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[Emacs-diffs] Changes to positions.texi
|
From: |
Glenn Morris |
|
Subject: |
[Emacs-diffs] Changes to positions.texi |
|
Date: |
Thu, 06 Sep 2007 04:13:49 +0000 |
CVSROOT: /sources/emacs
Module name: emacs
Changes by: Glenn Morris <gm> 07/09/06 04:13:48
Index: positions.texi
===================================================================
RCS file: positions.texi
diff -N positions.texi
--- positions.texi 7 Apr 2007 01:59:10 -0000 1.65
+++ /dev/null 1 Jan 1970 00:00:00 -0000
@@ -1,1004 +0,0 @@
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/positions
address@hidden Positions, Markers, Frames, Top
address@hidden Positions
address@hidden position (in buffer)
-
- A @dfn{position} is the index of a character in the text of a buffer.
-More precisely, a position identifies the place between two characters
-(or before the first character, or after the last character), so we can
-speak of the character before or after a given position. However, we
-often speak of the character ``at'' a position, meaning the character
-after that position.
-
- Positions are usually represented as integers starting from 1, but
-can also be represented as @dfn{markers}---special objects that
-relocate automatically when text is inserted or deleted so they stay
-with the surrounding characters. Functions that expect an argument to
-be a position (an integer), but accept a marker as a substitute,
-normally ignore which buffer the marker points into; they convert the
-marker to an integer, and use that integer, exactly as if you had
-passed the integer as the argument, even if the marker points to the
-``wrong'' buffer. A marker that points nowhere cannot convert to an
-integer; using it instead of an integer causes an error.
address@hidden
-
- See also the ``field'' feature (@pxref{Fields}), which provides
-functions that are used by many cursor-motion commands.
-
address@hidden
-* Point:: The special position where editing takes place.
-* Motion:: Changing point.
-* Excursions:: Temporary motion and buffer changes.
-* Narrowing:: Restricting editing to a portion of the buffer.
address@hidden menu
-
address@hidden Point
address@hidden Point
address@hidden point
-
- @dfn{Point} is a special buffer position used by many editing
-commands, including the self-inserting typed characters and text
-insertion functions. Other commands move point through the text
-to allow editing and insertion at different places.
-
- Like other positions, point designates a place between two characters
-(or before the first character, or after the last character), rather
-than a particular character. Usually terminals display the cursor over
-the character that immediately follows point; point is actually before
-the character on which the cursor sits.
-
address@hidden point with narrowing
- The value of point is a number no less than 1, and no greater than the
-buffer size plus 1. If narrowing is in effect (@pxref{Narrowing}), then
-point is constrained to fall within the accessible portion of the buffer
-(possibly at one end of it).
-
- Each buffer has its own value of point, which is independent of the
-value of point in other buffers. Each window also has a value of point,
-which is independent of the value of point in other windows on the same
-buffer. This is why point can have different values in various windows
-that display the same buffer. When a buffer appears in only one window,
-the buffer's point and the window's point normally have the same value,
-so the distinction is rarely important. @xref{Window Point}, for more
-details.
-
address@hidden point
address@hidden current buffer position
-This function returns the value of point in the current buffer,
-as an integer.
-
address@hidden 700
address@hidden
address@hidden
-(point)
- @result{} 175
address@hidden group
address@hidden example
address@hidden defun
-
address@hidden point-min
-This function returns the minimum accessible value of point in the
-current buffer. This is normally 1, but if narrowing is in effect, it
-is the position of the start of the region that you narrowed to.
-(@xref{Narrowing}.)
address@hidden defun
-
address@hidden point-max
-This function returns the maximum accessible value of point in the
-current buffer. This is @code{(1+ (buffer-size))}, unless narrowing is
-in effect, in which case it is the position of the end of the region
-that you narrowed to. (@xref{Narrowing}.)
address@hidden defun
-
address@hidden buffer-end flag
-This function returns @code{(point-max)} if @var{flag} is greater than
-0, @code{(point-min)} otherwise. The argument @var{flag} must be a
-number.
address@hidden defun
-
address@hidden buffer-size &optional buffer
-This function returns the total number of characters in the current
-buffer. In the absence of any narrowing (@pxref{Narrowing}),
address@hidden returns a value one larger than this.
-
-If you specify a buffer, @var{buffer}, then the value is the
-size of @var{buffer}.
-
address@hidden
address@hidden
-(buffer-size)
- @result{} 35
address@hidden group
address@hidden
-(point-max)
- @result{} 36
address@hidden group
address@hidden example
address@hidden defun
-
address@hidden Motion
address@hidden Motion
address@hidden motion by chars, words, lines, lists
-
- Motion functions change the value of point, either relative to the
-current value of point, relative to the beginning or end of the buffer,
-or relative to the edges of the selected window. @xref{Point}.
