** debug hints
   :DATE:     2009-11-30
from mailing list

- edebug-defun: (in emacs-lisp mode, C-u C-M-x) will mark the function
  so that when it is called, the interpreter stops and you can then
  single-step through it with <SPACE>. At each point, you can press
  "e" and evaluate variables (actually arbitrary expressions).
- Insert a strategically placed (debug) call and then call the
  function.  If/when the debug call is executed, you are dropped into
  the debugger and you can then evaluate arbitrary expressions.