Álvaro Ramírez

Want to re-evaluate defvars and modify variables? eval-defun (bound to C-M-x) can help. From the manual:

If the current defun is actually a call to `defvar', then reset the variable using its initial value expression even if the variable already has some other value. (Normally `defvar' does not change the variable's value if it already has a value.) Treat `defcustom' similarly.