-
address@hidden
-* Character Motion:: Moving in terms of characters.
-* Word Motion:: Moving in terms of words.
-* Buffer End Motion:: Moving to the beginning or end of the buffer.
-* Text Lines:: Moving in terms of lines of text.
-* Screen Lines:: Moving in terms of lines as displayed.
-* List Motion:: Moving by parsing lists and sexps.
-* Skipping Characters:: Skipping characters belonging to a certain set.
address@hidden menu
-
address@hidden Character Motion
address@hidden Motion by Characters
-
- These functions move point based on a count of characters.
address@hidden is the fundamental primitive; the other functions use
-that.
-
address@hidden Command goto-char position
-This function sets point in the current buffer to the value
address@hidden If @var{position} is less than 1, it moves point to the
-beginning of the buffer. If @var{position} is greater than the length
-of the buffer, it moves point to the end.
-
-If narrowing is in effect, @var{position} still counts from the
-beginning of the buffer, but point cannot go outside the accessible
-portion. If @var{position} is out of range, @code{goto-char} moves
-point to the beginning or the end of the accessible portion.
-
-When this function is called interactively, @var{position} is the
-numeric prefix argument, if provided; otherwise it is read from the
-minibuffer.
-
address@hidden returns @var{position}.
address@hidden deffn
-
address@hidden Command forward-char &optional count
address@hidden @kindex beginning-of-buffer
address@hidden @kindex end-of-buffer
-This function moves point @var{count} characters forward, towards the
-end of the buffer (or backward, towards the beginning of the buffer, if
address@hidden is negative). If @var{count} is @code{nil}, the default
-is 1.
-
-If this attempts to move past the beginning or end of the buffer (or
-the limits of the accessible portion, when narrowing is in effect), it
-signals an error with error symbol @code{beginning-of-buffer} or
address@hidden
-
-In an interactive call, @var{count} is the numeric prefix argument.
address@hidden deffn
-
address@hidden Command backward-char &optional count
-This is just like @code{forward-char} except that it moves
-in the opposite direction.
address@hidden deffn
-
address@hidden Word Motion
address@hidden Motion by Words
-
- These functions for parsing words use the syntax table to decide
-whether a given character is part of a word. @xref{Syntax Tables}.
-
address@hidden Command forward-word &optional count
-This function moves point forward @var{count} words (or backward if
address@hidden is negative). If @var{count} is @code{nil}, it moves
-forward one word.
-
-``Moving one word'' means moving until point crosses a
-word-constituent character and then encounters a word-separator
-character. However, this function cannot move point past the boundary
-of the accessible portion of the buffer, or across a field boundary
-(@pxref{Fields}). The most common case of a field boundary is the end
-of the prompt in the minibuffer.
-
-If it is possible to move @var{count} words, without being stopped
-prematurely by the buffer boundary or a field boundary, the value is
address@hidden Otherwise, the return value is @code{nil} and point stops at
-the buffer boundary or field boundary.
-
-If @code{inhibit-field-text-motion} is address@hidden,
-this function ignores field boundaries.
-
-In an interactive call, @var{count} is specified by the numeric prefix
-argument. If @var{count} is omitted or @code{nil}, it defaults to 1.
address@hidden deffn
-
address@hidden Command backward-word &optional count
-This function is just like @code{forward-word}, except that it moves
-backward until encountering the front of a word, rather than forward.
address@hidden deffn
-
address@hidden words-include-escapes
address@hidden Emacs 19 feature
-This variable affects the behavior of @code{forward-word} and everything
-that uses it. If it is address@hidden, then characters in the
-``escape'' and ``character quote'' syntax classes count as part of
-words. Otherwise, they do not.
address@hidden defvar
-
address@hidden inhibit-field-text-motion
-If this variable is address@hidden, certain motion functions including
address@hidden, @code{forward-sentence}, and
address@hidden ignore field boundaries.
address@hidden defvar
-
address@hidden Buffer End Motion
address@hidden Motion to an End of the Buffer
address@hidden move to beginning or end of buffer
-
- To move point to the beginning of the buffer, write:
-
address@hidden
address@hidden
-(goto-char (point-min))
address@hidden group
address@hidden example
-
address@hidden
-Likewise, to move to the end of the buffer, use:
-
address@hidden
address@hidden
-(goto-char (point-max))
address@hidden group
address@hidden example
-
- Here are two commands that users use to do these things. They are
-documented here to warn you not to use them in Lisp programs, because
-they set the mark and display messages in the echo area.
