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@ -31,7 +31,7 @@ just as an integer could be used. @xref{Positions}, for a complete
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description of positions.
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A marker has two attributes: the marker position, and the marker
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buffer. The marker position is an integer which is equivalent (at a
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buffer. The marker position is an integer that is equivalent (at a
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given time) to the marker as a position in that buffer. But the
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marker's position value can change often during the life of the marker.
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Insertion and deletion of text in the buffer relocate the marker. The
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@ -141,7 +141,7 @@ accessible portion of the buffer, or to the same place as another given
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marker.
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@defun make-marker
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This functions returns a newly allocated marker that does not point
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This functions returns a newly created marker that does not point
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anywhere.
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@example
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@ -309,10 +309,10 @@ in @var{buffer}. If @var{buffer} is not provided, it defaults to
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the current buffer.
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If @var{position} is less than 1, @code{set-marker} moves @var{marker}
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to the beginning of the buffer. If the value of @var{position} is
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greater than the size of the buffer, @code{set-marker} moves marker to
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the end of the buffer. If @var{position} is @code{nil} or a marker that
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points nowhere, then @var{marker} is set to point nowhere.
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to the beginning of the buffer. If @var{position} is greater than the
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size of the buffer, @code{set-marker} moves marker to the end of the
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buffer. If @var{position} is @code{nil} or a marker that points
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nowhere, then @var{marker} is set to point nowhere.
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The value returned is @var{marker}.
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@ -365,16 +365,15 @@ explicitly. @xref{Interactive Codes}.
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Each buffer has its own value of the mark that is independent of the
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value of the mark in other buffers. When a buffer is created, the mark
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exists but does not point anywhere. We consider this state as ``the
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absence of a mark in that buffer''.
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absence of a mark in that buffer.''
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Once the mark ``exists'' in a buffer, it normally never ceases to
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exist. However, it may become @dfn{inactive}, if Transient Mark mode is
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enabled. The variable @code{mark-active}, which is always local in all
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buffers, indicates whether the mark is active: non-@code{nil} means
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yes. A command can request deactivation of the mark upon return to the
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editor command loop by setting @code{deactivate-mark} to a
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non-@code{nil} value (but this deactivation only follows if Transient
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Mark mode is enabled).
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buffers, indicates whether the mark is active: non-@code{nil} means yes.
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A command can request deactivation of the mark upon return to the editor
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command loop by setting @code{deactivate-mark} to a non-@code{nil} value
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(but this causes deactivation only if Transient Mark mode is enabled).
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The main motivation for using Transient Mark mode is that this mode
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also enables highlighting of the region when the mark is active.
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@ -399,7 +398,7 @@ this buffer.
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@defun mark-marker
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This function returns the current buffer's mark. This is the very marker
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which records the mark location inside Emacs, not a copy. Therefore,
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that records the mark location inside Emacs, not a copy. Therefore,
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changing this marker's position will directly affect the position of the mark.
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Don't do it unless that is the effect you want.
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@ -505,9 +504,15 @@ inactive.
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@defvar deactivate-mark
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If an editor command sets this variable non-@code{nil}, then the editor
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command loop deactivates the mark after the command returns.
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command loop deactivates the mark after the command returns, but only if
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Transient Mark mode is enabled.
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@end defvar
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@defun deactivate-mark
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This function deactivates the mark, but only if Transient Mark mode
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is enabled.
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@end defun
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@defvar mark-active
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The mark is active when this variable is non-@code{nil}. This variable
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is always local in each buffer.
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@ -7,15 +7,15 @@
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@chapter Positions
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@cindex position (in buffer)
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A @dfn{position} is the index of a character in the text of buffer.
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A @dfn{position} is the index of a character in the text of a buffer.
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More precisely, a position identifies the place between two characters
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(or before the first character, or after the last character), so we can
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speak of the character before or after a given position. However, the
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we often speak of the character ``at'' a position, meaning the character
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speak of the character before or after a given position. However, we
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often speak of the character ``at'' a position, meaning the character
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after that position.
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Positions are usually represented as integers starting from 1, but can
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also be represented as @dfn{markers}---special objects which relocate
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also be represented as @dfn{markers}---special objects that relocate
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automatically when text is inserted or deleted so they stay with the
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surrounding characters. @xref{Markers}.
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@ -58,7 +58,7 @@ details.
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@defun point
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@cindex current buffer position
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This function returns the position of point in the current buffer,
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This function returns the value of point in the current buffer,
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as an integer.
