* lisp/subr.el (with-wrapper-hook): Declare obsolete.

[bpt/emacs.git] / lisp / simple.el

diff --git a/lisp/simple.el b/lisp/simple.el
index 5adb634..3f28b84 100644 (file)
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -3291,46 +3291,33 @@ These commands include \\[set-mark-command] and \\[start-kbd-macro]."
 \f
 
 (defvar filter-buffer-substring-functions nil
-  "This variable is a wrapper hook around `filter-buffer-substring'.
-Each member of the hook should be a function accepting four arguments:
-\(FUN BEG END DELETE), where FUN is itself a function of three arguments
+  "This variable is a wrapper hook around `filter-buffer-substring'.")
+(make-obsolete-variable 'filter-buffer-substring-functions
+                        'filter-buffer-substring-function "24.4")
+
+(defvar filter-buffer-substring-function #'buffer-substring--filter
+  "Function to perform the filtering in `filter-buffer-substring'.
+The function is called with 3 arguments:
 \(BEG END DELETE).  The arguments BEG, END, and DELETE are the same
 as those of `filter-buffer-substring' in each case.
-
-The first hook function to be called receives a FUN equivalent
-to the default operation of `filter-buffer-substring',
-i.e. one that returns the buffer-substring between BEG and
-END (processed by any `buffer-substring-filters').  Normally,
-the hook function will call FUN and then do its own processing
-of the result.  The next hook function receives a FUN equivalent
-to the previous hook function, calls it, and does its own
-processing, and so on.  The overall result is that of all hook
-functions acting in sequence.
-
-Any hook may choose not to call FUN though, in which case it
-effectively replaces the default behavior with whatever it chooses.
-Of course, a later hook function may do the same thing.")
+It should return the buffer substring between BEG and END, after filtering.")
 
 (defvar buffer-substring-filters nil
   "List of filter functions for `filter-buffer-substring'.
 Each function must accept a single argument, a string, and return
 a string.  The buffer substring is passed to the first function
 in the list, and the return value of each function is passed to
-the next.  The final result (if `buffer-substring-filters' is
-nil, this is the unfiltered buffer-substring) is passed to the
-first function on `filter-buffer-substring-functions'.
-
+the next.
 As a special convention, point is set to the start of the buffer text
 being operated on (i.e., the first argument of `filter-buffer-substring')
 before these functions are called.")
 (make-obsolete-variable 'buffer-substring-filters
-                        'filter-buffer-substring-functions "24.1")
+                        'filter-buffer-substring-function "24.1")
 
 (defun filter-buffer-substring (beg end &optional delete)
   "Return the buffer substring between BEG and END, after filtering.
-The wrapper hook `filter-buffer-substring-functions' performs
-the actual filtering.  The obsolete variable `buffer-substring-filters'
-is also consulted.  If both of these are nil, no filtering is done.
+The hook `filter-buffer-substring-function' performs the actual filtering.
+By default, no filtering is done.
 
 If DELETE is non-nil, the text between BEG and END is deleted
 from the buffer.
@@ -3338,9 +3325,12 @@ from the buffer.
 This function should be used instead of `buffer-substring',
 `buffer-substring-no-properties', or `delete-and-extract-region'
 when you want to allow filtering to take place.  For example,
-major or minor modes can use `filter-buffer-substring-functions' to
+major or minor modes can use `filter-buffer-substring-function' to
 extract characters that are special to a buffer, and should not
 be copied into other buffers."
+  (funcall filter-buffer-substring-function beg end delete))
+
+(defun buffer-substring--filter (beg end &optional delete)
   (with-wrapper-hook filter-buffer-substring-functions (beg end delete)
     (cond
      ((or delete buffer-substring-filters)