-
address@hidden Command beginning-of-buffer &optional n
-This function moves point to the beginning of the buffer (or the limits
-of the accessible portion, when narrowing is in effect), setting the
-mark at the previous position (except in Transient Mark mode, if
-the mark is already active, it does not set the mark.)
-
-If @var{n} is address@hidden, then it puts point @var{n} tenths of the
-way from the beginning of the accessible portion of the buffer. In an
-interactive call, @var{n} is the numeric prefix argument, if provided;
-otherwise @var{n} defaults to @code{nil}.
-
address@hidden:} Don't use this function in Lisp programs!
address@hidden deffn
-
address@hidden Command end-of-buffer &optional n
-This function moves point to the end of the buffer (or the limits of
-the accessible portion, when narrowing is in effect), setting the mark
-at the previous position (except in Transient Mark mode when the mark
-is already active). If @var{n} is address@hidden, then it puts point
address@hidden tenths of the way from the end of the accessible portion of
-the buffer.
-
-In an interactive call, @var{n} is the numeric prefix argument,
-if provided; otherwise @var{n} defaults to @code{nil}.
-
address@hidden:} Don't use this function in Lisp programs!
address@hidden deffn
-
address@hidden Text Lines
address@hidden Motion by Text Lines
address@hidden lines
-
- Text lines are portions of the buffer delimited by newline characters,
-which are regarded as part of the previous line. The first text line
-begins at the beginning of the buffer, and the last text line ends at
-the end of the buffer whether or not the last character is a newline.
-The division of the buffer into text lines is not affected by the width
-of the window, by line continuation in display, or by how tabs and
-control characters are displayed.
-
address@hidden Command goto-line line
-This function moves point to the front of the @var{line}th line,
-counting from line 1 at beginning of the buffer. If @var{line} is less
-than 1, it moves point to the beginning of the buffer. If @var{line} is
-greater than the number of lines in the buffer, it moves point to the
-end of the buffer---that is, the @emph{end of the last line} of the
-buffer. This is the only case in which @code{goto-line} does not
-necessarily move to the beginning of a line.
-
-If narrowing is in effect, then @var{line} still counts from the
-beginning of the buffer, but point cannot go outside the accessible
-portion. So @code{goto-line} moves point to the beginning or end of the
-accessible portion, if the line number specifies an inaccessible
-position.
-
-The return value of @code{goto-line} is the difference between
address@hidden and the line number of the line to which point actually was
-able to move (in the full buffer, before taking account of narrowing).
-Thus, the value is positive if the scan encounters the real end of the
-buffer before finding the specified line. The value is zero if scan
-encounters the end of the accessible portion but not the real end of the
-buffer.
-
-In an interactive call, @var{line} is the numeric prefix argument if
-one has been provided. Otherwise @var{line} is read in the minibuffer.
address@hidden deffn
-
address@hidden Command beginning-of-line &optional count
-This function moves point to the beginning of the current line. With an
-argument @var{count} not @code{nil} or 1, it moves forward
address@hidden@minus{}1 lines and then to the beginning of the line.
-
-This function does not move point across a field boundary
-(@pxref{Fields}) unless doing so would move beyond there to a
-different line; therefore, if @var{count} is @code{nil} or 1, and
-point starts at a field boundary, point does not move. To ignore
-field boundaries, either bind @code{inhibit-field-text-motion} to
address@hidden, or use the @code{forward-line} function instead. For
-instance, @code{(forward-line 0)} does the same thing as
address@hidden(beginning-of-line)}, except that it ignores field boundaries.
-
-If this function reaches the end of the buffer (or of the accessible
-portion, if narrowing is in effect), it positions point there. No error
-is signaled.
address@hidden deffn
-
address@hidden line-beginning-position &optional count
-Return the position that @code{(beginning-of-line @var{count})}
-would move to.
address@hidden defun
-
address@hidden Command end-of-line &optional count
-This function moves point to the end of the current line. With an
-argument @var{count} not @code{nil} or 1, it moves forward
address@hidden@minus{}1 lines and then to the end of the line.
-
-This function does not move point across a field boundary
-(@pxref{Fields}) unless doing so would move beyond there to a
-different line; therefore, if @var{count} is @code{nil} or 1, and
-point starts at a field boundary, point does not move. To ignore
-field boundaries, bind @code{inhibit-field-text-motion} to @code{t}.
-
-If this function reaches the end of the buffer (or of the accessible
-portion, if narrowing is in effect), it positions point there. No error
-is signaled.
address@hidden deffn
-
address@hidden line-end-position &optional count
-Return the position that @code{(end-of-line @var{count})}
-would move to.
address@hidden defun
-
address@hidden Command forward-line &optional count
address@hidden beginning of line
-This function moves point forward @var{count} lines, to the beginning of
-the line. If @var{count} is negative, it moves point
address@hidden@var{count} lines backward, to the beginning of a line. If
address@hidden is zero, it moves point to the beginning of the current
-line. If @var{count} is @code{nil}, that means 1.
