Steps through elisp to find an error.

gistfile1.txt

; from http://newsgroups.derkeiler.com/Archive/Comp/comp.emacs/2005-12/msg00064.html saved for posterity
(defalias 'puffer-lesen 'eval-buffer-or-region-step-by-step)

(defun eval-buffer-or-region-step-by-step ()
"Stepps through region if activated, otherwise takes the whole buffer
evaluating last-sexp and messaging point. As `eval-last-sexp' exits
encountering an error, you may easily pick the last point.
Attention: Commands changing the current-buffer as `find-file' will
derail the check."
(interactive)
(let ((anfang (if mark-active
  	  (region-beginning)
		(point-min)))
      (ende (if mark-active
		(region-end)
	      (point-max))))
  (goto-char anfang)
  (while (and (not (eobp)) (< (point) ende))
    (progn
      (forward-sexp 1)
      (message "point %s" (point))
(eval-last-sexp nil)))))