@end example
@end defun
-@defun looking-back regexp &optional limit greedy
+@defun looking-back regexp limit &optional greedy
This function returns @code{t} if @var{regexp} matches the text
immediately before point (i.e., ending at point), and @code{nil} otherwise.
Because regular expression matching works only going forward, this is
implemented by searching backwards from point for a match that ends at
point. That can be quite slow if it has to search a long distance.
-You can bound the time required by specifying @var{limit}, which says
-not to search before @var{limit}. In this case, the match that is
-found must begin at or after @var{limit}. Here's an example:
+You can bound the time required by specifying a non-@code{nil} value
+for @var{limit}, which says not to search before @var{limit}. In this
+case, the match that is found must begin at or after @var{limit}.
+Here's an example:
@example
@group
If @var{greedy} is non-@code{nil}, this function extends the match
backwards as far as possible, stopping when a single additional
-previous character cannot be part of a match for regexp. When the
-match is extended, its starting position is allowed to occur before
-@var{limit}.
+previous character cannot be part of a match for @var{regexp}. When
+the match is extended, its starting position is allowed to occur
+before @var{limit}.
@c http://debbugs.gnu.org/5689
As a general recommendation, try to avoid using @code{looking-back}
@item backup
Move back to the previous place that a question was asked about.
+@item undo
+Undo last replacement and move back to the place where that
+replacement was performed.
+
+@item undo-all
+Undo all replacements and move back to the place where the first
+replacement was performed.
+
@item edit
Enter a recursive edit to deal with this question---instead of any
other action that would normally be taken.