-
-If @code{forward-line} encounters the beginning or end of the buffer (or
-of the accessible portion) before finding that many lines, it sets point
-there. No error is signaled.
-
address@hidden returns the difference between @var{count} and the
-number of lines actually moved. If you attempt to move down five lines
-from the beginning of a buffer that has only three lines, point stops at
-the end of the last line, and the value will be 2.
-
-In an interactive call, @var{count} is the numeric prefix argument.
address@hidden deffn
-
address@hidden count-lines start end
address@hidden lines in region
address@hidden of count-lines}
-This function returns the number of lines between the positions
address@hidden and @var{end} in the current buffer. If @var{start} and
address@hidden are equal, then it returns 0. Otherwise it returns at least
-1, even if @var{start} and @var{end} are on the same line. This is
-because the text between them, considered in isolation, must contain at
-least one line unless it is empty.
-
-Here is an example of using @code{count-lines}:
-
address@hidden
address@hidden
-(defun current-line ()
- "Return the vertical position of address@hidden"
- (+ (count-lines (window-start) (point))
- (if (= (current-column) 0) 1 0)))
address@hidden group
address@hidden example
address@hidden defun
-
address@hidden line-number-at-pos &optional pos
address@hidden line number
-This function returns the line number in the current buffer
-corresponding to the buffer position @var{pos}. If @var{pos} is @code{nil}
-or omitted, the current buffer position is used.
address@hidden defun
-
address@hidden
address@hidden ================
-The @code{previous-line} and @code{next-line} commands are functions
-that should not be used in programs. They are for users and are
-mentioned here only for completeness.
-
address@hidden Command previous-line count
address@hidden goal column
-This function moves point up @var{count} lines (down if @var{count}
-is negative). In moving, it attempts to keep point in the ``goal column''
-(normally the same column that it was at the beginning of the move).
-
-If there is no character in the target line exactly under the current
-column, point is positioned after the character in that line which
-spans this column, or at the end of the line if it is not long enough.
-
-If it attempts to move beyond the top or bottom of the buffer (or clipped
-region), then point is positioned in the goal column in the top or
-bottom line. No error is signaled.
-
-In an interactive call, @var{count} will be the numeric
-prefix argument.
-
-The command @code{set-goal-column} can be used to create a semipermanent
-goal column to which this command always moves. Then it does not try to
-move vertically.
-
-If you are thinking of using this in a Lisp program, consider using
address@hidden with a negative argument instead. It is usually easier
-to use and more reliable (no dependence on goal column, etc.).
address@hidden deffn
-
address@hidden Command next-line count
-This function moves point down @var{count} lines (up if @var{count}
-is negative). In moving, it attempts to keep point in the ``goal column''
-(normally the same column that it was at the beginning of the move).
-
-If there is no character in the target line exactly under the current
-column, point is positioned after the character in that line which
-spans this column, or at the end of the line if it is not long enough.
-
-If it attempts to move beyond the top or bottom of the buffer (or clipped
-region), then point is positioned in the goal column in the top or
-bottom line. No error is signaled.
-
-In the case where the @var{count} is 1, and point is on the last
-line of the buffer (or clipped region), a new empty line is inserted at the
-end of the buffer (or clipped region) and point moved there.
-
-In an interactive call, @var{count} will be the numeric
-prefix argument.
-
-The command @code{set-goal-column} can be used to create a semipermanent
-goal column to which this command always moves. Then it does not try to
-move vertically.
-
-If you are thinking of using this in a Lisp program, consider using
address@hidden instead. It is usually easier
-to use and more reliable (no dependence on goal column, etc.).
address@hidden deffn
-
address@hidden ================
address@hidden ignore
-
- Also see the functions @code{bolp} and @code{eolp} in @ref{Near Point}.
-These functions do not move point, but test whether it is already at the
-beginning or end of a line.
-
address@hidden Screen Lines
address@hidden Motion by Screen Lines
-
- The line functions in the previous section count text lines, delimited
-only by newline characters. By contrast, these functions count screen
-lines, which are defined by the way the text appears on the screen. A
-text line is a single screen line if it is short enough to fit the width
-of the selected window, but otherwise it may occupy several screen
-lines.
-
- In some cases, text lines are truncated on the screen rather than
-continued onto additional screen lines. In these cases,
address@hidden moves point much like @code{forward-line}.
address@hidden
-
- Because the width of a given string depends on the flags that control
-the appearance of certain characters, @code{vertical-motion} behaves
-differently, for a given piece of text, depending on the buffer it is
-in, and even on the selected window (because the width, the truncation
-flag, and display table may vary between windows). @xref{Usual
-Display}.
