Re: How to debug modification to a variable value?

[Andreas Roehler <andreas.roehler@online.de>]

Tassilo Horn wrote:
> Andreas Roehler <andreas.roehler@online.de> writes:
> 
> Hi Andreas,
> 
>> what about to run a form with "assert MY-Values last-command
>> this-command" with a timer in background, so it's signaled as soon the
>> var is changed?
> 
> I think that timer would need to run every fraction of a second to have
> a chance to point me in the right direction.
> 
> Have a look at Davis last message.  He spotted the error: a small
> function was added to `after-save-hook' globally, but it must be there
> only buffer-locally.  The assert has to be evaluated exactly when that
> function is executed, to point me into the right direction.
> 
> I guess the watchpoint approach is more exact, 

[ ... ]

Probably,

anyway, as my small test case works so far, here the example tracking
the value of var "count":

(BTW form with "assert" don't work, why?)

(setq count '1)

(defvar zeit nil)

(defun ausgabe ()
  ;; (assert (eq count 1))
  (message "%s" "increase count, assert should fail")
  (setq count (1+ count))
  (message "%s %s %s %d" this-command last-command (eq count 1) count))

(if zeit
    (progn (cancel-timer zeit)  (setq zeit nil))
  (setq zeit (run-with-timer 0.5 1 'ausgabe)))




Andreas