It is often useful to move point temporarily within a localized portion of the program. This is called an excursion, and it is done with the
save-excursion special form. This construct remembers the initial identity of the current buffer, and its value of point, and restores them after the excursion completes. It is the standard way to move point within one part of a program and avoid affecting the rest of the program, and is used thousands of times in the Lisp sources of Emacs.
If you only need to save and restore the identity of the current buffer, use
with-current-buffer instead (see Current Buffer). If you need to save or restore window configurations, see the forms described in Window Configurations and in Frame Configurations.
special form save-excursion body…
This special form saves the identity of the current buffer and the value of point in it, evaluates
body, and finally restores the buffer and its saved value of point. Both saved values are restored even in case of an abnormal exit via
throw or error (see Nonlocal Exits).
The value returned by
save-excursion is the result of the last form in
nil if no body forms were given.
save-excursion only saves point for the buffer that was current at the start of the excursion, any changes made to point in other buffers, during the excursion, will remain in effect afterward. This frequently leads to unintended consequences, so the byte compiler warns if you call
set-buffer during an excursion:
Warning: Use ‘with-current-buffer’ rather than
To avoid such problems, you should call
save-excursion only after setting the desired current buffer, as in the following example:
(defun append-string-to-buffer (string buffer)
"Append STRING to the end of BUFFER."
save-excursion does not restore window-buffer correspondences altered by functions such as
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
nil. See Marker Insertion Types. Therefore, when the saved point value is restored, it normally comes before the inserted text.
macro save-mark-and-excursion body…
This macro is like
save-excursion, but also saves and restores the mark location and
mark-active. This macro does what
save-excursion did before Emacs 25.1.