-
- These functions scan text to determine where screen lines break, and
-thus take time proportional to the distance scanned. If you intend to
-use them heavily, Emacs provides caches which may improve the
-performance of your code. @xref{Truncation, cache-long-line-scans}.
-
address@hidden vertical-motion count &optional window
-This function moves point to the start of the screen line @var{count}
-screen lines down from the screen line containing point. If @var{count}
-is negative, it moves up instead.
-
address@hidden returns the number of screen lines over which it
-moved point. The value may be less in absolute value than @var{count}
-if the beginning or end of the buffer was reached.
-
-The window @var{window} is used for obtaining parameters such as the
-width, the horizontal scrolling, and the display table. But
address@hidden always operates on the current buffer, even if
address@hidden currently displays some other buffer.
address@hidden defun
-
address@hidden count-screen-lines &optional beg end count-final-newline window
-This function returns the number of screen lines in the text from
address@hidden to @var{end}. The number of screen lines may be different
-from the number of actual lines, due to line continuation, the display
-table, etc. If @var{beg} and @var{end} are @code{nil} or omitted,
-they default to the beginning and end of the accessible portion of the
-buffer.
-
-If the region ends with a newline, that is ignored unless the optional
-third argument @var{count-final-newline} is address@hidden
-
-The optional fourth argument @var{window} specifies the window for
-obtaining parameters such as width, horizontal scrolling, and so on.
-The default is to use the selected window's parameters.
-
-Like @code{vertical-motion}, @code{count-screen-lines} always uses the
-current buffer, regardless of which buffer is displayed in
address@hidden This makes possible to use @code{count-screen-lines} in
-any buffer, whether or not it is currently displayed in some window.
address@hidden defun
-
address@hidden Command move-to-window-line count
-This function moves point with respect to the text currently displayed
-in the selected window. It moves point to the beginning of the screen
-line @var{count} screen lines from the top of the window. If
address@hidden is negative, that specifies a position
address@hidden@address@hidden lines from the bottom (or the last line of the
-buffer, if the buffer ends above the specified screen position).
-
-If @var{count} is @code{nil}, then point moves to the beginning of the
-line in the middle of the window. If the absolute value of @var{count}
-is greater than the size of the window, then point moves to the place
-that would appear on that screen line if the window were tall enough.
-This will probably cause the next redisplay to scroll to bring that
-location onto the screen.
-
-In an interactive call, @var{count} is the numeric prefix argument.
-
-The value returned is the window line number point has moved to, with
-the top line in the window numbered 0.
address@hidden deffn
-
address@hidden compute-motion from frompos to topos width offsets window
-This function scans the current buffer, calculating screen positions.
-It scans the buffer forward from position @var{from}, assuming that is
-at screen coordinates @var{frompos}, to position @var{to} or coordinates
address@hidden, whichever comes first. It returns the ending buffer
-position and screen coordinates.
-
-The coordinate arguments @var{frompos} and @var{topos} are cons cells of
-the form @code{(@var{hpos} . @var{vpos})}.
-
-The argument @var{width} is the number of columns available to display
-text; this affects handling of continuation lines. @code{nil} means
-the actual number of usable text columns in the window, which is
-equivalent to the value returned by @code{(window-width window)}.
-
-The argument @var{offsets} is either @code{nil} or a cons cell of the
-form @code{(@var{hscroll} . @var{tab-offset})}. Here @var{hscroll} is
-the number of columns not being displayed at the left margin; most
-callers get this by calling @code{window-hscroll}. Meanwhile,
address@hidden is the offset between column numbers on the screen and
-column numbers in the buffer. This can be nonzero in a continuation
-line, when the previous screen lines' widths do not add up to a multiple
-of @code{tab-width}. It is always zero in a non-continuation line.
-
-The window @var{window} serves only to specify which display table to
-use. @code{compute-motion} always operates on the current buffer,
-regardless of what buffer is displayed in @var{window}.
-
-The return value is a list of five elements:
-
address@hidden
-(@var{pos} @var{hpos} @var{vpos} @var{prevhpos} @var{contin})
address@hidden example
-
address@hidden
-Here @var{pos} is the buffer position where the scan stopped, @var{vpos}
-is the vertical screen position, and @var{hpos} is the horizontal screen
-position.
-
-The result @var{prevhpos} is the horizontal position one character back
-from @var{pos}. The result @var{contin} is @code{t} if the last line
-was continued after (or within) the previous character.
-
-For example, to find the buffer position of column @var{col} of screen line
address@hidden of a certain window, pass the window's display start location
-as @var{from} and the window's upper-left coordinates as @var{frompos}.
