lisp-indent-line

[A Soare]

(defun new-lisp-indent-line (&optional whole-exp)
  "Indent current line as Lisp code.
With argument, indent any additional lines of the same expression
rigidly along with this one."
  (interactive "P")
  ...)

And also when I call it using C-u <parameter> TAB the effect is the same as the 
simple TAB.

So what it shoud have been useful for?

a soare.