1 files changed, 54 insertions, 0 deletions
diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index cb77148c285..faa323f733a 100644
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -816,6 +816,60 @@ Redefining FUNCTION also cancels it."
               '((depth . -100)))
   function)
 
+;;;###autoload
+;; (defun debug-on-set (symbol)
+;;   "Request FUNCTION to invoke debugger each time it is called.
+
+;; When called interactively, prompt for FUNCTION in the minibuffer.
+
+;; This works by modifying the definition of FUNCTION.  If you tell the
+;; debugger to continue, FUNCTION's execution proceeds.  If FUNCTION is a
+;; normal function or a macro written in Lisp, you can also step through
+;; its execution.  FUNCTION can also be a primitive that is not a special
+;; form, in which case stepping is not possible.  Break-on-entry for
+;; primitive functions only works when that function is called from Lisp.
+
+;; Use \\[cancel-debug-on-entry] to cancel the effect of this command.
+;; Redefining FUNCTION also cancels it."
+;;   (interactive
+;;    (let ((v (variable-at-point))
+;; 	 (enable-recursive-minibuffers t)
+;;          (orig-buffer (current-buffer))
+;; 	 val)
+;;      (setq val (completing-read
+;;                 (if (symbolp v)
+;;                     (format
+;;                      "Debug on set to symbol (default %s): " v)
+;;                   "Debug on set to symbol: ")
+;;                 #'help--symbol-completion-table
+;;                 (lambda (vv)
+;;                   ;; In case the variable only exists in the buffer
+;;                   ;; the command we switch back to that buffer before
+;;                   ;; we examine the variable.
+;;                   (with-current-buffer orig-buffer
+;;                     (or (get vv 'variable-documentation)
+;;                         (and (boundp vv) (not (keywordp vv))))))
+;;                 t nil nil
+;;                 (if (symbolp v) (symbol-name v))))
+;;      (list (if (equal val "")
+;; 	       v (intern val)))))
+
+
+
+;;   (interactive
+;;    (let* ((var-default (variable-at-point))
+;;           (var (completing-read
+;; 		(if var-default
+;; 		    (format "Debug on set to symbol (default %s): " var-default)
+;; 		  "Debug on set to symbol: ")
+;; 		nil
+;; 		#'boundp
+;; 		t nil nil (symbol-name var-default))))
+;;      (list (if (equal var "") var-default (intern var)))))
+;;   (advice-add function :before #'debug--implement-debug-on-entry
+;;               '((depth . -100)))
+;;   function)
+
 (defun debug--function-list ()
   "List of functions currently set for debug on entry."
   (let ((funs '()))