-Pass the buffer's @code{(point-max)} as @var{to}, to limit the scan to
-the end of the accessible portion of the buffer, and pass @var{line} and
address@hidden as @var{topos}. Here's a function that does this:
-
address@hidden
-(defun coordinates-of-position (col line)
- (car (compute-motion (window-start)
- '(0 . 0)
- (point-max)
- (cons col line)
- (window-width)
- (cons (window-hscroll) 0)
- (selected-window))))
address@hidden example
-
-When you use @code{compute-motion} for the minibuffer, you need to use
address@hidden to get the horizontal position of the
-beginning of the first screen line. @xref{Minibuffer Contents}.
address@hidden defun
-
address@hidden List Motion
address@hidden node-name, next, previous, up
address@hidden Moving over Balanced Expressions
address@hidden sexp motion
address@hidden Lisp expression motion
address@hidden list motion
address@hidden balanced parenthesis motion
-
- Here are several functions concerned with balanced-parenthesis
-expressions (also called @dfn{sexps} in connection with moving across
-them in Emacs). The syntax table controls how these functions interpret
-various characters; see @ref{Syntax Tables}. @xref{Parsing
-Expressions}, for lower-level primitives for scanning sexps or parts of
-sexps. For user-level commands, see @ref{Parentheses,, Commands for
-Editing with Parentheses, emacs, The GNU Emacs Manual}.
-
address@hidden Command forward-list &optional arg
-This function moves forward across @var{arg} (default 1) balanced groups of
-parentheses. (Other syntactic entities such as words or paired string
-quotes are ignored.)
address@hidden deffn
-
address@hidden Command backward-list &optional arg
-This function moves backward across @var{arg} (default 1) balanced groups of
-parentheses. (Other syntactic entities such as words or paired string
-quotes are ignored.)
address@hidden deffn
-
address@hidden Command up-list &optional arg
-This function moves forward out of @var{arg} (default 1) levels of parentheses.
-A negative argument means move backward but still to a less deep spot.
address@hidden deffn
-
address@hidden Command down-list &optional arg
-This function moves forward into @var{arg} (default 1) levels of
-parentheses. A negative argument means move backward but still go
-deeper in parentheses (@address@hidden levels).
address@hidden deffn
-
address@hidden Command forward-sexp &optional arg
-This function moves forward across @var{arg} (default 1) balanced expressions.
-Balanced expressions include both those delimited by parentheses and
-other kinds, such as words and string constants.
address@hidden Expressions}. For example,
-
address@hidden
address@hidden
----------- Buffer: foo ----------
-(address@hidden "foo " (car x) y z)
----------- Buffer: foo ----------
address@hidden group
-
address@hidden
-(forward-sexp 3)
- @result{} nil
-
----------- Buffer: foo ----------
-(concat "foo " (car x) address@hidden z)
----------- Buffer: foo ----------
address@hidden group
address@hidden example
address@hidden deffn
-
address@hidden Command backward-sexp &optional arg
-This function moves backward across @var{arg} (default 1) balanced expressions.
address@hidden deffn
-
address@hidden Command beginning-of-defun &optional arg
-This function moves back to the @var{arg}th beginning of a defun. If
address@hidden is negative, this actually moves forward, but it still moves
-to the beginning of a defun, not to the end of one. @var{arg} defaults
-to 1.
address@hidden deffn
-
address@hidden Command end-of-defun &optional arg
-This function moves forward to the @var{arg}th end of a defun. If
address@hidden is negative, this actually moves backward, but it still moves
-to the end of a defun, not to the beginning of one. @var{arg} defaults
-to 1.
address@hidden deffn
-
address@hidden defun-prompt-regexp
-If address@hidden, this buffer-local variable holds a regular
-expression that specifies what text can appear before the
-open-parenthesis that starts a defun. That is to say, a defun begins
-on a line that starts with a match for this regular expression,
-followed by a character with open-parenthesis syntax.
address@hidden defopt
-
address@hidden open-paren-in-column-0-is-defun-start
-If this variable's value is address@hidden, an open parenthesis in
-column 0 is considered to be the start of a defun. If it is
address@hidden, an open parenthesis in column 0 has no special meaning.
-The default is @code{t}.
address@hidden defopt
-
address@hidden beginning-of-defun-function
-If address@hidden, this variable holds a function for finding the
-beginning of a defun. The function @code{beginning-of-defun}
-calls this function instead of using its normal method.
address@hidden defvar
-
address@hidden end-of-defun-function
-If address@hidden, this variable holds a function for finding the end of
-a defun. The function @code{end-of-defun} calls this function instead
-of using its normal method.
address@hidden defvar
-
address@hidden Skipping Characters
address@hidden node-name, next, previous, up
address@hidden Skipping Characters
address@hidden skipping characters
-
- The following two functions move point over a specified set of
-characters. For example, they are often used to skip whitespace. For
-related functions, see @ref{Motion and Syntax}.
