returns the horizontal position of point, measured in
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
the @var{prop} property of that symbol.
@end defun
-@defun get-char-property pos prop &optional object
+@defun 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}.
overlays.
@end defun
+@defun 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}.
+@end defun
+
@defvar 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
A face name (a symbol or string).
@item
-Starting in Emacs 21, a property list of face attributes. This has the
+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
If the value of the @code{help-echo} property is a function, that
function is called with three arguments, @var{window}, @var{object} and
-@var{position} and should return a help string or @var{nil} for
+@var{pos} 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{position}
+string which had the @code{help-echo} property. The @var{pos}
argument is as follows:
@itemize @bullet{}
commands. The property's value for the character before point applies
if it is non-@code{nil} and rear-sticky, and the property's value for
the character after point applies if it is non-@code{nil} and
-front-sticky. When the value applies, it is used for key lookup
-before the buffer's local map. (For mouse clicks, the position of the
-click is used instead of the position of point.) If the property
-value is a symbol, the symbol's function definition is used as the
-keymap. @xref{Active Keymaps}.
+front-sticky. (For mouse clicks, the position of the click is used
+instead of the position of point.) If the property value is a symbol,
+the symbol's function definition is used as the keymap.
+
+When this keymap applies, it is used for key lookup before the minor
+mode keymaps and before the buffer's local map. @xref{Active
+Keymaps}.
@item local-map
@kindex local-map @r{(text property)}
@code{beginning-of-line} stop moving at a field boundary.
@xref{Fields}.
+@item cursor
+@kindex 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 non-@code{nil} @var{cursor} text property.
+
+@item pointer
+@kindex pointer @r{(text property)}
+This specifies a specific pointer shape when the mouse pointer is over
+this text or image. See the variable @var{void-area-text-pointer}
+for possible pointer shapes.
+
+@item line-spacing
+@kindex 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}.
+
+@item line-height
+@kindex 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.
+@xref{Line Height}.
+
@item modification-hooks
@cindex change hooks for a character
@cindex hooks for changing a character
@code{point-left} functions are called first, followed by all the
@code{point-entered} functions.
-It is possible using @code{char-after} to examine characters at various
-positions without moving point to those positions. Only an actual
-change in the value of point runs these hook 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.
@end table
@defvar inhibit-point-motion-hooks
@item 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 variable
-@code{use-hard-newlines} is non-@code{nil}.
+across them. However, this property takes effect only if the
+@code{use-hard-newlines} minor mode is enabled. @xref{Hard and Soft
+Newlines,, Hard and Soft Newlines, emacs, The GNU Emacs Manual}.
@item right-margin
This property specifies an extra right margin for filling this part of the
global definition) remains available for the rest of the text in the
buffer.
+@node Links and Mouse-1
+@subsection Links and Mouse-1
+@cindex follow links
+@cindex mouse-1
+
+ The normal Emacs command for activating text in read-only buffers is
+@key{Mouse-2}, 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 behaviour through the variable
+@code{mouse-1-click-follows-link}.
+
+ To define text as a link at the Lisp level, you should bind the
+@code{mouse-2} event to a command to follow the link. Then, to indicate that
+@key{Mouse-1} should also follow the link, you should specify a
+@code{follow-link} condition either as a text property or as a key
+binding:
+
+@table @asis
+@item @code{follow-link} property
+If the clickable text has a non-@code{nil} @code{follow-link} text or overlay
+property, that specifies the condition.
+
+@item @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.
+@end 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
+@key{Mouse-1} should handle the link.
+
+@table @asis
+@item @code{mouse-face}
+If the condition is @code{mouse-face}, a position is inside a link if
+there is a non-@code{nil} @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}:
+
+@example
+(define-key Info-mode-map [follow-link] 'mouse-face)
+@end example
+
+@item a function
+If the condition is a valid function, @var{func}, then a position
+@var{pos} is inside a link if @code{(@var{func} @var{pos})} evaluates
+to non-@code{nil}. 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:
+
+@example
+(define-key map [follow-link]
+ (lambda (pos)
+ (if (eq (get-char-property pos 'face) 'cvs-filename-face) t)))
+@end example
+
+@item 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.
+@end table
+
+@noindent
+The action code tells @key{Mouse-1} how to follow the link:
+
+@table @asis
+@item 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"},
+@key{Mouse-1} translates into @kbd{f}. If it is @code{[foo]},
+@key{Mouse-1} translates into @key{foo}.
+
+@item anything else
+For any other non-@code{nil} action code, the @code{mouse-1} event is
+translated into a @code{mouse-2} event at the same position.
+@end table
+
+ To define @key{Mouse-1} to activate a button defined with
+@code{define-button-type}, 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}:
+
+@smallexample
+(define-button-type 'help-xref
+ 'follow-link t
+ 'action #'help-button-action)
+@end smallexample
+
+ To define @key{Mouse-1} on a widget defined with
+@code{define-widget}, 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}:
+
+@smallexample
+(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%]")
+@end smallexample
+
+@defun mouse-on-link-p pos
+@tindex mouse-on-link-p
+This function returns non-@code{nil} if position @var{pos} in the
+current buffer is on a link.
+@end defun
+
@node Fields
@subsection Defining and Using Fields
@cindex fields
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; @code{(aref @var{table}
-@var{ochar})} gives the translated character corresponding to
-@var{ochar}. If the length of @var{table} is less than 256, any
+The translation table @var{table} is a string or a char-table;
+@code{(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.
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 @sc{ascii} characters and their meta variants
+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.
@cindex base 64 encoding
Base 64 code is used in email to encode a sequence of 8-bit bytes as
-a longer sequence of @sc{ascii} graphic characters. It is defined in
+a longer sequence of @acronym{ASCII} graphic characters. It is defined in
Internet RFC@footnote{
An RFC, an acronym for @dfn{Request for Comments}, is a numbered
Internet informational document describing a standard. RFCs are
If an error (or other nonlocal exit) occurs inside the body of
@code{atomic-change-group}, 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.
+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
arguments.
@end defvar
- Output of messges into the @samp{*Messages*} buffer does not
+ Output of messages into the @samp{*Messages*} buffer does not
call these functions.
@defmac combine-after-change-calls body...
@code{after-change-functions} within
the body of a @code{combine-after-change-calls} form.
-@strong{Note:} If the changes you combine occur in widely scattered
+@strong{Warning:} 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.
HCoop / bpt / emacs.git / blobdiff