These hook variables let you arrange to take notice of all changes in all buffers (or in a particular buffer, if you make them buffer-local). See also section Properties with Special Meanings, for how to detect changes to specific parts of the text.
The functions you use in these hooks should save and restore the match data if they do anything that uses regular expressions; otherwise, they will interfere in bizarre ways with the editing operations that call them.
nil
for no function). It is called just like
the functions in before-change-functions
.
nil
for no function). It is called just like the functions in
after-change-functions
.
The four variables above are temporarily bound to nil
during the
time that any of these functions is running. This means that if one of
these functions changes the buffer, that change won't run these
functions. If you do want a hook function to make changes that run
these functions, make it bind these variables back to their usual
values.
One inconvenient result of this protective feature is that you cannot
have a function in after-change-functions
or
before-change-functions
which changes the value of that variable.
But that's not a real limitation. If you want those functions to change
the list of functions to run, simply add one fixed function to the hook,
and code that function to look in another variable for other functions
to call. Here is an example:
(setq my-own-after-change-functions nil) (defun indirect-after-change-function (beg end len) (let ((list my-own-after-change-functions)) (while list (funcall (car list) beg end len) (setq list (cdr list))))) (add-hooks 'after-change-functions 'indirect-after-change-function)
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