@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 Free Software Foundation, Inc.
+@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2000, 2001,
+@c 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@setfilename ../info/positions
@node Positions, Markers, Frames, Top
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 the marker buffer. Of course, markers used this way usually
-point to a position in the buffer that the function operates on, but
-that is entirely the programmer's responsibility. @xref{Markers}.
+ 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.
+@xref{Markers}.
See also the ``field'' feature (@pxref{Fields}), which provides
functions that are used by many cursor-motion commands.
@end defvar
@defvar inhibit-field-text-motion
-@tindex inhibit-field-text-motion
If this variable is non-@code{nil}, certain motion functions including
@code{forward-word}, @code{forward-sentence}, and
@code{forward-paragraph} ignore field boundaries.
@end deffn
@defun line-beginning-position &optional count
-@tindex line-beginning-position
Return the position that @code{(beginning-of-line @var{count})}
would move to.
@end defun
@end deffn
@defun line-end-position &optional count
-@tindex line-end-position
Return the position that @code{(end-of-line @var{count})}
would move to.
@end defun
@defun line-number-at-pos &optional pos
@cindex line number
This function returns the line number in the current buffer
-corresponding the buffer position @var{pos}. If @var{pos} is @code{nil}
+corresponding to the buffer position @var{pos}. If @var{pos} is @code{nil}
or omitted, the current buffer position is used.
@end defun
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. Use the value
-returned by @code{window-width} for the window of your choice;
-normally, use @code{(window-width @var{window})}.
+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
When you use @code{compute-motion} for the minibuffer, you need to use
@code{minibuffer-prompt-width} to get the horizontal position of the
-beginning of the first screen line. @xref{Minibuffer Misc}.
+beginning of the first screen line. @xref{Minibuffer Contents}.
@end defun
@node List Motion
@end deffn
@defopt defun-prompt-regexp
-If non-@code{nil}, this 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.
+If non-@code{nil}, 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.
@end defopt
@defopt open-paren-in-column-0-is-defun-start
@end defopt
@defvar beginning-of-defun-function
-@tindex beginning-of-defun-function
If non-@code{nil}, 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.
@end defvar
@defvar end-of-defun-function
-@tindex end-of-defun-function
If non-@code{nil}, 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.
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. @xref{Regular Expressions}.
+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
described elsewhere (see @ref{Window Configurations}, and @pxref{Frame
Configurations}).
-@defspec save-excursion forms@dots{}
+@defspec save-excursion body@dots{}
@cindex mark excursion
@cindex point excursion
@cindex current buffer 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
-@var{forms}, and finally restores the buffer and its saved values of
+@var{body}, 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}).
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 of
-@var{forms}, or @code{nil} if no @var{forms} are given.
+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.
@example
@group