let/let* transformation

let.el

(defun my-let-to-let* ()
  (interactive)
  (save-excursion
    (while (and (sp-beginning-of-sexp '(4)) (not (string-prefix-p (or (word-at-point) "x") "let"))))
    (sp-forward-sexp)
    (if (looking-back "\\*") 
        (delete-backward-char 1)
      (insert "*"))))