@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
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2000, 2001
+@c Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@setfilename ../info/positions
@node Positions, Markers, Frames, Top
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. @xref{Markers}.
+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}.
See also the ``field'' feature (@pxref{Fields}), which provides
-functions that are used by many cursur-motion commands.
+functions that are used by many cursor-motion commands.
@menu
* Point:: The special position where editing takes place.
@end defun
@defun buffer-end flag
-This function returns @code{(point-min)} if @var{flag} is less than 1,
-@code{(point-max)} otherwise. The argument @var{flag} must be a number.
+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.
@end defun
@defun buffer-size &optional buffer
@c @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
-@var{count} is negative). If the function attempts to move point past
-the beginning or end of the buffer (or the limits of the accessible
-portion, when narrowing is in effect), an error is signaled with error
-code @code{beginning-of-buffer} or @code{end-of-buffer}.
+@var{count} 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
+@code{end-of-buffer}.
In an interactive call, @var{count} is the numeric prefix argument.
@end deffn
@deffn Command backward-char &optional count
-This function moves point @var{count} characters backward, towards the
-beginning of the buffer (or forward, towards the end of the buffer, if
-@var{count} is negative). If the function attempts to move point past
-the beginning or end of the buffer (or the limits of the accessible
-portion, when narrowing is in effect), an error is signaled with error
-code @code{beginning-of-buffer} or @code{end-of-buffer}.
-
-In an interactive call, @var{count} is the numeric prefix argument.
+This is just like @code{forward-char} except that it moves
+in the opposite direction.
@end deffn
@node Word Motion
These functions for parsing words use the syntax table to decide
whether a given character is part of a word. @xref{Syntax Tables}.
-@deffn Command forward-word count
+@deffn Command forward-word &optional count
This function moves point forward @var{count} words (or backward if
-@var{count} is negative). ``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.
+@var{count} 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
this function ignores field boundaries.
In an interactive call, @var{count} is specified by the numeric prefix
-argument.
+argument. If @var{count} is omitted or @code{nil}, it defaults to 1.
@end deffn
-@deffn Command backward-word count
+@deffn 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.
-
-In an interactive call, @var{count} is set to the numeric prefix
-argument.
-
-@c [Now optimized by compiler.]
-@c This function is rarely used in programs, as it is more efficient to
-@c call @code{forward-word} with a negative argument.
@end deffn
@defvar words-include-escapes
@deffn 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. If @var{n} is non-@code{nil}, then it
-puts point @var{n} tenths of the way from the beginning of the
-accessible portion of the buffer.
+mark at the previous position (except in Transient Mark mode, if
+the mark is already active, it does not set the mark.)
-In an interactive call, @var{n} is the numeric prefix argument,
-if provided; otherwise @var{n} defaults to @code{nil}.
+If @var{n} is non-@code{nil}, 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}.
@strong{Warning:} Don't use this function in Lisp programs!
@end deffn
@deffn 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. If @var{n} is non-@code{nil}, then it puts point
-@var{n} tenths of the way from the end of the accessible portion of the
-buffer.
+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 non-@code{nil}, then it puts point
+@var{n} 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}.
argument @var{count} not @code{nil} or 1, it moves forward
@var{count}@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
+@code{t}, or use the @code{forward-line} function instead. For
+instance, @code{(forward-line 0)} does the same thing as
+@code{(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.
argument @var{count} not @code{nil} or 1, it moves forward
@var{count}@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.
the line. If @var{count} is negative, it moves point
@minus{}@var{count} lines backward, to the beginning of a line. If
@var{count} is zero, it moves point to the beginning of the current
-line.
+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
@defun count-lines start end
@cindex lines in region
+@anchor{Definition of count-lines}
This function returns the number of lines between the positions
@var{start} and @var{end} in the current buffer. If @var{start} and
@var{end} are equal, then it returns 0. Otherwise it returns at least
(defun current-line ()
"Return the vertical position of point@dots{}"
(+ (count-lines (window-start) (point))
- (if (= (current-column) 0) 1 0)
- -1))
+ (if (= (current-column) 0) 1 0)))
@end group
@end example
@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}
+or omitted, the current buffer position is used.
+@end defun
+
@ignore
@c ================
The @code{previous-line} and @code{next-line} commands are functions
The return value is a list of five elements:
@example
-(@var{pos} @var{vpos} @var{hpos} @var{prevhpos} @var{contin})
+(@var{pos} @var{hpos} @var{vpos} @var{prevhpos} @var{contin})
@end example
@noindent
@node List Motion
@comment node-name, next, previous, up
-@subsection Moving over Balanced Expressions
+@subsection Moving over Balanced Expressions
@cindex sexp motion
@cindex Lisp expression motion
@cindex list motion
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{Lists Commands,,, emacs, The GNU
-Emacs Manual}.
+sexps. For user-level commands, see @ref{Parentheses,, Commands for
+Editing with Parentheses, emacs, The GNU Emacs Manual}.
@deffn Command forward-list &optional arg
This function moves forward across @var{arg} (default 1) balanced groups of
@end deffn
@deffn 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
+This function moves forward into @var{arg} (default 1) levels of
+parentheses. A negative argument means move backward but still go
deeper in parentheses (@minus{}@var{arg} levels).
@end deffn
This function moves backward across @var{arg} (default 1) balanced expressions.
@end deffn
-@deffn Command beginning-of-defun arg
+@deffn Command beginning-of-defun &optional arg
This function moves back to the @var{arg}th beginning of a defun. If
@var{arg} is negative, this actually moves forward, but it still moves
-to the beginning of a defun, not to the end of one.
+to the beginning of a defun, not to the end of one. @var{arg} defaults
+to 1.
@end deffn
-@deffn Command end-of-defun arg
+@deffn Command end-of-defun &optional arg
This function moves forward to the @var{arg}th end of a defun. If
@var{arg} is negative, this actually moves backward, but it still moves
-to the end of a defun, not to the beginning of one.
+to the end of a defun, not to the beginning of one. @var{arg} defaults
+to 1.
@end deffn
@defopt defun-prompt-regexp
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}).
+
@defun 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,
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 like the inside of a
-@samp{[@dots{}]} in a regular expression except that @samp{]} is never
-special 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 argument @var{character-set} is a string, like the inside of a
+@samp{[@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
@strong{Warning:} Ordinary insertion of text adjacent to the saved
point value relocates the saved value, just as it relocates all markers.
-Therefore, when the saved point value is restored, it normally comes
-before the inserted text.
+More precisely, the saved value is a marker with insertion type
+@code{nil}. @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
of the current region (point and the mark, with the smallest first).
@end deffn
-@deffn Command narrow-to-page move-count
+@deffn 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
@var{move-count} non-@code{nil} means to move forward or backward by
@end group
@end example
@end defspec
+
+@ignore
+ arch-tag: 56e8ff26-4ffe-4832-a141-7e991a2d0f87
+@end ignore