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@need 700
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@ -71,26 +71,26 @@ as an integer.
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@end defun
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@defun point-min
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This function returns the minimum accessible value of point in the
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current buffer. This is 1, unless narrowing is in effect, in
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which case it is the position of the start of the region that you
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narrowed to. (@xref{Narrowing}.)
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This function returns the minimum accessible value of point in the
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current buffer. This is normally 1, but if narrowing is in effect, it
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is the position of the start of the region that you narrowed to.
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(@xref{Narrowing}.)
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@end defun
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@defun point-max
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This function returns the maximum accessible value of point in the
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This function returns the maximum accessible value of point in the
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current buffer. This is @code{(1+ (buffer-size))}, unless narrowing is
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in effect, in which case it is the position of the end of the region
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that you narrowed to. (@xref{Narrowing}).
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@end defun
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@defun buffer-end flag
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This function returns @code{(point-min)} if @var{flag} is less than 1,
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This function returns @code{(point-min)} if @var{flag} is less than 1,
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@code{(point-max)} otherwise. The argument @var{flag} must be a number.
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@end defun
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@defun buffer-size
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This function returns the total number of characters in the current
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This function returns the total number of characters in the current
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buffer. In the absence of any narrowing (@pxref{Narrowing}),
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@code{point-max} returns a value one larger than this.
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@ -129,7 +129,7 @@ or relative to the edges of the selected window. @xref{Point}.
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@subsection Motion by Characters
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These functions move point based on a count of characters.
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@code{goto-char} is the fundamental primitive; the functions others use
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@code{goto-char} is the fundamental primitive; the other functions use
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that.
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@deffn Command goto-char position
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@ -192,14 +192,14 @@ argument.
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@end deffn
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@deffn Command backward-word count
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This function just like @code{forward-word}, except that it moves
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This function is just like @code{forward-word}, except that it moves
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backward until encountering the front of a word, rather than forward.
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In an interactive call, @var{count} is set to the numeric prefix
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argument.
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This function is rarely used in programs, as it is more efficient to
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call @code{forward-word} with negative argument.
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call @code{forward-word} with a negative argument.
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@end deffn
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@defvar words-include-escapes
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@ -230,7 +230,7 @@ Likewise, to move to the end of the buffer, use:
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@end group
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@end example
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Here are two commands which users use to do these things. They are
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Here are two commands that users use to do these things. They are
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documented here to warn you not to use them in Lisp programs, because
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they set the mark and display messages in the echo area.
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@ -250,7 +250,7 @@ Don't use this function in Lisp programs!
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This function moves point to the end of the buffer (or the limits of
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the accessible portion, when narrowing is in effect), setting the mark
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at the previous position. If @var{n} is non-@code{nil}, then it puts
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point @var{n} tenths of the way from the end.
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point @var{n} tenths of the way from the end of the buffer.
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In an interactive call, @var{n} is the numeric prefix argument,
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if provided; otherwise @var{n} defaults to @code{nil}.
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@ -272,10 +272,12 @@ control characters are displayed.
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@deffn Command goto-line line
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This function moves point to the front of the @var{line}th line,
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counting from line 1 at beginning of buffer. If @var{line} is less than
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1, it moves point to the beginning of the buffer. If @var{line} is
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counting from line 1 at beginning of the buffer. If @var{line} is less
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than 1, it moves point to the beginning of the buffer. If @var{line} is
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greater than the number of lines in the buffer, it moves point to the
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@emph{end of the last line} of the buffer.
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end of the buffer---that is, the @emph{end of the last line} of the
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buffer. This is the only case in which @code{goto-line} does not
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necessarily move to the beginning of a line.
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If narrowing is in effect, then @var{line} still counts from the
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beginning of the buffer, but point cannot go outside the accessible
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@ -285,8 +287,10 @@ position.
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The return value of @code{goto-line} is the difference between
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@var{line} and the line number of the line to which point actually was
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able move (in the full buffer, disregarding any narrowing). Thus, the
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value is positive if the scan encounters the real end of the buffer.
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able to move (in the full buffer, before taking account of narrowing).
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Thus, the value is positive if the scan encounters the real end of the
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buffer. The value is zero if scan encounters the end of the accessible
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portion but not the real end of the buffer.
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In an interactive call, @var{line} is the numeric prefix argument if
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one has been provided. Otherwise @var{line} is read in the minibuffer.