-
-These functions convert the set string to multibyte if the buffer is
-multibyte, and they convert it to unibyte if the buffer is unibyte, as
-the search functions do (@pxref{Searching and Matching}).
-
address@hidden skip-chars-forward character-set &optional limit
-This function moves point in the current buffer forward, skipping over a
-given set of characters. It examines the character following point,
-then advances point if the character matches @var{character-set}. This
-continues until it reaches a character that does not match. The
-function returns the number of characters moved over.
-
-The argument @var{character-set} is a string, like the inside of a
address@hidden@dots{}]} in a regular expression except that @samp{]} does not
-terminate it, and @samp{\} quotes @samp{^}, @samp{-} or @samp{\}.
-Thus, @code{"a-zA-Z"} skips over all letters, stopping before the
-first nonletter, and @code{"^a-zA-Z"} skips nonletters stopping before
-the first letter. See @xref{Regular Expressions}. Character classes
-can also be used, e.g. @code{"[:alnum:]"}. See @pxref{Char Classes}.
-
-If @var{limit} is supplied (it must be a number or a marker), it
-specifies the maximum position in the buffer that point can be skipped
-to. Point will stop at or before @var{limit}.
-
-In the following example, point is initially located directly before the
address@hidden After the form is evaluated, point is located at the end of
-that line (between the @samp{t} of @samp{hat} and the newline). The
-function skips all letters and spaces, but not newlines.
-
address@hidden
address@hidden
----------- Buffer: foo ----------
-I read "@point{}The cat in the hat
-comes back" twice.
----------- Buffer: foo ----------
address@hidden group
-
address@hidden
-(skip-chars-forward "a-zA-Z ")
- @result{} nil
-
----------- Buffer: foo ----------
-I read "The cat in the address@hidden
-comes back" twice.
----------- Buffer: foo ----------
address@hidden group
address@hidden example
address@hidden defun
-
address@hidden skip-chars-backward character-set &optional limit
-This function moves point backward, skipping characters that match
address@hidden, until @var{limit}. It is just like
address@hidden except for the direction of motion.
-
-The return value indicates the distance traveled. It is an integer that
-is zero or less.
address@hidden defun
-
address@hidden Excursions
address@hidden Excursions
address@hidden excursion
-
- It is often useful to move point ``temporarily'' within a localized
-portion of the program, or to switch buffers temporarily. This is
-called an @dfn{excursion}, and it is done with the @code{save-excursion}
-special form. This construct initially remembers the identity of the
-current buffer, and its values of point and the mark, and restores them
-after the completion of the excursion.
-
- The forms for saving and restoring the configuration of windows are
-described elsewhere (see @ref{Window Configurations}, and @pxref{Frame
-Configurations}).
-
address@hidden save-excursion address@hidden
address@hidden mark excursion
address@hidden point excursion
-The @code{save-excursion} special form saves the identity of the current
-buffer and the values of point and the mark in it, evaluates
address@hidden, and finally restores the buffer and its saved values of
-point and the mark. All three saved values are restored even in case of
-an abnormal exit via @code{throw} or error (@pxref{Nonlocal Exits}).
-
-The @code{save-excursion} special form is the standard way to switch
-buffers or move point within one part of a program and avoid affecting
-the rest of the program. It is used more than 4000 times in the Lisp
-sources of Emacs.
-
address@hidden does not save the values of point and the mark for
-other buffers, so changes in other buffers remain in effect after
address@hidden exits.
-
address@hidden window excursions
-Likewise, @code{save-excursion} does not restore window-buffer
-correspondences altered by functions such as @code{switch-to-buffer}.
-One way to restore these correspondences, and the selected window, is to
-use @code{save-window-excursion} inside @code{save-excursion}
-(@pxref{Window Configurations}).
-
-The value returned by @code{save-excursion} is the result of the last
-form in @var{body}, or @code{nil} if no body forms were given.
-
address@hidden
address@hidden
-(save-excursion @var{forms})
address@hidden
-(let ((old-buf (current-buffer))
- (old-pnt (point-marker))
address@hidden group
- (old-mark (copy-marker (mark-marker))))
- (unwind-protect
- (progn @var{forms})
- (set-buffer old-buf)
address@hidden
- (goto-char old-pnt)
- (set-marker (mark-marker) old-mark)))
address@hidden group
address@hidden example
address@hidden defspec
-
- @strong{Warning:} Ordinary insertion of text adjacent to the saved
-point value relocates the saved value, just as it relocates all markers.
