GNU Info
(elisp)Text Lines
Motion by Text 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.
- Command: goto-line line
This function moves point to the front of the LINEth line,
counting from line 1 at beginning of the buffer. If LINE is less
than 1, it moves point to the beginning of the buffer. If LINE is
greater than the number of lines in the buffer, it moves point to
the end of the buffer--that is, the _end of the last line_ of the
buffer. This is the only case in which `goto-line' does not
necessarily move to the beginning of a line.
If narrowing is in effect, then LINE still counts from the
beginning of the buffer, but point cannot go outside the accessible
portion. So `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 `goto-line' is the difference between LINE 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, LINE is the numeric prefix argument if one
has been provided. Otherwise LINE is read in the minibuffer.
- Command: beginning-of-line &optional count
This function moves point to the beginning of the current line.
With an argument COUNT not `nil' or 1, it moves forward COUNT-1
lines and then to the beginning of the line.
This function does not move point across a field boundary (Note:
Fields) unless doing so would move beyond there to a different
line; therefore, if COUNT is `nil' or 1, and point starts at a
field boundary, point does not move. To ignore field boundaries,
either bind `inhibit-field-text-motion' to `t', or use the
`forward-line' function instead. For instance, `(forward-line 0)'
does the same thing as `(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.
- Function: line-beginning-position &optional count
Return the position that `(beginning-of-line COUNT)' would move to.
- Command: end-of-line &optional count
This function moves point to the end of the current line. With an
argument COUNT not `nil' or 1, it moves forward COUNT-1 lines and
then to the end of the line.
This function does not move point across a field boundary (Note:
Fields) unless doing so would move beyond there to a different
line; therefore, if COUNT is `nil' or 1, and point starts at a
field boundary, point does not move. To ignore field boundaries,
bind `inhibit-field-text-motion' to `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.
- Function: line-end-position &optional count
Return the position that `(end-of-line COUNT)' would move to.
- Command: forward-line &optional count
This function moves point forward COUNT lines, to the beginning of
the line. If COUNT is negative, it moves point -COUNT lines
backward, to the beginning of a line. If COUNT is zero, it moves
point to the beginning of the current line.
If `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.
`forward-line' returns the difference between 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, COUNT is the numeric prefix argument.
- Function: count-lines start end
This function returns the number of lines between the positions
START and END in the current buffer. If START and END are equal,
then it returns 0. Otherwise it returns at least 1, even if START
and 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 `count-lines':
(defun current-line ()
"Return the vertical position of point..."
(+ (count-lines (window-start) (point))
(if (= (current-column) 0) 1 0)
-1))
Also see the functions `bolp' and `eolp' in Note: Near Point.
These functions do not move point, but test whether it is already at the
beginning or end of a line.
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