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@ -298,8 +302,8 @@ argument @var{count} not @code{nil} or 1, it moves forward
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@var{count}@minus{}1 lines and then to the beginning of the line.
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If this function reaches the end of the buffer (or of the accessible
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portion, if narrowing is in effect), it positions point at the end of
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the buffer. No error is signaled.
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portion, if narrowing is in effect), it positions point there. No error
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is signaled.
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@end deffn
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@deffn Command end-of-line &optional count
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@ -308,15 +312,17 @@ argument @var{count} not @code{nil} or 1, it moves forward
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@var{count}@minus{}1 lines and then to the end of the line.
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If this function reaches the end of the buffer (or of the accessible
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portion, if narrowing is in effect), it positions point at the end of
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the buffer. No error is signaled.
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portion, if narrowing is in effect), it positions point there. No error
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is signaled.
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@end deffn
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@deffn Command forward-line &optional count
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@cindex beginning of line
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This function moves point forward @var{count} lines, to the beginning of
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the line. If @var{count} is negative, it moves point
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@minus{}@var{count} lines backward, to the beginning of the line.
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@minus{}@var{count} lines backward, to the beginning of a line. If
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@var{count} is zero, it moves point to the beginning of the current
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line.
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If @code{forward-line} encounters the beginning or end of the buffer (or
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of the accessible portion) before finding that many lines, it sets point
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@ -435,7 +441,7 @@ continued onto additional screen lines. In these cases,
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@code{vertical-motion} moves point much like @code{forward-line}.
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@xref{Truncation}.
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Because the width of a given string depends on the flags which control
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Because the width of a given string depends on the flags that control
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the appearance of certain characters, @code{vertical-motion} behaves
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differently, for a given piece of text, depending on the buffer it is
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in, and even on the selected window (because the width, the truncation
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@ -462,28 +468,28 @@ This function moves point with respect to the text currently displayed
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in the selected window. It moves point to the beginning of the screen
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line @var{count} screen lines from the top of the window. If
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@var{count} is negative, that specifies a position
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@w{@minus{}@var{count}} lines from the bottom---or else the last line of
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the buffer, if the buffer ends above the specified screen position.
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@w{@minus{}@var{count}} lines from the bottom (or the last line of the
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buffer, if the buffer ends above the specified screen position).
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If @var{count} is @code{nil}, then point moves to the beginning of the
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line in the middle of the window. If the absolute value of @var{count}
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is greater than the size of the window, then point moves to the place
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which would appear on that screen line if the window were tall enough.
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that would appear on that screen line if the window were tall enough.
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This will probably cause the next redisplay to scroll to bring that
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location onto the screen.
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In an interactive call, @var{count} is the numeric prefix argument.
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The value returned is the window line number, with the top line in the
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window numbered 0.
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The value returned is the window line number point has moved to, with
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the top line in the window numbered 0.
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@end deffn
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@defun compute-motion from frompos to topos width offsets window
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This function scan through the current buffer, calculating screen
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position. It scans the current buffer forward from position @var{from},
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assuming that is at screen coordinates @var{frompos}, to position
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@var{to} or coordinates @var{topos}, whichever comes first. It returns
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the ending buffer position and screen coordinates.
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This function scans the current buffer, calculating screen positions.
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It scans the buffer forward from position @var{from}, assuming that is
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at screen coordinates @var{frompos}, to position @var{to} or coordinates
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@var{topos}, whichever comes first. It returns the ending buffer
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position and screen coordinates.
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The coordinate arguments @var{frompos} and @var{topos} are cons cells of
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the form @code{(@var{hpos} . @var{vpos})}.
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@ -501,9 +507,9 @@ column numbers in the buffer. This can be nonzero in a continuation
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line, when the previous screen lines' widths do not add up to a multiple
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of @code{tab-width}. It is always zero in a non-continuation line.
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The window @var{window} serves to specify which display table to use;
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that is its only effect. @code{compute-motion} always operates on the
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current buffer, regardless of what buffer is displayed in @var{window}.
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The window @var{window} serves only to specify which display table to
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use. @code{compute-motion} always operates on the current buffer,
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regardless of what buffer is displayed in @var{window}.
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The return value is a list of five elements:
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@ -513,27 +519,29 @@ The return value is a list of five elements:
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@noindent
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Here @var{pos} is the buffer position where the scan stopped, @var{vpos}
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is the vertical position, and @var{hpos} is the horizontal position.