-More precisely, the saved value is a marker with insertion type
address@hidden @xref{Marker Insertion Types}. Therefore, when the saved
-point value is restored, it normally comes before the inserted text.
-
- Although @code{save-excursion} saves the location of the mark, it does
-not prevent functions which modify the buffer from setting
address@hidden, and thus causing the deactivation of the mark
-after the command finishes. @xref{The Mark}.
-
address@hidden Narrowing
address@hidden Narrowing
address@hidden narrowing
address@hidden restriction (in a buffer)
address@hidden accessible portion (of a buffer)
-
- @dfn{Narrowing} means limiting the text addressable by Emacs editing
-commands to a limited range of characters in a buffer. The text that
-remains addressable is called the @dfn{accessible portion} of the
-buffer.
-
- Narrowing is specified with two buffer positions which become the
-beginning and end of the accessible portion. For most editing commands
-and most Emacs primitives, these positions replace the values of the
-beginning and end of the buffer. While narrowing is in effect, no text
-outside the accessible portion is displayed, and point cannot move
-outside the accessible portion.
-
- Values such as positions or line numbers, which usually count from the
-beginning of the buffer, do so despite narrowing, but the functions
-which use them refuse to operate on text that is inaccessible.
-
- The commands for saving buffers are unaffected by narrowing; they save
-the entire buffer regardless of any narrowing.
-
address@hidden Command narrow-to-region start end
-This function sets the accessible portion of the current buffer to start
-at @var{start} and end at @var{end}. Both arguments should be character
-positions.
-
-In an interactive call, @var{start} and @var{end} are set to the bounds
-of the current region (point and the mark, with the smallest first).
address@hidden deffn
-
address@hidden Command narrow-to-page &optional move-count
-This function sets the accessible portion of the current buffer to
-include just the current page. An optional first argument
address@hidden address@hidden means to move forward or backward by
address@hidden pages and then narrow to one page. The variable
address@hidden specifies where pages start and end
-(@pxref{Standard Regexps}).
-
-In an interactive call, @var{move-count} is set to the numeric prefix
-argument.
address@hidden deffn
-
address@hidden Command widen
address@hidden widening
-This function cancels any narrowing in the current buffer, so that the
-entire contents are accessible. This is called @dfn{widening}.
-It is equivalent to the following expression:
-
address@hidden
-(narrow-to-region 1 (1+ (buffer-size)))
address@hidden example
address@hidden deffn
-
address@hidden save-restriction address@hidden
-This special form saves the current bounds of the accessible portion,
-evaluates the @var{body} forms, and finally restores the saved bounds,
-thus restoring the same state of narrowing (or absence thereof) formerly
-in effect. The state of narrowing is restored even in the event of an
-abnormal exit via @code{throw} or error (@pxref{Nonlocal Exits}).
-Therefore, this construct is a clean way to narrow a buffer temporarily.
-
-The value returned by @code{save-restriction} is that returned by the
-last form in @var{body}, or @code{nil} if no body forms were given.
-
address@hidden Wordy to avoid overfull hbox. --rjc 16mar92
address@hidden:} it is easy to make a mistake when using the
address@hidden construct. Read the entire description here
-before you try it.
-
-If @var{body} changes the current buffer, @code{save-restriction} still
-restores the restrictions on the original buffer (the buffer whose
-restrictions it saved from), but it does not restore the identity of the
-current buffer.
-
address@hidden does @emph{not} restore point and the mark; use
address@hidden for that. If you use both @code{save-restriction}
-and @code{save-excursion} together, @code{save-excursion} should come
-first (on the outside). Otherwise, the old point value would be
-restored with temporary narrowing still in effect. If the old point
-value were outside the limits of the temporary narrowing, this would
-fail to restore it accurately.
-
-Here is a simple example of correct use of @code{save-restriction}:
-
address@hidden
address@hidden
----------- Buffer: foo ----------
-This is the contents of foo
-This is the contents of foo
-This is the contents of address@hidden
----------- Buffer: foo ----------
address@hidden group
-
address@hidden
-(save-excursion
- (save-restriction
- (goto-char 1)
- (forward-line 2)
- (narrow-to-region 1 (point))
- (goto-char (point-min))
- (replace-string "foo" "bar")))
-
----------- Buffer: foo ----------
-This is the contents of bar
-This is the contents of bar
-This is the contents of address@hidden
----------- Buffer: foo ----------
address@hidden group
address@hidden example
address@hidden defspec
-
address@hidden
- arch-tag: 56e8ff26-4ffe-4832-a141-7e991a2d0f87
address@hidden ignore
- [Emacs-diffs] Changes to positions.texi,
Glenn Morris <=