Commit 4d4d2d07 authored by Richard M. Stallman's avatar Richard M. Stallman
Browse files

(Regexp Search): Add looking-back.

parent 62ea61af
......@@ -975,6 +975,32 @@ comes back" twice.
@end example
@end defun
@defun looking-back regexp &optional limit
This function returns @code{t} if @var{regexp} matches text before
point, 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}.
@example
@group
---------- Buffer: foo ----------
I read "@point{}The cat in the hat
comes back" twice.
---------- Buffer: foo ----------
(looking-back "read \"" 3)
@result{} t
(looking-back "read \"" 4)
@result{} nil
@end group
@end example
@end defun
@node POSIX Regexps
@section POSIX Regular Expression Searching
......
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