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is the vertical screen position, and @var{hpos} is the horizontal screen
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position.
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The result @var{prevhpos} is the horizontal position one character back
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from @var{pos}. The result @var{contin} is @code{t} if a line was
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continued after (or within) the previous character.
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from @var{pos}. The result @var{contin} is @code{t} if the last line
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was continued after (or within) the previous character.
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For example, to find the buffer position of column @var{col} of line
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@var{line} of a certain window, pass the window's display start location
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as @var{from} and the window's upper-left coordinates as @var{frompos}.
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Pass the buffer's @code{(point-max)} as @var{to}, to limit the scan to
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the end of the visible section of the buffer, and pass @var{line} and
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the end of the accessible portion of the buffer, and pass @var{line} and
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@var{col} as @var{topos}. Here's a function that does this:
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@example
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(defun coordinates-of-position (col line)
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(car (compute-motion (window-start)
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'(0 . 0)
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(point)
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(point-max)
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(cons col line)
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(window-width)
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(cons (window-hscroll) 0))))
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(cons (window-hscroll) 0)
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(selected-window))))
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@end example
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When you use @code{compute-motion} for the minibuffer, you need to use
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@ -575,9 +583,10 @@ a vertical motion command.
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This variable controls how the vertical line motion commands operate
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when starting at the end of a line. If @code{track-eol} is
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non-@code{nil}, then vertical motion starting at the end of a line will
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keep to the ends of lines. This means moving to the end of each line
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moved onto. The value of @code{track-eol} has no effect if point is not
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at the end of a line when the first vertical motion command is given.
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keep to the ends of lines (instead of keeping to a particular column).
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This means moving to the end of each line moved onto. The value of
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@code{track-eol} has no effect if point is not at the end of a line when
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the first vertical motion command is given.
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@code{track-eol} has its effect by telling line motion commands to set
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@code{temporary-goal-column} to 9999 instead of to the current column.
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@ -616,9 +625,9 @@ A negative argument means move backward but still to a less deep spot.
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@end deffn
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@deffn Command down-list arg
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This function moves forward down @var{arg} levels of parentheses. A
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negative argument means move backward but still go down @var{arg}
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levels.
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This function moves forward into @var{arg} levels of parentheses. A
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negative argument means move backward but still go @var{arg} levels
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deeper in parentheses.
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@end deffn
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@deffn Command forward-sexp arg
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@ -655,17 +664,17 @@ to the beginning of a defun, not to the end of one.
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@end deffn
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@deffn Command end-of-defun arg
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Move forward to the @var{arg}th end of a defun. If @var{arg} is
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negative, this actually moves backward, but it still moves to the end of
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a defun, not to the beginning of one.
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This function moves forward to the @var{arg}th end of a defun. If
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@var{arg} is negative, this actually moves backward, but it still moves
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to the end of a defun, not to the beginning of one.
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@end deffn
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@defopt defun-prompt-regexp
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If non-@code{nil}, this variable holds a regular expression that
|
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specifies what text can appear before the open-parenthesis that starts a
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defun. That is to say, the a defun begins on a line which starts
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with a match for this regular expression, followed by a character
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with open-parenthesis syntax.
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defun. That is to say, a defun begins on a line that starts with a
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match for this regular expression, followed by a character with
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open-parenthesis syntax.
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@end defopt
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@node Skipping Characters
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@ -746,10 +755,10 @@ Configurations}).
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@cindex point excursion
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@cindex current buffer excursion
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The @code{save-excursion} special form saves the identity of the current
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buffer and the values of point and the mark in it, evaluates @var{forms},
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and finally restores the buffer and its saved values of point and the mark.
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All three saved values are restored even in case of an abnormal exit
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via throw or error (@pxref{Nonlocal Exits}).
|
||||
buffer and the values of point and the mark in it, evaluates
|
||||
@var{forms}, 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
|
||||
@ -805,12 +814,12 @@ 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, that usually count from the
|
||||
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 the any narrowing.
|
||||
the entire buffer regardless of any narrowing.
|
||||
|
||||
@deffn Command narrow-to-region start end
|
||||
This function sets the accessible portion of the current buffer to start
|
||||
@ -849,8 +858,8 @@ 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 throw or error (@pxref{Nonlocal Exits}). Therefore,
|
||||
this construct is a clean way to narrow a buffer temporarily.
|
||||
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.
|
||||
|
Loading…
Reference in New Issue
Block a user